New insights into Blimp-1 in T lymphocytes: a divergent regulator of cell destiny and effector function.

PubMed

Fu, Shin-Huei; Yeh, Li-Tzu; Chu, Chin-Chen; Yen, B Lin-Ju; Sytwu, Huey-Kang

2017-07-21

B lymphocyte-induced maturation protein-1 (Blimp-1) serves as a master regulator of the development and function of antibody-producing B cells. Given that its function in T lymphocytes has been identified within the past decade, we review recent findings with emphasis on its role in coordinated control of gene expression during the development, differentiation, and function of T cells. Expression of Blimp-1 is mainly confined to activated T cells and is essential for the production of interleukin (IL)-10 by a subset of forkhead box (Fox)p3 + regulatory T cells with an effector phenotype. Blimp-1 is also required to induce cell elimination in the thymus and critically modulates peripheral T cell activation and proliferation. In addition, Blimp-1 promotes T helper (Th) 2 lineage commitment and limits Th1, Th17 and follicular helper T cell differentiation. Furthermore, Blimp-1 coordinates with other transcription factors to regulate expression of IL-2, IL-21 and IL-10 in effector T lymphocytes. In CD8 + T cells, Blimp-1 expression is distinct in heterogeneous populations at the stages of clonal expansion, differentiation, contraction and memory formation when they encounter antigens. Moreover, Blimp-1 plays a fundamental role in coordinating cytokine receptor signaling networks and transcriptional programs to regulate diverse aspects of the formation and function of effector and memory CD8 + T cells and their exhaustion. Blimp-1 also functions as a gatekeeper of T cell activation and suppression to prevent or dampen autoimmune disease, antiviral responses and antitumor immunity. In this review, we discuss the emerging roles of Blimp-1 in the complex regulation of gene networks that regulate the destiny and effector function of T cells and provide a Blimp-1-dominated transcriptional framework for T lymphocyte homeostasis.

Tailored immune responses: novel effector helper T cell subsets in protective immunity.

PubMed

Kara, Ervin E; Comerford, Iain; Fenix, Kevin A; Bastow, Cameron R; Gregor, Carly E; McKenzie, Duncan R; McColl, Shaun R

2014-02-01

Differentiation of naïve CD4⁺ cells into functionally distinct effector helper T cell subsets, characterised by distinct "cytokine signatures," is a cardinal strategy employed by the mammalian immune system to efficiently deal with the rapidly evolving array of pathogenic microorganisms encountered by the host. Since the T(H)1/T(H)2 paradigm was first described by Mosmann and Coffman, research in the field of helper T cell biology has grown exponentially with seven functionally unique subsets having now been described. In this review, recent insights into the molecular mechanisms that govern differentiation and function of effector helper T cell subsets will be discussed in the context of microbial infections, with a focus on how these different helper T cell subsets orchestrate immune responses tailored to combat the nature of the pathogenic threat encountered.

Mast cells counteract regulatory T-cell suppression through interleukin-6 and OX40/OX40L axis toward Th17-cell differentiation.

PubMed

Piconese, Silvia; Gri, Giorgia; Tripodo, Claudio; Musio, Silvia; Gorzanelli, Andrea; Frossi, Barbara; Pedotti, Rosetta; Pucillo, Carlo E; Colombo, Mario P

2009-09-24

The development of inflammatory diseases implies inactivation of regulatory T (Treg) cells through mechanisms that still are largely unknown. Here we showed that mast cells (MCs), an early source of inflammatory mediators, are able to counteract Treg inhibition over effector T cells. To gain insight into the molecules involved in their interplay, we set up an in vitro system in which all 3 cellular components were put in contact. Reversal of Treg suppression required T cell-derived interleukin-6 (IL-6) and the OX40/OX40L axis. In the presence of activated MCs, concomitant abundance of IL-6 and paucity of Th1/Th2 cytokines skewed Tregs and effector T cells into IL-17-producing T cells (Th17). In vivo analysis of lymph nodes hosting T-cell priming in experimental autoimmune encephalomyelitis revealed activated MCs, Tregs, and Th17 cells displaying tight spatial interactions, further supporting the occurrence of an MC-mediated inhibition of Treg suppression in the establishment of Th17-mediated inflammatory responses.

Suppression of IL-7-dependent Effector T-cell Expansion by Multipotent Adult Progenitor Cells and PGE2

PubMed Central

Reading, James L; Vaes, Bart; Hull, Caroline; Sabbah, Shereen; Hayday, Thomas; Wang, Nancy S; DiPiero, Anthony; Lehman, Nicholas A; Taggart, Jen M; Carty, Fiona; English, Karen; Pinxteren, Jef; Deans, Robert; Ting, Anthony E; Tree, Timothy I M

2015-01-01

T-cell depletion therapy is used to prevent acute allograft rejection, treat autoimmunity and create space for bone marrow or hematopoietic cell transplantation. The evolved response to T-cell loss is a transient increase in IL-7 that drives compensatory homeostatic proliferation (HP) of mature T cells. Paradoxically, the exaggerated form of this process that occurs following lymphodepletion expands effector T-cells, often causing loss of immunological tolerance that results in rapid graft rejection, autoimmunity, and exacerbated graft-versus-host disease (GVHD). While standard immune suppression is unable to treat these pathologies, growing evidence suggests that manipulating the incipient process of HP increases allograft survival, prevents autoimmunity, and markedly reduces GVHD. Multipotent adult progenitor cells (MAPC) are a clinical grade immunomodulatory cell therapy known to alter γ-chain cytokine responses in T-cells. Herein, we demonstrate that MAPC regulate HP of human T-cells, prevent the expansion of Th1, Th17, and Th22 effectors, and block the development of pathogenic allograft responses. This occurs via IL-1β-primed secretion of PGE2 and activates T-cell intrinsic regulatory mechanisms (SOCS2, GADD45A). These data provide proof-of-principle that HP of human T-cells can be targeted by cellular and molecular therapies and lays a basis for the development of novel strategies to prevent immunopathology in lymphodepleted patients. PMID:26216515

Cellular and Molecular Dynamics of Th17 Differentiation and its Developmental Plasticity in the Intestinal Immune Response

PubMed Central

Bhaumik, Suniti; Basu, Rajatava

2017-01-01

After emerging from the thymus, naive CD4 T cells circulate through secondary lymphoid tissues, including gut-associated lymphoid tissue of the intestine. The activation of naïve CD4 T cells by antigen-presenting cells offering cognate antigen initiate differentiation programs that lead to the development of highly specialized T helper (Th) cell lineages. Although initially believed that developmental programing of effector T cells such as T helper 1 (Th1) or T helper 2 (Th2) resulted in irreversible commitment to a fixed fate, subsequent studies have demonstrated greater flexibility, or plasticity, in effector T cell stability than originally conceived. This is particularly so for the Th17 subset, differentiation of which is a highly dynamic process with overlapping developmental axes with inducible regulatory T (iTreg), T helper 22 (Th22), and Th1 cells. Accordingly, intermediary stages of Th17 cells are found in various tissues, which co-express lineage-specific transcription factor(s) or cytokine(s) of developmentally related CD4 T cell subsets. A highly specialized tissue like that of the intestine, which harbors the largest immune compartment of the body, adds several layers of complexity to the intricate process of Th differentiation. Due to constant exposure to millions of commensal microbes and periodic exposure to pathogens, the intestinal mucosa maintains a delicate balance between regulatory and effector T cells. It is becoming increasingly clear that equilibrium between tolerogenic and inflammatory axes is maintained in the intestine by shuttling the flexible genetic programming of a developing CD4 T cell along the developmental axis of iTreg, Th17, Th22, and Th1 subsets. Currently, Th17 plasticity remains an unresolved concern in the field of clinical research as targeting Th17 cells to cure immune-mediated disease might also target its related subsets. In this review, we discuss the expanding sphere of Th17 plasticity through its shared developmental axes with related cellular subsets such as Th22, Th1, and iTreg in the context of intestinal inflammation and also examine the molecular and epigenetic features of Th17 cells that mediate these overlapping developmental programs. PMID:28408906

CD4+ T cells are required to contain early extrathoracic TB dissemination and sustain multi-effector functions of CD8+ T and CD3− lymphocytes

PubMed Central

Yao, Shuyu; Huang, Dan; Chen, Crystal Y.; Halliday, Lisa; Wang, Richard C.; Chen, Zheng W.

2014-01-01

The possibility that CD4+ T cells can act as “innate-like” cells to contain very-early M. tuberculosis (Mtb) dissemination and function as master helpers to sustain multiple effector functions of CD8+ T cells and CD3-negative lymphocytes during development of adaptive immunity against primary tuberculosis(TB) has not been demonstrated. We showed that pulmonary Mtb infection of CD4-depleted macaques surprisingly led to very-early extrathoracic Mtb dissemination, whereas CD4 deficiency clearly resulted in rapid TB progression. CD4 depletion during Mtb infection revealed the ability of CD8+ T cells to compensate and rapidly differentiate to Th17-like/Th1-like, and cytotoxic-like effectors, but these effector functions were subsequently unsustainable due to CD4 deficiency. While CD3-negative non-T lymphocytes in presence of CD4+ T cells developed predominant Th22-like and NK-like (perforin production) responses to Mtb infection, CD4 depletion abrogated these Th22-/NK-like effector functions and favored IL-17 production by CD3-negative lymphocytes. CD4-depleted macaques exhibited no or few pulmonary T effector cells constitutively producing IFN-γ, TNFα, IL-17, IL-22, and perforin at the endpoint of more severe TB, but presented pulmonary IL-4+ T effectors. TB granulomas in CD4-depleted macaques contained fewer IL-22+ and perforin+ cells despite presence of IL-17+ and IL-4+ cells. These results implicate previously-unknown “innate-like” ability of CD4+ T cells to contain extrathoracic Mtb dissemination at very early stage. Data also suggest that CD4+ T cells are required to sustain multiple effector functions of CD8+ T cells and CD3-negative lymphocytes and to prevent rapid TB progression during Mtb infection of nonhuman primates. PMID:24489088

Host Th1/Th2 immune response to Taenia solium cyst antigens in relation to cyst burden of neurocysticercosis.

PubMed

Tharmalingam, J; Prabhakar, A T; Gangadaran, P; Dorny, P; Vercruysse, J; Geldhof, P; Rajshekhar, V; Alexander, M; Oommen, A

2016-10-01

Neurocysticercosis (NCC), Taenia solium larval infection of the brain, is an important cause of acquired seizures in endemic countries, which relate to number, location and degenerating cysts in the brain. Multicyst infections are common in endemic countries although single-cyst infection prevails in India. Single-cyst infections in an endemic country suggest a role for host immunity limiting the infection. This study examined ex vivo CD4(+) T cells and in vitro Th1 and Th2 cytokine responses to T. solium cyst antigens of peripheral blood mononuclear cells of healthy subjects from endemic and nonendemic regions and of single- and multicyst-infected patients for association with cyst burden of NCC. T. solium cyst antigens elicited a Th1 cytokine response in healthy subjects of T. solium-endemic and T. solium-non-endemic regions and those with single-cyst infections and a Th2 cytokine response from subjects with multicyst neurocysticercosis. Multicyst neurocysticercosis subjects also exhibited low levels of effector memory CD4(+) T cells. Th1 cytokine response of T. solium exposure and low infectious loads may aid in limiting cyst number. Th2 cytokines and low effector T cells may enable multiple-cyst infections to establish and persist. © 2016 John Wiley & Sons Ltd.

Cyclic AMP-induced Chromatin Changes Support the NFATc-mediated Recruitment of GATA-3 to the Interleukin 5 Promoter*

PubMed Central

Klein-Hessling, Stefan; Bopp, Tobias; Jha, Mithilesh K.; Schmidt, Arthur; Miyatake, Shoichiro; Schmitt, Edgar; Serfling, Edgar

2008-01-01

Elevated intracellular cyclic AMP levels, which suppress the proliferation of naive T cells and type 1 T helper (Th1) cells are a property of T helper 2 (Th2) cells and regulatory T cells. While cyclic AMP signals interfere with the IL-2 promoter induction, they support the induction of Th2-type genes, in particular of il-5 gene. We show here that cyclic AMP signals support the generation of three inducible DNase I hypersensitive chromatin sites over the il-5 locus, including its promoter region. In addition, cyclic AMP signals enhance histone H3 acetylation at the IL-5 promoter and the concerted binding of GATA-3 and NFATc to the promoter. This is facilitated by direct protein-protein interactions involving the C-terminal Zn2+-finger of GATA-3 and the C-terminal region of the NFATc1 DNA binding domain. Because inhibition of NFATc binding to the IL-5 promoter in vivo also affects the binding of GATA-3, one may conclude that upon induction of Th2 effector cells NFATc recruits GATA-3 to Th2-type genes. These data demonstrate the functional importance of cyclic AMP signals for the interplay between GATA-3 and NFATc factors in the transcriptional control of lymphokine expression in Th2 effector cells. PMID:18772129

In planta processing and glycosylation of a nematode CLE effector and its interaction with a CLV2-like receptor to promote parasitism

USDA-ARS?s Scientific Manuscript database

Like other biotrophic plant pathogens, plant-parasitic nematodes secrete effector proteins into host cells to facilitate infection. Effector proteins that mimic plant CLAVATA3/ESR (CLE)-like proteins have been identified in several cyst nematodes including the potato cyst nematode (PCN); however, th...

Single-Cell Tracking Reveals a Role for Pre-Existing CCR5+ Memory Th1 Cells in the Control of Rhinovirus-A39 After Experimental Challenge in Humans.

PubMed

Muehling, Lyndsey M; Turner, Ronald B; Brown, Kenneth B; Wright, Paul W; Patrie, James T; Lahtinen, Sampo J; Lehtinen, Markus J; Kwok, William W; Woodfolk, Judith A

2018-01-17

Little is known about T cells that respond to human rhinovirus in vivo, due to timing of infection, viral diversity, and complex T-cell specificities. We tracked circulating CD4+ T cells with identical epitope specificities that responded to intranasal challenge with rhinovirus (RV)-A39, and we assessed T-cell signatures in the nose. Cells were monitored using a mixture of 2 capsid-specific major histocompatibility complex II tetramers over a 7-week period, before and after RV-A39 challenge, in 16 human leukocyte antigen-DR4+ subjects who participated in a trial of Bifidobacterium lactis (Bl-04) supplementation. Pre-existing tetramer+ T cells were linked to delayed viral shedding, enriched for activated CCR5+ Th1 effectors, and included a minor interleukin-21+ T follicular helper cell subset. After RV challenge, expansion and activation of virus-specific CCR5+ Th1 effectors was restricted to subjects who had a rise in neutralizing antibodies, and tetramer-negative CCR5+ effector memory types were comodulated. In the nose, CXCR3-CCR5+ T cells present during acute infection were activated effector memory type, whereas CXCR3+ cells were central memory type, and cognate chemokine ligands were elevated over baseline. Probiotic had no T-cell effects. We conclude that virus-specific CCR5+ effector memory CD4+ T cells primed by previous exposure to related viruses contribute to the control of rhinovirus. © The Author(s) 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Obaculactone suppresses Th1 effector cell function through down-regulation of T-bet and prolongs skin graft survival in mice.

PubMed

Gong, Fangyuan; Shen, Yan; Zhang, Qi; Sun, Yang; Tang, Jiayu; Tao, Feifei; Xu, Qiang

2010-07-15

Allograft rejection is a predominantly Th1 immune response. In this study, we showed that obaculactone, a natural compound derived from citrus fruit, prolonged skin graft survival in mice when treated after but not before transplantation. Furthermore, obaculactone inhibited alloantigen-specific production of Th1 cytokine IFN-gamma as well as proinflammatory cytokine IL-2, TNFalpha and IL-6. In parallel, IL-10 production was markedly up-regulated. Obaculactone significantly enhanced the percentage of CD4(+)CD25(+)Foxp3(+) Treg cells in the CD4(+) splenocytes without any effect on their inhibitory function. In vitro and in vivo tests showed obaculactone down-regulated T-bet expression in Th1 effector cells. Taken together, the unique immunomodulatory properties might qualify obaculactone as a putative, therapeutic compound for the treatment of Th1-driven diseases, including transplant rejection. 2010 Elsevier Inc. All rights reserved.

PKCλ/ι regulates Th17 differentiation and house dust mite-induced allergic airway inflammation.

PubMed

Yang, Yingying; Dong, Panpan; Zhao, Jing; Zhou, Wei; Zhou, Yonghua; Xu, Yongliang; Mei, Congjin; Guo, Fukun; Zheng, Yi; Yang, Jun-Qi

2018-03-01

Asthma is a chronic airway inflammation in which Th2 and Th17 cells play critical roles in its pathogenesis. We have reported that atypical protein kinase (PKC) λ/ι is a new regulator for Th2 differentiation and function. However, the role of PKCλ/ι for Th17 cells remains elusive. In this study, we explored the effect of PKCλ/ι on Th17 cells in the context of ex vivo cell culture systems and an in vivo murine model of allergic airway inflammation with the use of activated T cell-specific conditional PKCλ/ι-deficient mice. Our findings indicate that PKCλ/ι regulates Th17 cells. The secretion of Th17 effector cytokines, including IL-17, IL-21 and IL-22, were inhibited from PKCλ/ι-deficient T cells under non-skewing or Th17-skewing culture conditions. Moreover, the impaired Th17 differentiation and function by the PKCλ/ι-deficiency was associated with the downregulation of Stat3 and Rorγt, key Th17 transcription factors. We developed a model of Th17 and neutrophil-involved allergic airway inflammation by intratracheal inoculation of house dust mites. PKCλ/ι-deficiency significantly inhibited airway inflammations. The infiltrating cells in the lungs and bronchoalveolar lavage fluids were significantly reduced in conditional PKCλ/ι-deficient mice. Th17 effector cytokines were reduced in the bronchoalveolar lavage fluids and lungs at protein and mRNA levels. Thus, PKCλ/ι emerges as a critical regulator of Th17 differentiation and allergic airway hyperresponsiveness. Copyright © 2018 Elsevier B.V. All rights reserved.

Pathological and therapeutic roles of innate lymphoid cells in diverse diseases.

PubMed

Kim, Jisu; Kim, Geon; Min, Hyeyoung

2017-11-01

Innate lymphoid cells (ILCs) are a recently defined type of innate-immunity cells that belong to the lymphoid lineage and have lymphoid morphology but do not express an antigen-specific B cell or T-cell receptor. ILCs regulate immune functions prior to the formation of adaptive immunity and exert effector functions through a cytokine release. ILCs have been classified into three groups according to the transcription factors that regulate their development and function and the effector cytokines they produce. Of note, ILCs resemble T helper (Th) cells, such as Th1, Th2, and Th17 cells, and show a similar dependence on transcription factors and distinct cytokine production. Despite their short history in immunology, ILCs have received much attention, and numerous studies have revealed biological functions of ILCs including host defense against pathogens, inflammation, tissue repair, and metabolic homeostasis. Here, we describe recent findings about the roles of ILCs in the pathogenesis of various diseases and potential therapeutic targets.

Macrophages as IL-25/IL-33-responsive cells play an important role in the induction of type 2 immunity

USDA-ARS?s Scientific Manuscript database

Th2 immunity is essential for the host protection against nematode infection, while detrimental in allergic inflammation or asthma. Although many of the details regarding the cellular and molecular events in Th2 immunity have been described, the specific cell types and effector molecules involved i...

RORC2 is involved in T cell polarization through interaction with the FOXP3 promoter.

PubMed

Burgler, Simone; Mantel, Pierre-Yves; Bassin, Claudio; Ouaked, Nadia; Akdis, Cezmi A; Schmidt-Weber, Carsten B

2010-06-01

The process of Th cell differentiation toward polarized effector T cells tailors specific immunity against invading pathogens while allowing tolerance against commensal microorganisms, harmless allergens, or autologous Ags. Identification of the mechanisms underlying this polarization process is therefore central to understand how the immune system confers immunity and tolerance. The present study demonstrates that retinoic acid receptor-related orphan receptor C2 (RORC2), a key transcription factor in Th17 cell development, inhibits FOXP3 expression in human T cells. Although overexpression of RORC2 in naive T cells reduces levels of FOXP3, small interfering RNA-mediated knockdown of RORC2 enhances its expression. RORC2 mediates this inhibition at least partially by binding to two out of four ROR-responsive elements on the FOXP3 promoter. Knockdown of RORC2 promotes high FOXP3 levels and decreased expression of proinflammatory cytokines beta form of pro-IL-1, IL-6, IL-17A, IFN-gamma, and TNF-alpha in differentiating naive T cells, suggesting that the role of RORC2 in Th17 cell development involves not only induction of Th17-characteristic genes, but also suppression of regulatory T cell-specific programs. Together, this study identifies RORC2 as a polarizing factor in transcriptional cross-regulation and provides novel viewpoints on the control of immune tolerance versus effector immune responses.

Critical requirement for the Wiskott-Aldrich syndrome protein in Th2 effector function

USDA-ARS?s Scientific Manuscript database

The Wiskott-Aldrich syndrome protein (WASp) regulates actin polymerization via activation of Arp2/3 and plays a role in the dynamics of the immunological synapse. How these events influence subsequent gene expression and effector function is unclear. We studied the role of WASp in CD4+ T cell effe...

Notch regulates Th17 differentiation and controls trafficking of IL-17 and metabolic regulators within Th17 cells in a context-dependent manner

PubMed Central

Coutaz, Manuel; Hurrell, Benjamin P.; Auderset, Floriane; Wang, Haiping; Siegert, Stefanie; Eberl, Gerard; Ho, Ping-Chih; Radtke, Freddy; Tacchini-Cottier, Fabienne

2016-01-01

Th17 cells play critical roles in host defense and autoimmunity. Emerging data support a role for Notch signaling in Th17 cell differentiation but whether it is a positive or negative regulator remains unclear. We report here that T cell-specific deletion of Notch receptors enhances Th17 cell differentiation in the gut, with a corresponding increase in IL-17 secretion. An increase in Th17 cell frequency was similarly observed following immunization of T cell specific Notch mutant mice with OVA/CFA. However, in this setting, Th17 cytokine secretion was impaired, and increased intracellular retention of IL-17 was observed. Intracellular IL-17 co-localized with the CD71 iron transporter in the draining lymph node of both control and Notch-deficient Th17 cells. Immunization induced CD71 surface expression in control, but not in Notch-deficient Th17 cells, revealing defective CD71 intracellular transport in absence of Notch signaling. Moreover, Notch receptor deficient Th17 cells had impaired mTORC2 activity. These data reveal a context-dependent impact of Notch on vesicular transport during high metabolic demand suggesting a role for Notch signaling in the bridging of T cell metabolic demands and effector functions. Collectively, our findings indicate a prominent regulatory role for Notch signaling in the fine-tuning of Th17 cell differentiation and effector function. PMID:27974744

The IL23R R381Q Gene Variant Protects against Immune-Mediated Diseases by Impairing IL-23-Induced Th17 Effector Response in Humans

PubMed Central

Di Meglio, Paola; Di Cesare, Antonella; Laggner, Ute; Chu, Chung-Ching; Napolitano, Luca; Villanova, Federica; Tosi, Isabella; Capon, Francesca; Trembath, Richard C.; Peris, Ketty; Nestle, Frank O.

2011-01-01

IL-23 and Th17 cells are key players in tissue immunosurveillance and are implicated in human immune-mediated diseases. Genome-wide association studies have shown that the IL23R R381Q gene variant protects against psoriasis, Crohn's disease and ankylosing spondylitis. We investigated the immunological consequences of the protective IL23R R381Q gene variant in healthy donors. The IL23R R381Q gene variant had no major effect on Th17 cell differentiation as the frequency of circulating Th17 cells was similar in carriers of the IL23R protective (A) and common (G) allele. Accordingly, Th17 cells generated from A and G donors produced similar amounts of Th17 cytokines. However, IL-23-mediated Th17 cell effector function was impaired, as Th17 cells from A allele carriers had significantly reduced IL-23-induced IL-17A production and STAT3 phosphorylation compared to G allele carriers. Our functional analysis of a human disease-associated gene variant demonstrates that IL23R R381Q exerts its protective effects through selective attenuation of IL-23-induced Th17 cell effector function without interfering with Th17 differentiation, and highlights its importance in the protection against IL-23-induced tissue pathologies. PMID:21364948

The IL23R R381Q gene variant protects against immune-mediated diseases by impairing IL-23-induced Th17 effector response in humans.

PubMed

Di Meglio, Paola; Di Cesare, Antonella; Laggner, Ute; Chu, Chung-Ching; Napolitano, Luca; Villanova, Federica; Tosi, Isabella; Capon, Francesca; Trembath, Richard C; Peris, Ketty; Nestle, Frank O

2011-02-22

IL-23 and Th17 cells are key players in tissue immunosurveillance and are implicated in human immune-mediated diseases. Genome-wide association studies have shown that the IL23R R381Q gene variant protects against psoriasis, Crohn's disease and ankylosing spondylitis. We investigated the immunological consequences of the protective IL23R R381Q gene variant in healthy donors. The IL23R R381Q gene variant had no major effect on Th17 cell differentiation as the frequency of circulating Th17 cells was similar in carriers of the IL23R protective (A) and common (G) allele. Accordingly, Th17 cells generated from A and G donors produced similar amounts of Th17 cytokines. However, IL-23-mediated Th17 cell effector function was impaired, as Th17 cells from A allele carriers had significantly reduced IL-23-induced IL-17A production and STAT3 phosphorylation compared to G allele carriers. Our functional analysis of a human disease-associated gene variant demonstrates that IL23R R381Q exerts its protective effects through selective attenuation of IL-23-induced Th17 cell effector function without interfering with Th17 differentiation, and highlights its importance in the protection against IL-23-induced tissue pathologies.

B Cell Depletion Therapy Normalizes Circulating Follicular Th Cells in Primary Sjögren Syndrome.

PubMed

Verstappen, Gwenny M; Kroese, Frans G M; Meiners, Petra M; Corneth, Odilia B; Huitema, Minke G; Haacke, Erlin A; van der Vegt, Bert; Arends, Suzanne; Vissink, Arjan; Bootsma, Hendrika; Abdulahad, Wayel H

2017-01-01

To assess the effect of B cell depletion therapy on effector CD4+ T cell homeostasis and its relation to objective measures of disease activity in patients with primary Sjögren syndrome (pSS). Twenty-four patients with pSS treated with rituximab (RTX) and 24 healthy controls (HC) were included. Frequencies of circulating effector CD4+ T cell subsets were examined by flow cytometry at baseline and 16, 24, 36, and 48 weeks after the first RTX infusion. Th1, Th2, follicular Th (TFH), and Th17 cells were discerned based on surface marker expression patterns. Additionally, intracellular cytokine staining was performed for interferon-γ, interleukin (IL)-4, IL-21, and IL-17 and serum levels of these cytokines were analyzed. In patients with pSS, frequencies of circulating TFH cells and Th17 cells were increased at baseline compared with HC, whereas frequencies of Th1 and Th2 cells were unchanged. B cell depletion therapy resulted in a pronounced decrease in circulating TFH cells, whereas Th17 cells were only slightly lowered. Frequencies of IL-21-producing and IL-17-producing CD4+ T cells and serum levels of IL-21 and IL-17 were also reduced. Importantly, the decrease in circulating TFH cells was associated with lower systemic disease activity over time, as measured by the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index scores and serum IgG levels. B cell depletion therapy in patients with pSS results in normalization of the elevated levels of circulating TFH cells. This reduction is associated with improved objective clinical disease activity measures. Our observations illustrate the pivotal role of the crosstalk between B cells and TFH cells in the pathogenesis of pSS.

Dendritic Cells Induce a Subpopulation of IL-12Rβ2-Expressing Treg that Specifically Consumes IL-12 to Control Th1 Responses

PubMed Central

Sela, Uri; Park, Chae Gyu; Park, Andrew; Olds, Peter; Wang, Shu; Fischetti, Vincent A.

2016-01-01

Cytokines secreted from dendritic cells (DCs) play an important role in the regulation of T helper (Th) cell differentiation and activation into effector cells. Therefore, controlling cytokine secretion from DCs may potentially regulate Th differentiation/activation. DCs also induce de-novo generation of regulatory T cells (Treg) that modulate the immune response. In the current study we used the mixed leukocyte reaction (MLR) to investigate the effect of allospecific Treg on IL-12, TNFα and IL-6 secretion by DCs. Treg cells were found to markedly down-regulate IL-12 secretion from DCs following stimulation with TLR7/8 agonist. This down-regulation of IL-12 was neither due to a direct suppression of its production by the DCs nor a result of marked DC death. We found that IL-12 was rather actively consumed by Treg cells. IL-12 consumption was mediated by a subpopulation of IL-12Rβ2-expressing Treg cells and was dependent on MHC class-II expressed on dendritic cells. Furthermore, IL-12 consumption by Tregs increased their suppressive effect on T cell proliferation and Th1 activation. These results provide a new pathway of Th1 response regulation where IL-12 secreted by DCs is consumed by a sub-population of IL-12Rβ2-expressing Treg cells. Consumption of IL-12 by Tregs not only reduces the availability of IL-12 to Th effector cells but also enhances the Treg immunosuppressive effect. This DC-induced IL-12Rβ2-expressing Treg subpopulation may have a therapeutic advantage in suppressing Th1 mediated autoimmunity. PMID:26745371

Steady State Dendritic Cells Present Parenchymal Self-Antigen and Contribute to, but Are Not Essential for, Tolerization of Naive and Th1 Effector CD4 Cells1

PubMed Central

Hagymasi, Adam T.; Slaiby, Aaron M.; Mihalyo, Marianne A.; Qui, Harry Z.; Zammit, David J.; Lefrançois, Leo; Adler, Adam J.

2010-01-01

Bone marrow-derived APC are critical for both priming effector/memory T cell responses to pathogens and inducing peripheral tolerance in self-reactive T cells. In particular, dendritic cells (DC) can acquire peripheral self-Ags under steady state conditions and are thought to present them to cognate T cells in a default tolerogenic manner, whereas exposure to pathogen-associated inflammatory mediators during the acquisition of pathogen-derived Ags appears to reprogram DCs to prime effector and memory T cell function. Recent studies have confirmed the critical role of DCs in priming CD8 cell effector responses to certain pathogens, although the necessity of steady state DCs in programming T cell tolerance to peripheral self-Ags has not been directly tested. In the current study, the role of steady state DCs in programming self-reactive CD4 cell peripheral tolerance was assessed by combining the CD11c-diphtheria toxin receptor transgenic system, in which DC can be depleted via treatment with diphtheria toxin, with a TCR-transgenic adoptive transfer system in which either naive or Th1 effector CD4 cells are induced to undergo tolerization after exposure to cognate parenchymally derived self-Ag. Although steady state DCs present parenchymal self-Ag and contribute to the tolerization of cognate naive and Th1 effector CD4 cells, they are not essential, indicating the involvement of a non-DC tolerogenic APC population(s). Tolerogenic APCs, however, do not require the cooperation of CD4+CD25+ regulatory T cells. Similarly, DC were required for maximal priming of naive CD4 cells to vaccinia viral-Ag, but priming could still occur in the absence of DC. PMID:17641018

Opioid growth factor and low-dose naltrexone impair central nervous system infiltration by CD4 + T lymphocytes in established experimental autoimmune encephalomyelitis, a model of multiple sclerosis.

PubMed

Hammer, Leslie A; Waldner, Hanspeter; Zagon, Ian S; McLaughlin, Patricia J

2016-01-01

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS), characterized by infiltrating myelin-reactive T lymphocytes and demyelinating lesions. Experimental autoimmune encephalomyelitis (EAE) is the animal model widely utilized to study MS. EAE is mediated by CD4(+) T cells and can be induced in EAE-susceptible mice through immunization with a myelin antigen, such as proteolipid protein 139-151 (PLP139-151) in SJL mice. In this PLP-induced EAE model, autoreactive CD4(+) T cells migrate from peripheral tissues into the CNS where they are reactivated resulting in CNS damage. Th1 and Th17 cells produce the pro-inflammatory cytokines IFNγ and IL-17, respectively, that have been shown to have pathogenic roles in EAE and MS. Anti-inflammatory Th2, IL-4 secreting cells, have been indicated to inhibit EAE exacerbation. However, given the inflammatory environment of EAE, Th2 effector cells are outnumbered by Th1/Th17 cells. Regulatory CD4(+) T cells suppress immune reactions and have been demonstrated to be dysfunctional in MS patients. Opioid growth factor (OGF), chemically termed [Met(5)]-enkephalin, is a negative growth factor that interacts with the OGF receptor. The OGF-OGFr axis can be activated through exogenous administration of OGF or a low dosage of naltrexone (LDN), an opioid antagonist. We have previously demonstrated that modulation of the OGF-OGFr axis results in alleviation from relapse-remitting EAE, and that CNS-infiltrating CD3(+) T cells are diminished with exogenous OGF or intermittent blockade with LDN administration. In this paper, we aimed to determine whether OGF or LDN alter the Th effector responses of CD4(+) T lymphocytes within the CNS in established EAE. We report in these studies that the numbers of CD4(+) T lymphocytes in the CNS of EAE mice are decreased following treatment with OGF for five days but not LDN. However, modulation of the OGF-OGFr axis did not result in changes to CD4(+) Th effector cell responses in the CNS of EAE mice. © 2016 by the Society for Experimental Biology and Medicine.

Th17 cell cytokine secretion profile in host defense and autoimmunity.

PubMed

Graeber, Kristen E; Olsen, Nancy J

2012-02-01

The goal of this review is to examine the effector functions of Th17 cells in host defense and autoimmunity. Published literature on Th17 cells was reviewed with a focus on the secreted products that mediate effector activities of these cells. Th17 cells secrete an array of cytokines that contribute to host defense and that bridge the innate and adaptive arms of the immune response. When this subset of T cells is dysregulated, autoimmune phenomena develop that contribute to the manifestations of many autoimmune diseases. Th17 cells are positioned at a crossroads between innate and adaptive immunity and provide mediators that are essential for host defense. Current interest in harnessing this system for treatment of autoimmune disease will be challenged by the need to avoid abrogating these many protective functions.

Transcriptional Regulation of Th17 Cell Differentiation

PubMed Central

Ivanov, Ivaylo I.; Zhou, Liang; Littman, Dan R.

2009-01-01

The paradigm of effector T helper cell differentiation into either Th1 or Th2 lineages has been profoundly shaken by the discovery of T cells that secrete IL-17 and other inflammatory cytokines. This subset, referred to as Th17, is centrally involved in autoimmune disease and is important in host defense at mucosal surfaces. In mouse, a series of cytokines, including IL-6, IL-21, IL-23, and TGF-β, function sequentially or synergistically to induce the Th17 lineage. Other cytokines, including IL-2, IL-4, IFNγ, and IL-27, inhibit differentiation of this lineage. Here we review how the nuclear orphan receptor RORγt functions to coordinate the diverse cytokine-induced signals and thus control Th17 cell differentiation. PMID:18053739

Immune Senescence Factors Associated with the Immunogenicity of a Live Attenuated Zoster Vaccine (ZV) in Older Adults

PubMed Central

Weinberg, Adriana; Schamder, Kenneth; Johnson, Michael; Popmihajlov, Zoran; Tovar-Salazar, Adriana; Caldas, Yupanqui; Pang, Lei; Cho, Alice; Levin, Myron

2017-01-01

Abstract Background ZV confers protection against herpes zoster by increasing the cell-mediated immunity (CMI) to varicella-zoster virus (VZV). ZV immunogenicity and protection decrease with increasing age. We investigated effects of age and immune senescence on ZV immunogenicity. Methods 399 adults ≥50 years had VZV T-cell helper 1 (Th1) CMI measured by ex vivo VZV-stimulated IL2/IFNg ELISPOT and blood T-cell nonspecific immune senescence by flow cytometric characterization of FOXP3, CD25, IL10, TGFb, PD1, CD28, CD57 and CD31 expression before and at 1, 6 and 52 weeks after ZV. In a subset of 95 vaccinees, VZV-stimulated T cell expression of CD107, Granzyme B, FOXP3, CD25, IL10, TGFb, CD39 and PD1 were also measured. Multivariate regression analysis was used to identify independent effects of age and immune senescence on VZV Th1 CMI (P < 0.025). Results IL2+ and IL2+IFNg+ Th1 memory VZV CMI peaked at 6 weeks after ZV and remained elevated at 1 year. Effectors, including VZV-specific IFNg+ Th1, and CD8+CD107+% and CD4+/CD8+Granzyme B+% cytotoxic T lymphocytes (CTL), peaked at 1 week, but only the IFNg+ Th1 effectors remained elevated at 1 year. There was also a transient increase in blood CD8+PD1+% exhausted T cells 1 week after ZV. Independent positive effects on peak memory Th1 VZV CMI included the baseline CMI and negative effects included blood CD4+FOXP3+% T regulatory (Treg) and CD8+PD1+% T exhausted cells. Independent positive effects on peak effector Th1 VZV CMI included baseline CMI and negative effects included blood CD8+CD25+FOXP3+% Treg. Age did not have an independent effect on peak CMI. Independent positive effects on persistent (1 year) memory Th1 included baseline CMI and negative effects included age, blood CD4+FOXP3+% Treg and CD8+PD1+% T exhausted cells. Persistent effector Th1 CMI was negatively affected by age only. Conclusion ZV generated VZV-specific Th1 and CTL responses. The early increase of CD8+ exhausted T cells in blood suggested that CTL responses to the vaccine virus may be compromised by immune senescence. The negative of age on VZV Th1 CMI was fully mediated by immune senescence at peak response, but age had a negative effect on CMI persistence that was independent from the markers of immune senescence included in this study. Disclosures A. Weinberg, merck: Grant Investigator, Research grant K. Schamder, merck: Grant Investigator, Research grant Z. Popmihajlov, Merck & Co., Inc.: Employee and Shareholder, Salary L. Pang, Merck: Employee and Shareholder, Salary M. Levin, merck: Grant Investigator and Scientific Advisor, Consulting fee and Research grant

Helminth immunoregulation: The role of parasite secreted proteins in modulating host immunity

PubMed Central

Hewitson, James P.; Grainger, John R.; Maizels, Rick M.

2009-01-01

Helminths are masterful immunoregulators. A characteristic feature of helminth infection is a Th2-dominated immune response, but stimulation of immunoregulatory cell populations, such as regulatory T cells and alternatively activated macrophages, is equally common. Typically, Th1/17 immunity is blocked and productive effector responses are muted, allowing survival of the parasite in a “modified Th2” environment. Drug treatment to clear the worms reverses the immunoregulatory effects, indicating that a state of active suppression is maintained by the parasite. Hence, research has focussed on “excretory–secretory” products released by live parasites, which can interfere with every aspect of host immunity from initial recognition to end-stage effector mechanisms. In this review, we survey our knowledge of helminth secreted molecules, and summarise current understanding of the growing number of individual helminth mediators that have been shown to target key receptors or pathways in the mammalian immune system. PMID:19406170

In vitro generated Th17 cells support the expansion and phenotypic stability of CD4(+)Foxp3(+) regulatory T cells in vivo.

PubMed

Zhou, Qiong; Hu, Ya; Howard, O M Zack; Oppenheim, Joost J; Chen, Xin

2014-01-01

CD4(+) T cells stimulate immune responses through distinct patterns of cytokine produced by Th1, Th2 or Th17 cells, or inhibit immune responses through Foxp3-expressing regulatory T cells (Tregs). Paradoxically, effector T cells were recently shown to activate Tregs, however, it remains unclear which Th subset is responsible for this effect. In this study, we found that Th17 cells expressed the highest levels of TNF among in vitro generated Th subsets, and most potently promoted expansion and stabilized Foxp3 expression by Tregs when co-transferred into Rag1(-/-) mice. Both TNF and IL-2 produced by Th17 cells contributed to this effect. The stimulatory effect of Th17 cells on Tregs was largely abolished when co-transferred with TNFR2-deficient Tregs. Furthermore, Tregs deficient in TNFR2 also supported a much lower production of IL-17A and TNF expression by co-transferred Th17 cells. Thus, our data indicate that the TNF-TNFR2 pathway plays a crucial role in the reciprocal stimulatory effect of Th17 cells and Tregs. This bidirectional interaction should be taken into account when designing therapy targeting Th17 cells, Tregs, TNF and TNFR2. Copyright © 2013 Elsevier Ltd. All rights reserved.

Systems Modeling of Molecular Mechanisms Controlling Cytokine-driven CD4+ T Cell Differentiation and Phenotype Plasticity

PubMed Central

Carbo, Adria; Hontecillas, Raquel; Kronsteiner, Barbara; Viladomiu, Monica; Pedragosa, Mireia; Lu, Pinyi; Philipson, Casandra W.; Hoops, Stefan; Marathe, Madhav; Eubank, Stephen; Bisset, Keith; Wendelsdorf, Katherine; Jarrah, Abdul; Mei, Yongguo; Bassaganya-Riera, Josep

2013-01-01

Differentiation of CD4+ T cells into effector or regulatory phenotypes is tightly controlled by the cytokine milieu, complex intracellular signaling networks and numerous transcriptional regulators. We combined experimental approaches and computational modeling to investigate the mechanisms controlling differentiation and plasticity of CD4+ T cells in the gut of mice. Our computational model encompasses the major intracellular pathways involved in CD4+ T cell differentiation into T helper 1 (Th1), Th2, Th17 and induced regulatory T cells (iTreg). Our modeling efforts predicted a critical role for peroxisome proliferator-activated receptor gamma (PPARγ) in modulating plasticity between Th17 and iTreg cells. PPARγ regulates differentiation, activation and cytokine production, thereby controlling the induction of effector and regulatory responses, and is a promising therapeutic target for dysregulated immune responses and inflammation. Our modeling efforts predict that following PPARγ activation, Th17 cells undergo phenotype switch and become iTreg cells. This prediction was validated by results of adoptive transfer studies showing an increase of colonic iTreg and a decrease of Th17 cells in the gut mucosa of mice with colitis following pharmacological activation of PPARγ. Deletion of PPARγ in CD4+ T cells impaired mucosal iTreg and enhanced colitogenic Th17 responses in mice with CD4+ T cell-induced colitis. Thus, for the first time we provide novel molecular evidence in vivo demonstrating that PPARγ in addition to regulating CD4+ T cell differentiation also plays a major role controlling Th17 and iTreg plasticity in the gut mucosa. PMID:23592971

Modulation of human Th17 cell responses through complement receptor 3 (CD11 b/CD18) ligation on monocyte-derived dendritic cells.

PubMed

Nowatzky, Johannes; Manches, Olivier; Khan, Shaukat Ali; Godefroy, Emmanuelle; Bhardwaj, Nina

2018-06-13

Apoptotic cell receptors contribute to the induction of tolerance by modulating dendritic cell function following the uptake of apoptotic cells or microparticles. Dendritic cells that have bound or ingested apoptotic cells produce only low amounts of pro-inflammatory cytokines and fail to prime effector T cell responses. Specifically, ligation of the apoptotic cell receptor CR3 (CD11 b/CD18) on human monocyte-derived dendritic cells (moDC) down-modates proinflammatory cytokine secretion, but the consequences for human Th17 cell homeostasis and effector responses remain unknown. Here, we aimed to establish whether CD11b-ligated moDC modulate Th17 cell effector reponses to assess their potential for future use in moDC-based suppressive immunotherapy. We generated a bead-based surrogate system to target CD11b on monocyte-derived human dendritic cells and examined the effects of CD11b ligation on Th17-skewing cytokine secretion, priming, expansion and functional plasticity in DC/T cell co-culture systems at the poly- and monoclonal level. We show that Th17 cell expansion within the human memory CD4 + T cell compartment was efficiently constricted by targeting the CD11b receptor on moDC. This tolerogenic capacity was primarily dependent on cytokine skewing. Furthermore, ligation of CD11b on healthy homozygous carriers of the rs11143679 (ITGAM) variant - a strong genetic susceptibility marker for human systemic lupus erythematosus - also down-modulated the secretion of Th17-skewing cytokines. Overall, our findings underline the potential of targeted CD11b ligation on human dendritic cells for the engineering of suppressive immunotherapy for Th17-related autoimmune disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

Major role for CD8 T cells in the protection against Toxoplasma gondii following dendritic cell vaccination.

PubMed

Guiton, R; Zagani, R; Dimier-Poisson, I

2009-10-01

Toxoplasma gondii is the causative agent of toxoplasmosis, a worldwide zoonosis for which an effective vaccine is needed. Vaccination with pulsed dendritic cells is very efficient but their use in a vaccination protocol is unconceivable. Nevertheless, unravelling the induced effector mechanisms is crucial to design new vaccine strategies. We vaccinated CBA/J mice with parasite extract-pulsed dendritic cells, challenged them with T. gondii cysts and carried out in vivo depletion of CD4(+) or CD8(+) T lymphocytes to study the subsequent cellular immune response and protective mechanisms. CD4(+) lymphocytes were poorly implicated either in spleen and mesenteric lymph node (MLN) cytokine secretion or in mice protection. By contrast, the increasing number of intracerebral cysts and depletion of CD8(+) cells were strongly correlated, revealing a prominent role for CD8(+) lymphocytes in the protection of mice. Splenic CD8(+) lymphocytes induce a strong Th1 response controlled by a Th2 response whereas CD8(+) cells from MLNs inhibit both Th1 and Th2 responses. CD8(+) cells are the main effectors following dendritic cell vaccination and Toxoplasma infection while CD4(+) T cells only play a minor role. This contrasts with T. gondii infection which elicits the generation of CD4(+) and CD8(+) T cells that provide protective immunity.

Interleukin-4 production by Follicular Helper T cells requires the conserved Il4 enhancer HS V

PubMed Central

Vijayanand, Pandurangan; Seumois, Grégory; Simpson, Laura J.; Abdul-Wajid, Sarah; Baumjohann, Dirk; Panduro, Marisella; Huang, Xiaozhu; Interlandi, Jeneen; Djuretic, Ivana M.; Brown, Daniel R.; Sharpe, Arlene H.; Rao, Anjana; Ansel, K. Mark

2012-01-01

SUMMARY Follicular helper T cells (Tfh cells) are the major producers of interleukin-4 (IL-4) in secondary lymphoid organs where humoral immune responses develop. Il4 regulation in Tfh cells appears distinct from the classical T helper 2 (Th2) cell pathway, but the underlying molecular mechanisms remain largely unknown. We found that HS V (also known as CNS2), a 3’ enhancer in the Il4 locus, is essential for IL-4 production by Tfh cells. Mice lacking HS V display marked defects in Th2 humoral immune responses, as evidenced by abrogated IgE and sharply reduced IgG1 production in vivo. In contrast, effector Th2 cells that are involved in tissue responses were far less dependent on HS V. HS V facilitated removal of repressive chromatin marks during Th2 and Tfh cell differentiation, and increased accessibility of the Il4 promoter. Thus Tfh and Th2 cells utilize distinct but overlapping molecular mechanisms to regulate Il4, a finding with important implications for understanding the molecular basis of Th2 mediated allergic diseases. PMID:22326582

Chronic Dry Eye Disease is Principally Mediated by Effector Memory Th17 Cells

PubMed Central

Chen, Yihe; Chauhan, Sunil K.; Lee, Hyun Soo; Saban, Daniel R.; Dana, Reza

2013-01-01

Recent experimental and clinical data suggest that there is a link between dry eye disease (DED) and T cell-mediated immunity. However, whether these immune responses are a consequence or cause of ocular surface inflammation remains to be determined. Thus far, only models of acute DED have been used to derive experimental data. This is in contrast to clinical DED which usually presents as a chronic disease. In the present study, using a murine model of chronic DED, it was established that the chronic phase of the disease is accompanied by Th17 responses at the ocular surface, and that a significant memory T cell population can be recovered from chronic DED. This memory response is predominantly mediated by Th17 cells. Moreover, adoptive transfer of this memory T cell population was shown to induce more severe and rapidly progressing DED than did the adoptive transfer of its effector or naïve counterparts. Not only do these results clearly demonstrate that effector memory Th17 cells are primarily responsible for maintaining the chronic and relapsing course of DED, but they also highlight a potentially novel therapeutic strategy for targeting memory immune responses in patients with DED. PMID:23571503

B cell function in the immune response to helminths

PubMed Central

Harris, Nicola

2010-01-01

Similar T helper (Th)2-type immune responses are generated against different helminths parasites, but the mechanisms that initiate Th2 immunity, and the specific immune components that mediate protection against these parasites, can vary greatly. B cells are increasingly recognized as important during the Th2-type immune response to helminths, and B cell activation might be a target for effective vaccine development. Antibody production is a function of B cells during helminth infection and understanding how polyclonal and antigen-specific antibodies contribute should provide important insights into how protective immunity develops. In addition, B cells might also contribute to the host response against helminths through antibody-independent functions including, antigen-presentation, as well as regulatory and effector activity. In this review, we examine the role of B cells during Th2-type immune response to these multicellular parasites. PMID:21159556

CD38-NAD+Axis Regulates Immunotherapeutic Anti-Tumor T Cell Response.

PubMed

Chatterjee, Shilpak; Daenthanasanmak, Anusara; Chakraborty, Paramita; Wyatt, Megan W; Dhar, Payal; Selvam, Shanmugam Panneer; Fu, Jianing; Zhang, Jinyu; Nguyen, Hung; Kang, Inhong; Toth, Kyle; Al-Homrani, Mazen; Husain, Mahvash; Beeson, Gyda; Ball, Lauren; Helke, Kristi; Husain, Shahid; Garrett-Mayer, Elizabeth; Hardiman, Gary; Mehrotra, Meenal; Nishimura, Michael I; Beeson, Craig C; Bupp, Melanie Gubbels; Wu, Jennifer; Ogretmen, Besim; Paulos, Chrystal M; Rathmell, Jeffery; Yu, Xue-Zhong; Mehrotra, Shikhar

2018-01-09

Heightened effector function and prolonged persistence, the key attributes of Th1 and Th17 cells, respectively, are key features of potent anti-tumor T cells. Here, we established ex vivo culture conditions to generate hybrid Th1/17 cells, which persisted long-term in vivo while maintaining their effector function. Using transcriptomics and metabolic profiling approaches, we showed that the enhanced anti-tumor property of Th1/17 cells was dependent on the increased NAD + -dependent activity of the histone deacetylase Sirt1. Pharmacological or genetic inhibition of Sirt1 activity impaired the anti-tumor potential of Th1/17 cells. Importantly, T cells with reduced surface expression of the NADase CD38 exhibited intrinsically higher NAD + , enhanced oxidative phosphorylation, higher glutaminolysis, and altered mitochondrial dynamics that vastly improved tumor control. Lastly, blocking CD38 expression improved tumor control even when using Th0 anti-tumor T cells. Thus, strategies targeting the CD38-NAD + axis could increase the efficacy of anti-tumor adoptive T cell therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Stable T-bet(+)GATA-3(+) Th1/Th2 hybrid cells arise in vivo, can develop directly from naive precursors, and limit immunopathologic inflammation.

PubMed

Peine, Michael; Rausch, Sebastian; Helmstetter, Caroline; Fröhlich, Anja; Hegazy, Ahmed N; Kühl, Anja A; Grevelding, Christoph G; Höfer, Thomas; Hartmann, Susanne; Löhning, Max

2013-01-01

Differentiated T helper (Th) cell lineages are thought to emerge from alternative cell fate decisions. However, recent studies indicated that differentiated Th cells can adopt mixed phenotypes during secondary immunological challenges. Here we show that natural primary immune responses against parasites generate bifunctional Th1 and Th2 hybrid cells that co-express the lineage-specifying transcription factors T-bet and GATA-3 and co-produce Th1 and Th2 cytokines. The integration of Th1-promoting interferon (IFN)-γ and interleukin (IL)-12 signals together with Th2-favoring IL-4 signals commits naive Th cells directly and homogeneously to the hybrid Th1/2 phenotype. Specifically, IFN-γ signals are essential for T-bet(+)GATA-3(+) cells to develop in vitro and in vivo by breaking the dominance of IL-4 over IL-12 signals. The hybrid Th1/2 phenotype is stably maintained in memory cells in vivo for months. It resists reprogramming into classic Th1 or Th2 cells by Th1- or Th2-promoting stimuli, which rather induce quantitative modulations of the combined Th1 and Th2 programs without abolishing either. The hybrid phenotype is associated with intermediate manifestations of both Th1 and Th2 cell properties. Consistently, hybrid Th1/2 cells support inflammatory type-1 and type-2 immune responses but cause less immunopathology than Th1 and Th2 cells, respectively. Thus, we propose the self-limitation of effector T cells based on the stable cell-intrinsic balance of two opposing differentiation programs as a novel concept of how the immune system can prevent excessive inflammation.

Mycobacterium bovis BCG mycobacteria--new application.

PubMed

Kowalewicz-Kulbat, Magdalena; Pestel, Joël; Biet, Franck; Locht, Camille; Tonnel, André-Bernard; Druszczyńska, Magdalena; Rudnicka, Wiesława

2006-01-01

The polarized response of T helper-2 (Th2) lymphocytes to an allergen is considered to be the main cause of the pathogenesis of asthma. In this study, we asked a question whether M. bovis BCG mycobacteria which are known for the preferential stimulation of T helper-1 (Th1) immunity, diminish the effector functions of Th2 cells from allergic patients upon stimulation with a common house dust mite Der p-1 allergen. Our results allow a positive answer to this question. We demonstrate that BCG modulates the dendritic cell-dependent allergen presentation process and switches naive T lymphocytes towards an anti-allergic Th1 profile.

Interleukin-21-Producing CD4(+) T Cells Promote Type 2 Immunity to House Dust Mites.

PubMed

Coquet, Jonathan M; Schuijs, Martijn J; Smyth, Mark J; Deswarte, Kim; Beyaert, Rudi; Braun, Harald; Boon, Louis; Karlsson Hedestam, Gunilla B; Nutt, Steven L; Hammad, Hamida; Lambrecht, Bart N

2015-08-18

Asthma is a T helper 2 (Th2)-cell-mediated disease; however, recent findings implicate Th17 and innate lymphoid cells also in regulating airway inflammation. Herein, we have demonstrated profound interleukin-21 (IL-21) production after house dust mite (HDM)-driven asthma by using T cell receptor (TCR) transgenic mice reactive to Dermatophagoides pteronyssinus 1 and an IL-21GFP reporter mouse. IL-21-producing cells in the mediastinal lymph node (mLN) bore characteristics of T follicular helper (Tfh) cells, whereas IL-21(+) cells in the lung did not express CXCR5 (a chemokine receptor expressed by Tfh cells) and were distinct from effector Th2 or Th17 cells. Il21r(-/-) mice developed reduced type 2 responses and the IL-21 receptor (IL-21R) enhanced Th2 cell function in a cell-intrinsic manner. Finally, administration of recombinant IL-21 and IL-25 synergistically promoted airway eosinophilia primarily via effects on CD4(+) lymphocytes. This highlights an important Th2-cell-amplifying function of IL-21-producing CD4(+) T cells in allergic airway inflammation. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunomodulation: the future cure for allergic diseases.

PubMed

Tsitoura, Daphne C; Tassios, Yannis

2006-11-01

Allergies are the result of aberrant immune reactivity against common innocuous environmental proteins (allergens). A pivotal component of allergic pathogenesis is the generation of allergen-specific Th cells with an effector phenotype. These Th cells activate a complex immune cascade that triggers the release of potent mediators and enhances the mobilization of several inflammatory cells types, which in turn elicit the acute allergic reactions and promote the development of chronic inflammation. The current therapies for allergic diseases focus primarily on pharmacological control of symptoms and suppression of inflammation. This approach is beneficial, but not curative, since the underlying immune pathology is not inhibited. In an attempt to develop more effective therapeutic strategies, the scientific interest has been directed toward methods down-modulating the immune mechanisms that initiate and maintain the allergic cascade. Today, the only widely used disease-modifying form of allergy treatment is the specific immunotherapy with allergen extracts. More recently the use of anti-IgE has been approved for patients with allergic asthma. Other immunomodulatory methods being currently explored are the administration of microbial adjuvants that inhibit Th2 reactivity and the design of molecules that interrupt the activity of key allergic cytokines, chemokines, or other Th2 effector mediators.

Intervention of PKC-θ as an immunosuppressive regimen

PubMed Central

Sun, Zuoming

2012-01-01

PKC-θ is selectively enriched in T cells and specifically translocates to immunological synapse where it mediates critical T cell receptor signals required for T cell activation, differentiation, and survival. T cells deficient in PKC-θ are defective in their ability to differentiate into inflammatory effector cells that mediate actual immune responses whereas, their differentiation into regulatory T cells (Treg) that inhibits the inflammatory T cells is enhanced. Therefore, the manipulation of PKC-θ activity can shift the ratio between inflammatory effector T cells and inhibitory Tregs, to control T cell-mediated immune responses that are responsible for autoimmunity and allograft rejection. Indeed, PKC-θ-deficient mice are resistant to the development of several Th2 and Th17-dependent autoimmune diseases and are defective in mounting alloimmune responses required for rejection of transplanted allografts and graft-versus-host disease. Selective inhibition of PKC-θ is therefore considered as a potential treatment for prevention of autoimmune diseases and allograft rejection. PMID:22876242

Emerging Concepts of Adaptive Immunity in Leprosy

PubMed Central

Sadhu, Soumi; Mitra, Dipendra Kumar

2018-01-01

Leprosy is a chronic intracellular infection caused by the acid-fast bacillus, Mycobacterium leprae. The disease chiefly affects the skin, peripheral nerves, mucosa of the upper respiratory tract, and the eyes. The damage to peripheral nerves results in sensory and motor impairment with characteristic deformities and disability. Presently, the disease remains concentrated in resource-poor countries in tropical and warm temperate regions with the largest number of cases reported from India. Even though innate immunity influences the clinical manifestation of the disease, it is the components of adaptive immune system which seem to tightly correlate with the characteristic spectrum of leprosy. M. leprae-specific T cell anergy with bacillary dissemination is the defining feature of lepromatous leprosy (LL) patients in contrast to tuberculoid leprosy (TT) patients, which is characterized by strong Th1-type cell response with localized lesions. Generation of Th1/Th2-like effector cells, however, cannot wholly explain the polarized state of immunity in leprosy. A comprehensive understanding of the role of various regulatory T cells, such as Treg and natural killer T cells, in deciding the polarized state of T cell immunity is crucial. Interaction of these T cell subsets with effector T cells like Th1 (IFN-γ dominant), Th2 (interluekin-4 dominant), and Th17 (IL-17+) cells through various regulatory cytokines and molecules (programmed death-1/programmed death ligand-1) may constitute key events in dictating the state of immune polarization, thus controlling the clinical manifestation. Studying these important components of the adaptive immune system in leprosy patients is essential for better understanding of immune function, correlate(s) the immunity and mechanism(s) of its containment. PMID:29686668

Mutual antagonism of TGF-beta and Interleukin-2 in cell survival and lineage commitment of induced regulatory T cells

PubMed Central

Tischner, D; Wiegers, G J; Fiegl, H; Drach, M; Villunger, A

2012-01-01

Transforming growth factor beta (TGF-β)- and Interleukin-2 (IL-2)-mediated signaling enables the generation and expansion of induced regulatory T (iTreg) cells that carry high hopes for the treatment of chronic inflammatory and autoimmune diseases. Knowledge about factors stabilizing their lineage commitment and lifespan, however, is limited. Here, we investigated the behavior of iTreg cells, derived from apoptosis-defective mouse mutants, during activated cell autonomous cell death, triggered by cytokine-deprivation, or activation-induced cell death (AICD) after restimulation of the T-cell receptor, and compared these responses with those of effector T cells. We observed that iTreg cells were much more sensitive to IL-2-deprivation but poorly susceptible to AICD. In fact, when apoptosis was compromised, T-cell receptor (TCR)-religation resulted in methylation-independent, ERK- and PI3K/mTOR-mediated loss of Foxp3 expression, impaired suppressive capacity and effector cytokine production. Although iTreg cells prevented colitis induction they rapidly lost Foxp3-GFP expression and gained ability to produce effector cytokines thereby imposing Th1 cell fate on resident effector cells. Surprisingly, iTreg cell conversion itself was limited by TGF-β-mediated Bim/Bcl2L11-dependent apoptosis. Hence, the very same cytokine that drives the generation of iTreg cells can trigger their demise. Our results provide novel insights in iTreg cell biology that will assist optimization of iTreg-based therapy. PMID:22322859

Th9 Cells Drive Host Immunity against Gastrointestinal Worm Infection.

PubMed

Licona-Limón, Paula; Henao-Mejia, Jorge; Temann, Angela U; Gagliani, Nicola; Licona-Limón, Ileana; Ishigame, Harumichi; Hao, Liming; Herbert, De'broski R; Flavell, Richard A

2013-10-17

Type 2 inflammatory cytokines, including interleukin-4 (IL-4), IL-5, IL-9, and IL-13, drive the characteristic features of immunity against parasitic worms and allergens. Whether IL-9 serves an essential role in the initiation of host-protective responses is controversial, and the importance of IL-9- versus IL-4-producing CD4⁺ effector T cells in type 2 immunity is incompletely defined. Herein, we generated IL-9-deficient and IL-9-fluorescent reporter mice that demonstrated an essential role for this cytokine in the early type 2 immunity against Nippostrongylus brasiliensis. Whereas T helper 9 (Th9) cells and type 2 innate lymphoid cells (ILC2s) were major sources of infection-induced IL-9 production, the adoptive transfer of Th9 cells, but not Th2 cells, caused rapid worm expulsion, marked basophilia, and increased mast cell numbers in Rag2-deficient hosts. Taken together, our data show a critical and nonredundant role for Th9 cells and IL-9 in host-protective type 2 immunity against parasitic worm infection. Copyright © 2013 Elsevier Inc. All rights reserved.

Differentiation of Effector CD4 T Cell Populations*

PubMed Central

Zhu, Jinfang; Yamane, Hidehiro; Paul, William E.

2012-01-01

CD4 T cells play critical roles in mediating adaptive immunity to a variety of pathogens. They are also involved in autoimmunity, asthma, and allergic responses as well as in tumor immunity. During TCR activation in a particular cytokine milieu, naive CD4 T cells may differentiate into one of several lineages of T helper (Th) cells, including Th1, Th2, Th17, and iTreg, as defined by their pattern of cytokine production and function. In this review, we summarize the discovery, functions, and relationships among Th cells; the cytokine and signaling requirements for their development; the networks of transcription factors involved in their differentiation; the epigenetic regulation of their key cytokines and transcription factors; and human diseases involving defective CD4 T cell differentiation. PMID:20192806

Small RNA Transfection in Primary Human Th17 Cells by Next Generation Electroporation.

PubMed

Montoya, Misty M; Ansel, K Mark

2017-04-13

CD4 + T cells can differentiate into several subsets of effector T helper cells depending on the surrounding cytokine milieu. Th17 cells can be generated from naïve CD4 + T cells in vitro by activating them in the presence of the polarizing cytokines IL-1β, IL-6, IL-23, and TGFβ. Th17 cells orchestrate immunity against extracellular bacteria and fungi, but their aberrant activity has also been associated with several autoimmune and inflammatory diseases. Th17 cells are identified by the chemokine receptor CCR6 and defined by their master transcription factor, RORγt, and characteristic effector cytokine, IL-17A. Optimized culture conditions for Th17 cell differentiation facilitate mechanistic studies of human T cell biology in a controlled environment. They also provide a setting for studying the importance of specific genes and gene expression programs through RNA interference or the introduction of microRNA (miRNA) mimics or inhibitors. This protocol provides an easy to use, reproducible, and highly efficient method for transient transfection of differentiating primary human Th17 cells with small RNAs using a next generation electroporation device.

Deletion of Fibrinogen-like Protein 2 (FGL-2), a Novel CD4+ CD25+ Treg Effector Molecule, Leads to Improved Control of Echinococcus multilocularis Infection in Mice

PubMed Central

Wang, Junhua; Vuitton, Dominique A.; Müller, Norbert; Hemphill, Andrew; Spiliotis, Markus; Blagosklonov, Oleg; Grandgirard, Denis; Leib, Stephen L.; Shalev, Itay; Levy, Gary; Lu, Xiaomei; Lin, Renyong; Wen, Hao; Gottstein, Bruno

2015-01-01

Background The growth potential of the tumor-like Echinococcus multilocularis metacestode (causing alveolar echinococcosis, AE) is directly linked to the nature/function of the periparasitic host immune-mediated processes. We previously showed that Fibrinogen-like-protein 2 (FGL2), a novel CD4+CD25+ Treg effector molecule, was over-expressed in the liver of mice experimentally infected with E. multilocularis. However, little is known about its contribution to the control of this chronic helminth infection. Methods/Findings Key parameters for infection outcome in E. multilocularis-infected fgl2-/- (AE-fgl2-/-) and wild type (AE-WT) mice at 1 and 4 month(s) post-infection were (i) parasite load (i. e. wet weight of parasitic metacestode tissue), and (ii) parasite cell proliferation as assessed by determining E. multilocularis 14-3-3 gene expression levels. Serum FGL2 levels were measured by ELISA. Spleen cells cultured with ConA for 48h or with E. multilocularis Vesicle Fluid (VF) for 96h were analyzed ex-vivo and in-vitro. In addition, spleen cells from non-infected WT mice were cultured with rFGL2/anti-FGL2 or rIL-17A/anti-IL-17A for further functional studies. For Treg-immune-suppression-assays, purified CD4+CD25+ Treg suspensions were incubated with CD4+ effector T cells in the presence of ConA and irradiated spleen cells as APCs. Flow cytometry and qRT-PCR were used to assess Treg, Th17-, Th1-, Th2-type immune responses and maturation of dendritic cells. We showed that AE-fgl2-/- mice exhibited (as compared to AE-WT-animals) (a) a significantly lower parasite load with reduced proliferation activity, (b) an increased T cell proliferative response to ConA, (c) reduced Treg numbers and function, and (d) a persistent capacity of Th1 polarization and DC maturation. Conclusions FGL2 appears as one of the key players in immune regulatory processes favoring metacestode survival by promoting Treg cell activity and IL-17A production that contributes to FGL2-regulation. Prospectively, targeting FGL2 could be an option to develop an immunotherapy against AE and other chronic parasitic diseases. PMID:25955764

Innate immunity and effector and regulatory mechanisms involved in allergic contact dermatitis.

PubMed

Silvestre, Marilene Chaves; Sato, Maria Notomi; Reis, Vitor Manoel Silva Dos

2018-03-01

Skin's innate immunity is the initial activator of immune response mechanisms, influencing the development of adaptive immunity. Some contact allergens are detected by Toll-like receptors (TLRs) and inflammasome NLR3. Keratinocytes participate in innate immunity and, in addition to functioning as an anatomical barrier, secrete cytokines, such as TNF, IL-1β, and IL-18, contributing to the development of Allergic Contact Dermatitis. Dendritic cells recognize and process antigenic peptides into T cells. Neutrophils cause pro-inflammatory reactions, mast cells induce migration/maturation of skin DCs, the natural killer cells have natural cytotoxic capacity, the γδ T cells favor contact with hapten during the sensitization phase, and the innate lymphoid cells act in the early stages by secreting cytokines, as well as act in inflammation and tissue homeostasis. The antigen-specific inflammation is mediated by T cells, and each subtype of T cells (Th1/Tc1, Th2/Tc2, and Th17/Tc17) activates resident skin cells, thus contributing to inflammation. Skin's regulatory T cells have a strong ability to inhibit the proliferation of hapten-specific T cells, acting at the end of the Allergic Contact Dermatitis response and in the control of systemic immune responses. In this review, we report how cutaneous innate immunity is the first line of defense and focus its role in the activation of the adaptive immune response, with effector response induction and its regulation.

IgG4 subclass antibodies impair antitumor immunity in melanoma

PubMed Central

Karagiannis, Panagiotis; Gilbert, Amy E.; Josephs, Debra H.; Ali, Niwa; Dodev, Tihomir; Saul, Louise; Correa, Isabel; Roberts, Luke; Beddowes, Emma; Koers, Alexander; Hobbs, Carl; Ferreira, Silvia; Geh, Jenny L.C.; Healy, Ciaran; Harries, Mark; Acland, Katharine M.; Blower, Philip J.; Mitchell, Tracey; Fear, David J.; Spicer, James F.; Lacy, Katie E.; Nestle, Frank O.; Karagiannis, Sophia N.

2013-01-01

Host-induced antibodies and their contributions to cancer inflammation are largely unexplored. IgG4 subclass antibodies are present in IL-10–driven Th2 immune responses in some inflammatory conditions. Since Th2-biased inflammation is a hallmark of tumor microenvironments, we investigated the presence and functional implications of IgG4 in malignant melanoma. Consistent with Th2 inflammation, CD22+ B cells and IgG4+-infiltrating cells accumulated in tumors, and IL-10, IL-4, and tumor-reactive IgG4 were expressed in situ. When compared with B cells from patient lymph nodes and blood, tumor-associated B cells were polarized to produce IgG4. Secreted B cells increased VEGF and IgG4, and tumor cells enhanced IL-10 secretion in cocultures. Unlike IgG1, an engineered tumor antigen-specific IgG4 was ineffective in triggering effector cell–mediated tumor killing in vitro. Antigen-specific and nonspecific IgG4 inhibited IgG1-mediated tumoricidal functions. IgG4 blockade was mediated through reduction of FcγRI activation. Additionally, IgG4 significantly impaired the potency of tumoricidal IgG1 in a human melanoma xenograft mouse model. Furthermore, serum IgG4 was inversely correlated with patient survival. These findings suggest that IgG4 promoted by tumor-induced Th2-biased inflammation may restrict effector cell functions against tumors, providing a previously unexplored aspect of tumor-induced immune escape and a basis for biomarker development and patient-specific therapeutic approaches. PMID:23454746

Lung effector memory and activated CD4+ T cells display enhanced proliferation in surfactant protein A-deficient mice during allergen-mediated inflammation.

PubMed

Pastva, Amy M; Mukherjee, Sambuddho; Giamberardino, Charles; Hsia, Bethany; Lo, Bernice; Sempowski, Gregory D; Wright, Jo Rae

2011-03-01

Although many studies have shown that pulmonary surfactant protein (SP)-A functions in innate immunity, fewer studies have addressed its role in adaptive immunity and allergic hypersensitivity. We hypothesized that SP-A modulates the phenotype and prevalence of dendritic cells (DCs) and CD4(+) T cells to inhibit Th2-associated inflammatory indices associated with allergen-induced inflammation. In an OVA model of allergic hypersensitivity, SP-A(-/-) mice had greater eosinophilia, Th2-associated cytokine levels, and IgE levels compared with wild-type counterparts. Although both OVA-exposed groups had similar proportions of CD86(+) DCs and Foxp3(+) T regulatory cells, the SP-A(-/-) mice had elevated proportions of CD4(+) activated and effector memory T cells in their lungs compared with wild-type mice. Ex vivo recall stimulation of CD4(+) T cell pools demonstrated that cells from the SP-A(-/-) OVA mice had the greatest proliferative and IL-4-producing capacity, and this capability was attenuated with exogenous SP-A treatment. Additionally, tracking proliferation in vivo demonstrated that CD4(+) activated and effector memory T cells expanded to the greatest extent in the lungs of SP-A(-/-) OVA mice. Taken together, our data suggested that SP-A influences the prevalence, types, and functions of CD4(+) T cells in the lungs during allergic inflammation and that SP deficiency modifies the severity of inflammation in allergic hypersensitivity conditions like asthma.

Virus Infection Stages and Distinct Th1 or Th17/Th22 T-Cell Responses in Malaria/SHIV Coinfection Correlate with Different Outcomes of Disease

PubMed Central

Ryan-Payseur, Bridgett; Ali, Zahida; Huang, Dan; Chen, Crystal Y.; Yan, Lin; Wang, Richard C.; Collins, William E.; Wang, Yunqi

2011-01-01

Background. Malaria and AIDS represent 2 leading causes of death from infectious diseases worldwide, and their high geographic overlap means coinfection is prevalent. It remains unknown whether distinct immune responses during coinfection with malaria and human immunodeficiency virus (HIV) affect clinical outcomes. Methods. We tested this hypothesis by employing macaque models of coinfection with malaria and simian-human immunodeficiency virus (SHIV). Results. Plasmodium fragile malaria coinfection of acutely SHIV-infected macaques induced hyperimmune activation and remarkable expansion of CD4+ and CD8+ T effector cells de novo producing interferon γ or tumor necrosis factor α. Malaria-driven cellular hyperactivation/expansion and high-level Th1-cytokines enhanced SHIV disease characterized by increasing CD4+ T-cell depletion, profound lymphoid depletion or destruction, and even necrosis in lymph nodes and spleens. Importantly, malaria/SHIV-mediated depletion, destruction, and necrosis in lymphoid tissues led to bursting parasite replication and fatal virus-associated malaria. Surprisingly, chronically SHIV-infected macaques without AIDS employed different defense mechanisms during malaria coinfection, and mounted unique ∼200-fold expansion of interleukin 17+/interleukin 22+ T effectors with profound Th1 suppression. Such remarkable expansion of Th17/Th22 cells and inhibition of Th1 response coincided with development of immunity against fatal virus-associated malaria without accelerating SHIV disease. Conclusions. These novel findings suggest that virus infection status and selected Th1 or Th17/Th22 responses after malaria/AIDS-virus coinfection correlate with distinct outcomes of virus infection and malaria. PMID:21921207

Epitope diversification driven by non-tumor epitope-specific Th1 and Th17 mediates potent antitumor reactivity.

PubMed

Ichikawa, Kosuke; Kagamu, Hiroshi; Koyama, Kenichi; Miyabayashi, Takao; Koshio, Jun; Miura, Satoru; Watanabe, Satoshi; Yoshizawa, Hirohisa; Narita, Ichiei

2012-09-21

MHC class I-restricted peptide-based vaccination therapies have been conducted to treat cancer patients, because CD8⁺ CTL can efficiently induce apoptosis of tumor cells in an MHC class I-restricted epitope-specific manner. Interestingly, clinical responders are known to demonstrate reactivity to epitopes other than those used for vaccination; however, the mechanism underlying how antitumor T cells with diverse specificity are induced is unclear. In this study, we demonstrated that dendritic cells (DCs) that engulfed apoptotic tumor cells in the presence of non-tumor MHC class II-restricted epitope peptides, OVA(323-339), efficiently presented tumor-associated antigens upon effector-dominant CD4⁺ T cell balance against regulatory T cells (Treg) for the OVA(323-339) epitope. Th1 and Th17 induced tumor-associated antigens presentation of DC, while Th2 ameliorated tumor-antigen presentation for CD8⁺ T cells. Blocking experiments with anti-IL-23p19 antibody and anti-IL-23 receptor indicated that an autocrine mechanism of IL-23 likely mediated the diverted tumor-associated antigens presentation of DC. Tumor-associated antigens presentation of DC induced by OVA(323-339) epitope-specific CD4⁺ T cells resulted in facilitated antitumor immunity in both priming and effector phase in vivo. Notably, this immunotherapy did not require pretreatment to reduce Treg induced by tumor. This strategy may have clinical implications for designing effective antitumor immunotherapies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Developmental acquisition of regulomes underlies innate lymphoid cell functionality

USDA-ARS?s Scientific Manuscript database

Innate lymphoid cells (ILCs) play key roles in host defense, barrier integrity, and homeostasis, and they mirror adaptive CD4+ T helper (Th) cell subtypes in both usages of effector molecules and ·transcription factors. To better understand ILC subsets and their relationship with Th cells, we measur...

Th1-like Plasmodium-Specific Memory CD4+ T Cells Support Humoral Immunity.

PubMed

Zander, Ryan A; Vijay, Rahul; Pack, Angela D; Guthmiller, Jenna J; Graham, Amy C; Lindner, Scott E; Vaughan, Ashley M; Kappe, Stefan H I; Butler, Noah S

2017-11-14

Effector T cells exhibiting features of either T helper 1 (Th1) or T follicular helper (Tfh) populations are essential to control experimental Plasmodium infection and are believed to be critical for resistance to clinical malaria. To determine whether Plasmodium-specific Th1- and Tfh-like effector cells generate memory populations that contribute to protection, we developed transgenic parasites that enable high-resolution study of anti-malarial memory CD4 T cells in experimental models. We found that populations of both Th1- and Tfh-like Plasmodium-specific memory CD4 T cells persist. Unexpectedly, Th1-like memory cells exhibit phenotypic and functional features of Tfh cells during recall and provide potent B cell help and protection following transfer, characteristics that are enhanced following ligation of the T cell co-stimulatory receptor OX40. Our findings delineate critical functional attributes of Plasmodium-specific memory CD4 T cells and identify a host-specific factor that can be targeted to improve resolution of acute malaria and provide durable, long-term protection against Plasmodium parasite re-exposure. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Prostaglandin E2 inhibits Tr1 cell differentiation through suppression of c-Maf

PubMed Central

Hooper, Kirsten Mary; Kong, Weimin

2017-01-01

Prostaglandin E2 (PGE2), a major lipid mediator abundant at inflammatory sites, acts as a proinflammatory agent in models of inflammatory/autoimmune diseases by promoting CD4 Th1/Th17 differentiation. Regulatory T cells, including the IL-10 producing Tr1 cells counterbalance the proinflammatory activity of effector Th1/Th17 cells. Tr1 cell differentiation and function are induced by IL-27, and depend primarily on sustained expression of c-Maf in addition to AhR and Blimp-1. In agreement with the in vivo proinflammatory role of PGE2, here we report for the first time that PGE2 inhibits IL-27-induced differentiation and IL-10 production of murine CD4+CD49b+LAG-3+Foxp3- Tr1 cells. The inhibitory effect of PGE2 was mediated through EP4 receptors and induction of cAMP, leading to a significant reduction in c-Maf expression. Although PGE2 reduced IL-21 production in differentiating Tr1 cells, its inhibitory effect on Tr1 differentiation and c-Maf expression also occurred independent of IL-21 signaling. PGE2 did not affect STAT1/3 activation, AhR expression and only marginally reduced Egr-2/Blimp-1 expression. The effect of PGE2 on CD4+CD49b+LAG-3+ Tr1 differentiation was not associated with either induction of Foxp3 or IL-17 production, suggesting a lack of transdifferentiation into Foxp3+ Treg or effector Th17 cells. We recently reported that PGE2 inhibits the expression and production of IL-27 from activated conventional dendritic cells (cDC) in vivo and in vitro. The present study indicates that PGE2 also reduces murine Tr1 differentiation and function directly by acting on IL-27-differentiating Tr1 cells. Together, the ability of PGE2 to inhibit IL-27 production by cDC, and the direct inhibitory effect on Tr1 differentiation mediated through reduction in c-Maf expression, represent a new mechanistic perspective for the proinflammatory activity of PGE2. PMID:28604806

Preferential susceptibility of Th9 and Th2 CD4+ T cells to X4-tropic HIV-1 infection.

PubMed

Orlova-Fink, Nina; Chowdhury, Fatema Z; Sun, Xiaoming; Harrington, Sean; Rosenberg, Eric S; Yu, Xu G; Lichterfeld, Mathias

2017-10-23

The functional polarization of CD4 T cells determines their antimicrobial effector profile, but may also impact the susceptibility to infection with HIV-1. Here, we analyzed the susceptibility of CD4 T cells with different functional polarization to infection with X4 and R5-tropic HIV-1. CD4 T cells with a Th1, Th2, Th17, and Th9 polarization were subjected to in-vitro infection assays with X4, R5, or vesicular stomatitis virus-G protein-pseudotyped HIV-1. In addition, we sorted differentially polarized CD4 T-cell subsets from individuals treated with antiretroviral therapy and analyzed the tropism of viral env sequences. Th9-polarized CD4 T cells and, to a lesser extent, Th2-polarized CD4 T cells expressed higher surface levels of CXCR4, and are more permissive to X4-tropic infection in vitro. In contrast, Th1 and Th17 CD4 T cells exhibited stronger surface expression of CCR5, and were more susceptible to infection with R5-tropic viruses. Correspondingly, the distribution of X4-tropic viral sequences in antiretroviral therapy-treated HIV-1-infected patients was biased toward Th9/Th2 cells, whereas R5-tropic sequences were more frequently observed in Th17 cells. CD4 T-cell polarization is associated with a distinct susceptibility to X4 and R5-tropic HIV-1 infection.

CD4(+) T-cell responses to Epstein-Barr virus (EBV) latent membrane protein 1 in infectious mononucleosis and EBV-associated non-Hodgkin lymphoma: Th1 in active disease but Tr1 in remission.

PubMed

Marshall, Neil A; Culligan, Dominic J; Johnston, Peter W; Millar, Colin; Barker, Robert N; Vickers, Mark A

2007-10-01

Primary infection with Epstein-Barr virus (EBV) in childhood is usually asymptomatic, whereas infection in adolescence may result in infectious mononucleosis (IM) often followed by a fatigue syndrome. EBV latent membrane protein 1 (LMP1) is expressed in latency and in many EBV-associated tumours, including non-Hodgkin lymphoma (NHL). Given the regulatory nature of the CD4(+) T-cell response against LMP1 previously reported in healthy donors, we investigated whether patients with active EBV-driven disease can nevertheless mount effector [T-helper cell, type 1 (Th1)] anti-LMP1 responses. We therefore performed a longitudinal study of the nature of CD4(+) T-cell responses to LMP1 in four patients with IM, and five patients with NHL. In both groups, responses changed with time. During symptomatic infection or active tumour growth, responses were dominated by a Th1 effector phenotype, but switched to a regulatory interleukin-10 response upon recovery. In addition, the fine specificities of the T cells driving these responses evolved. This study showed the dynamic nature of CD4(+) T-cell responses to LMP1, and demonstrated that, although patients can mount Th1 effector responses, recovery from IM and NHL is associated with regulatory responses.

Dendritic Cells Regulate Treg-Th17 Axis in Obstructive Phase of Bile Duct Injury in Murine Biliary Atresia

PubMed Central

Tang, Shao-tao; Wang, Xin-xing; Cao, Guo-qing; Li, Shuai; Lei, Hai-yan; Zhang, Xi

2015-01-01

Several cell types are considered to be effector cells in bile duct injury in rhesus rotavirus (RRV)-induced experimental biliary atresia (BA). Here, we identified an increased T helper 17 (Th17) cell population in a BA mode. By depleting the Th17 cells, the BA symptoms (onset of jaundice, acholic stools and retarded growth) were attenuated and the survival rate was improved. Furthermore, we found that in mice with BA, the percentage of CD4+CD25highFoxp3+ T regulatory (Treg) cells decreased along with the increased percentage of Th17 cells. However, the absolute numbers of Treg and Th17 cells were both increased in liver of RRV-injected mice compared to saline-injected mice. The proportion of Th17 cells at 7 days post-infection was decreased if Treg cells isolated from normal adult mice, but not Treg cells from the livers of mice with BA, were intraperitoneally transferred on day 5 of life. In vitro experiments also showed that Treg cells from mice with BA had a diminished suppressive effect on Th17 cell generation. To determine the mechanisms, we investigated the production of cytokines in the liver. The level of IL-6, which has been shown to be abundantly secreted by activated dendritic cells (DCs), was remarkably elevated. Importantly, in a Treg/Th17 cell suppression assay, IL-6 was demonstrated to paralyze the Treg cells’ suppressive effect on Th17 cells and eventually the unrestrained increase of Th17 cells contributed to bile duct injury. In conclusion, the DC-regulated Treg-Th17 axis, probably in conjunction with other effector T cells, aggravates progressive inflammatory injury at the time of ductal obstruction. PMID:26325187

A new look at immune privilege of the eye: dual role for the vision-related molecule retinoic acid.

PubMed

Zhou, Ru; Horai, Reiko; Mattapallil, Mary J; Caspi, Rachel R

2011-10-15

The eye is an immunologically privileged and profoundly immunosuppressive environment. Early studies reported inhibition of T cell proliferation, IFN-γ production, and generation of regulatory T cells (Tregs) by aqueous humor (AH) and identified TGF-β as a critical factor. However, T cell subsets including Foxp3(+) Treg and Th17 were unknown at that time, as was the role of retinoic acid (RA) in Treg induction. Consequently, the effect of the ocular microenvironment on T cell lineage commitment and function, and the role of RA in this process, had not been explored. We now use gene-manipulated mice and highly purified T cell populations to demonstrate that AH suppresses lineage commitment and acquisition of Th1 and Th17 effector function of naive T cells, manifested as reduction of lineage-specific transcription factors and cytokines. Instead, AH promoted its massive conversion to Foxp3(+) Tregs that expressed CD25, GITR, CTLA-4, and CD103 and were functionally suppressive. TGF-β and RA were both needed and synergized for Treg conversion by AH, with TGF-β-enhancing T cell expression of RA receptor α. Newly converted Foxp3(+) Tregs were unstable, but were stabilized upon continued exposure to AH or by the DNA demethylating agent 5-aza-2'-deoxycytidine. In contrast, T cells already committed to effector function were resistant to the suppressive and Treg-inducing effects of AH. We conclude that RA in the eye plays a dual role: in vision and in immune privilege. Nevertheless, primed effector T cells are relatively insensitive to AH, helping to explain their ability to induce uveitis despite an inhibitory ocular microenvironment.

Female-specific down-regulation of tissue-PMN drives impaired Treg and amplified effector T cell responses in autoimmune dry eye disease1

PubMed Central

Gao, Yuan; Min, Kyungji; Zhang, Yibing; Su, John; Greenwood, Matthew; Gronert, Karsten

2015-01-01

Immune-driven dry eye disease primarily affects women; the cause for this sex-specific prevalence is unknown. PMN have distinct phenotypes that drive inflammation but also regulate lymphocytes and are the rate-limiting cell for generating anti-inflammatory lipoxin A4 (LXA4). Estrogen regulates the LXA4 circuit to induce delayed female-specific wound healing in the cornea. However, the role of PMN in dry eye disease remains unexplored. We discovered a LXA4-producing tissue-PMN population in the corneal limbus, lacrimal glands and cervical lymph nodes of healthy male and female mice. These tissue-PMN, unlike inflammatory-PMN, expressed a highly amplified LXA4 circuit and were sex-specifically regulated during immune-driven dry eye disease. Desiccating stress in females, unlike in males, triggered a remarkable decrease in lymph node PMN and LXA4 formation that remained depressed during dry eye disease. Depressed lymph node PMN and LXA4 in females correlated with an increase in T effector cells (TH1 and TH17), a decrease in regulatory T cells (Treg) and increased dry eye pathogenesis. Antibody depletion of tissue-PMN abrogated LXA4 formation in lymph nodes, caused a marked increase in TH1 and TH17 and decrease in Treg cells. To establish an immune regulatory role for PMN-derived LXA4 in dry eye females were treated with LXA4. LXA4 treatment markedly inhibited TH1 and TH17 and amplified Treg cells in draining lymph nodes, while reducing dry eye pathogenesis. These results identify female-specific regulation of LXA4-producing tissue-PMN as a potential key factor in aberrant T effector cell activation and initiation of immune-driven dry eye disease. PMID:26324767

Rapamycin resistant murine th9 cells have a stable in vivo phenotype and inhibit graft-versus-host reactivity.

PubMed

Mangus, Courtney W; Massey, Paul R; Fowler, Daniel H; Amarnath, Shoba

2013-01-01

The cytokine micro-environment can direct murine CD4(+) T cells towards various differentiation lineages such as Th1, Th2 and Tregs even in the presence of rapamycin, which results in T cells that mediate increased in vivo effects. Recently, a new lineage of T cells known as Th9 cells that secrete increased IL-9 have been described. However, it is not known whether Th9 differentiation occurs in the presence of rapamycin or whether adoptively transferred donor Th9 cells would augment or restrict alloreactivity after experimental bone marrow transplantation. We found that CD4(+) T cells that were co-stimulated and polarized with TGF-β and IL-4 in the presence or absence of rapamycin each yielded effector cells of Th9 phenotype that secreted increased IL-9 and expressed a transcription factor profile characteristic of both Th9 and Th2 cells (high GATA-3/low T-bet). Augmentation of T cell replete allografts with manufactured rapamycin resistant Th9 cells markedly reduced both CD4(+) and CD8(+) T cell engraftment and strongly inhibited allo-specific T cell secretion of IFN-γ. The potency of Th9 cell inhibition of alloreactivity was similar to that of rapamycin resistant Th2 cells. Importantly, rapamycin resistant Th9 cells persisted and maintained their cytokine phenotype, thereby indicating limited differentiation plasticity of the Th9 subset. As such, Th9 differentiation proceeds in the presence of rapamycin to generate a cell therapy product that maintains high IL-9 expression in vivo while inhibiting IFN-γ driven alloreactivity.

Immunological Characteristics of Colitis Associated with Anti-CTLA-4 Antibody Therapy.

PubMed

Bamias, Giorgos; Delladetsima, Ioanna; Perdiki, Marina; Siakavellas, Spyros I; Goukos, Dimitrios; Papatheodoridis, George V; Daikos, George L; Gogas, Helen

2017-08-09

Anti-CTL4-A therapy is associated with development of colitis. We characterized ipilimumab-associated colitis in nine melanoma patients (6 male, mean age: 55.3-yrs). Median value for diarrhea grade was 2, number of ipilimumab doses 2, and interval since last administration 3-wks. Endoscopic characteristics resembled inflammatory bowel disease and histology revealed predominance of plasmacytes or CD4+ T-cells. We observed significant upregulation of Th1 and Th17 effector pathways (>10-fold increase for IFN-γmRNA, >5-fold for IL-17A, p < 0.01 vs. controls). Significant elevation of FoxP3 was also detected. In conclusion, ipilimumab administration results in elevations of effector lymphocytes and pro-inflammatory mediators in the gut lamina propria.

Development of chronic allergic responses by dampening Bcl6-mediated suppressor activity in memory T helper 2 cells

PubMed Central

Ogasawara, Takashi; Hatano, Masahiko; Satake, Hisae; Ikari, Jun; Taniguchi, Toshibumi; Tsuruoka, Nobuhide; Watanabe-Takano, Haruko; Fujimura, Lisa; Sakamoto, Akemi; Hirata, Hirokuni; Sugiyama, Kumiya; Fukushima, Yasutsugu; Nakae, Susumu; Matsumoto, Kenji; Saito, Hirohisa; Fukuda, Takeshi; Kurasawa, Kazuhiro; Tatsumi, Koichiro; Tokuhisa, Takeshi

2017-01-01

Mice deficient in the transcriptional repressor B-cell CLL/lymphoma 6 (Bcl6) exhibit similar T helper 2 (TH2) immune responses as patients with allergic diseases. However, the molecular mechanisms underlying Bcl6-directed regulation of TH2 cytokine genes remain unclear. We identified multiple Bcl6/STAT binding sites (BSs) in TH2 cytokine gene loci. We found that Bcl6 is modestly associated with the BSs, and it had no significant effect on cytokine production in newly differentiated TH2 cells. Contrarily, in memory TH2 (mTH2) cells derived from adaptively transferred TH2 effectors, Bcl6 outcompeted STAT5 for binding to TH2 cytokine gene loci, particularly Interleukin4 (Il4) loci, and attenuated GATA binding protein 3 (GATA3) binding to highly conserved intron enhancer regions in mTH2 cells. Bcl6 suppressed cytokine production epigenetically in mTH2 cells to negatively tune histone acetylation at TH2 cytokine gene loci, including Il4 loci. In addition, IL-33, a pro-TH2 cytokine, diminished Bcl6’s association with loci to which GATA3 recruitment was inversely augmented, resulting in altered IL-4, but not IL-5 and IL-13, production in mTH2 cells but no altered production in newly differentiated TH2 cells. Use of a murine asthma model that generates high levels of pro-TH2 cytokines, such as IL-33, suggested that the suppressive function of Bcl6 in mTH2 cells is abolished in severe asthma. These findings indicate a role of the interaction between TH2-promoting factors and Bcl6 in promoting appropriate IL-4 production in mTH2 cells and suggest that chronic allergic diseases involve the TH2-promoting factor-mediated functional breakdown of Bcl6, resulting in allergy exacerbation. PMID:28096407

Failure of itraconazole to prevent T-helper type 2 cell immune deviation: Implications for chronic rhinosinusitis.

PubMed

Kennedy, Joshua L; Steinke, John W; Liu, Lixia; Negri, Julie; Borish, Larry; Payne, Spencer C

2016-11-01

T-helper (Th) type 2 cell inflammation is the hallmark of several disease processes, including asthma, atopic dermatitis, and some forms of chronic rhinosinusitis. Itraconazole has been used as both an antifungal and an anti-inflammatory agent, with some success in many of these diseases, in part, by altering Th2 cytokine expression by T cells. It is not known whether this merely reflects inhibition of established Th2-like cells or the inhibition of differentiation of naive T cells into Th2-like cells. To evaluate the role of itraconazole in the differentiation of naive T cells during activation. Naive CD45RA+ T cells were isolated from peripheral blood mononuclear cells from healthy volunteers. Th1 and Th2 type cells were differentiated in the presence of varying concentrations of itraconazole. After stimulation with anti-CD3 and anti-CD28 beads, carboxyfluorescein succinimidyl ester dilution was performed to evaluate proliferation and intracellular cytokine staining for interleukin (IL) 4 and interferon (IFN) gamma within proliferating T cells was measured along with enzyme-linked immunosorbent assay for secreted IL-5, IL-13, and IFN gamma. Itraconazole had no effect on proliferation of unbiased, Th1, or Th2 cells. Similarly, there was no effect of itraconazole on either intracellular cytokine staining of IL-4 and IFN gamma or secreted cytokine expression of IFN gamma, IL-5, and IL-13 in any of the cell populations. Itraconazole did not alter the ability of naive T cells to proliferate or secrete cytokines under Th1 or Th2 deviating conditions in vitro. As such, reported inhibition of Th2-like lymphocyte function by itraconazole reflected action on mature effector cells and may have underscored why antifungal treatment failed in many clinical trials of eosinophilic chronic rhinosinusitis.

Innate immunity and effector and regulatory mechanisms involved in allergic contact dermatitis*

PubMed Central

Silvestre, Marilene Chaves; Sato, Maria Notomi; dos Reis, Vitor Manoel Silva

2018-01-01

Skin's innate immunity is the initial activator of immune response mechanisms, influencing the development of adaptive immunity. Some contact allergens are detected by Toll-like receptors (TLRs) and inflammasome NLR3. Keratinocytes participate in innate immunity and, in addition to functioning as an anatomical barrier, secrete cytokines, such as TNF, IL-1β, and IL-18, contributing to the development of Allergic Contact Dermatitis. Dendritic cells recognize and process antigenic peptides into T cells. Neutrophils cause pro-inflammatory reactions, mast cells induce migration/maturation of skin DCs, the natural killer cells have natural cytotoxic capacity, the γδ T cells favor contact with hapten during the sensitization phase, and the innate lymphoid cells act in the early stages by secreting cytokines, as well as act in inflammation and tissue homeostasis. The antigen-specific inflammation is mediated by T cells, and each subtype of T cells (Th1/Tc1, Th2/Tc2, and Th17/Tc17) activates resident skin cells, thus contributing to inflammation. Skin's regulatory T cells have a strong ability to inhibit the proliferation of hapten-specific T cells, acting at the end of the Allergic Contact Dermatitis response and in the control of systemic immune responses. In this review, we report how cutaneous innate immunity is the first line of defense and focus its role in the activation of the adaptive immune response, with effector response induction and its regulation. PMID:29723367

Transforming growth factor beta induced FoxP3+ regulatory T cells suppress Th1 mediated experimental colitis.

PubMed

Fantini, M C; Becker, C; Tubbe, I; Nikolaev, A; Lehr, H A; Galle, P; Neurath, M F

2006-05-01

The imbalance between effector and regulatory T cells plays a central role in the pathogenesis of inflammatory bowel diseases. In addition to the thymus, CD4+CD25+ regulatory T cells can be induced in the periphery from a population of CD25- T cells by treatment with transforming growth factor beta (TGF-beta). Here, we analysed the in vivo function of TGF-beta induced regulatory T (Ti-Treg) cells in experimental colitis. Ti-Treg cells were generated in cell culture in the presence or absence of TGF-beta and tested for their regulatory potential in experimental colitis using the CD4+CD62L+ T cell transfer model. Ti-Treg cells significantly suppressed Th1 mediated colitis on CD4+CD62L+ T cell transfer in vivo, as shown by high resolution endoscopy, histology, immunohistochemistry, and cytokine analysis. Further analysis of in vivo and in vitro expanded Ti-Treg cells showed that exogenous interleukin 2 (IL-2) was crucial for survival and expansion of these cells. Our data suggest that regulatory Ti-Treg cells expand by TGF-beta and exogenous IL-2 derived from effector T cells at the site of inflammation. In addition to Tr1 and thymic CD4+CD25+ T cells, peripheral Ti-Treg cells emerge as a class of regulatory T cells with therapeutic potential in T cell mediated chronic intestinal inflammation.

Combination therapy with dendritic cells and lenalidomide is an effective approach to enhance antitumor immunity in a mouse colon cancer model.

PubMed

Vo, Manh-Cuong; Nguyen-Pham, Thanh-Nhan; Lee, Hyun-Ju; Jaya Lakshmi, Thangaraj; Yang, Seoyun; Jung, Sung-Hoon; Kim, Hyeoung-Joon; Lee, Je-Jung

2017-04-18

In this study, we investigated efficacy of lenalidomide in combination with tumor antigen-loaded dendritic cells (DCs) in murine colon cancer model. MC-38 cell lines were injected subcutaneously to establish colon cancer-bearing mice. After tumor growth, lenalidomide (50 mg/kg/day) was injected intraperitoneally on 3 consecutive days in combination with tumor antigen-loaded DC vaccination on days 8, 12, 16, and 20. The tumor antigen-loaded DCs plus lenalidomide combination treatment exhibited a significant inhibition of tumor growth compared with the other groups. These effects were associated with a reduction in immune suppressor cells, such as myeloid-derived suppressor cells and regulatory T cells, with the induction of immune effector cells, such as natural killer cells, CD4+ T cells and CD8+ T cells in spleen, and with the activation of cytotoxic T lymphocytes and NK cells. This study suggests that a combination of tumor antigen-loaded DC vaccination and lenalidomide synergistically enhanced antitumor immune response in the murine colon cancer model, by inhibiting the generation of immune suppressive cells and recovery of effector cells, and demonstrated superior polarization of Th1/Th2 balance in favor of Th1 immune response. This combination approach with DCs and lenalidomide may provide a new therapeutic option to improve the treatment of colon cancer.

Predictive Computational Modeling of the Mucosal Immune Responses during Helicobacter pylori Infection

PubMed Central

Carbo, Adria; Bassaganya-Riera, Josep; Pedragosa, Mireia; Viladomiu, Monica; Marathe, Madhav; Eubank, Stephen; Wendelsdorf, Katherine; Bisset, Keith; Hoops, Stefan; Deng, Xinwei; Alam, Maksudul; Kronsteiner, Barbara; Mei, Yongguo; Hontecillas, Raquel

2013-01-01

T helper (Th) cells play a major role in the immune response and pathology at the gastric mucosa during Helicobacter pylori infection. There is a limited mechanistic understanding regarding the contributions of CD4+ T cell subsets to gastritis development during H. pylori colonization. We used two computational approaches: ordinary differential equation (ODE)-based and agent-based modeling (ABM) to study the mechanisms underlying cellular immune responses to H. pylori and how CD4+ T cell subsets influenced initiation, progression and outcome of disease. To calibrate the model, in vivo experimentation was performed by infecting C57BL/6 mice intragastrically with H. pylori and assaying immune cell subsets in the stomach and gastric lymph nodes (GLN) on days 0, 7, 14, 30 and 60 post-infection. Our computational model reproduced the dynamics of effector and regulatory pathways in the gastric lamina propria (LP) in silico. Simulation results show the induction of a Th17 response and a dominant Th1 response, together with a regulatory response characterized by high levels of mucosal Treg) cells. We also investigated the potential role of peroxisome proliferator-activated receptor γ (PPARγ) activation on the modulation of host responses to H. pylori by using loss-of-function approaches. Specifically, in silico results showed a predominance of Th1 and Th17 cells in the stomach of the cell-specific PPARγ knockout system when compared to the wild-type simulation. Spatio-temporal, object-oriented ABM approaches suggested similar dynamics in induction of host responses showing analogous T cell distributions to ODE modeling and facilitated tracking lesion formation. In addition, sensitivity analysis predicted a crucial contribution of Th1 and Th17 effector responses as mediators of histopathological changes in the gastric mucosa during chronic stages of infection, which were experimentally validated in mice. These integrated immunoinformatics approaches characterized the induction of mucosal effector and regulatory pathways controlled by PPARγ during H. pylori infection affecting disease outcomes. PMID:24039925

Dendritic cell vaccination with a toll-like receptor agonist derived from mycobacteria enhances anti-tumor immunity.

PubMed

Vo, Manh-Cuong; Lee, Hyun-Ju; Kim, Jong-Seok; Hoang, My-Dung; Choi, Nu-Ri; Rhee, Joon Haeng; Lakshmanan, Vinoth-Kumar; Shin, Sung-Jae; Lee, Je-Jung

2015-10-20

Dendritic cell (DC)-based vaccines are considered useful in cancer immunotherapy, and the interaction of DC and adjuvants is important in the design of the next generation vaccines. In this study, whether DC combined with Rv2299c derived from mycobacteria could improve anti-tumor immune responses in a colon cancer mouse model was evaluated. MC38 cell lines were injected subcutaneously to establish colon-cancer-bearing mice and the following four groups were evaluated: PBS control, tumor antigen (TA) loaded-DC, Rv2299c, and a combination of TA-loaded-DC and Rv2299c. The combination treatment with TA-loaded-DC and Rv2299c exhibited greater inhibition of tumor growth compared to other groups. These effects were associated with the reduction of suppressor cells, such as myeloid-derived suppressor cells and regulatory T cells, and the induction of effector cells, such as CD4+ T cells and CD8+ T cells, in spleen, and with the activation of cytotoxic T Lymphocytes and NK cells. These results suggest that TA-loaded-DC vaccination with Rv2299c derived from mycobacteria enhanced anti-tumor immunity in a mouse colon cancer model by inhibiting the generation of immune-suppressive cells and recovering numbers of effector cells, and demonstrated superior polarization of the Th1/Th2 balance in favor of the Th1 immune response.

T helper 17.1 cells associate with multiple sclerosis disease activity: perspectives for early intervention.

PubMed

van Langelaar, Jamie; van der Vuurst de Vries, Roos M; Janssen, Malou; Wierenga-Wolf, Annet F; Spilt, Isis M; Siepman, Theodora A; Dankers, Wendy; Verjans, Georges M G M; de Vries, Helga E; Lubberts, Erik; Hintzen, Rogier Q; van Luijn, Marvin M

2018-05-01

Interleukin-17-expressing CD4+ T helper 17 (Th17) cells are considered as critical regulators of multiple sclerosis disease activity. However, depending on the species and pro-inflammatory milieu, Th17 cells are functionally heterogeneous, consisting of subpopulations that differentially produce interleukin-17, interferon-gamma and granulocyte macrophage colony-stimulating factor. In the current study, we studied distinct effector phenotypes of human Th17 cells and their correlation with disease activity in multiple sclerosis patients. T helper memory populations single- and double-positive for C-C chemokine receptor 6 (CCR6) and CXC chemokine receptor 3 (CXCR3) were functionally assessed in blood and/or cerebrospinal fluid from a total of 59 patients with clinically isolated syndrome, 35 untreated patients and 24 natalizumab-treated patients with relapsing-remitting multiple sclerosis, and nine patients with end-stage multiple sclerosis. Within the clinically isolated syndrome group, 23 patients had a second attack within 1 year and 26 patients did not experience subsequent attacks during a follow-up of >5 years. Low frequencies of T helper 1 (Th1)-like Th17 (CCR6+CXCR3+), and not Th17 (CCR6+CXCR3-) effector memory populations in blood strongly associated with a rapid diagnosis of clinically definite multiple sclerosis. In cerebrospinal fluid of clinically isolated syndrome and relapsing-remitting multiple sclerosis patients, Th1-like Th17 effector memory cells were abundant and showed increased production of interferon-gamma and granulocyte macrophage colony-stimulating factor compared to paired CCR6+ and CCR6-CD8+ T cell populations and their blood equivalents after short-term culturing. Their local enrichment was confirmed ex vivo using cerebrospinal fluid and brain single-cell suspensions. Across all pro-inflammatory T helper cells analysed in relapsing-remitting multiple sclerosis blood, Th1-like Th17 subpopulation T helper 17.1 (Th17.1; CCR6+CXCR3+CCR4-) expressed the highest very late antigen-4 levels and selectively accumulated in natalizumab-treated patients who remained free of clinical relapses. This was not found in patients who experienced relapses during natalizumab treatment. The enhanced potential of Th17.1 cells to infiltrate the central nervous system was supported by their predominance in cerebrospinal fluid of early multiple sclerosis patients and their preferential transmigration across human brain endothelial layers. These findings reveal a dominant contribution of Th1-like Th17 subpopulations, in particular Th17.1 cells, to clinical disease activity and provide a strong rationale for more specific and earlier use of T cell-targeted therapy in multiple sclerosis.

Desirable cytolytic immune effector cell recruitment by interleukin-15 dendritic cells.

PubMed

Van Acker, Heleen H; Beretta, Ottavio; Anguille, Sébastien; De Caluwé, Lien; Papagna, Angela; Van den Bergh, Johan M; Willemen, Yannick; Goossens, Herman; Berneman, Zwi N; Van Tendeloo, Viggo F; Smits, Evelien L; Foti, Maria; Lion, Eva

2017-02-21

Success of dendritic cell (DC) therapy in treating malignancies is depending on the DC capacity to attract immune effector cells, considering their reciprocal crosstalk is partially regulated by cell-contact-dependent mechanisms. Although critical for therapeutic efficacy, immune cell recruitment is a largely overlooked aspect regarding optimization of DC vaccination. In this paper we have made a head-to-head comparison of interleukin (IL)-15-cultured DCs and conventional IL-4-cultured DCs with regard to their proficiency in the recruitment of (innate) immune effector cells. Here, we demonstrate that IL-4 DCs are suboptimal in attracting effector lymphocytes, while IL15 DCs provide a favorable chemokine milieu for recruiting CD8+ T cells, natural killer (NK) cells and gamma delta (γδ) T cells. Gene expression analysis revealed that IL-15 DCs exhibit a high expression of chemokines involved in antitumor immune effector cell attraction, while IL-4 DCs display a more immunoregulatory profile characterized by the expression of Th2 and regulatory T cell-attracting chemokines. This is confirmed by functional data indicating an enhanced recruitment of granzyme B+ effector lymphocytes by IL-15 DCs, as compared to IL-4 DCs, and subsequent superior killing of tumor cells by the migrated lymphocytes. Elevated CCL4 gene expression in IL-15 DCs and lowered CCR5 expression on both migrated γδ T cells and NK cells, led to validation of increased CCL4 secretion by IL15 DCs. Moreover, neutralization of CCR5 prior to migration resulted in an important inhibition of γδ T cell and NK cell recruitment by IL-15 DCs. These findings further underscore the strong immunotherapeutic potential of IL-15 DCs.

Glycyrrhiza uralensis flavonoids present in anti-asthma formula, ASHMI™, inhibit memory Th2 responses in vitro and in vivo

PubMed Central

Yang, Nan; Patil, Sangita; Zhuge, Jian; Wen, Ming-Chun; Bolleddula, Jayaprakasam; Doddaga, Srinivasulu; Goldfarb, Joseph; Sampson, Hugh A.; Li, Xiu-Min

2012-01-01

Allergic asthma is associated with Th2-mediated inflammation. Several flavonoids were isolated from Glycyrrhiza uralensis, one of the herbs in the anti-asthma herbal medicine intervention, ASHMI. The aim of this investigation was to determine whether Glycyrrhiza uralensis flavonoids have inhibitory effects on memory Th2 responses in vitro, and antigen induced Th2 inflammation in vivo. The effects of three Glycyrrhiza uralensis flavonoids on effector memory Th2 cells, D10.G4.1 (D10 cells), were determined by measuring Th2 cytokine production. Isoliquiritigenin, 7, 4’-dihydroxyflavone (7, 4’-DHF) and liquiritigenin significantly suppressed IL-4 and IL-5 production in a dose dependent manner, 7, 4’-DHF being most potent. It was also evaluated for effects on D10 cell proliferation, GATA-3 expression and IL-4 mRNA expression, which were suppressed, with no loss of cell viability. Chronic treatment with 7, 4’-DHF in a murine model of allergic asthma not only significantly reduced eosinophilic pulmonary inflammation, serum IgE levels, IL-4 and IL-13 levels, but also increased IFN-γ production in lung cell cultures in response to antigen stimulation. PMID:23165939

Defining characteristics of classical Hodgkin lymphoma microenvironment T-helper cells

PubMed Central

Clear, Andrew; Owen, Andrew; Iqbal, Sameena; Lee, Abigail; Matthews, Janet; Wilson, Andrew; Calaminici, Maria; Gribben, John G.

2013-01-01

CD4+ T-helper cells (THs) dominate the classical Hodgkin lymphoma (CHL) microenvironment, but their role is poorly understood. Advances in flow cytometry and immunohistochemistry permit more detailed investigation of this aspect of CHL pathophysiology. To address the hypothesis that the TH-infiltrate, rather than being TH2-enriched, senescent and hypofunctional, is TH1 and activation marker-rich, cytokine-secretory and proliferative, we applied comprehensive flow cytometric immunophenotyping and functional assays of cytokine secretion/proliferation to TH cells from 18 CHL-derived single-cell suspensions (SCSs) compared to reactive lymph nodes (RLNs). CHL-derived TH cells express TH1-associated CXCR3/CCR5 and TNFα/IFNγ/interleukin-2 (IL-2) and less TH2-associated CCR3/CCR4, with no IL-4/IL-13. They lack exhaustion-/suppression-associated PD1, CD57 and terminally differentiated effector memory cells, with more central memory cells, activation-associated partners of Hodgkin Reed Sternberg (HRS) cell-expressed CD30/OX40-L/ICOS-L, and other activation markers. TH cell lines established from CHL and RLN-derived SCSs remain cytokine-secretory. We confirmed and extended these studies using tissue microarray immunohistochemistry (TMA-IHC) from a large CHL tissue bank (n = 122) and demonstrate TH1-associated TBET is abundant in CHL, and TH2-associated CMAF/GATA3 and exhaustion-associated PD1 expressed at significantly lower levels. These molecular insights into the CHL-associated TH offer potential diagnostic, prognostic and pharmacologically modifiable therapeutic targets and do not support the established view of a TH2-enriched, senescent/exhausted, hypofunctional, hypoproliferative infiltrate. PMID:24004665

Defining characteristics of classical Hodgkin lymphoma microenvironment T-helper cells.

PubMed

Greaves, Paul; Clear, Andrew; Owen, Andrew; Iqbal, Sameena; Lee, Abigail; Matthews, Janet; Wilson, Andrew; Calaminici, Maria; Gribben, John G

2013-10-17

CD4(+) T-helper cells (THs) dominate the classical Hodgkin lymphoma (CHL) microenvironment, but their role is poorly understood. Advances in flow cytometry and immunohistochemistry permit more detailed investigation of this aspect of CHL pathophysiology. To address the hypothesis that the TH-infiltrate, rather than being TH2-enriched, senescent and hypofunctional, is TH1 and activation marker-rich, cytokine-secretory and proliferative, we applied comprehensive flow cytometric immunophenotyping and functional assays of cytokine secretion/proliferation to TH cells from 18 CHL-derived single-cell suspensions (SCSs) compared to reactive lymph nodes (RLNs). CHL-derived TH cells express TH1-associated CXCR3/CCR5 and TNFα/IFNγ/interleukin-2 (IL-2) and less TH2-associated CCR3/CCR4, with no IL-4/IL-13. They lack exhaustion-/suppression-associated PD1, CD57 and terminally differentiated effector memory cells, with more central memory cells, activation-associated partners of Hodgkin Reed Sternberg (HRS) cell-expressed CD30/OX40-L/ICOS-L, and other activation markers. TH cell lines established from CHL and RLN-derived SCSs remain cytokine-secretory. We confirmed and extended these studies using tissue microarray immunohistochemistry (TMA-IHC) from a large CHL tissue bank (n = 122) and demonstrate TH1-associated TBET is abundant in CHL, and TH2-associated CMAF/GATA3 and exhaustion-associated PD1 expressed at significantly lower levels. These molecular insights into the CHL-associated TH offer potential diagnostic, prognostic and pharmacologically modifiable therapeutic targets and do not support the established view of a TH2-enriched, senescent/exhausted, hypofunctional, hypoproliferative infiltrate.

AllergoOncology - the impact of allergy in oncology: EAACI position paper.

PubMed

Jensen-Jarolim, E; Bax, H J; Bianchini, R; Capron, M; Corrigan, C; Castells, M; Dombrowicz, D; Daniels-Wells, T R; Fazekas, J; Fiebiger, E; Gatault, S; Gould, H J; Janda, J; Josephs, D H; Karagiannis, P; Levi-Schaffer, F; Meshcheryakova, A; Mechtcheriakova, D; Mekori, Y; Mungenast, F; Nigro, E A; Penichet, M L; Redegeld, F; Saul, L; Singer, J; Spicer, J F; Siccardi, A G; Spillner, E; Turner, M C; Untersmayr, E; Vangelista, L; Karagiannis, S N

2017-06-01

Th2 immunity and allergic immune surveillance play critical roles in host responses to pathogens, parasites and allergens. Numerous studies have reported significant links between Th2 responses and cancer, including insights into the functions of IgE antibodies and associated effector cells in both antitumour immune surveillance and therapy. The interdisciplinary field of AllergoOncology was given Task Force status by the European Academy of Allergy and Clinical Immunology in 2014. Affiliated expert groups focus on the interface between allergic responses and cancer, applied to immune surveillance, immunomodulation and the functions of IgE-mediated immune responses against cancer, to derive novel insights into more effective treatments. Coincident with rapid expansion in clinical application of cancer immunotherapies, here we review the current state-of-the-art and future translational opportunities, as well as challenges in this relatively new field. Recent developments include improved understanding of Th2 antibodies, intratumoral innate allergy effector cells and mediators, IgE-mediated tumour antigen cross-presentation by dendritic cells, as well as immunotherapeutic strategies such as vaccines and recombinant antibodies, and finally, the management of allergy in daily clinical oncology. Shedding light on the crosstalk between allergic response and cancer is paving the way for new avenues of treatment. © 2016 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.

AllergoOncology - The impact of Allergy in Oncology. EAACI Position Paper

PubMed Central

Jensen-Jarolim, E; Bax, HJ; Bianchini, R; Capron, M; Corrigan, C; Castells, M; Dombrowicz, D; Daniels-Wells, TR; Fazekas, J; Fiebiger, E; Gatault, S; Gould, HJ; Janda, J; Josephs, DH; Karagiannis, P; Levi-Schaffer, F; Meshcheryakova, A; Mechtcheriakova, D; Mekori, Y; Mungenast, F; Nigro, EA; Penichet, ML; Redegeld, F; Saul, L; Singer, J; Spicer, JF; Siccardi, AG; Spillner, E; Turner, MC; Untersmayr, E; Vangelista, L; Karagiannis, SN

2017-01-01

Th2 immunity and allergic immune surveillance play critical roles in host responses to pathogens, parasites and allergens. Numerous studies have reported significant links between Th2 responses and cancer, including insights into the functions of IgE antibodies and associated effector cells in both anti-tumour immune surveillance and therapy. The interdisciplinary field of AllergoOncology was given Task Force status by the European Academy of Allergy and Clinical Immunology in 2014. Affiliated expert groups focus on the interface between allergic responses and cancer, applied to immune surveillance, immunomodulation and the functions of IgE-mediated immune responses against cancer, to derive novel insights into more effective treatments. Co-incident with rapid expansion in clinical application of cancer immunotherapies, here we review the current state-of-the-art and future translational opportunities, as well as challenges in this relatively new field. Recent developments include improved understanding of Th2 antibodies, intra-tumoural innate allergy effector cells and mediators, IgE-mediated tumour antigen cross-presentation by dendritic cells, as well as immunotherapeutic strategies such as vaccines and recombinant antibodies, and finally, the management of allergy in daily clinical oncology. Shedding light on the cross-talk between allergic response and cancer is paving the way for new avenues of treatment. PMID:28032353

Cytokine networking of innate immunity cells: a potential target of therapy.

PubMed

Striz, Ilja; Brabcova, Eva; Kolesar, Libor; Sekerkova, Alena

2014-05-01

Innate immune cells, particularly macrophages and epithelial cells, play a key role in multiple layers of immune responses. Alarmins and pro-inflammatory cytokines from the IL (interleukin)-1 and TNF (tumour necrosis factor) families initiate the cascade of events by inducing chemokine release from bystander cells and by the up-regulation of adhesion molecules required for transendothelial trafficking of immune cells. Furthermore, innate cytokines produced by dendritic cells, macrophages, epithelial cells and innate lymphoid cells seem to play a critical role in polarization of helper T-cell cytokine profiles into specific subsets of Th1/Th2/Th17 effector cells or regulatory T-cells. Lastly, the innate immune system down-regulates effector mechanisms and restores homoeostasis in injured tissue via cytokines from the IL-10 and TGF (transforming growth factor) families mainly released from macrophages, preferentially the M2 subset, which have a capacity to induce regulatory T-cells, inhibit the production of pro-inflammatory cytokines and induce healing of the tissue by regulating extracellular matrix protein deposition and angiogenesis. Cytokines produced by innate immune cells represent an attractive target for therapeutic intervention, and multiple molecules are currently being tested clinically in patients with inflammatory bowel disease, rheumatoid arthritis, systemic diseases, autoinflammatory syndromes, fibrosing processes or malignancies. In addition to the already widely used blockers of TNFα and the tested inhibitors of IL-1 and IL-6, multiple therapeutic molecules are currently in clinical trials targeting TNF-related molecules [APRIL (a proliferation-inducing ligand) and BAFF (B-cell-activating factor belonging to the TNF family)], chemokine receptors, IL-17, TGFβ and other cytokines.

Application of tissue-specific NK and NKT cell activity for tumor immunotherapy

PubMed Central

Subleski, Jeff J.; Wiltrout, Robert H.; Weiss, Jonathan M.

2009-01-01

Natural killer (NK) and NKT cells are a first line of defense against pathogens and transformed cells. However, dysregulation of their function can lead to autoimmune disease. A better understanding of the mechanisms controlling NK and NKT effector function should lead to the development of improved strategies for the treatment of many diseases. The site in which NK and NKT cells reside should be taken into account, because accumulating evidence suggests that the tissue microenvironment strongly influences their function. In this regard, the liver represents a unique immunologic organ in which the balance between the need for tolerance and the ability to respond rapidly to pathogens and tissue injury is tightly regulated. NK cells in the liver have augmented cytolytic activity as compared to other organs, which is consistent with a role for liver-associated NK cells in being critical effector cells for inhibiting tumor metastasis in the liver. Several studies also suggest that hepatic NKT cells have different functions than those in other organs. Whereas splenic and thymic NKT cells have been shown to suppress diabetes development, facilitate the induction of systemic tolerance and are regulated by IL-4 and other Th2 cytokines, certain subsets of NKT cells in the liver are important sources of Th1 cytokines such as Interferon gamma, and are the primary mediators of anti-tumor responses. The unique properties and roles as critical effector cells make NK and NKT cells within the liver microenvironment attractive targets of immunotherapeutic approaches that have the goal of controlling tumor metastasis in the liver. PMID:19682859

Systemic T Cells Immunosuppression of Glioma Stem Cell-Derived Exosomes Is Mediated by Monocytic Myeloid-Derived Suppressor Cells

PubMed Central

Domenis, Rossana; Cesselli, Daniela; Toffoletto, Barbara; Bourkoula, Evgenia; Caponnetto, Federica; Manini, Ivana; Beltrami, Antonio Paolo; Ius, Tamara; Skrap, Miran; Di Loreto, Carla

2017-01-01

A major contributing factor to glioma development and progression is its ability to evade the immune system. Nano-meter sized vesicles, exosomes, secreted by glioma-stem cells (GSC) can act as mediators of intercellular communication to promote tumor immune escape. Here, we investigated the immunomodulatory properties of GCS-derived exosomes on different peripheral immune cell populations. Healthy donor peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3, anti-CD28 and IL-2, were treated with GSC-derived exosomes. Phenotypic characterization, cell proliferation, Th1/Th2 cytokine secretion and intracellular cytokine production were analysed by distinguishing among effector T cells, regulatory T cells and monocytes. In unfractionated PBMCs, GSC-derived exosomes inhibited T cell activation (CD25 and CD69 expression), proliferation and Th1 cytokine production, and did not affect cell viability or regulatory T-cell suppression ability. Furthermore, exosomes were able to enhance proliferation of purified CD4+ T cells. In PBMCs culture, glioma-derived exosomes directly promoted IL-10 and arginase-1 production and downregulation of HLA-DR by unstimulated CD14+ monocytic cells, that displayed an immunophenotype resembling that of monocytic myeloid-derived suppressor cells (Mo-MDSCs). Importantly, the removal of CD14+ monocytic cell fraction from PBMCs restored T-cell proliferation. The same results were observed with exosomes purified from plasma of glioblastoma patients. Our results indicate that glioma-derived exosomes suppress T-cell immune response by acting on monocyte maturation rather than on direct interaction with T cells. Selective targeting of Mo-MDSC to treat glioma should be considered with regard to how immune cells allow the acquirement of effector functions and therefore counteracting tumor progression. PMID:28107450

Systemic T Cells Immunosuppression of Glioma Stem Cell-Derived Exosomes Is Mediated by Monocytic Myeloid-Derived Suppressor Cells.

PubMed

Domenis, Rossana; Cesselli, Daniela; Toffoletto, Barbara; Bourkoula, Evgenia; Caponnetto, Federica; Manini, Ivana; Beltrami, Antonio Paolo; Ius, Tamara; Skrap, Miran; Di Loreto, Carla; Gri, Giorgia

2017-01-01

A major contributing factor to glioma development and progression is its ability to evade the immune system. Nano-meter sized vesicles, exosomes, secreted by glioma-stem cells (GSC) can act as mediators of intercellular communication to promote tumor immune escape. Here, we investigated the immunomodulatory properties of GCS-derived exosomes on different peripheral immune cell populations. Healthy donor peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3, anti-CD28 and IL-2, were treated with GSC-derived exosomes. Phenotypic characterization, cell proliferation, Th1/Th2 cytokine secretion and intracellular cytokine production were analysed by distinguishing among effector T cells, regulatory T cells and monocytes. In unfractionated PBMCs, GSC-derived exosomes inhibited T cell activation (CD25 and CD69 expression), proliferation and Th1 cytokine production, and did not affect cell viability or regulatory T-cell suppression ability. Furthermore, exosomes were able to enhance proliferation of purified CD4+ T cells. In PBMCs culture, glioma-derived exosomes directly promoted IL-10 and arginase-1 production and downregulation of HLA-DR by unstimulated CD14+ monocytic cells, that displayed an immunophenotype resembling that of monocytic myeloid-derived suppressor cells (Mo-MDSCs). Importantly, the removal of CD14+ monocytic cell fraction from PBMCs restored T-cell proliferation. The same results were observed with exosomes purified from plasma of glioblastoma patients. Our results indicate that glioma-derived exosomes suppress T-cell immune response by acting on monocyte maturation rather than on direct interaction with T cells. Selective targeting of Mo-MDSC to treat glioma should be considered with regard to how immune cells allow the acquirement of effector functions and therefore counteracting tumor progression.

Th17 Cells Coordinate with Th22 Cells in Maintaining Homeostasis of Intestinal Tissues and both are Depleted in SIV-Infected Macaques.

PubMed

Xu, Huanbin; Wang, Xiaolei; Veazey, Ronald S

2014-05-01

Th17 and Th22 cells are thought to function as innate regulators of mucosal antimicrobial responses, tissue inflammation and mucosal integrity, yet their role in persistent SIV infection is still unclear. Here we compared Th17 and Th22 cells in their phenotype, effector/cytokine function, and frequency in blood and intestinal mucosal tissues, and correlate levels with mucosal damage in SIV-infected rhesus macaques. We found that Th17/Th22 cells share similar features in that both highly produce TNF-α and IL-2 and express CCR5 in intestinal tissues; yet very few show cytotoxic functions, as evidenced by lack of IFN-γ and granzyme B production. Further, Th17/Th22 cells display distinct tissue-specific distributions. Both Th17 and Th22 cells and cytokine secretion were significantly depleted in both blood and intestine in chronically SIV-infected macaques. The frequency of Th17 and Th22 cells in the intestine positively correlated with percentages of intestinal CD4+ T cells and negatively with damage to intestinal mucosa, and plasma viral loads in SIV infection. These findings indicate Th17 and Th22 cells share considerable functions, and may coordinate in innate mucosal immune responses, and their regional loss in the intestine may be associated with local mucosal immune dysfunction in persistent HIV/SIV infection.

Th17 Cells Coordinate with Th22 Cells in Maintaining Homeostasis of Intestinal Tissues and both are Depleted in SIV-Infected Macaques

PubMed Central

Xu, Huanbin; Wang, Xiaolei; Veazey, Ronald S.

2014-01-01

Th17 and Th22 cells are thought to function as innate regulators of mucosal antimicrobial responses, tissue inflammation and mucosal integrity, yet their role in persistent SIV infection is still unclear. Here we compared Th17 and Th22 cells in their phenotype, effector/cytokine function, and frequency in blood and intestinal mucosal tissues, and correlate levels with mucosal damage in SIV-infected rhesus macaques. We found that Th17/Th22 cells share similar features in that both highly produce TNF-α and IL-2 and express CCR5 in intestinal tissues; yet very few show cytotoxic functions, as evidenced by lack of IFN-γ and granzyme B production. Further, Th17/Th22 cells display distinct tissue-specific distributions. Both Th17 and Th22 cells and cytokine secretion were significantly depleted in both blood and intestine in chronically SIV-infected macaques. The frequency of Th17 and Th22 cells in the intestine positively correlated with percentages of intestinal CD4+ T cells and negatively with damage to intestinal mucosa, and plasma viral loads in SIV infection. These findings indicate Th17 and Th22 cells share considerable functions, and may coordinate in innate mucosal immune responses, and their regional loss in the intestine may be associated with local mucosal immune dysfunction in persistent HIV/SIV infection. PMID:25364618

Down-regulation of Notch signaling pathway reverses the Th1/Th2 imbalance in tuberculosis patients.

PubMed

Li, Qifeng; Zhang, Hui; Yu, Liang; Wu, Chao; Luo, Xinhui; Sun, He; Ding, Jianbing

2018-01-01

Th1/Th2 imbalance to Th2 is of significance in the peripheral immune responses in Tuberculosis (TB) development. However, the mechanisms for Th1/Th2 imbalance are still not well determined. Notch signaling pathway is involved in the peripheral T cell activation and effector cell differentiation. However, whether it affects Th1/Th2 imbalance in TB patients is still not known. Here, we used γ-secretase inhibitor (DAPT) to treat the peripheral blood mononuclear cells (PBMCs) from healthy people or individuals with latent or active TB infection in vitro, respectively. Then, the Th1/Th2 ratios were determined by flow cytometry, and cytokines of IFN-γ, IL-4, IL-10 in the culture supernatant were measured by CBA method. The Notch signal pathway associated proteins Hes1, GATA3 and T-bet were quantitated by real-time PCR or immunoblotting. Our results showed that DAPT effectively inhibited the protein level of Hes1. In TB patients, the Th2 ratio increased in the PBMCs, alone with the high expression of GATA3 and IL-4, resulting in the high ratios of Th2/Th1 and GATA3/T-bet in TB patients. However, Th2 cells ratio decreased after blocking the Notch signaling pathway by DAPT and the Th2/Th1 ratio in TB patients were DAPT dose-dependent, accompanied by the decrease of IL-4 and GATA3. But, its influence on Th1 ratio and Th1 related T-bet and IFN-γ levels were not significant. In conclusion, our results suggest that blocking Notch signaling by DAPT could inhibit Th2 responses and restore Th1/Th2 imbalance in TB patients. Copyright © 2017. Published by Elsevier B.V.

Role of Th17 Cell in Tubercle Bacillus Infection

NASA Astrophysics Data System (ADS)

Zhang, Dandan

2018-01-01

Tuberculosis is mainly a kind of lung disease. Normal immune cell expression can inhibit proliferation of tubercle bacillus in the lungs, but this may also lead to chronic inflammation and pathological lesion. Th17 cell is a newly discovered CD4 + effector T cell subsets, whose differentiation and roles are influenced by various cytokines in the surrounding environment. Th17 cell plays an important role in resisting tubercle bacillus infection, but also it may cause pathological damage through the inflammatory response. Therefore, to balance two kinds of roles of Th17 cells in tubercle bacillus infection can effectively protect the body. This paper intends to do a summary on differentiation, regulation, and biological functions of Th17 cell.

Chimeric PD-1:28 Receptor Upgrades Low-Avidity T cells and Restores Effector Function of Tumor-Infiltrating Lymphocytes for Adoptive Cell Therapy.

PubMed

Schlenker, Ramona; Olguín-Contreras, Luis Felipe; Leisegang, Matthias; Schnappinger, Julia; Disovic, Anja; Rühland, Svenja; Nelson, Peter J; Leonhardt, Heinrich; Harz, Hartmann; Wilde, Susanne; Schendel, Dolores J; Uckert, Wolfgang; Willimsky, Gerald; Noessner, Elfriede

2017-07-01

Inherent intermediate- to low-affinity T-cell receptors (TCR) that develop during the natural course of immune responses may not allow sufficient activation for tumor elimination, making the majority of T cells suboptimal for adoptive T-cell therapy (ATT). TCR affinity enhancement has been implemented to provide stronger T-cell activity but carries the risk of creating undesired cross-reactivity leading to potential serious adverse effects in clinical application. We demonstrate here that engineering of low-avidity T cells recognizing a naturally processed and presented tumor-associated antigen with a chimeric PD-1:28 receptor increases effector function to levels seen with high-avidity T cells of identical specificity. Upgrading the function of low-avidity T cells without changing the TCR affinity will allow a large arsenal of low-avidity T cells previously thought to be therapeutically inefficient to be considered for ATT. PD-1:28 engineering reinstated Th1 function in tumor-infiltrating lymphocytes that had been functionally disabled in the human renal cell carcinoma environment without unleashing undesired Th2 cytokines or IL10. Involved mechanisms may be correlated to restoration of ERK and AKT signaling pathways. In mouse tumor models of ATT, PD-1:28 engineering enabled low-avidity T cells to proliferate stronger and prevented PD-L1 upregulation and Th2 polarization in the tumor milieu. Engineered T cells combined with checkpoint blockade secreted significantly more IFNγ compared with T cells without PD-1:28, suggesting a beneficial combination with checkpoint blockade therapy or other therapeutic strategies. Altogether, the supportive effects of PD-1:28 engineering on T-cell function make it an attractive tool for ATT. Cancer Res; 77(13); 3577-90. ©2017 AACR . ©2017 American Association for Cancer Research.

Decreased circulating T regulatory lymphocytes in obese patients undergoing bariatric surgery.

PubMed

Agabiti-Rosei, Claudia; Trapletti, Valentina; Piantoni, Silvia; Airò, Paolo; Tincani, Angela; De Ciuceis, Carolina; Rossini, Claudia; Mittempergher, Francesco; Titi, Amin; Portolani, Nazario; Caletti, Stefano; Coschignano, Maria Antonietta; Porteri, Enzo; Tiberio, Guido A M; Pileri, Paola; Solaini, Leonardo; Kumar, Rajesh; Ministrini, Silvia; Agabiti Rosei, Enrico; Rizzoni, Damiano

2018-01-01

It has been previously demonstrated that T lymphocytes may be involved in the development of hypertension and microvascular remodeling, and that circulating T effector lymphocytes may be increased in hypertension. In particular, Th1 and Th 17 lymphocytes may contribute to the progression of hypertension and microvascular damage while T-regulatory (Treg) lymphocytes seem to be protective in this regard. However, no data is available about patients with severe obesity, in which pronounced microvascular alterations were observed. We have investigated 32 severely obese patients undergoing bariatric surgery, as well as 24 normotensive lean subjects and 12 hypertensive lean subjects undergoing an elective surgical intervention. A peripheral blood sample was obtained before surgery for assessment of CD4+ T lymphocyte subpopulations. Lymphocyte phenotype was evaluated by flow cytometry in order to assess T-effector and Treg lymphocytes. A marked reduction of several Treg subpopulations was observed in obese patients compared with controls, together with an increased in CD4+ effector memory T-effector cells. In severely obese patients, Treg lymphocytes are clearly reduced and CD4+ effector memory cells are increased. It may be hypothesized that they might contribute to the development of marked microvascular alterations previously observed in these patients.

Alkaline Cytosolic pH and High Sodium Hydrogen Exchanger 1 (NHE1) Activity in Th9 Cells.

PubMed

Singh, Yogesh; Zhou, Yuetao; Shi, Xiaolong; Zhang, Shaqiu; Umbach, Anja T; Salker, Madhuri S; Lang, Karl S; Lang, Florian

2016-11-04

CD4 + T helper 9 (Th9) cells are a newly discovered Th cell subset that produce the pleiotropic cytokine IL-9. Th9 cells can protect against tumors and provide resistance against helminth infections. Given their pivotal role in the adaptive immune system, understanding Th9 cell development and the regulation of IL-9 production could open novel immunotherapeutic opportunities. The Na + /H + exchanger 1 (NHE1; gene name Slc9α1)) is critically important for regulating intracellular pH (pH i ), cell volume, migration, and cell survival. The pH i influences cytokine secretion, activities of membrane-associated enzymes, ion transport, and other effector signaling molecules such as ATP and Ca 2+ levels. However, whether NHE1 regulates Th9 cell development or IL-9 secretion has not yet been defined. The present study explored the role of NHE1 in Th9 cell development and function. Th cell subsets were characterized by flow cytometry and pH i was measured using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein-acetoxymethyl ester (BCECF-AM) dye. NHE1 functional activity was estimated from the rate of realkalinization following an ammonium pulse. Surprisingly, in Th9 cells pH i and NHE1 activity were significantly higher than in all other Th cell subsets (Th1/Th2/Th17 and induced regulatory T cells (iTregs)). NHE1 transcript levels and protein abundance were significantly higher in Th9 cells than in other Th cell subsets. Inhibition of NHE1 by siRNA-NHE1 or with cariporide in Th9 cells down-regulated IL-9 and ATP production. NHE1 activity, Th9 cell development, and IL-9 production were further blunted by pharmacological inhibition of protein kinase Akt1/Akt2. Our findings reveal that Akt1/Akt2 control of NHE1 could be an important physiological regulator of Th9 cell differentiation, IL-9 secretion, and ATP production. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

T cell source of type 1 cytokines determines illness patterns in respiratory syncytial virus-infected mice.

PubMed Central

Tang, Y. W.; Graham, B. S.

1997-01-01

Manipulation of the cytokine microenvironment at the time of vaccination can influence immune responses to remote challenge, providing a strategy to study the molecular pathogenesis of respiratory syncytial virus (RSV) vaccine-enhanced disease in the mouse model. Although treatment with antibody against IL-4 or recombinant IL-12 (rIL-12) at the time of formalin-inactivated RSV vaccination induced a similar shift in the pattern of cytokine mRNA expression upon live virus challenge, anti-IL-4 treated mice had increased CD8+ cytotoxic T lymphocyte activity and reduced illness compared with rIL-12-treated mice. To define effector mechanisms responsible for these patterns, CD4+ and/or CD8+ T lymphocytes were selectively depleted in vivo at the time of RSV challenge. In rIL-12-treated mice, CD4+ lymphocytes made the largest contribution to IFN-gamma mRNA, RSV clearance, and illness, while in anti-IL-4 treated mice, CD8+ lymphocytes were the major effector. The effector responsible for virus clearance also mediated illness, suggesting that efficiency of virus clearance determined disease expression. These results demonstrate that the phenotype of effector cells involved in the immune response to virus challenge may be a more important determinant of disease than patterns of cytokine expression classically assigned to Th1 and Th2 lymphocytes. PMID:9151790

Induction of tolerance towards TNP entails down-regulation of an autoimmune attack.

PubMed Central

Zöller, M; Andrighetto, G

1988-01-01

In order to follow the process of induction and maintainance of tolerance, BALB/c mice were tolerized by free hapten, and effector and regulatory cell interactions were analysed by limiting-dilution (LD) cultures. Injection of trinitrobenzenesulphonic acid (TNBS) resulted, predominantly, in the activation and expansion of self-reactive cytotoxic T cells (CTL), which were observed transiently at frequencies comparable to allo-specific CTL. In addition, self-reactive helper T cells (Th) were activated and expanded in tolerized mice. TNP-specific reactivity was difficult to evaluate, since cytotoxic activity against haptenized self followed the pattern of self-reactivity throughout the test period. But in LD cultures determining proliferation, two populations of Th responding to TNP-self were observed, while only one Th population could be detected in response to self. Expansion/activation of Th and CTL precursors (CTLp) was followed by activation of suppressor T cells (Ts). The suppressor population could be divided into two subpopulations, one interfering with Th, the second interacting directly with CTL (veto cells). The results indicate that during the induction of tolerance, animals pass through an autoimmune attack, with expansion and activation of self-reactive clones (CTL, Th). The final status of non-responsiveness towards TNP is not due to the deletion of effector or regulatory cells, but results from the establishment of a steady state of dominance of self-reactive and TNP-self-reactive suppression. PMID:2965095

Leptin Directly Promotes T Cell Glycolytic Metabolism to Drive Effector T cell Differentiation in Autoimmunity

PubMed Central

Gerriets, Valerie A.; Danzaki, Keiko; Kishton, Rigel J.; Eisner, William; Nichols, Amanda G.; Saucillo, Donte C.; Shinohara, Mari L.; MacIver, Nancie J.

2016-01-01

Upon activation, T cells require energy for growth, proliferation and function. Effector T cells (Teff), such as Th1 and Th17, utilize high levels of glucose uptake and glycolysis to fuel proliferation and function. In contrast, Treg instead require oxidative metabolism to fuel suppressive function. It remains unknown how Teff/Treg metabolism is altered in settings of malnutrition, when nutrients are limited and circulating leptin levels are low. We therefore examined the role of malnutrition and associated hypoleptinemia on Teff versus Treg. We found that both malnutrition-associated hypoleptinemia and T cell-specific leptin receptor knockout suppressed Teff number, function, and glucose metabolism, but did not alter Treg metabolism or suppressive function. Using the autoimmune model EAE, we confirmed that fasting-induced hypoleptinemia altered Teff, but not Treg, glucose metabolism and function in vivo, leading to decreased disease severity. To explore potential mechanisms, we examined HIF-1α, a key regulator of Th17 differentiation and Teff glucose metabolism, and found HIF-1α expression was decreased in T cell-specific leptin receptor knockout Th17 cells, and in Teff cells from fasted EAE mice, but was unchanged in Treg. Altogether, these data demonstrate a selective, cell-intrinsic requirement for leptin to upregulate glucose metabolism and maintain function in Teff, but not Treg. PMID:27222115

CD11c-expressing cells affect Treg behavior in the meninges during CNS infection1

PubMed Central

O’Brien, Carleigh A.; Overall, Christopher; Konradt, Christoph; O’Hara Hall, Aisling C.; Hayes, Nikolas W.; Wagage, Sagie; John, Beena; Christian, David A.; Hunter, Christopher A.; Harris, Tajie H.

2017-01-01

Treg cells play an important role in the CNS during multiple infections as well as autoimmune inflammation, but the behavior of this cell type in the CNS has not been explored. In mice, infection with Toxoplasma gondii leads to a Th1-polarized parasite-specific effector T cell response in the brain. Similarly, the Treg cells in the CNS during T. gondii infection are Th1-polarized, exemplified by T-bet, CXCR3, and IFN-γ expression. Unlike effector CD4+ T cells, an MHC Class II tetramer reagent specific for T. gondii did not recognize Treg cells isolated from the CNS. Likewise, TCR sequencing revealed minimal overlap in TCR sequence between effector and regulatory T cells in the CNS. Whereas effector T cells are found in the brain parenchyma where parasites are present, Treg cells were restricted to the meninges and perivascular spaces. The use of intravital imaging revealed that activated CD4+ T cells within the meninges were highly migratory, while Treg cells moved more slowly and were found in close association with CD11c+ cells. To test whether the behavior of Tregs in the meninges is influenced by interactions with CD11c+ cells, mice were treated with anti-LFA-1 antibodies to reduce the number of CD11c+ cells in this space. The anti-LFA-1 treatment led to fewer contacts between Tregs and the remaining CD11c+ cells and increased the speed of Treg cell migration. These data suggest that Treg cells are anatomically restricted within the CNS and the interaction with CD11c+ populations regulates their local behavior during T. gondii infection. PMID:28389591

CD4+ T Cells Recognizing PE/PPE Antigens Directly or via Cross Reactivity Are Protective against Pulmonary Mycobacterium tuberculosis Infection

PubMed Central

Sayes, Fadel; Pawlik, Alexandre; Frigui, Wafa; Gröschel, Matthias I.; Crommelynck, Samuel; Fayolle, Catherine; Cia, Felipe; Bancroft, Gregory J.; Bottai, Daria; Leclerc, Claude; Brosch, Roland; Majlessi, Laleh

2016-01-01

Mycobacterium tuberculosis (Mtb), possesses at least three type VII secretion systems, ESX-1, -3 and -5 that are actively involved in pathogenesis and host-pathogen interaction. We recently showed that an attenuated Mtb vaccine candidate (Mtb Δppe25-pe19), which lacks the characteristic ESX-5-associated pe/ppe genes, but harbors all other components of the ESX-5 system, induces CD4+ T-cell immune responses against non-esx-5-associated PE/PPE protein homologs. These T cells strongly cross-recognize the missing esx-5-associated PE/PPE proteins. Here, we characterized the fine composition of the functional cross-reactive Th1 effector subsets specific to the shared PE/PPE epitopes in mice immunized with the Mtb Δppe25-pe19 vaccine candidate. We provide evidence that the Mtb Δppe25-pe19 strain, despite its significant attenuation, is comparable to the WT Mtb strain with regard to: (i) its antigenic repertoire related to the different ESX systems, (ii) the induced Th1 effector subset composition, (iii) the differentiation status of the Th1 cells induced, and (iv) its particular features at stimulating the innate immune response. Indeed, we found significant contribution of PE/PPE-specific Th1 effector cells in the protective immunity against pulmonary Mtb infection. These results offer detailed insights into the immune mechanisms underlying the remarkable protective efficacy of the live attenuated Mtb Δppe25-pe19 vaccine candidate, as well as the specific potential of PE/PPE proteins as protective immunogens. PMID:27467705

The aryl hydrocarbon receptor and food allergy.

PubMed

Schulz, V J; Smit, J J; Pieters, R H H

2013-06-01

The immune system is important for protection against pathogens and malignant cells. However, malfunction of the immune system can also result in detrimental auto-immune diseases, inflammatory diseases, cancers and allergies. The aryl hydrocarbon receptor (AhR), present in numerous tissues and cell subsets, including cells of the immune system, plays an important role in the functioning of the immune system. Activation of the AhR is for example associated with various effects on dendritic cells (DCs), regulatory T cells and the Th1/Th2 cell balance. These cells play a major role in the development of food allergy. Food allergy is an increasing health problem in both humans and animals. Despite the knowledge in risk factors and cellular mechanisms for food allergy, no approved treatments are available yet. Recently, it has been shown that activation of the AhR by dioxin-like compounds suppresses allergic sensitization by suppressing the absolute number of precursor and effector T cells, by preserving CD4(+)CD25(+)Foxp3(+) Treg cells and by affecting DCs and their interaction with effector T cells. Future research should elucidate whether and how AhR activation can be used to interfere in food allergic responses in humans and in animals. This may lead to new prevention strategies and therapeutic possibilities for food allergy.

Polarization of T-helper lymphocytes toward the Th2 phenotype in uremic patients.

PubMed

Libetta, C; Rampino, T; Dal Canton, A

2001-08-01

T-helper (Th) lymphocytes consist of Th1 and Th2 subsets. Th1 cells are effectors of cell-mediated immunity and secrete interferon-gamma (IFN-gamma), which recruits new Th1 cells in cooperation with interleukin-12 (IL-12; produced by monocytes) and inhibits Th2 differentiation. Th2 cells produce IL-4 and IL-10, which inhibit IFN-gamma secretion and cell immunity. We investigated whether the impaired immune response in uremia is associated with an altered balance of Th1/Th2. Peripheral-blood mononuclear cells (PBMCs) were collected from patients with chronic renal failure (CRF) on conservative treatment (CRF patients), patients with end-stage renal disease (ESRD) on regular hemodialysis therapy (ESRD-HD patients), and healthy controls (CON). CD4(+) cells were isolated from PBMCs by negative selection using a magnetic labeling system. PBMCs and purified CD4(+) cells were cultured in Iscove's medium and Iscove's medium plus mitogens (phytohemagglutinin and lipopolysaccharide). IFN-gamma, IL-12, IL-4, and IL-10 were measured in supernatant. The constitutive release of IL-4 and IL-10 by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was increased by five to eight times in comparison with CON (P < 0.001). Constitutive IFN-gamma release by PBMCs of ESRD-HD patients was undetectable, although they secreted an increased amount of IL-12. Mitogen-stimulated release of IFN-gamma by PBMCs and CD4(+) cells of CRF and ESRD-HD patients was blunted (average PBMCs: CON, 115.8 pg/2 x10(6) cells; CRF, 81.8 pg/2 x10(6) cells; ESRD-HD, 9.3 pg/2 x10(6) cells; CD4(+) cells: CON, 358.0 pg/5 x 10(5) cells; CRF, 165.4 pg/5 x 10(5) cells; ESRD-HD, 43.5 pg/5 x 10(5) cells). The ability of PBMCs of ESRD-HD patients to secrete IFN-gamma was recovered after IL-4 and IL-10 neutralization. Uremia is associated with a prevalence of Th1 over Th2 cells and a configuration of cytokine network that depresses cell-mediated immunity.

IL-4/IL-13 Heteroreceptor Influences Th17 Cell Conversion and Sensitivity to Regulatory T Cell Suppression To Restrain Experimental Allergic Encephalomyelitis.

PubMed

Barik, Subhasis; Ellis, Jason S; Cascio, Jason A; Miller, Mindy M; Ukah, Tobechukwu K; Cattin-Roy, Alexis N; Zaghouani, Habib

2017-10-01

IL-4 and IL-13 have been defined as anti-inflammatory cytokines that can counter myelin-reactive T cells and modulate experimental allergic encephalomyelitis. However, it is not known whether endogenous IL-4 and IL-13 contribute to the maintenance of peripheral tolerance and whether their function is coordinated with T regulatory cells (Tregs). In this study, we used mice in which the common cytokine receptor for IL-4 and IL-13, namely the IL-4Rα/IL-13Rα1 (13R) heteroreceptor (HR), is compromised and determined whether the lack of signaling by endogenous IL-4 and IL-13 through the HR influences the function of effector Th1 and Th17 cells in a Treg-dependent fashion. The findings indicate that mice-deficient for the HR (13R -/- ) are more susceptible to experimental allergic encephalomyelitis than mice sufficient for the HR (13R +/+ ) and develop early onset and more severe disease. Moreover, Th17 cells from 13R -/- mice had reduced ability to convert to Th1 cells and displayed reduced sensitivity to suppression by Tregs relative to Th17 effectors from 13R +/+ mice. These observations suggest that IL-4 and IL-13 likely operate through the HR and influence Th17 cells to convert to Th1 cells and to acquire increased sensitivity to suppression, leading to control of immune-mediated CNS inflammation. These previously unrecognized findings shed light on the intricacies underlying the contribution of cytokines to peripheral tolerance and control of autoimmunity. Copyright © 2017 by The American Association of Immunologists, Inc.

Retinoic Acid Is Essential for Th1 Cell Lineage Stability and Prevents Transition to a Th17 Cell Program

PubMed Central

Brown, Chrysothemis C.; Esterhazy, Daria; Sarde, Aurelien; London, Mariya; Pullabhatla, Venu; Osma-Garcia, Ines; al-Bader, Raya; Ortiz, Carla; Elgueta, Raul; Arno, Matthew; de Rinaldis, Emanuele; Mucida, Daniel; Lord, Graham M.; Noelle, Randolph J.

2015-01-01

Summary CD4+ T cells differentiate into phenotypically distinct T helper cells upon antigenic stimulation. Regulation of plasticity between these CD4+ T-cell lineages is critical for immune homeostasis and prevention of autoimmune disease. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARα, sustains stable expression of Th1 lineage specifying genes, as well as repressing genes that instruct Th17-cell fate. RA signaling is essential for limiting Th1-cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our study identifies RA-RARα as a key component of the regulatory network governing maintenance and plasticity of Th1-cell fate and defines an additional pathway for the development of Th17 cells. PMID:25769610

[Anaphylactic reactions to low-molecular weight chemicals].

PubMed

Nowak, Daria; Panaszek, Bernard

2015-02-06

Low-molecular weight chemicals (haptens) include a large group of chemical compounds occurring in work environment, items of everyday use (cleaning products, clothing, footwear, gloves, furniture), jewelry (earrings, bracelets), drugs, especially in cosmetics. They cause type IV hypersensitive reactions. During the induction phase of delayed-type hypersensitivity, haptens form complexes with skin proteins. After internalization through antigen presenting cells, they are bound to MHC class II molecules. Next, they are exposed against specific T-lymphocytes, what triggers activation of Th1 cells mainly. After repeating exposition to that hapten, during effector phase, Th1 induce production of cytokines affecting non-specific inflammatory cells. Usually, it causes contact dermatitis. However, occasionally incidence of immediate generalized reactions after contact with some kinds of haptens is noticed. A question arises, how the hapten does induce symptoms which are typical for anaphylaxis, and what contributes to amplification of this mechanism. It seems that this phenomenon arises from pathomechanism occurring in contact urticaria syndrome in which an anaphylactic reaction may be caused either by contact of sensitized skin with protein antigens, high-molecular weight allergens, or haptens. One of the hypotheses indicates the leading role of basophiles in this process. Their contact with haptens, may cause to release mediators of immediate allergic reaction (histamine, eicosanoids) and to produce cytokines corresponding to Th2 cells profile. Furthermore, Th17 lymphocytes secreting pro-inflammatory interleukin-17 might be engaged into amplifying hypersensitivity into immediate reactions and regulatory T-cells may play role in the process, due to insufficient control of the activity of effector cells.

Differential requirements of CD4(+) T-cell signals for effector cytotoxic T-lymphocyte (CTL) priming and functional memory CTL development at higher CD8(+) T-cell precursor frequency.

PubMed

Umeshappa, Channakeshava S; Nanjundappa, Roopa H; Xie, Yufeng; Freywald, Andrew; Xu, Qingyong; Xiang, Jim

2013-04-01

Increased CD8(+) T-cell precursor frequency (PF) precludes the requirement of CD4(+) helper T (Th) cells for primary CD8(+) cytotoxic T-lymphocyte (CTL) responses. However, the key questions of whether unhelped CTLs generated at higher PF are functional effectors, and whether unhelped CTLs can differentiate into functional memory cells at higher PF are unclear. In this study, ovalbumin (OVA) -pulsed dendritic cells (DC(OVA)) derived from C57BL/6, CD40 knockout (CD40(-/-)) or CD40 ligand knockout (CD40L(-/-)) mice were used to immunize C57BL/6, Ia(b-/-), CD40(-/-) or CD40L(-/-) mice, whose PF was previously increased with transfer of 1 × 10(6) CD8(+) T cells derived from OVA-specific T-cell receptor (TCR) transgenic OTI, OTI(CD40(-/-)) or OTI(CD40L(-/-)) mice. All the immunized mice were then assessed for effector and memory CTL responses. Following DC immunization, relatively comparable CTL priming occurred without CD4(+) T-cell help and Th-provided CD40/CD40L signalling. In addition, the unhelped CTLs were functional effectors capable of inducing therapeutic immunity against established OVA-expressing tumours. In contrast, the functional memory development of CTLs was severely impaired in the absence of CD4(+) T-cell help and CD40/CD40L signalling. Finally, unhelped memory CTLs failed to protect mice against lethal tumour challenge. Taken together, these results demonstrate that CD4(+) T-cell help at higher PF, is not required for effector CTL priming, but is required for functional memory CTL development against cancer. Our data may impact the development of novel preventive and therapeutic approaches in cancer patients with compromised CD4(+) T-cell functions. © 2012 Blackwell Publishing Ltd.

A Novel Sphingomyelinase-Like Enzyme in Ixodes scapularis Tick Saliva Drives Host CD4+ T cells to Express IL-4

PubMed Central

Alarcon-Chaidez, F. J.; Boppana, V. D.; Hagymasi, A.T.; Adler, A. J.; Wikel, S. K.

2009-01-01

Tick feeding modulates host immune responses. Tick-induced skewing of host CD4+ T cells towards a Th2 cytokine profile facilitates transmission of tick-borne pathogens that would otherwise be neutralized by Th1 cytokines. Tick-derived factors that drive this Th2 response have not previously been characterized. In the current study, we examined an I. scapularis cDNA library prepared at 18-24 hours of feeding and identified and expressed a tick gene with homology to Loxosceles spider venom proteins with sphingomyelinase activity. This I. scapularis sphingomyelinase-like (IsSMase) protein is a Mg+2-dependent, neutral (pH 7.4) form of sphingomyelinase. Significantly, in an in vivo TCR transgenic adoptive transfer assay IsSMase programmed host CD4+ T cells to express the hallmark Th2 effector cytokine IL-4. IsSMase appears to directly program host CD4 T cell IL-4 expression (as opposed to its metabolic by-products) because induced IL-4 expression was not altered when enzymatic activity was neutralized. TCR transgenic CD4 T cell proliferation (CFSE-dilution) was also significantly increased by IsSMase. Furthermore, a Th2 response is superimposed onto a virally-primed Th1 response by IsSMase. Thus, IsSMase is the first identified tick molecule capable of programming host CD4+ T cells to express IL-4. PMID:19292772

Spatiotemporal Monitoring of Pseudomonas syringae Effectors via Type III Secretion Using Split Fluorescent Protein Fragments[OPEN

PubMed Central

2017-01-01

Pathogenic gram-negative bacteria cause serious diseases in animals and plants. These bacterial pathogens use the type III secretion system (T3SS) to deliver effector proteins into host cells; these effectors then localize to different subcellular compartments to attenuate immune responses by altering biological processes of the host cells. The fluorescent protein (FP)-based approach to monitor effectors secreted from bacteria into the host cells is not possible because the folded FP prevents effector delivery through the T3SS. Therefore, we optimized an improved variant of self-assembling split super-folder green fluorescent protein (sfGFPOPT) system to investigate the spatiotemporal dynamics of effectors delivered through bacterial T3SS into plant cells. In this system, effectors are fused to 11th β-strand of super-folder GFP (sfGFP11), and when delivered into plant cells expressing sfGFP1-10 β-strand (sfGFP1-10OPT), the two proteins reconstitute GFP fluorescence. We generated a number of Arabidopsis thaliana transgenic lines expressing sfGFP1-10OPT targeted to various subcellular compartments to facilitate localization of sfGFP11-tagged effectors delivered from bacteria. We demonstrate the efficacy of this system using Pseudomonas syringae effectors AvrB and AvrRps4 in Nicotiana benthamiana and transgenic Arabidopsis plants. The versatile split sfGFPOPT system described here will facilitate a better understanding of bacterial invasion strategies used to evade plant immune responses. PMID:28619883

Recent thymic emigrants are biased against the T-helper type 1 and toward the T-helper type 2 effector lineage.

PubMed

Hendricks, Deborah W; Fink, Pamela J

2011-01-27

After intrathymic development, T cells exit the thymus and join the peripheral T-cell pool. Such recent thymic emigrants (RTEs) undergo both phenotypic and functional maturation during the first 3 weeks they reside in the periphery. Using a well-controlled in vitro polarization scheme, we now show that CD4(+) RTEs are defective in T-helper (Th) type 0 (Th0), Th1, Th17, and regulatory T-cell lineage commitment, with dampened cytokine production and transcription factor expression. In contrast, CD4(+) RTES are biased toward the Th2 lineage both in vitro and in vivo, with more robust interleukin-4, interleukin-5, and interleukin-13 production than their mature naive counterparts. Coculture experiments demonstrate that mature naive T cells influence neighboring RTEs in their Th responses. In adoptive hosts, CD4(+) RTEs drive production of the Th2-associated antibody isotype immunoglobulin G1 and mediate airway inflammatory disease. This bias in RTEs likely results from dampened negative regulation of the Th2 lineage by diminished levels of T-bet, a key Th1 transcription factor. CD4(+) RTEs thus represent a transitional population with a distinct interpretation of, and response to, immunologic cues. These characteristics may be beneficial during the postthymic maturation period by leading to the avoidance of inappropriate immune responses, particularly in lymphopenic neonates and adults.

Leptin directly promotes T-cell glycolytic metabolism to drive effector T-cell differentiation in a mouse model of autoimmunity.

PubMed

Gerriets, Valerie A; Danzaki, Keiko; Kishton, Rigel J; Eisner, William; Nichols, Amanda G; Saucillo, Donte C; Shinohara, Mari L; MacIver, Nancie J

2016-08-01

Upon activation, T cells require energy for growth, proliferation, and function. Effector T (Teff) cells, such as Th1 and Th17 cells, utilize high levels of glycolytic metabolism to fuel proliferation and function. In contrast, Treg cells require oxidative metabolism to fuel suppressive function. It remains unknown how Teff/Treg-cell metabolism is altered when nutrients are limited and leptin levels are low. We therefore examined the role of malnutrition and associated hypoleptinemia on Teff versus Treg cells. We found that both malnutrition-associated hypoleptinemia and T cell-specific leptin receptor knockout suppressed Teff-cell number, function, and glucose metabolism, but did not alter Treg-cell metabolism or suppressive function. Using the autoimmune mouse model EAE, we confirmed that fasting-induced hypoleptinemia altered Teff-cell, but not Treg-cell, glucose metabolism, and function in vivo, leading to decreased disease severity. To explore potential mechanisms, we examined HIF-1α, a key regulator of Th17 differentiation and Teff-cell glucose metabolism, and found HIF-1α expression was decreased in T cell-specific leptin receptor knockout Th17 cells, and in Teff cells from fasted EAE mice, but was unchanged in Treg cells. Altogether, these data demonstrate a selective, cell-intrinsic requirement for leptin to upregulate glucose metabolism and maintain function in Teff, but not Treg cells. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CD11c-Expressing Cells Affect Regulatory T Cell Behavior in the Meninges during Central Nervous System Infection.

PubMed

O'Brien, Carleigh A; Overall, Christopher; Konradt, Christoph; O'Hara Hall, Aisling C; Hayes, Nikolas W; Wagage, Sagie; John, Beena; Christian, David A; Hunter, Christopher A; Harris, Tajie H

2017-05-15

Regulatory T cells (Tregs) play an important role in the CNS during multiple infections, as well as autoimmune inflammation, but the behavior of this cell type in the CNS has not been explored. In mice, infection with Toxoplasma gondii leads to a Th1-polarized parasite-specific effector T cell response in the brain. Similarly, Tregs in the CNS during T. gondii infection are Th1 polarized, as exemplified by their T-bet, CXCR3, and IFN-γ expression. Unlike effector CD4 + T cells, an MHC class II tetramer reagent specific for T. gondii did not recognize Tregs isolated from the CNS. Likewise, TCR sequencing revealed minimal overlap in TCR sequence between effector T cells and Tregs in the CNS. Whereas effector T cells are found in the brain parenchyma where parasites are present, Tregs were restricted to the meninges and perivascular spaces. The use of intravital imaging revealed that activated CD4 + T cells within the meninges were highly migratory, whereas Tregs moved more slowly and were found in close association with CD11c + cells. To test whether the behavior of Tregs in the meninges is influenced by interactions with CD11c + cells, mice were treated with anti-LFA-1 Abs to reduce the number of CD11c + cells in this space. The anti-LFA-1 treatment led to fewer contacts between Tregs and the remaining CD11c + cells and increased the speed of Treg migration. These data suggest that Tregs are anatomically restricted within the CNS, and their interaction with CD11c + populations regulates their local behavior during T. gondii infection. Copyright © 2017 by The American Association of Immunologists, Inc.

Lupus Nephritis: An Overview of Recent Findings

PubMed Central

de Zubiria Salgado, Alberto; Herrera-Diaz, Catalina

2012-01-01

Lupus nephritis (LN) is one of the most serious complications of systemic lupus erythematosus (SLE) since it is the major predictor of poor prognosis. In susceptible individuals suffering of SLE, in situ formation and deposit of immune complexes (ICs) from apoptotic bodies occur in the kidneys as a result of an amplified epitope immunological response. IC glomerular deposits generate release of proinflammatory cytokines and cell adhesion molecules causing inflammation. This leads to monocytes and polymorphonuclear cells chemotaxis. Subsequent release of proteases generates endothelial injury and mesangial proliferation. Presence of ICs promotes adaptive immune response and causes dendritic cells to release type I interferon. This induces maturation and activation of infiltrating T cells, and amplification of Th2, Th1 and Th17 lymphocytes. Each of them, amplify B cells and activates macrophages to release more proinflammatory molecules, generating effector cells that cannot be modulated promoting kidney epithelial proliferation and fibrosis. Herein immunopathological findings of LN are reviewed. PMID:22536486

Basophils and allergic inflammation

PubMed Central

Siracusa, Mark C.; Kim, Brian S.; Spergel, Jonathan M.; Artis, David

2013-01-01

Basophils were discovered by Paul Ehrlich in 1879 and represent the least abundant granulocyte population in mammals. The relative rarity of basophils and their phenotypic similarities with mast cells resulted in this cell lineage being historically overlooked, both clinically and experimentally. However, recent studies in humans and murine systems have shown that basophils perform non-redundant effector functions and significantly contribute to the development and progression of TH2 cytokine-mediated inflammation. Although the potential functions of murine and human basophils have provoked some controversy, recent genetic approaches indicate that basophils can migrate into lymphoid tissues and, in some circumstances, cooperate with other immune cells to promote optimal TH2 cytokine responses in vivo. This article provides a brief historical perspective on basophil-related research and discusses recent studies that have identified previously unappreciated molecules and pathways that regulate basophil development, activation and function in the context of allergic inflammation. Further, we highlight the unique effector functions of basophils and discuss their contributions to the development and pathogenesis of allergic inflammation in human disease. Finally, we discuss the therapeutic potential of targeting basophils in preventing or alleviating the development and progression of allergic inflammation. PMID:24075190

Th cells promote CTL survival and memory via acquired pMHC-I and endogenous IL-2 and CD40L signaling and by modulating apoptosis-controlling pathways.

PubMed

Umeshappa, Channakeshava Sokke; Xie, Yufeng; Xu, Shulin; Nanjundappa, Roopa Hebbandi; Freywald, Andrew; Deng, Yulin; Ma, Hong; Xiang, Jim

2013-01-01

Involvement of CD4(+) helper T (Th) cells is crucial for CD8(+) cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4(+) Th's signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4(+) Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4(+) T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2K(b)/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4(+) Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4(+) Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4(+) Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy.

Lenalidomide Synergistically Enhances the Effect of Dendritic Cell Vaccination in a Model of Murine Multiple Myeloma.

PubMed

Nguyen-Pham, Thanh-Nhan; Jung, Sung-Hoon; Vo, Manh-Cuong; Thanh-Tran, Huong-Thi; Lee, Youn-Kyung; Lee, Hyun-Ju; Choi, Nu-Ri; Hoang, My-Dung; Kim, Hyeoung-Joon; Lee, Je-Jung

2015-10-01

We investigated the efficacy of lenalidomide (LEN) in combination with dendritic cell (DC) vaccination in the MOPC-315 murine myeloma model. After tumor growth, LEN was injected intraperitoneally for 4 consecutive days in combination with DC vaccination. The combination of LEN and vaccination efficiently inhibited tumor growth compared with the single agents alone. A cytotoxic assay revealed that the anticancer effects of DC vaccination plus LEN involved not only generation of antigen-specific cytotoxic T lymphocytes but also NK cells. Vaccinated mice had reduced numbers of suppressor cells, including both myeloid-derived suppressor cells and regulatory T cells, in the spleen. The proportions of CD4+ and CD8+ T cells increased in the spleen, and a Th1 cytokine (interferon-γ) rather than a Th2 cytokine (interleukin-10) was synthesized in response to tumor antigens. LEN enhanced the innate immune response by modulating NK cell numbers and function. In addition, LEN reduced the production levels of angiogenesis-inducing factors in tumor-bearing mice. Together, these results suggest that a combination of LEN and DC vaccination may synergistically enhance anticancer immunity in the murine myeloma model, by inhibiting immunosuppressor cells and stimulating effector cells, as well as effectively polarizing the Th1/Th2 balance in favor of a Th1-specific immune response.

The Th17 Lineage: From Barrier Surfaces Homeostasis to Autoimmunity, Cancer, and HIV-1 Pathogenesis.

PubMed

Wacleche, Vanessa Sue; Landay, Alan; Routy, Jean-Pierre; Ancuta, Petronela

2017-10-19

The T helper 17 (Th17) cells represent a subset of CD4+ T-cells with unique effector functions, developmental plasticity, and stem-cell features. Th17 cells bridge innate and adaptive immunity against fungal and bacterial infections at skin and mucosal barrier surfaces. Although Th17 cells have been extensively studied in the context of autoimmunity, their role in various other pathologies is underexplored and remains an area of open investigation. This review summarizes the history of Th17 cell discovery and the current knowledge relative to the beneficial role of Th17 cells in maintaining mucosal immunity homeostasis. We further discuss the concept of Th17 pathogenicity in the context of autoimmunity, cancer, and HIV infection, and we review the most recent discoveries on molecular mechanisms regulating HIV replication/persistence in pathogenic Th17 cells. Finally, we stress the need for novel fundamental research discovery-based Th17-specific therapeutic interventions to treat pathogenic conditions associated with Th17 abnormalities, including HIV infection.

Innovative T Cell-Targeted Therapy for Ovarian Cancer

DTIC Science & Technology

2014-10-01

cell effector functions: a blend of innate programming and acquired plasticity. Nat Rev Immunol 2010; 10(7): 467-78. 22. Gomes AQ, Martins DS...costimulator (ICOS) is critical for the development of human T(H)17 cells . Sci Transl Med 2010; 2(55): 55ra78. 36. Cua DJ, Tato CM. Innate IL-17...intestinal epithelial lympho- cytes (17, 18). In contrast, circulating γδ T cells can be found in the blood and lymphoid organs, and are dominated by γδ

T cell subsets in cord blood are influenced by maternal allergy and associated with atopic dermatitis.

PubMed

Fu, Yujing; Lou, Hongfei; Wang, Chengshuo; Lou, Wei; Wang, Yang; Zheng, Tao; Zhang, Luo

2013-03-01

This study aimed to investigate the influence of maternal allergy on cord blood regulatory and effector T cells and to evaluate their role as a predictor of atopic dermatitis (AD) during the first 2 yr of life. Seventy mother-infant pairs were recruited in this prospective birth cohort study (21 allergic and 49 non-allergic mothers). Cord blood samples were collected and assayed for the percentage of regulatory T cells (Treg), interferon-γ (IFN-γ), and interleukin-4 (IL-4) producing T cells (Th1 and Th2, respectively) using flow cytometry. Experiments were undertaken to assess the function of cord blood CD4(+) CD25(+) CD127(-) Treg cells by cell proliferation and cytokine responses. Their offspring at the age of 2 yr old were evaluated by dermatologists to determine whether they had AD. During the first 2 yr of life, 15.7% of the children developed a physician-diagnosed AD. A significantly increased percentage of Th2 cell was observed in cord blood of newborns with maternal allergy. Treg/Th2 ratio significantly decreased among the offspring of allergic mothers. Treg cell-associated suppression of Th2 response was attenuated in Der p1-stimulated CD4(+) CD25(-) T cells from the offspring of allergic mothers. Children with reduced Th1/Th2 (p = 0.001, OR = 0.37) and Treg/Th2 (p = 0.001, OR = 0.47) ratio in cord blood had a higher risk of developing AD. Maternal allergic status is associated with increased percentage of IL-4(+) CD4(+) T cells and a reduced Treg/Th2 ratio in cord blood at their children's birth, which may predispose to an increased risk for developing AD. © 2013 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

Acquisition of Pneumococci Specific Effector and Regulatory Cd4+ T Cells Localising within Human Upper Respiratory-Tract Mucosal Lymphoid Tissue

PubMed Central

Pido-Lopez, Jeffrey; Kwok, William W.; Mitchell, Timothy J.; Heyderman, Robert S.; Williams, Neil A.

2011-01-01

The upper respiratory tract mucosa is the location for commensal Streptococcus (S.) pneumoniae colonization and therefore represents a major site of contact between host and bacteria. The CD4+ T cell response to pneumococcus is increasingly recognised as an important mediator of immunity that protects against invasive disease, with data suggesting a critical role for Th17 cells in mucosal clearance. By assessing CD4 T cell proliferative responses we demonstrate age-related sequestration of Th1 and Th17 CD4+ T cells reactive to pneumococcal protein antigens within mucosal lymphoid tissue. CD25hi T cell depletion and utilisation of pneumococcal specific MHCII tetramers revealed the presence of antigen specific Tregs that utilised CTLA-4 and PDL-1 surface molecules to suppress these responses. The balance between mucosal effector and regulatory CD4+ T cell immunity is likely to be critical to pneumococcal commensalism and the prevention of unwanted pathology associated with carriage. However, if dysregulated, such responses may render the host more susceptible to invasive pneumococcal infection and adversely affect the successful implementation of both polysaccharide-conjugate and novel protein-based pneumococcal vaccines. PMID:22144893

PU.1 regulates TCR expression by modulating GATA-3 activity

PubMed Central

Chang, Hua-Chen; Han, Ling; Jabeen, Rukhsana; Carotta, Sebastian; Nutt, Stephen L.; Kaplan, Mark H.

2009-01-01

The Ets transcription factor PU.1 is a master regulator for the development of multiple lineages during hematopoiesis. The expression pattern of PU.1 is dynamically regulated during early T lineage development in the thymus. We previously revealed that PU.1 delineates heterogeneity of effector Th2 populations. In this study, we further define the function of PU.1 on the Th2 phenotype using mice that specifically lack PU.1 in T cells using an lck-Cre transgene with a conditional Sfpi1 allele (Sfpi1lck-/-). While deletion of PU.1 by the lck-Cre transgene does not affect T cell development, Sfpi1lck-/- T cells have a lower activation threshold than wild type T cells. When TCR engagement is limiting, Sfpi1lck-/- T cells cultured in Th2 polarizing conditions secrete higher levels of Th2 cytokines and have greater cytokine homogeneity than wild type cells. We show that PU.1 modulates the levels of TCR expression in CD4+ T cells by regulating the DNA-binding activity of GATA-3 and limiting GATA-3 regulation of TCR gene expression. GATA-3 dependent regulation of TCR expression is also observed in Th1 and Th2 cells. In CD4+ T cells, PU.1 expression segregates into subpopulations of cells that have lower levels of surface TCR, suggesting that PU.1 contributes to the heterogeneity of TCR expression. Thus, we have identified a mechanism whereby increased GATA-3 function in the absence of the antagonizing activity of PU.1 leads to increased TCR expression, a reduced activation threshold and increased homogeneity in Th2 populations. PMID:19801513

T-bet promotes the accumulation of encephalitogenic Th17 cells in the CNS.

PubMed

Grifka-Walk, Heather M; Segal, Benjamin M

2017-03-15

T-bet enhances the encephalitogenicity of myelin-reactive CD4 + T cells, however its mechanism of action is unknown. In this study we show that T-bet confers a competitive advantage for the accumulation of IL-23 conditioned Th17 effector cells in the central nervous system (CNS). Impaired migration of T-bet deficient Th17 cells to the CNS is associated with altered expression of adhesion molecules and chemokine receptors on their cell surface. Our data suggest that therapeutic targeting of T-bet in individuals with Th17-mediated autoimmune demyelinating disease may inhibit inflammatory infiltration of the CNS and, hence, clinical exacerbations. Copyright © 2016 Elsevier B.V. All rights reserved.

Programmed cell death 1 inhibits inflammatory helper T-cell development through controlling the innate immune response

PubMed Central

Rui, Yuxiang; Honjo, Tasuku; Chikuma, Shunsuke

2013-01-01

Programmed cell death 1 (PD-1) is an inhibitory coreceptor on immune cells and is essential for self-tolerance because mice genetically lacking PD-1 (PD-1−/−) develop spontaneous autoimmune diseases. PD-1−/− mice are also susceptible to severe experimental autoimmune encephalomyelitis (EAE), characterized by a massive production of effector/memory T cells against myelin autoantigen, the mechanism of which is not fully understood. We found that an increased primary response of PD-1−/− mice to heat-killed mycobacteria (HKMTB), an adjuvant for EAE, contributed to the enhanced production of T-helper 17 (Th17) cells. Splenocytes from HKMTB-immunized, lymphocyte-deficient PD-1−/− recombination activating gene (RAG)2−/− mice were found to drive antigen-specific Th17 cell differentiation more efficiently than splenocytes from HKMTB-immunized PD-1+/+ RAG2−/− mice. This result suggested PD-1’s involvement in the regulation of innate immune responses. Mice reconstituted with PD-1−/− RAG2−/− bone marrow and PD-1+/+ CD4+ T cells developed more severe EAE compared with the ones reconstituted with PD-1+/+ RAG2−/− bone marrow and PD-1+/+ CD4+ T cells. We found that upon recognition of HKMTB, CD11b+ macrophages from PD-1−/− mice produced very high levels of IL-6, which helped promote naive CD4+ T-cell differentiation into IL-17–producing cells. We propose a model in which PD-1 negatively regulates antimycobacterial responses by suppressing innate immune cells, which in turn prevents autoreactive T-cell priming and differentiation to inflammatory effector T cells. PMID:24043779

Th Cells Promote CTL Survival and Memory via Acquired pMHC-I and Endogenous IL-2 and CD40L Signaling and by Modulating Apoptosis-Controlling Pathways

PubMed Central

Umeshappa, Channakeshava Sokke; Xie, Yufeng; Xu, Shulin; Nanjundappa, Roopa Hebbandi; Freywald, Andrew; Deng, Yulin; Ma, Hong; Xiang, Jim

2013-01-01

Involvement of CD4+ helper T (Th) cells is crucial for CD8+ cytotoxic T lymphocyte (CTL)-mediated immunity. However, CD4+ Th’s signals that govern CTL survival and functional memory are still not completely understood. In this study, we assessed the role of CD4+ Th cells with acquired antigen-presenting machineries in determining CTL fates. We utilized an adoptive co-transfer into CD4+ T cell-sufficient or -deficient mice of OTI CTLs and OTII Th cells or Th cells with various gene deficiencies pre-stimulated in vitro by ovalbumin (OVA)-pulsed dendritic cell (DCova). CTL survival was kinetically assessed in these mice using FITC-anti-CD8 and PE-H-2Kb/OVA257-264 tetramer staining by flow cytometry. We show that by acting via endogenous CD40L and IL-2, and acquired peptide-MHC-I (pMHC-I) complex signaling, CD4+ Th cells enhance survival of transferred effector CTLs and their differentiation into the functional memory CTLs capable of protecting against highly-metastasizing tumor challenge. Moreover, RT-PCR, flow cytometry and Western blot analysis demonstrate that increased survival of CD4+ Th cell-helped CTLs is matched with enhanced Akt1/NF-κB activation, down-regulation of TRAIL, and altered expression profiles with up-regulation of prosurvival (Bcl-2) and down-regulation of proapoptotic (Bcl-10, Casp-3, Casp-4, Casp-7) molecules. Taken together, our results reveal a previously unexplored mechanistic role for CD4+ Th cells in programming CTL survival and memory recall responses. This knowledge could also aid in the development of efficient adoptive CTL cancer therapy. PMID:23785406

PolyI:C and mouse survivin artificially embedding human 2B peptide induce a CD4+ T cell response to autologous survivin in HLA-A*2402 transgenic mice.

PubMed

Kasamatsu, Jun; Takahashi, Shojiro; Azuma, Masahiro; Matsumoto, Misako; Morii-Sakai, Akiko; Imamura, Masahiro; Teshima, Takanori; Takahashi, Akari; Hirohashi, Yoshihiko; Torigoe, Toshihiko; Sato, Noriyuki; Seya, Tsukasa

2015-01-01

CD4(+) T cell effectors are crucial for establishing antitumor immunity. Dendritic cell maturation by immune adjuvants appears to facilitate subset-specific CD4(+) T cell proliferation, but the adjuvant effect for CD4 T on induction of cytotoxic T lymphocytes (CTLs) is largely unknown. Self-antigenic determinants with low avidity are usually CD4 epitopes in mutated proteins with tumor-associated class I-antigens (TAAs). In this study, we made a chimeric version of survivin, a target of human CTLs. The chimeric survivin, where human survivin-2B containing a TAA was embedded in the mouse survivin frame (MmSVN2B), was used to immunize HLA-A-2402/K(b)-transgenic (HLA24(b)-Tg) mice. Subcutaneous administration of MmSVN2B or xenogeneic human survivin (control HsSNV2B) to HLA24(b)-Tg mice failed to induce an immune response without co-administration of an RNA adjuvant polyI:C, which was required for effector induction in vivo. Although HLA-A-2402/K(b) presented the survivin-2B peptide in C57BL/6 mice, 2B-specific tetramer assays showed that no CD8(+) T CTLs specific to survivin-2B proliferated above the detection limit in immunized mice, even with polyI:C treatment. However, the CD4(+) T cell response, as monitored by IFN-γ, was significantly increased in mice given polyI:C+MmSVN2B. The Th1 response and antibody production were enhanced in the mice with polyI:C. The CD4 epitope responsible for effector function was not Hs/MmSNV13-27, a nonconserved region between human and mouse survivin, but region 53-67, which was identical between human and mouse survivin. These results suggest that activated, self-reactive CD4(+) helper T cells proliferate in MmSVN2B+polyI:C immunization and contribute to Th1 polarization followed by antibody production, but hardly participate in CTL induction. Copyright © 2014 Elsevier GmbH. All rights reserved.

T Helper1/T Helper2 Cells and Resistance/Susceptibility to Leishmania Infection: Is This Paradigm Still Relevant?

PubMed Central

Alexander, James; Brombacher, Frank

2012-01-01

Work in large part on Leishmania major in the 1980s identified two distinct apparently counter-regulatory CD4+ T cell populations, T helper (h)1 and Th2, that controlled resistance/susceptibility to infection respectively. However, the generation of IL-4−/− mice in the 1990s questioned the paramount role of this Th2 archetypal cytokine in the non-healing response to Leishmania infection. The more recent characterization of CD4+ T cell regulatory populations and further effector CD4+ T helper populations, Th17, Th9, and T follicular (f)h cells as well as the acknowledged plasticity in T helper cell function has further added to the complexity of host pathogen interactions. These interactions are complicated by the multiplicity of cells that respond to CD4+ T cell subset signatory cytokines, as well as the diversity of Leishmania species that are often subject to significantly different immune-regulatory controls. In this article we review current knowledge with regard to the role of CD4+ T cells and their products during Leishmania infection. In particular we update on our studies using conditional IL-4Rα gene-deficient mice that have allowed dissection of the cell interplay dictating the disease outcomes of the major Leishmania species infecting humans. PMID:22566961

Regulatory T Cells Subvert Mycobacterial Containment in Patients Failing Extensively Drug-resistant TB Treatment.

PubMed

Davids, Malika; Pooran, Anil S; Pietersen, Elize; Wainwright, Helen C; Binder, Anke; Warren, Robin; Dheda, Keertan

2018-02-09

The advent of extensively (XDR-TB) and totally drug-resistant TB, with limited or no treatment options, has facilitated renewed interest in host directed immunotherapy, particularly for therapeutically destitute patients. However, the selection and utility of such approaches depend upon understanding the host immune response in XDR-TB, which hitherto remains unexplored. To determine the host immunological profile in patients with XDR-TB, compared to drug-sensitive TB, using peripheral blood and explanted lung tissue. Blood and explanted lung tissue were obtained from patients with XDR-TB (n=31), drug-sensitive TB (DS-TB, n=20) and presumed latent-TB infection (LTBI, n=20). T-cell phenotype (Th1/Th2/Th17/Tregs) was evaluated in all patient groups, and Treg function assessed in XDR-TB non-responders by co-culturing PPD pre-primed effector T-cells with H37Rv-infected monocyte-derived macrophages, with or without autologous Tregs. Mycobacterial containment was evaluated by counting colony-forming units. Patients failing XDR-TB treatment had an altered immuno-phenotype characterized by a substantial increase in the frequency (median; IQR) of CD4+CD25+FoxP3+ regulatory T-cells (11.5; 5.9-15.2) compared to DS-TB (3.4 %; 1.6-5.73; p < 0.001) and presumed LTBI (1.8 % 1.2-2.3; p < 0.001), which was unrelated to disease duration. Tregs isolated from XDR-TB patients suppressed T-cell proliferation (up to 90%) and subverted containment of H37Rv-infected monocyte-derived macrophages (by 30%; p= 0.03) by impairing effector T-cell function through a mechanism independent of direct cell-to-cell contact, IL-10, TGF-beta and CTLA-4. Collectively, these data suggest that Tregs may be contributing to immune dysfunction, and bacterial persistence, in patients with XDR-TB. The relevant cellular pathways may serve as potential targets for immunotherapeutic intervention.

Different competitive capacities of Stat4- and Stat6-deficient CD4+ T cells during lymphophenia-driven proliferation.

PubMed

Sanchez-Guajardo, Vanesa; Borghans, José A M; Marquez, Maria-Elena; Garcia, Sylvie; Freitas, Antonio A

2005-02-01

The outcome of an immune response relies on the competitive capacities acquired through differentiation of CD4(+) T cells into Th1 or Th2 effector cells. Because Stat4 and Stat6 proteins are implicated in the Th1 vs Th2 generation and maintenance, respectively, we compare in this study the kinetics of Stat4(-/-) and Stat6(-/-) CD4(+) T cells during competitive bone marrow reconstitution and lymphopenia-driven proliferation. After bone marrow transplantation, both populations reconstitute the peripheral T cell pools equally well. After transfer into lymphopenic hosts, wild-type and Stat6(-/-) CD4(+) T cells show a proliferation advantage, which is early associated with the expression of an active phospho-Stat4 and the down-regulation of Stat6. Despite these differences, Stat4- and Stat6-deficient T cells reach similar steady state numbers. However, when both Stat4(-/-) and Stat6(-/-) CD4(+) T cells are coinjected into the same hosts, the Stat6(-/-) cells become dominant and out-compete Stat4(-/-) cells. These findings suggest that cell activation, through the Stat4 pathway and the down-regulation of Stat6, confers to pro-Th1 T cells a slight proliferation advantage that in a competitive situation has major late repercussions, because it modifies the final homeostatic equilibrium of the populations and favors the establishment of Th1 CD4(+) T cell dominance.

Eight color immunophenotyping of T-, B- and NK-cell subpopulations for characterization of chronic immunodeficiencies.

PubMed

A, Boldt; S, Borte; S, Fricke; K, Kentouche; F, Emmrich; M, Borte; F, Kahlenberg; U, Sack

2014-01-16

Background: The heterogeneity of primary and secondary immunodeficiencies demands for the development of a comprehensive flow cytometric screening system, based on reference values that support a standardized immunophenotypic characterization of most lymphocyte subpopulations. Methods: Peripheral blood samples from healthy adult volunteers (n=25) were collected and split into eight panel fractions (100µl each). Subsequently, pre-mixed 8-color antibody cocktails were incubated per specific panel of whole blood to detect and differentiate cell subsets of: (i) a general lymphocyte overviews, (ii) B-cell subpopulations, (iii) CD4+ subpopulations, (iv) CD8+ subpopulations, (v) regulatory T-cells, (vi) recent thymic emigrants, (vii) NK-cell subpopulations, (viii) NK-cell activation markers. All samples were lysed, washed and measured by flow cytometry. FACS DIVA software was used for data analysis and calculation of quadrant statistics (mean values, standard error of mean, percentile ranges). Results: Whole blood staining of lymphocytes provided the analysis of: (i) CD3+, 4+, 8+, 19+, 16/56+, and activated CD4/8 cells; (ii) immature, naïve, non-switched/switched, memory, (activated) CD21 low , transitional B-cells, plasmablasts/plasmacells; (iii and iv) naïve, central memory, effector, effector memory, TH1/TH2/TH17-like and CCR5+CD8-cells; (v) CD25+, regulatory T-cells (naïve/memory, HLA-DR+); (vi) α/β- and γ/δ-T-cells, recent thymic emigrants in CD4/CD8 cells; (vii) immature/mature CD56 bright , CD94/NKG2D+ NK-cells; and (viii) Nkp30, 44, 46 and CD57+NK-cells. Clinical examples and quadrant statistics are provided. Conclusion: The present study represents a practical approach to standardize the immunophenotyping of most T-, B- and NK-cell subpopulations. That allows differentiating, whether abnormalities or developmental shifts observed in lymphocyte subpopulations originates either from primary or secondary immunological disturbance. © 2014 Clinical Cytometry Society. Copyright © 2014 Clinical Cytometry Society.

Estradiol Enhances CD4+ T-Cell Anti-Viral Immunity by Priming Vaginal DCs to Induce Th17 Responses via an IL-1-Dependent Pathway

PubMed Central

Anipindi, Varun C.; Dizzell, Sara E.; Nguyen, Philip V.; Shaler, Christopher R.; Chu, Derek K.; Jiménez-Saiz, Rodrigo; Liang, Hong; Swift, Stephanie; Nazli, Aisha; Kafka, Jessica K.; Bramson, Jonathan; Xing, Zhou; Jordana, Manel; Wan, Yonghong; Snider, Denis P.; Stampfli, Martin R.; Kaushic, Charu

2016-01-01

Clinical and experimental studies have shown that estradiol (E2) confers protection against HIV and other sexually transmitted infections. Here, we investigated the underlying mechanism. Better protection in E2-treated mice, immunized against genital HSV-2, coincided with earlier recruitment and higher proportions of Th1 and Th17 effector cells in the vagina post-challenge, compared to placebo-treated controls. Vaginal APCs isolated from E2-treated mice induced 10-fold higher Th17 and Th1 responses, compared to APCs from progesterone-treated, placebo-treated, and estradiol-receptor knockout mice in APC-T cell co-cultures. CD11c+ DCs in the vagina were the predominant APC population responsible for priming these Th17 responses, and a potent source of IL-6 and IL-1β, important factors for Th17 differentiation. Th17 responses were abrogated in APC-T cell co-cultures containing IL-1β KO, but not IL-6 KO vaginal DCs, showing that IL-1β is a critical factor for Th17 induction in the genital tract. E2 treatment in vivo directly induced high expression of IL-1β in vaginal DCs, and addition of IL-1β restored Th17 induction by IL-1β KO APCs in co-cultures. Finally, we examined the role of IL-17 in anti-HSV-2 memory T cell responses. IL-17 KO mice were more susceptible to intravaginal HSV-2 challenge, compared to WT controls, and vaginal DCs from these mice were defective at priming efficient Th1 responses in vitro, indicating that IL-17 is important for the generation of efficient anti-viral memory responses. We conclude that the genital mucosa has a unique microenvironment whereby E2 enhances CD4+ T cell anti-viral immunity by priming vaginal DCs to induce Th17 responses through an IL-1-dependent pathway. PMID:27148737

Immunological modes of pregnancy loss: inflammation, immune effectors, and stress.

PubMed

Kwak-Kim, Joanne; Bao, Shihua; Lee, Sung Ki; Kim, Joon Woo; Gilman-Sachs, Alice

2014-08-01

Inflammatory immune response plays a key role in reproductive failures such as multiple implantation failures (MIF), early pregnancy loss, and recurrent pregnancy losses (RPL). Cellular immune responses particularly mediated by natural killer (NK), and T cells are often dysregulated in these conditions. Excessive or inappropriate recruitment of peripheral blood NK cells to the uterus may lead to cytotoxic environment in utero, in which proliferation and differentiation of trophoblast is hampered. In addition, inadequate angiogenesis by uterine NK cells often leads to abnormal vascular development and blood flow patterns, which, in turn, leads to increased oxidative stress or ischemic changes in the invading trophoblast. T-cell abnormalities with increased Th1 and Th17 immunity, and decreased Th2 and T regulatory immune responses may play important roles in RPL and MIF. A possible role of stress in inflammatory immune response is also reviewed. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Soluble GARP has potent antiinflammatory and immunomodulatory impact on human CD4⁺ T cells.

PubMed

Hahn, Susanne A; Stahl, Heiko F; Becker, Christian; Correll, Anita; Schneider, Franz-Joseph; Tuettenberg, Andrea; Jonuleit, Helmut

2013-08-15

Glycoprotein A repetitions predominant (GARP) is expressed on the surface of activated human regulatory T cells (Treg) and regulates the bioavailability of transforming growth factor-β (TGF-β). GARP has been assumed to require membrane anchoring. To investigate the function of GARP in more detail, we generated a soluble GARP protein (sGARP) and analyzed its impact on differentiation and activation of human CD4⁺ T cells. We demonstrate that sGARP efficiently represses proliferation and differentiation of naïve CD4⁺ T cells into T effector cells. Exposure to sGARP induces Foxp3, decreases proliferation and represses interleukin (IL)-2 and interferon-γ production, resulting in differentiation of naïve T cells into induced Treg. This is associated with Smad2/3 phosphorylation and partially inhibited by blockade of TGF-β signaling. Furthermore, in the presence of the proinflammatory cytokines IL-6 and IL-23, sGARP facilitates the differentiation of naïve T cells into Th17 cells. More important, in a preclinical humanized mouse model of xenogeneic graft-versus-host disease (GVHD), sGARP prevents T cell-mediated destructive inflammation by enhancing Treg and inhibiting T effector cell activity. These results demonstrate a crucial role of sGARP in modulation of peripheral tolerance and T effector cell function, opening the possibility to use sGARP as a potent immunomodulator of inflammatory diseases including transplant rejection, autoimmunity, and allergy.

Invariant NKT cells inhibit development of the Th17 lineage

PubMed Central

Mars, Lennart T.; Araujo, Luiza; Kerschen, Philippe; Diem, Séverine; Bourgeois, Elvire; Van, Linh Pham; Carrié, Nadège; Dy, Michel; Liblau, Roland S.; Herbelin, André

2009-01-01

T cells differentiate into functionally distinct effector subsets in response to pathogen encounter. Cells of the innate immune system direct this process; CD1d-restricted invariant natural killer T (iNKT) cells, for example, can either promote or inhibit Th1 and Th2 responses. Recently, a new subset of CD4+ T helper cells, called Th17, was identified that is implicated in mucosal immunity and autoimmune disorders. To investigate the influence of iNKT cells on the differentiation of naïve T cells we used an adoptive transfer model of traceable antigen-specific CD4+ T cells. Transferred naïve CD25−CD62L+ CD4+ T cells were primed by antigen immunization of the recipient mice, permitting their expansion and Th17 differentiation. This study establishes that in vivo activation of iNKT cells during T-cell priming impedes the commitment of naïve T cells to the Th17 lineage. In vivo cytokine neutralization experiments revealed a role for IL-4, IL-10, and IFN-γ in the iNKT-cell-mediated regulation of T-cell lineage development. Moreover, by comparing IL-17 production by antigen-experienced T cells from unmanipulated wild-type mice and iNKT-cell-deficient mice, we demonstrate an enhanced Th17 response in mice lacking iNKT cells. This invigorated Th17 response reverts to physiological levels when iNKT cells are introduced into Jα18−/− mice by adoptive transfer, indicating that iNKT cells control the Th17 compartment at steady state. We conclude that iNKT cells play an important role in limiting development of the Th17 lineage and suggest that iNKT cells provide a natural barrier against Th17 responses. PMID:19325124

Insights into the role of Bcl6 in follicular Th cells using a new conditional mutant mouse model.

PubMed

Hollister, Kristin; Kusam, Saritha; Wu, Hao; Clegg, Ninah; Mondal, Arpita; Sawant, Deepali V; Dent, Alexander L

2013-10-01

The transcriptional repressor Bcl6 controls development of the follicular Th cell (T(FH)) lineage, but the precise mechanisms by which Bcl6 regulates this process are unclear. A model has been proposed whereby Bcl6 represses the differentiation of T cells into alternative effector lineages, thus favoring T(FH) cell differentiation. Analysis of T cell differentiation using Bcl6-deficient mice has been complicated by the strong proinflammatory phenotype of Bcl6-deficient myeloid cells. In this study, we report data from a novel mouse model where Bcl6 is conditionally deleted in T cells (Bcl6(fl/fl)Cre(CD4) mice). After immunization, programmed death -1 (PD-1)(high) T(FH) cells in Bcl6(fl/fl)Cre(CD4) mice are decreased >90% compared with control mice, and Ag-specific IgG is sharply reduced. Residual PD-1(high)CXCR5(+) T(FH) cells in Bcl6(fl/fl)Cre(CD4) mice show a significantly higher rate of apoptosis than do PD-1(high)CXCR5(+) T(FH) cells in control mice. Immunization of Bcl6(fl/fl)Cre(CD4) mice did not reveal enhanced differentiation into Th1, Th2, or Th17 lineages, although IL-10 expression by CD4 T cells was markedly elevated. Thus, T cell-extrinsic factors appear to promote the increased Th1, Th2, and Th17 responses in germline Bcl6-deficient mice. Furthermore, IL-10 may be a key target gene for Bcl6 in CD4 T cells, which enables Bcl6 to promote the T(FH) cell phenotype. Finally, our data reveal a novel mechanism for the role of Bcl6 in promoting T(FH) cell survival.

Bcl-2 Allows Effector and Memory CD8+ T Cells To Tolerate Higher Expression of Bim

PubMed Central

Kurtulus, Sema; Tripathi, Pulak; Moreno-Fernandez, Maria E.; Sholl, Allyson; Katz, Jonathan D.; Grimes, H. Leighton; Hildeman, David A.

2014-01-01

As acute infections resolve, most effector CD8+ T cells die, whereas some persist and become memory T cells. Recent work showed that subsets of effector CD8+ T cells, identified by reciprocal expression of killer cell lectin-like receptor G1 (KLRG1) and CD127, have different lifespans. Similar to previous reports, we found that effector CD8+ T cells reported to have a longer lifespan (i.e., KLRG1lowCD127high) have increased levels of Bcl-2 compared with their shorter-lived KLRG1highCD127low counterparts. Surprisingly, we found that these effector KLRG1lowCD127high CD8+ T cells also had increased levels of Bim compared with KLRG1highCD127low cells. Similar effects were observed in memory cells, in which CD8+ central memory T cells expressed higher levels of Bim and Bcl-2 than did CD8+ effector memory T cells. Using both pharmacologic and genetic approaches, we found that survival of both subsets of effector and memory CD8+ T cells required Bcl-2 to combat the proapoptotic activity of Bim. Interestingly, inhibition or absence of Bcl-2 led to significantly decreased expression of Bim in surviving effector and memory T cells. In addition, manipulation of Bcl-2 levels by IL-7 or IL-15 also affected expression of Bim in effector CD8+ T cells. Finally, we found that Bim levels were significantly increased in effector CD8+ T cells lacking Bax and Bak. Together, these data indicate that cells having the highest levels of Bim are selected against during contraction of the response and that Bcl-2 determines the level of Bim that effector and memory T cells can tolerate. PMID:21451108

Impairment of T-regulatory cells in cord blood of atopic mothers.

PubMed

Schaub, Bianca; Liu, Jing; Höppler, Sabine; Haug, Severine; Sattler, Christine; Lluis, Anna; Illi, Sabina; von Mutius, Erika

2008-06-01

Maternal atopy is a strong predictor for the development of childhood allergic diseases. The underlying mechanisms are ill defined, yet regulatory T (Treg) and T(H)17 cells may play a key role potentially shaping the early immune system toward a proallergic or antiallergic immune regulation. We examined T(H)1/T(H)2, Treg, and T(H)17 cell responses to innate (lipid A/peptidoglycan) and mitogen/adaptive (phytohemagglutinin/Dermatophagoides pteronyssinus 1) immune stimulation in cord blood from offspring of atopic/nonatopic mothers. Cord blood mononuclear cells from 161 healthy neonates (59% nonatopic, 41% atopic mothers) were investigated regarding Treg and T(H)17 cells (mRNA/surface markers), suppressive function, and proliferation/cytokine secretion. Cord blood from offspring of atopic mothers showed fewer innate-induced Treg cells (CD4(+)CD25(+)high), lower mRNA expression of associated markers (glucocorticoid-induced tumor necrosis factor receptor-related protein/lymphocyte activation gene 3; P < .05), and a trend toward lower Forkhead box transcription factor 3 (Foxp3) expression. Treg cell function was impaired in mitogen-induced suppression of T effector cells in cord blood of offspring from atopic mothers (P = .03). Furthermore, IL-10 and IFN-gamma secretion were decreased in innate-stimulated cord blood of offspring from atopic mothers (P = .04/.05). Innate-induced IL-17 was independent of maternal atopy and highly correlated with IL-13 secretion. In offspring of atopic mothers, Treg cell numbers, expression, and function were impaired at birth. T(H)17 cells were correlated with T(H)2 cells, independently of maternal atopy.

Silymarin inhibits ultraviolet radiation-induced immune suppression through DNA repair-dependent activation of dendritic cells and stimulation of effector T cells

PubMed Central

Vaid, Mudit; Prasad, Ram; Singh, Tripti; Elmets, Craig A.; Xu, Hui; Katiyar, Santosh K.

2013-01-01

Silymarin inhibits UVB-induced immunosuppression in mouse skin. To identify the molecular mechanisms underlying this effect, we used an adoptive transfer approach in which dendritic cells (DCs) from the draining lymph nodes of donor mice that had been UVB-exposed and sensitized to 2,4,-dinitrofluorobenzene (DNFB) were transferred into naïve recipient mice. The contact hypersensitivity (CHS) response of the recipient mice to DNFB was then measured. When DCs were obtained from UVB-exposed donor mice that were not treated with silymarin, the CHS response was suppressed confirming the role of DCs in the UVB-induced immunosuppression. Silymarin treatment of UVB-exposed donor mice relieved this suppression of the CHS response in the recipients. Silymarin treatment was associated with rapid repair of UVB-induced cyclobutane pyrimidine dimers (CPDs) in DCs and silymarin treatment did not prevent UV-induced immunosuppression in XPA-deficient mice which are unable to repair UV-induced DNA damage. The CHS response in mice receiving DCs from silymarin-treated UV-exposed donor mice also was associated with enhanced secretion of Th1-type cytokines and stimulation of T cells. Adoptive transfer of T cells revealed that transfer of either CD8+ or CD4+ cells from silymarin-treated, UVB-exposed donors resulted in enhancement of the CHS response. Cell culture study showed enhanced secretion of IL-2 and IFNγ by CD8+ T cells, and reduced secretion of Th2 cytokines by CD4+ cells, obtained from silymarin-treated UVB-exposed mice. These data suggest that DNA repair-dependent functional activation of DCs, a reduction in CD4+ regulatory T-cell activity, and stimulation of CD8+ effector T cells contribute to silymarin-mediated inhibition of UVB-induced immunosuppression. PMID:23395695

Th1 differentiation drives the accumulation of intravascular, non-protective CD4 T cells during tuberculosis

PubMed Central

Sallin, Michelle A.; Sakai, Shunsuke; Kauffman, Keith D.; Young, Howard A.; Zhu, Jinfang; Barber, Daniel L.

2017-01-01

SUMMARY Recent data indicate that the differentiation state of Th1 cells determines their protective capacity against tuberculosis. Therefore, we examined the role of Th1 polarizing factors in the generation of protective and non-protective subsets of Mtb-specific Th1 cells. We find IL-12/23p40 promotes Th1 cell expansion and maturation beyond the CD73+CXCR3+T-betdim stage, and T-bet prevents deviation of Th1 cells into Th17 cells. Nevertheless, IL-12/23p40 and T-bet are also essential for the production of a prominent subset of intravascular CX3CR1+KLRG1+ Th1 cells that persists poorly and can neither migrate into the lung parenchyma nor control Mtb growth. Furthermore, T-bet suppresses development of CD69+CD103+ tissue resident phenotype effectors in lung. In contrast, Th1 cell-derived IFNγ inhibits the accumulation of intravascular CX3CR1+KLRG1+ Th1 cells. Thus, although IL-12 and T-bet are essential host survival factors, they simultaneously oppose lung CD4 T cell responses at several levels, demonstrating the dual nature of Th1 polarization in tuberculosis. PMID:28355562

Antigen-Specific Induction of Osteopontin Contributes to the Chronification of Allergic Contact Dermatitis

PubMed Central

Seier, Anne M.; Renkl, Andreas C.; Schulz, Guido; Uebele, Tanja; Sindrilaru, Anca; Iben, Sebastian; Liaw, Lucy; Kon, Shigeyuki; Uede, Toshimitsu; Weiss, Johannes M.

2010-01-01

Allergic contact dermatitis is a T cell-mediated immune response, which in its relapsing chronic form is of high socioeconomic impact. The phosphoglycoprotein osteopontin (OPN) has chemotactic and Th1 cytokine functions and in various models is essential for robust T cell-mediated immunity. Here we demonstrate that OPN is abundantly expressed by both effector T cells and keratinocytes in allergic contact dermatitis lesions. T cells from nickel-allergic donors secrete high levels of OPN following antigen-specific stimulation. OPN may substitute for missing IFN-γ secretion in T effector cells because low IFN-γ-producing T cell clones secrete high levels of OPN, and OPN down-modulates their interleukin-4 expression. Furthermore, interferon-γ from T effector cells augments OPN in allergic contact dermatitis by inducing OPN in keratinocytes, which in turn polarizes dendritic cells and attracts inflammatory cells. In the murine contact hypersensitivity (CHS) model for allergic contact dermatitis, OPN is strongly induced in antigen-specific proliferating T cells, and OPN null mice display a reduced chronic CHS inflammatory response due to a decreased influx of effector T cells. Importantly, because of its function for chronic allergic contact dermatitis, OPN may well be a therapeutic target, because anti-OPN antibody treatment in part suppresses established chronic CHS. PMID:20008129

Identification of Pertussis-Specific Effector Memory T Cells in Preschool Children

PubMed Central

Schure, Rose-Minke; Öztürk, Kemal; Berbers, Guy; Sanders, Elisabeth; van Twillert, Inonge; Carollo, Maria; Mascart, Françoise; Ausiello, Clara M.; van Els, Cecile A. C. M.; Smits, Kaat; Buisman, Anne-Marie

2015-01-01

Whooping cough remains a problem despite vaccination, and worldwide resurgence of pertussis is evident. Since cellular immunity plays a role in long-term protection against pertussis, we studied pertussis-specific T-cell responses. Around the time of the preschool acellular pertussis (aP) booster dose at 4 years of age, T-cell memory responses were compared in children who were primed during infancy with either a whole-cell pertussis (wP) or an aP vaccine. Peripheral blood mononuclear cells (PBMCs) were isolated and stimulated with pertussis vaccine antigens for 5 days. T cells were characterized by flow-based analysis of carboxyfluorescein succinimidyl ester (CFSE) dilution and CD4, CD3, CD45RA, CCR7, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α) expression. Before the aP preschool booster vaccination, both the proliferated pertussis toxin (PT)-specific CD4+ and CD8+ T-cell fractions (CFSEdim) were higher in aP- than in wP-primed children. Post-booster vaccination, more pertussis-specific CD4+ effector memory cells (CD45RA− CCR7−) were induced in aP-primed children than in those primed with wP. The booster vaccination did not appear to significantly affect the T-cell memory subsets and functionality in aP-primed or wP-primed children. Although the percentages of Th1 cytokine-producing cells were alike in aP- and wP-primed children pre-booster vaccination, aP-primed children produced more Th1 cytokines due to higher numbers of proliferated pertussis-specific effector memory cells. At present, infant vaccinations with four aP vaccines in the first year of life result in pertussis-specific CD4+ and CD8+ effector memory T-cell responses that persist in children until 4 years of age and are higher than those in wP-primed children. The booster at 4 years of age is therefore questionable; this may be postponed to 6 years of age. PMID:25787136

MicroRNA profiling of the murine hematopoietic system

PubMed Central

Monticelli, Silvia; Ansel, K Mark; Xiao, Changchun; Socci, Nicholas D; Krichevsky, Anna M; Thai, To-Ha; Rajewsky, Nikolaus; Marks, Debora S; Sander, Chris; Rajewsky, Klaus; Rao, Anjana; Kosik, Kenneth S

2005-01-01

Background MicroRNAs (miRNAs) are a class of recently discovered noncoding RNA genes that post-transcriptionally regulate gene expression. It is becoming clear that miRNAs play an important role in the regulation of gene expression during development. However, in mammals, expression data are principally based on whole tissue analysis and are still very incomplete. Results We used oligonucleotide arrays to analyze miRNA expression in the murine hematopoietic system. Complementary oligonucleotides capable of hybridizing to 181 miRNAs were immobilized on a membrane and probed with radiolabeled RNA derived from low molecular weight fractions of total RNA from several different hematopoietic and neuronal cells. This method allowed us to analyze cell type-specific patterns of miRNA expression and to identify miRNAs that might be important for cell lineage specification and/or cell effector functions. Conclusion This is the first report of systematic miRNA gene profiling in cells of the hematopoietic system. As expected, miRNA expression patterns were very different between hematopoietic and non-hematopoietic cells, with further subtle differences observed within the hematopoietic group. Interestingly, the most pronounced similarities were observed among fully differentiated effector cells (Th1 and Th2 lymphocytes and mast cells) and precursors at comparable stages of differentiation (double negative thymocytes and pro-B cells), suggesting that in addition to regulating the process of commitment to particular cellular lineages, miRNAs might have an important general role in the mechanism of cell differentiation and maintenance of cell identity. PMID:16086853

Follicular helper T cells in immunity and systemic autoimmunity.

PubMed

Craft, Joseph E

2012-05-01

Follicular helper T (T(FH)) cells are essential for B-cell maturation and immunoglobulin production after immunization with thymus-dependent antigens. Nevertheless, the development and function of T(FH) cells have been less clearly defined than classic CD4(+) effector T-cell subsets, including T-helper-1 (T(H)1), T(H)2 and T(H)17 cells. As such, our understanding of the genesis of T(FH) cells in humans and their role in the development of autoimmunity remains incomplete. However, evidence from animal models of systemic lupus erythematosus (SLE) and patients with systemic autoimmune diseases suggests that these cells are necessary for pathogenic autoantibody production, in a manner analogous to their role in promotion of B-cell maturation during normal immune responses. In this Review, I discuss the findings that have increased our knowledge of T(FH)-cell development and function in normal and aberrant immune responses. Such information might improve our understanding of autoimmune diseases, such as SLE, and highlights the potential of T(FH) cells as therapeutic targets in these diseases.

Negative regulation of NKG2D expression by IL-4 in memory CD8 T cells.

PubMed

Ventre, Erwan; Brinza, Lilia; Schicklin, Stephane; Mafille, Julien; Coupet, Charles-Antoine; Marçais, Antoine; Djebali, Sophia; Jubin, Virginie; Walzer, Thierry; Marvel, Jacqueline

2012-10-01

IL-4 is one of the main cytokines produced during Th2-inducing pathologies. This cytokine has been shown to affect a number of immune processes such as Th differentiation and innate immune responses. However, the impact of IL-4 on CD8 T cell responses remains unclear. In this study, we analyzed the effects of IL-4 on global gene expression profiles of Ag-induced memory CD8 T cells in the mouse. Gene ontology analysis of this signature revealed that IL-4 regulated most importantly genes associated with immune responses. Moreover, this IL-4 signature overlapped with the set of genes preferentially expressed by memory CD8 T cells over naive CD8 T cells. In particular, IL-4 downregulated in vitro and in vivo in a STAT6-dependent manner the memory-specific expression of NKG2D, thereby increasing the activation threshold of memory CD8 T cells. Furthermore, IL-4 impaired activation of memory cells as well as their differentiation into effector cells. This phenomenon could have an important clinical relevance as patients affected by Th2 pathologies such as parasitic infections or atopic dermatitis often suffer from viral-induced complications possibly linked to inefficient CD8 T cell responses.

Phenotype, effector function, and tissue localization of PD-1-expressing human follicular helper T cell subsets

PubMed Central

2011-01-01

Background It is well established that PD-1 is expressed by follicular T cells but its function in regulation of human T helper cells has been unclear. We investigated the expression modality and function of PD-1 expressed by human T cells specialized in helping B cells. Results We found that PD-1-expressing T cells are heterogeneous in PD-1 expression. We identified three different PD-1-expressing memory T cell subsets (i.e. PD-1low (+), PD-1medium (++), and PD-1high (+++) cells). PD-1+++ T cells expressed CXCR5 and CXCR4 and were localized in the rim of germinal centers. PD-1+ or PD-1++ cells expressed CCR7 and were present mainly in the T cell area or other parts of the B cell follicles. Utilizing a novel antigen density-dependent magnetic sorting (ADD-MS) method, we isolated the three T cell subsets for functional characterization. The germinal center-located PD-1+++ T cells were most efficient in helping B cells and in producing IL-21 and CXCL13. Other PD-1-expressing T cells, enriched with Th1 and Th17 cells, were less efficient than PD-1+++ T cells in these capacities. PD-1+++ T cells highly expressed Ki-67 and therefore appear active in cell activation and proliferation in vivo. IL-2 is a cytokine important for proliferation and survival of the PD-1+++ T cells. In contrast, IL-21, while a major effector cytokine produced by the PD-1-expressing T helper cells, had no function in generation, survival, or proliferation of the PD-1-expressing helper T cells at least in vitro. PD-1 triggering has a suppressive effect on the proliferation and B cell-helping function of PD-1+++ germinal center T cells. Conclusion Our results revealed the phenotype and effector function of PD-1-expressing T helper cell subsets and indicate that PD-1 restrains the B cell-helping function of germinal center-localized T cells to prevent excessive antibody response. PMID:21914188

IL-23 is critical in the induction but not in the effector phase of experimental autoimmune encephalomyelitis.

PubMed

Thakker, Paresh; Leach, Michael W; Kuang, Wen; Benoit, Stephen E; Leonard, John P; Marusic, Suzana

2007-02-15

Experimental autoimmune encephalomyelitis (EAE), a T cell-mediated inflammatory disease of the CNS, is a rodent model of human multiple sclerosis. IL-23 is one of the critical cytokines in EAE development and is currently believed to be involved in the maintenance of encephalitogenic responses during the tissue damage effector phase of the disease. In this study, we show that encephalitogenic T cells from myelin oligodendrocyte glycopeptide (MOG)-immunized wild-type (WT) mice caused indistinguishable disease when adoptively transferred to WT or IL-23-deficient (p19 knockout (KO)) recipient mice, demonstrating that once encephalitogenic cells have been generated, EAE can develop in the complete absence of IL-23. Furthermore, IL-12/23 double-deficient (p35/p19 double KO) recipient mice developed EAE that was indistinguishable from WT recipients, indicating that IL-12 did not compensate for IL-23 deficiency during the effector phase of EAE. In contrast, MOG-specific T cells from p19KO mice induced EAE with delayed onset and much lower severity when transferred to WT recipient mice as compared with the EAE that was induced by cells from WT controls. MOG-specific T cells from p19KO mice were highly deficient in the production of IFN-gamma, IL-17A, and TNF, indicating that IL-23 plays a critical role in development of encephalitogenic T cells and facilitates the development of T cells toward both Th1 and Th17 pathways.

Role of IL-22– and TNF-α–Producing Th22 Cells in Uveitis Patients with Behçet’s Disease

PubMed Central

Kawazoe, Yuko; Imai, Ayano; Kawaguchi, Tatsushi; Horie, Shintaro; Keino, Hiroshi; Takahashi, Masayo; Mochizuki, Manabu

2013-01-01

Behçet’s disease is a systemic inflammatory disorder with recurrent episodes of oral ulceration, skin lesions, genital ulceration, and intraocular inflammation (uveitis). The intraocular inflammation is strictly associated with Th effector cells. IL-22 is a member of the IL-10 cytokine family that is involved in inflammatory processes. Recently, Th22 cells were identified as a Th cell population that produces IL-22 and TNF-α and are distinct from Th1, Th2, and Th17 cells. In this study, we established Th22-type T cell clones from ocular samples taken from Behçet’s disease patients with active uveitis. These clones produced large amounts of IL-22 and TNF-α but not the Th1 cytokine IFN-γ and the Th17 cytokine IL-17. CD4+ T cells from the peripheral blood of Behçet’s disease patients differentiated into Th22 cells in the presence of IL-6 and TNF-α in vitro. The polarized Th22 cell lines produced large amounts of IL-22, and the polarized Th1 and Th17 cells also produced IL-22. In the presence of anti–TNF-α– and anti–IL-6–blocking Abs, Behçet’s disease Th22-type T cells failed to produce IL-22. In addition, infliximab-pretreated Th22 cells and Th22-type ocular T cells produced less IL-22 and TNF-α. Moreover, IL-22–producing T cells were isolated from mice with experimental autoimmune uveitis, an animal model of Behçet’s disease, and the intraocular T cells from uveitis models produced large amounts of IL-22 in the presence of retinal Ags. Our results suggest that inflammatory cytokines IL-22 and TNF-α may play a key role in the ocular immune response in Behçet’s disease. PMID:23630362

Memory CD8+ T Cells Protect Dendritic Cells from CTL Killing1

PubMed Central

Watchmaker, Payal B.; Urban, Julie A.; Berk, Erik; Nakamura, Yutaro; Mailliard, Robbie B.; Watkins, Simon C.; van Ham, S. Marieke; Kalinski, Pawel

2010-01-01

CD8+ T cells have been shown to be capable of either suppressing or promoting immune responses. To reconcile these contrasting regulatory functions, we compared the ability of human effector and memory CD8+ T cells to regulate survival and functions of dendritic cells (DC). We report that, in sharp contrast to the effector cells (CTLs) that kill DCs in a granzyme B- and perforin-dependent mechanism, memory CD8+ T cells enhance the ability of DCs to produce IL-12 and to induce functional Th1 and CTL responses in naive CD4+ and CD8+ T cell populations. Moreover, memory CD8+ T cells that release the DC-activating factor TNF-α before the release of cytotoxic granules induce DC expression of an endogenous granzyme B inhibitor PI-9 and protect DCs from CTL killing with similar efficacy as CD4+ Th cells. The currently identified DC-protective function of memory CD8+ T cells helps to explain the phenomenon of CD8+ T cell memory, reduced dependence of recall responses on CD4+ T cell help, and the importance of delayed administration of booster doses of vaccines for the optimal outcome of immunization. PMID:18322193

Dendritic cells in transplantation and immune-based therapies.

PubMed

Young, James W; Merad, Miriam; Hart, Derek N J

2007-01-01

Dendritic cells (DCs) are specialized, bone marrow-derived leukocytes critical to the onset of both innate and adaptive immunity. The divisions of labor among distinct human DC subtypes achieve the most effective balance between steady-state tolerance and the induction of innate and adaptive immunity against pathogens, tumors, and other insults. Maintenance of tolerance in the steady state is an active process involving resting or semimature DCs. Breakdowns in this homeostasis can result in autoimmunity. Perturbation of the steady state should first lead to the onset of innate immunity mediated by rapid responders in the form of plasmacytoid and monocyte-derived DC stimulators and natural killer (NK) and NK T-cell responders. These innate effectors then provide additional inflammatory cytokines, including interferon-gamma, which support the activation and maturation of resident and circulating populations of DCs. These are critical to the onset and expansion of adaptive immunity, including Th1, Th2, and cytotoxic T-lymphocyte responses. Rodent models are now revealing important data about distinct DC precursors, homeostasis of tissue-resident DCs, and DC turnover in response to inflammation and pathological conditions like graft-versus-host disease. The use of defined DC subtypes to stimulate both innate and adaptive immunity, either in combination or in a prime-boost vaccine sequence, may prove most useful clinically by harnessing both effector cell compartments.

Quantitative immunophenotypic analysis of antigen-presenting cells involved in ectromelia virus antigen presentation in BALB/c and C57BL/6 mice.

PubMed

Szulc-Dąbrowska, Lidia; Gieryńska, Małgorzata; Boratyńska-Jasińska, Anna; Martyniszyn, Lech; Winnicka, Anna; Niemiałtowski, Marek G

2013-08-01

During mousepox in resistant (C57BL/6) or susceptible (BALB/c) strains of mice, stimulation of Th1 or Th2 cytokine immune response, respectively, is observed. Because mechanisms of different polarization of T cells remain elusive, in this study, we quantitatively assessed the phenotype of antigen-presenting cells (APCs) involved in ectromelia virus (ECTV) antigen presentation and cluster formation with effector cells in secondary lymphoid organs of BALB/c and C57BL/6 mice. We showed that both strains of mice display similar dynamics and kinetics of viral antigen presentation by CD11c(+) , CD11b(+) , and CD19(+) cells. CD11c(+) and CD11b(+) cells highly participated in viral antigen presentation during all stages of mousepox, whereas CD19(+) cells presented viral peptides later in infection. The main population of dendritic cells (DCs) engaged in ECTV antigen presentation and cell junction formation with effector cells was a population of myeloid CD11b(+) DCs (mDCs). We suggest that, on the one hand, ECTV may differentially affect the functions of APCs depending on the strain of mice. On the other hand, we suggest that some types of APCs, such as mDCs or other DCs subsets, have different abilities to direct the shape of immune response depending on the host resistance to mousepox. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Increase in activated Treg in TIL in lung cancer and in vitro depletion of Treg by ADCC using an antihuman CCR4 mAb (KM2760).

PubMed

Kurose, Koji; Ohue, Yoshihiro; Sato, Eiichi; Yamauchi, Akira; Eikawa, Shingo; Isobe, Midori; Nishio, Yumi; Uenaka, Akiko; Oka, Mikio; Nakayama, Eiichi

2015-01-01

Tregs infiltrate tumors and inhibit immune responses against them. We investigated subpopulations of Foxp3 CD4 T cells previously defined by Miyara et al. (Immunity 30, 899-911, 2009) in peripheral blood mononuclear cells (PBMCs) and tumor infiltrating lymphocytes (TILs) in lung cancer. We also showed that Tregs in healthy donors that express CCR4 could be efficiently eliminated in vitro by cotreatment with antihuman (h) CCR4 mAb (KM2760) and NK cells. In lung cancer, the number of activated/effector Tregs and non-Tregs, but not resting/naive Tregs, was increased in TILs compared with the number of those cells in PBMCs. The non-Treg population contained Th2 and Th17. CCR4 expression on activated/effector Tregs and non-Tregs in TILs was down-regulated compared with that on those cells in PBMCs. Chemokinetic migration of CD25 CD4 T cells containing the Treg population sorted from the PBMCs of healthy donors to CCL22/MDC was abrogated by pretreatment with anti-hCCR4 mAb (KM2760). The inhibitory activity of CD25 CD127 CD4 Tregs on the proliferative response of CD4 and CD8 T cells stimulated with anti-CD3/CD28 coated beads was abrogated by adding an anti-hCCR4 mAb (KM2760) and CD56 NK cells to the culture. The findings suggested the CCR4 on activated/effector Tregs and non-Tregs was functionally involved in the chemokinetic migration and accumulation of those cells to the tumor site. In vitro findings of efficient elimination of Tregs may give the basis for implementation of a clinical trial to investigate Treg depletion by administration of an anti-hCCR4 mAb to solid cancer patients.

Virus-like particle vaccine primes immune responses preventing inactivated-virus vaccine-enhanced disease against respiratory syncytial virus.

PubMed

Hwang, Hye Suk; Lee, Young-Tae; Kim, Ki-Hye; Ko, Eun-Ju; Lee, Youri; Kwon, Young-Man; Kang, Sang-Moo

2017-11-01

Formalin inactivated respiratory syncytial virus (FI-RSV) vaccination caused vaccine-enhanced respiratory disease (ERD) upon exposure to RSV in children. Virus-like particles presenting RSV F fusion protein (F VLP) are known to increase T helper type-1 (Th1) immune responses and avoid ERD in animal models. We hypothesized that F VLP would prime immune responses preventing ERD upon subsequent exposure to ERD-prone FI-RSV. Here, we demonstrated that heterologous F VLP priming and FI-RSV boosting of mice prevented FI-RSV vaccine-enhanced lung inflammation and eosinophilia upon RSV challenge. F VLP priming redirected pulmonary T cells toward effector CD8 T cells producing Th1 cytokines and significantly suppressed pulmonary Th2 cytokines. This study suggests that RSV F VLP priming would modulate and shift immune responses to subsequent exposure to ERD-prone FI-RSV vaccine and RSV infection, suppressing Th2 immune-mediated pulmonary histopathology and eosinophilia. Copyright © 2017. Published by Elsevier Inc.

Immunoregulatory effects on T lymphocytes by human mesenchymal stromal cells isolated from bone marrow, amniotic fluid, and placenta.

PubMed

Mareschi, Katia; Castiglia, Sara; Sanavio, Fiorella; Rustichelli, Deborah; Muraro, Michela; Defedele, Davide; Bergallo, Massimiliano; Fagioli, Franca

2016-02-01

Mesenchymal stromal cells (MSCs) are a promising tool in cell therapies because of their multipotent, bystander, and immunomodulatory properties. Although bone marrow represents the main source of MSCs, there remains a need to identify a stem cell source that is safe and easily accessible and yields large numbers of cells without provoking debates over ethics. In this study, MSCs isolated from amniotic fluid and placenta were compared with bone marrow MSCs. Their immunomodulatory properties were studied in total activated T cells (peripheral blood mononuclear cells) stimulated with phytohemagglutinin (PHA-PBMCs). In particular, an in vitro co-culture system was established to study: (i) the effect on T-lymphocyte proliferation; (ii) the presence of T regulatory lymphocytes (Treg); (iii) the immunophenotype of various T subsets (Th1 and Th2 naïve, memory, effector lymphocytes); (iv) cytokine release and master gene expression to verify Th1, Th2, and Th17 polarization; and (v) IDO production. Under all co-culture conditions with PHA-PBMCs and MSCs (independently of tissue origin), data revealed: (i) T proliferation inhibition; (ii) increase in naïve T and decrease in memory T cells; (iii) increase in T regulatory lymphocytes; (iv) strong Th2 polarization associated with increased interleukin-10 and interleukin-4 levels, Th1 inhibition (significant decreases in interleukin-2, tumor necrosis factor-α, interferon-γ, and interleukin-12) and Th17 induction (production of high concentrations of interleukins-6 and -17); (v) indoleamine-2,3-dioxygenase mRNA induction in MSCs co-cultured with PHA-PBMCs. AF-MSCs had a more potent immunomodulatory effect on T cells than BM-MSCs, only slightly higher than that of placenta MSCs. This study indicates that MSCs isolated from fetal tissues may be considered a good alternative to BM-MSCs for clinical applications. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

HIV-Infected Children Have Elevated Levels of PD-1+ Memory CD4 T Cells With Low Proliferative Capacity and High Inflammatory Cytokine Effector Functions.

PubMed

Foldi, Julia; Kozhaya, Lina; McCarty, Bret; Mwamzuka, Mussa; Marshed, Fatma; Ilmet, Tiina; Kilberg, Max; Kravietz, Adam; Ahmed, Aabid; Borkowsky, William; Unutmaz, Derya; Khaitan, Alka

2017-09-15

During human immunodeficiency virus (HIV) disease, chronic immune activation leads to T-cell exhaustion. PD-1 identifies "exhausted" CD8 T cells with impaired HIV-specific effector functions, but its role on CD4 T cells and in HIV-infected children is poorly understood. In a Kenyan cohort of vertically HIV-infected children, we measured PD-1+ CD4 T-cell frequencies and phenotype by flow cytometry and their correlation with HIV disease progression and immune activation. Second, in vitro CD4 T-cell proliferative and cytokine responses to HIV-specific and -nonspecific stimuli were assessed with and without PD-1 blockade. HIV-infected children have increased frequencies of PD-1+ memory CD4 T cells that fail to normalize with antiretroviral treatment. These cells are comprised of central and effector memory subsets and correlate with HIV disease progression, measured by viral load, CD4 percentage, CD4:CD8 T-cell ratio, and immune activation. Last, PD-1+ CD4 T cells predict impaired proliferative potential yet preferentially secrete the Th1 and Th17 cytokines interferon-γ and interleukin 17A, and are unresponsive to in vitro PD-1 blockade. This study highlights differences in PD-1+ CD4 T-cell memory phenotype and response to blockade between HIV-infected children and adults, with implications for potential immune checkpoint therapies. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Heterogeneity of Human CD4(+) T Cells Against Microbes.

PubMed

Sallusto, Federica

2016-05-20

CD4(+) T helper (Th) cells play a central role in the adaptive immune response by providing help to B cells and cytotoxic T cells and by releasing different types of cytokines in tissues to mediate protection against a wide range of pathogenic microorganisms. These functions are performed by different types of Th cells endowed with distinct migratory capacities and effector functions. Here we discuss how studies of the human T cell response to microbes have advanced our understanding of Th cell functional heterogeneity, in particular with the discovery of a distinct Th1 subset involved in the response to Mycobacteria and the characterization of two types of Th17 cells specific for extracellular bacteria or fungi. We also review new approaches to dissect at the clonal level the human CD4(+) T cell response induced by pathogens or vaccines that have revealed an unexpected degree of intraclonal diversification and propose a progressive and selective model of CD4(+) T cell differentiation.

High levels of type 2 cytokine-producing cells in chronic fatigue syndrome.

PubMed

Skowera, A; Cleare, A; Blair, D; Bevis, L; Wessely, S C; Peakman, M

2004-02-01

The aetiology of chronic fatigue syndrome (CFS) is not known. However, it has been suggested that CFS may be associated with underlying immune activation resulting in a Th2-type response. We measured intracellular production of interferon (IFN)-gamma and interleukin (IL)-2; type 1 cytokines), IL-4 (type 2) and IL-10 (regulatory) by both polyclonally stimulated and non-stimulated CD4 and CD8 lymphocytes from patients with CFS and control subjects by flow cytometry. After polyclonal activation we found evidence of a significant bias towards Th2- and Tc2-type immune responses in CFS compared to controls. In contrast, levels of IFN-gamma, IL-2 and IL-10-producing cells were similar in both study groups. Non-stimulated cultures revealed significantly higher levels of T cells producing IFN-gamma or IL-4 in CFS patients. Concluding, we show evidence for an effector memory cell bias towards type 2 responsiveness in patients with CFS, as well as ongoing type 0 immune activation in unstimulated cultures of peripheral blood cells.

High levels of type 2 cytokine-producing cells in chronic fatigue syndrome

PubMed Central

SKOWERA, A; CLEARE, A; BLAIR, D; BEVIS, L; WESSELY, S C; PEAKMAN, M

2004-01-01

The aetiology of chronic fatigue syndrome (CFS) is not known. However, it has been suggested that CFS may be associated with underlying immune activation resulting in a Th2-type response. We measured intracellular production of interferon (IFN)-γ and interleukin (IL)-2; type 1 cytokines), IL-4 (type 2) and IL-10 (regulatory) by both polyclonally stimulated and non-stimulated CD4 and CD8 lymphocytes from patients with CFS and control subjects by flow cytometry. After polyclonal activation we found evidence of a significant bias towards Th2- and Tc2-type immune responses in CFS compared to controls. In contrast, levels of IFN-γ, IL-2 and IL-10-producing cells were similar in both study groups. Non-stimulated cultures revealed significantly higher levels of T cells producing IFN-γ or IL-4 in CFS patients. Concluding, we show evidence for an effector memory cell bias towards type 2 responsiveness in patients with CFS, as well as ongoing type 0 immune activation in unstimulated cultures of peripheral blood cells. PMID:14738459

Suppression of allergic airway inflammation in a mouse model by Der p2 recombined BCG.

PubMed

Ou-Yang, Hai-Feng; Hu, Xing-Bin; Ti, Xin-Yu; Shi, Jie-Ran; Li, Shu-Jun; Qi, Hao-Wen; Wu, Chang-Gui

2009-09-01

Allergic asthma is a chronic inflammatory disease mediated by T helper (Th)2 cell immune responses. Currently, immunotherapies based on both immune deviation and immune suppression, including the development of recombinant mycobacteria as immunoregulatory vaccines, are attractive treatment strategies for asthma. In our previous studies, we created a genetically recombinant form of bacille Calmette-Guerin (rBCG) that expressed Der p2 of house dust mites and established that it induced a shift from a Th2 response to a Th1 response in naive mice. However, it is unclear whether rBCG could suppress allergic airway inflammation in a mouse model. In this article we report that rBCG dramatically inhibited airway inflammation, eosinophilia, mucus production and mast cell degranulation in allergic mice. Analysis of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) levels in bronchoalveolar lavage fluid (BALF) and lung tissue revealed that the suppression was associated with a shift from a Th2 response to a Th1 response. At the same time, rBCG induced a CD4(+) CD25(+) Foxp3(+) T-cell subtype that could suppress the proliferation of Th2 effector cells in vitro in an antigen-specific manner. Moreover, suppression of CD4(+) CD25(+) T cells could be adoptively transferred. Thus, our results demonstrate that rBCG induces both generic and specific immune responses. The generic immune response is associated with a shift from a Th2 to a Th1 cytokine response, whereas the specific immune response against Der p2 appears to be related to the expansion of transforming growth factor-beta (TGF-beta)-producing CD4(+) CD25(+) Foxp3(+) regulatory T cells. rBCG can suppress asthmatic airway inflammation through both immune deviation and immune suppression and may be a feasible, efficient immunotherapy for asthma.

GENERATION OF CYTOTOXIC LYMPHOCYTES IN MIXED LYMPHOCYTE REACTIONS

PubMed Central

Forman, James; Möller, Göran

1973-01-01

Generation of cytotoxic effector cells by a unidirectional mixed lymphocyte reaction (MLR) in the mouse H-2 system was studied using labeled YAC (H-2a) leukemia cells as targets. The responding effector cell displayed a specific cytotoxic effect against target cells of the same H-2 genotype as the stimulating cell population. Killing of syngeneic H-2 cells was not observed, even when the labeled target cells were "innocent bystanders" in cultures where specific target cells were reintroduced. Similar results were found with spleen cells taken from mice sensitized in vivo 7 days earlier. The effector cell was not an adherent cell and was not activated by supernatants from MLR. The supernatants were not cytotoxic by themselves. When concanavalin A or phytohemagglutinin was added to the cytotoxic test system, target and effector cells were agglutinated. Under these conditions, killing of H-2a target cells was observed in mixed cultures where H-2a lymphocytes were also the effector cells. These findings indicate that specifically activated, probably thymus-derived lymphocytes, can kill nonspecifically once they have been activated and providing there is close contact between effector and target cells. Thus, specificity of T cell killing appears to be restricted to recognition and subsequent binding to the targets, the actual effector phase being nonspecific. PMID:4269560

T cell-intrinsic requirement for NF-kappa B induction in postdifferentiation IFN-gamma production and clonal expansion in a Th1 response.

PubMed

Corn, Radiah A; Aronica, Mark A; Zhang, Fuping; Tong, Yingkai; Stanley, Sarah A; Kim, Se Ryoung Agnes; Stephenson, Linda; Enerson, Ben; McCarthy, Susan; Mora, Ana; Boothby, Mark

2003-08-15

NF-kappaB/Rel transcription factors are linked to innate immune responses and APC activation. Whether and how the induction of NF-kappaB signaling in normal CD4(+) T cells regulates effector function are not well-understood. The liberation of NF-kappaB dimers from inhibitors of kappaB (IkappaBs) constitutes a central checkpoint for physiologic regulation of most forms of NF-kappaB. To investigate the role of NF-kappaB induction in effector T cell responses, we targeted inhibition of the NF-kappaB/Rel pathway specifically to T cells. The Th1 response in vivo is dramatically weakened when T cells defective in their NF-kappaB induction (referred to as IkappaBalpha(DeltaN) transgenic cells) are activated by a normal APC population. Analyses in vivo, and IL-12-supplemented T cell cultures in vitro, reveal that the mechanism underlying this T cell-intrinsic requirement for NF-kappaB involves activation of the IFN-gamma gene in addition to clonal expansion efficiency. The role of NF-kappaB in IFN-gamma gene expression includes a modest decrease in Stat4 activation, T box expressed in T cell levels, and differentiation efficiency along with a more prominent postdifferentiation step. Further, induced expression of Bcl-3, a trans-activating IkappaB-like protein, is decreased in T cells as a consequence of NF-kappaB inhibition. Together, these findings indicate that NF-kappaB induction in T cells regulates efficient clonal expansion, Th1 differentiation, and IFN-gamma production by Th1 lymphocytes at a control point downstream from differentiation.

Histone Acetylation at the Ifng Promoter in Tolerized CD4 Cells Is Associated with Increased IFN-γ Expression during Subsequent Immunization to the Same Antigen1

PubMed Central

Long, Meixiao; Slaiby, Aaron M.; Wu, Shuang; Hagymasi, Adam T.; Mihalyo, Marianne A.; Bandyopadhyay, Suman; Vella, Anthony T.; Adler, Adam J.

2010-01-01

When naive CD4+ Th cells encounter cognate pathogen-derived Ags they expand and develop the capacity to express the appropriate effector cytokines for neutralizing the pathogen. Central to this differentiation process are epigenetic modifications within the effector cytokine genes that allow accessibility to the transcriptional machinery. In contrast, when mature self-reactive CD4 cells encounter their cognate epitopes in the periphery they generally undergo a process of tolerization in which they become hyporesponsive/anergic to antigenic stimulation. In the current study, we used a TCR transgenic adoptive transfer system to demonstrate that in a dose-dependent manner parenchymal self-Ag programs cognate naive CD4 cells to acetylate histones bound to the promoter region of the Ifng gene (which encodes the signature Th1 effector cytokine) during peripheral tolerization. Although the Ifng gene gains transcriptional competence, these tolerized CD4 cells fail to express substantial amounts of IFN-γ in response to antigenic stimulation apparently because a blockage in TCR-mediated signaling also develops. Nevertheless, responsiveness to antigenic stimulation is partially restored when self-Ag-tolerized CD4 cells are retransferred into mice infected with a virus expressing the same Ag. Additionally, there is preferential boosting in the ability of these CD4 cells to express IFN-γ relative to other cytokines with expression that also becomes impaired. Taken together, these results suggest that epigenetic modification of the Ifng locus during peripheral CD4 cell tolerization might allow for preferential expression of IFN-γ during recovery from tolerance. PMID:17947638

CryJ-LAMP DNA Vaccines for Japanese Red Cedar Allergy Induce Robust Th1-Type Immune Responses in Murine Model

PubMed Central

Connolly, Michael; Marketon, Anthony

2016-01-01

Allergies caused by Japanese Red Cedar (JRC) pollen affect up to a third of Japanese people, necessitating development of an effective therapeutic. We utilized the lysosomal targeting property of lysosomal-associated membrane protein-1 (LAMP-1) to make DNA vaccines that encode LAMP-1 and the sequences of immunodominant allergen CryJ1 or CryJ2 from the JRC pollen. This novel strategy is designed to skew the CD4 T cell responses to the target allergens towards a nonallergenic Th1 response. CryJ1-LAMP and CryJ2-LAMP were administrated to BALB/c mice and antigen-specific Th1-type IgG2a and Th2-type IgG1 antibodies, as well as IgE antibodies, were assayed longitudinally. We also isolated different T cell populations from immunized mice and adoptively transferred them into naïve mice followed by CryJ1/CryJ2 protein boosts. We demonstrated that CryJ-LAMP immunized mice produce high levels of IFN-γ and anti-CryJ1 or anti-CryJ2 IgG2a antibodies and low levels of IgE antibodies, suggesting that a Th1 response was induced. In addition, we found that CD4+ T cells are the immunological effectors of DNA vaccination in this allergy model. Together, our results suggest the CryJ-LAMP Vaccine has a potential as an effective therapeutic for JRC induced allergy by skewing Th1/Th2 responses. PMID:27239481

Prostaglandin E2 and IL-23 interconnects STAT3 and RoRγ pathways to initiate Th17 CD4+ T-cell development during rheumatoid arthritis.

PubMed

Samuels, Janaiya S; Holland, Lauren; López, María; Meyers, Keya; Cumbie, William G; McClain, Anna; Ignatowicz, Aleksandra; Nelson, Daryllynn; Shashidharamurthy, Rangaiah

2018-04-30

The chronic inflammation associated with rheumatoid arthritis (RA) leads to focal and systemic bone erosion of the joints resulting in a crippling disability. Recent reports indicate an increase in the incidence of RA in the coming years, placing a significant burden on healthcare resources. The incidence of RA is observed to be increasing with age and a significant proportion of those new cases will be aggressively erosive. The altered physiology, due to immune disturbances, contributes towards RA pathogenesis. The imbalance of inflammatory cytokines and non-cytokine immune modulators such as prostaglandin E2 (PGE2) and IL-23-induced pathogenic IL-17, plays a crucial role in persistent inflammation and bone degradation during RA. However, the molecular mechanism of IL-23, a key cytokine, and PGE2 in the development and perpetuation of IL-17 producing effector Th17 cells is poorly understood. This review focuses on research findings that provide insight into the contribution of PGE2 and IL-23 during the development of pathogenic Th17 cells. We also highlight the key transcriptional factors required for Th17 development and therapeutic strategies to disrupt the interaction between IL-23 and IL-17 to prevent the end-organ damage in RA.

Distinct regions of the Phytophthora essential effector Avh238 determine its function in cell death activation and plant immunity suppression.

PubMed

Yang, Bo; Wang, Qunqing; Jing, Maofeng; Guo, Baodian; Wu, Jiawei; Wang, Haonan; Wang, Yang; Lin, Long; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Wang, Yuanchao

2017-04-01

Phytophthora pathogens secrete effectors to manipulate host innate immunity, thus facilitating infection. Among the RXLR effectors highly induced during Phytophthora sojae infection, Avh238 not only contributes to pathogen virulence but also triggers plant cell death. However, the detailed molecular basis of Avh238 functions remains largely unknown. We mapped the regions responsible for Avh238 functions in pathogen virulence and plant cell death induction using a strategy that combines investigation of natural variation and large-scale mutagenesis assays. The correlation between cellular localization and Avh238 functions was also evaluated. We found that the 79 th residue (histidine or leucine) of Avh238 determined its cell death-inducing activity, and that the 53 amino acids in its C-terminal region are responsible for promoting Phytophthora infection. Transient expression of Avh238 in Nicotiana benthamiana revealed that nuclear localization is essential for triggering cell death, while Avh238-mediated suppression of INF1-triggered cell death requires cytoplasmic localization. Our results demonstrate that a representative example of an essential Phytophthora RXLR effector can evolve to escape recognition by the host by mutating one nucleotide site, and can also retain plant immunosuppressive activity to enhance pathogen virulence in planta. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Immunopathology of inflammatory bowel disease

PubMed Central

Wallace, Kori L; Zheng, Li-Bo; Kanazawa, Yoshitake; Shih, David Q

2014-01-01

Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important roles in the development of IBD either by causing inflammation directly or indirectly through an altered immune system. New technologies have allowed researchers to be able to quantify the various components of the microbiome, which will allow for future developments in the etiology of IBD. Various components of the mucosal immune system are implicated in the pathogenesis of IBD and include intestinal epithelial cells, innate lymphoid cells, cells of the innate (macrophages/monocytes, neutrophils, and dendritic cells) and adaptive (T-cells and B-cells) immune system, and their secreted mediators (cytokines and chemokines). Either a mucosal susceptibility or defect in sampling of gut luminal antigen, possibly through the process of autophagy, leads to activation of innate immune response that may be mediated by enhanced toll-like receptor activity. The antigen presenting cells then mediate the differentiation of naïve T-cells into effector T helper (Th) cells, including Th1, Th2, and Th17, which alter gut homeostasis and lead to IBD. In this review, the effects of these components in the immunopathogenesis of IBD will be discussed. PMID:24415853

Immunopathology of inflammatory bowel disease.

PubMed

Wallace, Kori L; Zheng, Li-Bo; Kanazawa, Yoshitake; Shih, David Q

2014-01-07

Inflammatory bowel disease (IBD) results from a complex series of interactions between susceptibility genes, the environment, and the immune system. The host microbiome, as well as viruses and fungi, play important roles in the development of IBD either by causing inflammation directly or indirectly through an altered immune system. New technologies have allowed researchers to be able to quantify the various components of the microbiome, which will allow for future developments in the etiology of IBD. Various components of the mucosal immune system are implicated in the pathogenesis of IBD and include intestinal epithelial cells, innate lymphoid cells, cells of the innate (macrophages/monocytes, neutrophils, and dendritic cells) and adaptive (T-cells and B-cells) immune system, and their secreted mediators (cytokines and chemokines). Either a mucosal susceptibility or defect in sampling of gut luminal antigen, possibly through the process of autophagy, leads to activation of innate immune response that may be mediated by enhanced toll-like receptor activity. The antigen presenting cells then mediate the differentiation of naïve T-cells into effector T helper (Th) cells, including Th1, Th2, and Th17, which alter gut homeostasis and lead to IBD. In this review, the effects of these components in the immunopathogenesis of IBD will be discussed.

Effector and regulatory dendritic cells display distinct patterns of miRNA expression

PubMed Central

Luce, Sonia; Moussu, Hélène; Morizur, Lise; Gueguen, Claire; Neukirch, Catherine; Chollet‐Martin, Sylvie; Mascarell, Laurent; Aubier, Michel; Baron‐Bodo, Véronique; Moingeon, Philippe

2017-01-01

Abstract Introduction MicroRNAs (miRNAs) contribute to the regulation of dendritic cell (DC) polarization, thereby influencing the balance of adaptive immune responses. Herein, we studied the expression of miRNAs in polarized DCs and analyzed whether expression of these miRNAs could be associated with allergic rhinitis and allergen immunotherapy (AIT) outcome. Method Using specific culture conditions, we differentiated immature human monocyte‐derived DCs into DC1, DC2, and DCreg subsets (supporting the differentiation of TH1, TH2 or regulatory T cells, respectively). Profiling of miRNA expression was performed in these DC subpopulations using microarrays. Levels of miRNAs specific for polarized DCs were then evaluated in a cohort of 58 patients with allergic rhinitis and 25 non‐allergic controls, as well as in samples from 30 subjects treated with sublingual grass pollen tablets or placebo for four months. Results We successfully identified 16 miRNAs differentially regulated between immature DCs, DC1, DC2, and DCreg cells. In allergic rhinoconjunctivitis patients, the expression of two of those miRNAs (miR‐132 and miR‐155), was down‐regulated compared to non‐allergic individuals. However, the levels of these miRNAs were not significantly modified following four months of grass pollen immunotherapy. Conclusions Studying polarized DCs and clinical samples from subjects with or without allergic rhinoconjunctivitis, we demonstrated that the expression of two miRNAs linked to effector DCs (i.e., DC1 and/or DC2 cells), was reduced in the blood of patients with allergic rhinoconjunctivitis. Nevertheless, these miRNAs did not represent relevant biomarkers to predict or follow‐up AIT efficacy. PMID:28497578

T Cell Intrinsic Function of the Noncanonical NF-κB Pathway in the Regulation of GM-CSF Expression and EAE Pathogenesis

PubMed Central

Yu, Jiayi; Zhou, Xiaofei; Nakaya, Mako; Jin, Wei; Cheng, Xuhong; Sun, Shao-Cong

2014-01-01

The Noncanonical NF-κB pathway induces processing of the NF-κB2 precursor protein p100 and, thereby, mediates activation of p52-containing NF-κB complexes. This pathway is crucial for B-cell maturation and humoral immunity, but its role in regulating T-cell function is less clear. Using mutant mice that express a non-processible p100, NF-κB2lym1, we show that the noncanonical NF-κB pathway has a T cell-intrinsic role in regulating the pathogenesis of a T cell-mediated autoimmunity, experimental autoimmune encephalomyelitis (EAE). Although the lym1 mutation does not interfere with naïve T-cell activation, it renders the Th17 cells defective in the production of inflammatory effector molecules, particularly the cytokine GM-CSF. We provide evidence that p52 binds to the promoter of the GM-CSF-encoding gene (Csf2) and cooperates with c-Rel in the transactivation of this target gene. Introduction of exogenous p52 or GM-CSF to the NF-κB2lym1 mutant T cells partially restores their ability to induce EAE. These results suggest that the noncanonical NF-κB pathway mediates induction of EAE by regulating the effector function of inflammatory T cells. PMID:24899500

Myocardial Gene Expression of T-bet, GATA-3, Ror-γt, FoxP3, and Hallmark Cytokines in Chronic Chagas Disease Cardiomyopathy: An Essentially Unopposed TH1-Type Response

PubMed Central

Nogueira, Luciana Gabriel; Santos, Ronaldo Honorato Barros; Fiorelli, Alfredo Inácio; Mairena, Eliane Conti; Benvenuti, Luiz Alberto; Bocchi, Edimar Alcides; Stolf, Noedir Antonio; Kalil, Jorge; Cunha-Neto, Edecio

2014-01-01

Background. Chronic Chagas disease cardiomyopathy (CCC), a late consequence of Trypanosoma cruzi infection, is an inflammatory cardiomyopathy with prognosis worse than those of noninflammatory etiology (NIC). Although the T cell-rich myocarditis is known to play a pathogenetic role, the relative contribution of each of the functional T cell subsets has never been thoroughly investigated. We therefore assessed gene expression of cytokines and transcription factors involved in differentiation and effector function of each functional T cell subset (TH1/TH2/TH17/Treg) in CCC, NIC, and heart donor myocardial samples. Methods and Results. Quantitative PCR showed markedly upregulated expression of IFN-γ and transcription factor T-bet, and minor increases of GATA-3; FoxP3 and CTLA-4; IL-17 and IL-18 in CCC as compared with NIC samples. Conversely, cytokines expressed by TH2 cells (IL-4, IL-5, and IL-13) or associated with Treg (TGF-β and IL-10) were not upregulated in CCC myocardium. Expression of TH1-related genes such as T-bet, IFN-γ, and IL-18 correlated with ventricular dilation, FoxP3, and CTLA-4. Conclusions. Results are consistent with a strong local TH1-mediated response in most samples, possibly associated with pathological myocardial remodeling, and a proportionally smaller FoxP3+CTLA4+ Treg cell population, which is unable to completely curb IFN-γ production in CCC myocardium, therefore fueling inflammation. PMID:25152568

Functional heterogeneity of human effector CD8+ T cells.

PubMed

Takata, Hiroshi; Naruto, Takuya; Takiguchi, Masafumi

2012-02-09

Effector CD8(+) T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-γ and TNF-α. We investigated the difference between CXCR1(+) and CXCR1(-) subsets of human effector CD27(-)CD28(-)CD8(+) T cells. The subsets expressed cytolytic molecules similarly and exerted substantial cytolytic activity, whereas only the CXCR1(-) subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1(+) subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1(-) subset and that of pro-apoptotic death-associated protein kinase 1 (DAPK1) in the CXCR1(+) subset. The IL-2 producers were more frequently found in the IL-7R(+) subset of the CXCR1(-) effector CD8(+) T cells than in the IL-7R(-) subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1(-) subset. The present study has highlighted a novel subset of effector CD8(+) T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8(+) T cells.

MicroRNA-155 Modulates Acute Graft-versus-Host Disease by Impacting T Cell Expansion, Migration, and Effector Function.

PubMed

Zitzer, Nina C; Snyder, Katiri; Meng, Xiamoei; Taylor, Patricia A; Efebera, Yvonne A; Devine, Steven M; Blazar, Bruce R; Garzon, Ramiro; Ranganathan, Parvathi

2018-06-15

MicroRNA-155 (miR-155) is a small noncoding RNA critical for the regulation of inflammation as well as innate and adaptive immune responses. MiR-155 has been shown to be dysregulated in both donor and recipient immune cells during acute graft-versus-host disease (aGVHD). We previously reported that miR-155 is upregulated in donor T cells of mice and humans with aGVHD and that mice receiving miR-155-deficient (miR155 -/- ) splenocytes had markedly reduced aGVHD. However, molecular mechanisms by which miR-155 modulates T cell function in aGVHD have not been fully investigated. We identify that miR-155 expression in both donor CD8 + T cells and conventional CD4 + CD25 - T cells is pivotal for aGVHD pathogenesis. Using murine aGVHD transplant experiments, we show that miR-155 strongly impacts alloreactive T cell expansion through multiple distinct mechanisms, modulating proliferation in CD8 + donor T cells and promoting exhaustion in donor CD4 + T cells in both the spleen and colon. Additionally, miR-155 drives a proinflammatory Th1 phenotype in donor T cells in these two sites, and miR-155 -/- donor T cells are polarized toward an IL-4-producing Th2 phenotype. We further demonstrate that miR-155 expression in donor T cells regulates CCR5 and CXCR4 chemokine-dependent migration. Notably, we show that miR-155 expression is crucial for donor T cell infiltration into multiple target organs. These findings provide further understanding of the role of miR-155 in modulating aGVHD through T cell expansion, effector cytokine production, and migration. Copyright © 2018 by The American Association of Immunologists, Inc.

Immunology mini-review: the basics of T(H)17 and interleukin-6 in transplantation.

PubMed

Nakagiri, T; Inoue, M; Minami, M; Shintani, Y; Okumura, M

2012-05-01

The outcomes of organ transplantation are determined by graft rejection, the mechanisms of which are some of the most important areas of study in the transplantation field. The main cause of rejection is the immunologic response of the recipient toward the transplanted organ. The immunologic responses are regulated by T-cell subsets, especially helper T-cells, which have been characterized as T(H)1 or T(H)2 cells according to their profiles of cytokines production. A unique subset of recently identified lymphocytes, the regulatory T cells (T(reg)s), seem to play a role in tolerance. The recently identified T(H)17 cells are a subset of effector-helper lymphocytes that specifically secrete interleukin (IL) 17. Interestingly, T(H)17 and T(reg) both develop from naïve T cells on stimulation by transforming growth factor β. The difference is only the existence of IL-6, a proinflammatory cytokine. T(H)17 clears pathogens that are not adequately handled by T(H)1 and T(H)2 elements, as well as contributing to autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory diseases. Autoimmune diseases are caused by reactions to self-antigens. T(H)17 (or IL-17) and IL-6 are also thought to be involved in rejection after organ transplantation. We examined the contributions of T(H)17 and IL-6 in bronchiolitis obliterans (BO), the histologic finding in chronic rejection of lung transplantations. Earlier studies have reported that T(H)17 and IL-6 contribute not only to chronic rejection of lung transplantations, but also to the rejection of other solid organs, e.g., heart, liver, and kidney. In addition, prospective avenues of research on T(H)17 and IL-6 in transplantation have emerged from the perspectives of recent studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Multicolor flow-cytometric analysis of milk allergen-specific T-helper type 2 cells revealed coexpression of interleukin-4 with Foxp3.

PubMed

Yamawaki, Kazuo; Inuo, Chisato; Nomura, Takayasu; Tanaka, Kenichi; Nakajima, Yoichi; Kondo, Yasuto; Yoshikawa, Tetsushi; Urisu, Atsuo; Tsuge, Ikuya

2015-12-01

Allergen-specific T-helper type 2 (TH2) cells play an important role in the development of allergic inflammation; however, investigations of the properties of allergen-specific T cells have been challenging in humans. Despite clear evidence that forkhead box p3 (Foxp3) is expressed in conventional effector T cells, its function has remained unknown. To characterize allergen-specific TH2 cells in milk allergy, with particular focus on the expression of Foxp3. Twenty-one children with milk allergy and 11 children without milk allergy were studied. Peripheral blood mononuclear cells from subjects were stimulated with milk allergen for 6 hours and analyzed using multicolor flow cytometry to identify CD154(+) allergen-specific T-helper cells. Simultaneously, the expression of intracellular cytokines and Foxp3 was analyzed. The milk allergy group had significantly larger numbers of milk allergen-specific interleukin (IL)-4- and IL-5-producing CD4(+) T cells than the control group. Subjects in the milk allergy group had significantly more CD154(+)CD4(+) IL-10-producing cells and CD154(+)Foxp3(+)CD4(+) cells than those in the control group. In addition, the number of milk allergen-specific CD154(+)Foxp3(+)CD4(+) cells strongly correlated with that of CD154(+)IL4(+)CD4(+) cells. Bcl-2 expression in CD154(+)IL-4(+)Foxp3(+) T-helper cells was significantly lower compared with that in total CD4 cells. Increased numbers of IL-4-producing allergen-specific T-helper cells were found in patients with milk allergy. In addition, Foxp3 was coexpressed with IL-4 in allergen-specific TH2 cells from patients. This coexpression was associated with lower Bcl-2 levels and could contribute to the phenotype and function of TH2 cells. Copyright © 2015 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Re-defining the Unique Roles for Eosinophils in Allergic Respiratory Inflammation

PubMed Central

Jacobsen, Elizabeth A.; Lee, Nancy A.; Lee, James J.

2014-01-01

Summary The role of eosinophils in the progression and resolution of allergic respiratory inflammation is poorly defined despite the commonality of their presence and in some cases their use as a biomarker for disease severity and/or symptom control. However, this ambiguity belies the wealth of insights that have recently been gained through the use of eosinophil-deficient/attenuated strains of mice that have demonstrated novel immunoregulatory and remodeling/repair functions for these cells in the lung following allergen provocation. Specifically, studies of eosinophil-deficient mice suggest that eosinophils contribute to events occurring in the lungs following allergen provocation at several key moments: (i) The initiating phase of events leading to Th2-polarized pulmonary inflammation, (ii) The suppression Th1/Th17 pathways in lung draining lymph nodes, (iii) The recruitment of effector Th2 T cells to the lung, and finally (iv) Mechanisms of inflammatory resolution that re-establish pulmonary homeostasis. These suggested functions have recently been confirmed and expanded upon using allergen provocation of an inducible eosinophil-deficient strain of mice (iPHIL) that demonstrated an eosinophil-dependent mechanism(s) leading to Th2 dominated immune responses in the presence of eosinophils in contrast to neutrophilic as well as mixed Th1/Th17/Th2 variant phenotypes in the absence of eosinophils. These findings highlighted that eosinophils are not exclusively downstream mediators controlled by T cells, dendritic cells (DC), and/or innate lymphocytic cells (ILC2). Instead, eosinophils appear to be more aptly described as significant contributors in complex interrelated pathways that lead to pulmonary inflammation and subsequently promote resolution and the re-establishment of homeostatic baseline. In this review we summarize and put into the context the evolving hypotheses that are now expanding our understanding of the roles eosinophils likely have in the lung following allergen provocation. PMID:24961290

TSC1 regulates the balance between effector and regulatory T cells.

PubMed

Park, Yoon; Jin, Hyung-Seung; Lopez, Justine; Elly, Chris; Kim, Gisen; Murai, Masako; Kronenberg, Mitchell; Liu, Yun-Cai

2013-12-01

Mammalian target of rapamycin (mTOR) plays a crucial role in the control of T cell fate determination; however, the precise regulatory mechanism of the mTOR pathway is not fully understood. We found that T cell-specific deletion of the gene encoding tuberous sclerosis 1 (TSC1), an upstream negative regulator of mTOR, resulted in augmented Th1 and Th17 differentiation and led to severe intestinal inflammation in a colitis model. Conditional Tsc1 deletion in Tregs impaired their suppressive activity and expression of the Treg marker Foxp3 and resulted in increased IL-17 production under inflammatory conditions. A fate-mapping study revealed that Tsc1-null Tregs that lost Foxp3 expression gained a stronger effector-like phenotype compared with Tsc1-/- Foxp3+ Tregs. Elevated IL-17 production in Tsc1-/- Treg cells was reversed by in vivo knockdown of the mTOR target S6K1. Moreover, IL-17 production was enhanced by Treg-specific double deletion of Tsc1 and Foxo3a. Collectively, these studies suggest that TSC1 acts as an important checkpoint for maintaining immune homeostasis by regulating cell fate determination.

The CD4+ T cell regulatory network mediates inflammatory responses during acute hyperinsulinemia: a simulation study.

PubMed

Martinez-Sanchez, Mariana E; Hiriart, Marcia; Alvarez-Buylla, Elena R

2017-06-26

Obesity is frequently linked to insulin resistance, high insulin levels, chronic inflammation, and alterations in the behaviour of CD4+ T cells. Despite the biomedical importance of this condition, the system-level mechanisms that alter CD4+ T cell differentiation and plasticity are not well understood. We model how hyperinsulinemia alters the dynamics of the CD4+ T regulatory network, and this, in turn, modulates cell differentiation and plasticity. Different polarizing microenvironments are simulated under basal and high levels of insulin to assess impacts on cell-fate attainment and robustness in response to transient perturbations. In the presence of high levels of insulin Th1 and Th17 become more stable to transient perturbations, and their basin sizes are augmented, Tr1 cells become less stable or disappear, while TGFβ producing cells remain unaltered. Hence, the model provides a dynamic system-level framework and explanation to further understand the documented and apparently paradoxical role of TGFβ in both inflammation and regulation of immune responses, as well as the emergence of the adipose Treg phenotype. Furthermore, our simulations provide new predictions on the impact of the microenvironment in the coexistence of the different cell types, suggesting that in pro-Th1, pro-Th2 and pro-Th17 environments effector and regulatory cells can coexist, but that high levels of insulin severely diminish regulatory cells, especially in a pro-Th17 environment. This work provides a first step towards a system-level formal and dynamic framework to integrate further experimental data in the study of complex inflammatory diseases.

The Role of Th17 in Neuroimmune Disorders: Target for CAM Therapy. Part I.

PubMed

Vojdani, Aristo; Lambert, Jama

2011-01-01

CD4(+) effector cells, based on cytokine production, nuclear receptors and signaling pathways, have been categorized into four subsets. T-helper-1 cells produce IFN-γ, TNF-β, lymphotoxin and IL-10; T-helper-2 cells produce IL-4, IL-5, IL-10, IL-13, IL-21 and IL-31; T-helper-3, or regulatory T-cells, produce IL-10, TGF-β and IL-35; and the recently discovered T-helper-17 cell produces IL-17, IL-17A, IL-17F, IL-21, IL-26 and CCL20. By producing IL-17 and other signaling molecules, Th17 contributes to the pathogenesis of multiple autoimmune diseases including allergic inflammation, rheumatoid arthritis, autoimmune gastritis, inflammatory bowel disease, psoriasis and multiple sclerosis. In this article, we review the differential regulation of inflammation in different tissues with a major emphasis on enhancement of neuroinflammation by local production of IL-17 in the brain. By understanding the role of pathogenic factors in the induction of autoimmune diseases by Th17 cells, CAM practitioners will be able to design CAM therapies targeting Th17 and associated cytokine activities and signaling pathways to repair the intestinal and blood-brain barriers for their patients with autoimmunities, in particular, those with neuroinflammation and neurodegeneration.

STAT3 signaling in CD4+ T cells is critical for the pathogenesis of chronic sclerodermatous graft-versus-host disease in a murine model.

PubMed

Radojcic, Vedran; Pletneva, Maria A; Yen, Hung-Rong; Ivcevic, Sanja; Panoskaltsis-Mortari, Angela; Gilliam, Anita C; Drake, Charles G; Blazar, Bruce R; Luznik, Leo

2010-01-15

Donor CD4+ T cells are thought to be essential for inducing delayed host tissue injury in chronic graft-versus-host disease (GVHD). However, the relative contributions of distinct effector CD4+ T cell subpopulations and the molecular pathways influencing their generation are not known. We investigated the role of the STAT3 pathway in a murine model of chronic sclerodermatous GVHD. This pathway integrates multiple signaling events during the differentiation of naive CD4+ T cells and impacts their homeostasis. We report that chimeras receiving an allograft containing STAT3-ablated donor CD4+ T cells do not develop classic clinical and pathological manifestations of alloimmune tissue injury. Analysis of chimeras showed that abrogation of STAT3 signaling reduced the in vivo expansion of donor-derived CD4+ T cells and their accumulation in GVHD target tissues without abolishing antihost alloreactivity. STAT3 ablation did not significantly affect Th1 differentiation while enhancing CD4+CD25+Foxp3+ T cell reconstitution through thymus-dependent and -independent pathways. Transient depletion of CD25+ T cells in chimeras receiving STAT3-deficient T cells resulted in delayed development of alloimmune gut and liver injury. This delayed de novo GVHD was associated with the emergence of donor hematopoietic stem cell-derived Th1 and Th17 cells. These results suggest that STAT3 signaling in graft CD4+ T cells links the alloimmune tissue injury of donor graft T cells and the emergence of donor hematopoietic stem cell-derived pathogenic effector cells and that both populations contribute, albeit in different ways, to the genesis of chronic GVHD after allogenic bone marrow transplantation in a murine model.

Naive helper T cells from BCG-vaccinated volunteers produce IFN-gamma and IL-5 to mycobacterial antigen-pulsed dendritic cells.

PubMed

Kowalewicz-Kulbat, Magdalena; Kaźmierczak, Dominik; Donevski, Stefan; Biet, Franck; Pestel, Joël; Rudnicka, Wiesława

2008-01-01

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is a live vaccine that has been used in routine vaccination against tuberculosis for nearly 80 years. However, its efficacy is controversial. The failure of BCG vaccination may be at least partially explained by the induction of poor or inappropriate host responses. Dendritic cells (DCs) are likely to play a key role in the induction of immune response to mycobacteria by polarizing the reactivity of T lymphocytes toward a Th1 profile, contributing to the generation of protective cellular immunity against mycobacteria. In this study we aimed to investigate the production of Th1 and Th2 cytokines by naive CD4+ T cells to mycobacterial antigen-pulsed DCs in the group of young, healthy BCG vaccinated volunteers. The response of naive helper T cells was compared with the response of total blood lymphocytes. Our present results clearly showed that circulating naive CD45RA+CD4+ lymphocytes from BCG-vaccinated subjects can become effector helper cells producing IFN-gamma and IL-5 under the stimulation by autologous dendritic cells presenting mycobacterial protein antigen-PPD or infected with live M. bovis BCG bacilli.

Strategies of immunization against mucosal infections.

PubMed

Russell, M W; Martin, M H; Wu, H Y; Hollingshead, S K; Moldoveanu, Z; Mestecky, J

2000-12-08

The presence of secretory (S-) IgA in middle-ear fluid and localization of IgA-secreting cells in its mucosae suggest that the middle ear is an effector site of the mucosal immune system. Several strategies have been devised to induce potent, long-lasting, and recallable mucosal S-IgA antibodies, as well as circulating IgG antibodies and Th1- or Th2-type help, according to the most appropriate responses for a particular infection. Application of immunogens to inductive sites in the upper respiratory tract may be most effective for generating responses in the middle ear and nasopharynx for protection against the organisms responsible for otitis media.

Differential Activation of Airway Eosinophils Induces IL-13 Mediated Allergic Th2 Pulmonary Responses in Mice

PubMed Central

Jacobsen, EA; Doyle, AD; Colbert, DC; Zellner, KR; Protheroe, CA; LeSuer, WE; Lee, NA.; Lee, JJ

2015-01-01

Background Eosinophils are hallmark cells of allergic Th2 respiratory inflammation. However, the relative importance of eosinophil activation and the induction of effector functions such as the expression of IL-13 to allergic Th2 pulmonary disease remain to be defined. Methods Wild type or cytokine deficient (IL-13−/− or IL-4−/−) eosinophils treated with cytokines (GM-CSF, IL-4, IL-33) were adoptively transferred into eosinophil-deficient recipient mice subjected to allergen provocation using established models of respiratory inflammation. Allergen-induced pulmonary changes were assessed. Results In contrast to the transfer of untreated blood eosinophils to the lungs of recipient eosinophildeficient mice, which induced no immune/inflammatory changes either in the lung or lung draining lymph nodes (LDLNs), pretreatment of blood eosinophils with GM-CSF prior to transfer elicited trafficking of these eosinophils to LDLNs. In turn, these LDLN eosinophils elicited the accumulation of dendritic cells and CD4+ T cells to these same LDLNs without inducing pulmonary inflammation. However, exposure of eosinophils to GM-CSF, IL-4 and IL-33 prior to transfer induced not only immune events in the LDLN, but also allergen-mediated increases in airway Th2 cytokine/chemokine levels, the subsequent accumulation of CD4+ T cells as well as alternatively activated (M2) macrophages, and the induction of pulmonary histopathologies. Significantly, this allergic respiratory inflammation was dependent on eosinophil-derived IL-13 whereas IL-4 expression by eosinophils had no significant role. Conclusion The data demonstrate the differential activation of eosinophils as a function of cytokine exposure and suggest that eosinophil-specific IL-13 expression by activated cells is a necessary component of the subsequent allergic Th2 pulmonary pathologies. PMID:26009788

Differential activation of airway eosinophils induces IL-13-mediated allergic Th2 pulmonary responses in mice.

PubMed

Jacobsen, E A; Doyle, A D; Colbert, D C; Zellner, K R; Protheroe, C A; LeSuer, W E; Lee, N A; Lee, J J

2015-09-01

Eosinophils are hallmark cells of allergic Th2 respiratory inflammation. However, the relative importance of eosinophil activation and the induction of effector functions such as the expression of IL-13 to allergic Th2 pulmonary disease remain to be defined. Wild-type or cytokine-deficient (IL-13(-/-) or IL-4(-/-) ) eosinophils treated with cytokines (GM-CSF, IL-4, IL-33) were adoptively transferred into eosinophil-deficient recipient mice subjected to allergen provocation using established models of respiratory inflammation. Allergen-induced pulmonary changes were assessed. In contrast to the transfer of untreated blood eosinophils to the lungs of recipient eosinophil deficient mice, which induced no immune/inflammatory changes either in the lung or in the lung draining lymph nodes (LDLN), pretreatment of blood eosinophils with GM-CSF prior to transfer elicited trafficking of these eosinophils to LDLN. In turn, these LDLN eosinophils elicited the accumulation of dendritic cells and CD4(+) T cells to these same LDLNs without inducing pulmonary inflammation. However, exposure of eosinophils to GM-CSF, IL-4, and IL-33 prior to transfer induced not only immune events in the LDLN, but also allergen-mediated increases in airway Th2 cytokine/chemokine levels, the subsequent accumulation of CD4(+) T cells as well as alternatively activated (M2) macrophages, and the induction of pulmonary histopathologies. Significantly, this allergic respiratory inflammation was dependent on eosinophil-derived IL-13, whereas IL-4 expression by eosinophils had no significant role. The data demonstrate the differential activation of eosinophils as a function of cytokine exposure and suggest that eosinophil-specific IL-13 expression by activated cells is a necessary component of the subsequent allergic Th2 pulmonary pathologies. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Transcription factor interplay in T helper cell differentiation.

PubMed

Evans, Catherine M; Jenner, Richard G

2013-11-01

The differentiation of CD4 helper T cells into specialized effector lineages has provided a powerful model for understanding immune cell differentiation. Distinct lineages have been defined by differential expression of signature cytokines and the lineage-specifying transcription factors necessary and sufficient for their production. The traditional paradigm of differentiation towards Th1 and Th2 subtypes driven by T-bet and GATA3, respectively, has been extended to incorporate additional T cell lineages and transcriptional regulators. Technological advances have expanded our view of these lineage-specifying transcription factors to the whole genome and revealed unexpected interplay between them. From these data, it is becoming clear that lineage specification is more complex and plastic than previous models might have suggested. Here, we present an overview of the different forms of transcription factor interplay that have been identified and how T cell phenotypes arise as a product of this interplay within complex regulatory networks. We also suggest experimental strategies that will provide further insight into the mechanisms that underlie T cell lineage specification and plasticity.

Cellular and humoral immune responses during tuberculosis infection: useful knowledge in the era of biological agents.

PubMed

Matucci, Andrea; Maggi, Enrico; Vultaggio, Alessandra

2014-05-01

In this review, recent insights into innate and adaptive cellular and humoral immune response to Mycobacterium tuberculosis (Mtb) are discussed and the role of specific cytokines such as tumor necrosis factor-α (TNF-α) is highlighted. According to recent findings, the immune system plays a key role in avoiding mycobacteria dissemination. The importance of different cell types (macrophages, dendritic cells, interferon-γ-producing T cells) as well as the production of proinflammatory cytokines such as interleukin 6 (IL-6), IL-12, and IL-23/IL-17 have been demonstrated. Alveolar macrophages are considered the first cells infected by Mtb during respiratory infection. Mtb proliferates within alveolar macrophages and dendritic cells and induces the release of cytokines such as TNF-α, IL-1, IL-6, and IL-12. Toll-like receptors-stimulated dendritic cells link innate and adaptive immunity by promoting polarization of effector T cells. The efficient induction of Th1 immunity is decisive in defense against Mtb. In fact, host effector immune response against Mtb is related to the presence of a Th1 response. The definition of the cellular and molecular mechanisms involved in the immune response to Mtb can be helpful in developing new preventive strategies to avoid infection relapse, particularly in patients treated with biological agents.

Human Pancreatic Cancer Cells Induce a MyD88-Dependent Stromal Response To Promote a Tumor-Tolerant Immune Microenvironment

PubMed Central

Delitto, Daniel; Delitto, Andrea E.; DiVita, Bayli B.; Pham, Kien; Han, Song; Hartlage, Emily R.; Newby, Brittney N.; Gerber, Michael H.; Behrns, Kevin E.; Moldawer, Lyle L.; Thomas, Ryan M.; George, Thomas J.; Brusko, Todd M.; Mathews, Clayton E.; Liu, Chen; Trevino, Jose G.; Hughes, Steven J.; Wallet, Shannon M.

2016-01-01

Cancer cells exert mastery over the local tumor-associated stroma (TAS) to configure protective immunity within the tumor microenvironment. The immunomodulatory character of pancreatic lysates of patients with cancer differs from those with pancreatitis. In this study, we evaluated the crosstalk between pancreatic cancer (PC) and its TAS in primary human cell culture models. Upon exposure of TAS to PC cell-conditioned media, we documented robust secretion of IL-6 and IL-8. This TAS response was MyD88-dependent and sufficient to directly suppress both CD4+ and CD8+ T cell proliferation, inducing Th17 polarization at the expense of Th1. We found that patients possessed a similar shift in circulating effector memory Th17:Th1 ratios compared to healthy controls. The TAS response also directly suppressed CD8+ T cell-mediated cytotoxicity. Overall, our results demonstrate how TAS contributes to the production of an immunosuppressive tumor microenvironment in pancreatic cancer. PMID:27864347

Decreased release of histamine and sulfidoleukotrienes by human peripheral blood leukocytes after wasp venom immunotherapy is partially due to induction of IL-10 and IFN-gamma production of T cells.

PubMed

Pierkes, M; Bellinghausen, I; Hultsch, T; Metz, G; Knop, J; Saloga, J

1999-02-01

Recent studies provide evidence that venom immunotherapy (VIT) alters the pattern of cytokine production by inducing an allergen-specific T-cell shift in cytokine expression from TH2 (IL-4, IL-5) to TH1 (IFN-gamma) cytokines and also inducing the production of IL-10. This study was carried out to analyze whether these changes in cytokine production of T cells already observed 1 week after the initiation of VIT in subjects with wasp venom allergy also influence the reactivity of effector cells, such as mast cells and basophils. All subjects included in this study had a history of severe systemic allergic reactions to wasp stings and positive skin test responses with venom and venom-specific IgE in the sera. Peripheral blood leukocytes were isolated before and after the initiation of VIT (rush therapy reaching a maintenance dose of 100 microg venom injected subcutaneously within 1 week) and preincubated with or without addition of IL-10, IFN-gamma, IL-10 + IFN-gamma, anti-IL-10, or anti-IFN-gamma. After stimulation with wasp venom, histamine and sulfidoleukotriene release were assessed by ELISA and compared with spontaneous release and total histamine content. After the induction of VIT, venom-induced absolute and relative histamine and sulfidoleukotriene release were reduced. This was at least partially due to the induction of IFN-gamma and IL-10 production, because (1) neutralization of IL-10 and IFN-gamma by mAbs partially restored the release after the initiation of VIT and (2) the addition of exogenous IFN-gamma and IL-10 caused a statistically significant diminution of the venom-induced histamine and sulfidoleukotriene release before VIT. Depletion of CD2(+) T cells also restored the releasability after VIT. These data indicate that T cells (producing IL-10 and IFN-gamma after VIT) play a key role for the inhibition of histamine and sulfidoleukotriene release of effector cells.

Chronically Elevated Levels of Short-Chain Fatty Acids Induce T Cell-Mediated Ureteritis and Hydronephrosis.

PubMed

Park, Jeongho; Goergen, Craig J; HogenEsch, Harm; Kim, Chang H

2016-03-01

Short-chain fatty acids (SCFAs) are major products of gut microbial fermentation and profoundly affect host health and disease. SCFAs generate IL-10(+) regulatory T cells, which may promote immune tolerance. However, SCFAs can also induce Th1 and Th17 cells upon immunological challenges and, therefore, also have the potential to induce inflammatory responses. Because of the seemingly paradoxical SCFA activities in regulating T cells, we investigated, in depth, the impact of elevated SCFA levels on T cells and tissue inflammation in mice. Orally administered SCFAs induced effector (Th1 and Th17) and regulatory T cells in ureter and kidney tissues, and they induced T cell-mediated ureteritis, leading to kidney hydronephrosis (hereafter called acetate-induced renal disease, or C2RD). Kidney hydronephrosis in C2RD was caused by ureteral obstruction, which was, in turn, induced by SCFA-induced inflammation in the ureteropelvic junction and proximal ureter. Oral administration of all major SCFAs, such as acetate, propionate, and butyrate, induced the disease. We found that C2RD development is dependent on mammalian target of rapamycin activation, T cell-derived inflammatory cytokines such as IFN-γ and IL-17, and gut microbiota. Young or male animals were more susceptible than old or female animals, respectively. However, SCFA receptor (GPR41 or GPR43) deficiency did not affect C2RD development. Thus, SCFAs, when systemically administered at levels higher than physiological levels, cause dysregulated T cell responses and tissue inflammation in the renal system. The results provide insights into the immunological and pathological effects of chronically elevated SCFAs. Copyright © 2016 by The American Association of Immunologists, Inc.

Targeting Stat3 in the myeloid compartment drastically improves the in vivo antitumor functions of adoptively transferred T cells

PubMed Central

Herrmann, Andreas; Kortylewski, Marcin; Kujawski, Maciej; Zhang, Chunyan; Reckamp, Karen; Armstrong, Brian; Wang, Lin; Kowolik, Claudia; Deng, Jiehui; Robert, Figlin; Yu, Hua

2010-01-01

Improving effector T cell functions is highly desirable for preventive or therapeutic interventions of diverse diseases. Stat3 in the myeloid compartment constrains Th-1 type immunity, dampening natural and induced antitumor immune responses. We have recently developed an in vivo siRNA delivery platform by conjugating a TLR9 agonist with siRNA that efficiently targets myeloid and B cells. Here we show that either ablating the Stat3 alleles in the myeloid compartment and B cells combined with CpG triggering or administrating the CpG-Stat3siRNA conjugates drastically augments effector functions of adoptively transferred CD8+ T cells. Specifically, we demonstrate that both approaches are capable of increasing dendritic cell and CD8+ T cell engagement in tumor draining lymph nodes. Furthermore, both approaches can significantly activate the transferred CD8+ T cells in vivo, upregulating effector molecules such as perforin, granzyme B and IFN-γ. Intravital multiphoton microscopy reveals that Stat3 silencing combined with CpG triggering greatly increases killing activity and tumor infiltration of transferred T cells. These results suggest the use of CpG-Stat3siRNA, and possibly other Stat3 inhibitors, as a potent adjuvant to improve T cell therapies. PMID:20841481

Diverse functions of miR-17-92 cluster microRNAs in T helper cells.

PubMed

Baumjohann, Dirk

2018-06-01

T helper (Th) cells are critically involved in adaptive immune responses against various pathogens. In contrast, dysregulated T helper cell responses are associated with a variety of diseases, including autoimmunity, allergies, and cancer. Differentiation of naïve CD4 + T cells into effector T helper cell subsets, including Th1, Th2, Th17, Treg, and T follicular helper (Tfh), requires precise dosing of signaling molecules and transcription factors. MicroRNAs (miRNAs), which are small endogenously expressed RNAs that regulate gene expression, play important roles in these processes. The miR-17-92 cluster, a miRNA polycistron also known as oncomiR-1, has emerged as a central integrator of gene expression events that govern T helper cell differentiation pathways. The complexity of miR-17-92-mediated gene regulation lies in the nature of this miRNA cluster, which consists of six different miRNAs. Individual miR-17-92 miRNAs, albeit initially transcribed as one transcript, can have cooperative or opposing effects on biological processes. Therefore, a better understanding of the molecular regulation of miR-17-92 and its downstream networks will provide important insights into T helper cell differentiation and diversity that may be harnessed for the design of advanced T cell-targeting therapies. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular cloning of a Poria cocos protein that activates Th1 immune response and allays Th2 cytokine and IgE production in a murine atopic dermatitis model.

PubMed

Lu, Ya-Ting; Kuan, Yen-Chou; Chang, Hui-Hsin; Sheu, Fuu

2014-04-02

Edible fungus Poria cocos (Schw.) Wolf is a cooking material that has myriad health benefits. However, its active constituents have not been well-defined. We previously purified an immunomodulatory protein, PCP, from P. cocos and described its biochemical features and its ability to activate primary macrophage via TLR4. In this study, we cloned the gene of PCP and demonstrated its ability to activate Th1 response in cell cultures and in mice. The complete cDNA sequence of PCP consisted of 807 bp, which included a 579 bp coding sequence that encoded 194 amino acids. With the addition of co-stimulatory CD3/CD28 signals, PCP significantly increased the surface expression of CD44 and CD69 on effector T cells. PCP could also up-regulate T-bet and STAT4 expressions and IFN-γ and IL-2 secretions. Oral administration of PCP suppressed the production of both total and OVA-specific IgG1 in serum and enhanced the amounts of serum and OVA-specific IgG2a and Th1-related cytokine production in BALB/c splenocytes. In addition, oral administration of PCP significantly reduced IL-4 and IgE expressions in a murine model of atopic dermatitis. In conclusion, these results provide evidence that PCP could regulate mammalian immune cells and reveal their pharmaceutical potential in developing therapeutic strategies against Th2-mediated immune disorders.

Role of Type 2 Innate Lymphoid Cells in Allergic Diseases.

PubMed

Cosmi, Lorenzo; Liotta, Francesco; Maggi, Laura; Annunziato, Francesco

2017-09-11

The adaptive immune response orchestrated by type 2 T helper (Th2) lymphocytes, strictly cooperates with the innate response of group 2 innate lymphoid cells (ILC2), in the protection from helminths infection, as well as in the pathogenesis of allergic disease. The aim of this review is to explore the pathogenic role of ILC2 in different type 2-mediated disorders. Recent studies have shown that epithelial cell-derived cytokines and their responding cells, ILC2, play a pathogenic role in bronchial asthma, chronic rhinosinusitis, and atopic dermatitis. The growing evidences of the contribution of ILC2 in the induction and maintenance of allergic inflammation in such disease suggest the possibility to target them in therapy. Biological therapies blocking ILC2 activation or neutralizing their effector cytokines are currently under evaluation to be used in patients with type 2-dominated diseases.

Curcumin up regulates T helper 1 cells in patients with colon cancer.

PubMed

Xu, Bin; Yu, Lin; Zhao, Li-Zhong

2017-01-01

The therapy for the advanced colon cancer (Cca) is unsatisfactory currently. To regulate the immune effector cell function has shown a positive effect on the treatment of advanced cancers. This study tests a hypothesis that administration with curcumin converts the Cca patient-derived regulatory T cells (Treg) to T helper (Th) 1 cells. In this study, a group of patients with advanced Cca was recruited into this study. The patients were treated with curcumin. The peripheral Tregs and Th1 cells were assessed by flow cytometry. The results showed that, after the curcumin therapy, the forkhead box protein (Foxp) 3 positive Treg frequency was markedly reduced, the frequency of Th1 cells was significantly increased in Cca patients. Treating with curcumin repressed the Foxp3 gene transcription in Tregs; the Tregs were then converted into Th1 cells. The results also revealed that Foxp3 bound T-bet to prevent IFN-γ expression in CD4 + T cells, which was abolished by treating with curcumin. In conclusion, the administration of curcumin can convert Tregs to Th1 cells via repressing Foxp3 expression and enhancing IFN-γ production.

Increased Levels of Pro-Inflammatory and Anti-Inflammatory Cellular Responses in Parkinson's Disease Patients: Search for a Disease Indicator.

PubMed

Yang, Likun; Guo, Changfeng; Zhu, Jie; Feng, Yi; Chen, Weiliang; Feng, Zhizhong; Wang, Dan; Sun, Shibai; Lin, Wei; Wang, Yuhai

2017-06-18

BACKGROUND Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder and it arises when most of the dopaminergic neurons of substantia nigra region die. Several mechanisms have been postulated as the causative event in PD pathology, and neuroinflammation is most crucial among them. MATERIAL AND METHODS We analyzed T-helper 17 (Th17) cells and myeloid-derived suppressor cells (MDSCs) from 80 PD patients to assess inflammatory processes and to find a cost-effective means to evaluate PD prognosis. RESULTS We found significantly increased numbers of Th17 cells and MDSCs count in peripheral circulation in PD patients compared with controls (p<0.001). A positive correlation was found between Th17 cells and MDSCs in PD patients (r=0.421, p<0.05). CONCLUSIONS Our results show the effector role of Th17 cells and MDSCs in PD pathology and shows their utility as effective biomarkers for PD diagnosis.

Effector CD4 cell tolerization is mediated through functional inactivation and involves preferential impairment of TNF-α and IFN-γ expression potentials

PubMed Central

Long, Meixiao; Higgins, Amy D.; Mihalyo, Marianne A.; Adler, Adam J.

2010-01-01

It has recently been shown that effector/memory T cells can undergo peripheral tolerization in response to self-antigen. In the present study, we found that within 24 h self-antigen profoundly impairs the ability of CD4 effectors to express TNF-α (and to a lesser extent IFN-γ); however, several days of self-antigen exposure is required to impair non-effector functions such as IL-2 expression and proliferation. Since only half of the initial effector CD4 cell population expresses effector cytokines following brief antigenic stimulation, tolerization might have been mediated either through functional inactivation of effector-competent cells, or alternatively by the selective deletion of competent and expansion of non-competent cells. When briefly stimulated effectors were fractionated based on their expression of IFN-γ, the IFN-γ− sub-population was able to express IFN-γ following secondary stimulation, indicating that all effector CD4 cells are functionally competent. Furthermore, both IFN-γ+ and IFN-γ− sub-populations underwent tolerization in response to self-HA (although the former was slightly more prone to deletion at later time points). Thus, effector CD4 cell tolerization is mediated primarily through the functional inactivation of effector-competent cells. PMID:14609577

Expression of Master Regulators of T-cell, Helper T-cell and Follicular Helper T-cell Differentiation in Angioimmunoblastic T-cell Lymphoma.

PubMed

Matsumoto, Yosuke; Nagoshi, Hisao; Yoshida, Mihoko; Kato, Seiichi; Kuroda, Junya; Shimura, Kazuho; Kaneko, Hiroto; Horiike, Shigeo; Nakamura, Shigeo; Taniwaki, Masafumi

2017-11-01

Objective It has been postulated that the normal counterpart of angioimmunoblastic T-cell lymphoma (AITL) is the follicular helper T-cell (TFH). Recent immunological studies have identified several transcription factors responsible for T-cell differentiation. The master regulators associated with T-cell, helper T-cell (Th), and TFH differentiation are reportedly BCL11B, Th-POK, and BCL6, respectively. We explored the postulated normal counterpart of AITL with respect to the expression of the master regulators of T-cell differentiation. Methods We performed an immunohistochemical analysis in 15 AITL patients to determine the expression of the master regulators and several surface markers associated with T-cell differentiation. Results BCL11B was detected in 10 patients (67%), and the surface marker of T-cells (CD3) was detected in all patients. Only 2 patients (13%) expressed the marker of naïve T-cells (CD45RA), but all patients expressed the marker of effector T-cells (CD45RO). Nine patients expressed Th-POK (60%), and 7 (47%) expressed a set of surface antigens of Th (CD4-positive and CD8-negative). In addition, BCL6 and the surface markers of TFH (CXCL13, PD-1, and SAP) were detected in 11 (73%), 8 (53%), 14 (93%), and all patients, respectively. Th-POK-positive/BCL6-negative patients showed a significantly shorter overall survival (OS) than the other patients (median OS: 33.0 months vs. 74.0 months, p=0.020; log-rank test). Conclusion Many of the AITL patients analyzed in this study expressed the master regulators of T-cell differentiation. The clarification of the diagnostic significance and pathophysiology based on the expression of these master regulators in AITL is expected in the future.

[Effects of thymosin alpha1 on immune effector molecules of mouse].

PubMed

Li, Wei-ye; Lu, Hui-min; Guo, Qiang; Hu, Wei-ming; Zhang, Zhao-da

2014-05-01

To analysis the effects of Talpha1 on the immune effector molecules in mouse immune system. Sixty five BABL/c mice were divided into four groups: CsA group (n=20), Talpha1 group (n= 20), CsA+Talpha1 group (n=20) and control group (n=5). In the 3 experimental groups, 10 mg/kg CsA, 400 microg/ kg Talpha1, 10 mg/kg CsA+400 microg/kg Talpha1 were respectively administrated by intraperitoneal injection daily. Luminex was performed for cytokine detection at 1 d, 7 d, 14 d, 21 d day after the above treatments. Lymphocyte culture was prepared with the mouse spleen suspension, and then treated with 0. 25 mg/mL CsA, 10 microg/mL Talpha1 or 0.25 mg/mL CsA+10 microg/mL Talpha1 in vitro, respectively. Three days later, OD values of each treated lymphocyte culture and several cytokines in the culture were measured. Compared with other groups, CsA+Talpha1 group had significant lower IL-1alpha, IL-2, IL-6, IL-17, and significant higher IL-10 at 1 d, 7 d, 14 d, 21 d after the treatments (P < 0.05). Three days after the culture, OD value in the control group was significantly higher than that in Talppha1 group, CsA group, and CsA+ Talpha1 group (P < 0.05). IL-1alpa and IL-6 in the control group were significantly higher than those in the experiment groups (P < 0.05), while IL-10 in the control group was significantly lower than that in the experiment groups (P < 0.05). IL-2 and IL-17 were similar. Talpha1 show regulatory effect on the immune effector molecules which could promote Th1 cells transforming to Th2 cells.

Pertussis Circulation Has Increased T-Cell Immunity during Childhood More than a Second Acellular Booster Vaccination in Dutch Children 9 Years of Age

PubMed Central

Schure, Rose-Minke; de Rond, Lia; Öztürk, Kemal; Hendrikx, Lotte; Sanders, Elisabeth; Berbers, Guy; Buisman, Anne-Marie

2012-01-01

Here we report the first evaluation of T-cell responses upon a second acellular pertussis booster vaccination in Dutch children at 9 years of age, 5 years after a preschool booster vaccination. Blood samples of children 9 years of age were studied longitudinally until 1 year after the second aP booster and compared with those after the first aP booster in children 4 and 6 years of age from a cross-sectional study. After stimulation with pertussis-vaccine antigens, Th1, Th2 and Th17 cytokine responses were measured and effector memory cells (CCR7-CD45RA-) were characterized by 8-colour FACS analysis. The second aP booster vaccination at pre-adolescent age in wP primed individuals did increase pertussis-specific Th1 and Th2 cytokine responses. Noticeably, almost all T-cell responses had increased with age and were already high before the booster vaccination at 9 years of age. The enhancement of T-cell immunity during the 5 year following the booster at 4 years of age is probably caused by natural boosting due to the a high circulation of pertussis. However, the incidence of pertussis is high in adolescents and adults who have only received the Dutch wP vaccine during infancy and no booster at 4 years of age. Therefore, an aP booster vaccination at adolescence or later in these populations might improve long-term immunity against pertussis and reduce the transmission to the vulnerable newborns. Trial Registration Controlled-Trials.com ISRCTN64117538 PMID:22860033

Excessive expression of miR-27 impairs Treg-mediated immunological tolerance

PubMed Central

Cruz, Leilani O.; Hashemifar, Somaye Sadat; Wu, Cheng-Jang; Cho, Sunglim; Nguyen, Duc T.; Lin, Ling-Li; Khan, Aly Azeem

2017-01-01

MicroRNAs (miRs) are tightly regulated in the immune system, and aberrant expression of miRs often results in hematopoietic malignancies and autoimmune diseases. Previously, it was suggested that elevated levels of miR-27 in T cells isolated from patients with multiple sclerosis facilitate disease progression by inhibiting Th2 immunity and promoting pathogenic Th1 responses. Here we have demonstrated that, although mice with T cell–specific overexpression of miR-27 harbor dysregulated Th1 responses and develop autoimmune pathology, these disease phenotypes are not driven by miR-27 in effector T cells in a cell-autonomous manner. Rather, dysregulation of Th1 responses and autoimmunity resulted from a perturbed Treg compartment. Excessive miR-27 expression in murine T cells severely impaired Treg differentiation. Moreover, Tregs with exaggerated miR-27–mediated gene regulation exhibited diminished homeostasis and suppressor function in vivo. Mechanistically, we determined that miR-27 represses several known as well as previously uncharacterized targets that play critical roles in controlling multiple aspects of Treg biology. Collectively, our data show that miR-27 functions as a key regulator in Treg development and function and suggest that proper regulation of miR-27 is pivotal to safeguarding Treg-mediated immunological tolerance. PMID:28067667

Leptin receptor signaling in T cells is required for Th17 differentiation.

PubMed

Reis, Bernardo S; Lee, Kihyun; Fanok, Melania H; Mascaraque, Cristina; Amoury, Manal; Cohn, Lillian B; Rogoz, Aneta; Dallner, Olof S; Moraes-Vieira, Pedro M; Domingos, Ana I; Mucida, Daniel

2015-06-01

The hormone leptin plays a key role in energy homeostasis, and the absence of either leptin or its receptor (LepR) leads to severe obesity and metabolic disorders. To avoid indirect effects and to address the cell-intrinsic role of leptin signaling in the immune system, we conditionally targeted LepR in T cells. In contrast with pleiotropic immune disorders reported in obese mice with leptin or LepR deficiency, we found that LepR deficiency in CD4(+) T cells resulted in a selective defect in both autoimmune and protective Th17 responses. Reduced capacity for differentiation toward a Th17 phenotype by lepr-deficient T cells was attributed to reduced activation of the STAT3 and its downstream targets. This study establishes cell-intrinsic roles for LepR signaling in the immune system and suggests that leptin signaling during T cell differentiation plays a crucial role in T cell peripheral effector function. Copyright © 2015 by The American Association of Immunologists, Inc.

A Nonsecosteroidal Vitamin D Receptor Modulator Ameliorates Experimental Autoimmune Encephalomyelitis without Causing Hypercalcemia

PubMed Central

Na, Songqing; Ma, Yanfei; Zhao, Jingyong; Schmidt, Clint; Zeng, Qing Q.; Chandrasekhar, Srinivasan; Chin, William W.; Nagpal, Sunil

2011-01-01

Vitamin D receptor (VDR) agonists are currently the agents of choice for the treatment of psoriasis, a skin inflammatory indication that is believed to involve an autoimmune component. 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], the biologically active metabolite of vitamin D, has shown efficacy in animal autoimmune disease models of multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, and type I diabetes. However, the side effect of 1,25-(OH)2D3 and its synthetic secosteroidal analogs is hypercalcemia, which is a major impediment in their clinical development for autoimmune diseases. Hypercalcemia develops as a result of the action of VDR agonists on the intestine. Here, we describe the identification of a VDR modulator (VDRM) compound A that was transcriptionally less active in intestinal cells and as a result exhibited less calcemic activity in vivo than 1,25-(OH)2D3. Cytokine analysis indicated that the VDRM not only modulated the T-helper cell balance from Th1 to Th2 effector function but also inhibited Th17 differentiation. Finally, we demonstrate that the oral administration of compound A inhibited the induction and progress of experimental autoimmune encephalomyelitis in mice without causing hypercalcemia. PMID:21318047

T helper type 17 cells contribute to anti-tumour immunity and promote the recruitment of T helper type 1 cells to the tumour.

PubMed

Nuñez, Sarah; Saez, Juan Jose; Fernandez, Dominique; Flores-Santibañez, Felipe; Alvarez, Karla; Tejon, Gabriela; Ruiz, Paulina; Maldonado, Paula; Hidalgo, Yessia; Manriquez, Valeria; Bono, Maria Rosa; Rosemblatt, Mario; Sauma, Daniela

2013-05-01

T helper type 17 (Th17) lymphocytes are found in high frequency in tumour-burdened animals and cancer patients. These lymphocytes, characterized by the production of interleukin-17 and other pro-inflammatory cytokines, have a well-defined role in the development of inflammatory and autoimmune pathologies; however, their function in tumour immunity is less clear. We explored possible opposing anti-tumour and tumour-promoting functions of Th17 cells by evaluating tumour growth and the ability to promote tumour infiltration of myeloid-derived suppressor cells (MDSC), regulatory T cells and CD4(+)  interferon-γ(+) cells in a retinoic acid-like orphan receptor γt (RORγt) -deficient mouse model. A reduced percentage of Th17 cells in the tumour microenvironment in RORγt-deficient mice led to enhanced tumour growth, that could be reverted by adoptive transfer of Th17 cells. Differences in tumour growth were not associated with changes in the accumulation or suppressive function of MDSC and regulatory T cells but were related to a decrease in the proportion of CD4(+) T cells in the tumour. Our results suggest that Th17 cells do not affect the recruitment of immunosuppressive populations but favour the recruitment of effector Th1 cells to the tumour, thereby promoting anti-tumour responses. © 2012 Blackwell Publishing Ltd.

Genomics of Alzheimer Disease: A Review.

PubMed

Rosenberg, Roger N; Lambracht-Washington, Doris; Yu, Gang; Xia, Weiming

2016-07-01

To provide a comprehensive review of knowledge of the genomics of Alzheimer disease (AD) and DNA amyloid β 42 (Aβ42) vaccination as a potential therapy. Genotype-phenotype correlations of AD are presented to provide a comprehensive appreciation of the spectrum of disease causation. Alzheimer disease is caused in part by the overproduction and lack of clearance of Aβ protein. Oligomer Aβ, the most toxic species of Aβ, causes direct injury to neurons, accompanied by enhanced neuroinflammation, astrocytosis and gliosis, and eventually neuronal loss. The strongest genetic evidence supporting this hypothesis derives from mutations in the amyloid precursor protein (APP) gene. A detrimental APP mutation at the β-secretase cleavage site linked to early-onset AD found in a Swedish pedigree enhances Aβ production, in contrast to a beneficial mutation 2 residues away in APP that reduces Aβ production and protects against the onset of sporadic AD. A number of common variants associated with late-onset AD have been identified including apolipoprotein E, BIN1, ABC7, PICALM, MS4A4E/MS4A6A, CD2Ap, CD33, EPHA1, CLU, CR1, and SORL1. One or 2 copies of the apolipoprotein E ε4 allele are a major risk factor for late-onset AD. With DNA Aβ42 vaccination, a Th2-type noninflammatory immune response was achieved with a downregulation of Aβ42-specific effector (Th1, Th17, and Th2) cell responses at later immunization times. DNA Aβ42 vaccination upregulated T regulator cells (CD4+, CD25+, and FoxP3+) and its cytokine interleukin 10, resulting in downregulation of T effectors. Mutations in APP and PS-1 and PS-2 genes that are associated with early-onset, autosomal, dominantly inherited AD, in addition to the at-risk gene polymorphisms responsible for late-onset AD, all indicate a direct and early role of Aβ in the pathogenesis of AD. A translational result of genomic research has been Aβ-reducing therapies including DNA Aβ42 vaccination as a promising approach to delay or prevent this disease.

Multiple host defense defects in failure of C57BL/6 ep/ep (pale ear) mice to resolve visceral Leishmania donovani infection.

PubMed Central

Murray, H W; Hariprashad, J; McDermott, D F; Stoeckle, M Y

1996-01-01

Euthymic C57BL/L ep/ep (pale ear [PE]) mice halt the visceral replication of intracellular Leishmania donovani but fail to properly resolve infection. A previous study identified an isolated defect in tissue granuloma formation in these mice; CD4+ and CD8+ cell number, gamma interferon (IFN-gamma) production, and macrophage antimicrobial activity in vitro were all intact. New in vivo results reported here suggest a considerably more complex immune defect, with evidence indicating (i) enhanced control over L. donovani after transfer of normal C57BL/6 spleen cells, (ii) a partially suppressive Th2 cell-associated response mediated by interleukin-4 (IL-4) but not reversed by CD4+ cell depletion, (iii) absent responses to endogenous Th1 cell lymphokines (IFN-gamma and IL-2) but preserved responsiveness to endogenous tumor necrosis factor alpha, (iv) absent responses to exogenous treatment with recognized antileishmanial cytokines (IFN-gamma, IL-2, IL-12, and granulocyte-macrophage colony-stimulating factor [GM-CSF]) not corrected by transfer of C57BL/6 spleen cells, and (v) a deficient response to antimony chemotherapy. Defective hepatic granuloma formation was not corrected by transfer of C57BL/6 spleen cells or by anti-IL-4 administration. While treatment with IL-2 and GM-CSF modified the tissue reaction and induced selected effector cells to encase tissue macrophages, no antileishmanial activity resulted. Together, these observations suggest that the failure of PE mice to resolve visceral L. donovani infection likely represents expression of multiple suboptimal immune responses and/or partial defects, probably involving a combination of T-cell dysfunction, a Th2 cell response, and target cell (macrophage) hyporesponsiveness. PMID:8557335

Monocyte-derived dendritic cells induce a house dust mite-specific Th2 allergic inflammation in the lung of humanized SCID mice: involvement of CCR7.

PubMed

Hammad, Hamida; Lambrecht, Bart N; Pochard, Pierre; Gosset, Philippe; Marquillies, Philippe; Tonnel, André-Bernard; Pestel, Joël

2002-08-01

In rodents, airway dendritic cells (DCs) capture inhaled Ag, undergo maturation, and migrate to the draining mediastinal lymph nodes (MLN) to initiate the Ag-specific T cell response. However, the role of human DCs in the pathogenesis of the Th2 cell-mediated disease asthma remains to be clarified. Here, by using SCID mice engrafted with T cells from either house dust mite (HDM)-allergic patients or healthy donors, we show that DCs pulsed with Der p 1, one of the major allergens of HDM, and injected intratracheally into naive animals migrated into the MLN. In the MLN, Der p 1-pulsed DCs from allergic patients induced the proliferation of IL-4-producing CD4(+) T cells, whereas those from healthy donors induced IFN-gamma-secreting cells. In reconstituted human PBMC-reconstituted SCID mice primed with pulsed DCs from allergic patients, repeated exposure to aerosols of HDM induced 1) a strong pulmonary inflammatory reaction rich in T cells and eosinophils, 2) an increase in IL-4 and IL-5 production in the lung lavage fluid, and 3) increased IgE production compared with that in mice primed with unpulsed DCs. All these effects were reduced following in vivo neutralization of the CCR7 ligand secondary lymphoid tissue chemokine. These data in human PBMC-reconstituted SCID mice show that monocyte-derived DCs might play a key role in the pathogenesis of the pulmonary allergic response by inducing Th2 effector function following migration to the MLN.

Absence of the common gamma chain (γ(c)), a critical component of the Type I IL-4 receptor, increases the severity of allergic lung inflammation.

PubMed

Dasgupta, Preeta; Qi, Xiulan; Smith, Elizabeth P; Keegan, Achsah D

2013-01-01

The T(H)2 cytokines, IL-4 and IL-13, play critical roles in inducing allergic lung inflammation and drive the alternative activation of macrophages (AAM). Although both cytokines share receptor subunits, IL-4 and IL-13 have differential roles in asthma pathogenesis: IL-4 regulates T(H)2 cell differentiation, while IL-13 regulates airway hyperreactivity and mucus production. Aside from controlling T(H)2 differentiation, the unique contribution of IL-4 signaling via the Type I receptor in airway inflammation remains unclear. Therefore, we analyzed responses in mice deficient in gamma c (γ(c)) to elucidate the role of the Type I IL-4 receptor. OVA primed CD4⁺ OT-II T cells were adoptively transferred into RAG2⁻/⁻ and γ(c)⁻/⁻ mice and allergic lung disease was induced. Both γ(c)⁻/⁻ and γcxRAG2⁻/⁻ mice developed increased pulmonary inflammation and eosinophilia upon OVA challenge, compared to RAG2⁻/⁻ mice. Characteristic AAM proteins FIZZ1 and YM1 were expressed in lung epithelial cells in both mouse strains, but greater numbers of FIZZ1+ or YM1+ airways were present in γ(c)⁻/⁻ mice. Absence of γc in macrophages, however, resulted in reduced YM1 expression. We observed higher T(H)2 cytokine levels in the BAL and an altered DC phenotype in the γ(c)⁻/⁻ recipient mice suggesting the potential for dysregulated T cell and dendritic cell (DC) activation in the γ(c)-deficient environment. These results demonstrate that in absence of the Type I IL-4R, the Type II R can mediate allergic responses in the presence of T(H)2 effectors. However, the Type I R regulates AAM protein expression in macrophages.

Transcription factor interplay in T helper cell differentiation

PubMed Central

Evans, Catherine M.

2013-01-01

The differentiation of CD4 helper T cells into specialized effector lineages has provided a powerful model for understanding immune cell differentiation. Distinct lineages have been defined by differential expression of signature cytokines and the lineage-specifying transcription factors necessary and sufficient for their production. The traditional paradigm of differentiation towards Th1 and Th2 subtypes driven by T-bet and GATA3, respectively, has been extended to incorporate additional T cell lineages and transcriptional regulators. Technological advances have expanded our view of these lineage-specifying transcription factors to the whole genome and revealed unexpected interplay between them. From these data, it is becoming clear that lineage specification is more complex and plastic than previous models might have suggested. Here, we present an overview of the different forms of transcription factor interplay that have been identified and how T cell phenotypes arise as a product of this interplay within complex regulatory networks. We also suggest experimental strategies that will provide further insight into the mechanisms that underlie T cell lineage specification and plasticity. PMID:23878131

Preferential induction of Th17 cells in vitro and in vivo by Fucogalactan from Ganoderma lucidum (Reishi).

PubMed

Yoshida, Hideyuki; Suzuki, Mayu; Sakaguchi, Ryota; Tani, Ito; Kotani, Hitoshi; Shudo, Norimasa; Yoshimura, Akihiko

2012-05-25

The mushroom known as Reishi (Ganoderma lucidum) has been used as an herbal medicine for tumor treatment and immune system activation. Because its effects on the differentiation of effector T helper cells have not yet been fully understood, we investigated the effects of Reishi and those of its principal ingredient, β-glucan, on the activation of dendritic cells and the differentiation of Th17 cells. Reishi extracts as well as purified β-glucan (Curdran) activated DCs and caused them to produce large amounts of IL-23. β-glucan also enhanced and sustained the transcription of IL-23p19. The MEK-ERK signaling pathway positively regulates IL-23p19 transcription in β-glucan-stimulated DCs. In a mixed leukocyte reaction, Reishi-stimulated DCs preferentially induced Th17 cells. Furthermore, orally-administrated Reishi increased the percentages of Th17 cells and the transcription levels of antimicrobial peptides. Our results show that Reishi and β-glucan activate DCs to produce large amounts of IL-23, which induces Th17 differentiation both in vitro and in vivo. Copyright © 2012 Elsevier Inc. All rights reserved.

Antigen-Specific Th17 Cells Are Primed by Distinct and Complementary Dendritic Cell Subsets in Oropharyngeal Candidiasis

PubMed Central

Kirchner, Florian R.; Becattini, Simone; Rülicke, Thomas; Sallusto, Federica; LeibundGut-Landmann, Salomé

2015-01-01

Candida spp. can cause severe and chronic mucocutaneous and systemic infections in immunocompromised individuals. Protection from mucocutaneous candidiasis depends on T helper cells, in particular those secreting IL-17. The events regulating T cell activation and differentiation toward effector fates in response to fungal invasion in different tissues are poorly understood. Here we generated a Candida-specific TCR transgenic mouse reactive to a novel endogenous antigen that is conserved in multiple distant species of Candida, including the clinically highly relevant C. albicans and C. glabrata. Using TCR transgenic T cells in combination with an experimental model of oropharyngeal candidiasis (OPC) we investigated antigen presentation and Th17 priming by different subsets of dendritic cells (DCs) present in the infected oral mucosa. Candida-derived endogenous antigen accesses the draining lymph nodes and is directly presented by migratory DCs. Tissue-resident Flt3L-dependent DCs and CCR2-dependent monocyte-derived DCs collaborate in antigen presentation and T cell priming during OPC. In contrast, Langerhans cells, which are also present in the oral mucosa and have been shown to prime Th17 cells in the skin, are not required for induction of the Candida-specific T cell response upon oral challenge. This highlights the functional compartmentalization of specific DC subsets in different tissues. These data provide important new insights to our understanding of tissue-specific antifungal immunity. PMID:26431538

In Planta Functional Analysis and Subcellular Localization of the Oomycete Pathogen Plasmopara viticola Candidate RXLR Effector Repertoire

PubMed Central

Liu, Yunxiao; Lan, Xia; Song, Shiren; Yin, Ling; Dry, Ian B.; Qu, Junjie; Xiang, Jiang; Lu, Jiang

2018-01-01

Downy mildew is one of the most destructive diseases of grapevine, causing tremendous economic loss in the grape and wine industry. The disease agent Plasmopara viticola is an obligate biotrophic oomycete, from which over 100 candidate RXLR effectors have been identified. In this study, 83 candidate RXLR effector genes (PvRXLRs) were cloned from the P. viticola isolate “JL-7-2” genome. The results of the yeast signal sequence trap assay indicated that most of the candidate effectors are secretory proteins. The biological activities and subcellular localizations of all the 83 effectors were analyzed via a heterologous Agrobacterium-mediated Nicotiana benthamiana expression system. Results showed that 52 effectors could completely suppress cell death triggered by elicitin, 10 effectors could partially suppress cell death, 11 effectors were unable to suppress cell death, and 10 effectors themselves triggered cell death. Live-cell imaging showed that the majority of the effectors (76 of 83) could be observed with informative fluorescence signals in plant cells, among which 34 effectors were found to be targeted to both the nucleus and cytosol, 29 effectors were specifically localized in the nucleus, and 9 effectors were targeted to plant membrane system. Interestingly, three effectors PvRXLR61, 86 and 161 were targeted to chloroplasts, and one effector PvRXLR54 was dually targeted to chloroplasts and mitochondria. However, western blot analysis suggested that only PvRXLR86 carried a cleavable N-terminal transit peptide and underwent processing in planta. Many effectors have previously been predicted to target organelles, however, to the best of our knowledge, this is the first study to provide experimental evidence of oomycete effectors targeted to chloroplasts and mitochondria. PMID:29706971

Spontaneous cytotoxic earthworm leukocytes kill K562 tumor cells.

PubMed

Suzuki, M M; Cooper, E L

1995-08-01

Earthworm coelomocytes may act as effector cells which destroy targets in vitro. In a 51Cr release assay, Lumbricus coelomocyte effectors showed lytic activities of 3-14% against K562 human tumor cells when incubated 1-4 hr at 23 degrees C or 37 degrees C. Cytotoxicity was correlated with effector: target ratio. However, targets were not killed by incubating them in cell-free, 0.2 micron filtered coelomic fluid. The supernatant from coelomocytes cultured alone failed to kill K562 targets but coelomocyte lysates were toxic to target cells in a concentration-dependent manner. Coelomocytes were examined using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). When effectors and targets were examined under TEM, we found close apposition of effector granulocytic coelomocytes and target cell membranes but not with coelomocytes nor eleocytes at up to 15 min incubation. By SEM, effector cells appeared not only to be in close contact with targets, but instances of target lysis were observed. These results suggest that effector cell/target cell contact is essential for cytotoxicity to occur.

Cell Homogeneity Indispensable for Regenerative Medicine by Cultured Human Corneal Endothelial Cells.

PubMed

Hamuro, Junji; Toda, Munetoyo; Asada, Kazuko; Hiraga, Asako; Schlötzer-Schrehardt, Ursula; Montoya, Monty; Sotozono, Chie; Ueno, Morio; Kinoshita, Shigeru

2016-09-01

To identify the subpopulation (SP) among heterogeneous cultured human corneal endothelial cells (cHCECs) devoid of cell-state transition applicable for cell-based therapy. Subpopulation presence in cHCECs was confirmed via surface CD-marker expression level by flow cytometry. CD markers effective for distinguishing distinct SPs were selected by analyzing those on established cHCECs with a small cell area and high cell density. Contrasting features among three typical cHCEC SPs was confirmed by PCR array for extracellular matrix (ECM). Combined analysis of CD markers was performed to identify the SP (effector cells) applicable for therapy. ZO-1 and Na+/K+ ATPase, CD200, and HLA expression were compared among heterogeneous SPs. Flow cytometry analysis identified the effector cell expressing CD166+CD105-CD44-∼+/-CD26-CD24-, but CD200-, and the presence of other SPs with CD166+ CD105-CD44+++ (CD26 and CD24, either + or -) was confirmed. PCR array revealed three distinct ECM expression profiles. Some SPs expressed ZO-1 and Na+/K+ ATPase at comparable levels with effector cells, while only one SP expressed CD200, but not on effector cells. Human leukocyte antigen expression was most reduced in the effector SP. The proportion of effector cells (E-ratio) inversely paralleled donor age and decreased during prolonged culture passages. The presence of Rho-associated protein kinase (ROCK) inhibitor increased the E-ratio in cHCECs. The average area of effector cells was approximately 200∼220 μm2, and the density of cHCECs exceeded 2500 cells/mm2. A specified cultured effector cell population sharing the surface phenotypes with mature HCECs in corneal tissues may serve as an alternative to donor corneas for the treatment of corneal endothelial dysfunction.

Oridonin's therapeutic effect: suppressing Th1/Th17 simultaneously in a mouse model of Crohn's disease.

PubMed

Wang, Shubei; Zhang, Yong; Saas, Philippe; Wang, Haili; Xu, Ying; Chen, Ke; Zhong, Jie; Yuan, Yaozong; Wang, Ying; Sun, Yunwei

2015-03-01

Crohn's disease is a chronic inflammatory bowel disease. Oridonin is an effective component isolated from Rabdosia rubescens. It can inhibit the activation of transcription factor nuclear factor-kappa B and suppress the over expression of cytokines. We postulated that oridonin may be a potential therapeutic candidate for Crohn's disease. To confirm the postulation, we investigated clinical and immunologic modulations of oridonin in a mouse model of trinitrobenzene sulfonic acid-induced colitis. It was found that oridonin attenuated trinitrobenzene sulfonic acid-induced colitis as represented by a reduction in colonic interferon-γ/inteleukin-17 secretion and a decrement in splenic Th1/Th17 cells and effector memory CD4(+) T cells. Oridonin treatment inhibited the proliferation of CD4(+) T cells and upregulated the apoptosis of lymphocytes by inhibiting nuclear translocation of transcription factor nuclear factor-kappa B. Oridonin is a potential modulator for trinitrobenzene sulfonic acid-induced colitis and other Th1/Th17 mediated inflammatory diseases. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

CD4 T cells play important roles in maintaining IL-17-producing γδ T-cell subsets in naive animals.

PubMed

Do, Jeong-Su; Visperas, Anabelle; O'Brien, Rebecca L; Min, Booki

2012-04-01

A proportional balance between αβ and γδ T-cell subsets in the periphery is exceedingly well maintained by a homeostatic mechanism. However, a cellular mechanism underlying the regulation remains undefined. We recently reported that a subset of developing γδ T cells spontaneously acquires interleukin (IL)-17-producing capacity even within naive animals through a transforming growth factor (TGF)β1-dependent mechanism, thus considered 'innate' IL-17-producing cells. Here, we report that γδ T cells generated within αβ T cell (or CD4 T cell)-deficient environments displayed altered cytokine profiles; particularly, 'innate' IL-17 expression was significantly impaired compared with those in wild-type mice. Impaired IL-17 production in γδ T cells was directly related to CD4 T-cell deficiency, because depletion of CD4 T cells in wild-type mice diminished and adoptive CD4 T-cell transfer into T-cell receptor β-/- mice restored IL-17 expression in γδ T cells. CD4 T cell-mediated IL-17 expression required TGFβ1. Moreover, Th17 but not Th1 or Th2 effector CD4 T cells were highly efficient in enhancing γδ T-cell IL-17 expression. Taken together, our results highlight a novel CD4 T cell-dependent mechanism that shapes the generation of IL-17+ γδ T cells in naive settings.

Dynamic balance between master transcription factors determines the fates and functions of CD4 T cell and innate lymphoid cell subsets

PubMed Central

2017-01-01

CD4 T cells, including T regulatory cells (Treg cells) and effector T helper cells (Th cells), and recently identified innate lymphoid cells (ILCs) play important roles in host defense and inflammation. Both CD4 T cells and ILCs can be classified into distinct lineages based on their functions and the expression of lineage-specific genes, including those encoding effector cytokines, cell surface markers, and key transcription factors. It was first recognized that each lineage expresses a specific master transcription factor and the expression of these factors is mutually exclusive because of cross-regulation among these factors. However, recent studies indicate that the master regulators are often coexpressed. Furthermore, the expression of master regulators can be dynamic and quantitative. In this review, we will first discuss similarities and differences between the development and functions of CD4 T cell and ILC subsets and then summarize recent literature on quantitative, dynamic, and cell type–specific balance between the master transcription factors in determining heterogeneity and plasticity of these subsets. PMID:28630089

Reduced PU.1 expression underlies aberrant neutrophil maturation and function in β-thalassemia mice and patients.

PubMed

Siwaponanan, Panjaree; Siegers, Jurre Ynze; Ghazali, Razi; Ng, Thian; McColl, Bradley; Ng, Garrett Zhen-Wei; Sutton, Philip; Wang, Nancy; Ooi, Isabelle; Thiengtavor, Chayada; Fucharoen, Suthat; Chaichompoo, Pornthip; Svasti, Saovaros; Wijburg, Odilia; Vadolas, Jim

2017-06-08

β-Thalassemia is associated with several abnormalities of the innate immune system. Neutrophils in particular are defective, predisposing patients to life-threatening bacterial infections. The molecular and cellular mechanisms involved in impaired neutrophil function remain incompletely defined. We used the Hbb th3/+ β-thalassemia mouse and hemoglobin E (HbE)/β-thalassemia patients to investigate dysregulated neutrophil activity. Mature neutrophils from Hbb th3/+ mice displayed a significant reduction in chemotaxis, opsonophagocytosis, and production of reactive oxygen species, closely mimicking the defective immune functions observed in β-thalassemia patients. In Hbb th3/+ mice, the expression of neutrophil CXCR2, CD11b, and reduced NAD phosphate oxidase components (p22phox, p67phox, and gp91phox) were significantly reduced. Morphological analysis of Hbb th3/+ neutrophils showed that a large percentage of mature phenotype neutrophils (Ly6G hi Ly6C low ) appeared as band form cells, and a striking expansion of immature (Ly6G low Ly6C low ) hyposegmented neutrophils, consisting mainly of myelocytes and metamyelocytes, was noted. Intriguingly, expression of an essential mediator of neutrophil terminal differentiation, the ets transcription factor PU.1, was significantly decreased in Hbb th3/+ neutrophils. In addition, in vivo infection with Streptococcus pneumoniae failed to induce PU.1 expression or upregulate neutrophil effector functions in Hbb th3/+ mice. Similar changes to neutrophil morphology and PU.1 expression were observed in splenectomized and nonsplenectomized HbE/β-thalassemia patients. This study provides a mechanistic insight into defective neutrophil maturation in β-thalassemia patients, which contributes to deficiencies in neutrophil effector functions. © 2017 by The American Society of Hematology.

Mitochondrial Ca2+ and membrane potential, an alternative pathway for Interleukin 6 to regulate CD4 cell effector function

PubMed Central

Yang, Rui; Lirussi, Dario; Thornton, Tina M; Jelley-Gibbs, Dawn M; Diehl, Sean A; Case, Laure K; Madesh, Muniswamy; Taatjes, Douglas J; Teuscher, Cory; Haynes, Laura; Rincón, Mercedes

2015-01-01

IL-6 plays an important role in determining the fate of effector CD4 cells and the cytokines that these cells produce. Here we identify a novel molecular mechanism by which IL-6 regulates CD4 cell effector function. We show that IL-6-dependent signal facilitates the formation of mitochondrial respiratory chain supercomplexes to sustain high mitochondrial membrane potential late during activation of CD4 cells. Mitochondrial hyperpolarization caused by IL-6 is uncoupled from the production of ATP by oxidative phosphorylation. However, it is a mechanism to raise the levels of mitochondrial Ca2+ late during activation of CD4 cells. Increased levels of mitochondrial Ca2+ in the presence of IL-6 are used to prolong Il4 and Il21 expression in effector CD4 cells. Thus, the effect of IL-6 on mitochondrial membrane potential and mitochondrial Ca2+ is an alternative pathway by which IL-6 regulates effector function of CD4 cells and it could contribute to the pathogenesis of inflammatory diseases. DOI: http://dx.doi.org/10.7554/eLife.06376.001 PMID:25974216

Human Cytomegalovirus (HCMV)-Specific CD4+ T Cells Are Polyfunctional and Can Respond to HCMV-Infected Dendritic Cells In Vitro

PubMed Central

Sedikides, George X.; Mason, Gavin M.; Okecha, Georgina

2017-01-01

ABSTRACT Human cytomegalovirus (HCMV) infection and periodic reactivation are generally well controlled by the HCMV-specific T cell response in healthy people. While the CD8+ T cell response to HCMV has been extensively studied, the HCMV-specific CD4+ T cell effector response is not as well understood, especially in the context of direct interactions with HCMV-infected cells. We screened the gamma interferon (IFN-γ) and interleukin-10 (IL-10) responses to 6 HCMV peptide pools (pp65, pp71, IE1, IE2, gB, and US3, selected because they were the peptides most frequently responded to in our previous studies) in 84 donors aged 23 to 74 years. The HCMV-specific CD4+ T cell response to pp65, IE1, IE2, and gB was predominantly Th1 biased, with neither the loss nor the accumulation of these responses occurring with increasing age. A larger proportion of donors produced an IL-10 response to pp71 and US3, but the IFN-γ response was still dominant. CD4+ T cells specific to the HCMV proteins studied were predominantly effector memory cells and produced both cytotoxic (CD107a expression) and cytokine (macrophage inflammatory protein 1β secretion) effector responses. Importantly, when we measured the CD4+ T cell response to cytomegalovirus (CMV)-infected dendritic cells in vitro, we observed that the CD4+ T cells produced a range of cytotoxic and secretory effector functions, despite the presence of CMV-encoded immune evasion molecules. CD4+ T cell responses to HCMV-infected dendritic cells were sufficient to control the dissemination of virus in an in vitro assay. Together, the results show that HCMV-specific CD4+ T cell responses, even those from elderly individuals, are highly functional and are directly antiviral. IMPORTANCE Human cytomegalovirus (HCMV) infection is carried for a lifetime and in healthy people is kept under control by the immune system. HCMV has evolved many mechanisms to evade the immune response, possibly explaining why the virus is never eliminated during the host's lifetime. The dysfunction of immune cells associated with the long-term carriage of HCMV has been linked with poor responses to new pathogens and vaccines when people are older. In this study, we investigated the response of a subset of immune cells (CD4+ T cells) to HCMV proteins in healthy donors of all ages, and we demonstrate that the functionality of CD4+ T cells is maintained. We also show that CD4+ T cells produce effector functions in response to HCMV-infected cells and can prevent virus spread. Our work demonstrates that these HCMV-specific immune cells retain many important functions and help to prevent deleterious HCMV disease in healthy older people. PMID:28053099

Human Cytomegalovirus (HCMV)-Specific CD4+ T Cells Are Polyfunctional and Can Respond to HCMV-Infected Dendritic Cells In Vitro.

PubMed

Jackson, Sarah E; Sedikides, George X; Mason, Gavin M; Okecha, Georgina; Wills, Mark R

2017-03-15

Human cytomegalovirus (HCMV) infection and periodic reactivation are generally well controlled by the HCMV-specific T cell response in healthy people. While the CD8 + T cell response to HCMV has been extensively studied, the HCMV-specific CD4 + T cell effector response is not as well understood, especially in the context of direct interactions with HCMV-infected cells. We screened the gamma interferon (IFN-γ) and interleukin-10 (IL-10) responses to 6 HCMV peptide pools (pp65, pp71, IE1, IE2, gB, and US3, selected because they were the peptides most frequently responded to in our previous studies) in 84 donors aged 23 to 74 years. The HCMV-specific CD4 + T cell response to pp65, IE1, IE2, and gB was predominantly Th1 biased, with neither the loss nor the accumulation of these responses occurring with increasing age. A larger proportion of donors produced an IL-10 response to pp71 and US3, but the IFN-γ response was still dominant. CD4 + T cells specific to the HCMV proteins studied were predominantly effector memory cells and produced both cytotoxic (CD107a expression) and cytokine (macrophage inflammatory protein 1β secretion) effector responses. Importantly, when we measured the CD4 + T cell response to cytomegalovirus (CMV)-infected dendritic cells in vitro , we observed that the CD4 + T cells produced a range of cytotoxic and secretory effector functions, despite the presence of CMV-encoded immune evasion molecules. CD4 + T cell responses to HCMV-infected dendritic cells were sufficient to control the dissemination of virus in an in vitro assay. Together, the results show that HCMV-specific CD4 + T cell responses, even those from elderly individuals, are highly functional and are directly antiviral. IMPORTANCE Human cytomegalovirus (HCMV) infection is carried for a lifetime and in healthy people is kept under control by the immune system. HCMV has evolved many mechanisms to evade the immune response, possibly explaining why the virus is never eliminated during the host's lifetime. The dysfunction of immune cells associated with the long-term carriage of HCMV has been linked with poor responses to new pathogens and vaccines when people are older. In this study, we investigated the response of a subset of immune cells (CD4 + T cells) to HCMV proteins in healthy donors of all ages, and we demonstrate that the functionality of CD4 + T cells is maintained. We also show that CD4 + T cells produce effector functions in response to HCMV-infected cells and can prevent virus spread. Our work demonstrates that these HCMV-specific immune cells retain many important functions and help to prevent deleterious HCMV disease in healthy older people. Copyright © 2017 American Society for Microbiology.

Translocation of Magnaporthe oryzae effectors into rice cells and their subsequent cell-to-cell movement.

PubMed

Khang, Chang Hyun; Berruyer, Romain; Giraldo, Martha C; Kankanala, Prasanna; Park, Sook-Young; Czymmek, Kirk; Kang, Seogchan; Valent, Barbara

2010-04-01

Knowledge remains limited about how fungal pathogens that colonize living plant cells translocate effector proteins inside host cells to regulate cellular processes and neutralize defense responses. To cause the globally important rice blast disease, specialized invasive hyphae (IH) invade successive living rice (Oryza sativa) cells while enclosed in host-derived extrainvasive hyphal membrane. Using live-cell imaging, we identified a highly localized structure, the biotrophic interfacial complex (BIC), which accumulates fluorescently labeled effectors secreted by IH. In each newly entered rice cell, effectors were first secreted into BICs at the tips of the initially filamentous hyphae in the cell. These tip BICs were left behind beside the first-differentiated bulbous IH cells as the fungus continued to colonize the host cell. Fluorescence recovery after photobleaching experiments showed that the effector protein PWL2 (for prevents pathogenicity toward weeping lovegrass [Eragrostis curvula]) continued to accumulate in BICs after IH were growing elsewhere. PWL2 and BAS1 (for biotrophy-associated secreted protein 1), BIC-localized secreted proteins, were translocated into the rice cytoplasm. By contrast, BAS4, which uniformly outlines the IH, was not translocated into the host cytoplasm. Fluorescent PWL2 and BAS1 proteins that reached the rice cytoplasm moved into uninvaded neighbors, presumably preparing host cells before invasion. We report robust assays for elucidating the molecular mechanisms that underpin effector secretion into BICs, translocation to the rice cytoplasm, and cell-to-cell movement in rice.

Hair regrowth in alopecia areata patients following Stem Cell Educator therapy.

PubMed

Li, Yanjia; Yan, Baoyong; Wang, Hepeng; Li, Heng; Li, Quanhai; Zhao, Dong; Chen, Yana; Zhang, Ye; Li, Wenxia; Zhang, Jun; Wang, Shanfeng; Shen, Jie; Li, Yunxiang; Guindi, Edward; Zhao, Yong

2015-04-20

Alopecia areata (AA) is one of the most common autoimmune diseases and targets the hair follicles, with high impact on the quality of life and self-esteem of patients due to hair loss. Clinical management and outcomes are challenged by current limited immunosuppressive and immunomodulating regimens. We have developed a Stem Cell Educator therapy in which a patient's blood is circulated through a closed-loop system that separates mononuclear cells from the whole blood, allows the cells to briefly interact with adherent human cord blood-derived multipotent stem cells (CB-SC), and returns the "educated" autologous cells to the patient's circulation. In an open-label, phase 1/phase 2 study, patients (N = 9) with severe AA received one treatment with the Stem Cell Educator therapy. The median age was 20 years (median alopecic duration, 5 years). Clinical data demonstrated that patients with severe AA achieved improved hair regrowth and quality of life after receiving Stem Cell Educator therapy. Flow cytometry revealed the up-regulation of Th2 cytokines and restoration of balancing Th1/Th2/Th3 cytokine production in the peripheral blood of AA subjects. Immunohistochemistry indicated the formation of a "ring of transforming growth factor beta 1 (TGF-β1)" around the hair follicles, leading to the restoration of immune privilege of hair follicles and the protection of newly generated hair follicles against autoimmune destruction. Mechanistic studies revealed that co-culture with CB-SC may up-regulate the expression of coinhibitory molecules B and T lymphocyte attenuator (BTLA) and programmed death-1 receptor (PD-1) on CD8β(+)NKG2D(+) effector T cells and suppress their proliferation via herpesvirus entry mediator (HVEM) ligands and programmed death-1 ligand (PD-L1) on CB-SCs. Current clinical data demonstrated the safety and efficacy of the Stem Cell Educator therapy for the treatment of AA. This innovative approach produced lasting improvement in hair regrowth in subjects with moderate or severe AA. ClinicalTrials.gov, NCT01673789, 21 August 2012.

Rheumatoid arthritis patients exhibit impaired Candida albicans-specific Th17 responses.

PubMed

Bishu, Shrinivas; Su, Ee Wern; Wilkerson, Erich R; Reckley, Kelly A; Jones, Donald M; McGeachy, Mandy J; Gaffen, Sarah L; Levesque, Marc C

2014-02-11

Accumulating data implicate the CD4+ T cell subset (Th17 cells) in rheumatoid arthritis (RA). IL-17 is an inflammatory cytokine that induces tumor necrosis factor (TNF)α, IL-1β and IL-6, all of which are targets of biologic therapies used to treat RA. RA patients are well documented to experience more infections than age-matched controls, and biologic therapies further increase the risk of infection. The Th17/IL-17 axis is vital for immunity to fungi, especially the commensal fungus Candida albicans. Therefore, we were prompted to examine the relationship between RA and susceptibility to C. albicans because of the increasing interest in Th17 cells and IL-17 in driving autoimmunity, and the advent of new biologics that target this pathway. We analyzed peripheral blood and saliva from 48 RA and 33 healthy control subjects. To assess C. albicans-specific Th17 responses, PBMCs were co-cultured with heat-killed C. albicans extract, and IL-17A levels in conditioned supernatants were measured by ELISA. The frequency of Th17 and Th1 cells was determined by flow cytometry. As a measure of IL-17A-mediated effector responses, we evaluated C. albicans colonization rates in the oral cavity, salivary fungicidal activity and levels of the antimicrobial peptide β-defensin 2 (BD2) in saliva. Compared to controls, PBMCs from RA subjects exhibited elevated baseline production of IL-17A (P = 0.004), although they had similar capacity to produce IL-17A in response to Th17 cell differentiating cytokines (P = 0.91). However RA PBMCs secreted less IL-17A in response to C. albicans antigens (P = 0.006). Significantly more RA patients were colonized with C. albicans in the oral cavity than healthy subjects (P = 0.02). Concomitantly, RA saliva had reduced concentrations of salivary BD2 (P = 0.02). Nonetheless, salivary fungicidal activity was preserved in RA subjects (P = 0.70). RA subjects exhibit detectable impairments in oral immune responses to C. albicans, a strongly Th17-dependent opportunistic pathogen, despite an overall elevated baseline production of IL-17A.

IL-21: an executor of B cell fate.

PubMed

Konforte, Danijela; Simard, Nathalie; Paige, Christopher J

2009-02-15

IL-21 is a type I cytokine that shares the common receptor gamma-chain with IL-2, IL-4, IL-7, IL-9, and IL-15. B cells are one of the lymphoid cell types whose development and function are regulated by IL-21. Depending on the interplay with costimulatory signals and on the developmental stage of a B cell, IL-21 can induce proliferation, differentiation into Ig-producing plasma cells, or apoptosis in both mice and humans. Alone and in combination with Th cell-derived cytokines IL-21 can regulate class switch recombination to IgG, IgA, or IgE isotypes, indicating its important role in shaping the effector function of B cells. This review highlights the role of IL-21 in B cell development, function, and disease and provides some perspectives on the future studies in this area.

Intestinal helminths: a clue explaining the low incidence of inflammatory bowel diseases in Subsaharan Africa? Potential benefits and hazards of helminth therapy.

PubMed

Fiasse, René; Latinne, Dominique

2006-01-01

In their review, the authors state that the very low incidence and prevalence of IBD in sub-Saharan Africa cannot be explained by genetic factors since in Black populations of the U.S.A. and U.K., the incidence of these diseases is approaching that of the white populations. Beside helminths whose intestinal infestation is frequent in sub-Saharan Africa, other micro-organisms such as atypical mycobacteria, lactobacilli, etc, might have been reduced in Western population. This is a new variant of the Hygiene hypothesis. After Rook et al., these micro-organisms were acting as adjuvants for induction of T regulatory cells which, associated with antigen-presenting cells secrete IL-10 and TGF-beta, inhibiting the maturation of CD4 T cells to Th1 and Th2 effector cells, and consequently reducing the occurrence of Th1-mediated diseases like Crohn's disease and Th2-mediated diseases like ulcerative colitis. The effects of intestinal helminths on host immunity have been studied in Ethiopian Jews emigrated to Israel. Thorough studies before and after deworming have demonstrated that chronic helminth infestation provokes a state of chronic immune activation with anergy, reversible after deworming. Administration of ova of Trichuris suis, an helminth non pathogenic in man, has given encouraging results in the treatment o Crohn's disease and ulcerative colitis with a good safety record but long-term trials are needed since the potentially harmful effects of helminths on immunity.

Opposing effect of mesenchymal stem cells on Th1 and Th17 cell polarization according to the state of CD4+ T cell activation.

PubMed

Carrión, Flavio; Nova, Estefania; Luz, Patricia; Apablaza, Felipe; Figueroa, Fernando

2011-03-30

Mesenchymal stem cells (MSCs) are multipotent progenitors with broad immunosuppressive properties. However, their therapeutic use in autoimmune disease models has shown dissimilar effects when applied at different stages of disease. We therefore investigated the effect of the addition of MSCs on the differentiation of Th1, Treg and Th17 cells in vitro, at different states of CD4(+) T cell activation. CD4(+) T lymphocytes purified by negative selection from mouse C57BL/6 splenocytes were cultured under Th1, Th17 and Treg inducing conditions with IL-12, TGF-β+IL-6 or TGF-β, respectively. C57BL/6 bone marrow derived MSCs were added to CD4(+) T cell cultures at day 0 or after 3 days of T cell polarizing activation. Intracellular cytokines for Th1, Th17 and Treg cells were quantitated at day 6 by flow cytometry. While early addition (day 0) of MSCs suppressed all CD4(+) T cell lineages, addition at day 3 only decreased IFN-γ production by Th1 polarized cells by 64% (p<0.05) while markedly increased IL-17 production by Th17 polarized cells by 50% (p<0.05) and left IL-10 production by Treg polarized cells unchanged. MSCs exhibit their typical suppressive phenotype when added early to cell cultures in the presence of CD4(+) T cell polarizing stimuli. However, once T cell activation has occurred, MSCs show an opposite stimulating effect on Th17 cells, while leaving Treg IL-10 producing cells unchanged. These results suggest that the therapeutic use of MSCs in vivo might exert opposing effects on disease activity, according to the time of therapeutic application and the level of effector T cell activation. Copyright © 2010 Elsevier B.V. All rights reserved.

Five Xanthomonas type III effectors suppress cell death induced by components of immunity-associated MAP kinase cascades

PubMed Central

Teper, Doron; Sunitha, Sukumaran; Martin, Gregory B; Sessa, Guido

2015-01-01

Mitogen-activated protein kinase (MAPK) cascades play a fundamental role in signaling of plant immunity and mediate elicitation of cell death. Xanthomonas spp. manipulate plant signaling by using a type III secretion system to deliver effector proteins into host cells. We examined the ability of 33 Xanthomonas effectors to inhibit cell death induced by overexpression of components of MAPK cascades in Nicotiana benthamiana plants. Five effectors inhibited cell death induced by overexpression of MAPKKKα and MEK2, but not of MAP3Kϵ. In addition, expression of AvrBs1 in yeast suppressed activation of the high osmolarity glycerol MAPK pathway, suggesting that the target of this effector is conserved in eukaryotic organisms. These results indicate that Xanthomonas employs several type III effectors to suppress immunity-associated cell death mediated by MAPK cascades. PMID:26237448

Human Th17 Migration in Three-Dimensional Collagen Involves p38 MAPK.

PubMed

Kadiri, Maleck; El Azreq, Mohammed-Amine; Berrazouane, Sofiane; Boisvert, Marc; Aoudjit, Fawzi

2017-09-01

T cell migration across extracellular matrix (ECM) is an important step of the adaptive immune response but is also involved in the development of inflammatory autoimmune diseases. Currently, the molecular mechanisms regulating the motility of effector T cells in ECM are not fully understood. Activation of p38 MAPK has been implicated in T cell activation and is critical to the development of immune and inflammatory responses. In this study, we examined the implication of p38 MAPK in regulating the migration of human Th17 cells through collagen. Using specific inhibitor and siRNA, we found that p38 is necessary for human Th17 migration in three-dimensional (3D) collagen and that 3D collagen increases p38 phosphorylation. We also provide evidence that the collagen receptor, discoidin domain receptor 1 (DDR1), which promotes Th17 migration in 3D collagen, is involved in p38 activation. Together, our findings suggest that targeting DDR1/p38 MAPK pathway could be beneficial for the treatment of Th17-mediated inflammatory diseases. J. Cell. Biochem. 118: 2819-2827, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Mislocalization of SLP-76 leads to aberrant inflammatory cytokine and autoantibody production.

PubMed

Sonnenberg, Gregory F; Mangan, Paul R; Bezman, Natalie A; Sekiguchi, Debora R; Luning Prak, Eline T; Erikson, Jan; Maltzman, Jonathan S; Jordan, Martha S; Koretzky, Gary A

2010-03-18

Central and peripheral tolerance is required to prevent immune responses to self-antigens. We now present a mouse model in which wild-type (WT) SH2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) has been constitutively targeted to the membrane, where CD4+ T cells become spontaneously dysregulated and develop an inflammatory phenotype. Mice bearing membrane-targeted SLP-76 (MTS) have a partial T-cell lymphopenia and impaired signaling though the mature T-cell receptor. The CD4+ T cells that develop in these mice possess an activated-like phenotype and are skewed toward the inflammatory T(H)1 and T(H)17 lineages. MTS mice also spontaneously develop autoantibodies at an early age. To rule out abnormal thymic selection as the sole cause of the MTS phenotype, we expressed WT SLP-76 along with the MTS followed by deletion of the WT allele in peripheral T cells. The peripheral MTS-expressing T cells demonstrate skewed cytokine responses when transferred into lymphopenic hosts. Thus, the abnormal effector T-cell phenotype still occurs in the presence of preserved central and peripheral tolerance, suggesting that diminished T-cell receptor signaling can promote skewed T-cell responses.

Food and Natural Materials Target Mechanisms to Effectively Regulate Allergic Responses.

PubMed

Shin, Hee Soon; Shon, Dong-Hwa

2015-01-01

An immune hypersensitivity disorder called allergy is caused by diverse allergens entering the body via skin contact, injection, ingestion, and/or inhalation. These allergic responses may develop into allergic disorders, including inflammations such as atopic dermatitis, asthma, anaphylaxis, food allergies, and allergic rhinitis. Several drugs have been developed to treat these allergic disorders; however, long-term intake of these drugs could have adverse effects. As an alternative to these medicines, food and natural materials that ameliorate allergic disorder symptoms without producing any side effects can be consumed. Food and natural materials can effectively regulate successive allergic responses in an allergic chain-reaction mechanism in the following ways: [1] Inhibition of allergen permeation via paracellular diffusion into epithelial cells, [2] suppression of type 2 T-helper (Th) cell-related cytokine production by regulating Th1/Th2 balance, [3] inhibition of pathogenic effector CD4(+) T cell differentiation by inducing regulatory T cells (Treg), and [4] inhibition of degranulation in mast cells. The immunomodulatory effects of food and natural materials on each target mechanism were scientifically verified and shown to alleviate allergic disorder symptoms. Furthermore, consumption of certain food and natural materials such as fenugreek, skullcap, chitin/chitosan, and cheonggukjang as anti-allergics have merits such as safety (no adverse side effects), multiple suppressive effects (as a mixture would contain various components that are active against allergic responses), and ease of consumption when required. These merits and anti-allergic properties of food and natural materials help control various allergic disorders.

Inflammasome and Fas-Mediated IL-1β Contributes to Th17/Th1 Cell Induction in Pathogenic Bacterial Infection In Vivo.

PubMed

Uchiyama, Ryosuke; Yonehara, Shin; Taniguchi, Shun'ichiro; Ishido, Satoshi; Ishii, Ken J; Tsutsui, Hiroko

2017-08-01

CD4 + Th cells play crucial roles in orchestrating immune responses against pathogenic microbes, after differentiating into effector subsets. Recent research has revealed the importance of IFN-γ and IL-17 double-producing CD4 + Th cells, termed Th17/Th1 cells, in the induction of autoimmune and inflammatory diseases. In addition, Th17/Th1 cells are involved in the regulation of infection caused by the intracellular bacterium Mycobacterium tuberculosis in humans. However, the precise mechanism of Th17/Th1 induction during pathogen infection is unclear. In this study, we showed that the inflammasome and Fas-dependent IL-1β induces Th17/Th1 cells in mice, in response to infection with the pathogenic intracellular bacterium Listeria monocytogenes In the spleens of infected wild-type mice, Th17/Th1 cells were induced, and expressed T-bet and Rorγt. In Pycard -/- mice, which lack the adaptor molecule of the inflammasome (apoptosis-associated speck-like protein containing a caspase recruitment domain), Th17/Th1 induction was abolished. In addition, the Fas-mediated IL-1β production was required for Th17/Th1 induction during bacterial infection: Th17/Th1 induction was abolished in Fas -/- mice, whereas supplementation with recombinant IL-1β restored Th17/Th1 induction via IL-1 receptor 1 (IL-1R1), and rescued the mortality of Fas -/- mice infected with Listeria IL-1R1, but not apoptosis-associated speck-like protein containing a caspase recruitment domain or Fas on T cells, was required for Th17/Th1 induction, indicating that IL-1β stimulates IL-1R1 on T cells for Th17/Th1 induction. These results indicate that IL-1β, produced by the inflammasome and Fas-dependent mechanisms, contributes cooperatively to the Th17/Th1 induction during bacterial infection. This study provides a deeper understanding of the molecular mechanisms underlying Th17/Th1 induction during pathogenic microbial infections in vivo. Copyright © 2017 by The American Association of Immunologists, Inc.

1alpha,25-dihydroxyvitamin D3 potentiates the beneficial effects of allergen immunotherapy in a mouse model of allergic asthma: role for IL-10 and TGF-beta.

PubMed

Taher, Yousef A; van Esch, Betty C A M; Hofman, Gerard A; Henricks, Paul A J; van Oosterhout, Antoon J M

2008-04-15

1alpha,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), a potent inhibitor of NF-kappaB expression, can prevent the maturation of dendritic cells in vitro leading to tolerogenic dendritic cells with increased potential to induce regulatory T cells. Herein, we investigated whether the combination of allergen immunotherapy with 1,25(OH)(2)D(3) potentiates the suppressive effects of immunotherapy and whether the immunoregulatory cytokines IL-10 and TGF-beta are involved in the effector phase. OVA-sensitized and challenged BALB/c mice displayed airway hyperresponsiveness (AHR) and increased serum OVA-specific IgE levels, bronchoalveolar lavage eosinophilia, and Th2 cytokine levels. In this model, the dose response of allergen immunotherapy 10 days before OVA inhalation challenge shows strong suppression of asthma manifestations at 1 mg of OVA, but partial suppression of bronchoalveolar lavage eosinophilia, IgE up-regulation, and no reduction of AHR at 100 microg. Interestingly, coadministration of 10 ng of 1,25(OH)(2)D(3) with 100 microg of OVA immunotherapy significantly inhibited AHR and potentiated the reduction of serum OVA-specific IgE levels, airway eosinophilia, and Th2-related cytokines concomitant with increased IL-10 levels in lung tissues and TGF-beta and OVA-specific IgA levels in serum. Similar effects on suboptimal immunotherapy were observed by inhibition of the NF-kappaB pathway using the selective IkappaB kinase 2 inhibitor PS-1145. The suppressive effects of this combined immunotherapy were partially reversed by treatment with mAb to either IL-10R or TGF-beta before OVA inhalation challenge but completely abrogated when both Abs were given. These data demonstrate that 1,25(OH)(2)D(3) potentiates the efficacy of immunotherapy and that the regulatory cytokines IL-10 and TGF-beta play a crucial role in the effector phase of this mouse model.

Immunomodulatory Properties of Induced Pluripotent Stem Cell-Derived Mesenchymal Cells.

PubMed

Ng, Jia; Hynes, Kim; White, Gregory; Sivanathan, Kisha Nandini; Vandyke, Kate; Bartold, Peter Mark; Gronthos, Stan

2016-12-01

MSC-like populations derived from induced pluripotent stem cells (iPSC-MSC) serve as an alternative stem cell source due to their high proliferative capacity. In this study, we assessed the immunomodulatory potential of iPSC-MSC generated from periodontal ligament (PDL) and gingival (GF) tissue. The iPSC-MSC lines exhibited a similar level of suppression of mitogen-stimulated peripheral blood mononuclear cells (PBMNC) proliferation compared to their respective parental fibroblast populations in vitro. Moreover, iPSC-MSC demonstrated the ability to suppress T-cells effector cells, Th1/Th2/Th17 populations, and increase levels of Treg cells. In order to investigate the mechanisms involved, expression of common MSC-derived soluble factors known to supress lymphocyte proliferation were assessed in iPSC-MSC cultured with PBMNC with direct cell-cell contact or separated in transwells. Real-time PCR analysis of factors known to be involved in MSC mediated immune regulation, found a general trend of elevated IDO1 and IL6 transcript levels in iPSC-MSC lines and their respective primary cells co-cultured with activated PBMNC, with a wide range of gene expression levels between the different mesenchymal cell types. The results suggest that different iPSC-MSC may be useful as a potential alternative source of cells for future clinical use in therapeutic applications because of their potent immunosuppressive properties. J. Cell. Biochem. 117: 2844-2853, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Differentiation and Transmigration of CD4 T Cells in Neuroinflammation and Autoimmunity.

PubMed

Sonar, Sandip Ashok; Lal, Girdhari

2017-01-01

CD4 + T cells play a central role in orchestrating protective immunity and autoimmunity. The activation and differentiation of myelin-reactive CD4 + T cells into effector (Th1 and Th17) and regulatory (Tregs) subsets at the peripheral tissues, and their subsequent transmigration across the blood-brain barrier (BBB) into the central nervous system (CNS) parenchyma are decisive events in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis. How the Th1, Th17, and regulatory Tregs transmigrate across the BBB into the CNS and cause CNS inflammation is not clearly understood. Studies with transgenic and gene knockout mice have unraveled that Th1, Th17, and Tregs play a critical role in the induction and resolution of neuroinflammation. However, the plasticity of these lineages and functional dichotomy of their cytokine products makes it difficult to understand what role CD4 + T cells in the peripheral lymphoid organs, endothelial BBB, and the CNS parenchyma play in the CNS autoimmune response. In this review, we describe some of the recent findings that shed light on the mechanisms behind the differentiation and transmigration of CD4 + T cells across the BBB into the CNS parenchyma and also highlight how these two processes are interconnected, which is crucial for the outcome of CNS inflammation and autoimmunity.

Differentiation and Transmigration of CD4 T Cells in Neuroinflammation and Autoimmunity

PubMed Central

Sonar, Sandip Ashok; Lal, Girdhari

2017-01-01

CD4+ T cells play a central role in orchestrating protective immunity and autoimmunity. The activation and differentiation of myelin-reactive CD4+ T cells into effector (Th1 and Th17) and regulatory (Tregs) subsets at the peripheral tissues, and their subsequent transmigration across the blood–brain barrier (BBB) into the central nervous system (CNS) parenchyma are decisive events in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis. How the Th1, Th17, and regulatory Tregs transmigrate across the BBB into the CNS and cause CNS inflammation is not clearly understood. Studies with transgenic and gene knockout mice have unraveled that Th1, Th17, and Tregs play a critical role in the induction and resolution of neuroinflammation. However, the plasticity of these lineages and functional dichotomy of their cytokine products makes it difficult to understand what role CD4+ T cells in the peripheral lymphoid organs, endothelial BBB, and the CNS parenchyma play in the CNS autoimmune response. In this review, we describe some of the recent findings that shed light on the mechanisms behind the differentiation and transmigration of CD4+ T cells across the BBB into the CNS parenchyma and also highlight how these two processes are interconnected, which is crucial for the outcome of CNS inflammation and autoimmunity. PMID:29238350

Th22 cells are associated with hepatocellular carcinoma development and progression

PubMed Central

Qin, Shanyu; Ma, Shijia; Huang, Xiaoli; Lu, Donghong

2014-01-01

Objective IL-22-producing CD4+ T helper cells (Th22 cells) have been identified as major inducers of tissue inflammation and immune responses. Currently, no previous study explored the role of Th22 cells in the pathogenesis of hepatocellular carcinoma (HCC). The study aimed to determine the biological function of Th22 cells and its effector IL-22 in HCC patients. Methods Forty-five HCC patients and 19 healthy controls were recruited and their peripheral blood was collected. The fresh HCC tissues, adjacent HCC tissues and ten normal liver tissues were also collected. Flow cytometry analysis was used to determine the frequencies of circulating Th22 cells and Th17 cells. Serum IL-22 levels were tested by enzyme-linked immunosorbent assay (ELISA). Immunohistochemical staining and real-time polymerase chain reaction (PCR) were used to detect IL-22 protein and mRNA in tissues specimens, respectively. Results Circulating Th22 cells, Th17 cells and serum IL-22 levels were significantly elevated in HCC patients compared with those of healthy controls (P<0.001). Th22 cells were showed to be positively correlated with IL-22 in HCC patients (P<0.05), but not in healthy controls. No significant differences were found in HCC patients with HBeAg positivity or negativity in term of Th22 cells and serum IL-22 levels. The expression of IL-22 protein and mRNA was highest in HCC tissues, followed by adjacent HCC tissues and normal liver tissues. Furthermore, Th22 cells, serum IL-22 levels and IL-22 mRNA were elevated at stage III-IV compared with stage I-II of HCC (P<0.05). Conclusions Elevation of circulating Th22 cells and IL-22 may be implicated in the pathogenesis of HCC, and potentially be cellular targets for therapeutic intervention. PMID:24826053

Screening the Budding Yeast Genome Reveals Unique Factors Affecting K2 Toxin Susceptibility

PubMed Central

Servienė, Elena; Lukša, Juliana; Orentaitė, Irma

2012-01-01

Background Understanding how biotoxins kill cells is of prime importance in biomedicine and the food industry. The budding yeast (S. cerevisiae) killers serve as a convenient model to study the activity of biotoxins consistently supplying with significant insights into the basic mechanisms of virus-host cell interactions and toxin entry into eukaryotic target cells. K1 and K2 toxins are active at the cell wall, leading to the disruption of the plasma membrane and subsequent cell death by ion leakage. K28 toxin is active in the cell nucleus, blocking DNA synthesis and cell cycle progression, thereby triggering apoptosis. Genome-wide screens in the budding yeast S. cerevisiae identified several hundred effectors of K1 and K28 toxins. Surprisingly, no such screen had been performed for K2 toxin, the most frequent killer toxin among industrial budding yeasts. Principal Findings We conducted several concurrent genome-wide screens in S. cerevisiae and identified 332 novel K2 toxin effectors. The effectors involved in K2 resistance and hypersensitivity largely map in distinct cellular pathways, including cell wall and plasma membrane structure/biogenesis and mitochondrial function for K2 resistance, and cell wall stress signaling and ion/pH homeostasis for K2 hypersensitivity. 70% of K2 effectors are different from those involved in K1 or K28 susceptibility. Significance Our work demonstrates that despite the fact that K1 and K2 toxins share some aspects of their killing strategies, they largely rely on different sets of effectors. Since the vast majority of the host factors identified here is exclusively active towards K2, we conclude that cells have acquired a specific K2 toxin effectors set. Our work thus indicates that K1 and K2 have elaborated different biological pathways and provides a first step towards the detailed characterization of K2 mode of action. PMID:23227207

Screening the budding yeast genome reveals unique factors affecting K2 toxin susceptibility.

PubMed

Servienė, Elena; Lukša, Juliana; Orentaitė, Irma; Lafontaine, Denis L J; Urbonavičius, Jaunius

2012-01-01

Understanding how biotoxins kill cells is of prime importance in biomedicine and the food industry. The budding yeast (S. cerevisiae) killers serve as a convenient model to study the activity of biotoxins consistently supplying with significant insights into the basic mechanisms of virus-host cell interactions and toxin entry into eukaryotic target cells. K1 and K2 toxins are active at the cell wall, leading to the disruption of the plasma membrane and subsequent cell death by ion leakage. K28 toxin is active in the cell nucleus, blocking DNA synthesis and cell cycle progression, thereby triggering apoptosis. Genome-wide screens in the budding yeast S. cerevisiae identified several hundred effectors of K1 and K28 toxins. Surprisingly, no such screen had been performed for K2 toxin, the most frequent killer toxin among industrial budding yeasts. We conducted several concurrent genome-wide screens in S. cerevisiae and identified 332 novel K2 toxin effectors. The effectors involved in K2 resistance and hypersensitivity largely map in distinct cellular pathways, including cell wall and plasma membrane structure/biogenesis and mitochondrial function for K2 resistance, and cell wall stress signaling and ion/pH homeostasis for K2 hypersensitivity. 70% of K2 effectors are different from those involved in K1 or K28 susceptibility. Our work demonstrates that despite the fact that K1 and K2 toxins share some aspects of their killing strategies, they largely rely on different sets of effectors. Since the vast majority of the host factors identified here is exclusively active towards K2, we conclude that cells have acquired a specific K2 toxin effectors set. Our work thus indicates that K1 and K2 have elaborated different biological pathways and provides a first step towards the detailed characterization of K2 mode of action.

The Role of PKC-θ in CD4+ T Cells and HIV Infection: To the Nucleus and Back Again

PubMed Central

Phetsouphanh, Chansavath; Kelleher, Anthony D.

2015-01-01

Protein kinase C (PKC)-θ is the only member of the PKC family that has the ability to translocate to the immunological synapse between T cells and antigen-presenting cells upon T cell receptor and MHC-II recognition. PKC-θ interacts functionally and physically with other downstream effector molecules to mediate T cell activation, differentiation, and migration. It plays a critical role in the generation of Th2 and Th17 responses and is less important in Th1 and CTL responses. PKC-θ has been recently shown to play a role in the nucleus, where it mediates inducible gene expression in the development of memory CD4+ T cells. This novel PKC (nPKC) can up-regulate HIV-1 transcription and PKC-θ activators such as Prostratin have been used in early HIV-1 reservoir eradication studies. The exact manner of the activation of virus by these compounds and the role of PKC-θ, particularly its nuclear form and its association with NF-κB in both the cytoplasmic and nuclear compartments, needs further precise elucidation especially given the very important role of NF-κB in regulating transcription from the integrated retrovirus. Continued studies of this nPKC isoform will give further insight into the complexity of T cell signaling kinases. PMID:26284074

MHC class II/ESO tetramer-based generation of in vitro primed anti-tumor T-helper lines for adoptive cell therapy of cancer.

PubMed

Poli, Caroline; Raffin, Caroline; Dojcinovic, Danijel; Luescher, Immanuel; Ayyoub, Maha; Valmori, Danila

2013-02-01

Generation of tumor-antigen specific CD4(+) T-helper (T(H)) lines through in vitro priming is of interest for adoptive cell therapy of cancer, but the development of this approach has been limited by the lack of appropriate tools to identify and isolate low frequency tumor antigen-specific CD4(+) T cells. Here, we have used recently developed MHC class II/peptide tetramers incorporating an immunodominant peptide from NY-ESO-1 (ESO), a tumor antigen frequently expressed in different human solid and hematologic cancers, to implement an in vitro priming platform allowing the generation of ESO-specific T(H) lines. We isolated phenotypically defined CD4(+) T-cell subpopulations from circulating lymphocytes of DR52b(+) healthy donors by flow cytometry cell sorting and stimulated them in vitro with peptide ESO(119-143), autologous APC and IL-2. We assessed the frequency of ESO-specific cells in the cultures by staining with DR52b/ESO(119-143) tetramers (ESO-tetramers) and TCR repertoire of ESO-tetramer(+) cells by co-staining with TCR variable β chain (BV) specific antibodies. We isolated ESO-tetramer(+) cells by flow cytometry cell sorting and expanded them with PHA, APC and IL-2 to generate ESO-specific T(H) lines. We characterized the lines for antigen recognition, by stimulation with ESO peptide or recombinant protein, cytokine production, by intracellular staining using specific antibodies, and alloreactivity, by stimulation with allo-APC. Using this approach, we could consistently generate ESO-tetramer(+) T(H) lines from conventional CD4(+)CD25(-) naïve and central memory populations, but not from effector memory populations or CD4(+)CD25(+) Treg. In vitro primed T(H) lines recognized ESO with affinities comparable to ESO-tetramer(+) cells from patients immunized with an ESO vaccine and used a similar TCR repertoire. In this study, using MHC class II/ESO tetramers, we have implemented an in vitro priming platform allowing the generation of ESO-monospecific polyclonal T(H) lines from non-immune individuals. This is an approach that is of potential interest for adoptive cell therapy of patients bearing ESO-expressing cancers.

CD134/CD137 Dual Costimulation-Elicited IFN-γ Maximizes Effector T Cell Function but Limits Treg Expansion

PubMed Central

Rose, Marie-Clare St.; Taylor, Roslyn A.; Bandyopadhyay, Suman; Qui, Harry Z.; Hagymasi, Adam T.; Vella, Anthony T.; Adler, Adam J.

2012-01-01

T cell tolerance to tumor antigens represents a major hurdle in generating tumor immunity. Combined administration of agonistic monoclonal antibodies to the costimulatory receptors CD134 plus CD137 can program T cells responding to tolerogenic antigen to undergo expansion and effector T cell differentiation, and also elicits tumor immunity. Nevertheless, CD134 and CD137 agonists can also engage inhibitory immune components. To understand how immune stimulatory versus inhibitory components are regulated during CD134 plus CD137 dual costimulation, the current study utilized a model where dual costimulation programs T cells encountering a highly tolerogenic self-antigen to undergo effector differentiation. IFN-γ was found to play a pivotal role in maximizing the function of effector T cells while simultaneously limiting the expansion of CD4+CD25+Foxp3+ Tregs. In antigen-responding effector T cells, IFN-γ operates via a direct cell-intrinsic mechanism to cooperate with IL-2 to program maximal expression of granzyme B. Simultaneously, IFN-γ limits expression of the IL-2 receptor alpha chain (CD25) and IL-2 signaling through a mechanism that does not involve T-bet-mediated repression of IL-2. IFN-γ also limited CD25 and Foxp3 expression on bystanding CD4+Foxp3+ Tregs, and limited the potential of these Tregs to expand. These effects could not be explained by the ability of IFN-γ to limit IL-2 availability. Taken together, during dual costimulation IFN-γ interacts with IL-2 through distinct mechanisms to program maximal expression of effector molecules in antigen-responding T cells while simultaneously limiting Treg expansion. PMID:23295363

Functional reprogramming of human prostate cancer to promote local attraction of effector CD8(+) T cells.

PubMed

Muthuswamy, Ravikumar; Corman, John M; Dahl, Kathryn; Chatta, Gurkamal S; Kalinski, Pawel

2016-09-01

Local infiltration of CD8(+) T cells (CTLs) in tumor lesions predicts overall clinical outcomes and the clinical benefit of cancer patients from immune checkpoint blockade. In the current study, we evaluated local production of different classes of chemokines in prostate cancer lesions, and the feasibility of their modulation to promote selective entry of CTLs into prostate tumors. Chemokine expression in prostate cancer lesion was analyzed by TaqMan-based quantitative PCR, confocal fluorescence microscopy and ELISA. For ex vivo chemokine modulation analysis, prostate tumor explants from patients undergoing primary prostate cancer resections were cultured for 24 hr, in the absence or presence of the combination of poly-I:C, IFNα, and celecoxib (PAC). The numbers of cells producing defined chemokines in the tissues were analyzed by confocal microscopy. Chemotaxis of effector CD8(+) T cells towards the untreated and PAC-treated tumor explant supernatants were evaluated in a standard in vitro migration assays, using 24 well trans-well plates. The number of effector cells that migrated was enumerated by flow cytometry. Pearson (r) correlation was used for analyzing correlations between chemokines and immune filtrate, while paired two tailed students t-test was used for comparison between treatment groups. Prostate tumors showed uniformly low levels of CTL/NK/Th1-recruiting chemokines (CCL5, CXCL9, CXCL10) but expressed high levels of chemokines implicated in the attraction of myeloid derived suppressor cells (MDSC) and regulatory T cells (Treg ): CCL2, CCL22, and CXCL12. Strong positive correlations were observed between CXCL9 and CXCL10 and local CD8 expression. Tumor expression levels of CCL2, CCL22, and CXCL12 were correlated with intratumoral expression of MDSC/Treg markers: FOXP3, CD33, and NCF2. Treatment with PAC suppressed intratumoral production of the Treg -attractant CCL22 and Treg /MDSC-attractant, CXCL12, while increasing the production of the CTL attractant, CXCL10. These changes in local chemokine production were accompanied by the reduced ability of the ex vivo-treated tumors to attract CD4(+) FOXP3(+) Treg cells, and strongly enhanced attraction of the CD8(+) Granzyme B(+) CTLs. Our data demonstrate that the chemokine environment in prostate cancer can be reprogrammed to selectively enhance the attraction of type-1 effector immune cells and reduce local attraction of MDSCs and Tregs . Prostate 76:1095-1105, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Protection by and maintenance of CD4 effector memory and effector T cell subsets in persistent malaria infection.

PubMed

Opata, Michael M; Ibitokou, Samad A; Carpio, Victor H; Marshall, Karis M; Dillon, Brian E; Carl, Jordan C; Wilson, Kyle D; Arcari, Christine M; Stephens, Robin

2018-04-01

Protection at the peak of Plasmodium chabaudi blood-stage malaria infection is provided by CD4 T cells. We have shown that an increase in Th1 cells also correlates with protection during the persistent phase of malaria; however, it is unclear how these T cells are maintained. Persistent malaria infection promotes protection and generates both effector T cells (Teff), and effector memory T cells (Tem). We have previously defined new CD4 Teff (IL-7Rα-) subsets from Early (TeffEarly, CD62LhiCD27+) to Late (TeffLate, CD62LloCD27-) activation states. Here, we tested these effector and memory T cell subsets for their ability to survive and protect in vivo. We found that both polyclonal and P. chabaudi Merozoite Surface Protein-1 (MSP-1)-specific B5 TCR transgenic Tem survive better than Teff. Surprisingly, as Tem are associated with antigen persistence, Tem survive well even after clearance of infection. As previously shown during T cell contraction, TeffEarly, which can generate Tem, also survive better than other Teff subsets in uninfected recipients. Two other Tem survival mechanisms identified here are that low-level chronic infection promotes Tem both by driving their proliferation, and by programming production of Tem from Tcm. Protective CD4 T cell phenotypes have not been precisely determined in malaria, or other persistent infections. Therefore, we tested purified memory (Tmem) and Teff subsets in protection from peak pathology and parasitemia in immunocompromised recipient mice. Strikingly, among Tmem (IL-7Rαhi) subsets, only TemLate (CD62LloCD27-) reduced peak parasitemia (19%), though the dominant memory subset is TemEarly, which is not protective. In contrast, all Teff subsets reduced peak parasitemia by more than half, and mature Teff can generate Tem, though less. In summary, we have elucidated four mechanisms of Tem maintenance, and identified two long-lived T cell subsets (TemLate, TeffEarly) that may represent correlates of protection or a target for longer-lived vaccine-induced protection against malaria blood-stages.

The imbalance between regulatory and IL-17-secreting CD4⁺T cells in multiple-trauma rat.

PubMed

Dai, Heling; Sun, Tiansheng; Liu, Zhi; Zhang, Jianzheng; Zhou, Meng

2013-11-01

It has been well recognised that a deficit of numbers and function of CD4(+)CD25(+)Foxp3(+)cells (Treg) is attributed to the development of auto-immune diseases, inflammatory diseases, tumour and rejection of transplanted tissue; however, there are controversial data regarding the suppressive effect of Treg cells on the T-cell response in auto-immune diseases. Additionally, interleukin-17 (IL-17)-producing cells (Th17) have a pro-inflammatory role. The balance between Th17 and Treg may be essential for maintaining immune homeostasis and has long been thought as one of the important factors in the development/prevention of auto-immune diseases, inflammatory diseases, tumour and rejection of transplanted tissue, but their role in multiple trauma remains unclear. This study aims to investigate whether an imbalance of Treg and Th17 effector cells is characteristic of rats suffering from multiple trauma. Sixty Sprague-Dawley (SD) rats were randomly divided into three groups. The control group (n=20, group I) no received procedures (normal). The sham group (n=20, group II) only received anaesthesia, cannulation and observation. The bilateral femoral shaft fractures with haemorrhagic shock groups (n=20, group III). Rats in groups II and III were killed at the end of 4h after models were established. Peripheral blood samples were collected for assessment of Treg cells, Th17 cells and cytokines (IL-17, IL-6, IL-2, transforming growth factor beta (TGF-β)) and intestine tissue was collected for intestine histological analysis. We observed decreased Treg/Th17 ratios in CD4(+)T cells in rats with multiple trauma and a strong inverse correlation with disease activity (intestinal histological scores). We suggest a role for immune imbalance in the pathogenesis and development of multiple trauma. The alteration of the index of Treg/Th17 cells likely indicates the therapeutic response and progress in the clinic. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Mannosylated Mucin-Type Immunoglobulin Fusion Proteins Enhance Antigen-Specific Antibody and T Lymphocyte Responses

PubMed Central

Johansson, Tomas; Nilsson, Anki; Chatzissavidou, Nathalie; Sjöblom, Magnus; Rova, Ulrika; Holgersson, Jan

2012-01-01

Targeting antigens to antigen-presenting cells (APC) improve their immunogenicity and capacity to induce Th1 responses and cytotoxic T lymphocytes (CTL). We have generated a mucin-type immunoglobulin fusion protein (PSGL-1/mIgG2b), which upon expression in the yeast Pichia pastoris became multivalently substituted with O-linked oligomannose structures and bound the macrophage mannose receptor (MMR) and dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN) with high affinity in vitro. Here, its effects on the humoral and cellular anti-ovalbumin (OVA) responses in C57BL/6 mice are presented. OVA antibody class and subclass responses were determined by ELISA, the generation of anti-OVA CTLs was assessed in 51Cr release assays using in vitro-stimulated immune spleen cells from the different groups of mice as effector cells and OVA peptide-fed RMA-S cells as targets, and evaluation of the type of Th cell response was done by IFN-γ, IL-2, IL-4 and IL-5 ELISpot assays. Immunizations with the OVA − mannosylated PSGL-1/mIgG2b conjugate, especially when combined with the AbISCO®-100 adjuvant, lead to faster, stronger and broader (with regard to IgG subclass) OVA IgG responses, a stronger OVA-specific CTL response and stronger Th1 and Th2 responses than if OVA was used alone or together with AbISCO®-100. Also non-covalent mixing of mannosylated PSGL-1/mIgG2b, OVA and AbISCO®-100 lead to relatively stronger humoral and cellular responses. The O-glycan oligomannoses were necessary because PSGL-1/mIgG2b with mono- and disialyl core 1 structures did not have this effect. Mannosylated mucin-type fusion proteins can be used as versatile APC-targeting molecules for vaccines and as such enhance both humoral and cellular immune responses. PMID:23071675

Modulatory effects of vitamin D on peripheral cellular immunity in patients with recurrent miscarriage.

PubMed

Chen, Xian; Yin, Biao; Lian, Ruo-Chun; Zhang, Tao; Zhang, Hong-Zhan; Diao, Liang-Hui; Li, Yu-Ye; Huang, Chun-Yu; Liang, De-Sheng; Zeng, Yong

2016-12-01

We aimed to investigate the modulatory effects of vitamin D on peripheral blood cellular immune response in patients with recurrent miscarriage (RM). The effect of vitamin D on the number of peripheral blood cells, T helper 1 (Th1) cytokines, and NK cytotoxicity was measured in 99 women with RM. The percentage of CD19 + B cells and NK cytotoxicity at an effector-to-target cell (E:T) ratio of 50:1, 25:1, and 12.5:1 were significantly higher in the vitamin D insufficiency group (VDI) than in the vitamin D normal group (VDN) (P<.05 each). The proportion of TNF-α-expressing Th cells was significantly higher in the vitamin D deficiency group (VDD) than in VDN (P<.05). However, there were no significant differences between VDI and VDD. This dysregulation was significantly reduced with 1,25(OH) 2 D supplementation. The data suggest that the abnormalities of cellular immune response were observed in RM patients with a low vitamin D level, which could be regulated to some extent with 1,25(OH) 2 D supplementation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A novel role for autologous tumour cell vaccination in the immunotherapy of the poorly immunogenic B16-BL6 melanoma.

PubMed

Geiger, J D; Wagner, P D; Shu, S; Chang, A E

1992-06-01

The growth of immunogenic tumours stimulates the generation of tumour-sensitized, but not functional, pre-effector T cells in the draining lymph nodes. These pre-effector cells can mature into effector cells upon in-vitro stimulation with anti-CD3 and IL-2. In the current study, using a defined, poorly immunogenic tumour, B16-BL6 melanoma, the pre-effector cell response was not evident during progressive tumour growth but was elicited by vaccination with irradiated tumour cells admixed with Corynebacterium parvum. After anti-CD3/IL-2 activation, these cells were capable of mediating the regression of established pulmonary metastases. The efficacy of the vaccine depended on the doses of both tumour cells and the adjuvant. While higher numbers of tumour cells were more effective, an optimal dose (12.5 micrograms) of C. parvum was required. The dose of irradiation was not a critical factor. After vaccination, kinetic studies revealed that the pre-effector cell response was evident 4 days later and declined after 14 days. These observations illustrate the potential role of active immunization in the cellular therapy of cancer.

Bacterial effector HopF2 interacts with AvrPto and suppresses Arabidopsis innate immunity at the plasma membrane

USDA-ARS?s Scientific Manuscript database

Plant pathogenic bacteria inject a cocktail of effector proteins into host plant cells to modulate the host immune response, thereby promoting pathogenicity. How or whether these effectors work cooperatively is largely unknown. The Pseudomonas syringae DC3000 effector HopF2 suppresses the host plan...

Deciphering Interplay between Salmonella Invasion Effectors

PubMed Central

Koronakis, Vassilis

2008-01-01

Bacterial pathogens have evolved a specialized type III secretion system (T3SS) to translocate virulence effector proteins directly into eukaryotic target cells. Salmonellae deploy effectors that trigger localized actin reorganization to force their own entry into non-phagocytic host cells. Six effectors (SipC, SipA, SopE/2, SopB, SptP) can individually manipulate actin dynamics at the plasma membrane, which acts as a ‘signaling hub’ during Salmonella invasion. The extent of crosstalk between these spatially coincident effectors remains unknown. Here we describe trans and cis binary entry effector interplay (BENEFIT) screens that systematically examine functional associations between effectors following their delivery into the host cell. The results reveal extensive ordered synergistic and antagonistic relationships and their relative potency, and illuminate an unexpectedly sophisticated signaling network evolved through longstanding pathogen–host interaction. PMID:18389058

Demonstration of NK cell-mediated lysis of varicella-zoster virus (VZV)-infected cells: characterization of the effector cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tilden, A.B.; Cauda, R.; Grossi, C.E.

1986-06-01

Infection with varicella-zoster virus (VZV) rendered RAJI cells more susceptible to lysis by non-adherent blood lymphocytes. At an effector to target ratio of 80:1 the mean percentage of /sup 51/Cr release of VZV-infected RAJI cells was 41 +/- 12%, whereas that of uninfected RAJI cells was 15 +/- 6%. The increased susceptibility to lysis was associated with increased effector to target conjugate formation in immunofluorescence binding assays. The effector cells cytotoxic for VZV-infected RAJI cells were predominantly Leu-11a/sup +/ Leu-4/sup -/ granular lymphocytes as demonstrated by fluorescence-activated cell sorting. The effector cell active against VZV-infected RAJI cells appeared similar tomore » those active against herpes simplex virus (HSV)-infected cells, because in cold target competition experiments the lysis of /sup 51/Cr-labeled VZV-infected RAJI cells was efficiently inhibited by either unlabeled VZV-infected RAJI cells (mean 71% inhibition, 2:1 ratio unlabeled to labeled target) or HSV-infected RAJI cells (mean 69% inhibition) but not by uninfected RAJI cells (mean 10% inhibition). In contrast, competition experiments revealed donor heterogeneity in the overlap between effector cells for VZV- or HSV-infected RAJI vs K-562 cells.« less

Yellow fever vaccination elicits broad functional CD4+ T cell responses that recognize structural and nonstructural proteins.

PubMed

James, Eddie A; LaFond, Rebecca E; Gates, Theresa J; Mai, Duy T; Malhotra, Uma; Kwok, William W

2013-12-01

Yellow fever virus (YFV) can induce acute, life-threatening disease that is a significant health burden in areas where yellow fever is endemic, but it is preventable through vaccination. The live attenuated 17D YFV strain induces responses characterized by neutralizing antibodies and strong T cell responses. This vaccine provides an excellent model for studying human immunity. While several studies have characterized YFV-specific antibody and CD8(+) T cell responses, less is known about YFV-specific CD4(+) T cells. Here we characterize the epitope specificity, functional attributes, and dynamics of YFV-specific T cell responses in vaccinated subjects by investigating peripheral blood mononuclear cells by using HLA-DR tetramers. A total of 112 epitopes restricted by seven common HLA-DRB1 alleles were identified. Epitopes were present within all YFV proteins, but the capsid, envelope, NS2a, and NS3 proteins had the highest epitope density. Antibody blocking demonstrated that the majority of YFV-specific T cells were HLA-DR restricted. Therefore, CD4(+) T cell responses could be effectively characterized with HLA-DR tetramers. Ex vivo tetramer analysis revealed that YFV-specific T cells persisted at frequencies ranging from 0 to 100 cells per million that are detectable years after vaccination. Longitudinal analysis indicated that YFV-specific CD4(+) T cells reached peak frequencies, often exceeding 250 cells per million, approximately 2 weeks after vaccination. As frequencies subsequently declined, YFV-specific cells regained CCR7 expression, indicating a shift from effector to central memory. Cells were typically CXCR3 positive, suggesting Th1 polarization, and produced gamma interferon and other cytokines after reactivation in vitro. Therefore, YFV elicits robust early effector CD4(+) T cell responses that contract, forming a detectable memory population.

Yellow Fever Vaccination Elicits Broad Functional CD4+ T Cell Responses That Recognize Structural and Nonstructural Proteins

PubMed Central

James, Eddie A.; LaFond, Rebecca E.; Gates, Theresa J.; Mai, Duy T.; Malhotra, Uma

2013-01-01

Yellow fever virus (YFV) can induce acute, life-threatening disease that is a significant health burden in areas where yellow fever is endemic, but it is preventable through vaccination. The live attenuated 17D YFV strain induces responses characterized by neutralizing antibodies and strong T cell responses. This vaccine provides an excellent model for studying human immunity. While several studies have characterized YFV-specific antibody and CD8+ T cell responses, less is known about YFV-specific CD4+ T cells. Here we characterize the epitope specificity, functional attributes, and dynamics of YFV-specific T cell responses in vaccinated subjects by investigating peripheral blood mononuclear cells by using HLA-DR tetramers. A total of 112 epitopes restricted by seven common HLA-DRB1 alleles were identified. Epitopes were present within all YFV proteins, but the capsid, envelope, NS2a, and NS3 proteins had the highest epitope density. Antibody blocking demonstrated that the majority of YFV-specific T cells were HLA-DR restricted. Therefore, CD4+ T cell responses could be effectively characterized with HLA-DR tetramers. Ex vivo tetramer analysis revealed that YFV-specific T cells persisted at frequencies ranging from 0 to 100 cells per million that are detectable years after vaccination. Longitudinal analysis indicated that YFV-specific CD4+ T cells reached peak frequencies, often exceeding 250 cells per million, approximately 2 weeks after vaccination. As frequencies subsequently declined, YFV-specific cells regained CCR7 expression, indicating a shift from effector to central memory. Cells were typically CXCR3 positive, suggesting Th1 polarization, and produced gamma interferon and other cytokines after reactivation in vitro. Therefore, YFV elicits robust early effector CD4+ T cell responses that contract, forming a detectable memory population. PMID:24049183

Protecting and rescuing the effectors: roles of differentiation and survival in the control of memory T cell development

PubMed Central

Kurtulus, Sema; Tripathi, Pulak; Hildeman, David A.

2013-01-01

Vaccines, arguably the single most important intervention in improving human health, have exploited the phenomenon of immunological memory. The elicitation of memory T cells is often an essential part of successful long-lived protective immunity. Our understanding of T cell memory has been greatly aided by the development of TCR Tg mice and MHC tetrameric staining reagents that have allowed the precise tracking of antigen-specific T cell responses. Indeed, following acute infection or immunization, naïve T cells undergo a massive expansion culminating in the generation of a robust effector T cell population. This peak effector response is relatively short-lived and, while most effector T cells die by apoptosis, some remain and develop into memory cells. Although the molecular mechanisms underlying this cell fate decision remain incompletely defined, substantial progress has been made, particularly with regards to CD8+ T cells. For example, the effector CD8+ T cells generated during a response are heterogeneous, consisting of cells with more or less potential to develop into full-fledged memory cells. Development of CD8+ T cell memory is regulated by the transcriptional programs that control the differentiation and survival of effector T cells. While the type of antigenic stimulation and level of inflammation control effector CD8+ T cell differentiation, availability of cytokines and their ability to control expression and function of Bcl-2 family members governs their survival. These distinct differentiation and survival programs may allow for finer therapeutic intervention to control both the quality and quantity of CD8+ T cell memory. Effector to memory transition of CD4+ T cells is less well characterized than CD8+ T cells, emerging details will be discussed. This review will focus on the recent progress made in our understanding of the mechanisms underlying the development of T cell memory with an emphasis on factors controlling survival of effector T cells. PMID:23346085

Host protective roles of type 2 immunity: Parasite killing and tissue repair, flip sides of the same coin

PubMed Central

Allen, Judith E.; Sutherland, Tara E.

2014-01-01

Metazoan parasites typically induce a type 2 immune response, characterized by T helper 2 (Th2) cells that produce the cytokines IL-4, IL-5 and IL-13 among others. The type 2 response is host protective, reducing the number of parasites either through direct killing in the tissues, or expulsion from the intestine. Type 2 immunity also protects the host against damage mediated by these large extracellular parasites as they migrate through the body. At the center of both the innate and adaptive type 2 immune response, is the IL-4Rα that mediates many of the key effector functions. Here we highlight the striking overlap between the molecules, cells and pathways that mediate both parasite control and tissue repair. We have proposed that adaptive Th2 immunity evolved out of our innate repair pathways to mediate both accelerated repair and parasite control in the face of continual assault from multicellular pathogens. Type 2 cytokines are involved in many aspects of mammalian physiology independent of helminth infection. Therefore understanding the evolutionary relationship between helminth killing and tissue repair should provide new insight into immune mechanisms of tissue protection in the face of physical injury. PMID:25028340

Chemical Genetics Reveals Bacterial and Host Cell Functions Critical for Type IV Effector Translocation by Legionella pneumophila

PubMed Central

Charpentier, Xavier; Gabay, Joëlle E.; Reyes, Moraima; Zhu, Jing W.; Weiss, Arthur; Shuman, Howard A.

2009-01-01

Delivery of effector proteins is a process widely used by bacterial pathogens to subvert host cell functions and cause disease. Effector delivery is achieved by elaborate injection devices and can often be triggered by environmental stimuli. However, effector export by the L. pneumophila Icm/Dot Type IVB secretion system cannot be detected until the bacterium encounters a target host cell. We used chemical genetics, a perturbation strategy that utilizes small molecule inhibitors, to determine the mechanisms critical for L. pneumophila Icm/Dot activity. From a collection of more than 2,500 annotated molecules we identified specific inhibitors of effector translocation. We found that L. pneumophila effector translocation in macrophages requires host cell factors known to be involved in phagocytosis such as phosphoinositide 3-kinases, actin and tubulin. Moreover, we found that L. pneumophila phagocytosis and effector translocation also specifically require the receptor protein tyrosine phosphate phosphatases CD45 and CD148. We further show that phagocytosis is required to trigger effector delivery unless intimate contact between the bacteria and the host is artificially generated. In addition, real-time analysis of effector translocation suggests that effector export is rate-limited by phagocytosis. We propose a model in which L. pneumophila utilizes phagocytosis to initiate an intimate contact event required for the translocation of pre-synthesized effector molecules. We discuss the need for host cell participation in the initial step of the infection and its implications in the L. pneumophila lifestyle. Chemical genetic screening provides a novel approach to probe the host cell functions and factors involved in host–pathogen interactions. PMID:19578436

An optimized IFN-γ ELISpot assay for the sensitive and standardized monitoring of CMV protein-reactive effector cells of cell-mediated immunity.

PubMed

Barabas, Sascha; Spindler, Theresa; Kiener, Richard; Tonar, Charlotte; Lugner, Tamara; Batzilla, Julia; Bendfeldt, Hanna; Rascle, Anne; Asbach, Benedikt; Wagner, Ralf; Deml, Ludwig

2017-03-07

In healthy individuals, Cytomegalovirus (CMV) infection is efficiently controlled by CMV-specific cell-mediated immunity (CMI). Functional impairment of CMI in immunocompromized individuals however can lead to uncontrolled CMV replication and severe clinical complications. Close monitoring of CMV-specific CMI is therefore clinically relevant and might allow a reliable prognosis of CMV disease as well as assist personalized therapeutic decisions. Objective of this work was the optimization and technical validation of an IFN-γ ELISpot assay for a standardized, sensitive and reliable quantification of CMV-reactive effector cells. T-activated® immunodominant CMV IE-1 and pp65 proteins were used as stimulants. All basic assay parameters and reagents were tested and optimized to establish a user-friendly protocol and maximize the signal-to-noise ratio of the ELISpot assay. Optimized and standardized ELISpot revealed low intra-assay, inter-assay and inter-operator variability (coefficient of variation CV below 22%) and CV inter-site was lower than 40%. Good assay linearity was obtained between 6 × 10 4 and 2 × 10 5 PBMC per well upon stimulation with T-activated® IE-1 (R 2  = 0.97) and pp65 (R 2  = 0.99) antigens. Remarkably, stimulation of peripheral blood mononuclear cells (PBMC) with T-activated® IE-1 and pp65 proteins resulted in the activation of a broad range of CMV-reactive effector cells, including CD3 + CD4 + (Th), CD3 + CD8 + (CTL), CD3 - CD56 + (NK) and CD3 + CD56 + (NKT-like) cells. Accordingly, the optimized IFN-γ ELISpot assay revealed very high sensitivity (97%) in a cohort of 45 healthy donors, of which 32 were CMV IgG-seropositive. The combined use of T-activated® IE-1 and pp65 proteins for the stimulation of PBMC with the optimized IFN-γ ELISpot assay represents a highly standardized, valuable tool to monitor the functionality of CMV-specific CMI with great sensitivity and reliability.

Protein-Protein Interaction Assays with Effector-GFP Fusions in Nicotiana benthamiana.

PubMed

Petre, Benjamin; Win, Joe; Menke, Frank L H; Kamoun, Sophien

2017-01-01

Plant parasites secrete proteins known as effectors into host tissues to manipulate host cell structures and functions. One of the major goals in effector biology is to determine the host cell compartments and the protein complexes in which effectors accumulate. Here, we describe a five-step pipeline that we routinely use in our lab to achieve this goal, which consists of (1) Golden Gate assembly of pathogen effector-green fluorescent protein (GFP) fusions into binary vectors, (2) Agrobacterium-mediated heterologous protein expression in Nicotiana benthamiana leaf cells, (3) laser-scanning confocal microscopy assay, (4) anti-GFP coimmunoprecipitation-liquid chromatography-tandem mass spectrometry (coIP/MS) assay, and (5) anti-GFP western blotting. This pipeline is suitable for rapid, cost-effective, and medium-throughput screening of pathogen effectors in planta.

[The research on xiaochalhu decoction improving the inflammation of chronic glomerulonephritis patients and relieving the proteinuria].

PubMed

Ding, Shi-Yong; Zheng, Ping-Dong; He, Li-Qun; Hou, Wei-Guo; Zou, Yun; Gao, Jian-Dong

2013-01-01

To observe the balance of T help cell1/2 (Th1/Th2), the changes of correlated proinflammatory cytokines (IFN-gamma and IL-4), and regulated on activation normal T cell expressed and secreted (RANTES), and the abnormal expression of IL-17, the effector of T help cell17 (Th17) in chronic glomerulonephritis (CGN)patients with Shaoyang disease, thus revealing the mechanisms of Xiaochaihu Decoction (XD) for treating proteinuria of CGN patients according to the theory of mediating Shaoyang meridian. Totally 70 CGN patients with Shaoyang disease were randomly assigned to two groups, the treatment group (treated by XD) and the control group [treated by Shenyan Kangfu Tablet (SKT)], 35 in each group. Besides, 20 healthy volunteers were recruited as the healthy control group. Besides, routine therapy of chronic kidney disease (CKD), patients in the treatment group and the control group were treated with XD and SKT respectively for 4 weeks. The changes of Chinese medical syndrome, the effectiveness, 24-h urinary protein, renal functions, the peripheral blood IFN-gamma, IL-4, Th1/Th2, IL-17, and RANTES were compared. Before treatment the Th1/Th2, IL-17, and RANTES of the two treated groups were higher, and the IL-4 level was lower than those of the healthy control group (P < 0.05). After treatment the improvement of Chinese medical syndrome, main symptoms, the effectiveness was better in the XD group than in the SKT group (P < 0.05, P < 0.01). The proteinuria obviously decreased in the treatment group, with the efficacy superior to the SKT group (P < 0.05). The Th1/Th2, IL-17, and RANTES decreased to various degrees when compared with the SKT group (P < 0.05, P < 0.01). The IL-4 level increased more obviously in the treatment group than in the control group (P < 0.05). There was no statistical difference in the improvement of the renal function (P > 0.05). The immune disorder of the CGN patients with Shaoyang disease was correlated with Th1/Th2 imbalance, and abnormal changes of Th17 cell functions and RANTES. XD could improve the inflammation by regulating the immune disorder of CGN patients with Shaoyang disease, which proved that the theory of mediating Shaoyang meridian could be used to improve the inflammation of CGN patients, thus relieving the proteinuria.

Rust fungal effectors mimic host transit peptides to translocate into chloroplasts.

PubMed

Petre, Benjamin; Lorrain, Cécile; Saunders, Diane G O; Win, Joe; Sklenar, Jan; Duplessis, Sébastien; Kamoun, Sophien

2016-04-01

Parasite effector proteins target various host cell compartments to alter host processes and promote infection. How effectors cross membrane-rich interfaces to reach these compartments is a major question in effector biology. Growing evidence suggests that effectors use molecular mimicry to subvert host cell machinery for protein sorting. We recently identified chloroplast-targeted protein 1 (CTP1), a candidate effector from the poplar leaf rust fungus Melampsora larici-populina that carries a predicted transit peptide and accumulates in chloroplasts and mitochondria. Here, we show that the CTP1 transit peptide is necessary and sufficient for accumulation in the stroma of chloroplasts. CTP1 is part of a Melampsora-specific family of polymorphic secreted proteins. Two members of that family, CTP2 and CTP3, also translocate in chloroplasts in an N-terminal signal-dependent manner. CTP1, CTP2 and CTP3 are cleaved when they accumulate in chloroplasts, while they remain intact when they do not translocate into chloroplasts. Our findings reveal that fungi have evolved effector proteins that mimic plant-specific sorting signals to traffic within plant cells. © 2015 John Wiley & Sons Ltd.

OGR1/GPR68 Modulates the Severity of Experimental Autoimmune Encephalomyelitis and Regulates Nitric Oxide Production by Macrophages

PubMed Central

D’Souza, Cheryl A.; Zhao, Fei Linda; Li, Xujian; Xu, Yan; Dunn, Shannon E.; Zhang, Li

2016-01-01

Ovarian cancer G protein-coupled receptor 1 (OGR1) is a proton-sensing molecule that can detect decreases in extracellular pH that occur during inflammation. Although OGR1 has been shown to have pro-inflammatory functions in various diseases, its role in autoimmunity has not been examined. We therefore sought to determine whether OGR1 has a role in the development of T cell autoimmunity by contrasting the development of experimental autoimmune encephalomyelitis between wild type and OGR1-knockout mice. OGR1-knockout mice showed a drastically attenuated clinical course of disease that was associated with a profound reduction in the expansion of myelin oligodendrocyte glycoprotein 35-55-reactive T helper 1 (Th1) and Th17 cells in the periphery and a reduced accumulation of Th1 and Th17 effectors in the central nervous system. We determined that these impaired T cell responses in OGR1-knockout mice associated with a reduced frequency and number of dendritic cells in draining lymph nodes during EAE and a higher production of nitric oxide by macrophages. Our studies suggest that OGR1 plays a key role in regulating T cell responses during autoimmunity. PMID:26828924

Mesenteric Th1 polarization and monocyte TNF-alpha production: first steps to systemic inflammation in rats with cirrhosis.

PubMed

Muñoz, Leticia; Albillos, Agustín; Nieto, Mónica; Reyes, Eduardo; Lledó, Lourdes; Monserrat, Jorge; Sanz, Eva; de la Hera, Antonio; Alvarez-Mon, Melchor

2005-08-01

A systemic inflammatory state with increased circulating tumor necrosis factor alpha (TNF-alpha) has been related to the bacterial infection susceptibility and hemodynamic derangement of patients with cirrhosis. We compared the activation status of immune cell subpopulations defined by 4-color cytometry in mesenteric and peripheral lymph nodes and blood of rats with CCl(4)-cirrhosis to define the immune response initiation site, the T-cell and monocyte contribution to pro-inflammatory cytokine production, as well as the pathogenic role of enteric bacteria in the cirrhosis immune response. Th1 cells and monocytes were expanded in the mesenteric nodes (P < .001) and blood (P < .001) of rats with cirrhosis, and activated to produce interferon gamma (P < .0001) and TNF-alpha (P < .0001), respectively. The greater numbers of recently activated CD134(+) Th cells in mesenteric nodes compared with blood, the correlation between their numbers in mesenteric nodes and blood (r = 0.66, P < .001), and the expansion of activated CD45RC(-) Th cells, which are unable to re-enter lymph nodes, in mesenteric nodes but not in blood or axillary nodes points to mesenteric nodes as the origin site of activated Th cells. Abrogation of bacterial translocation by bowel decontamination reduced the number of activated Th cells and monocytes, and normalized interferon gamma production by Th cells and TNF-alpha production by monocytes in mesenteric nodes and blood, respectively. In conclusion, in cirrhosis, enteric bacteria start off an orchestrated immune response cascade in mesenteric nodes involving Th1 polarization and monocyte activation to TNF-alpha production. Later, the recirculation of these activated effector immune cells into blood promotes systemic inflammation.

Heterogeneity of T Cell Responses to Pandemic pH1N1 Monovalent Vaccine in HIV-Infected Pregnant Women.

PubMed

Weinberg, Adriana; Muresan, Petronella; Richardson, Kelly; Fenton, Terence; Dominguez, Teresa; Bloom, Anthony; Watts, D Heather; Abzug, Mark J; Nachman, Sharon A; Levin, Myron J

2015-11-01

We investigated the Th1 protective and regulatory T and B cell (Treg and Breg) responses to pH1N1 monovalent influenza vaccine (IIV1) in HIV-infected pregnant women on combination antiretroviral therapy (cART). Peripheral blood mononuclear cells (PBMCs) from 52 study participants were cryopreserved before and after vaccination and analyzed by flow cytometry. pH1N1-specific Th1, Treg, and Breg responses were measured in PBMCs after in vitro stimulation with pH1N1 and control antigen. The cohort analysis did not detect changes in pH1N1-Th1, Treg, or Breg subsets postvaccination. However, individual analyses distinguished subjects who mounted vigorous Th1 responses postvaccination from others who did not. Postvaccination, high pH1N1-Th1 correlated with high pH1N1-Treg and Breg responses, suggesting that low influenza effector responses did not result from excessive vaccine-induced immune regulation. High postvaccination pH1N1-Th1 responses correlated with baseline high PHA- and pH1N1-IFN-γ ELISpot and circulating CD4(+)CD39(+)% and CD8(+)CD39(+)% Treg, with low CD8(+) cell numbers and CD19(+)FOXP3(+)% Breg, but not with CD4(+) cell numbers or HIV viral load. These data highlight the heterogeneity of T cell responses to vaccines in HIV-infected individuals on cART. Predictors of robust Th1 responses to IIV include CD8(+) cell numbers, T cell functionality, and circulating Breg and Treg.

Early Peritoneal Immune Response during Echinococcus granulosus Establishment Displays a Biphasic Behavior

PubMed Central

Mourglia-Ettlin, Gustavo; Marqués, Juan Martín; Chabalgoity, José Alejandro; Dematteis, Sylvia

2011-01-01

Background Cystic echinococcosis is a worldwide distributed helminth zoonosis caused by the larval stage of Echinococcus granulosus. Human secondary cystic echinococcosis is caused by dissemination of protoscoleces after accidental rupture of fertile cysts and is due to protoscoleces ability to develop into new metacestodes. In the experimental model of secondary cystic echinococcosis mice react against protoscoleces producing inefficient immune responses, allowing parasites to develop into cysts. Although the chronic phase of infection has been analyzed in depth, early immune responses at the site of infection establishment, e.g., peritoneal cavity, have not been well studied. Because during early stages of infection parasites are thought to be more susceptible to immune attack, this work focused on the study of cellular and molecular events triggered early in the peritoneal cavity of infected mice. Principal Findings Data obtained showed disparate behaviors among subpopulations within the peritoneal lymphoid compartment. Regarding B cells, there is an active molecular process of plasma cell differentiation accompanied by significant local production of specific IgM and IgG2b antibodies. In addition, peritoneal NK cells showed a rapid increase with a significant percentage of activated cells. Peritoneal T cells showed a substantial increase, with predominance in CD4+ T lymphocytes. There was also a local increase in Treg cells. Finally, cytokine response showed local biphasic kinetics: an early predominant induction of Th1-type cytokines (IFN-γ, IL-2 and IL-15), followed by a shift toward a Th2-type profile (IL-4, IL-5, IL-6, IL-10 and IL-13). Conclusions Results reported here open new ways to investigate the involvement of immune effectors players in E. granulosus establishment, and also in the sequential promotion of Th1- toward Th2-type responses in experimental secondary cystic echinococcosis. These data would be relevant for designing rational therapies based on stimulation of effective responses and blockade of evasion mechanisms. PMID:21912714

A genetic screen to isolate type III effectors translocated into pepper cells during Xanthomonas infection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Julie Anne Roden, Branids Belt, Jason Barzel Ross, Thomas Tachibana, Joe Vargas, Mary Beth Mudgett

2004-11-23

The bacterial pathogen Xanthomonas campestris pv. vesicatoria (Xcv) uses a type III secretion system (TTSS) to translocate effector proteins into host plant cells. The TTSS is required for Xcv colonization, yet the identity of many proteins translocated through this apparatus is not known. We used a genetic screen to functionally identify Xcv TTSS effectors. A transposon 5 (Tn5)-based transposon construct including the coding sequence for the Xcv AvrBs2 effector devoid of its TTSS signal was randomly inserted into the Xcv genome. Insertion of the avrBs2 reporter gene into Xcv genes coding for proteins containing a functional TTSS signal peptide resultedmore » in the creation of chimeric TTSS effector::AvrBs2 fusion proteins. Xcv strains containing these fusions translocated the AvrBs2 reporter in a TTSS-dependent manner into resistant BS2 pepper cells during infection, activating the avrBs2-dependent hypersensitive response (HR). We isolated seven chimeric fusion proteins and designated the identified TTSS effectors as Xanthomonas outer proteins (Xops). Translocation of each Xop was confirmed by using the calmodulin-dependent adenylate cydase reporter assay. Three xop genes are Xanthomonas spp.-specific, whereas homologs for the rest are found in other phytopathogenic bacteria. XopF1 and XopF2 define an effector gene family in Xcv. XopN contains a eukaryotic protein fold repeat and is required for full Xcv pathogenicity in pepper and tomato. The translocated effectors identified in this work expand our knowledge of the diversity of proteins that Xcv uses to manipulate its hosts.« less

Helminth Infections: Recognition and Modulation of the Immune Response by Innate Immune Cells

PubMed Central

Motran, Claudia Cristina; Silvane, Leonardo; Chiapello, Laura Silvina; Theumer, Martin Gustavo; Ambrosio, Laura Fernanda; Volpini, Ximena; Celias, Daiana Pamela; Cervi, Laura

2018-01-01

The survival of helminths in the host over long periods of time is the result of a process of adaptation or dynamic co-evolution between the host and the parasite. However, infection with helminth parasites causes damage to the host tissues producing the release of danger signals that induce the recruitment of various cells, including innate immune cells such as macrophages (Mo), dendritic cells (DCs), eosinophils, basophils, and mast cells. In this scenario, these cells are able to secrete soluble factors, which orchestrate immune effector mechanisms that depend on the different niches these parasites inhabit. Here, we focus on recent advances in the knowledge of excretory-secretory products (ESP), resulting from helminth recognition by DCs and Mo. Phagocytes and other cells types such as innate lymphocyte T cells 2 (ILC2), when activated by ESP, participate in an intricate cytokine network to generate innate and adaptive Th2 responses. In this review, we also discuss the mechanisms of innate immune cell-induced parasite killing and the tissue repair necessary to assure helminth survival over long periods of time. PMID:29670630

TGF-β converts apoptotic stimuli into the signal for Th9 differentiation

PubMed Central

Takami, Mariko; Love, Robert B.; Iwashima, Makio

2012-01-01

Naturally arising CD4+CD25+FoxP3+ regulatory T cells (nTregs) play an essential role in maintenance of immune homeostasis and peripheral tolerance. Previously, we reported that conventional CD4+ and CD8+ T cells undergo p53-induced CD28-dependent apoptosis (PICA) when stimulated with a combination of immobilized anti-CD3 and anti-CD28 antibodies while nTregs expand robustly under the same conditions, suggesting that there is a differential survival mechanism against PICA between conventional T cells and nTregs. Here, we demonstrate that TGF-β signaling is required for nTregs to survive PICA. Conversely, when an active form of exogenous TGF-β is present, conventional T cells become resistant to PICA and undergo robust expansion instead of apoptosis, with reduction of the pro-apoptotic protein Bim and FoxO3a. A substantial fraction of PICA-resisted T cells expressed IL-9 (TH9 cells). Moreover, the presence of IL-6 along with TGF-β led to generation of TH17 cells from conventional T cells. Together, the data demonstrate a novel role for TGF-β in the homeostasis of Tregs and effector T cell differentiation/ expansion. PMID:22461692

IL-15 signaling promotes adoptive effector T-cell survival and memory formation in irradiation-induced lymphopenia.

PubMed

Xu, Aizhang; Bhanumathy, Kalpana Kalyanasundaram; Wu, Jie; Ye, Zhenmin; Freywald, Andrew; Leary, Scot C; Li, Rongxiu; Xiang, Jim

2016-01-01

Lymphopenia promotes naïve T-cell homeostatic proliferation and adoptive effector T-cell survival and memory formation. IL-7 plays a critical role in homeostatic proliferation, survival and memory formation of naïve T-cells in lymphopenia, and its underlying molecular mechanism has also been well studied. However, the mechanism for adoptively transferred effector T-cell survival and memory formation is not fully understood. Here, we transferred in vitro-activated transgenic OT-I CD8(+) effector T-cells into irradiation (600 rads)-induced lymphopenic C57BL/6, IL-7 knockout (KO) and IL-15 KO mice, and investigated the survival and memory formation of transferred T-cells in lymphopenia. We demonstrate that transferred T-cells prolong their survival and enhance their memory in lymphopenic mice, in a manner that depends on IL-15 signaling, but not IL-7. We determine that in vitro stimulation of naïve or effector T-cells with IL-7 and IL-15 reduces IL-7Rα, and increases and/or maintains IL-15Rβ expression, respectively. Consistent with these findings, the expression of IL-7Rα and IL-15Rβ is down- and up-regulated, respectively, in vivo on transferred T-cells in an early phase post T-cell transfer in lymphopenia. We further show that in vitro IL-15 restimulation-induced memory T-cells (compared to IL-2 restimulation-induced effector T-cells) and in vivo transferred T-cells in irradiated IL-15-sufficient C57BL/6 mice (compared to IL-15-deficient IL-15 KO mice) have increased mitochondrial content, but less NADH and lower mitochondrial potential (ΔΨm), and demonstrate greater phosphorylation of signal transducers and activators of transcription-5 (STAT5) and Unc-51-like kinase-1 (ULK1), and higher expression of B-cell leukemia/lymphoma-2 (Bcl2) and memory-, autophagy- and mitochondrial biogenesis-related molecules. Irradiation-induced lymphopenia promotes effector T-cell survival via IL-15 signaling the STAT5/Bcl2 pathway, enhances T-cell memory formation via IL-15 activation of the forkhead-box family of transcription factor (FOXO)/eomesodermin (Eomes) memory and ULK1/autophagy-related gene-7 (ATG7) autophagy pathways, and via IL-15 activation of the mitochondrial remodeling. Our data thus identify some important targets to consider when designing potent adoptive T-cell immunotherapies of cancer.

Cancer resistance of SR/CR mice in the genetic knockout backgrounds of leukocyte effector mechanisms: determinations for functional requirements.

PubMed

Sanders, Anne M; Stehle, John R; Blanks, Michael J; Riedlinger, Gregory; Kim-Shapiro, Jung W; Monjazeb, Arta M; Adams, Jonathan M; Willingham, Mark C; Cui, Zheng

2010-03-31

Spontaneous Regression/Complete Resistant (SR/CR) mice are a colony of cancer-resistant mice that can detect and rapidly destroy malignant cells with innate cellular immunity, predominately mediated by granulocytes. Our previous studies suggest that several effector mechanisms, such as perforin, granzymes, or complements, may be involved in the killing of cancer cells. However, none of these effector mechanisms is known as critical for granulocytes. Additionally, it is unclear which effector mechanisms are required for the cancer killing activity of specific leukocyte populations and the survival of SR/CR mice against the challenges of lethal cancer cells. We hypothesized that if any of these effector mechanisms was required for the resistance to cancer cells, its functional knockout in SR/CR mice should render them sensitive to cancer challenges. This was tested by cross breeding SR/CR mice into the individual genetic knockout backgrounds of perforin (Prf-/-), superoxide (Cybb-/), or inducible nitric oxide (Nos2-/). SR/CR mice were bred into individual Prf-/-, Cybb-/-, or Nos2-/- genetic backgrounds and then challenged with sarcoma 180 (S180). Their overall survival was compared to controls. The cancer killing efficiency of purified populations of macrophages and neutrophils from these immunodeficient mice was also examined. When these genetically engineered mice were challenged with cancer cells, the knockout backgrounds of Prf-/-, Cybb-/-, or Nos2-/- did not completely abolish the SR/CR cancer resistant phenotype. However, the Nos2-/- background did appear to weaken the resistance. Incidentally, it was also observed that the male mice in these immunocompromised backgrounds tended to be less cancer-resistant than SR/CR controls. Despite the previously known roles of perforin, superoxide or nitric oxide in the effector mechanisms of innate immune responses, these effector mechanisms were not required for cancer-resistance in SR/CR mice. The resistance was functional when any one of these effector mechanisms was completely absent, except some noticeably reduced penetrance, but not abolishment, of the phenotype in the male background in comparison to female background. These results also indicate that some other effector mechanism(s) of granulocytes may be involved in the killing of cancer cells in SR/CR mice.

IFN-γ Blocks CD4+CD25+ Tregs and Abolishes Immune Privilege of Minor Histocompatibility Mismatched Corneal Allografts

PubMed Central

Cunnusamy, Khrishen; Niederkorn, Jerry Y.

2014-01-01

Th1 CD4+ cells are believed to be the primary mediators of corneal allograft rejection. However, rejection of fully allogeneic C57BL/6 corneal allografts soared from 50% to 90% in both INF-γ−/− and anti-IFN-γ-treated BALB/c mice. In contrast, similar deficits in IFN-γ in BALB/c hosts enhanced immune privilege of BALB.B (minor histocompatibility antigen-matched, MHC-mismatched) and NZB (major histocompatibility complex-matched, minor histocompatibility antigen-mismatched) corneal allografts – decreasing rejection from 80% to ~20%. This effect of IFN-γ was independent of CD4+ T cell lineage commitment as both anti-IFN-γ-treated acceptor and rejector mice displayed a Th2 cytokine profile. The presence of IFN-γ prevented the generation of alloantigen-specific CD4+CD25+ Tregs in hosts receiving either MHC only mismatched BALB.B or minor only histocompatibility (minor H)-mismatched NZB corneal allografts. Tregs in these hosts, promoted corneal allograft survival by suppressing Th2 effector cells. By contrast, IFN-γ was necessary for the generation of CD4+CD25+ Tregs that prevented rejection of fully allogeneic C57BL/6 corneal allografts in BALB/c hosts. These findings suggest that MHC-matching in combination with blockade of IFN-γ holds promise as a means of enhancing corneal allograft survival. PMID:24119152

Discovery of Novel Secreted Virulence Factors from Salmonella enterica Serovar Typhimurium by Proteomic Analysis of Culture Supernatants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemann, George; Brown, Roslyn N.; Gustin, Jean K.

The intracellular pathogen Salmonella enterica serovar Typhimurium is a leading cause of acute gastroenteritis in the world. This pathogen has two type-III secretion systems (TTSS) necessary for virulence that are encoded in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) and are expressed during extracellular or intracellular infectious states, respectively, to deliver virulence factors (effectors) to the host cell cytoplasm. While many have been identified and at least partially characterized, the full repertoire of effectors has not been catalogued. In this mass spectrometry-based proteomics study, we identified effector proteins secreted under minimal acidic medium growth conditions that induced themore » SPI-2 TTSS and its effectors, and compared the secretome from the parent strain to the secretome from strains missing either essential (SsaK) or regulatory components (SsaL) of the SPI-2 secretion apparatus. We identified 75% of the known TTSS effector repertoire. Excluding translocon components, 95% of the known effectors were biased for identification in the ssaL mutant background, which demonstrated that SsaL regulates SPI-2 type III secretion. To confirm secretion to animal cells, we made translational fusions of several of the best candidates to the calmodulin-dependent adenylate cyclase of Bordetella pertussis and assayed cAMP levels of infected J774 macrophage-like cells. From these infected cells we identified six new TTSS effectors and two others that are secreted independent of TTSS. Our results substantiate reports of additional secretion systems encoded by Salmonella other than TTSS.« less

Peripheral self-reactivity regulates antigen-specific CD8 T-cell responses and cell division under physiological conditions.

PubMed

Swee, Lee Kim; Tan, Zhen Wei; Sanecka, Anna; Yoshida, Nagisa; Patel, Harshil; Grotenbreg, Gijsbert; Frickel, Eva-Maria; Ploegh, Hidde L

2016-11-01

T-cell identity is established by the expression of a clonotypic T-cell receptor (TCR), generated by somatic rearrangement of TCRα and β genes. The properties of the TCR determine both the degree of self-reactivity and the repertoire of antigens that can be recognized. For CD8 T cells, the relationship between TCR identity-hence reactivity to self-and effector function(s) remains to be fully understood and has rarely been explored outside of the H-2 b haplotype. We measured the affinity of three structurally distinct CD8 T-cell-derived TCRs that recognize the identical H-2 L d -restricted epitope, derived from the Rop7 protein of Toxoplasma gondii We used CD8 T cells obtained from mice generated by somatic cell nuclear transfer as the closest approximation of primary T cells with physiological TCR rearrangements and TCR expression levels. First, we demonstrate the common occurrence of secondary rearrangements in endogenously rearranged loci. Furthermore, we characterized and compared the response of Rop7-specific CD8 T-cell clones upon Toxoplasma gondii infection as well as effector function and TCR signalling upon antigenic stimulation in vitro Antigen-independent TCR cross-linking in vitro uncovered profound intrinsic differences in the effector functions between T-cell clones. Finally, by assessing the degree of self-reactivity and comparing the transcriptomes of naive Rop7 CD8 T cells, we show that lower self-reactivity correlates with lower effector capacity, whereas higher self-reactivity is associated with enhanced effector function as well as cell cycle entry under physiological conditions. Altogether, our data show that potential effector functions and basal proliferation of CD8 T cells are set by self-reactivity thresholds. © 2016 The Authors.

New type III effectors from Xanthomonas campestris pv. vesicatoria trigger plant reactions dependent on a conserved N-myristoylation motif.

PubMed

Thieme, Frank; Szczesny, Robert; Urban, Alexander; Kirchner, Oliver; Hause, Gerd; Bonas, Ulla

2007-10-01

Pathogenicity of the gram-negative plant pathogen Xanthomonas campestris pv. vesicatoria depends on a type III secretion system, which translocates bacterial effector proteins into the plant cell. In this study, we identified two novel type III effectors, XopE1 and XopE2 (Xanthomonas outer proteins), using the AvrBs3 effector domain as reporter. XopE1 and XopE2 belong to the HopX family and possess a conserved putative N-myristoylation motif that is also present in the effector XopJ from X. campestris pv. vesicatoria 85-10. XopJ is a member of the YopJ/AvrRxv family of acetyltransferases. Confocal laser scanning microscopy and immunocytochemistry revealed that green fluorescent protein fusions of XopE1, XopE2, and XopJ localized to the plant cell plasma membrane. Targeting to the membrane is probably due to N-myristoylation, because a point mutation in the putative myristoylated glycine residue G2 in XopE1, XopE2, and XopJ resulted in cytoplasmic localization of the mutant proteins. Results of hydroxylamine treatments of XopE2 protein extracts suggest that the proteins are additionally anchored in the host cell plasma membrane by palmitoylation. The membrane localization of the effectors strongly influences the phenotypes they trigger in the plant. Agrobacterium-mediated expression of xopE1 and xopJ in Nicotiana benthamiana led to cell-death reactions that, for xopJ, were dependent on the N-myristoylation motif. In the case of xopE1(G2A), cell death was more pronounced with the mutant than with the wild-type protein. In addition, XopE2 has an avirulence activity in Solanum pseudocapsicum.

Curcumin reverses T cell-mediated adaptive immune dysfunctions in tumor-bearing hosts.

PubMed

Bhattacharyya, Sankar; Md Sakib Hossain, Dewan; Mohanty, Suchismita; Sankar Sen, Gouri; Chattopadhyay, Sreya; Banerjee, Shuvomoy; Chakraborty, Juni; Das, Kaushik; Sarkar, Diptendra; Das, Tanya; Sa, Gaurisankar

2010-07-01

Immune dysfunction is well documented during tumor progression and likely contributes to tumor immune evasion. CD8(+) cytotoxic T lymphocytes (CTLs) are involved in antigen-specific tumor destruction and CD4(+) T cells are essential for helping this CD8(+) T cell-dependent tumor eradication. Tumors often target and inhibit T-cell function to escape from immune surveillance. This dysfunction includes loss of effector and memory T cells, bias towards type 2 cytokines and expansion of T regulatory (Treg) cells. Curcumin has previously been shown to have antitumor activity and some research has addressed the immunoprotective potential of this plant-derived polyphenol in tumor-bearing hosts. Here we examined the role of curcumin in the prevention of tumor-induced dysfunction of T cell-based immune responses. We observed severe loss of both effector and memory T-cell populations, downregulation of type 1 and upregulation of type 2 immune responses and decreased proliferation of effector T cells in the presence of tumors. Curcumin, in turn, prevented this loss of T cells, expanded central memory T cell (T(CM))/effector memory T cell (T(EM)) populations, reversed the type 2 immune bias and attenuated the tumor-induced inhibition of T-cell proliferation in tumor-bearing hosts. Further investigation revealed that tumor burden upregulated Treg cell populations and stimulated the production of the immunosuppressive cytokines transforming growth factor (TGF)-beta and IL-10 in these cells. Curcumin, however, inhibited the suppressive activity of Treg cells by downregulating the production of TGF-beta and IL-10 in these cells. More importantly, curcumin treatment enhanced the ability of effector T cells to kill cancer cells. Overall, our observations suggest that the unique properties of curcumin may be exploited for successful attenuation of tumor-induced suppression of cell-mediated immune responses.

Identification of Novel Host Interactors of Effectors Secreted by Salmonella and Citrobacter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sontag, Ryan L.; Nakayasu, Ernesto S.; Brown, Roslyn N.

Many pathogenic bacteria of the familyEnterobacteriaceaeuse type III secretion systems to inject virulence proteins, termed “effectors,” into the host cell cytosol. Although host-cellular activities of several effectors have been demonstrated, the function and host-targeted pathways of most of the effectors identified to date are largely undetermined. To gain insight into host proteins targeted by bacterial effectors, we performed coaffinity purification of host proteins from cell lysates using recombinant effectors from theEnterobacteriaceaeintracellular pathogensSalmonella entericaserovar Typhimurium andCitrobacter rodentium. We identified 54 high-confidence host interactors for theSalmonellaeffectors GogA, GtgA, GtgE, SpvC, SrfH, SseL, SspH1, and SssB collectively and 21 interactors for theCitrobactereffectors EspT,more » NleA, NleG1, and NleK. We biochemically validated the interaction between the SrfHSalmonellaprotein and the extracellular signal-regulated kinase 2 (ERK2) host protein kinase, which revealed a role for this effector in regulating phosphorylation levels of this enzyme, which plays a central role in signal transduction. IMPORTANCEDuring infection, pathogenic bacteria face an adverse environment of factors driven by both cellular and humoral defense mechanisms. To help evade the immune response and ultimately proliferate inside the host, many bacteria evolved specialized secretion systems to deliver effector proteins directly into host cells. Translocated effector proteins function to subvert host defense mechanisms. Numerous pathogenic bacteria use a specialized secretion system called type III secretion to deliver effectors into the host cell cytosol. Here, we identified 75 new host targets ofSalmonellaandCitrobactereffectors, which will help elucidate their mechanisms of action.« less

Cell Type-Specific Regulation of Immunological Synapse Dynamics by B7 Ligand Recognition

PubMed Central

Brzostek, Joanna; Gascoigne, Nicholas R. J.; Rybakin, Vasily

2016-01-01

B7 proteins CD80 (B7-1) and CD86 (B7-2) are expressed on most antigen-presenting cells and provide critical co-stimulatory or inhibitory input to T cells via their T-cell-expressed receptors: CD28 and CTLA-4. CD28 is expressed on effector T cells and regulatory T cells (Tregs), and CD28-dependent signals are required for optimum activation of effector T cell functions. CD28 ligation on effector T cells leads to formation of distinct molecular patterns and induction of cytoskeletal rearrangements at the immunological synapse (IS). CD28 plays a critical role in recruitment of protein kinase C (PKC)-θ to the effector T cell IS. CTLA-4 is constitutively expressed on the surface of Tregs, but it is expressed on effector T cells only after activation. As CTLA-4 binds to B7 proteins with significantly higher affinity than CD28, B7 ligand recognition by cells expressing both receptors leads to displacement of CD28 and PKC-θ from the IS. In Tregs, B7 ligand recognition leads to recruitment of CTLA-4 and PKC-η to the IS. CTLA-4 plays a role in regulation of T effector and Treg IS stability and cell motility. Due to their important roles in regulating T-cell-mediated responses, B7 receptors are emerging as important drug targets in oncology. In this review, we present an integrated summary of current knowledge about the role of B7 family receptor–ligand interactions in the regulation of spatial and temporal IS dynamics in effector and Tregs. PMID:26870040

Importance of basophils in eosinophilic asthma: the murine counterpart.

PubMed

Poddighe, D; Mathias, C B; Brambilla, I; Marseglia, G L; Oettgen, H C

2018-01-01

Several experimental studies in mice showed that basophils participate in the initiation of Th2 adaptive immune response, in addition to the effector phase. However, the role of basophils in allergic airway inflammation is less clear. The aim of this experiment was to assess the importance of basophils in recruiting inflammatory cells and, in particular, eosinophils in a murine model of asthma induced by Aspergillus fumigatus allergens. Additionally, bronchial reactivity was evaluated. Basophil depletion resulted in a reduction of inflammatory cells in the airways and eosinophil recruitment was significantly impaired. Also bronchial reactivity seemed to be impaired in basophil-depleted mice, but the result was not statistically significant. According to these preliminary data, basophils seem to influence the local eosinophilic response of allergic asthma.

Dendritic Cell Immaturity during Infancy Restricts the Capacity To Express Vaccine-Specific T-Cell Memory

PubMed Central

Upham, John W.; Rate, Angela; Rowe, Julie; Kusel, Merci; Sly, Peter D.; Holt, Patrick G.

2006-01-01

The capacity of the immune system in infants to develop stable T-cell memory in response to vaccination is attenuated, and the mechanism(s) underlying this developmental deficiency in humans is poorly understood. The present study focuses on the capacity for expression of in vitro recall responses to tetanus and diphtheria antigens in lymphocytes from 12-month-old infants vaccinated during the first 6 months of life. We demonstrate that supplementation of infant lymphocytes with “matured” dendritic cells (DC) cultured from autologous CD14+ precursors unmasks previously covert cellular immunity in the form of Th2-skewed cytokine production. Supplementation of adult lymphocytes with comparable prematured autologous DC also boosted vaccine-specific T-cell memory expression, but in contrast to the case for the infants, these cytokine responses were heavily Th1 skewed. Compared to adults, infants had significantly fewer circulating myeloid DC (P < 0.0001) and plasmacytoid DC (P < 0.0001) as a proportion of peripheral blood mononuclear cells. These findings suggest that deficiencies in the numbers of antigen-presenting cells and their functional competence at 12 months of age limit the capacity to express effector memory responses and are potentially a key factor in reduced vaccine responsiveness in infants. PMID:16428758

Structural and Functional Investigations of the Effector Protein LpiR1 from Legionella pneumophila.

PubMed

Beyrakhova, Ksenia A; van Straaten, Karin; Li, Lei; Boniecki, Michal T; Anderson, Deborah H; Cygler, Miroslaw

2016-07-22

Legionella pneumophila is a causative agent of a severe pneumonia, known as Legionnaires' disease. Legionella pathogenicity is mediated by specific virulence factors, called bacterial effectors, which are injected into the invaded host cell by the bacterial type IV secretion system. Bacterial effectors are involved in complex interactions with the components of the host cell immune and signaling pathways, which eventually lead to bacterial survival and replication inside the mammalian cell. Structural and functional studies of bacterial effectors are, therefore, crucial for elucidating the mechanisms of Legionella virulence. Here we describe the crystal structure of the LpiR1 (Lpg0634) effector protein and investigate the effects of its overexpression in mammalian cells. LpiR1 is an α-helical protein that consists of two similar domains aligned in an antiparallel fashion. The hydrophilic cleft between the domains might serve as a binding site for a potential host cell interaction partner. LpiR1 binds the phosphate group at a conserved site and is stabilized by Mn(2+), Ca(2+), or Mg(2+) ions. When overexpressed in mammalian cells, a GFP-LpiR1 fusion protein is localized in the cytoplasm. Intracellular signaling antibody array analysis revealed small changes in the phosphorylation state of several components of the Akt signaling pathway in HEK293T cells overexpressing LpiR1. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Human eosinophils modulate peripheral blood mononuclear cell response to Schistosoma mansoni adult worm antigen in vitro.

PubMed

Tweyongyere, R; Namanya, H; Naniima, P; Cose, S; Tukahebwa, E M; Elliott, A M; Dunne, D W; Wilson, S

2016-08-01

High numbers of eosinophils are observed in parasitic infections and allergic diseases, where they are proposed to be terminally differentiated effector cells that play beneficial role in host defence, or cause harmful inflammatory response. Eosinophils have been associated with killing of schistosomulae in vitro, but there is growing evidence that eosinophils can play additional immuno-regulatory role. Here, we report results of a study that examines peripheral blood mononuclear cell (PBMC) cytokine responses to Schistosoma mansoni adult worm antigen (SWA) when stimulated alone or enriched with autologous eosinophils. Production of the Th-2 type cytokines interleukin (IL)-4, IL-5 and IL-13 was lower (P = 0·017, 0·018 and <0·001, respectively) in PBMC + eosinophil cultures than in PBMC-only cultures stimulated with SWA. Substantial levels of IL-13, IL-10, interferon gamma and tumour necrosis factor alpha were recorded in cultures of eosinophils, but none of these cytokines showed significant association with the observed eosinophil-induced drop in cytokine responses of PBMC. Transwell experiments suggested that the observed effect is due to soluble mediators that downmodulate production of Th-2 type cytokines. This study shows that eosinophils may down-modulate schistosome-specific Th-2 type cytokine responses in S. mansoni-infected individuals. The mechanism of this immune modulation remains to be elucidated. © 2016 The Authors. Parasite Immunology Published by John Wiley & Sons Ltd.

Identification of Nascent Memory CD8 T Cells and Modeling of Their Ontogeny.

PubMed

Crauste, Fabien; Mafille, Julien; Boucinha, Lilia; Djebali, Sophia; Gandrillon, Olivier; Marvel, Jacqueline; Arpin, Christophe

2017-03-22

Primary immune responses generate short-term effectors and long-term protective memory cells. The delineation of the genealogy linking naive, effector, and memory cells has been complicated by the lack of phenotypes discriminating effector from memory differentiation stages. Using transcriptomics and phenotypic analyses, we identify Bcl2 and Mki67 as a marker combination that enables the tracking of nascent memory cells within the effector phase. We then use a formal approach based on mathematical models describing the dynamics of population size evolution to test potential progeny links and demonstrate that most cells follow a linear naive→early effector→late effector→memory pathway. Moreover, our mathematical model allows long-term prediction of memory cell numbers from a few early experimental measurements. Our work thus provides a phenotypic means to identify effector and memory cells, as well as a mathematical framework to investigate their genealogy and to predict the outcome of immunization regimens in terms of memory cell numbers generated. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Non-replicating adenovirus vectors expressing avian influenza virus hemagglutinin and nucleocapsid proteins induce chicken specific effector, memory and effector memory CD8+ T lymphocytes

PubMed Central

Singh, Shailbala; Toro, Haroldo; Tang, De-Chu; Briles, Worthie E.; Yates, Linda M.; Kopulos, Renee T.; Collisson, Ellen W.

2010-01-01

Avian influenza virus (AIV) specific CD8+ T lymphocyte responses stimulated by intramuscular administration of an adenovirus (Ad) vector expressing either HA or NP were evaluated in chickens following ex vivo stimulation by non-professional antigen presenting cells. The CD8+ T lymphocyte responses were AIV specific, MHC-I restricted, and cross-reacted with heterologousH7N2 AIV strain. Specific effector responses, at 10 days post-inoculation (p.i.), were undetectable at 2 weeks p.i., and memory responses were detected from 3 to 8 weeks p.i. Effector memory responses, detected 1 week following a booster inoculation, were significantly greater than the primary responses and, within 7 days, declined to undetectable levels. Inoculation of an Ad-vector expressing human NP resulted in significantly greater MHC restricted, activation of CD8+ T cell responses specific for AIV. Decreases in all responses with time were most dramatic with maximum activation of T cells as observed following effector and effector memory responses. PMID:20557918

Regulation of Asymmetric Division by Atypical Protein Kinase C Influences Early Specification of CD8+ T Lymphocyte Fates

PubMed Central

Metz, Patrick J.; Lopez, Justine; Kim, Stephanie H.; Akimoto, Kazunori; Ohno, Shigeo; Chang, John T.

2016-01-01

Naïve CD8+ T lymphocytes responding to microbial pathogens give rise to effector T cells that provide acute defense and memory T cells that provide long-lived immunity. Upon activation, CD8+ T lymphocytes can undergo asymmetric division, unequally distributing factors to the nascent daughter cells that influence their eventual fate towards the effector or memory lineages. Individual loss of either atypical protein kinase C (aPKC) isoform, PKCζ or PKCλ/ι, partially impairs asymmetric divisions and increases CD8+ T lymphocyte differentiation toward a long-lived effector fate at the expense of memory T cell formation. Here, we show that deletion of both aPKC isoforms resulted in a deficit in asymmetric divisions, increasing the proportion of daughter cells that inherit high amounts of effector fate-associated molecules, IL-2Rα, T-bet, IFNγR, and interferon regulatory factor 4 (IRF4). However, unlike CD8+ T cells deficient in only one aPKC isoform, complete loss of aPKC unexpectedly increased CD8+ T cell differentiation toward a short-lived, terminal effector fate, as evidenced by increased rates of apoptosis and decreased expression of Eomes and Bcl2 early during the immune response. Together, these results provide evidence for an important role for asymmetric division in CD8+ T lymphocyte fate specification by regulating the balance between effector and memory precursors at the initiation of the adaptive immune response. PMID:26765121

Stromal interaction molecules 1 and 2 are key regulators of autoreactive T cell activation in murine autoimmune central nervous system inflammation.

PubMed

Schuhmann, Michael K; Stegner, David; Berna-Erro, Alejandro; Bittner, Stefan; Braun, Attila; Kleinschnitz, Christoph; Stoll, Guido; Wiendl, Heinz; Meuth, Sven G; Nieswandt, Bernhard

2010-02-01

Calcium (Ca(2+)) signaling in T lymphocytes is essential for a variety of functions, including the regulation of differentiation, gene transcription, and effector functions. A major Ca(2+) entry pathway in nonexcitable cells, including T cells, is store-operated Ca(2+) entry (SOCE), wherein depletion of intracellular Ca(2+) stores upon receptor stimulation causes subsequent influx of extracellular Ca(2+) across the plasma membrane. Stromal interaction molecule (STIM) 1 is the Ca(2+) sensor in the endoplasmic reticulum, which controls this process, whereas the other STIM isoform, STIM2, coregulates SOCE. Although the contribution of STIM molecules and SOCE to T lymphocyte function is well studied in vitro, their significance for immune processes in vivo has remained largely elusive. In this study, we studied T cell function in mice lacking STIM1 or STIM2 in a model of myelin-oligodendrocyte glycoprotein (MOG(35-55))-induced experimental autoimmune encephalomyelitis (EAE). We found that STIM1 deficiency significantly impaired the generation of neuroantigen-specific T cell responses in vivo with reduced Th1/Th17 responses, resulting in complete protection from EAE. Mice lacking STIM2 developed EAE, but the disease course was ameliorated. This was associated with a reduced clinical peak of disease. Deficiency of STIM2 was associated with an overall reduced proliferative capacity of lymphocytes and a reduction of IFN-gamma/IL-17 production by neuroantigen-specific T cells. Neither STIM1 nor STIM2 deficiency altered the phenotype or function of APCs. These findings reveal a crucial role of STIM-dependent pathways for T cell function and activation under autoimmune inflammatory conditions, establishing them as attractive new molecular therapeutic targets for the treatment of inflammatory and autoimmune disorders.

Granulocyte Macrophage Colony-Stimulating Factor-Activated Eosinophils Promote Interleukin-23 Driven Chronic Colitis

PubMed Central

Griseri, Thibault; Arnold, Isabelle C.; Pearson, Claire; Krausgruber, Thomas; Schiering, Chris; Franchini, Fanny; Schulthess, Julie; McKenzie, Brent S.; Crocker, Paul R.; Powrie, Fiona

2015-01-01

Summary The role of intestinal eosinophils in immune homeostasis is enigmatic and the molecular signals that drive them from protective to tissue damaging are unknown. Most commonly associated with Th2 cell-mediated diseases, we describe a role for eosinophils as crucial effectors of the interleukin-23 (IL-23)-granulocyte macrophage colony-stimulating factor (GM-CSF) axis in colitis. Chronic intestinal inflammation was characterized by increased bone marrow eosinopoiesis and accumulation of activated intestinal eosinophils. IL-5 blockade or eosinophil depletion ameliorated colitis, implicating eosinophils in disease pathogenesis. GM-CSF was a potent activator of eosinophil effector functions and intestinal accumulation, and GM-CSF blockade inhibited chronic colitis. By contrast neutrophil accumulation was GM-CSF independent and dispensable for colitis. In addition to TNF secretion, release of eosinophil peroxidase promoted colitis identifying direct tissue-toxic mechanisms. Thus, eosinophils are key perpetrators of chronic inflammation and tissue damage in IL-23-mediated immune diseases and it suggests the GM-CSF-eosinophil axis as an attractive therapeutic target. PMID:26200014

Impaired Th1 immunity in ovarian cancer patients is mediated by TNFR2+ Tregs within the tumor microenvironment.

PubMed

Govindaraj, Chindu; Scalzo-Inguanti, Karen; Madondo, Mutsa; Hallo, Julene; Flanagan, Katie; Quinn, Michael; Plebanski, Magdalena

2013-10-01

Ovarian cancer is a prevalent gynecological malignancy with potent immune-suppression capabilities; regulatory T cells (Tregs) are significant contributors to this immune-suppression. As ovarian cancer patients present with high levels of TNF and Tregs expressing TNFR2 are associated with maximal suppressive capacity, we investigated TNFR2+ Tregs within these patients. Indeed, TNFR2+ Tregs from tumor-associated ascites were the most potent suppressor T cell fraction. They were abundantly present within the ascites and more suppressive than peripheral blood TNFR2+ Tregs in patients. The increased suppressive capacity can be explained by a distinct cell surface expression profile, which includes high levels of CD39, CD73, TGF-β and GARP. Additionally, CD73 expression level on TNFR2+ Tregs was inversely correlated with IFN-γ production by effector T cells. This Treg fraction can be selectively recruited into the ascites from the peripheral blood of patients. Targeting TNFR2+ Tregs may offer new approaches to enhance the poor survival rates of ovarian cancer. © 2013.

IRF4 Deficiency Abrogates Lupus Nephritis Despite Enhancing Systemic Cytokine Production

PubMed Central

Lech, Maciej; Weidenbusch, Marc; Kulkarni, Onkar P.; Ryu, Mi; Darisipudi, Murthy Narayana; Susanti, Heni Eka; Mittruecker, Hans-Willi; Mak, Tak W.

2011-01-01

The IFN-regulatory factors IRF1, IRF3, IRF5, and IRF7 modulate processes involved in the pathogenesis of systemic lupus and lupus nephritis, but the contribution of IRF4, which has multiple roles in innate and adaptive immunity, is unknown. To determine a putative pathogenic role of IRF4 in lupus, we crossed Irf4-deficient mice with autoimmune C57BL/6-(Fas)lpr mice. IRF4 deficiency associated with increased activation of antigen-presenting cells in C57BL/6-(Fas)lpr mice, resulting in a massive increase in plasma levels of TNF and IL-12p40, suggesting that IRF4 suppresses cytokine release in these mice. Nevertheless, IRF4 deficiency completely protected these mice from glomerulonephritis and lung disease. The mice were hypogammaglobulinemic and lacked antinuclear and anti-dsDNA autoantibodies, revealing the requirement of IRF4 for the maturation of plasma cells. As a consequence, Irf4-deficient C57BL/6-(Fas)lpr mice neither developed immune complex disease nor glomerular activation of complement. In addition, lack of IRF4 impaired the maturation of Th17 effector T cells and reduced plasma levels of IL-17 and IL-21, which are cytokines known to contribute to autoimmune tissue injury. In summary, IRF4 deficiency enhances systemic inflammation and the activation of antigen-presenting cells but also prevents the maturation of plasma cells and effector T cells. Because these adaptive immune effectors are essential for the evolution of lupus nephritis, we conclude that IRF4 promotes the development of lupus nephritis despite suppressing antigen-presenting cells. PMID:21742731

Potato NPH3/RPT2-Like Protein StNRL1, Targeted by a Phytophthora infestans RXLR Effector, Is a Susceptibility Factor.

PubMed

Yang, Lina; McLellan, Hazel; Naqvi, Shaista; He, Qin; Boevink, Petra C; Armstrong, Miles; Giuliani, Licida M; Zhang, Wei; Tian, Zhendong; Zhan, Jiasui; Gilroy, Eleanor M; Birch, Paul R J

2016-05-01

Plant pathogens deliver effectors to manipulate host processes. We know little about how fungal and oomycete effectors target host proteins to promote susceptibility, yet such knowledge is vital to understand crop disease. We show that either transient expression in Nicotiana benthamiana, or stable transgenic expression in potato (Solanum tuberosum), of the Phytophthora infestans RXLR effector Pi02860 enhances leaf colonization by the pathogen. Expression of Pi02860 also attenuates cell death triggered by the P. infestans microbe-associated molecular pattern INF1, indicating that the effector suppresses pattern-triggered immunity. However, the effector does not attenuate cell death triggered by Cf4/Avr4 coexpression, showing that it does not suppress all cell death activated by cell surface receptors. Pi02860 interacts in yeast two-hybrid assays with potato NPH3/RPT2-LIKE1 (NRL1), a predicted CULLIN3-associated ubiquitin E3 ligase. Interaction of Pi02860 in planta was confirmed by coimmunoprecipitation and bimolecular fluorescence complementation assays. Virus-induced gene silencing of NRL1 in N. benthamiana resulted in reduced P. infestans colonization and accelerated INF1-mediated cell death, indicating that this host protein acts as a negative regulator of immunity. Moreover, whereas NRL1 virus-induced gene silencing had no effect on the ability of the P. infestans effector Avr3a to suppress INF1-mediated cell death, such suppression by Pi02860 was significantly attenuated, indicating that this activity of Pi02860 is mediated by NRL1. Transient overexpression of NRL1 resulted in the suppression of INF1-mediated cell death and enhanced P. infestans leaf colonization, demonstrating that NRL1 acts as a susceptibility factor to promote late blight disease. © 2016 American Society of Plant Biologists. All Rights Reserved.

Enhanced ADCC Activity of Affinity Maturated and Fc-Engineered Mini-Antibodies Directed against the AML Stem Cell Antigen CD96

PubMed Central

Kellner, Christian; Bräutigam, Joachim; Staudinger, Matthias; Schub, Natalie; Peipp, Matthias; Gramatzki, Martin; Humpe, Andreas

2012-01-01

CD96, a cell surface antigen recently described to be preferentially expressed on acute myeloid leukemia (AML) leukemic stem cells (LSC) may represent an interesting target structure for the development of antibody-based therapeutic approaches. The v-regions from the CD96-specific hybridoma TH-111 were isolated and used to generate a CD96-specific single chain fragment of the variable regions (scFv). An affinity maturated variant resulting in 4-fold enhanced CD96-binding was generated by random mutagenesis and stringent selection using phage display. The affinity maturated scFv CD96-S32F was used to generate bivalent mini-antibodies by genetically fusing an IgG1 wild type Fc region or a variant with enhanced CD16a binding. Antibody dependent cell-mediated cytotoxicity (ADCC) experiments revealed that Fc engineering was essential to trigger significant effector cell-mediated lysis when the wild type scFv was used. The mini-antibody variant generated by fusing the affinity-maturated scFv with the optimized Fc variant demonstrated the highest ADCC activity (2.3-fold enhancement in efficacy). In conclusion, our data provide proof of concept that CD96 could serve as a target structure for effector cell-mediated lysis and demonstrate that both enhancing affinity for CD96 and for CD16a resulted in mini-antibodies with the highest cytolytic potential. PMID:22879978

Combined dendritic cell cryotherapy of tumor induces systemic antimetastatic immunity.

PubMed

Machlenkin, Arthur; Goldberger, Ofir; Tirosh, Boaz; Paz, Adrian; Volovitz, Ilan; Bar-Haim, Erez; Lee, Sung-Hyung; Vadai, Ezra; Tzehoval, Esther; Eisenbach, Lea

2005-07-01

Cryotherapy of localized prostate, renal, and hepatic primary tumors and metastases is considered a minimally invasive treatment demonstrating a low complication rate in comparison with conventional surgery. The main drawback of cryotherapy is that it has no systemic effect on distant metastases. We investigated whether intratumoral injections of dendritic cells following cryotherapy of local tumors (cryoimmunotherapy) provides an improved approach to cancer treatment, combining local tumor destruction and systemic anticancer immunity. The 3LL murine Lewis lung carcinoma clone D122 and the ovalbumin-transfected B16 melanoma clone MO5 served as models for spontaneous metastasis. The antimetastatic effect of cryoimmunotherapy was assessed in the lung carcinoma model by monitoring mouse survival, lung weight, and induction of tumor-specific CTLs. The mechanism of cryoimmunotherapy was elucidated in the melanoma model using adoptive transfer of T cell receptor transgenic OT-I CTLs into the tumor-bearing mice, and analysis of Th1/Th2 responses by intracellular cytokine staining in CD4 and CD8 cells. Cryoimmunotherapy caused robust and tumor-specific CTL responses, increased Th1 responses, significantly prolonged survival and dramatically reduced lung metastasis. Although intratumor administration of dendritic cells alone increased the proliferation rate of CD8 cells, only cryoimmunotherapy resulted in the generation of effector memory cells. Furthermore, cryoimmunotherapyprotected mice that had survived primary MO5 tumors from rechallenge with parental tumors. These results present cryoimmunotherapy as a novel approach for systemic treatment of cancer. We envisage that cryotherapy of tumors combined with subsequent in situ immunotherapy by autologous unmodified immature dendritic cells can be applied in practice.

Effector CD8 T cells dedifferentiate into long-lived memory cells.

PubMed

Youngblood, Ben; Hale, J Scott; Kissick, Haydn T; Ahn, Eunseon; Xu, Xiaojin; Wieland, Andreas; Araki, Koichi; West, Erin E; Ghoneim, Hazem E; Fan, Yiping; Dogra, Pranay; Davis, Carl W; Konieczny, Bogumila T; Antia, Rustom; Cheng, Xiaodong; Ahmed, Rafi

2017-12-21

Memory CD8 T cells that circulate in the blood and are present in lymphoid organs are an essential component of long-lived T cell immunity. These memory CD8 T cells remain poised to rapidly elaborate effector functions upon re-exposure to pathogens, but also have many properties in common with naive cells, including pluripotency and the ability to migrate to the lymph nodes and spleen. Thus, memory cells embody features of both naive and effector cells, fuelling a long-standing debate centred on whether memory T cells develop from effector cells or directly from naive cells. Here we show that long-lived memory CD8 T cells are derived from a subset of effector T cells through a process of dedifferentiation. To assess the developmental origin of memory CD8 T cells, we investigated changes in DNA methylation programming at naive and effector cell-associated genes in virus-specific CD8 T cells during acute lymphocytic choriomeningitis virus infection in mice. Methylation profiling of terminal effector versus memory-precursor CD8 T cell subsets showed that, rather than retaining a naive epigenetic state, the subset of cells that gives rise to memory cells acquired de novo DNA methylation programs at naive-associated genes and became demethylated at the loci of classically defined effector molecules. Conditional deletion of the de novo methyltransferase Dnmt3a at an early stage of effector differentiation resulted in reduced methylation and faster re-expression of naive-associated genes, thereby accelerating the development of memory cells. Longitudinal phenotypic and epigenetic characterization of the memory-precursor effector subset of virus-specific CD8 T cells transferred into antigen-free mice revealed that differentiation to memory cells was coupled to erasure of de novo methylation programs and re-expression of naive-associated genes. Thus, epigenetic repression of naive-associated genes in effector CD8 T cells can be reversed in cells that develop into long-lived memory CD8 T cells while key effector genes remain demethylated, demonstrating that memory T cells arise from a subset of fate-permissive effector T cells.

Th17 cell-mediated immune responses promote mast cell proliferation by triggering stem cell factor in keratinocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee

Although mast cells are traditionally thought to function as effector cells in allergic responses, they have increasingly been recognized as important regulators of various immune responses. Mast cells mature locally; thus, tissue-specific influences are important for promoting mast cell accumulation and survival in the skin and the gastrointestinal tract. In this study, we determined the effects of keratinocytes on mast cell accumulation during Th17-mediated skin inflammation. We observed increases in dermal mast cells in imiquimod-induced psoriatic dermatitis in mice accompanied by the expression of epidermal stem cell factor (SCF), a critical mast cell growth factor. Similar to mouse epidermal keratinocytes,more » SCF was highly expressed in the human HaCaT keratinocyte cell line following stimulation with IL−17. Further, keratinocytes promoted mast cell proliferation following stimulation with IL−17 in vitro. However, the effects of keratinocytes on mast cells were significantly diminished in the presence of anti−CD117 (stem cell factor receptor) blocking antibodies. Taken together, our results revealed that the Th17-mediated inflammatory environment promotes mast cell accumulation through keratinocyte-derived SCF. - Highlights: • Psoriasis-like skin inflammation increase dermal mast cells. • Keratinocyte produce stem cell factor in psoriasis-like skin inflammation. • Keratinocyte promote mast cell proliferation by stem cell factor dependent manner.« less

A central role for Notch in effector CD8+ T cell differentiation

PubMed Central

Backer, Ronald A.; Helbig, Christina; Gentek, Rebecca; Kent, Andrew; Laidlaw, Brian J.; Dominguez, Claudia X.; de Souza, Yevan S.; van Trierum, Stella E.; van Beek, Ruud; Rimmelzwaan, Guus F.; ten Brinke, Anja; Willemsen, A. Marcel; van Kampen, Antoine H. C.; Kaech, Susan M.; Blander, J. Magarian; van Gisbergen, Klaas; Amsen, Derk

2014-01-01

Activated CD8+ T cells choose between terminal effector cell (TEC) or memory precursor cell (MPC) fates. We show that Notch controls this choice. Notch promoted differentiation of immediately protective TECs and was correspondingly required for clearance of an acute influenza virus infection. Notch activated a major portion of the TEC-specific gene expression program and suppressed the MPC-specific program. Expression of Notch receptors was induced on naïve CD8+ T cells by inflammatory mediators and interleukin 2 (IL-2) via mTOR and T-bet dependent pathways. These pathways were subsequently amplified downstream of Notch, creating a positive feedback loop. Notch thus functions as a central hub where information from different sources converges to match effector T cell differentiation to the demands of the infection. PMID:25344724

Glioblastoma-targeted CD4+ CAR T cells mediate superior antitumor activity.

PubMed

Wang, Dongrui; Aguilar, Brenda; Starr, Renate; Alizadeh, Darya; Brito, Alfonso; Sarkissian, Aniee; Ostberg, Julie R; Forman, Stephen J; Brown, Christine E

2018-05-17

Chimeric antigen receptor-modified (CAR-modified) T cells have shown promising therapeutic effects for hematological malignancies, yet limited and inconsistent efficacy against solid tumors. The refinement of CAR therapy requires an understanding of the optimal characteristics of the cellular products, including the appropriate composition of CD4+ and CD8+ subsets. Here, we investigated the differential antitumor effect of CD4+ and CD8+ CAR T cells targeting glioblastoma-associated (GBM-associated) antigen IL-13 receptor α2 (IL13Rα2). Upon stimulation with IL13Rα2+ GBM cells, the CD8+ CAR T cells exhibited robust short-term effector function but became rapidly exhausted. By comparison, the CD4+ CAR T cells persisted after tumor challenge and sustained their effector potency. Mixing with CD4+ CAR T cells failed to ameliorate the effector dysfunction of CD8+ CAR T cells, while surprisingly, CD4+ CAR T cell effector potency was impaired when coapplied with CD8+ T cells. In orthotopic GBM models, CD4+ outperformed CD8+ CAR T cells, especially for long-term antitumor response. Further, maintenance of the CD4+ subset was positively correlated with the recursive killing ability of CAR T cell products derived from GBM patients. These findings identify CD4+ CAR T cells as a highly potent and clinically important T cell subset for effective CAR therapy.

Glioblastoma-targeted CD4+ CAR T cells mediate superior antitumor activity

PubMed Central

Wang, Dongrui; Starr, Renate; Alizadeh, Darya; Brito, Alfonso; Sarkissian, Aniee; Ostberg, Julie R.; Forman, Stephen J.; Brown, Christine E.

2018-01-01

Chimeric antigen receptor–modified (CAR-modified) T cells have shown promising therapeutic effects for hematological malignancies, yet limited and inconsistent efficacy against solid tumors. The refinement of CAR therapy requires an understanding of the optimal characteristics of the cellular products, including the appropriate composition of CD4+ and CD8+ subsets. Here, we investigated the differential antitumor effect of CD4+ and CD8+ CAR T cells targeting glioblastoma-associated (GBM-associated) antigen IL-13 receptor α2 (IL13Rα2). Upon stimulation with IL13Rα2+ GBM cells, the CD8+ CAR T cells exhibited robust short-term effector function but became rapidly exhausted. By comparison, the CD4+ CAR T cells persisted after tumor challenge and sustained their effector potency. Mixing with CD4+ CAR T cells failed to ameliorate the effector dysfunction of CD8+ CAR T cells, while surprisingly, CD4+ CAR T cell effector potency was impaired when coapplied with CD8+ T cells. In orthotopic GBM models, CD4+ outperformed CD8+ CAR T cells, especially for long-term antitumor response. Further, maintenance of the CD4+ subset was positively correlated with the recursive killing ability of CAR T cell products derived from GBM patients. These findings identify CD4+ CAR T cells as a highly potent and clinically important T cell subset for effective CAR therapy. PMID:29769444

Neem leaf glycoprotein promotes dual generation of central and effector memory CD8(+) T cells against sarcoma antigen vaccine to induce protective anti-tumor immunity.

PubMed

Ghosh, Sarbari; Sarkar, Madhurima; Ghosh, Tithi; Guha, Ipsita; Bhuniya, Avishek; Saha, Akata; Dasgupta, Shayani; Barik, Subhasis; Bose, Anamika; Baral, Rathindranath

2016-03-01

We have previously shown that Neem Leaf Glycoprotein (NLGP) mediates sustained tumor protection by activating host immune response. Now we report that adjuvant help from NLGP predominantly generates CD44(+)CD62L(high)CCR7(high) central memory (TCM; in lymph node) and CD44(+)CD62L(low)CCR7(low) effector memory (TEM; in spleen) CD8(+) T cells of Swiss mice after vaccination with sarcoma antigen (SarAg). Generated TCM and TEM participated either to replenish memory cell pool for sustained disease free states or in rapid tumor eradication respectively. TCM generated after SarAg+NLGP vaccination underwent significant proliferation and IL-2 secretion following SarAg re-stimulation. Furthermore, SarAg+NLGP vaccination helps in greater survival of the memory precursor effector cells at the peak of the effector response and their maintenance as mature memory cells, in comparison to single modality treatment. Such response is corroborated with the reduced phosphorylation of FOXO in the cytosol and increased KLF2 in the nucleus associated with enhanced CD62L, CCR7 expression of lymph node-resident CD8(+) T cells. However, spleen-resident CD8(+) T memory cells show superior efficacy for immediate memory-to-effector cell conversion. The data support in all aspects that SarAg+NLGP demonstrate superiority than SarAg vaccination alone that benefits the host by rapid effector functions whenever required, whereas, central-memory cells are thought to replenish the memory cell pool for ultimate sustained disease free survival till 60 days following post-vaccination tumor inoculation. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Shigella Type Three Secretion System Effector OspG Directly and Specifically Binds to Host Ubiquitin for Activation

PubMed Central

Zhou, Yan; Dong, Na; Hu, Liyan; Shao, Feng

2013-01-01

The genus Shigella infects human gut epithelial cells to cause diarrhea and gastrointestinal disorders. Like many other Gram-negative bacterial pathogens, the virulence of Shigella spp. relies on a conserved type three secretion system that delivers a handful of effector proteins into host cells to manipulate various host cell physiology. However, many of the Shigella type III effectors remain functionally uncharacterized. Here we observe that OspG, one of the Shigella effectors, interacted with ubiquitin conjugates and poly-ubiquitin chains of either K48 or K63 linkage in eukaryotic host cells. Purified OspG protein formed a stable complex with ubiquitin but showed no interactions with other ubiquitin-like proteins. OspG binding to ubiquitin required the carboxyl terminal helical region in OspG and the canonical I44-centered hydrophobic surface in ubiquitin. OspG and OspG-homologous effectors, NleH1/2 from enteropathogenic E coli (EPEC), contain sub-domains I-VII of eukaryotic serine/threonine kinase. GST-tagged OspG and NleH1/2 could undergo autophosphorylation, the former of which was significantly stimulated by ubiquitin binding. Ubiquitin binding was also required for OspG functioning in attenuating host NF-κB signaling. Our data illustrate a new mechanism that bacterial pathogen like Shigella exploits ubiquitin binding to activate its secreted virulence effector for its functioning in host eukaryotic cells. PMID:23469023

Large-Scale Identification and Characterization of Heterodera avenae Putative Effectors Suppressing or Inducing Cell Death in Nicotiana benthamiana

PubMed Central

Chen, Changlong; Chen, Yongpan; Jian, Heng; Yang, Dan; Dai, Yiran; Pan, Lingling; Shi, Fengwei; Yang, Shanshan; Liu, Qian

2018-01-01

Heterodera avenae is one of the most important plant pathogens and causes vast losses in cereal crops. As a sedentary endoparasitic nematode, H. avenae secretes effectors that modify plant defenses and promote its biotrophic infection of its hosts. However, the number of effectors involved in the interaction between H. avenae and host defenses remains unclear. Here, we report the identification of putative effectors in H. avenae that regulate plant defenses on a large scale. Our results showed that 78 of the 95 putative effectors suppressed programmed cell death (PCD) triggered by BAX and that 7 of the putative effectors themselves caused cell death in Nicotiana benthamiana. Among the cell-death-inducing effectors, three were found to be dependent on their specific domains to trigger cell death and to be expressed in esophageal gland cells by in situ hybridization. Ten candidate effectors that suppressed BAX-triggered PCD also suppressed PCD triggered by the elicitor PsojNIP and at least one R-protein/cognate effector pair, suggesting that they are active in suppressing both pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). Notably, with the exception of isotig16060, these putative effectors could also suppress PCD triggered by cell-death-inducing effectors from H. avenae, indicating that those effectors may cooperate to promote nematode parasitism. Collectively, our results indicate that the majority of the tested effectors of H. avenae may play important roles in suppressing cell death induced by different elicitors in N. benthamiana. PMID:29379510

High salt reduces the activation of IL-4- and IL-13-stimulated macrophages.

PubMed

Binger, Katrina J; Gebhardt, Matthias; Heinig, Matthias; Rintisch, Carola; Schroeder, Agnes; Neuhofer, Wolfgang; Hilgers, Karl; Manzel, Arndt; Schwartz, Christian; Kleinewietfeld, Markus; Voelkl, Jakob; Schatz, Valentin; Linker, Ralf A; Lang, Florian; Voehringer, David; Wright, Mark D; Hubner, Norbert; Dechend, Ralf; Jantsch, Jonathan; Titze, Jens; Müller, Dominik N

2015-11-02

A high intake of dietary salt (NaCl) has been implicated in the development of hypertension, chronic inflammation, and autoimmune diseases. We have recently shown that salt has a proinflammatory effect and boosts the activation of Th17 cells and the activation of classical, LPS-induced macrophages (M1). Here, we examined how the activation of alternative (M2) macrophages is affected by salt. In stark contrast to Th17 cells and M1 macrophages, high salt blunted the alternative activation of BM-derived mouse macrophages stimulated with IL-4 and IL-13, M(IL-4+IL-13) macrophages. Salt-induced reduction of M(IL-4+IL-13) activation was not associated with increased polarization toward a proinflammatory M1 phenotype. In vitro, high salt decreased the ability of M(IL-4+IL-13) macrophages to suppress effector T cell proliferation. Moreover, mice fed a high salt diet exhibited reduced M2 activation following chitin injection and delayed wound healing compared with control animals. We further identified a high salt-induced reduction in glycolysis and mitochondrial metabolic output, coupled with blunted AKT and mTOR signaling, which indicates a mechanism by which NaCl inhibits full M2 macrophage activation. Collectively, this study provides evidence that high salt reduces noninflammatory innate immune cell activation and may thus lead to an overall imbalance in immune homeostasis.

Identification of the Vibrio parahaemolyticus type III secretion system 2-associated chaperone VocC for the T3SS2-specific effector VopC.

PubMed

Akeda, Yukihiro; Kodama, Toshio; Saito, Kazunobu; Iida, Tetsuya; Oishi, Kazunori; Honda, Takeshi

2011-11-01

The enteropathogen Vibrio parahaemolyticus possesses two sets of type III secretion systems, T3SS1 and T3SS2. Effector proteins secreted by these T3SSs are delivered into host cells, leading to cell death or diarrhea. However, it is not known how specific effectors are secreted through a specific T3SS when both T3SSs are expressed within bacteria. One molecule thought to determine secretion specificity is a T3SS-associated chaperone; however, no T3SS2-specific chaperone has been identified. Therefore, we screened T3SS2 chaperone candidates by a pull-down assay using T3SS2 effectors fused with glutathione-S-transferase. A secretion assay revealed that the newly identified cognate chaperone VocC for the T3SS2-specific effector VopC was required for the efficient secretion of the substrate through T3SS2. Further experiments determined the chaperone-binding domain and the amino-terminal secretion signal of the cognate effector. These findings, in addition to the previously identified T3SS1-specific chaperone, VecA, provide a strategy to clarify the specificity of effector secretion through T3SSs of V. parahaemolyticus. 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Dedicator of cytokinesis 8-deficient CD4+ T cells are biased to a TH2 effector fate at the expense of TH1 and TH17 cells.

PubMed

Tangye, Stuart G; Pillay, Bethany; Randall, Katrina L; Avery, Danielle T; Phan, Tri Giang; Gray, Paul; Ziegler, John B; Smart, Joanne M; Peake, Jane; Arkwright, Peter D; Hambleton, Sophie; Orange, Jordan; Goodnow, Christopher C; Uzel, Gulbu; Casanova, Jean-Laurent; Lugo Reyes, Saul Oswaldo; Freeman, Alexandra F; Su, Helen C; Ma, Cindy S

2017-03-01

Dedicator of cytokinesis 8 (DOCK8) deficiency is a combined immunodeficiency caused by autosomal recessive loss-of-function mutations in DOCK8. This disorder is characterized by recurrent cutaneous infections, increased serum IgE levels, and severe atopic disease, including food-induced anaphylaxis. However, the contribution of defects in CD4 + T cells to disease pathogenesis in these patients has not been thoroughly investigated. We sought to investigate the phenotype and function of DOCK8-deficient CD4 + T cells to determine (1) intrinsic and extrinsic CD4 + T-cell defects and (2) how defects account for the clinical features of DOCK8 deficiency. We performed in-depth analysis of the CD4 + T-cell compartment of DOCK8-deficient patients. We enumerated subsets of CD4 + T helper cells and assessed cytokine production and transcription factor expression. Finally, we determined the levels of IgE specific for staple foods and house dust mite allergens in DOCK8-deficient patients and healthy control subjects. DOCK8-deficient memory CD4 + T cells were biased toward a T H 2 type, and this was at the expense of T H 1 and T H 17 cells. In vitro polarization of DOCK8-deficient naive CD4 + T cells revealed the T H 2 bias and T H 17 defect to be T-cell intrinsic. Examination of allergen-specific IgE revealed plasma IgE from DOCK8-deficient patients is directed against staple food antigens but not house dust mites. Investigations into the DOCK8-deficient CD4 + T cells provided an explanation for some of the clinical features of this disorder: the T H 2 bias is likely to contribute to atopic disease, whereas defects in T H 1 and T H 17 cells compromise antiviral and antifungal immunity, respectively, explaining the infectious susceptibility of DOCK8-deficient patients. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. All rights reserved.

Evaluation of Secretion Prediction Highlights Differing Approaches Needed for Oomycete and Fungal Effectors.

PubMed

Sperschneider, Jana; Williams, Angela H; Hane, James K; Singh, Karam B; Taylor, Jennifer M

2015-01-01

The steadily increasing number of sequenced fungal and oomycete genomes has enabled detailed studies of how these eukaryotic microbes infect plants and cause devastating losses in food crops. During infection, fungal and oomycete pathogens secrete effector molecules which manipulate host plant cell processes to the pathogen's advantage. Proteinaceous effectors are synthesized intracellularly and must be externalized to interact with host cells. Computational prediction of secreted proteins from genomic sequences is an important technique to narrow down the candidate effector repertoire for subsequent experimental validation. In this study, we benchmark secretion prediction tools on experimentally validated fungal and oomycete effectors. We observe that for a set of fungal SwissProt protein sequences, SignalP 4 and the neural network predictors of SignalP 3 (D-score) and SignalP 2 perform best. For effector prediction in particular, the use of a sensitive method can be desirable to obtain the most complete candidate effector set. We show that the neural network predictors of SignalP 2 and 3, as well as TargetP were the most sensitive tools for fungal effector secretion prediction, whereas the hidden Markov model predictors of SignalP 2 and 3 were the most sensitive tools for oomycete effectors. Thus, previous versions of SignalP retain value for oomycete effector prediction, as the current version, SignalP 4, was unable to reliably predict the signal peptide of the oomycete Crinkler effectors in the test set. Our assessment of subcellular localization predictors shows that cytoplasmic effectors are often predicted as not extracellular. This limits the reliability of secretion predictions that depend on these tools. We present our assessment with a view to informing future pathogenomics studies and suggest revised pipelines for secretion prediction to obtain optimal effector predictions in fungi and oomycetes.

CD4+ T Cell Response Correlates with Naturally Acquired Antibodies against Plasmodium vivax Tryptophan-Rich Antigens

PubMed Central

Zeeshan, Mohammad; Tyagi, Kriti

2015-01-01

Tryptophan-rich proteins play important biological functions for the Plasmodium parasite. Plasmodium vivax contains remarkably large numbers of such proteins belonging to the “Pv-fam-a” family that need to be characterized. Earlier, we reported the presence of memory T cells and naturally acquired antibodies against 15 of these proteins in P. vivax malaria-exposed individuals (M. Zeeshan, H. Bora, and Y. D. Sharma, J Infect Dis 207:175–185, 2013, http://dx.doi.org/10.1093/infdis/jis650). Here, we sought to characterize and ascertain the cross talk between effector responses of T and B cells in malarial patients against all Pv-fam-a family proteins. Therefore, we expressed the remaining 21 of these proteins in Escherichia coli and studied the humoral and cellular immune responses based on the same parameters used in our previous study. Naturally acquired IgG antibodies were detected against all 21 antigens in P. vivax patient sera (37.7 to 94.4% seropositivity). These antigens were able to activate the lymphocytes of P. vivax-exposed individuals, and the activated CD4+ T lymphocytes produced higher levels of Th1 (interleukin-2 [IL-2] and gamma interferon [IFN-γ]) and Th2 (IL-4 and IL-10) cytokines than the healthy controls, but the response was Th2 biased. The combined results of present and previous studies seem to suggest a striking link between induction of the CD4+ T cell response and naturally acquired antibodies against all 36 proteins of the Pv-fam-a family, the majority of them having conserved sequences in the parasite population. Further work is required to utilize this information to develop immunotherapeutic treatments for this disease. PMID:25733522

Fucosyltransferase Induction during Influenza Virus Infection Is Required for the Generation of Functional Memory CD4+ T Cells

PubMed Central

Carrette, Florent; Henriquez, Monique L.; Fujita, Yu

2018-01-01

T cells mediating influenza viral control are instructed in lymphoid and nonlymphoid tissues to differentiate into memory T cells that confer protective immunity. The mechanisms by which influenza virus–specific memory CD4+ T cells arise have been attributed to changes in transcription factors, cytokines and cytokine receptors, and metabolic programming. The molecules involved in these biosynthetic pathways, including proteins and lipids, are modified to varying degrees of glycosylation, fucosylation, sialation, and sulfation, which can alter their function. It is currently unknown how the glycome enzymatic machinery regulates CD4+ T cell effector and memory differentiation. In a murine model of influenza virus infection, we found that fucosyltransferase enzymatic activity was induced in effector and memory CD4+ T cells. Using CD4+ T cells deficient in the Fut4/7 enzymes that are expressed only in hematopoietic cells, we found decreased frequencies of effector cells with reduced expression of T-bet and NKG2A/C/E in the lungs during primary infection. Furthermore, Fut4/7−/− effector CD4+ T cells had reduced survival with no difference in proliferation or capacity for effector function. Although Fut4/7−/− CD4+ T cells seeded the memory pool after primary infection, they failed to form tissue-resident cells, were dysfunctional, and were unable to re-expand after secondary infection. Our findings highlight an important regulatory axis mediated by cell-intrinsic fucosyltransferase activity in CD4+ T cell effectors that ensure the development of functional memory CD4+ T cells. PMID:29491007

Human brucellosis is characterized by an intense Th1 profile associated with a defective monocyte function.

PubMed

Rodríguez-Zapata, Manuel; Matías, Marlene J; Prieto, Alfredo; Jonde, Marco A; Monserrat, Jorge; Sánchez, Lorenzo; Reyes, Eduardo; De la Hera, Antonio; Alvarez-Mon, Melchor

2010-07-01

In animal models, a defective Th1 response appears to be critical in the pathogenesis of brucellosis, but the Th1 response in human brucellosis patients remains partially undefined. Peripheral blood from 24 brucellosis patients was studied before and 45 days after antibiotherapy. Twenty-four sex- and age-matched healthy donors were analyzed in parallel. Significantly increased levels of interleukin 1beta (IL-1beta), IL-2, IL-4, IL-6, IL-12p40, gamma interferon (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha), but not of IL-10, in serum and/or significantly increased percentages of samples with detectable levels of these cytokines, measured by enzyme-linked immunosorbent assays (ELISA), were found for untreated brucellosis patients, but these levels were reduced and/or normalized after treatment. Flow cytometry studies showed that the intracytoplasmic expression of IFN-gamma, IL-2, and TNF-alpha, but not that of IL-4, by phorbol myristate-activated CD4(+) CD3(+) and CD8(+) CD3(+) T lymphocytes was significantly increased in untreated brucellosis patients and was also partially normalized after antibiotherapy. The percentage of phagocytic cells, the mean phagocytic activity per cell, and the phagocytic indices for monocytes at baseline were defective and had only partially reverted at follow-up. T lymphocytes from untreated brucellosis patients are activated in vivo and show Th1 cytokine production polarization, with strikingly high serum IFN-gamma levels. In spite of this Th1 environment, we found deficient effector phagocytic activity in peripheral blood monocytes.

Human Brucellosis Is Characterized by an Intense Th1 Profile Associated with a Defective Monocyte Function▿

PubMed Central

Rodríguez-Zapata, Manuel; Matías, Marlene J.; Prieto, Alfredo; Jonde, Marco A.; Monserrat, Jorge; Sánchez, Lorenzo; Reyes, Eduardo; De la Hera, Antonio; Alvarez-Mon, Melchor

2010-01-01

In animal models, a defective Th1 response appears to be critical in the pathogenesis of brucellosis, but the Th1 response in human brucellosis patients remains partially undefined. Peripheral blood from 24 brucellosis patients was studied before and 45 days after antibiotherapy. Twenty-four sex- and age-matched healthy donors were analyzed in parallel. Significantly increased levels of interleukin 1β (IL-1β), IL-2, IL-4, IL-6, IL-12p40, gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), but not of IL-10, in serum and/or significantly increased percentages of samples with detectable levels of these cytokines, measured by enzyme-linked immunosorbent assays (ELISA), were found for untreated brucellosis patients, but these levels were reduced and/or normalized after treatment. Flow cytometry studies showed that the intracytoplasmic expression of IFN-γ, IL-2, and TNF-α, but not that of IL-4, by phorbol myristate-activated CD4+ CD3+ and CD8+ CD3+ T lymphocytes was significantly increased in untreated brucellosis patients and was also partially normalized after antibiotherapy. The percentage of phagocytic cells, the mean phagocytic activity per cell, and the phagocytic indices for monocytes at baseline were defective and had only partially reverted at follow-up. T lymphocytes from untreated brucellosis patients are activated in vivo and show Th1 cytokine production polarization, with strikingly high serum IFN-γ levels. In spite of this Th1 environment, we found deficient effector phagocytic activity in peripheral blood monocytes. PMID:20404074

Direct anti-inflammatory effects of granulocyte colony-stimulating factor (G-CSF) on activation and functional properties of human T cell subpopulations in vitro.

PubMed

Malashchenko, Vladimir Vladimirovich; Meniailo, Maxsim Evgenievich; Shmarov, Viacheslav Anatolievich; Gazatova, Natalia Dinislamovna; Melashchenko, Olga Borisovna; Goncharov, Andrei Gennadievich; Seledtsova, Galina Victorovna; Seledtsov, Victor Ivanovich

2018-03-01

We investigated the direct effects of human granulocyte colony-stimulating factor (G-CSF) on functionality of human T-cell subsets. CD3 + T-lymphocytes were isolated from blood of healthy donors by positive magnetic separation. T cell activation with particles conjugated with antibodies (Abs) to human CD3, CD28 and CD2 molecules increased the proportion of cells expressing G-CSF receptor (G-CSFR, CD114) in all T cell subpopulations studied (CD45RA + /CD197 + naive T cells, CD45RA - /CD197 + central memory T cells, CD45RA - /CD197 - effector memory T cells and CD45RA + /CD197 - terminally differentiated effector T cells). Upon T-cell activation in vitro, G-CSF (10.0 ng/ml) significantly and specifically enhanced the proportion of CD114 + T cells in central memory CD4 + T cell compartment. A dilution series of G-CSF (range, 0.1-10.0 ng/ml) was tested, with no effect on the expression of CD25 (interleukin-2 receptor α-chain) on activated T cells. Meanwhile, G-CSF treatment enhanced the proportion of CD38 + T cells in CD4 + naïve T cell, effector memory T cell and terminally differentiated effector T cell subsets, as well as in CD4 - central memory T cells and terminally differentiated effector T cells. G-CSF did not affect IL-2 production by T cells; relatively low concentrations of G-CSF down-regulated INF-γ production, while high concentrations of this cytokine up-regulated IL-4 production in activated T cells. The data obtained suggests that G-CSF could play a significant role both in preventing the development of excessive and potentially damaging inflammatory reactivity, and in constraining the expansion of potentially cytodestructive T cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Ezh2 phosphorylation state determines its capacity to maintain CD8+ T memory precursors for antitumor immunity.

PubMed

He, Shan; Liu, Yongnian; Meng, Lijun; Sun, Hongxing; Wang, Ying; Ji, Yun; Purushe, Janaki; Chen, Pan; Li, Changhong; Madzo, Jozef; Issa, Jean-Pierre; Soboloff, Jonathan; Reshef, Ran; Moore, Bethany; Gattinoni, Luca; Zhang, Yi

2017-12-14

Memory T cells sustain effector T-cell production while self-renewing in reaction to persistent antigen; yet, excessive expansion reduces memory potential and impairs antitumor immunity. Epigenetic mechanisms are thought to be important for balancing effector and memory differentiation; however, the epigenetic regulator(s) underpinning this process remains unknown. Herein, we show that the histone methyltransferase Ezh2 controls CD8 + T memory precursor formation and antitumor activity. Ezh2 activates Id3 while silencing Id2, Prdm1 and Eomes, promoting the expansion of memory precursor cells and their differentiation into functional memory cells. Akt activation phosphorylates Ezh2 and decreases its control of these transcriptional programs, causing enhanced effector differentiation at the expense of T memory precursors. Engineering T cells with an Akt-insensitive Ezh2 mutant markedly improves their memory potential and capability of controlling tumor growth compared to transiently inhibiting Akt. These findings establish Akt-mediated phosphorylation of Ezh2 as a critical target to potentiate antitumor immunotherapeutic strategies.

Synthetic Retinoid AM80 Ameliorates Lung and Arthritic Autoimmune Responses by Inhibiting T Follicular Helper and Th17 Cell Responses.

PubMed

Naskar, Debdut; Teng, Fei; Felix, Krysta M; Bradley, C Pierce; Wu, Hsin-Jung Joyce

2017-03-01

Rheumatoid arthritis is an autoimmune disorder that affects the joints and other organs. Pulmonary complications contribute significantly to rheumatoid arthritis mortality. Retinoic acid and its synthetic compound AM80 play roles in immunoregulation but their effect on mucosal autoimmunity remains largely unknown. T follicular helper (Tfh) and Th17 cells are known to promote inflammation and autoantibody production. Using the K/BxN autoimmune arthritis model, we elucidate a novel mechanism whereby oral AM80 administration suppressed lung mucosa-associated Tfh and autoantibody responses by increasing the gut-homing α4β7 integrin expression on Tfh cells. This diverted Tfh cells from systemic (non-gut) inflamed sites such as the lung into the gut-associated lymphoid tissues, Peyer's patches, and thus reduced the systemic autoantibodies. AM80 also inhibited the lung Th17 response. AM80's effect in the lungs was readily applied to the joints as AM80 also inhibited Tfh and Th17 responses in the spleen, the major autoantibody producing site known to correlate with K/BxN arthritis severity. Finally, we used anti-β7 treatment as an alternative approach, demonstrating that manipulating T cell migration between the gut and systemic sites alters the systemic disease outcome. The β7 blockade prevented both Tfh and Th17 cells from entering the non-immunopathogenic site, the gut, and retained these T effector cells in the systemic sites, leading to augmented arthritis. These data suggest a dual beneficial effect of AM80, targeting both Tfh and Th17 cells, and warrant strict safety monitoring of gut-homing perturbing agents used in treating intestinal inflammation. Copyright © 2017 by The American Association of Immunologists, Inc.

The trifunctional antibody catumaxomab amplifies and shapes tumor-specific immunity when applied to gastric cancer patients in the adjuvant setting

PubMed Central

Atanackovic, Djordje; Reinhard, Henrike; Meyer, Sabrina; Spöck, Stefanie; Grob, Tobias; Luetkens, Tim; Yousef, Sara; Cao, Yanran; Hildebrandt, York; Templin, Julia; Bartels, Katrin; Lajmi, Nesrine; Stoiber, Heribert; Kröger, Nicolaus; Atz, Judith; Seimetz, Diane; Izbicki, Jakob R; Bokemeyer, Carsten

2013-01-01

Background: Patients with gastric cancer benefit from perioperative chemotherapy, however, treatment is toxic and many patients will relapse. The trifunctional antibody catumaxomab targets EpCAM on tumor cells, CD3 on T cells, and the Fcγ-receptor of antigen-presenting cells. While in Europe catumaxomab is approved for treating malignant ascites, it has not been investigated in the perioperative setting and its exact immunological mode of action is unclear. Methods: In our study, gastric cancer patients received neoadjuvant platinum-based chemotherapy, one intraoperative application of catumaxomab, and 4 postoperative doses of intraperitoneal catumaxomab. Immunomonitoring was performed in 6 patients before surgery, after completion of catumaxomab treatment, and one month later. Results: Intraperitoneal application of catumaxomab caused an increased expression of activation markers on the patients’ T cells. This was accompanied by a transient decrease in numbers of CXCR3+ effector T cells with a T-helper (Th)-1 phenotype in the peripheral blood. All patients evidenced pre-existing EpCAM-specific CD4+ and/or CD8+ T cells. While these cells transiently disappeared from the blood stream after intraperitoneal application of catumaxomab, we detected increased numbers of peripheral EpCAM-specific cells and a modified EpCAM-specific T-cell repertoire 4 weeks after completion of treatment. Finally, catumaxomab also amplified humoral immunity to tumor antigens other than EpCAM. Conclusions: Our findings suggest that catumaxomab exerts its clinical effects by (1) activating peripheral T cells, (2) redistributing effector T cells from the blood into peripheral tissues, (3) expanding and shaping of the pre-existing EpCAM-specific T-cell repertoire, and (4) spreading of anti-tumor immunity to different tumor antigens. PMID:23955093

Enhanced Requirement for TNFR2 in Graft Rejection Mediated by Low Affinity Memory CD8+ T Cells During Heterologous Immunity

PubMed Central

Krummey, Scott M.; Chen, Ching-Wen; Guasch, Sara A.; Liu, Danya; Wagener, Maylene; Larsen, Christian P; Ford, Mandy L.

2016-01-01

The affinity of a T cell receptor (TCR) binding to peptide:MHC profoundly impacts the phenotype and function of effector and memory cell differentiation. Little is known about the effect of low affinity priming on memory cell generation and function, which is particularly important in heterologous immunity, when microbe-specific T cells cross-react with allogeneic antigen and mediate graft rejection. We found that low affinity primed memory CD8+ T cells produced high levels of TNF ex vivo in response to heterologous rechallenge compared to high affinity primed memory T cells. Low affinity secondary effectors significantly upregulated TNFR2 on the cell surface and contained a higher frequency of TNFR2hi proliferating cells. Low affinity primed secondary effectors concurrently downregulated TNF production. Importantly, blockade of TNFR2 attenuated graft rejection in low but not high affinity primed animals. These data establish a functional connection between TNF signaling and TCR priming affinity and have implications for the immunomodulation of pathogenic T cell responses during transplantation. PMID:27481849

The lupus susceptibility gene Pbx1 regulates the balance between follicular helper T cell and regulatory T cell differentiation

PubMed Central

Choi, Seung-Chul; Hutchinson, Tarun E.; Titov, Anton A.; Seay, Howard R.; Li, Shiwu; Brusko, Todd M.; Croker, Byron P.; Salek-Ardakani, Shahram; Morel, Laurence

2016-01-01

Pbx1 controls chromatin accessibility to a large number of genes and is entirely conserved between mice and humans. The Pbx1-d dominant negative isoform is more frequent in the CD4+ T cells from lupus patients than from healthy controls. Pbx1-d is associated with the production of autoreactive T cells in mice carrying the Sle1a1 lupus susceptibility locus. Transgenic expression of Pbx1-d in CD4+ T cells reproduced the phenotypes of Sle1a1 mice, with increased inflammatory functions of CD4+ T cells and impaired regulatory T cell homeostasis. Pbx1-d Tg also expanded the number of follicular helper T cells in a cell-intrinsic and antigen-specific manner that was enhanced in recall responses, and resulted in TH1-biased antibodies. Moreover, Pbx1-d Tg CD4+ T cells upregulated the expression of miR-10a, miR-21 and miR-155, which have been implicated in Treg and TFH cell homeostasis. Our results suggest that Pbx1-d impacts lupus development by regulating effector T cell differentiation and promoting TFH cells at the expense of Treg cells. In addition, our results identify Pbx1 as a novel regulator of CD4+ T cell effector function. PMID:27296664

SLAP deficiency enhances number and function of regulatory T cells preventing chronic autoimmune arthritis in SKG mice.

PubMed

Peterson, Lisa K; Shaw, Laura A; Joetham, Anthony; Sakaguchi, Shimon; Gelfand, Erwin W; Dragone, Leonard L

2011-02-15

To test if manipulating TCR complex-mediated signaling (TCR signaling) could treat autoimmune disease, we generated the double SKG Src-like adapter protein (SLAP) knockout (DSSKO) mouse model. The SKG mutation in ZAP70 and SLAP have opposing functions on the regulation of TCR signaling. The combination of these two mutations alters TCR signaling in the context of a defined genetic background, uniform environmental conditions, and a well-characterized signaling disruption. In contrast to SKG mice, DSSKO mice do not develop zymosan-induced chronic autoimmune arthritis. This arthritis prevention is not due to significant alterations in thymocyte development or repertoire selection but instead enhanced numbers of regulatory T cells (Tregs) and decreased numbers of Th17 cells skewing the ratio of Tregs to autoreactive effector T cells. Treg depletion and/or functional blockade led to the development of arthritis in DSSKO mice. In vitro suppression of effector T cell proliferation was also enhanced, demonstrating that DSSKO mice have increased numbers of Tregs with increased function. Understanding how TCR signals influence development, expansion, and function of Tregs in DSSKO mice could advance our ability to manipulate Treg biology to treat ultimately autoimmune disease.

SLAP Deficiency Enhances Number and Function of Regulatory T Cells Preventing Chronic Autoimmune Arthritis in SKG Mice

PubMed Central

Peterson, Lisa K.; Shaw, Laura A.; Joetham, Anthony; Sakaguchi, Shimon; Gelfand, Erwin W.; Dragone, Leonard L.

2011-01-01

To test if manipulating TCR complex-mediated signaling (TCR signaling) could treat autoimmune disease, we generated the double SKG Src-like adapter protein (SLAP) knockout (DSSKO) mouse model. The SKG mutation in ZAP70 and SLAP have opposing functions on the regulation of TCR signaling. The combination of these two mutations alters TCR signaling in the context of a defined genetic background, uniform environmental conditions, and a well-characterized signaling disruption. In contrast to SKG mice, DSSKO mice do not develop zymosan-induced chronic autoimmune arthritis. This arthritis prevention is not due to significant alterations in thymocyte development or repertoire selection but instead enhanced numbers of regulatory T cells (Tregs) and decreased numbers of Th17 cells skewing the ratio of Tregs to autoreactive effector T cells. Treg depletion and/or functional blockade led to the development of arthritis in DSSKO mice. In vitro suppression of effector T cell proliferation was also enhanced, demonstrating that DSSKO mice have increased numbers of Tregs with increased function. Understanding how TCR signals influence development, expansion, and function of Tregs in DSSKO mice could advance our ability to manipulate Treg biology to treat ultimately autoimmune disease. PMID:21248251

The Xanthomonas euvesicatoria type III effector XopAU is an active protein kinase that manipulates plant MAP kinase signaling.

PubMed

Teper, Doron; Girija, Anil Madhusoodana; Bosis, Eran; Popov, Georgy; Savidor, Alon; Sessa, Guido

2018-01-01

The Gram-negative bacterium Xanthomonas euvesicatoria (Xe) is the causal agent of bacterial spot disease of pepper and tomato. Xe delivers effector proteins into host cells through the type III secretion system to promote disease. Here, we show that the Xe effector XopAU, which is conserved in numerous Xanthomonas species, is a catalytically active protein kinase and contributes to the development of disease symptoms in pepper plants. Agrobacterium-mediated expression of XopAU in host and non-host plants activated typical defense responses, including MAP kinase phosphorylation, accumulation of pathogenesis-related (PR) proteins and elicitation of cell death, that were dependent on the kinase activity of the effector. XopAU-mediated cell death was not dependent on early signaling components of effector-triggered immunity and was also observed when the effector was delivered into pepper leaves by Xanthomonas campestris pv. campestris, but not by Xe. Protein-protein interaction studies in yeast and in planta revealed that XopAU physically interacts with components of plant immunity-associated MAP kinase cascades. Remarkably, XopAU directly phosphorylated MKK2 in vitro and enhanced its phosphorylation at multiple sites in planta. Consistent with the notion that MKK2 is a target of XopAU, silencing of the MKK2 homolog or overexpression of the catalytically inactive mutant MKK2K99R in N. benthamiana plants reduced XopAU-mediated cell death and MAPK phosphorylation. Furthermore, yeast co-expressing XopAU and MKK2 displayed reduced growth and this phenotype was dependent on the kinase activity of both proteins. Together, our results support the conclusion that XopAU contributes to Xe disease symptoms in pepper plants and manipulates host MAPK signaling through phosphorylation and activation of MKK2.

Bacterial effectors target the plant cell nucleus to subvert host transcription.

PubMed

Canonne, Joanne; Rivas, Susana

2012-02-01

In order to promote virulence, Gram-negative bacteria have evolved the ability to inject so-called type III effector proteins into host cells. The plant cell nucleus appears to be a subcellular compartment repeatedly targeted by bacterial effectors. In agreement with this observation, mounting evidence suggests that manipulation of host transcription is a major strategy developed by bacteria to counteract plant defense responses. It has been suggested that bacterial effectors may adopt at least three alternative, although not mutually exclusive, strategies to subvert host transcription. T3Es may (1) act as transcription factors that directly activate transcription in host cells, (2) affect histone packing and chromatin configuration, and/or (3) target host transcription factor activity. Here, we provide an overview on how all these strategies may lead to host transcriptional re-programming and, as a result, to improved bacterial multiplication inside plant cells.

Acute virus control mediated by licensed NK cells sets primary CD8+ T cell dependence on CD27 costimulation1,2,3

PubMed Central

Teoh, Jeffrey J.; Gamache, Awndre E.; Gillespie, Alyssa L.; Stadnisky, Michael D.; Yagita, Hideo; Bullock, Timothy N.J.; Brown, Michael G.

2016-01-01

Natural killer (NK) cells represent a critical first-line of immune defense against a bevy of viral pathogens, and infection can provoke them to mediate both supportive and suppressive effects on virus-specific adaptive immunity. In mice expressing MHC I Dk, a major MCMV resistance factor and self-ligand of the inhibitory Ly49G2 (G2) receptor, licensed G2+ NK cells provide essential host resistance against murine (M)CMV infection. Additionally G2+ NK cell responses to MCMV increase the rate and extent of dendritic cell (DC) recovery, as well as early priming of CD8+ T-cell effectors in response to MCMV. However, relatively little is known about the NK-cell effect on co-stimulatory ligand patterns displayed by DCs, or ensuing effector and memory T-cell responses. Here we found that CD27-dependent CD8+ T-cell priming and differentiation is shaped by the efficiency of NK responses to virus infection. Surprisingly, differences in specific NK responses to MCMV in Dk-disparate mice failed to distinguish early DC co-stimulatory patterns. Nonetheless, while CD27 deficiency did not impede licensed NK-mediated resistance, both CD70 and CD27 were required to efficiently prime and regulate effector CD8+ T-cell differentiation in response to MCMV, which eventually resulted in biased memory T-cell precursor formation in Dk mice. In contrast, CD8+ T-cells accrued more slowly in non-Dk mice, and eventually differentiated into terminal effector cells regardless of CD27 stimulation. Disparity in this requirement for CD27 signaling indicates that specific virus control mediated by NK cells can shape DC co-stimulatory signals needed to prime CD8+ T cells and eventual T-cell fate decisions. PMID:27798162

The Shigella flexneri OspB effector: an early immunomodulator.

PubMed

Ambrosi, Cecilia; Pompili, Monica; Scribano, Daniela; Limongi, Dolores; Petrucca, Andrea; Cannavacciuolo, Sonia; Schippa, Serena; Zagaglia, Carlo; Grossi, Milena; Nicoletti, Mauro

2015-01-01

Through the action of the type three secretion system (T3SS) Shigella flexneri delivers several effectors into host cells to promote cellular invasion, multiplication and to exploit host-cell signaling pathways to modulate the host innate immune response. Although much progress has been made in the understanding of many type III effectors, the molecular and cellular mechanism of the OspB effector is still poorly characterized. In this study we present new evidence that better elucidates the role of OspB as pro-inflammatory factor at very early stages of infection. Indeed, we demonstrate that, during the first hour of infection, OspB is required for full activation of ERK1/2 and p38 MAPKs and the cytosolic phospholipase A(2) (cPLA(2)). Activation of cPLA(2) ultimately leads to the production and secretion of PMN chemoattractant metabolite(s) uncoupled with release of IL-8. Moreover, we also present evidence that OspB is required for the development of the full and promptly inflammatory reaction characteristic of S. flexneri wild-type infection in vivo. Based on OspB and OspF similarity (both effectors share similar transcription regulation, temporal secretion into host cells and nuclear localization) we hypothesized that OspB and OspF effectors may form a pair aimed at modulating the host cell response throughout the infection process, with opposite effects. A model is presented to illustrate how OspB activity would promote S. flexneri invasion and bacterial dissemination at early critical phases of infection. Copyright © 2014 Elsevier GmbH. All rights reserved.

Cutting edge: control of Mycobacterium tuberculosis infection by a subset of lung parenchyma-homing CD4 T cells.

PubMed

Sakai, Shunsuke; Kauffman, Keith D; Schenkel, Jason M; McBerry, Cortez C; Mayer-Barber, Katrin D; Masopust, David; Barber, Daniel L

2014-04-01

Th1 cells are critical for containment of Mycobacterium tuberculosis infection, but little else is known about the properties of protective CD4 T cell responses. In this study, we show that the pulmonary Th1 response against M. tuberculosis is composed of two populations that are either CXCR3(hi) and localize to lung parenchyma or are CX3CR1(hi)KLRG1(hi) and are retained within lung blood vasculature. M. tuberculosis-specific parenchymal CD4 T cells migrate rapidly back into the lung parenchyma upon adoptive transfer, whereas the intravascular effectors produce the highest levels of IFN-γ in vivo. Importantly, parenchymal T cells displayed greater control of infection compared with the intravascular counterparts upon transfer into susceptible T cell-deficient hosts. Thus, we identified a subset of naturally generated M. tuberculosis-specific CD4 T cells with enhanced protective capacity and showed that control of M. tuberculosis correlates with the ability of CD4 T cells to efficiently enter the lung parenchyma rather than produce high levels of IFN-γ.

Interleukin-17A-producing T lymphocytes in chronic active Epstein-Barr virus infection.

PubMed

Ohta, Rieko; Imai, Masaki; Kawada, Jun-ichi; Kimura, Hiroshi; Ito, Yoshinori

2013-02-01

T helper (Th) 17 cells are reportedly effector T cells that produce interleukin (IL)-17A and play a significant role in the development of autoimmune diseases and immune responses for antimicrobial host defense. Production of IL-17A in chronic active Epstein-Barr virus infection (CAEBV) was studied to investigate its contribution to pathogenesis of this disease. Significantly more IL-17A-producing cells were detected in the peripheral blood of CAEBV patients than in that of healthy controls, although a significant difference in serum IL-17A production was not confirmed. Of the IL-17A-producing cells, 91.8% were cluster of differentiation (CD)4-positive Th17 cells. Moreover, there were significantly more IL-17A-producing cells among CD4(+) cells in peripheral blood of CAEBV patients than in that of controls (1.97 ± 0.69% vs. 1.09 ± 0.53%, P = 0.0073). These data suggest that IL-17A-producing cells may influence the pathophysiology of CAEBV. © 2012 The Societies and Wiley Publishing Asia Pty Ltd.

IL-27 promotes IL-10 production by effector Th1 CD4+ T cells; a critical mechanism for protection from severe immunopathology during malaria infection1

PubMed Central

Freitas do Rosário, Ana Paula; Lamb, Tracey; Spence, Philip; Stephens, Robin; Lang, Agathe; Roers, Axel; Muller, Werner; O’Garra, Anne; Langhorne, Jean

2012-01-01

Infection with the malaria parasite, Plasmodium, is characterized by excessive inflammation. The establishment of a precise balance between the pro- and anti-inflammatory responses is critical to guarantee control of the parasite and survival of the host. Interleukin (IL)-10, a key regulatory cytokine produced by many cells of the immune system, has been shown to protect mice against pathology during acute Plasmodium chabaudi chabaudi AS model of malaria. However, the critical cellular source of IL-10 is still unknown. Here, we demonstrate that T cell-derived IL-10 is necessary for the control of pathology during acute malaria, as mice bearing specific deletion of Il10 in T cells fully reproduce the phenotype observed in Il10−/− mice, with significant weight loss, drop in temperature and increased mortality. Furthermore, we show that IFN-γ+ Th1 cells are the main producers of IL-10 throughout acute infection, expressing high levels of CD44 and ICOS and low levels of CD127. Although Foxp3+ regulatory CD4+ T cells produce IL-10 during infection, highly activated IFN-γ+ Th1 cells were shown to be the essential and sufficient source of IL-10 to guarantee protection against severe immune-mediated pathology. Finally, in this model of malaria we demonstrate that the generation of protective IL10+IFN-γ+ Th1 cells is dependent on IL-27 signaling, and independent of IL-21. PMID:22205023

Visualization of T Cell-Regulated Monocyte Clusters Mediating Keratinocyte Death in Acquired Cutaneous Immunity.

PubMed

Liu, Zheng; Yang, Fei; Zheng, Hao; Fan, Zhan; Qiao, Sha; Liu, Lei; Tao, Juan; Luo, Qingming; Zhang, Zhihong

2018-06-01

It remains unclear how monocytes are mobilized to amplify inflammatory reactions in T cell-mediated adaptive immunity. Here, we investigate dynamic cellular events in the cascade of inflammatory responses through intravital imaging of a multicolor-labeled murine contact hypersensitivity model. We found that monocytes formed clusters around hair follicles in the contact hypersensitivity model. In this process, effector T cells encountered dendritic cells under regions of monocyte clusters and secreted IFN-γ, which mobilizes CCR2-dependent monocyte interstitial migration and CXCR2-dependent monocyte cluster formation. We showed that hair follicles shaped the inflammatory microenvironment for communication among the monocytes, keratinocytes, and effector T cells. After disrupting the T cell-mobilized monocyte clusters through CXCR2 antagonization, monocyte activation and keratinocyte apoptosis were significantly inhibited. Our study provides a new perspective on effector T cell-regulated monocyte behavior, which amplifies the inflammatory reaction in acquired cutaneous immunity. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

A novel, disruptive vaccination technology: self-adjuvanted RNActive(®) vaccines.

PubMed

Kallen, Karl-Josef; Heidenreich, Regina; Schnee, Margit; Petsch, Benjamin; Schlake, Thomas; Thess, Andreas; Baumhof, Patrick; Scheel, Birgit; Koch, Sven D; Fotin-Mleczek, Mariola

2013-10-01

Nucleotide based vaccines represent an enticing, novel approach to vaccination. We have developed a novel immunization technology, RNActive(®) vaccines, that have two important characteristics: mRNA molecules are used whose protein expression capacity has been enhanced by 4 to 5 orders of magnitude by modifications of the nucleotide sequence with the naturally occurring nucleotides A (adenosine), G (guanosine), C (cytosine), U (uridine) that do not affect the primary amino acid sequence. Second, they are complexed with protamine and thus activate the immune system by involvement of toll-like receptor (TLR) 7. Essentially, this bestows self-adjuvant activity on RNActive(®) vaccines. RNActive(®) vaccines induce strong, balanced immune responses comprising humoral and cellular responses, effector and memory responses as well as activation of important subpopulations of immune cells, such as Th1 and Th2 cells. Pre-germinal center and germinal center B cells were detected in human patients upon vaccination. RNActive(®) vaccines successfully protect against lethal challenges with a variety of different influenza strains in preclinical models. Anti-tumor activity was observed preclinically under therapeutic as well as prophylactic conditions. Initial clinical experiences suggest that the preclinical immunogenicity of RNActive(®) could be successfully translated to humans.

EOSINOPHILS: MULTIFACETED BIOLOGIC PROPERTIES AND ROLES IN HEALTH AND DISEASE

PubMed Central

Kita, Hirohito

2011-01-01

Summary Eosinophils are leukocytes resident in mucosal tissues. During Th2-type inflammation, eosinophils are recruited from bone marrow and blood to the sites of immune response. While eosinophils have been considered end-stage cells involved in host protection against parasite infection and immunopathology in hypersensitivity disease, recent studies changed this perspective. Eosinophils are now considered multifunctional leukocytes involved in tissue homeostasis, modulation of adaptive immune responses, and innate immunity to certain microbes. Eosinophils are capable of producing immunoregulatory cytokines and are actively involved in regulation of Th2-type immune responses. However, such new information does not preclude earlier observations showing that eosinophils, in particular human eosinophils, are also effector cells with pro-inflammatory and destructive capabilities. Eosinophils with activation phenotypes are observed in biological specimens from patients with disease, and deposition of eosinophil products is readily seen in the affected tissues from these patients. Therefore, it would be reasonable to consider the eosinophil a multifaceted leukocyte that contributes to various physiological and pathological processes depending on their location and activation status. This review summarizes the emerging concept of the multifaceted immunobiology of eosinophils and discusses the roles of eosinophils in health and disease and the challenges and perspectives in the field. PMID:21682744

Immune Checkpoint Blockade for Breast Cancer.

PubMed

Swoboda, April; Nanda, Rita

An effective antitumor immune response requires interaction between cells of the adaptive and innate immune system. Three key elements are required: generation of activated tumor-directed T cells, infiltration of activated T cells into the tumor microenvironment, and killing of tumor cells by activated T cells. Tumor immune evasion can occur as a result of the disruption of each of these three key T cell activities, resulting in three distinct cancer-immune phenotypes. The immune inflamed phenotype, characterized by the presence of a robust tumor immune infiltrate, suggests impaired activated T cell killing of tumor cells related to the presence of inhibitory factors. Programmed death receptor-1 (PD-1) is an inhibitory transmembrane protein expressed on T cells, B cells, and NK cells. The interaction between PD-1 and its ligands (PD-L1/L2) functions as an immune checkpoint against unrestrained cytotoxic T effector cell activity-it promotes peripheral T effector cell exhaustion and conversion of T effector cells to immunosuppressive T regulatory (Treg) cells. Immune checkpoint inhibitors, which block the PD-1/PD-L1 axis and reactivate cytotoxic T effector cell function, are actively being investigated for the treatment of breast cancer.

Cytotoxic effector functions of T cells are not required for protective immunity against fatal Rickettsia typhi infection in a murine model of infection: Role of TH1 and TH17 cytokines in protection and pathology

PubMed Central

Rauch, Jessica; Papp, Stefanie; Kuehl, Svenja; Richardt, Ulricke; Fleischer, Bernhard; Osterloh, Anke

2017-01-01

Endemic typhus caused by Rickettsia (R.) typhi is an emerging febrile disease that can be fatal due to multiple organ pathology. Here we analyzed the requirements for protection against R. typhi by T cells in the CB17 SCID model of infection. BALB/c wild-type mice generate CD4+ TH1 and cytotoxic CD8+ T cells both of which are sporadically reactivated in persistent infection. Either adoptively transferred CD8+ or CD4+ T cells protected R. typhi-infected CB17 SCID mice from death and provided long-term control. CD8+ T cells lacking either IFNγ or Perforin were still protective, demonstrating that the cytotoxic function of CD8+ T cells is not essential for protection. Immune wild-type CD4+ T cells produced high amounts of IFNγ, induced the release of nitric oxide in R. typhi-infected macrophages and inhibited bacterial growth in vitro via IFNγ and TNFα. However, adoptive transfer of CD4+IFNγ-/- T cells still protected 30–90% of R. typhi-infected CB17 SCID mice. These cells acquired a TH17 phenotype, producing high amounts of IL-17A and IL-22 in addition to TNFα, and inhibited bacterial growth in vitro. Surprisingly, the neutralization of either TNFα or IL-17A in CD4+IFNγ-/- T cell recipient mice did not alter bacterial elimination by these cells in vivo, led to faster recovery and enhanced survival compared to isotype-treated animals. Thus, collectively these data show that although CD4+ TH1 cells are clearly efficient in protection against R. typhi, CD4+ TH17 cells are similarly protective if the harmful effects of combined production of TNFα and IL-17A can be inhibited. PMID:28222146

Live Attenuated Leishmania donovani Centrin Knock Out Parasites Generate Non-inferior Protective Immune Response in Aged Mice against Visceral Leishmaniasis.

PubMed

Bhattacharya, Parna; Dey, Ranadhir; Dagur, Pradeep K; Joshi, Amritanshu B; Ismail, Nevien; Gannavaram, Sreenivas; Debrabant, Alain; Akue, Adovi D; KuKuruga, Mark A; Selvapandiyan, Angamuthu; McCoy, John Philip; Nakhasi, Hira L

2016-08-01

Visceral leishmaniasis (VL) caused by the protozoan parasite Leishmania donovani causes severe disease. Age appears to be critical in determining the clinical outcome of VL and at present there is no effective vaccine available against VL for any age group. Previously, we showed that genetically modified live attenuated L. donovani parasites (LdCen-/-) induced a strong protective innate and adaptive immune response in young mice. In this study we analyzed LdCen-/- parasite mediated modulation of innate and adaptive immune response in aged mice (18 months) and compared to young (2 months) mice. Analysis of innate immune response in bone marrow derived dendritic cells (BMDCs) from both young and aged mice upon infection with LdCen-/- parasites, showed significant enhancement of innate effector responses, which consequently augmented CD4+ Th1 cell effector function compared to LdWT infected BMDCs in vitro. Similarly, parasitized splenic dendritic cells from LdCen-/- infected young and aged mice also revealed induction of proinflammatory cytokines (IL-12, IL-6, IFN-γ and TNF) and subsequent down regulation of anti-inflammatory cytokine (IL-10) genes compared to LdWT infected mice. We also evaluated in vivo protection of the LdCen-/- immunized young and aged mice against virulent L. donovani challenge. Immunization with LdCen-/- induced higher IgG2a antibodies, lymphoproliferative response, pro- and anti-inflammatory cytokine responses and stimulated splenocytes for heightened leishmanicidal activity associated with nitric oxide production in young and aged mice. Furthermore, upon virulent L. donovani challenge, LdCen-/- immunized mice from both age groups displayed multifunctional Th1-type CD4 and cytotoxic CD8 T cells correlating to a significantly reduced parasite burden in the spleen and liver compared to naïve mice. It is interesting to note that even though there was no difference in the LdCen-/- induced innate response in dendritic cells between aged and young mice; the adaptive response specifically in terms of T cell and B cell activation in aged animals was reduced compared to young mice which correlated with less protection in old mice compared to young mice. Taken together, LdCen-/- immunization induced a significant but diminished host protective response in aged mice after challenge with virulent L. donovani parasites compared to young mice.

Live Attenuated Leishmania donovani Centrin Knock Out Parasites Generate Non-inferior Protective Immune Response in Aged Mice against Visceral Leishmaniasis

PubMed Central

Bhattacharya, Parna; Dey, Ranadhir; Dagur, Pradeep K.; Joshi, Amritanshu B.; Ismail, Nevien; Gannavaram, Sreenivas; Debrabant, Alain; Akue, Adovi D.; KuKuruga, Mark A.; Selvapandiyan, Angamuthu; McCoy, John Philip; Nakhasi, Hira L.

2016-01-01

Background Visceral leishmaniasis (VL) caused by the protozoan parasite Leishmania donovani causes severe disease. Age appears to be critical in determining the clinical outcome of VL and at present there is no effective vaccine available against VL for any age group. Previously, we showed that genetically modified live attenuated L. donovani parasites (LdCen-/-) induced a strong protective innate and adaptive immune response in young mice. In this study we analyzed LdCen-/- parasite mediated modulation of innate and adaptive immune response in aged mice (18 months) and compared to young (2 months) mice. Methodology Analysis of innate immune response in bone marrow derived dendritic cells (BMDCs) from both young and aged mice upon infection with LdCen-/- parasites, showed significant enhancement of innate effector responses, which consequently augmented CD4+ Th1 cell effector function compared to LdWT infected BMDCs in vitro. Similarly, parasitized splenic dendritic cells from LdCen-/- infected young and aged mice also revealed induction of proinflammatory cytokines (IL-12, IL-6, IFN-γ and TNF) and subsequent down regulation of anti-inflammatory cytokine (IL-10) genes compared to LdWT infected mice. We also evaluated in vivo protection of the LdCen-/- immunized young and aged mice against virulent L. donovani challenge. Immunization with LdCen-/- induced higher IgG2a antibodies, lymphoproliferative response, pro- and anti-inflammatory cytokine responses and stimulated splenocytes for heightened leishmanicidal activity associated with nitric oxide production in young and aged mice. Furthermore, upon virulent L. donovani challenge, LdCen-/- immunized mice from both age groups displayed multifunctional Th1-type CD4 and cytotoxic CD8 T cells correlating to a significantly reduced parasite burden in the spleen and liver compared to naïve mice. It is interesting to note that even though there was no difference in the LdCen-/- induced innate response in dendritic cells between aged and young mice; the adaptive response specifically in terms of T cell and B cell activation in aged animals was reduced compared to young mice which correlated with less protection in old mice compared to young mice. Conclusions Taken together, LdCen-/- immunization induced a significant but diminished host protective response in aged mice after challenge with virulent L. donovani parasites compared to young mice. PMID:27580076

Caveolin-mediated endocytosis of the Chlamydia M278 outer membrane peptide encapsulated in poly(lactic acid)-Poly(ethylene glycol) nanoparticles by mouse primary dendritic cells enhances specific immune effectors mediated by MHC class II and CD4+ T cells.

PubMed

Dixit, Saurabh; Sahu, Rajnish; Verma, Richa; Duncan, Skyla; Giambartolomei, Guillermo H; Singh, Shree R; Dennis, Vida A

2018-03-01

We previously developed a Chlamydia trachomatis nanovaccine (PPM) by encapsulating a chlamydial M278 peptide within poly(lactic acid)-poly(ethylene glycol) biodegradable nanoparticles that immunopotentiated Chlamydia-specific immune effector responses in mice. Herein, we investigated the mechanistic interactions of PPM with mouse bone marrow-derived dendritic cells (DCs) for its uptake, trafficking, and T cell activation. Our results reveal that PPM triggered enhanced expression of effector cytokines and chemokines, surface activation markers (Cd1d2, Fcgr1), pathogen-sensing receptors (TLR2, Nod1), co-stimulatory (CD40, CD80, CD86) and MHC class I and II molecules. Co-culturing of PPM-primed DCs with T cells from C. muridarum vaccinated mice yielded an increase in Chlamydia-specific immune effector responses including CD3 + lymphoproliferation, CD3 + CD4 + IFN-γ-secreting cells along with CD3 + CD4 + memory (CD44 high and CD62L high ) and effector (CD44 high and CD62L low ) phenotypes. Intracellular trafficking analyses revealed an intense expression and colocalization of PPM predominantly in endosomes. PPM also upregulated the transcriptional and protein expression of the endocytic mediator, caveolin-1 in DCs. More importantly, the specific inhibition of caveolin-1 led to decreased expression of PPM-induced cytokines and co-stimulatory molecules. Our investigation shows that PPM provided enhancement of uptake, probably by exploiting the caveolin-mediated endocytosis pathway, endosomal processing, and MHC II presentation to immunopotentiate Chlamydia-specific immune effector responses mediated by CD4 + T cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Secreted Effector Protein of Ustilago maydis Guides Maize Leaf Cells to Form Tumors

PubMed Central

Redkar, Amey; Hoser, Rafal; Schilling, Lena; Zechmann, Bernd; Krzymowska, Magdalena; Walbot, Virginia; Doehlemann, Gunther

2015-01-01

The biotrophic smut fungus Ustilago maydis infects all aerial organs of maize (Zea mays) and induces tumors in the plant tissues. U. maydis deploys many effector proteins to manipulate its host. Previously, deletion analysis demonstrated that several effectors have important functions in inducing tumor expansion specifically in maize leaves. Here, we present the functional characterization of the effector See1 (Seedling efficient effector1). See1 is required for the reactivation of plant DNA synthesis, which is crucial for tumor progression in leaf cells. By contrast, See1 does not affect tumor formation in immature tassel floral tissues, where maize cell proliferation occurs independent of fungal infection. See1 interacts with a maize homolog of SGT1 (Suppressor of G2 allele of skp1), a factor acting in cell cycle progression in yeast (Saccharomyces cerevisiae) and an important component of plant and human innate immunity. See1 interferes with the MAPK-triggered phosphorylation of maize SGT1 at a monocot-specific phosphorylation site. We propose that See1 interferes with SGT1 activity, resulting in both modulation of immune responses and reactivation of DNA synthesis in leaf cells. This identifies See1 as a fungal effector that directly and specifically contributes to the formation of leaf tumors in maize. PMID:25888589

T cells expanded in presence of IL-15 exhibit increased antioxidant capacity and innate effector molecules

PubMed Central

Kaur, Navtej; Naga, Osama S.; Norell, Håkan; Al-Khami, Amir A.; Scheffel, Matthew J.; Chakraborty, Nitya G.; Voelkel-Johnson, Christina; Mukherji, Bijay; Mehrotra, Shikhar

2011-01-01

Persistence of effector cytotoxic T lymphocytes (CTLs) during an immunological response is critical for successfully controlling a viral infection or tumor growth. Various cytokines are known to play an important part in regulating the immune response. The IL-2 family of cytokines that includes IL-2 and IL-15 are known to function as growth and survival factors for antigen-experienced T cells. IL-2 and IL-15 possess similar properties, including the ability to induce T cell proliferation. Whereas long term IL-2 exposure has been shown to promote apoptosis and limit CD8+ memory T cell survival and proliferation, it is widely believed that IL-15 can inhibit apoptosis and helps maintain a memory CD8+ T-cell population. However, mechanisms for superior outcomes for IL-15 as compared to IL-2 are still under investigation. Our data shows that human T cells cultured in the presence of IL-15 exhibit increased expression of anti-oxidant molecules Glutathione reductase (GSR), Thioredoxin reductase 1 (TXNDR1), Peroxiredoxin (PRDX), Superoxide dismutase (SOD). An increased expression of cell-surface thiols, intracellular glutathione, and thioredoxins was also noted in IL-15 cultured T cells. Additionally, IL-15 cultured T cells also showed an increase in cytolytic effector molecules. Apart from increased level of Granzyme A and Granzyme B, IL-15 cultured T cells exhibit increased accumulation of reactive oxygen (ROS) and reactive nitrogen (RNS) species as compared to IL-2 cultured T cells. Overall, this study suggests that T cells cultured in IL-15 show increase persistence not only due to increased anti-apoptotic proteins but also due to increased anti-oxidant levels, which is further complimented by increased cytolytic effector functions. PMID:21602054

Anti-GD2 mAb and Vorinostat synergize in the treatment of neuroblastoma.

PubMed

Kroesen, Michiel; Büll, Christian; Gielen, Paul R; Brok, Ingrid C; Armandari, Inna; Wassink, Melissa; Looman, Maaike W G; Boon, Louis; den Brok, Martijn H; Hoogerbrugge, Peter M; Adema, Gosse J

2016-06-01

Neuroblastoma (NBL) is a childhood malignancy of the sympathetic nervous system. For high-risk NBL patients, the mortality rate is still over 50%, despite intensive multimodal treatment. Anti-GD2 monoclonal antibody (mAB) in combination with systemic cytokine immunotherapy has shown clinical efficacy in high-risk NBL patients. Targeted therapy using histone deacetylase inhibitors (HDACi) is currently being explored in cancer treatment and already shows promising results. Using our recently developed transplantable TH-MYCN NBL model, we here report that the HDAC inhibitor Vorinostat synergizes with anti-GD2 mAb therapy in reducing NBL tumor growth. Further mechanistic studies uncovered multiple mechanisms for the observed synergy, including Vorinostat-induced specific NBL cell death and upregulation of the tumor antigen GD2 on the cell surface of surviving NBL cells. Moreover, Vorinostat created a permissive tumor microenvironment (TME) for tumor-directed mAb therapy by increasing macrophage effector cells expressing high levels of Fc-receptors (FcR) and decreasing the number and function of myeloid-derived suppressor cells (MDSC). Collectively, these data imply further testing of other epigenetic modulators with immunotherapy and provide a strong basis for clinical testing of anti-GD2 plus Vorinostat combination therapy in NBL patients.

Identification of legionella effectors using bioinformatic approaches.

PubMed

Segal, Gil

2013-01-01

Legionella pneumophila the causative agent of Legionnaires' disease, actively manipulates host cell processes to establish a replication niche inside host cells. The establishment of its replication niche requires a functional Icm/Dot type IV secretion system which translocates about 300 effector proteins into host cells during infection. Many of these effectors were first identified as effector candidates by several bioinformatic approaches, and these predicted effectors were later examined experimentally for translocation and a large number of which were validated as effector proteins. Here, I summarized the bioinformatic approaches that were used to identify these effectors.

The immune system and skin cancer.

PubMed

Yu, Sherry H; Bordeaux, Jeremy S; Baron, Elma D

2014-01-01

Carcinogenesis involves multiple mechanisms that disturb genomic integrity and encourage abnormal proliferation. The immune system plays an integral role in maintaining homeostasis and these mechanisms may arrest or enhance dysplasia. There exists a large body of evidence from organ transplantation literature supporting the significance of the immune suppression in the development of skin cancer. Nonmelanoma skin cancers are the most frequent neoplasms after organ transplantation, with organ transplant recipients having a 65-fold increase in squamous cell carcinoma incidence and 10-fold increase in basal cell carcinoma incidence. Similarly, UV-radiation (UVR) induced immunosuppression is correlated with the development of cutaneous malignancies in a dose-dependent manner. This was first shown several decades ago by Margaret Kripke, when transplanted tumors were rejected in mice with competent immune systems, but grew unchecked in immunosuppressed specimens. After UV exposure, chromophores initiate a cascade that leads to immunosuppression via derangement of Langerhans cells' antigen-presenting capacity. UV-irradiated Langerhans cells present antigens to Th2 cells, but fail to stimulate Th1 cells. A subset of T regulatory cells, specific for the antigen encountered after UVR, is also stimulated to proliferate. In general UV irradiation leads to a greater number of T regulatory cells and fewer effector T cells in the skin, shiftingthe balance from T-cell-mediated immunity to immunosuppression. These regulatory cells have the phenotype CD4+, CD25+, Foxp3+, CTLA-4+. These and many other changes in local immunity lead to a suppressed immune state, which allow for skin cancer development.

B-Glucan exacerbates allergic asthma independent of fungal ...

EPA Pesticide Factsheets

BackgroundAllergic sensitization to fungi has been associated with asthma severity. As a result, it has been largely assumed that the contribution of fungi to allergic disease is mediated through their potent antigenicity.ObjectiveWe sought to determine the mechanism by which fungi affect asthma development and severity.MethodsWe integrated epidemiologic and experimental asthma models to explore the effect of fungal exposure on asthma development and severity.ResultsWe report that fungal exposure enhances allergen-driven TH2 responses, promoting severe allergic asthma. This effect is independent of fungal sensitization and can be reconstituted with β-glucan and abrogated by neutralization of IL-17A. Furthermore, this severe asthma is resistant to steroids and characterized by mixed TH2 and TH17 responses, including IL-13+IL-17+CD4+ double-producing effector T cells. Steroid resistance is dependent on fungus-induced TH17 responses because steroid sensitivity was restored in IL-17rc−/− mice. Similarly, in children with asthma, fungal exposure was associated with increased serum IL-17A levels and asthma severity.ConclusionOur data demonstrate that fungi are potent immunomodulators and have powerful effects on asthma independent of their potential to act as antigens. Furthermore, our results provide a strong rationale for combination treatment strategies targeting IL-17A for this subgroup of fungus-exposed patients with difficult-to-treat asthma. To describe th

Phytophthora suppressor of RNA silencing 2 is a conserved RxLR effector that promotes infection in soybean and Arabidopsis thaliana.

PubMed

Xiong, Qin; Ye, Wenwu; Choi, Duseok; Wong, James; Qiao, Yongli; Tao, Kai; Wang, Yuanchao; Ma, Wenbo

2014-12-01

The genus Phytophthora consists of notorious and emerging pathogens of economically important crops. Each Phytophthora genome encodes several hundreds of cytoplasmic effectors, which are believed to manipulate plant immune response inside the host cells. However, the majority of Phytophthora effectors remain functionally uncharacterized. We recently discovered two effectors from the soybean stem and root rot pathogen Phytophthora sojae with the activity to suppress RNA silencing in plants. These effectors are designated Phytophthora suppressor of RNA silencing (PSRs). Here, we report that the P. sojae PSR2 (PsPSR2) belongs to a conserved and widespread effector family in Phytophthora. A PsPSR2-like effector produced by P. infestans (PiPSR2) can also suppress RNA silencing in plants and promote Phytophthora infection, suggesting that the PSR2 family effectors have conserved functions in plant hosts. Using Agrobacterium rhizogenes-mediated hairy roots induction, we demonstrated that the expression of PsPSR2 rendered hypersusceptibility of soybean to P. sojae. Enhanced susceptibility was also observed in PsPSR2-expressing Arabidopsis thaliana plants during Phytophthora but not bacterial infection. These experiments provide strong evidence that PSR2 is a conserved Phytophthora effector family that performs important virulence functions specifically during Phytophthora infection of various plant hosts.

A NEW SENSITIVE ASSAY FOR ANTIBODY AGAINST CELL SURFACE ANTIGENS BASED ON INHIBITION OF CELL-DEPENDENT ANTIBODY-MEDIATED CYTOTOXICITY

PubMed Central

Halloran, Phil; Schirrmacher, Volker; Festenstein, Hilliard

1974-01-01

Inhibition of cell-dependent antibody-mediated cytotoxicity has been investigated as a new assay for antibody against cell surface antigens. The cytotoxicity system consisted of effector cells (normal mouse spleen cells), target cells (61Cr-labeled chicken erythrocytes), and antitarget cell antibody. Addition of antibody against cell surface antigens in the effector cell population regularly inhibited the cytotoxicity measured in this system. This cytotoxicity inhibition assay (CIA) detected antibody with a variety of specificities: anti-H-2, anti-Thy 1.2, anti-immunoglobulin, and antimouse bone marrow-derived lymphocyte antigen. When the inhibition by anti-H-2 sera was analyzed using effector cells from congenic mice, the activity was found to be directed against specificities mapping in the H-2K, H-2D, and I regions of the H-2 complex, correlating well with the specificities characterized by complement-dependent assays. A comparison between the sensitivity of the CIA and complement-dependent lysis revealed that the CIA was 2–11 times more sensitive for anti-H-2 antisera and 20–780 times more sensitive for certain antisera against subpopulations of the spleen cells (i.e., T cells or B cells). The CIA proved to be precise, sensitive, and reliable. It may become a very useful antibody assay in various species including man. PMID:4547657

Activation‐Induced Killer Cell Immunoglobulin‐like Receptor 3DL2 Binding to HLA–B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis

PubMed Central

Ridley, Anna; Hatano, Hiroko; Wong‐Baeza, Isabel; Shaw, Jacqueline; Matthews, Katherine K.; Al‐Mossawi, Hussein; Ladell, Kristin; Price, David A.; Bowness, Paul

2016-01-01

Objective In the spondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin‐like receptor 3DL2 (KIR‐3DL2). The aim of this study was to determine the factors that induce KIR‐3DL2 expression, and to characterize the relationship between HLA–B27 and the phenotype and function of KIR‐3DL2–expressing CD4+ T cells in SpA. Methods In total, 34 B27+ patients with SpA, 28 age‐ and sex‐matched healthy controls (20 B27− and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template‐switch anchored reverse transcription–polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme‐linked immunosorbent assay. Results Cellular activation induced KIR‐3DL2 expression on both naive and effector CD4+ T cells. KIR‐3DL2 binding to B27+ cells promoted expression of KIR‐3DL2, the Th17‐specific transcription factor retinoic acid receptor–related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR‐3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen‐presenting cells, KIR‐3DL2+CD4+ T cells produced less interleukin‐2 (IL‐2) but more IL‐17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR‐3DL2 to B27 heavy chains. Conclusion KIR‐3DL2 binding to HLA–B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA–B27–KIR‐3DL2 interactions for the treatment of B27+ patients with SpA. PMID:26841353

Characterization of an immunomodulatory Der p 2-FIP-fve fusion protein produced in transformed rice suspension cell culture.

PubMed

Su, Chin-Fen; Kuo, I-Chun; Chen, Peng-Wen; Huang, Chiung-Hui; Seow, See Voon; Chua, Kaw Yan; Yu, Su-May

2012-02-01

Der p 2, a major allergen of Dermatophagoides pteronyssinus mites, is one of the most clinically relevant allergens to allergic patients worldwide. FIP-fve protein (Fve) from the golden needle mushroom (Flammulina velutipes) is an immunomodulatory protein with potential Th1-skewed adjuvant properties. Here, we produced and immunologically evaluated a Der p 2-Fve fusion protein as a potential immunotherapeutic for allergic diseases. Using an inducible expression system in cultured rice suspension cells, the recombinant Der p 2-Fve fusion protein (designated as OsDp2Fve) was expressed in rice cells under the control of an α-amylase gene (αAmy8) promoter and secreted under sucrose starvation. OsDp2Fve was partially purified from the cultured medium. The conformation of Der p 2 in OsDp2Fve remains intact as reflected by its unaltered allergenicity, as assessed by human IgE ELISA and histamine release assays, compared to non-fusion Der p 2 protein. Furthermore, the Fve protein expressed in OsDp2Fve retains its in vitro lymphoproliferative activity but loses its hemagglutination and lymphoagglutination effects compared to the native protein. Notably, in vivo evaluation showed that mice administered with OsDp2Fve possessed an enhanced production of Der p 2-specific IgG antibodies without potentiating the production of Der p 2-specific IgE and Th2 effector cytokines in comparison with mice co-administered with native Fve and Der p 2 proteins. These results suggest that the recombinant Der p 2-Fve fusion protein produced in rice suspension cell cultures has a great potential for allergy immunotherapy.

Integration of two RAB5 groups during endosomal transport in plants

PubMed Central

Ebine, Kazuo; Choi, Seung-won; Ichinose, Sakura; Uemura, Tomohiro; Nakano, Akihiko

2018-01-01

RAB5 is a key regulator of endosomal functions in eukaryotic cells. Plants possess two different RAB5 groups, canonical and plant-unique types, which act via unknown counteracting mechanisms. Here, we identified an effector molecule of the plant-unique RAB5 in Arabidopsis thaliana, ARA6, which we designated PLANT-UNIQUE RAB5 EFFECTOR 2 (PUF2). Preferential colocalization with canonical RAB5 on endosomes and genetic interaction analysis indicated that PUF2 coordinates vacuolar transport with canonical RAB5, although PUF2 was identified as an effector of ARA6. Competitive binding of PUF2 with GTP-bound ARA6 and GDP-bound canonical RAB5, together interacting with the shared activating factor VPS9a, showed that ARA6 negatively regulates canonical RAB5-mediated vacuolar transport by titrating PUF2 and VPS9a. These results suggest a unique and unprecedented function for a RAB effector involving the integration of two RAB groups to orchestrate endosomal trafficking in plant cells. PMID:29749929

Different features of Vδ2 T and NK cells in fatal and non-fatal human Ebola infections.

PubMed

Cimini, Eleonora; Viola, Domenico; Cabeza-Cabrerizo, Mar; Romanelli, Antonella; Tumino, Nicola; Sacchi, Alessandra; Bordoni, Veronica; Casetti, Rita; Turchi, Federica; Martini, Federico; Bore, Joseph A; Koundouno, Fara Raymond; Duraffour, Sophie; Michel, Janine; Holm, Tobias; Zekeng, Elsa Gayle; Cowley, Lauren; Garcia Dorival, Isabel; Doerrbecker, Juliane; Hetzelt, Nicole; Baum, Jonathan H J; Portmann, Jasmine; Wölfel, Roman; Gabriel, Martin; Miranda, Osvaldo; Díaz, Graciliano; Díaz, José E; Fleites, Yoel A; Piñeiro, Carlos A; Castro, Carlos M; Koivogui, Lamine; Magassouba, N'Faly; Diallo, Boubacar; Ruibal, Paula; Oestereich, Lisa; Wozniak, David M; Lüdtke, Anja; Becker-Ziaja, Beate; Capobianchi, Maria R; Ippolito, Giuseppe; Carroll, Miles W; Günther, Stephan; Di Caro, Antonino; Muñoz-Fontela, César; Agrati, Chiara

2017-05-01

Human Ebola infection is characterized by a paralysis of the immune system. A signature of αβ T cells in fatal Ebola infection has been recently proposed, while the involvement of innate immune cells in the protection/pathogenesis of Ebola infection is unknown. Aim of this study was to analyze γδ T and NK cells in patients from the Ebola outbreak of 2014-2015 occurred in West Africa, and to assess their association with the clinical outcome. Nineteen Ebola-infected patients were enrolled at the time of admission to the Ebola Treatment Centre in Guinea. Patients were divided in two groups on the basis of the clinical outcome. The analysis was performed by using multiparametric flow cytometry established by the European Mobile Laboratory in the field. A low frequency of Vδ2 T-cells was observed during Ebola infection, independently from the clinical outcome. Moreover, Vδ2 T-cells from Ebola patients massively expressed CD95 apoptotic marker, suggesting the involvement of apoptotic mechanisms in Vδ2 T-cell loss. Interestingly, Vδ2 T-cells from survivors expressed an effector phenotype and presented a lower expression of the CTLA-4 exhaustion marker than fatalities, suggesting a role of effector Vδ2 T-cells in the protection. Furthermore, patients with fatal Ebola infection were characterized by a lower NK cell frequency than patients with non fatal infection. In particular, both CD56bright and CD56dim NK frequency were very low both in fatal and non fatal infections, while a higher frequency of CD56neg NK cells was associated to non-fatal infections. Finally, NK activation and expression of NKp46 and CD158a were independent from clinical outcome. Altogether, the data suggest that both effector Vδ2 T-cells and NK cells may play a role in the complex network of protective response to EBOV infection. Further studies are required to characterize the protective effector functions of Vδ2 and NK cells.

Role of IL-1 Beta in the Development of Human TH17 Cells: Lesson from NLPR3 Mutated Patients

PubMed Central

Lasigliè, Denise; Traggiai, Elisabetta; Federici, Silvia; Alessio, Maria; Buoncompagni, Antonella; Accogli, Andrea; Chiesa, Sabrina; Penco, Federica; Martini, Alberto; Gattorno, Marco

2011-01-01

Background T helper 17 cells (TH-17) represent a lineage of effector T cells critical in host defence and autoimmunity. In both mouse and human IL-1β has been indicated as a key cytokine for the commitment to TH-17 cells. Cryopyrin-associated periodic syndromes (CAPS) are a group of inflammatory diseases associated with mutations of the NLRP3 gene encoding the inflammasome component cryopyrin. In this work we asked whether the deregulated secretion of IL-1β secondary to mutations characterizing these patients could affect the IL-23/IL-17 axis. Methodology/Principal Findings A total of 11 CAPS, 26 systemic onset juvenile idiopathic arthritis (SoJIA) patients and 20 healthy controls were analyzed. Serum levels of IL-17 and IL-6 serum were assessed by ELISA assay. Frequency of TH17 cells was quantified upon staphylococcus enterotoxin B (SEB) stimulation. Secretion of IL-1β, IL-23 and IL-6 by monocyte derived dendritic cells (MoDCs), were quantified by ELISA assay. A total of 8 CAPS and 11 SoJIA patients were also analysed before and after treatment with IL-1β blockade. Untreated CAPS patients showed significantly increased IL-17 serum levels as well as a higher frequency of TH17 compared to control subjects. On the contrary, SoJIA patients displayed a frequency of TH17 similar to normal donors, but were found to have significantly increased serum level of IL-6 when compared to CAPS patients or healthy donors. Remarkably, decreased IL-17 serum levels and TH17 frequency were observed in CAPS patients following in vivo IL-1β blockade. On the same line, MoDCs from CAPS patients exhibited enhanced secretion of IL-1β and IL-23 upon TLRs stimulation, with a reduction after anti-IL-1 treatment. Conclusion/Significance These findings further support the central role of IL-1β in the differentiation of TH17 in human inflammatory conditions. PMID:21637346

External lipid PI3P mediates entry of eukaryotic pathogen effectors into plant and animal host cells.

PubMed

Kale, Shiv D; Gu, Biao; Capelluto, Daniel G S; Dou, Daolong; Feldman, Emily; Rumore, Amanda; Arredondo, Felipe D; Hanlon, Regina; Fudal, Isabelle; Rouxel, Thierry; Lawrence, Christopher B; Shan, Weixing; Tyler, Brett M

2010-07-23

Pathogens of plants and animals produce effector proteins that are transferred into the cytoplasm of host cells to suppress host defenses. One type of plant pathogens, oomycetes, produces effector proteins with N-terminal RXLR and dEER motifs that enable entry into host cells. We show here that effectors of another pathogen type, fungi, contain functional variants of the RXLR motif, and that the oomycete and fungal RXLR motifs enable binding to the phospholipid, phosphatidylinositol-3-phosphate (PI3P). We find that PI3P is abundant on the outer surface of plant cell plasma membranes and, furthermore, on some animal cells. All effectors could also enter human cells, suggesting that PI3P-mediated effector entry may be very widespread in plant, animal and human pathogenesis. Entry into both plant and animal cells involves lipid raft-mediated endocytosis. Blocking PI3P binding inhibited effector entry, suggesting new therapeutic avenues. Copyright 2010 Elsevier Inc. All rights reserved.

Direct and Indirect Visualization of Bacterial Effector Delivery into Diverse Plant Cell Types during Infection[OPEN

PubMed Central

Henry, Elizabeth; Jauneau, Alain; Deslandes, Laurent

2017-01-01

To cause disease, diverse pathogens deliver effector proteins into host cells. Pathogen effectors can inhibit defense responses, alter host physiology, and represent important cellular probes to investigate plant biology. However, effector function and localization have primarily been investigated after overexpression in planta. Visualizing effector delivery during infection is challenging due to the plant cell wall, autofluorescence, and low effector abundance. Here, we used a GFP strand system to directly visualize bacterial effectors delivered into plant cells through the type III secretion system. GFP is a beta barrel that can be divided into 11 strands. We generated transgenic Arabidopsis thaliana plants expressing GFP1-10 (strands 1 to 10). Multiple bacterial effectors tagged with the complementary strand 11 epitope retained their biological function in Arabidopsis and tomato (Solanum lycopersicum). Infection of plants expressing GFP1-10 with bacteria delivering GFP11-tagged effectors enabled direct effector detection in planta. We investigated the temporal and spatial delivery of GFP11-tagged effectors during infection with the foliar pathogen Pseudomonas syringae and the vascular pathogen Ralstonia solanacearum. Thus, the GFP strand system can be broadly used to investigate effector biology in planta. PMID:28600390

Increased numbers of preexisting memory CD8 T cells and decreased T-bet expression can restrain terminal differentiation of secondary effector and memory CD8 T cells.

PubMed

Joshi, Nikhil S; Cui, Weiguo; Dominguez, Claudia X; Chen, Jonathan H; Hand, Timothy W; Kaech, Susan M

2011-10-15

Memory CD8 T cells acquire effector memory cell properties after reinfection and may reach terminally differentiated, senescent states ("Hayflick limit") after multiple infections. The signals controlling this process are not well understood, but we found that the degree of secondary effector and memory CD8 T cell differentiation was intimately linked to the amount of T-bet expressed upon reactivation and preexisting memory CD8 T cell number (i.e., primary memory CD8 T cell precursor frequency) present during secondary infection. Compared with naive cells, memory CD8 T cells were predisposed toward terminal effector (TE) cell differentiation because they could immediately respond to IL-12 and induce T-bet, even in the absence of Ag. TE cell formation after secondary (2°) or tertiary infections was dependent on increased T-bet expression because T-bet(+/-) cells were resistant to these phenotypic changes. Larger numbers of preexisting memory CD8 T cells limited the duration of 2° infection and the amount of IL-12 produced, and consequently, this reduced T-bet expression and the proportion of 2° TE CD8 T cells that formed. Together, these data show that over repeated infections, memory CD8 T cell quality and proliferative fitness is not strictly determined by the number of serial encounters with Ag or cell divisions, but is a function of the CD8 T cell differentiation state, which is genetically controlled in a T-bet-dependent manner. This differentiation state can be modulated by preexisting memory CD8 T cell number and the intensity of inflammation during reinfection. These results have important implications for vaccinations involving prime-boost strategies.

CCR4+T cell recruitment to the skin in mycosis fungoides: potential contributions by thymic stromal lymphopoietin and interleukin-16.

PubMed

Tuzova, Marina; Richmond, Jillian; Wolpowitz, Deon; Curiel-Lewandrowski, Clara; Chaney, Keri; Kupper, Thomas; Cruikshank, William

2015-02-01

Mycosis fungoides (MF) is characterized by skin accumulation of CCR4+CCR7- effector memory T cells; however the mechanism for their recruitment is not clearly identified. Thymic Stromal Lymphopoietin (TSLP) is a keratinocyte-derived cytokine that triggers Th2 immunity and is associated with T cell recruitment to the skin in atopic dermatitis. Interleukin-16 (IL-16) is a chemoattractant and growth factor for CD4+T cells. We hypothesized that TSLP and IL-16 could contribute to recruitment of malignant T cells in MF. We found elevated TSLP and IL-16 in very early stage patients' plasma and skin biopsies, prior to elevation in CCL22. Both TSLP and IL-16 induced migratory responses of CCR4+TSLPR+CD4+CCR7-CD31+cells, characteristic of malignant T cells in the skin. Co-stimulation also resulted in significant proliferative responses. We conclude that TSLP and IL-16, expressed at early stages of disease, function to recruit malignant T cells to the skin and contribute to their enhanced proliferation.

Human memory CD8 T cell effector potential is epigenetically preserved during in vivo homeostasis.

PubMed

Abdelsamed, Hossam A; Moustaki, Ardiana; Fan, Yiping; Dogra, Pranay; Ghoneim, Hazem E; Zebley, Caitlin C; Triplett, Brandon M; Sekaly, Rafick-Pierre; Youngblood, Ben

2017-06-05

Antigen-independent homeostasis of memory CD8 T cells is vital for sustaining long-lived T cell-mediated immunity. In this study, we report that maintenance of human memory CD8 T cell effector potential during in vitro and in vivo homeostatic proliferation is coupled to preservation of acquired DNA methylation programs. Whole-genome bisulfite sequencing of primary human naive, short-lived effector memory (T EM ), and longer-lived central memory (T CM ) and stem cell memory (T SCM ) CD8 T cells identified effector molecules with demethylated promoters and poised for expression. Effector-loci demethylation was heritably preserved during IL-7- and IL-15-mediated in vitro cell proliferation. Conversely, cytokine-driven proliferation of T CM and T SCM memory cells resulted in phenotypic conversion into T EM cells and was coupled to increased methylation of the CCR7 and Tcf7 loci. Furthermore, haploidentical donor memory CD8 T cells undergoing in vivo proliferation in lymphodepleted recipients also maintained their effector-associated demethylated status but acquired T EM -associated programs. These data demonstrate that effector-associated epigenetic programs are preserved during cytokine-driven subset interconversion of human memory CD8 T cells. © 2017 Abdelsamed et al.

Hierarchy Low CD4+/CD8+ T-Cell Counts and IFN-γ Responses in HIV-1+ Individuals Correlate with Active TB and/or M.tb Co-Infection.

PubMed

Shao, Lingyun; Zhang, Xinyun; Gao, Yan; Xu, Yunya; Zhang, Shu; Yu, Shenglei; Weng, Xinhua; Shen, Hongbo; Chen, Zheng W; Jiang, Weimin; Zhang, Wenhong

2016-01-01

Detailed studies of correlation between HIV-M.tb co-infection and hierarchy declines of CD8+/CD4+ T-cell counts and IFN-γ responses have not been done. We conducted case-control studies to address this issue. 164 HIV-1-infected individuals comprised of HIV-1+ATB, HIV-1+LTB and HIV-1+TB- groups were evaluated. Immune phenotyping and complete blood count (CBC) were employed to measure CD4+ and CD8+ T-cell counts; T.SPOT.TB and intracellular cytokine staining (ICS) were utilized to detect ESAT6, CFP10 or PPD-specific IFN-γ responses. There were significant differences in median CD4+ T-cell counts between HIV-1+ATB (164/μL), HIV-1+LTB (447/μL) and HIV-1+TB- (329/μL) groups. Hierarchy low CD4+ T-cell counts (<200/μL, 200-500/μL, >500/μL) were correlated significantly with active TB but not M.tb co-infection. Interestingly, hierarchy low CD8+ T-cell counts were not only associated significantly with active TB but also with M.tb co-infection (P<0.001). Immunologically, HIV-1+ATB group showed significantly lower numbers of ESAT-6-/CFP-10-specific IFN-γ+ T cells than HIV-1+LTB group. Consistently, PPD-specific IFN-γ+CD4+/CD8+ T effector cells in HIV-1+ATB group were significantly lower than those in HIV-1+LTB group (P<0.001). Hierarchy low CD8+ T-cell counts and effector function in HIV-1-infected individuals are correlated with both M.tb co-infection and active TB. Hierarchy low CD4+ T-cell counts and Th1 effector function in HIV-1+ individuals are associated with increased frequencies of active TB, but not M.tb co-infection.

Myeloid cell recruitment versus local proliferation differentiates susceptibility from resistance to filarial infection

PubMed Central

Campbell, Sharon M; Knipper, Johanna A; Ruckerl, Dominik; Finlay, Conor M; Logan, Nicola; Minutti, Carlos M; Mack, Matthias; Jenkins, Stephen J; Taylor, Matthew D

2018-01-01

Both TH2-dependent helminth killing and suppression of the TH2 effector response have been attributed to macrophages (MΦ) activated by IL-4 (M(IL-4)). To investigate how M(IL-4) contribute to diverse infection outcomes, the MΦ compartment of susceptible BALB/c mice and more resistant C57BL/6 mice was profiled during infection of the pleural cavity with the filarial nematode, Litomosoides sigmodontis. C57BL/6 mice exhibited a profoundly expanded resident MΦ (resMΦ) population, which was gradually replenished from the bone marrow in an age-dependent manner. Infection status did not alter the bone-marrow derived contribution to the resMΦ population, confirming local proliferation as the driver of resMΦ expansion. Significantly less resMΦ expansion was observed in the susceptible BALB/c strain, which instead exhibited an influx of monocytes that assumed an immunosuppressive PD-L2+ phenotype. Inhibition of monocyte recruitment enhanced nematode killing. Thus, the balance of monocytic vs. resident M(IL-4) numbers varies between inbred mouse strains and impacts infection outcome. PMID:29299998

Trichloroethylene-induced alterations in DNA methylation were enriched in polycomb protein binding sites in effector/memory CD4+ T cells

PubMed Central

Gilbert, Kathleen M.; Blossom, Sarah J.; Reisfeld, Brad; Erickson, Stephen W.; Vyas, Kanan; Maher, Mary; Broadfoot, Brannon; West, Kirk; Bai, Shasha; Cooney, Craig A.; Bhattacharyya, Sudeepa

2017-01-01

Abstract Exposure to industrial solvent and water pollutant trichloroethylene (TCE) can promote autoimmunity, and expand effector/memory (CD62L) CD4+ T cells. In order to better understand etiology reduced representation bisulfite sequencing was used to study how a 40-week exposure to TCE in drinking water altered methylation of ∼337 770 CpG sites across the entire genome of effector/memory CD4+ T cells from MRL+/+ mice. Regardless of TCE exposure, 62% of CpG sites in autosomal chromosomes were hypomethylated (0–15% methylation), and 25% were hypermethylated (85–100% methylation). In contrast, only 6% of the CpGs on the X chromosome were hypomethylated, and 51% had mid-range methylation levels. In terms of TCE impact, TCE altered (≥ 10%) the methylation of 233 CpG sites in effector/memory CD4+ T cells. Approximately 31.7% of these differentially methylated sites occurred in regions known to bind one or more Polycomb group (PcG) proteins, namely Ezh2, Suz12, Mtf2 or Jarid2. In comparison, only 23.3% of CpG sites not differentially methylated by TCE were found in PcG protein binding regions. Transcriptomics revealed that TCE altered the expression of ∼560 genes in the same effector/memory CD4+ T cells. At least 80% of the immune genes altered by TCE had binding sites for PcG proteins flanking their transcription start site, or were regulated by other transcription factors that were in turn ordered by PcG proteins at their own transcription start site. Thus, PcG proteins, and the differential methylation of their binding sites, may represent a new mechanism by which TCE could alter the function of effector/memory CD4+ T cells. PMID:29129997

Subcellular localization of the Hpa RxLR effector repertoire identifies a tonoplast-associated protein HaRxL17 that confers enhanced plant susceptibility.

PubMed

Caillaud, Marie-Cécile; Piquerez, Sophie J M; Fabro, Georgina; Steinbrenner, Jens; Ishaque, Naveed; Beynon, Jim; Jones, Jonathan D G

2012-01-01

Filamentous phytopathogens form sophisticated intracellular feeding structures called haustoria in plant cells. Pathogen effectors are likely to play a role in the establishment and maintenance of haustoria in addition to their better-characterized role in suppressing plant defence. However, the specific mechanisms by which these effectors promote virulence remain unclear. To address this question, we examined changes in subcellular architecture using live-cell imaging during the compatible interaction between the oomycete Hyaloperonospora arabidopsidis (Hpa) and its host Arabidopsis. We monitored host-cell restructuring of subcellular compartments within plant mesophyll cells during haustoria ontogenesis. Live-cell imaging highlighted rearrangements in plant cell membranes upon infection, in particular to the tonoplast, which was located close to the extra-haustorial membrane surrounding the haustorium. We also investigated the subcellular localization patterns of Hpa RxLR effector candidates (HaRxLs) in planta. We identified two major classes of HaRxL effector based on localization: nuclear-localized effectors and membrane-localized effectors. Further, we identified a single effector, HaRxL17, that associated with the tonoplast in uninfected cells and with membranes around haustoria, probably the extra-haustorial membrane, in infected cells. Functional analysis of selected effector candidates in planta revealed that HaRxL17 enhances plant susceptibility. The roles of subcellular changes and effector localization, with specific reference to the potential role of HaRxL17 in plant cell membrane trafficking, are discussed with respect to Hpa virulence. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Vitamin C treatment of mouse bone marrow-derived dendritic cells enhanced CD8(+) memory T cell production capacity of these cells in vivo.

PubMed

Jeong, Young-Joo; Kim, Jin-Hee; Hong, Jun-Man; Kang, Jae Seung; Kim, Hang-Rae; Lee, Wang Jae; Hwang, Young-il

2014-07-01

Vitamin C has been found to stimulate dendritic cells (DCs) to secrete more IL-12 and thereby drive naïve CD4(+) T cells to differentiate into Th1 cells. In the present study, we evaluated the effect of these vitamin C-treated DCs on CD8(+) T cell differentiation both in vitro and in vivo. Mouse bone marrow-derived DCs were prepared in the presence of GM-CSF and IL-15. With vitamin C treatment, these DCs, when LPS-stimulated, secreted more IL-12p70 and IL-15 than did untreated DCs. And when co-cultured with T cells, they yielded a higher frequency of IFN-γ(+) CD8(+) T cells. Moreover, we found that administering vitamin C-treated and tumor lysate-loaded DCs into mice yielded a higher frequency of CD44(high) CD62L(low) CD8(+) effector and effector memory T cells, which showed an increased ex vivo killing effect of the tumor cells. These DCs also elicited enhanced protective effects against inoculated tumor cells, most probably by way of the increased cytotoxic T cells, as was revealed by the decreased growth of the inoculated tumor cells in these mice. This ex vivo vitamin C treatment effect on DCs can be considered as a strategy for boosting DC vaccination potency against tumors. Copyright © 2014 Elsevier GmbH. All rights reserved.

KHYG-1 and NK-92 represent different subtypes of LFA-1-mediated NK cell adhesiveness.

PubMed

Suck, Garnet; Tan, Suet-Mien; Chu, Sixian; Niam, Madelaine; Vararattanavech, Ardcharaporn; Lim, Tsyr Jong; Koh, Mickey B C

2011-01-01

Novel cancer cellular therapy approaches involving long-term ex vivo IL-2 stimulated highly cytotoxic natural killer (NK) cells are emerging. However, adhesion properties of such NK cells are not very well understood. Herein, we describe the novel observation of permanently activated alphaLbeta2 integrin leukocyte function-associated antigen (LFA)-1 adhesion receptor in long-term IL-2 activated NK cells and the permanent NK cell lines KHYG-1 and NK-92. We show that such cytokine activated NK effectors constitutively adhered to the LFA-1-ligand ICAM-1, whereas binding to the lower affinity ligand ICAM-3 required additional exogenous activating conditions. The results demonstrate an extended conformation and an intermediate affinity state for the LFA-1 population expressed by the NK cells. Interestingly, adhesion to ICAM-1 or K562 induced pronounced cell spreading in KHYG-1, but not in NK-92, and partially in long-term IL-2 stimulated primary NK cells. It is conceivable that such differential adhesion characteristics may impact motility potential of such NK effectors with relevance to clinical tumor targeting. KHYG-1 could be a useful model in planning future targeted therapeutic approaches involving NK effectors with augmented functions.

Suppression of polymorphonuclear (PMN) and monocyte-mediated inhibition of Candida albicans growth by delta-9-tetrahydrocannabinol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Djeu, J.Y.; Parapanios, A.; Halkias, D.

This study was an in vitro attempt to identify the effector cells responsible for growth inhibition of the opportunistic fungus, candida albicans, and to determine if THC or another marijuana derivatives, 11-hydroxyTHC, would adversely affect their function. Using a 24h radiolabel assay, the authors found that growth inhibition of C. albicans was primarily mediated by PMN and monocytes that could be isolated normal human peripheral blood. Both effector cell types caused almost complete inhibition of Candida growth at effector/target ratio of 300/1 and inhibition was often still seen at 30/1-. Incubation of PMN, PBL, or monocytes for 1 hr atmore » 37C with THC or 11-hydroxyTHC caused a marked suppression of function in all 3 cell populations. Maximal suppression was obtained with 7.5-10..mu..g/ml of the drugs in medium containing 10% fetal bovine serum (FBS) or with 2-4..mu..g/ml in 1% FBS. These drug concentrations did not affect lymphoid cell viability or candida growth in the absence of lymphoid effector cells. Marijuana derivatives, therefore, are doubly dangerous in that opportunistic fungi such as C. albicans can grow in their presence while the effector cells that control fungal growth are readily inactivated.« less

Vitamin D Actions on CD4+ T Cells in Autoimmune Disease

PubMed Central

Hayes, Colleen Elizabeth; Hubler, Shane L.; Moore, Jerott R.; Barta, Lauren E.; Praska, Corinne E.; Nashold, Faye E.

2015-01-01

This review summarizes and integrates research on vitamin D and CD4+ T-lymphocyte biology to develop new mechanistic insights into the molecular etiology of autoimmune disease. A deep understanding of molecular mechanisms relevant to gene–environment interactions is needed to deliver etiology-based autoimmune disease prevention and treatment strategies. Evidence linking sunlight, vitamin D, and the risk of multiple sclerosis and type 1 diabetes is summarized to develop the thesis that vitamin D is the environmental factor that most strongly influences autoimmune disease development. Evidence for CD4+ T-cell involvement in autoimmune disease pathogenesis and for paracrine calcitriol signaling to CD4+ T lymphocytes is summarized to support the thesis that calcitriol is sunlight’s main protective signal transducer in autoimmune disease risk. Animal modeling and human mechanistic data are summarized to support the view that vitamin D probably influences thymic negative selection, effector Th1 and Th17 pathogenesis and responsiveness to extrinsic cell death signals, FoxP3+CD4+ T-regulatory cell and CD4+ T-regulatory cell type 1 (Tr1) cell functions, and a Th1–Tr1 switch. The proposed Th1–Tr1 switch appears to bridge two stable, self-reinforcing immune states, pro- and anti-inflammatory, each with a characteristic gene regulatory network. The bi-stable switch would enable T cells to integrate signals from pathogens, hormones, cell–cell interactions, and soluble mediators and respond in a biologically appropriate manner. Finally, unanswered questions and potentially informative future research directions are highlighted to speed delivery of etiology-based strategies to reduce autoimmune disease. PMID:25852682

Interleukin-17 receptor A maintains and protects the skin barrier to prevent allergic skin inflammation1

PubMed Central

Floudas, Achilleas; Saunders, Sean P.; Moran, Tara; Schwartz, Christian; Hams, Emily; Fitzgerald, Denise C.; Johnston, James A.; Ogg, Graham S.; McKenzie, Andrew N.; Walsh, Patrick T.; Fallon, Padraic G.

2017-01-01

Atopic dermatitis (AD) is a common inflammatory skin disease affecting up to 20% of children and 3% of adults worldwide and is associated with dysregulation of the skin barrier. While type 2 responses are implicated in AD, emerging evidence indicates potential role for the IL-17A signalling axis in AD pathogenesis. In this study we show that in the filaggrin mutant mouse model of spontaneous AD, IL-17RA deficiency (Il17ra-/-) resulted in severe exacerbation of skin inflammation. Interestingly, Il17ra-/- mice without the filaggrin mutation also developed spontaneous progressive skin inflammation with eosinophilia, increased levels of thymic stromal lymphopoietin (TSLP) and IL-5 in the skin. Il17ra-/- mice have a defective skin barrier with altered filaggrin expression. The barrier dysregulation and spontaneous skin inflammation in Il17ra-/- mice was dependent on TSLP, but not the other alarmins IL-25 and IL-33. The associated skin inflammation was mediated by IL-5 expressing pathogenic effector (pe) Th2 cells and was independent of TCRγδ T cells and IL-22. An absence of IL-17RA in non-hematopoietic cells, but not in the hematopoietic cells, was required for the development of spontaneous skin inflammation. Skin microbiome dysbiosis developed in the absence of IL-17RA, with antibiotic intervention resulting in significant amelioration of skin inflammation and reductions in skin infiltrating peTh2 cells and TSLP. This study describes a previously unappreciated protective role for IL-17RA signalling in regulation of the skin barrier and maintenance of skin immune homeostasis. PMID:28615416

Therapy-induced antitumor vaccination by targeting tumor necrosis factor alpha to tumor vessels in combination with melphalan.

PubMed

Mortara, Lorenzo; Balza, Enrica; Sassi, Francesca; Castellani, Patrizia; Carnemolla, Barbara; De Lerma Barbaro, Andrea; Fossati, Sara; Tosi, Giovanna; Accolla, Roberto S; Borsi, Laura

2007-12-01

Treatment of tumor-bearing mice with mouse (m)TNF-alpha, targeted to tumor vasculature by the anti-ED-B fibronectin domain antibody L19(scFv) and combined with melphalan, induces a therapeutic immune response. Upon treatment, a highly efficient priming of CD4+ T cells and consequent activation and maturation of CD8+ CTL effectors is generated, as demonstrated by in vivo depletion and adoptive cell transfer experiments. Immunohistochemical analysis of the tumor tissue demonstrated massive infiltration of CD4+ and CD8+ T cells 6 days after treatment and much earlier in the anamnestic response to tumor challenge in cured mice. In fact, the curative treatment with L19mTNF-alpha and melphalan resulted in long-lasting antitumor immune memory, accompanied by a mixed Th1/Th2-type response and significant in vitro tumor-specific cytolytic activity. Finally, the combined treatment reduced the percentage and absolute number of CD4+CD25+ regulatory T cells in the tumor-draining lymph nodes of mice responding to therapy, and this was associated with the establishment of protective immunity. These findings pave the way for alternative therapeutic strategies based on the targeted delivery of biological and pharmacological cytotoxic compounds that not only kill most of the tumor cells but, more importantly, trigger an effective and long-lasting antitumor adaptive immune response.

Comparative reactivity of human IgE to cynomolgus monkey and human effector cells and effects on IgE effector cell potency

PubMed Central

Saul, Louise; Saul, Louise; Josephs, Debra H; Josephs, Debra H; Cutler, Keith; Cutler, Keith; Bradwell, Andrew; Bradwell, Andrew; Karagiannis, Panagiotis; Karagiannis, Panagiotis; Selkirk, Chris; Selkirk, Chris; Gould, Hannah J; Gould, Hannah J; Jones, Paul; Jones, Paul; Spicer, James F; Spicer, James F; Karagiannis, Sophia N; Karagiannis, Sophia N

2014-01-01

Background: Due to genetic similarities with humans, primates of the macaque genus such as the cynomolgus monkey are often chosen as models for toxicology studies of antibody therapies. IgE therapeutics in development depend upon engagement with the FcεRI and FcεRII receptors on immune effector cells for their function. Only limited knowledge of the primate IgE immune system is available to inform the choice of models for mechanistic and safety evaluations.   Methods: The recognition of human IgE by peripheral blood lymphocytes from cynomolgus monkey and man was compared. We used effector cells from each species in ex vivo affinity, dose-response, antibody-receptor dissociation and potency assays. Results: We report cross-reactivity of human IgE Fc with cynomolgus monkey cells, and comparable binding kinetics to peripheral blood lymphocytes from both species. In competition and dissociation assays, however, human IgE dissociated faster from cynomolgus monkey compared with human effector cells. Differences in association and dissociation kinetics were reflected in effector cell potency assays of IgE-mediated target cell killing, with higher concentrations of human IgE needed to elicit effector response in the cynomolgus monkey system. Additionally, human IgE binding on immune effector cells yielded significantly different cytokine release profiles in each species. Conclusion: These data suggest that human IgE binds with different characteristics to human and cynomolgus monkey IgE effector cells. This is likely to affect the potency of IgE effector functions in these two species, and so has relevance for the selection of biologically-relevant model systems when designing pre-clinical toxicology and functional studies. PMID:24492303

Manipulation of intestinal epithelial cell function by the cell contact-dependent type III secretion systems of Vibrio parahaemolyticus

PubMed Central

O'Boyle, Nicky; Boyd, Aoife

2013-01-01

Vibrio parahaemolyticus elicits gastroenteritis by deploying Type III Secretion Systems (TTSS) to deliver effector proteins into epithelial cells of the human intestinal tract. The bacteria must adhere to the human cells to allow colonization and operation of the TTSS translocation apparatus bridging the bacterium and the host cell. This article first reviews recent advances in identifying the molecules responsible for intercellular adherence. V. parahaemolyticus possesses two TTSS, each of which delivers an exclusive set of effectors and mediates unique effects on the host cell. TTSS effectors primarily target and alter the activation status of host cell signaling proteins, thereby bringing about changes in the regulation of cellular behavior. TTSS1 is responsible for the cytotoxicity of V. parahaemolyticus, while TTSS2 is necessary for the enterotoxicity of the pathogen. Recent publications have elucidated the function of several TTSS effectors and their importance in the virulence of the bacterium. This review will explore the ability of the TTSS to manipulate activities of human intestinal cells and how this modification of cell function favors bacterial colonization and persistence of V. parahaemolyticus in the host. PMID:24455490

Protein Kinase LegK2 Is a Type IV Secretion System Effector Involved in Endoplasmic Reticulum Recruitment and Intracellular Replication of Legionella pneumophila ▿

PubMed Central

Hervet, Eva; Charpentier, Xavier; Vianney, Anne; Lazzaroni, Jean-Claude; Gilbert, Christophe; Atlan, Danièle; Doublet, Patricia

2011-01-01

Legionella pneumophila is the etiological agent of Legionnaires' disease. Crucial to the pathogenesis of this intracellular pathogen is its ability to subvert host cell defenses, permitting intracellular replication in specialized vacuoles within host cells. The Dot/Icm type IV secretion system (T4SS), which translocates a large number of bacterial effectors into host cell, is absolutely required for rerouting the Legionella phagosome. Many Legionella effectors display distinctive eukaryotic domains, among which are protein kinase domains. In silico analysis and in vitro phosphorylation assays identified five functional protein kinases, LegK1 to LegK5, encoded by the epidemic L. pneumophila Lens strain. Except for LegK5, the Legionella protein kinases are all T4SS effectors. LegK2 plays a key role in bacterial virulence, as demonstrated by gene inactivation. The legK2 mutant containing vacuoles displays less-efficient recruitment of endoplasmic reticulum markers, which results in delayed intracellular replication. Considering that a kinase-dead substitution mutant of legK2 exhibits the same virulence defects, we highlight here a new molecular mechanism, namely, protein phosphorylation, developed by L. pneumophila to establish a replicative niche and evade host cell defenses. PMID:21321072

At the Frontier; RXLR Effectors Crossing the Phytophthora-Host Interface.

PubMed

Bouwmeester, Klaas; Meijer, Harold J G; Govers, Francine

2011-01-01

Plants are constantly beset by pathogenic organisms. To successfully infect their hosts, plant pathogens secrete effector proteins, many of which are translocated to the inside of the host cell where they manipulate normal physiological processes and undermine host defense. The way by which effectors cross the frontier to reach the inside of the host cell varies among different classes of pathogens. For oomycete plant pathogens - like the potato late blight pathogen Phytophthora infestans - it has been shown that effector translocation to the host cell cytoplasm is dependent on conserved amino acid motifs that are present in the N-terminal part of effector proteins. One of these motifs, known as the RXLR motif, has a strong resemblance with a host translocation motif found in effectors secreted by Plasmodium species. These malaria parasites, that reside inside specialized vacuoles in red blood cells, make use of a specific protein translocation complex to export effectors from the vacuole into the red blood cell. Whether or not also oomycete RXLR effectors require a translocation complex to cross the frontier is still under investigation. For one P. infestans RXLR effector named IPI-O we have found a potential host target that could play a role in establishing the first contact between this effector and the host cell. This membrane spanning lectin receptor kinase, LecRK-I.9, interacts with IPI-O via the tripeptide RGD that overlaps with the RXLR motif. In animals, RGD is a well-known cell adhesion motif; it binds to integrins, which are membrane receptors that regulate many cellular processes and which can be hijacked by pathogens for either effector translocation or pathogen entry into host cells.

Isthmin 1 Is a Secreted Protein Expressed in Skin, Mucosal Tissues, and NK, NKT, and Th17 Cells

PubMed Central

Valle-Rios, Ricardo; Maravillas-Montero, José L.; Burkhardt, Amanda M.; Martinez, Cynthia; Buhren, Bettina Alexandra; Homey, Bernhard; Gerber, Peter Arne; Robinson, Octavio; Hevezi, Peter

2014-01-01

Using a comprehensive microarray database of human gene expression, we identified that in mammals, a secreted protein known as isthmin 1 (ISM1) is expressed in skin, mucosal tissues, and selected lymphocyte populations. ISM1 was originally identified in Xenopus brain during development, and it encodes a predicted ∼50-kDa protein containing a signal peptide, a thrombospondin domain, and an adhesion-associated domain. We confirmed the pattern of expression of ISM1 in both human and mouse tissues. ISM1 is expressed by DX5+ lung lymphocytes that include NK and NKT-like cells, and is also expressed by some CD4+ T cells upon activation but its expression increases significantly when CD4+ T cells were polarized to the Th17 lineage in vitro. The presence of IFN-γ during CD4+ T cell polarization inhibits ISM1 expression. Given that ISM1 has been reported to have anti-angiogenic properties, these observations suggest that ISM1 is a mediator of lymphocyte effector functions and may participate in both innate and acquired immune responses. PMID:24956034

Isthmin 1 is a secreted protein expressed in skin, mucosal tissues, and NK, NKT, and th17 cells.

PubMed

Valle-Rios, Ricardo; Maravillas-Montero, José L; Burkhardt, Amanda M; Martinez, Cynthia; Buhren, Bettina Alexandra; Homey, Bernhard; Gerber, Peter Arne; Robinson, Octavio; Hevezi, Peter; Zlotnik, Albert

2014-10-01

Using a comprehensive microarray database of human gene expression, we identified that in mammals, a secreted protein known as isthmin 1 (ISM1) is expressed in skin, mucosal tissues, and selected lymphocyte populations. ISM1 was originally identified in Xenopus brain during development, and it encodes a predicted ∼50-kDa protein containing a signal peptide, a thrombospondin domain, and an adhesion-associated domain. We confirmed the pattern of expression of ISM1 in both human and mouse tissues. ISM1 is expressed by DX5(+) lung lymphocytes that include NK and NKT-like cells, and is also expressed by some CD4(+) T cells upon activation but its expression increases significantly when CD4(+) T cells were polarized to the Th17 lineage in vitro. The presence of IFN-γ during CD4(+) T cell polarization inhibits ISM1 expression. Given that ISM1 has been reported to have anti-angiogenic properties, these observations suggest that ISM1 is a mediator of lymphocyte effector functions and may participate in both innate and acquired immune responses.

In vivo signaling through the neurokinin 1 receptor favors transgene expression by Langerhans cells and promotes the generation of Th1- and Tc1-biased immune responses.

PubMed

Mathers, Alicia R; Tckacheva, Olga A; Janelsins, Brian M; Shufesky, William J; Morelli, Adrian E; Larregina, Adriana T

2007-06-01

The proinflammatory capacities of the skin and the presence of high numbers of resident dendritic cells (DCs) constitute an ideal microenvironment for successful immunizations. Regardless of the ability of DCs to respond to local inflammatory signals in an immunostimulatory fashion, the immune functions of skin-resident DCs remain controversial, and epidermal Langerhans cells (LCs) have been referred to recently as anti-inflammatory/protolerogenic APCs. Substance P (SP), released by skin nerve fibers, is a potent proinflammatory neuropeptide that favors development of skin-associated cellular immunity. SP exerts its proinflammatory functions by binding with high affinity to the neurokinin 1 receptor (NK1R). In this study, we tested whether signaling skin cells via the NK1R promotes humoral and cellular immunity during skin genetic immunizations. We used the gene gun to deliver transgenic (tg) Ag to the skin of C57BL/6 mice and the selective NK1R agonist [Sar(9)Met (O(2)) (11)]-SP as a potential proinflammatory Th1-biasing adjuvant. Our strategy expressed tg Ag exclusively in the epidermis and induced a preferential migration of activated LCs to skin-draining lymph nodes. Local administration of the NK1R agonist during skin genetic immunizations increased significantly the expression of tg Ag by a mechanism involving the translocation of NF-kappaB into the nuclei of cutaneous DCs homing to skin-draining lymph nodes. Importantly, our immunization approach resulted in Th1 and T cytotoxic (CTL)-1 bias of effector T cells that supported cellular and Ab-mediated immune responses. We demonstrate that signaling skin cells via the NK1R provides the adjuvant effect which favors the immunostimulatory functions of LCs.

Diverse secreted effectors are required for Salmonella persistence in a mouse infection model.

PubMed

Kidwai, Afshan S; Mushamiri, Ivy; Niemann, George S; Brown, Roslyn N; Adkins, Joshua N; Heffron, Fred

2013-01-01

Salmonella enterica serovar Typhimurium causes typhoid-like disease in mice and is a model of typhoid fever in humans. One of the hallmarks of typhoid is persistence, the ability of the bacteria to survive in the host weeks after infection. Virulence factors called effectors facilitate this process by direct transfer to the cytoplasm of infected cells thereby subverting cellular processes. Secretion of effectors to the cell cytoplasm takes place through multiple routes, including two separate type III secretion (T3SS) apparati as well as outer membrane vesicles. The two T3SS are encoded on separate pathogenicity islands, SPI-1 and -2, with SPI-1 more strongly associated with the intestinal phase of infection, and SPI-2 with the systemic phase. Both T3SS are required for persistence, but the effectors required have not been systematically evaluated. In this study, mutations in 48 described effectors were tested for persistence. We replaced each effector with a specific DNA barcode sequence by allelic exchange and co-infected with a wild-type reference to calculate the ratio of wild-type parent to mutant at different times after infection. The competitive index (CI) was determined by quantitative PCR in which primers that correspond to the barcode were used for amplification. Mutations in all but seven effectors reduced persistence demonstrating that most effectors were required. One exception was CigR, a recently discovered effector that is widely conserved throughout enteric bacteria. Deletion of cigR increased lethality, suggesting that it may be an anti-virulence factor. The fact that almost all Salmonella effectors are required for persistence argues against redundant functions. This is different from effector repertoires in other intracellular pathogens such as Legionella.

Diverse Secreted Effectors Are Required for Salmonella Persistence in a Mouse Infection Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kidwai, Afshan S.; Mushamiri, Ivy T.; Niemann, George

Salmonella enterica serovar Typhimurium causes typhoid-like disease in mice and is a model of typhoid fever in humans. One of the hallmarks of typhoid is persistence, the ability of the bacteria to survive in the host weeks after infection. Virulence factors called effectors facilitate this process by direct transfer to the cytoplasm of infected cells thereby subverting cellular processes. Secretion of effectors to the cell cytoplasm takes place through multiple routes, including two separate type III secretion (T3SS) apparati as well as outer membrane vesicles. The two T3SS are encoded on separate pathogenicity islands, SPI-1 and -2, with SPI-1 moremore » strongly associated with the intestinal phase of infection, and SPI-2 with the systemic phase. Both T3SS are required for persistence, but the effectors required have not been systematically evaluated. In this study, mutations in 48 described effectors were tested for persistence. We replaced each effector with a specific DNA barcode sequence by allelic exchange and co-infected with a wild-type reference to calculate the ratio of wild-type parent to mutant at different times after infection. The competitive index (CI) was determined by quantitative PCR in which primers that correspond to the barcode were used for amplification. Mutations in all but seven effectors reduced persistence demonstrating that most effectors were required. One exception was CigR, a recently discovered effector that is widely conserved throughout enteric bacteria. Deletion of cigR increased lethality, suggesting that it may be an anti-virulence factor. The fact that almost all Salmonella effectors are required for persistence argues against redundant functions. This is different from effector repertoires in other intracellular pathogens such as Legionella.« less

Regulation of Effector Treg Cells in Murine Lupus.

PubMed

Chandrasekaran, Uma; Yi, Woelsung; Gupta, Sanjay; Weng, Chien-Huan; Giannopoulou, Eugenia; Chinenov, Yurii; Jessberger, Rolf; Weaver, Casey T; Bhagat, Govind; Pernis, Alessandra B

2016-06-01

Treg cells need to acquire an effector phenotype to function in settings of inflammation. Whether effector Treg cells can limit disease severity in lupus is unknown. Interferon regulatory factor 4 (IRF-4) is an essential controller of effector Treg cells and regulates their ability to express interleukin-10 (IL-10). In non-Treg cells, IRF-4 activity is modulated by interactions with DEF-6 and its homolog switch-associated protein 70 (SWAP-70). Although mice lacking both DEF-6 and SWAP-70 (double-knockout [DKO] mice) develop lupus, they display normal survival, suggesting that in DKO mice, Treg cells can moderate disease development. The purpose of this study was to investigate whether Treg cells from DKO mice have an increased capacity to become effector Treg cells due to the ability of DEF-6 and SWAP-70 to restrain IRF-4 activity. Treg cells were evaluated by fluorescence-activated cell sorting. The B lymphocyte-induced maturation protein 1 (BLIMP-1)/IL-10 axis was assessed by crossing DKO mice with BLIMP-1-YFP-10BiT dual-reporter mice. Deletion of IRF-4 in Treg cells from DKO mice was achieved by generating FoxP3(Cre) IRF-4(fl/fl) DKO mice. The concomitant absence of DEF-6 and SWAP-70 led to increased numbers of Treg cells, which acquired an effector phenotype in a cell-intrinsic manner. In addition, Treg cells from DKO mice exhibited enhanced expression of the BLIMP-1/IL-10 axis. Notably, DKO effector Treg cells survived and expanded as disease progressed. The accumulation of Treg cells from DKO mice was associated with the up-regulation of genes controlling autophagy. IRF-4 was required for the expansion and function of effector Treg cells from DKO mice. This study revealed the existence of mechanisms that, by acting on IRF-4, can fine-tune the function and survival of effector Treg cells in lupus. These findings suggest that the existence of a powerful effector Treg cell compartment that successfully survives in an unfavorable inflammatory environment could limit disease development. © 2016, American College of Rheumatology.

Stability improvement of a four cable-driven parallel manipulator using a center of mass balance system

NASA Astrophysics Data System (ADS)

Salafian, Iman; Stewart, Blake; Newman, Matthew; Zygielbaum, Arthur I.; Terry, Benjamin

2017-04-01

A four cable-driven parallel manipulator (CDPM), consisting of sophisticated spectrometers and imagers, is under development for use in acquiring phenotypic and environmental data over an acre-sized crop field. To obtain accurate and high quality data from the instruments, the end effector must be stable during sensing. One of the factors that reduces stability is the center of mass offset of the end effector, which can cause a pendulum effect or undesired tilt angle. The purpose of this work is to develop a system and method for balancing the center of mass of a 12th-scale CDPM to minimize vibration that can cause error in the acquired data. A simple method for balancing the end effector is needed to enable end users of the CDPM to arbitrarily add and remove sensors and imagers from the end effector as their experiments may require. A Center of Mass Balancing System (CMBS) is developed in this study which consists of an adjustable system of weights and a gimbal for tilt mitigation. An electronic circuit board including an orientation sensor, wireless data communication, and load cells was designed to validate the CMBS. To measure improvements gained by the CMBS, several static and dynamic experiments are carried out. In the experiments, the dynamic vibrations due to the translational motion and static orientation were measured with and without CMBS use. The results show that the CMBS system improves the stability of the end-effector by decreasing vibration and static tilt angle.

[Report on the 34th meeting of the German Clinical Immunology Workgroup, Frankfurt, 03.-04.11.2006].

PubMed

Aries, P M; Witte, T; Lamprecht, P

2007-02-01

The annual meeting of the Clinical Immunology Workgroup focused on autoimmune vasculitides. The role of innate immunity, T- and B-cells, and innovative therapies for autoimmune vasculitides was discussed. Further topics of the meeting were the role of endothelial microparticles, ghrelin and leptin, regulatory and effector-memory T-cells in ANCA-associated vasculitides, as well as the lethal midline granuloma, intracytoplasmic cytokine-profile in Behcet's disease, autoantibodies in rheumatoid arthritis, polyarteritis nodosa with cranial manifestation, ILT6 as genetic marker in multiple sclerosis and Sjögren's syndrome, alpha-fodrin autoantibodies in multiple sclerosis, interferon-g autoantibodies in a patient with atypical mycobacteriosis, and autoreactive T-cells in murine lupus.

IL-15 induces CD4 effector memory T cell production and tissue emigration in nonhuman primates.

PubMed

Picker, Louis J; Reed-Inderbitzin, Edward F; Hagen, Shoko I; Edgar, John B; Hansen, Scott G; Legasse, Alfred; Planer, Shannon; Piatak, Michael; Lifson, Jeffrey D; Maino, Vernon C; Axthelm, Michael K; Villinger, Francois

2006-06-01

HIV infection selectively targets CD4+ effector memory T (T EM) cells, resulting in dramatic depletion of CD4+ T cells in mucosal effector sites in early infection. Regeneration of the T EM cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4+ and CD8+ T EM cells with little effect on the naive or central memory T (T CM) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. T EM cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2'-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4+ T EM cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4 + T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets.

IL-15 induces CD4+ effector memory T cell production and tissue emigration in nonhuman primates

PubMed Central

Picker, Louis J.; Reed-Inderbitzin, Edward F.; Hagen, Shoko I.; Edgar, John B.; Hansen, Scott G.; Legasse, Alfred; Planer, Shannon; Piatak, Michael; Lifson, Jeffrey D.; Maino, Vernon C.; Axthelm, Michael K.; Villinger, Francois

2006-01-01

HIV infection selectively targets CD4+ effector memory T (TEM) cells, resulting in dramatic depletion of CD4+ T cells in mucosal effector sites in early infection. Regeneration of the TEM cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4+ and CD8+ TEM cells with little effect on the naive or central memory T (TCM) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. TEM cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2′-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4+ TEM cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4+ T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets. PMID:16691294

BID-F1 and BID-F2 Domains of Bartonella henselae Effector Protein BepF Trigger Together with BepC the Formation of Invasome Structures

PubMed Central

Truttmann, Matthias C.; Guye, Patrick; Dehio, Christoph

2011-01-01

The gram-negative, zoonotic pathogen Bartonella henselae (Bhe) translocates seven distinct Bartonella effector proteins (Beps) via the VirB/VirD4 type IV secretion system (T4SS) into human cells, thereby interfering with host cell signaling [1], [2]. In particular, the effector protein BepG alone or the combination of effector proteins BepC and BepF trigger massive F-actin rearrangements that lead to the establishment of invasome structures eventually resulting in the internalization of entire Bhe aggregates [2], [3]. In this report, we investigate the molecular function of the effector protein BepF in the eukaryotic host cell. We show that the N-terminal [E/T]PLYAT tyrosine phosphorylation motifs of BepF get phosphorylated upon translocation but do not contribute to invasome-mediated Bhe uptake. In contrast, we found that two of the three BID domains of BepF are capable to trigger invasome formation together with BepC, while a mutation of the WxxxE motif of the BID-F1 domain inhibited its ability to contribute to the formation of invasome structures. Next, we show that BepF function during invasome formation can be replaced by the over-expression of constitutive-active Rho GTPases Rac1 or Cdc42. Finally we demonstrate that BID-F1 and BID-F2 domains promote the formation of filopodia-like extensions in NIH 3T3 and HeLa cells as well as membrane protrusions in HeLa cells, suggesting a role for BepF in Rac1 and Cdc42 activation during the process of invasome formation. PMID:22043280

BID-F1 and BID-F2 domains of Bartonella henselae effector protein BepF trigger together with BepC the formation of invasome structures.

PubMed

Truttmann, Matthias C; Guye, Patrick; Dehio, Christoph

2011-01-01

The gram-negative, zoonotic pathogen Bartonella henselae (Bhe) translocates seven distinct Bartonella effector proteins (Beps) via the VirB/VirD4 type IV secretion system (T4SS) into human cells, thereby interfering with host cell signaling [1], [2]. In particular, the effector protein BepG alone or the combination of effector proteins BepC and BepF trigger massive F-actin rearrangements that lead to the establishment of invasome structures eventually resulting in the internalization of entire Bhe aggregates [2], [3]. In this report, we investigate the molecular function of the effector protein BepF in the eukaryotic host cell. We show that the N-terminal [E/T]PLYAT tyrosine phosphorylation motifs of BepF get phosphorylated upon translocation but do not contribute to invasome-mediated Bhe uptake. In contrast, we found that two of the three BID domains of BepF are capable to trigger invasome formation together with BepC, while a mutation of the WxxxE motif of the BID-F1 domain inhibited its ability to contribute to the formation of invasome structures. Next, we show that BepF function during invasome formation can be replaced by the over-expression of constitutive-active Rho GTPases Rac1 or Cdc42. Finally we demonstrate that BID-F1 and BID-F2 domains promote the formation of filopodia-like extensions in NIH 3T3 and HeLa cells as well as membrane protrusions in HeLa cells, suggesting a role for BepF in Rac1 and Cdc42 activation during the process of invasome formation.

Efficacy, safety and immunological actions of butanol-extracted FAHF-2 on peanut anaphylaxis

PubMed Central

Srivastava, Kamal; Yang, Nan; Chen, Yuming; Lopez-Exposito, Ivan; Song, Ying; Goldfarb, Joseph; Zhan, Jixun; Sampson, Hugh; Li, Xiu-Min

2010-01-01

Background Therapies for peanut allergy (PNA) are urgently needed. Food Allergy Herbal Formula -2 (FAHF-2) has profound therapeutic effects in a murine peanut allergy model and is safe for food allergic adults in clinical trials. However the large FAHF-2 pill-load is not conducive to clinical studies in children. Thus refining FAHF-2 to decrease pill-load is essential for the inclusion of children in clinical trials and to facilitate studying FAHF-2 as a clinically useful botanical drug. Objectives Testing long term efficacy and safety of a butanol-purified extract of FAHF-2 (B-FAHF-2) in a murine model of PNA, and to explore its immunological mechanisms of action. Methods FAHF-2 was purified by butanol extraction. C3H/HeJ mice with established PNA received the 1st course of B-FAHF-2 at 6 mg, twice daily for 7 weeks (PNA/B-FAHF-2) or water (PNA/Sham) and were then challenged immediately after completing the treatment and 6 more times every 1–2 months post treatment up to week 50. Mice then received a second course of B-FAHF-2 treatment at week 52 and were challenged at week 65. In vivo and in vitro immunological effects on T, B and mast cells were also determined. Results Butanol purification reduced the volume of the effective dose ~5 fold. All PNA/B-FAHF-2 mice were completely protected from peanut anaphylaxis until the 5th challenge after the 1st course of treatment, as compared to PNA/sham mice. Partial protection persisted up to 50 weeks. A 2nd treatment course restored complete protection. B-FAHF-2 significantly suppressed Th2 cytokine, IgE and histamine levels in vivo, and showed direct inhibition of Th2, IgE-producing B cells and mast cell activation in vitro. B-FAHF-2 had a high margin of safety. Conclusion and clinical relevance B-FAHF-2 produced long-lasting protection against PN anaphylaxis for approximately half of the murine lifespan without side effects. B-FAHF-2 exhibited direct effects on multiple food allergy effector cells. PMID:21121976

Bim controls IL-15 availability and limits engagement of multiple BH3-only proteins

PubMed Central

Kurtulus, S; Sholl, A; Toe, J; Tripathi, P; Raynor, J; Li, K-P; Pellegrini, M; Hildeman, D A

2015-01-01

During the effector CD8+ T-cell response, transcriptional differentiation programs are engaged that promote effector T cells with varying memory potential. Although these differentiation programs have been used to explain which cells die as effectors and which cells survive and become memory cells, it is unclear if the lack of cell death enhances memory. Here, we investigated effector CD8+ T-cell fate in mice whose death program has been largely disabled because of the loss of Bim. Interestingly, the absence of Bim resulted in a significant enhancement of effector CD8+ T cells with more memory potential. Bim-driven control of memory T-cell development required T-cell-specific, but not dendritic cell-specific, expression of Bim. Both total and T-cell-specific loss of Bim promoted skewing toward memory precursors, by enhancing the survival of memory precursors, and limiting the availability of IL-15. Decreased IL-15 availability in Bim-deficient mice facilitated the elimination of cells with less memory potential via the additional pro-apoptotic molecules Noxa and Puma. Combined, these data show that Bim controls memory development by limiting the survival of pre-memory effector cells. Further, by preventing the consumption of IL-15, Bim limits the role of Noxa and Puma in causing the death of effector cells with less memory potential. PMID:25124553

Bim controls IL-15 availability and limits engagement of multiple BH3-only proteins.

PubMed

Kurtulus, S; Sholl, A; Toe, J; Tripathi, P; Raynor, J; Li, K-P; Pellegrini, M; Hildeman, D A

2015-01-01

During the effector CD8+ T-cell response, transcriptional differentiation programs are engaged that promote effector T cells with varying memory potential. Although these differentiation programs have been used to explain which cells die as effectors and which cells survive and become memory cells, it is unclear if the lack of cell death enhances memory. Here, we investigated effector CD8+ T-cell fate in mice whose death program has been largely disabled because of the loss of Bim. Interestingly, the absence of Bim resulted in a significant enhancement of effector CD8+ T cells with more memory potential. Bim-driven control of memory T-cell development required T-cell-specific, but not dendritic cell-specific, expression of Bim. Both total and T-cell-specific loss of Bim promoted skewing toward memory precursors, by enhancing the survival of memory precursors, and limiting the availability of IL-15. Decreased IL-15 availability in Bim-deficient mice facilitated the elimination of cells with less memory potential via the additional pro-apoptotic molecules Noxa and Puma. Combined, these data show that Bim controls memory development by limiting the survival of pre-memory effector cells. Further, by preventing the consumption of IL-15, Bim limits the role of Noxa and Puma in causing the death of effector cells with less memory potential.

Leishmania Hijacks Myeloid Cells for Immune Escape

PubMed Central

Martínez-López, María; Soto, Manuel; Iborra, Salvador; Sancho, David

2018-01-01

Protozoan parasites of the Leishmania genus are the causative agents of leishmaniasis, a group of neglected tropical diseases whose clinical manifestations vary depending on the infectious Leishmania species but also on host factors. Recognition of the parasite by host myeloid immune cells is a key to trigger an effective Leishmania-specific immunity. However, the parasite is able to persist in host myeloid cells by evading, delaying and manipulating host immunity in order to escape host resistance and ensure its transmission. Neutrophils are first in infiltrating infection sites and could act either favoring or protecting against infection, depending on factors such as the genetic background of the host or the parasite species. Macrophages are the main host cells where the parasites grow and divide. However, macrophages are also the main effector population involved in parasite clearance. Parasite elimination by macrophages requires the priming and development of an effector Th1 adaptive immunity driven by specific subtypes of dendritic cells. Herein, we will provide a comprehensive outline of how myeloid cells regulate innate and adaptive immunity against Leishmania, and the mechanisms used by the parasites to promote their evasion and sabotage. Understanding the interactions between Leishmania and the host myeloid cells may lead to the development of new therapeutic approaches and improved vaccination to leishmaniases, an important worldwide health problem in which current therapeutic or preventive approaches are limited. PMID:29867798

Effector T-cells are expanded in systemic lupus erythematosus patients with high disease activity and damage indexes.

PubMed

Piantoni, S; Regola, F; Zanola, A; Andreoli, L; Dall'Ara, F; Tincani, A; Airo', P

2018-01-01

Background and objectives T-cell activation may be one of the pathogenic mechanisms of systemic lupus erythematosus (SLE). After repeated antigenic stimulation, T-cells undergo different modifications, leading to the differentiation into effector memory T-cells (CCR7-CD45RA-) and terminally differentiated effector memory (TDEM) T-cells (CCR7-CD45RA+). Similarly, down-modulation of CD28 may lead to the expansion of the CD28- T-cells, a subpopulation with peculiar effector activities. The aim of this study was the characterization of T-cell phenotype in a cohort of patients with SLE according to disease activity and damage index. Materials and methods Phenotypic analysis of peripheral blood T lymphocytes of 51 SLE patients and 21 healthy controls was done by flow-cytometry. SLE disease activity was evaluated by SLE Disease Activity Index-2000 (SLEDAI-2K) and damage by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology damage index (SDI). The variations between different groups were evaluated by Mann-Whitney test. Bonferroni correction was applied to adjust for multiple comparisons ( p adj ). Spearman rank test was used to evaluate the correlations between quantitative variables. Results CD4+ lymphopenia was found among SLE patients. Patients showed a trend for a higher percentage of TDEM among the CD4+ T-cell subpopulation in comparison with healthy controls ( p = .04). SLE patients were divided into two groups according to disease activity: patients with SLEDAI-2K ≥ 6 ( n = 13) had a higher percentage of circulating CD4+ T-cells with CD28- phenotype ( p adj  = .005) as well as those with an effector memory ( p adj  = .004) and TDEM ( p adj  = .002) phenotype and a trend of decrease of regulatory T-cells (TREGs) ( p = .02), in comparison with patients with low disease activity ( n = 38). Patients with damage (SDI ≥ 1) tended to show an expansion of TDEM among CD4+ T-cells as compared with patients with no damage ( p = .01). In SLE patients an inverse correlation was found between the percentages of TREGs and those of TDEM ( p < .01) or CD4 + CD28- ( p < .01) T-cells. Conclusions CD4+ T-cell subpopulations displaying phenotype characteristics of effector lymphocytes are proportionally expanded in patients with active SLE and a higher damage index. These findings may suggest a role of effector T-cells in the pathogenesis of the disease and in the mechanisms of damage in SLE.

FOXO1 opposition of CD8+ T cell effector programming confers early memory properties and phenotypic diversity.

PubMed

Delpoux, Arnaud; Lai, Chen-Yen; Hedrick, Stephen M; Doedens, Andrew L

2017-10-17

The factors and steps controlling postinfection CD8 + T cell terminal effector versus memory differentiation are incompletely understood. Whereas we found that naive TCF7 (alias "Tcf-1") expression is FOXO1 independent, early postinfection we report bimodal, FOXO1-dependent expression of the memory-essential transcription factor TCF7 in pathogen-specific CD8 + T cells. We determined the early postinfection TCF7 high population is marked by low TIM3 expression and bears memory signature hallmarks before the appearance of established memory precursor marker CD127 (IL-7R). These cells exhibit diminished TBET, GZMB, mTOR signaling, and cell cycle progression. Day 5 postinfection, TCF7 high cells express higher memory-associated BCL2 and EOMES, as well as increased accumulation potential and capacity to differentiate into memory phenotype cells. TCF7 retroviral transduction opposes GZMB expression and the formation of KLRG1 pos phenotype cells, demonstrating an active role for TCF7 in extinguishing the effector program and forestalling terminal differentiation. Past the peak of the cellular immune response, we report a gradient of FOXO1 and TCF7 expression, which functions to oppose TBET and orchestrate a continuum of effector-to-memory phenotypes.

Regulation of inflammatory chemokine receptors on blood T cells associated to the circulating versus liver chemokines in dengue fever.

PubMed

de-Oliveira-Pinto, Luzia Maria; Marinho, Cíntia Ferreira; Povoa, Tiago Fajardo; de Azeredo, Elzinandes Leal; de Souza, Luiza Assed; Barbosa, Luiza Damian Ribeiro; Motta-Castro, Ana Rita C; Alves, Ada M B; Ávila, Carlos André Lins; de Souza, Luiz José; da Cunha, Rivaldo Venâncio; Damasco, Paulo Vieira; Paes, Marciano Viana; Kubelka, Claire Fernandes

2012-01-01

Little is known about the role of chemokines/chemokines receptors on T cells in natural DENV infection. Patients from DENV-2 and -3- outbreaks were studied prospectively during the acute or convalescent phases. Expression of chemokine receptor and activation markers on lymphocyte subpopulations were determined by flow cytometry analysis, plasma chemokine ligands concentrations were measured by ELISA and quantification of CCL5/RANTES(+) cells in liver tissues from fatal dengue cases was performed by immunochemistry. In the acute DENV-infection, T-helper/T-cytotoxic type-1 cell (Th1/Tc1)-related CCR5 is significantly higher expressed on both CD4 and CD8 T cells. The Th1-related CXCR3 is up-regulated among CD4 T cells and Tc2-related CCR4 is up-regulated among CD8 T cells. In the convalescent phase, all chemokine receptor or chemokine ligand expression tends to reestablish control healthy levels. Increased CCL2/MCP-1 and CCL4/MIP-1β but decreased CCL5/RANTES levels were observed in DENV-patients during acute infection. Moreover, we showed an increased CD107a expression on CCR5 or CXCR3-expressing T cells and higher expression of CD29, CD44(HIGH) and CD127(LOW) markers on CCR4-expressing CD8 T cells in DENV-patients when compared to controls. Finally, liver from dengue fatal patients showed increased number of cells expressing CCL5/RANTES in three out of four cases compared to three death from a non-dengue patient. In conclusion, both Th1-related CCR5 and CXCR3 among CD4 T cells have a potential ability to exert cytotoxicity function. Moreover, Tc1-related CCR5 and Tc2-related CCR4 among CD8 T cells have a potential ability to exert effector function and migration based on cell markers evaluated. The CCR5 expression would be promoting an enhanced T cell recruitment into liver, a hypothesis that is corroborated by the CCL5/RANTES increase detected in hepatic tissue from dengue fatal cases. The balance between protective and pathogenic immune response mediated by chemokines during dengue fever will be discussed.

Regulation of Inflammatory Chemokine Receptors on Blood T Cells Associated to the Circulating Versus Liver Chemokines in Dengue Fever

PubMed Central

Povoa, Tiago Fajardo; de Azeredo, Elzinandes Leal; de Souza, Luiza Assed; Barbosa, Luiza Damian Ribeiro; Motta-Castro, Ana Rita C.; Alves, Ada M. B.; Ávila, Carlos André Lins; de Souza, Luiz José; da Cunha, Rivaldo Venâncio; Damasco, Paulo Vieira; Paes, Marciano Viana; Kubelka, Claire Fernandes

2012-01-01

Little is known about the role of chemokines/chemokines receptors on T cells in natural DENV infection. Patients from DENV-2 and -3- outbreaks were studied prospectively during the acute or convalescent phases. Expression of chemokine receptor and activation markers on lymphocyte subpopulations were determined by flow cytometry analysis, plasma chemokine ligands concentrations were measured by ELISA and quantification of CCL5/RANTES+ cells in liver tissues from fatal dengue cases was performed by immunochemistry. In the acute DENV-infection, T-helper/T-cytotoxic type-1 cell (Th1/Tc1)-related CCR5 is significantly higher expressed on both CD4 and CD8 T cells. The Th1-related CXCR3 is up-regulated among CD4 T cells and Tc2-related CCR4 is up-regulated among CD8 T cells. In the convalescent phase, all chemokine receptor or chemokine ligand expression tends to reestablish control healthy levels. Increased CCL2/MCP-1 and CCL4/MIP-1β but decreased CCL5/RANTES levels were observed in DENV-patients during acute infection. Moreover, we showed an increased CD107a expression on CCR5 or CXCR3-expressing T cells and higher expression of CD29, CD44HIGH and CD127LOW markers on CCR4-expressing CD8 T cells in DENV-patients when compared to controls. Finally, liver from dengue fatal patients showed increased number of cells expressing CCL5/RANTES in three out of four cases compared to three death from a non-dengue patient. In conclusion, both Th1-related CCR5 and CXCR3 among CD4 T cells have a potential ability to exert cytotoxicity function. Moreover, Tc1-related CCR5 and Tc2-related CCR4 among CD8 T cells have a potential ability to exert effector function and migration based on cell markers evaluated. The CCR5 expression would be promoting an enhanced T cell recruitment into liver, a hypothesis that is corroborated by the CCL5/RANTES increase detected in hepatic tissue from dengue fatal cases. The balance between protective and pathogenic immune response mediated by chemokines during dengue fever will be discussed. PMID:22815692

PD-1 inhibits antiviral immunity at the effector phase in the liver.

PubMed

Iwai, Yoshiko; Terawaki, Seigo; Ikegawa, Masaya; Okazaki, Taku; Honjo, Tasuku

2003-07-07

Unlike naive T cells, effector T cells can be activated by either T cell receptor signal or costimulatory signal alone and therefore the absence of costimulatory molecules on tissue cells cannot explain the tolerance mechanism at the effector phase. Here we report that PD-L1, the ligand for the immunoinhibitory receptor PD-1, was expressed on vascular endothelium in peripheral tissues. Liver nonparenchymal cells including sinusoidal endothelial cells and Kupffer cells constitutively expressed PD-L1 and inhibited proliferation and cell division of activated T cells expressing PD-1. The absence of PD-1 induced proliferation of effector T cells in the adenovirus-infected liver and resulted in rapid clearance of the virus. These results indicate that PD-1 plays an important role in T cell tolerance at the effector phase and the blockade of the PD-1 pathway can augment antiviral immunity.

Analysis of Putative Apoplastic Effectors from the Nematode, Globodera rostochiensis, and Identification of an Expansin-Like Protein That Can Induce and Suppress Host Defenses

PubMed Central

Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Côté, Olivier; Stare, Barbara Gerič; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

2015-01-01

The potato cyst nematode, Globodera rostochiensis, is an important pest of potato. Like other pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm, to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative G. rostochiensis putative apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Several CLAVATA3/ESR-like proteins induced developmental phenotypes, whereas predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. When directed to the apoplast with a signal peptide, two effectors, an ubiquitin extension protein (GrUBCEP12) and an expansin-like protein (GrEXPB2), suppressed defense responses including NB-LRR signaling induced in the cytoplasm. GrEXPB2 also elicited defense response in species- and sequence-specific manner. Our results are consistent with the scenario whereby potato cyst nematodes secrete effectors that modulate host cell fate and metabolism as well as modifying host cell walls. Furthermore, we show a novel role for an apoplastic expansin-like protein in suppressing intra-cellular defense responses. PMID:25606855

Analysis of putative apoplastic effectors from the nematode, Globodera rostochiensis, and identification of an expansin-like protein that can induce and suppress host defenses.

PubMed

Ali, Shawkat; Magne, Maxime; Chen, Shiyan; Côté, Olivier; Stare, Barbara Gerič; Obradovic, Natasa; Jamshaid, Lubna; Wang, Xiaohong; Bélair, Guy; Moffett, Peter

2015-01-01

The potato cyst nematode, Globodera rostochiensis, is an important pest of potato. Like other pathogens, plant parasitic nematodes are presumed to employ effector proteins, secreted into the apoplast as well as the host cytoplasm, to alter plant cellular functions and successfully infect their hosts. We have generated a library of ORFs encoding putative G. rostochiensis putative apoplastic effectors in vectors for expression in planta. These clones were assessed for morphological and developmental effects on plants as well as their ability to induce or suppress plant defenses. Several CLAVATA3/ESR-like proteins induced developmental phenotypes, whereas predicted cell wall-modifying proteins induced necrosis and chlorosis, consistent with roles in cell fate alteration and tissue invasion, respectively. When directed to the apoplast with a signal peptide, two effectors, an ubiquitin extension protein (GrUBCEP12) and an expansin-like protein (GrEXPB2), suppressed defense responses including NB-LRR signaling induced in the cytoplasm. GrEXPB2 also elicited defense response in species- and sequence-specific manner. Our results are consistent with the scenario whereby potato cyst nematodes secrete effectors that modulate host cell fate and metabolism as well as modifying host cell walls. Furthermore, we show a novel role for an apoplastic expansin-like protein in suppressing intra-cellular defense responses.

A Pseudomonas aeruginosa type VI secretion phospholipase D effector targets both prokaryotic and eukaryotic cells.

PubMed

Jiang, Feng; Waterfield, Nicholas R; Yang, Jian; Yang, Guowei; Jin, Qi

2014-05-14

Widely found in animal and plant-associated proteobacteria, type VI secretion systems (T6SSs) are potentially capable of facilitating diverse interactions with eukaryotes and/or other bacteria. Pseudomonas aeruginosa encodes three distinct T6SS haemolysin coregulated protein (Hcp) secretion islands (H1, H2, and H3-T6SS), each involved in different aspects of the bacterium's interaction with other organisms. Here we describe the characterization of a P. aeruginosa H3-T6SS-dependent phospholipase D effector, PldB, and its three tightly linked cognate immunity proteins. PldB targets the periplasm of prokaryotic cells and exerts an antibacterial activity. Surprisingly, PldB also facilitates intracellular invasion of host eukaryotic cells by activation of the PI3K/Akt pathway, revealing it to be a trans-kingdom effector. Our findings imply a potentially widespread T6SS-mediated mechanism, which deploys a single phospholipase effector to influence both prokaryotic cells and eukaryotic hosts. Copyright © 2014 Elsevier Inc. All rights reserved.

Altered Memory T-Cell Responses to Bacillus Calmette-Guerin and Tetanus Toxoid Vaccination and Altered Cytokine Responses to Polyclonal Stimulation in HIV-Exposed Uninfected Kenyan Infants.

PubMed

Garcia-Knight, Miguel A; Nduati, Eunice; Hassan, Amin S; Gambo, Faith; Odera, Dennis; Etyang, Timothy J; Hajj, Nassim J; Berkley, James Alexander; Urban, Britta C; Rowland-Jones, Sarah L

2015-01-01

Implementation of successful prevention of mother-to-child transmission of HIV strategies has resulted in an increased population of HIV-exposed uninfected (HEU) infants. HEU infants have higher rates of morbidity and mortality than HIV-unexposed (HU) infants. Numerous factors may contribute to poor health in HEU infants including immunological alterations. The present study assessed T-cell phenotype and function in HEU infants with a focus on memory Th1 responses to vaccination. We compared cross-sectionally selected parameters at 3 and 12 months of age in HIV-exposed (n = 42) and HU (n = 28) Kenyan infants. We measured ex vivo activated and bulk memory CD4 and CD8 T-cells and regulatory T-cells by flow cytometry. In addition, we measured the magnitude, quality and memory phenotype of antigen-specific T-cell responses to Bacillus Calmette-Guerin and Tetanus Toxoid vaccine antigens, and the magnitude and quality of the T cell response following polyclonal stimulation with staphylococcal enterotoxin B. Finally, the influence of maternal disease markers on the immunological parameters measured was assessed in HEU infants. Few perturbations were detected in ex vivo T-cell subsets, though amongst HEU infants maternal HIV viral load positively correlated with CD8 T cell immune activation at 12 months. Conversely, we observed age-dependent differences in the magnitude and polyfunctionality of IL-2 and TNF-α responses to vaccine antigens particularly in Th1 cells. These changes mirrored those seen following polyclonal stimulation, where at 3 months, cytokine responses were higher in HEU infants compared to HU infants, and at 12 months, HEU infant cytokine responses were consistently lower than those seen in HU infants. Finally, reduced effector memory Th1 responses to vaccine antigens were observed in HEU infants at 3 and 12 months and higher central memory Th1 responses to M. tuberculosis antigens were observed at 3 months only. Long-term monitoring of vaccine efficacy and T-cell immunity in this vulnerable population is warranted.

A phospholipase A1 antibacterial Type VI secretion effector interacts directly with the C-terminal domain of the VgrG spike protein for delivery.

PubMed

Flaugnatti, Nicolas; Le, Thi Thu Hang; Canaan, Stéphane; Aschtgen, Marie-Stéphanie; Nguyen, Van Son; Blangy, Stéphanie; Kellenberger, Christine; Roussel, Alain; Cambillau, Christian; Cascales, Eric; Journet, Laure

2016-03-01

The Type VI secretion system (T6SS) is a multiprotein machine that delivers protein effectors in both prokaryotic and eukaryotic cells, allowing interbacterial competition and virulence. The mechanism of action of the T6SS requires the contraction of a sheath-like structure that propels a needle towards target cells, allowing the delivery of protein effectors. Here, we provide evidence that the entero-aggregative Escherichia coli Sci-1 T6SS is required to eliminate competitor bacteria. We further identify Tle1, a toxin effector encoded by this cluster and showed that Tle1 possesses phospholipase A1 and A2 activities required for the interbacterial competition. Self-protection of the attacker cell is secured by an outer membrane lipoprotein, Tli1, which binds Tle1 in a 1:1 stoichiometric ratio with nanomolar affinity, and inhibits its phospholipase activity. Tle1 is delivered into the periplasm of the prey cells using the VgrG1 needle spike protein as carrier. Further analyses demonstrate that the C-terminal extension domain of VgrG1, including a transthyretin-like domain, is responsible for the interaction with Tle1 and its subsequent delivery into target cells. Based on these results, we propose an additional mechanism of transport of T6SS effectors in which cognate effectors are selected by specific motifs located at the C-terminus of VgrG proteins. © 2015 John Wiley & Sons Ltd.

Transition of late-stage effector T cells to CD27+ CD28+ tumor-reactive effector memory T cells in humans after adoptive cell transfer therapy

PubMed Central

Powell, Daniel J.; Dudley, Mark E.; Robbins, Paul F.; Rosenberg, Steven A.

2007-01-01

In humans, the pathways of memory T-cell differentiation remain poorly defined. Recently, adoptive cell transfer (ACT) of tumor-reactive T lymphocytes to metastatic melanoma patients after nonmyeloablative chemotherapy has resulted in persistence of functional, tumor-reactive lymphocytes, regression of disease, and induction of melanocyte-directed autoimmunity in some responding patients. In the current study, longitudinal phenotypic analysis was performed on melanoma antigen–specific CD8+ T cells during their transition from in vitro cultured effector cells to long-term persistent memory cells following ACT to 6 responding patients. Tumor-reactive T cells used for therapy were generally late-stage effector cells with a CD27Lo CD28Lo CD45RA− CD62 ligand− (CD62L−) CC chemokine receptor 7− (CCR7−) interleukin-7 receptor αLo (IL-7RαLo) phenotype. After transfer, rapid up-regulation and continued expression of IL-7Rα in vivo suggested an important role for IL-7R in immediate and long-term T-cell survival. Although the tumor antigen–specific T-cell population contracted between 1 and 4 weeks after transfer, stable numbers of CD27+ CD28+ tumor-reactive T cells were maintained, demonstrating their contribution to the development of long-term, melanoma-reactive memory CD8+ T cells in vivo. At 2 months after transfer, melanoma-reactive T cells persisted at high levels and displayed an effector memory phenotype, including a CD27+ CD28+ CD62L− CCR7− profile, which may explain in part their ability to mediate tumor destruction. PMID:15345595

Anti-GD2 mAb and Vorinostat synergize in the treatment of neuroblastoma

PubMed Central

Kroesen, Michiel; Büll, Christian; Gielen, Paul R.; Brok, Ingrid C.; Armandari, Inna; Wassink, Melissa; Looman, Maaike W. G.; Boon, Louis; den Brok, Martijn H.; Hoogerbrugge, Peter M.; Adema, Gosse J.

2016-01-01

ABSTRACT Neuroblastoma (NBL) is a childhood malignancy of the sympathetic nervous system. For high-risk NBL patients, the mortality rate is still over 50%, despite intensive multimodal treatment. Anti-GD2 monoclonal antibody (mAB) in combination with systemic cytokine immunotherapy has shown clinical efficacy in high-risk NBL patients. Targeted therapy using histone deacetylase inhibitors (HDACi) is currently being explored in cancer treatment and already shows promising results. Using our recently developed transplantable TH-MYCN NBL model, we here report that the HDAC inhibitor Vorinostat synergizes with anti-GD2 mAb therapy in reducing NBL tumor growth. Further mechanistic studies uncovered multiple mechanisms for the observed synergy, including Vorinostat-induced specific NBL cell death and upregulation of the tumor antigen GD2 on the cell surface of surviving NBL cells. Moreover, Vorinostat created a permissive tumor microenvironment (TME) for tumor-directed mAb therapy by increasing macrophage effector cells expressing high levels of Fc-receptors (FcR) and decreasing the number and function of myeloid-derived suppressor cells (MDSC). Collectively, these data imply further testing of other epigenetic modulators with immunotherapy and provide a strong basis for clinical testing of anti-GD2 plus Vorinostat combination therapy in NBL patients. PMID:27471639

Tolerogenic dendritic cells inhibit antiphospholipid syndrome derived effector/memory CD4⁺ T cell response to β2GPI.

PubMed

Torres-Aguilar, Honorio; Blank, Miri; Kivity, Shaye; Misgav, Mudi; Luboshitz, Jacob; Pierangeli, Silvia S; Shoenfeld, Yehuda

2012-01-01

The importance of β(2)-glycoprotein I (β(2)GPI)-specific CD4(+) T cells in the development of pathogenic processes in patients with antiphospholipid syndrome (APS) and APS mouse models is well established. Therefore, our objective is to manipulate the β2GPI specific CD4(+) T cells using tolerogenic dendritic cells (tDCs) to induce tolerance. We aim to evaluate the capability of tDCs to induce antigen-specific tolerance in effector/memory T cells from patients with APS and to elucidate the involved mechanism. DCs and tDCs were produced from patients with APS peripheral-blood-monocytes, using specific cytokines. β(2)GPI-specific tolerance induction was investigated by coculturing control DC (cDC) or tDC, β(2)GPI-loaded, with autologous effector/memory T cells, evaluating the proliferative response, phenotype, cytokines secretion, viability and regulatory T cells. Human monocyte-derived DCs treated with interleukin (IL)-10 and transforming growth factor β-1 (10/TGF-DC) induced β(2)GPI-specific-unresponsiveness in effector/memory CD4(+) T cells (46.5% ± 26.0 less proliferation) in 16 of 20 analysed patients with APS, without affecting the proliferative response to an unrelated candidin. In five analysed patients, 10/TGF-DC-stimulated T cells acquired an IL-2(low)interferon γ(low)IL-10(high) cytokine profile, with just a propensity to express higher numbers of Foxp3(+)CTLA-4(+) cells, but with an evident suppressive ability. In four of 10 analysed patients, 10/TGF-DC-stimulated T cell hyporesponsiveness could not be reverted and showed higher percentages of late apoptosis, p<0.02. The inherent tolerance induction resistance of activated T cells present during the development of autoimmune diseases has delayed the application of tDC as an alternative therapy. This study highlights the 10/TGF-DC feasibility to induce antigen-specific unresponsiveness in autoreactive T cells generated in patients with APS by inducing apoptosis or T cells with regulatory abilities.

Effector Regulatory T Cell Differentiation and Immune Homeostasis Depend on the Transcription Factor Myb.

PubMed

Dias, Sheila; D'Amico, Angela; Cretney, Erika; Liao, Yang; Tellier, Julie; Bruggeman, Christine; Almeida, Francisca F; Leahy, Jamie; Belz, Gabrielle T; Smyth, Gordon K; Shi, Wei; Nutt, Stephen L

2017-01-17

FoxP3-expressing regulatory T (Treg) cells are essential for maintaining immune homeostasis. Activated Treg cells undergo further differentiation into an effector state that highly expresses genes critical for Treg cell function, although how this process is coordinated on a transcriptional level is poorly understood. Here, we demonstrate that mice lacking the transcription factor Myb in Treg cells succumbed to a multi-organ inflammatory disease. Myb was specifically expressed in, and required for the differentiation of, thymus-derived effector Treg cells. The combination of transcriptome and genomic footprint analyses revealed that Myb directly regulated a large proportion of the gene expression specific to effector Treg cells, identifying Myb as a critical component of the gene regulatory network controlling effector Treg cell differentiation and function. Copyright © 2017 Elsevier Inc. All rights reserved.

Dimethyl fumarate modulation of immune and antioxidant responses: application to HIV therapy

PubMed Central

Gill, Alexander J.; Kolson, Dennis L.

2013-01-01

The persistence of chronic immune activation and oxidative stress in human immunodeficiency virus (HIV)-infected, antiretroviral drug-treated individuals are major obstacles to fully preventing HIV disease progression. The immune modulator and antioxidant dimethyl fumarate (DMF) is effective in treating immune-mediated diseases and it also has potential applications to limiting HIV disease progression. Among the relevant effects of DMF and its active metabolite monomethyl fumarate (MMF) are induction of a Th1 → Th2 lymphocyte shift, inhibition of pro-inflammatory cytokine signaling, inhibition of NF-κB nuclear translocation, inhibition of dendritic cell maturation, suppression of lymphocyte and endothelial cell adhesion molecule expression, and induction of the Nrf2-dependent antioxidant response element (ARE) and effector genes. Associated with these effects are reduced lymphocyte and monocyte infiltration into psoriatic skin lesions in humans and immune-mediated demyelinating brain lesions in rodents, which confirms potent systemic and central nervous system (CNS) effects. In addition, DMF and MMF limit HIV infection in macrophages in vitro, albeit by unknown mechanisms. Finally, DMF and MMF also suppress neurotoxin production from HIV-infected macrophages, which drives CNS neurodegeneration. Thus, DMF might protect against systemic and CNS complications in HIV infection through its effective suppression of immune activation, oxidative stress, HIV replication, and macrophage-associated neuronal injury. PMID:23971529

Long-distance endosome trafficking drives fungal effector production during plant infection

PubMed Central

Bielska, Ewa; Higuchi, Yujiro; Schuster, Martin; Steinberg, Natascha; Kilaru, Sreedhar; Talbot, Nicholas J.; Steinberg, Gero

2014-01-01

To cause plant disease, pathogenic fungi can secrete effector proteins into plant cells to suppress plant immunity and facilitate fungal infection. Most fungal pathogens infect plants using very long strand-like cells, called hyphae, that secrete effectors from their tips into host tissue. How fungi undergo long-distance cell signalling to regulate effector production during infection is not known. Here we show that long-distance retrograde motility of early endosomes (EEs) is necessary to trigger transcription of effector-encoding genes during plant infection by the pathogenic fungus Ustilago maydis. We demonstrate that motor-dependent retrograde EE motility is necessary for regulation of effector production and secretion during host cell invasion. We further show that retrograde signalling involves the mitogen-activated kinase Crk1 that travels on EEs and participates in control of effector production. Fungal pathogens therefore undergo long-range signalling to orchestrate host invasion. PMID:25283249

Long-distance endosome trafficking drives fungal effector production during plant infection.

PubMed

Bielska, Ewa; Higuchi, Yujiro; Schuster, Martin; Steinberg, Natascha; Kilaru, Sreedhar; Talbot, Nicholas J; Steinberg, Gero

2014-10-06

To cause plant disease, pathogenic fungi can secrete effector proteins into plant cells to suppress plant immunity and facilitate fungal infection. Most fungal pathogens infect plants using very long strand-like cells, called hyphae, that secrete effectors from their tips into host tissue. How fungi undergo long-distance cell signalling to regulate effector production during infection is not known. Here we show that long-distance retrograde motility of early endosomes (EEs) is necessary to trigger transcription of effector-encoding genes during plant infection by the pathogenic fungus Ustilago maydis. We demonstrate that motor-dependent retrograde EE motility is necessary for regulation of effector production and secretion during host cell invasion. We further show that retrograde signalling involves the mitogen-activated kinase Crk1 that travels on EEs and participates in control of effector production. Fungal pathogens therefore undergo long-range signalling to orchestrate host invasion.

Recombinant immunotoxins and retargeted killer cells: employing engineered antibody fragments for tumor-specific targeting of cytotoxic effectors.

PubMed

Wels, Winfried; Biburger, Markus; Müller, Tina; Dälken, Benjamin; Giesübel, Ulrike; Tonn, Torsten; Uherek, Christoph

2004-03-01

Over the past years, monoclonal antibodies have attracted enormous interest as targeted therapeutics, and a number of such reagents are in clinical use. However, responses could not be achieved in all patients with tumors expressing high levels of the respective target antigens, suggesting that other factors such as limited recruitment of endogenous immune effector mechanisms can also influence treatment outcome. This justifies the search for alternative, potentially more effective reagents. Antibody-toxins and cytolytic effector cells genetically modified to carry antibody-based receptors on the surface, represent such tailor-made targeting vehicles with the potential of improved tumor localization and enhanced efficacy. In this way, advances in recombinant antibody technology have made it possible to circumvent problems inherent in chemical coupling of antibodies and toxins, and have allowed construction via gene fusion of recombinant molecules which combine antibody-mediated recognition of tumor cells with specific delivery of potent protein toxins of bacterial or plant origin. Likewise, recombinant antibody fragments provide the basis for the construction of chimeric antigen receptors that, upon expression in cytotoxic T lymphocytes (CTLs) or natural killer (NK) cells, link antibody-mediated recognition of tumor antigens with these effector cells' potent cytolytic activities, thereby making them promising cellular therapeutics for adoptive cancer therapy. Here, general principles for the derivation of cytotoxic proteins and effector cells with antibody-dependent tumor specificity are summarized, and current strategies to employ these molecules and cells for directed cancer therapy are discussed, focusing mainly on the tumor-associated antigens epidermal growth factor receptor (EGFR) and the closely related ErbB2 (HER2) as targets.

Phytophthora parasitica Effector PpRxLR2 Suppresses Nicotiana benthamiana Immunity.

PubMed

Dalio, R J D; Maximo, H J; Oliveira, T S; Dias, R O; Breton, M C; Felizatti, H; Machado, M

2018-04-01

Phytophthora species secrete several classes of effector proteins during interaction with their hosts. These proteins can have multiple functions including modulation of host physiology and immunity. The RxLR effectors have the ability to enter plant cells using the plant machinery. Some of these effectors have been characterized as immunity suppressors; however, very little is known about their functions in the interaction between Phytophthora parasitica and its hosts. Using a bioinformatics pipeline, we have identified 172 candidate RxLR effectors (CREs) in the isolate IAC 01_95 of P. parasitica. Of these 172 CREs, 93 were found to be also present in eight other genomes of P. parasitica, isolated from different hosts and continents. After transcriptomics and gene expression analysis, we have found five CREs to be up-regulated in in-vitro and in-planta samples. Subsequently, we selected three CREs for functional characterization in the model plant Nicotiana benthamiana. We show that PpRxLR2 is able to completely suppress INF-1-induced cell death, whereas PpRxLR3 and PpRxLR5 moderately suppressed N. benthamiana immunity in a less-extensive manner. Moreover, we confirmed the effector-triggered susceptibility activity of these proteins after transient transformation and infection of N. benthamiana plants. All three CREs enhanced virulence of P. parasitica during the interaction with N. benthamiana. These effectors, in particular PpRxLR2, can be targeted for the development of biotechnology-based control strategies of P. parasitica diseases.

CD19+CD24hiCD38hiBregs involved in downregulate helper T cells and upregulate regulatory T cells in gastric cancer

PubMed Central

Wang, Weiwei; Yuan, Xiangliang; Chen, Hui; Xie, Guohua; Ma, Yanhui; Zheng, Yingxia; Zhou, Yunlan; Shen, Lisong

2015-01-01

Regulatory B cells (Bregs) play a critical role in inflammation and autoimmune disease. We characterized the role of Bregs in the progression of gastric cancer. We detected an increase in Bregs producing IL-10 both in peripheral blood mononuclear cells (PBMCs) and in gastric tumors. Multicolor flow cytometry analysis revealed that a subset of CD19+CD24hiCD38hi B cells produces IL-10. Functional studies indicated that increased Bregs do not inhibit the proliferation of CD3+T cells or CD4+ helper T cells (Th cells). However, Bregs do suppress the secretion of IFN-γ and TNF-α by CD4+Th cells. CD19+CD24hiCD38hiBregs were also found to correlate positively with CD4+FoxP3+ regulatory T cells (Tregs). Neutralization experiments showed that Bregs convert CD4+CD25− effector T cells to CD4+FoxP3+Tregs via TGF-β1. Collectively, these findings demonstrate that increased Bregs play a immunosuppressive role in gastric cancer by inhibiting T cells cytokines as well as conversion to Tregs. These results may provide new clues about the underlying mechanisms of immune escape in gastric cancer. PMID:26378021

In vivo modulation of thymus-derived lymphocytes with monoclonal antibodies in mice. III. Spontaneous and natural cytotoxic effector cells.

PubMed Central

Herbert, A G; Le Gros, G S; Bidawid, S; Watson, J D

1984-01-01

Cytotoxic effector cell populations in murine spleen can be characterized by the phenotype of the cytotoxic cells or the nature of target cells. Lytic events can be antigen-specific, MHC-restricted and clonal, or target cell-specific but apparently non-MHC-restricted. Two cytotoxic effectors of this latter category are spontaneous and natural killers. Normal spleen cells from (BALB/c X DBA/2J)F1 mice (CDF1) cultured without added antigen develop a population of Thy-1+ spontaneous cytotoxic lymphocytes (SCTL) that lyse the DBA/2J mastocytoma P815, as well as the BALB/c-derived plasmacytomas MOPC-11 and SP2/0. Cold target competition experiments reveal the BALB/c-derived plasmacytomas MOPC-11, SP2/0, J558 and the A strain-derived T cell lymphoma YAC-1, but not normal lymphoblasts, block the lysis of P815 target cells. Thus, while these tumour cells appear to express common antigens which are recognized by SCTL cells, plasmacytomas such as J558 are not susceptible to lysis by SCTL. The relationship of SCTL to natural killer (NK) cells was examined. In-vivo treatment of mice with monoclonal anti-Thy-1 antibody leads to a rapid loss of SCTL and precursors from the spleen, but there is a concomitant increase in NK cell activity. PMID:6607213

Role of mixed Th1 and Th2 serum cytokines on pathogenesis and prognosis of hantavirus pulmonary syndrome.

PubMed

Borges, Alessandra Abel; Campos, Gelse Mazzoni; Moreli, Marcos Lázaro; Moro Souza, Ricardo Luiz; Saggioro, Fabiano Pinto; Figueiredo, Glauciane Garcia; Livonesi, Márcia Cristina; Moraes Figueiredo, Luiz Tadeu

2008-01-01

The hantavirus pulmonary syndrome (HPS) is an emerging syndrome in the Americas. The disease results from intense immune activation and changes in vascular permeability. The aim of this study was to determine the profile of serum cytokines in HPS patients looking for correlation with the clinical parameters, severity and outcome of illness. Studying 21 HPS patients, we found that IL-6 may have an important role in the pathogenesis of HPS, being associated with fatal outcome. Our results also support a mixed Th1/Th2 immune response during the course of HPS and that the magnitude of Th1 response effector cytokines is correlated to HPS severity. The decreased levels of TGF-beta observed in HPS patients suggest that immunoregulatory activity could be damaged in these patients.

Sympathetic neural signaling via the β2-adrenergic receptor suppresses T-cell receptor-mediated human and mouse CD8(+) T-cell effector function.

PubMed

Estrada, Leonardo D; Ağaç, Didem; Farrar, J David

2016-08-01

Postganglionic sympathetic neurons innervate secondary lymphoid organs and secrete norepinephrine (NE) as the primary neurotransmitter. NE binds and signals through five distinct members of the adrenergic receptor family. In this study, we show elevated expression of the β2-adrenergic receptor (ADRB2) on primary human CD8(+) effector memory T cells. Treatment of both human and murine CD8(+) T cells with NE decreased IFN-γ and TNF-α secretion and suppressed their cytolytic capacity in response to T-cell receptor (TCR) activation. The effects of NE were specifically reversed by β2-specific antagonists. Adrb2(-/-) CD8(+) T cells were completely resistant to the effects of NE. Further, the ADRB2-specific pharmacological ligand, albuterol, significantly suppressed effector functions in both human and mouse CD8(+) T cells. While both TCR activation and stimulation with IL-12 + IL-18 were able to induce inflammatory cytokine secretion, NE failed to suppress IFN-γ secretion in response to IL-12 + IL18. Finally, the long-acting ADRB2-specific agonist, salmeterol, markedly reduced the cytokine secretion capacity of CD8(+) T cells in response to infection with vesicular stomatitis virus. This study reveals a novel intrinsic role for ADRB2 signaling in CD8(+) T-cell function and underscores the novel role this pathway plays in adaptive T-cell responses to infection. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of protective immunity to Salmonella, a mucosal pathogen with a systemic agenda

PubMed Central

Griffin, Amanda J.; McSorley, Stephen J.

2014-01-01

Salmonella infections can cause a range of intestinal and systemic disease in human and animal hosts. While some Salmonella serovars initiate a localized intestinal inflammatory response, others use the intestine as a portal of entry to initiate a systemic infection. Considerable progress has been made in understanding bacterial invasion and dissemination strategies and the nature of the Salmonella-specific immune response to oral infection. Innate and adaptive immunity are rapidly initiated after oral infection but these effector responses can also be hindered by bacterial evasion strategies. Furthermore, although Salmonella resides within intramacrophage phagosomes, recent studies highlight a surprising collaboration of CD4 Th1, Th17, and B cell responses in mediating resistance to Salmonella infection. PMID:21307847

Parallel Aspects of the Microenvironment in Cancer and Autoimmune Disease

PubMed Central

Rahat, Michal A.

2016-01-01

Cancer and autoimmune diseases are fundamentally different pathological conditions. In cancer, the immune response is suppressed and unable to eradicate the transformed self-cells, while in autoimmune diseases it is hyperactivated against a self-antigen, leading to tissue injury. Yet, mechanistically, similarities in the triggering of the immune responses can be observed. In this review, we highlight some parallel aspects of the microenvironment in cancer and autoimmune diseases, especially hypoxia, and the role of macrophages, neutrophils, and their interaction. Macrophages, owing to their plastic mode of activation, can generate a pro- or antitumoral microenvironment. Similarly, in autoimmune diseases, macrophages tip the Th1/Th2 balance via various effector cytokines. The contribution of neutrophils, an additional plastic innate immune cell population, to the microenvironment and disease progression is recently gaining more prominence in both cancer and autoimmune diseases, as they can secrete cytokines, chemokines, and reactive oxygen species (ROS), as well as acquire an enhanced ability to produce neutrophil extracellular traps (NETs) that are now considered important initiators of autoimmune diseases. Understanding the contribution of macrophages and neutrophils to the cancerous or autoimmune microenvironment, as well as the role their interaction and cooperation play, may help identify new targets and improve therapeutic strategies. PMID:26997761

US_EVA_48_Part_2-of-5

NASA Image and Video Library

2018-02-20

Outside the International Space Station, Expedition 54 Flight Engineers Mark Vande Hei of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) conducted a spacewalk to move a Latching End Effector, or hand, for the Canadarm2 robotic arm into the Quest airlock that was removed during another excursion last October and to move a degraded end effector replaced during a Jan. 23 spacewalk onto a payload attachment device on the station’s Mobile Base System railcar. The spacewalk was the 208th in station history for assembly, maintenance and upgrades, the fourth in Vande Hei’s career and the first for Kanai, who became only the fourth Japanese astronaut to walk in space.

Xanthomonas euvesicatoria type III effector XopQ interacts with tomato and pepper 14-3-3 isoforms to suppress effector-triggered immunity.

PubMed

Teper, Doron; Salomon, Dor; Sunitha, Sukumaran; Kim, Jung-Gun; Mudgett, Mary Beth; Sessa, Guido

2014-01-01

Effector-triggered immunity (ETI) to host-adapted pathogens is associated with rapid cell death at the infection site. The plant-pathogenic bacterium Xanthomonas euvesicatoria (Xcv) interferes with plant cellular processes by injecting effector proteins into host cells through the type III secretion system. Here, we show that the Xcv effector XopQ suppresses cell death induced by components of the ETI-associated MAP kinase cascade MAPKKKα MEK2/SIPK and by several R/avr gene pairs. Inactivation of xopQ by insertional mutagenesis revealed that this effector inhibits ETI-associated cell death induced by avirulent Xcv in resistant pepper (Capsicum annuum), and enhances bacterial growth in resistant pepper and tomato (Solanum lycopersicum). Using protein-protein interaction studies in yeast (Saccharomyces cerevisiae) and in planta, we identified the tomato 14-3-3 isoform SlTFT4 and homologs from other plant species as XopQ interactors. A mutation in the putative 14-3-3 binding site of XopQ impaired interaction of the effector with CaTFT4 in yeast and its virulence function in planta. Consistent with a role in ETI, TFT4 mRNA abundance increased during the incompatible interaction of tomato and pepper with Xcv. Silencing of NbTFT4 in Nicotiana benthamiana significantly reduced cell death induced by MAPKKKα. In addition, silencing of CaTFT4 in pepper delayed the appearance of ETI-associated cell death and enhanced growth of virulent and avirulent Xcv, demonstrating the requirement of TFT4 for plant immunity to Xcv. Our results suggest that the XopQ virulence function is to suppress ETI and immunity-associated cell death by interacting with TFT4, which is an important component of ETI and a bona fide target of XopQ. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Different features of Vδ2 T and NK cells in fatal and non-fatal human Ebola infections

PubMed Central

Cimini, Eleonora; Viola, Domenico; Cabeza-Cabrerizo, Mar; Romanelli, Antonella; Tumino, Nicola; Sacchi, Alessandra; Bordoni, Veronica; Casetti, Rita; Turchi, Federica; Martini, Federico; Bore, Joseph A.; Koundouno, Fara Raymond; Duraffour, Sophie; Michel, Janine; Holm, Tobias; Zekeng, Elsa Gayle; Cowley, Lauren; Garcia Dorival, Isabel; Doerrbecker, Juliane; Hetzelt, Nicole; Baum, Jonathan H. J.; Portmann, Jasmine; Wölfel, Roman; Gabriel, Martin; Miranda, Osvaldo; Díaz, Graciliano; Díaz, José E.; Fleites, Yoel A.; Piñeiro, Carlos A.; Castro, Carlos M.; Koivogui, Lamine; Magassouba, N’Faly; Diallo, Boubacar; Ruibal, Paula; Oestereich, Lisa; Wozniak, David M.; Lüdtke, Anja; Becker-Ziaja, Beate; Capobianchi, Maria R.; Ippolito, Giuseppe; Carroll, Miles W.; Günther, Stephan; Di Caro, Antonino; Muñoz-Fontela, César

2017-01-01

Background Human Ebola infection is characterized by a paralysis of the immune system. A signature of αβ T cells in fatal Ebola infection has been recently proposed, while the involvement of innate immune cells in the protection/pathogenesis of Ebola infection is unknown. Aim of this study was to analyze γδ T and NK cells in patients from the Ebola outbreak of 2014–2015 occurred in West Africa, and to assess their association with the clinical outcome. Methodology/Principal findings Nineteen Ebola-infected patients were enrolled at the time of admission to the Ebola Treatment Centre in Guinea. Patients were divided in two groups on the basis of the clinical outcome. The analysis was performed by using multiparametric flow cytometry established by the European Mobile Laboratory in the field. A low frequency of Vδ2 T-cells was observed during Ebola infection, independently from the clinical outcome. Moreover, Vδ2 T-cells from Ebola patients massively expressed CD95 apoptotic marker, suggesting the involvement of apoptotic mechanisms in Vδ2 T-cell loss. Interestingly, Vδ2 T-cells from survivors expressed an effector phenotype and presented a lower expression of the CTLA-4 exhaustion marker than fatalities, suggesting a role of effector Vδ2 T-cells in the protection. Furthermore, patients with fatal Ebola infection were characterized by a lower NK cell frequency than patients with non fatal infection. In particular, both CD56bright and CD56dim NK frequency were very low both in fatal and non fatal infections, while a higher frequency of CD56neg NK cells was associated to non-fatal infections. Finally, NK activation and expression of NKp46 and CD158a were independent from clinical outcome. Conclusions/Significances Altogether, the data suggest that both effector Vδ2 T-cells and NK cells may play a role in the complex network of protective response to EBOV infection. Further studies are required to characterize the protective effector functions of Vδ2 and NK cells. PMID:28558022

High immunosuppressive burden in advanced hepatocellular carcinoma patients: Can effector functions be restored?

PubMed

Lugade, Amit A; Kalathil, Suresh; Miller, Austin; Iyer, Renuka; Thanavala, Yasmin

2013-07-01

The accumulation of immunosuppressive cells and exhausted effector T cells highlight an important immune dysfunction in advanced stage hepatocellular carcinoma (HCC) patients. These cells significantly hamper the efficacy immunotherapies and facilitate HCC progression. We have recently demonstrated that the multipronged depletion of immunosuppressive cells potentially restores effector T-cell function in HCC.

Potential Function of Granulysin, Other Related Effector Molecules and Lymphocyte Subsets in Patients with TB and HIV/TB Coinfection

PubMed Central

Pitabut, Nada; Sakurada, Shinsaku; Tanaka, Takahiro; Ridruechai, Chutharut; Tanuma, Junko; Aoki, Takahiro; Kantipong, Pacharee; Piyaworawong, Surachai; Kobayashi, Nobuyuki; Dhepakson, Panadda; Yanai, Hideki; Yamada, Norio; Oka, Shinichi; Okada, Masaji; Khusmith, Srisin; Keicho, Naoto

2013-01-01

Background: Host effector mechanism against Mycobacterium tuberculosis (Mtb) infection is dependent on innate immune response by macrophages and neutrophils and the alterations in balanced adaptive immunity. Coordinated release of cytolytic effector molecules from NK cells and effector T cells and the subsequent granule-associated killing of infected cells have been documented; however, their role in clinical tuberculosis (TB) is still controversy. Objective: To investigate whether circulating granulysin and other effector molecules are associated with the number of NK cells, iNKT cells, Vγ9+Vδ2+ T cells, CD4+ T cells and CD8+ T cells, and such association influences the clinical outcome of the disease in patients with pulmonary TB and HIV/TB coinfection. Methods: Circulating granulysin, perforin, granzyme-B and IFN-γ levels were determined by ELISA. The isoforms of granulysin were analyzed by Western blot analysis. The effector cells were analyzed by flow cytometry. Results: Circulating granulysin and perforin levels in TB patients were lower than healthy controls, whereas the granulysin levels in HIV/TB coinfection were much higher than in any other groups, TB and HIV with or without receiving HAART, which corresponded to the number of CD8+ T cells which kept high, but not with NK cells and other possible cellular sources of granulysin. In addition, the 17kDa, 15kDa and 9kDa isoforms of granulysin were recognized in plasma of HIV/TB coinfection. Increased granulysin and decreased IFN-γ levels in HIV/TB coinfection and TB after completion of anti-TB therapy were observed. Conclusion: The results suggested that the alteration of circulating granulysin has potential function in host immune response against TB and HIV/TB coinfection. This is the first demonstration so far of granulysin in HIV/TB coinfection. PMID:23801887

Differential requirements for activation and growth of unprimed cytotoxic and helper T lymphocytes.

PubMed

Gullberg, M; Pobor, G; Bandeira, A; Larsson, E L; Coutinho, A

1983-09-01

The requirements for activation and growth of T lymphocytes capable of mediating either cytolytic activity or help to B lymphocytes were studied in unprimed splenic T cell populations. The selectivity of expression of Lyt-2 antigens, the reactivity to soluble concanavalin A (Con A), to partially purified interleukin 2 (IL 2, T cell growth factor[s]) and to lectin-pulsed macrophages (M phi) were used in this analysis. Lectin-dependent cytotoxicity assays and a novel method that allows for the detection of all effector helper cells, regardless of their clonal specificities, were used for the functional identification of the responding T cells. The results show a marked contrast between cytolytic and helper T cells in their growth and activation requirements. Thus, while Lyt-2+ cytotoxic T lymphocyte precursors grow exponentially in IL 2 after a short pulse with soluble Con A in the absence of accessory cells, Lyt-2- helper cell precursors completely fail to proliferate under the same conditions and require the continuous presence of lectin-pulsed M phi for significant growth. Furthermore, addition of IL 2 to M phi-stimulated cultures of Lyt-2- cells has no effect. T cells which produce IL 2 have the same growth characteristics as helper cells. In both cases, effector helper functions could be expanded more than 10-fold on a per cell basis by a 5-day-culture period under those growth supporting conditions. The development of effector helper functions, however, was strongly inhibited by the presence of Lyt-2+ T cells.

Structural and biochemical characterization of SrcA, a multi-cargo type III secretion chaperone in Salmonella required for pathogenic association with a host.

PubMed

Cooper, Colin A; Zhang, Kun; Andres, Sara N; Fang, Yuan; Kaniuk, Natalia A; Hannemann, Mandy; Brumell, John H; Foster, Leonard J; Junop, Murray S; Coombes, Brian K

2010-02-05

Many Gram-negative bacteria colonize and exploit host niches using a protein apparatus called a type III secretion system (T3SS) that translocates bacterial effector proteins into host cells where their functions are essential for pathogenesis. A suite of T3SS-associated chaperone proteins bind cargo in the bacterial cytosol, establishing protein interaction networks needed for effector translocation into host cells. In Salmonella enterica serovar Typhimurium, a T3SS encoded in a large genomic island (SPI-2) is required for intracellular infection, but the chaperone complement required for effector translocation by this system is not known. Using a reverse genetics approach, we identified a multi-cargo secretion chaperone that is functionally integrated with the SPI-2-encoded T3SS and required for systemic infection in mice. Crystallographic analysis of SrcA at a resolution of 2.5 A revealed a dimer similar to the CesT chaperone from enteropathogenic E. coli but lacking a 17-amino acid extension at the carboxyl terminus. Further biochemical and quantitative proteomics data revealed three protein interactions with SrcA, including two effector cargos (SseL and PipB2) and the type III-associated ATPase, SsaN, that increases the efficiency of effector translocation. Using competitive infections in mice we show that SrcA increases bacterial fitness during host infection, highlighting the in vivo importance of effector chaperones for the SPI-2 T3SS.

Microbe-independent entry of oomycete RxLR effectors and fungal RxLR-like effectors into plant and animal cells is specific and reproducible.

PubMed

Tyler, Brett M; Kale, Shiv D; Wang, Qunqing; Tao, Kai; Clark, Helen R; Drews, Kelly; Antignani, Vincenzo; Rumore, Amanda; Hayes, Tristan; Plett, Jonathan M; Fudal, Isabelle; Gu, Biao; Chen, Qinghe; Affeldt, Katharyn J; Berthier, Erwin; Fischer, Gregory J; Dou, Daolong; Shan, Weixing; Keller, Nancy P; Martin, Francis; Rouxel, Thierry; Lawrence, Christopher B

2013-06-01

A wide diversity of pathogens and mutualists of plant and animal hosts, including oomycetes and fungi, produce effector proteins that enter the cytoplasm of host cells. A major question has been whether or not entry by these effectors can occur independently of the microbe or requires machinery provided by the microbe. Numerous publications have documented that oomycete RxLR effectors and fungal RxLR-like effectors can enter plant and animal cells independent of the microbe. A recent reexamination of whether the RxLR domain of oomycete RxLR effectors is sufficient for microbe-independent entry into host cells concluded that the RxLR domains of Phytophthora infestans Avr3a and of P. sojae Avr1b alone are NOT sufficient to enable microbe-independent entry of proteins into host and nonhost plant and animal cells. Here, we present new, more detailed data that unambiguously demonstrate that the RxLR domain of Avr1b does show efficient and specific entry into soybean root cells and also into wheat leaf cells, at levels well above background nonspecific entry. We also summarize host cell entry experiments with a wide diversity of oomycete and fungal effectors with RxLR or RxLR-like motifs that have been independently carried out by the seven different labs that coauthored this letter. Finally we discuss possible technical reasons why specific cell entry may have been not detected by Wawra et al. (2013).

HMBPP-deficient Listeria mutant immunization alters pulmonary/systemic responses, effector functions, and memory polarization of Vγ2Vδ2 T cells

PubMed Central

Frencher, James T.; Shen, Hongbo; Yan, Lin; Wilson, Jessica O.; Freitag, Nancy E.; Rizzo, Alicia N.; Chen, Crystal Y.; Chen, Zheng W.

2014-01-01

Whereas infection or immunization of humans/primates with microbes coproducing HMBPP/IPP can remarkably activate Vγ2Vδ2 T cells, in vivo studies have not been done to dissect HMBPP- and IPP-driven expansion, pulmonary trafficking, effector functions, and memory polarization of Vγ2Vδ2 T cells. We define these phosphoantigen-host interplays by comparative immunizations of macaques with the HMBPP/IPP-coproducing Listeria ΔactA prfA* and HMBPP-deficient Listeria ΔactAΔgcpE prfA* mutant. The HMBPP-deficient ΔgcpE mutant shows lower ability to expand Vγ2Vδ2 T cells in vitro than the parental HMBPP-producing strain but displays comparably attenuated infectivity or immunogenicity. Respiratory immunization of macaques with the HMBPP-deficient mutant elicits lower pulmonary and systemic responses of Vγ2Vδ2 T cells compared with the HMBPP-producing vaccine strain. Interestingly, HMBPP-deficient mutant reimmunization or boosting elicits enhanced responses of Vγ2Vδ2 T cells, but the magnitude is lower than that by HMBPP-producing listeria. HMBPP-deficient listeria differentiated fewer Vγ2Vδ2 T effector cells capable of coproducing IFN-γ and TNF-α and inhibiting intracellular listeria than HMBPP-producing listeria. Furthermore, HMBPP deficiency in listerial immunization influences memory polarization of Vγ2Vδ2 T cells. Thus, both HMBPP and IPP production in listerial immunization or infection elicit systemic/pulmonary responses and differentiation of Vγ2Vδ2 T cells, but a role for HMBPP is more dominant. Findings may help devise immune intervention. PMID:25114162

IL-21 sustains CD28 expression on IL-15-activated human naive CD8+ T cells.

PubMed

Alves, Nuno L; Arosa, Fernando A; van Lier, René A W

2005-07-15

Human naive CD8+ T cells are able to respond in an Ag-independent manner to IL-7 and IL-15. Whereas IL-7 largely maintains CD8+ T cells in a naive phenotype, IL-15 drives these cells to an effector phenotype characterized, among other features, by down-regulation of the costimulatory molecule CD28. We evaluated the influence of the CD4+ Th cell-derived common gamma-chain cytokine IL-21 on cytokine-induced naive CD8+ T cell activation. Stimulation with IL-21 did not induce division and only slightly increased IL-15-induced proliferation of naive CD8+ T cells. Strikingly, however, IL-15-induced down-modulation of CD28 was completely prevented by IL-21 at the protein and transcriptional level. Subsequent stimulation via combined TCR/CD3 and CD28 triggering led to a markedly higher production of IL-2 and IFN-gamma in IL-15/IL-21-stimulated cells compared with IL-15-stimulated T cells. Our data show that IL-21 modulates the phenotype of naive CD8+ T cells that have undergone IL-15 induced homeostatic proliferation and preserves their responsiveness to CD28 ligands.

Experimental approaches to investigate effector translocation into host cells in the Ustilago maydis/maize pathosystem.

PubMed

Tanaka, Shigeyuki; Djamei, Armin; Presti, Libera Lo; Schipper, Kerstin; Winterberg, Sarah; Amati, Simone; Becker, Dirk; Büchner, Heike; Kumlehn, Jochen; Reissmann, Stefanie; Kahmann, Regine

2015-01-01

The fungus Ustilago maydis is a pathogen that establishes a biotrophic interaction with Zea mays. The interaction with the plant host is largely governed by more than 300 novel, secreted protein effectors, of which only four have been functionally characterized. Prerequisite to examine effector function is to know where effectors reside after secretion. Effectors can remain in the extracellular space, i.e. the plant apoplast (apoplastic effectors), or can cross the plant plasma membrane and exert their function inside the host cell (cytoplasmic effectors). The U. maydis effectors lack conserved motifs in their primary sequences that could allow a classification of the effectome into apoplastic/cytoplasmic effectors. This represents a significant obstacle in functional effector characterization. Here we describe our attempts to establish a system for effector classification into apoplastic and cytoplasmic members, using U. maydis for effector delivery. Copyright © 2015 Elsevier GmbH. All rights reserved.

[Allergic asthma and interleukins 2, 4, 5, 6 and 12 and gamma interferon levels].

PubMed

Bastida Segura, Diana Lyzbeth; López Velásquez, Benjamin; Castrejón Vázquez, María Isabel; Galicia Tapía, Jorge; Cano Altamirano, Silvia; Miranda Feria, Alfonso Javier

2004-01-01

Asthma is an inflammatory chronic illness, in which mastocyt cells, basophils, T lymphocytes, eosinophils and cytokines play a role. Its association with the production of TH2 cytokines is not well known, but it is considered an aberrant immune response, yielding the activation and recruitment of a number of effector cells (mastocyts/eosinophils) and the appearance of clinical symptoms. To determine the serum values of the interleukins 2, 4, 5, 6 and 12 and gamma interferon in relation to the severity degree of asthma and the time of immunotherapy in patients with stable chronic allergic bronchial asthma. Clinical records of allergic asthmatic patients from the external consultation at Servicio de Alergia e Immunología Clínica were reviewed in a period of 12 months (1st January 2002 to 1st January 2003) and those of healthy volunteers, forming three groups: Group 1, allergic asthmatics with immunotherapy less than 24 months; Group 2, allergic asthmatics with more than 24 months of immunotherapy, and Group 3, healthy volunteers (control group). Previous informed consent, a serum sample was taken of all subjects. Ninety-two subjects were included: 41 (45%) allergic asthmatics and 51 (55%) healthy volunteers. Significant differences were found in interleukins 2, 4, 5, 6 and 12 levels between healthy volunteers and asthmatics without relating the immunotherapy time. In the total group gamma interferon levels were not found. A relation of interleukins Th2 levels with the severity degree of asthma was not found. Differences of serum interleukins Th1 and Th2 in allergic patients related to immunotherapy time were not significant; even though, irrespective of immunotherapy time, IgG levels were always high. Patients with allergic asthma have a predominance of serum interleukins Th2 and, despite of the immunotherapy, in the maintaining phase, these continue high, which may be due to an immune system dysregulation maybe including other factors. Immunotherapy continues being one of the most useful specific treatments in allergic diseases, demonstrated by its satisfactory clinical response, reduced drugs' use and modification in severity and evolution of the disease.

Intrinsic disorder in pathogen effectors: protein flexibility as an evolutionary hallmark in a molecular arms race.

PubMed

Marín, Macarena; Uversky, Vladimir N; Ott, Thomas

2013-09-01

Effector proteins represent a refined mechanism of bacterial pathogens to overcome plants' innate immune systems. These modular proteins often manipulate host physiology by directly interfering with immune signaling of plant cells. Even if host cells have developed efficient strategies to perceive the presence of pathogenic microbes and to recognize intracellular effector activity, it remains an open question why only few effectors are recognized directly by plant resistance proteins. Based on in-silico genome-wide surveys and a reevaluation of published structural data, we estimated that bacterial effectors of phytopathogens are highly enriched in long-disordered regions (>50 residues). These structurally flexible segments have no secondary structure under physiological conditions but can fold in a stimulus-dependent manner (e.g., during protein-protein interactions). The high abundance of intrinsic disorder in effectors strongly suggests positive evolutionary selection of this structural feature and highlights the dynamic nature of these proteins. We postulate that such structural flexibility may be essential for (1) effector translocation, (2) evasion of the innate immune system, and (3) host function mimicry. The study of these dynamical regions will greatly complement current structural approaches to understand the molecular mechanisms of these proteins and may help in the prediction of new effectors.

CD4 T cell-mediated protection from lethal influenza: perforin and antibody-mediated mechanisms give a one-two punch.

PubMed

Brown, Deborah M; Dilzer, Allison M; Meents, Dana L; Swain, Susan L

2006-09-01

The mechanisms whereby CD4 T cells contribute to the protective response against lethal influenza infection remain poorly characterized. To define the role of CD4 cells in protection against a highly pathogenic strain of influenza, virus-specific TCR transgenic CD4 effectors were generated in vitro and transferred into mice given lethal influenza infection. Primed CD4 effectors conferred protection against lethal infection over a broad range of viral dose. The protection mediated by CD4 effectors did not require IFN-gamma or host T cells, but did result in increased anti-influenza Ab titers compared with untreated controls. Further studies indicated that CD4-mediated protection at high doses of influenza required B cells, and that passive transfer of anti-influenza immune serum was therapeutic in B cell-deficient mice, but only when CD4 effectors were present. Primed CD4 cells also acquired perforin (Pfn)-mediated cytolytic activity during effector generation, suggesting a second mechanism used by CD4 cells to confer protection. Pfn-deficient CD4 effectors were less able to promote survival in intact BALB/c mice and were unable to provide protection in B cell-deficient mice, indicating that Ab-independent protection by CD4 effectors requires Pfn. Therefore, CD4 effectors mediate protection to lethal influenza through at least two mechanisms: Pfn-mediated cytotoxicity early in the response promoted survival independently of Ab production, whereas CD4-driven B cell responses resulted in high titer Abs that neutralized remaining virus.

Pathogenic mechanisms of allergic inflammation: atopic asthma as a paradigm.

PubMed

Holt, Patrick G; Strickland, Deborah H; Bosco, Anthony; Jahnsen, Frode L

2009-01-01

Prospective studies tracking birth cohorts over periods of years indicate that the seeds for atopic asthma in adulthood are sewn during early life. The key events involve programming of functional phenotypes within the immune and respiratory systems which determine long-term responsiveness to ubiquitous environmental stimuli, particularly respiratory viruses and aeroallergens. A crucial component of asthma pathogenesis is early sensitization to aeroallergens stemming from a failure of mucosal tolerance mechanisms during the preschool years, which is associated with delayed postnatal maturation of a range of adaptive and innate immune functions. These maturational defects also increase risk for severe respiratory infections, and the combination of sensitization and infections maximizes risk for early development of the persistent asthma phenotype. Interactions between immunoinflammatory pathways stimulated by these agents also sustain the disease in later life as major triggers of asthma exacerbations. Recent studies on the nature of these interactions suggest the operation of an infection-associated lung:bone marrow axis involving upregulation of FcERlalpha on myeloid precursor populations prior to their migration to the airways, thus amplifying local inflammation via IgE-mediated recruitment of bystander atopic effector mechanisms. The key participants in the disease process are airway mucosal dendritic cells and adjacent epithelial cells, and transiting CD4(+) effector and regulatory T-cell populations, and increasingly detailed characterization of their roles at different stages of pathogenesis is opening up novel possibilities for therapeutic control of asthma. Of particular interest is the application of genomics-based approaches to drug target identification in cell populations of interest, exemplified by recent findings discussed below relating to the gene network(s) triggered by activation of Th2-memory cells from atopics. 2009 Elsevier Inc. All rights reserved.

Subcellular Localization of Pseudomonas syringae pv. tomato Effector Proteins in Plants.

PubMed

Aung, Kyaw; Xin, Xiufang; Mecey, Christy; He, Sheng Yang

2017-01-01

Animal and plant pathogenic bacteria use type III secretion systems to translocate proteinaceous effectors to subvert innate immunity of their host organisms. Type III secretion/effector systems are a crucial pathogenicity factor in many bacterial pathogens of plants and animals. Pseudomonas syringae pv. tomato (Pst) DC3000 injects a total of 36 protein effectors that target a variety of host proteins. Studies of a subset of Pst DC3000 effectors demonstrated that bacterial effectors, once inside the host cell, are localized to different subcellular compartments, including plasma membrane, cytoplasm, mitochondria, chloroplast, and Trans-Golgi network, to carry out their virulence functions. Identifying the subcellular localization of bacterial effector proteins in host cells could provide substantial clues to understanding the molecular and cellular basis of the virulence activities of effector proteins. In this chapter, we present methods for transient or stable expression of bacterial effector proteins in tobacco and/or Arabidopsis thaliana for live cell imaging as well as confirming the subcellular localization in plants using fluorescent organelle markers or chemical treatment.

Comprehensive Approach for Identifying the T Cell Subset Origin of CD3 and CD28 Antibody-Activated Chimeric Antigen Receptor-Modified T Cells.

PubMed

Schmueck-Henneresse, Michael; Omer, Bilal; Shum, Thomas; Tashiro, Haruko; Mamonkin, Maksim; Lapteva, Natalia; Sharma, Sandhya; Rollins, Lisa; Dotti, Gianpietro; Reinke, Petra; Volk, Hans-Dieter; Rooney, Cliona M

2017-07-01

The outcome of therapy with chimeric Ag receptor (CAR)-modified T cells is strongly influenced by the subset origin of the infused T cells. However, because polyclonally activated T cells acquire a largely CD45RO + CCR7 - effector memory phenotype after expansion, regardless of subset origin, it is impossible to know which subsets contribute to the final T cell product. To determine the contribution of naive T cell, memory stem T cell, central memory T cell, effector memory T cell, and terminally differentiated effector T cell populations to the CD3 and CD28-activated CAR-modified T cells that we use for therapy, we followed the fate and function of individually sorted CAR-modified T cell subsets after activation with CD3 and CD28 Abs (CD3/28), transduction and culture alone, or after reconstitution into the relevant subset-depleted population. We show that all subsets are sensitive to CAR transduction, and each developed a distinct T cell functional profile during culture. Naive-derived T cells showed the greatest rate of proliferation but had more limited effector functions and reduced killing compared with memory-derived populations. When cultured in the presence of memory T cells, naive-derived T cells show increased differentiation, reduced effector cytokine production, and a reduced reproliferative response to CAR stimulation. CD3/28-activated T cells expanded in IL-7 and IL-15 produced greater expansion of memory stem T cells and central memory T cell-derived T cells compared with IL-2. Our strategy provides a powerful tool to elucidate the characteristics of CAR-modified T cells, regardless of the protocol used for expansion, reveals the functional properties of each expanded T cell subset, and paves the way for a more detailed evaluation of the effects of manufacturing changes on the subset contribution to in vitro-expanded T cells. Copyright © 2017 by The American Association of Immunologists, Inc.

Antigen-specific, CD4+CD25+ regulatory T cell clones induced in Peyer's patches.

PubMed

Tsuji, Noriko M; Mizumachi, Koko; Kurisaki, Jun-Ichi

2003-04-01

Since intestine is exposed to numerous exogenous antigens such as food and commensal bacteria, the organ bears efficient mechanisms for establishment of tolerance and induction of regulatory T cells (T(reg)). Intestinal and inducible T(reg) include T(r)1-like and T(h)3 cells whose major effector molecules are IL-10 and transforming growth factor (TGF)-beta. These antigen-specific T(reg) are expected to become clinical targets to modify the inflammatory immune response associated with allergy, autoimmune diseases and transplantation. In the present study, we characterized the antigen-specific T(reg) induced in the intestine by orally administering high-dose beta-lactoglobulin (BLG) to BALB/c mice. Seven days after feeding, only Peyer's patch (PP) cells among different organs exerted significant suppressive effect on antibody production upon in vitro BLG stimulation. This suppressive effect was also prominent in six BLG-specific CD4(+) T cell clones (OPP1-6) established from PP from mice orally administered with high doses of BLG and was partially reversed by antibodies to TGF-beta. Intravenous transfer of OPP2 efficiently suppressed BLG-specific IgG1 production in serum following immunization, indicating the role of such T(reg) in the systemic tolerance after oral administration of antigen (oral tolerance). OPP clones secrete TGF-beta, IFN-gamma and low levels of IL-10, a cytokine pattern similar to that secreted by anergic T cells. OPP clones bear a CD4(+)CD25(+) phenotype and show significantly lower proliferative response compared to T(h)0 clones. This lower response is recovered by the addition of IL-2. Thus, antigen-specific CD4(+)CD25(+) T(reg), which have characteristics of anergic cells and actively suppress antibody production are induced in PP upon oral administration of protein antigen.

Legionella and Coxiella effectors: strength in diversity and activity.

PubMed

Qiu, Jiazhang; Luo, Zhao-Qing

2017-10-01

Legionella pneumophila and Coxiella burnetii are two evolutionarily related intracellular pathogens that use the Dot/Icm type IV secretion system to translocate effectors into host cells. These effectors are essential for the establishment of membrane-bound compartments known as replication vacuoles, which enable the survival and replication of bacteria inside host cells. The effectors interfere with diverse signalling pathways to co-opt host processes, such as vesicle trafficking, ubiquitylation, gene expression and lipid metabolism, to promote pathogen survival. In this Review, we explore Dot/Icm effectors from L. pneumophila and C. burnetii as key virulence factors, and we examine the biochemical and cell biological functions of these effectors and their roles in our understanding of bacterial virulence.

Diverse Class 2 CRISPR-Cas Effector Proteins for Genome Engineering Applications.

PubMed

Pyzocha, Neena K; Chen, Sidi

2018-02-16

CRISPR-Cas genome editing technologies have revolutionized modern molecular biology by making targeted DNA edits simple and scalable. These technologies are developed by domesticating naturally occurring microbial adaptive immune systems that display wide diversity of functionality for targeted nucleic acid cleavage. Several CRISPR-Cas single effector enzymes have been characterized and engineered for use in mammalian cells. The unique properties of the single effector enzymes can make a critical difference in experimental use or targeting specificity. This review describes known single effector enzymes and discusses their use in genome engineering applications.

Curtailed T-cell activation curbs effector differentiation and generates CD8+ T cells with a naturally-occurring memory stem cell phenotype.

PubMed

Zanon, Veronica; Pilipow, Karolina; Scamardella, Eloise; De Paoli, Federica; De Simone, Gabriele; Price, David A; Martinez Usatorre, Amaia; Romero, Pedro; Mavilio, Domenico; Roberto, Alessandra; Lugli, Enrico

2017-09-01

Human T memory stem (T SCM ) cells with superior persistence capacity and effector functions are emerging as important players in the maintenance of long-lived T-cell memory and are thus considered an attractive population to be used in adoptive transfer-based immunotherapy of cancer. However, the molecular signals regulating their generation remain poorly defined. Here we show that curtailed T-cell receptor stimulation curbs human effector CD8 + T-cell differentiation and allows the generation of CD45RO - CD45RA + CCR7 + CD27 + CD95 + -phenotype cells from highly purified naïve T-cell precursors, resembling naturally-occurring human T SCM . These cells proliferate extensively in vitro and in vivo, express low amounts of effector-associated genes and transcription factors and undergo considerable self-renewal in response to IL-15 while retaining effector differentiation potential. Such a phenotype is associated with a lower number of mitochondria compared to highly-activated effector T cells committed to terminal differentiation. These results shed light on the molecular signals that are required to generate long-lived memory T cells with potential application in adoptive cell transfer immunotherapy. © 2017 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co.KGaA, Weinheim.

Allogeneic killing by earthworm effector cells.

PubMed

Suzuki, M M; Cooper, E L

1995-01-01

We observed spontaneous allogeneic cytotoxicity by coelomocytes (Lumbricus terrestris) using three assays: trypan blue, lactate dehydrogenase release and chromium-51 release. Cell-cell contact may not be essential to effect cytotoxicity, since killing of allogeneic cells occurred in pooled allogeneic coelomic fluid derived from worms raised in two different geographic locales. We observed no significant spontaneous cytotoxicity against autogeneic target coelomocytes haptenated with 2,4,6-trinitrobenzene sulfonic acid; however, coelomocytes effected significant spontaneous cytotoxicity against haptenated allogeneic targets. These results support the view that earthworm coelomocytes can act as effector cells that can specifically kill nonself target cells.

Activation-Induced Killer Cell Immunoglobulin-like Receptor 3DL2 Binding to HLA-B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis.

PubMed

Ridley, Anna; Hatano, Hiroko; Wong-Baeza, Isabel; Shaw, Jacqueline; Matthews, Katherine K; Al-Mossawi, Hussein; Ladell, Kristin; Price, David A; Bowness, Paul; Kollnberger, Simon

2016-04-01

In the spondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin-like receptor 3DL2 (KIR-3DL2). The aim of this study was to determine the factors that induce KIR-3DL2 expression, and to characterize the relationship between HLA-B27 and the phenotype and function of KIR-3DL2-expressing CD4+ T cells in SpA. In total, 34 B27+ patients with SpA, 28 age- and sex-matched healthy controls (20 B27- and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template-switch anchored reverse transcription-polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme-linked immunosorbent assay. Cellular activation induced KIR-3DL2 expression on both naive and effector CD4+ T cells. KIR-3DL2 binding to B27+ cells promoted expression of KIR-3DL2, the Th17-specific transcription factor retinoic acid receptor-related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR-3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen-presenting cells, KIR-3DL2+CD4+ T cells produced less interleukin-2 (IL-2) but more IL-17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR-3DL2 to B27 heavy chains. KIR-3DL2 binding to HLA-B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA-B27-KIR-3DL2 interactions for the treatment of B27+ patients with SpA. © 2016 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.

Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen, Legionella pneumophila.

PubMed

Urbanus, Malene L; Quaile, Andrew T; Stogios, Peter J; Morar, Mariya; Rao, Chitong; Di Leo, Rosa; Evdokimova, Elena; Lam, Mandy; Oatway, Christina; Cuff, Marianne E; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw P; Taipale, Mikko; Savchenko, Alexei; Ensminger, Alexander W

2016-12-16

Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector-effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector-effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila-translocated substrates. While capturing all known examples of effector-effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct-a hallmark of an emerging class of proteins called metaeffectors, or "effectors of effectors". Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector-effector modulation, may be a common feature of many intracellular pathogens-with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

Cytokine and Lipid Mediator Regulation of Group 2 Innate Lymphoid Cells (ILC2s) in Human Allergic Airway Disease.

PubMed

Cavagnero, Kellen; Doherty, Taylor A

2017-08-01

The recent discovery of group 2 innate lymphoid cells (ILC2s) has caused a paradigm shift in the understanding of allergic airway disease pathogenesis. Prior to the discovery of ILC2s, Th2 cells were largely thought to be the primary source of type 2 cytokines; however, activated ILC2s have since been shown to contribute significantly, and in some cases, dominantly to type 2 cytokine production. Since the discovery of ILC2s in 2010, many mediators have been shown to regulate their effector functions. Initial studies identified the epithelial derived cytokines IL-25, IL-33, and TSLP as activators of ILC2s, and recent studies have identified many additional cytokine and lipid mediators that are involved in ILC2 regulation. ILC2s and their mediators represent novel therapeutic targets for allergic airway diseases and intensive investigation is underway to better understand ILC2 biology and upstream and downstream pathways that lead to ILC2-driven airway pathology. In this review, we will focus on the cytokine and lipid mediators that regulate ILC2s in human allergic airway disease, as well as highlight newly discovered mediators of mouse ILC2s that may eventually translate to humans.

Autoreactive T effector memory differentiation mirrors β-cell function in type 1 diabetes.

PubMed

Yeo, Lorraine; Woodwyk, Alyssa; Sood, Sanjana; Lorenc, Anna; Eichmann, Martin; Pujol-Autonell, Irma; Melchiotti, Rossella; Skowera, Ania; Fidanis, Efthymios; Dolton, Garry M; Tungatt, Katie; Sewell, Andrew K; Heck, Susanne; Saxena, Alka; Beam, Craig A; Peakman, Mark

2018-05-31

In type 1 diabetes, cytotoxic CD8 T cells with specificity for β-cell autoantigens are found in the pancreatic islets where they are implicated in the destruction of insulin-secreting β cells. In contrast, the disease relevance of β-cell-reactive CD8 T cells that are detectable in the circulation, and their relationship to β-cell function, are not known. Here, we tracked multiple, circulating β-cell-reactive CD8 T cell subsets and measured β-cell function longitudinally for two years, starting immediately after diagnosis of type 1 diabetes. We found that change in β-cell-specific effector memory CD8 T cells expressing CD57 was positively correlated with C-peptide change in subjects below 12 years of age. Autoreactive CD57+ effector memory CD8 T cells bore the signature of enhanced effector function (higher expression of granzyme B, killer specific protein 37 and CD16, and reduced expression of CD28) compared with their CD57-negative counterparts, and network association modelling indicated that the dynamics of β-cell-reactive CD57+ effector memory CD8 T cell subsets were strongly linked. Thus, coordinated changes in circulating β-cell-specific CD8 T cells within the CD57+ effector memory subset calibrate to functional insulin reserve in type 1 diabetes, providing a tool for immune monitoring and a mechanism-based target for immunotherapy.

IL-12 is required for differentiation of pathogenic CD8+ T cell effectors that cause myocarditis

PubMed Central

Grabie, Nir; Delfs, Michael W.; Westrich, Jason R.; Love, Victoria A.; Stavrakis, George; Ahmad, Ferhaan; Seidman, Christine E.; Seidman, Jonathan G.; Lichtman, Andrew H.

2003-01-01

Cardiac antigen–specific CD8+ T cells are involved in the autoimmune component of human myocarditis. Here, we studied the differentiation and migration of pathogenic CD8+ T cell effector cells in a new mouse model of autoimmune myocarditis. A transgenic mouse line was derived that expresses cardiac myocyte restricted membrane-bound ovalbumin (CMy-mOva). The endogenous adaptive immune system of CMy-mOva mice displays tolerance to ovalbumin. Adoptive transfer of naive CD8+ T cells from the ovalbumin-specific T cell receptor–transgenic (TCR-transgenic) OT-I strain induces myocarditis in CMy-mOva mice only after subsequent inoculation with ovalbumin-expressing vesicular stomatitis virus (VSV-Ova). OT-I effector T cells derived in vitro in the presence or absence of IL-12 were adoptively transferred into CMy-mOva mice, and the consequences were compared. Although IL-12 was not required for the generation of cytolytic and IFN-γ–producing effector T cells, only effectors primed in the presence of IL-12 infiltrated CMy-mOva hearts in significant numbers, causing lethal myocarditis. Furthermore, analysis of OT-I effectors collected from a mediastinal draining lymph node indicated that only effectors primed in vitro in the presence of IL-12 proliferated in vivo. These data demonstrate the importance of IL-12 in the differentiation of pathogenic CD8+ T cells that can cause myocarditis. PMID:12618521

HIV-Infected Children Have Lower Frequencies of CD8+ Mucosal-Associated Invariant T (MAIT) Cells that Correlate with Innate, Th17 and Th22 Cell Subsets

PubMed Central

Kilberg, Max; Kravietz, Adam; Ilmet, Tiina; Tastan, Cihan; Mwamzuka, Mussa; Marshed, Fatma; Liu, Mengling; Ahmed, Aabid; Borkowsky, William; Unutmaz, Derya

2016-01-01

Mucosal-associated invariant T cells (MAIT) are innate T cells restricted by major histocompatibility related molecule 1 (MR1) presenting riboflavin metabolite ligands derived from microbes. Specificity to riboflavin metabolites confers MAIT cells a broad array of host-protective activity against gram-negative and -positive bacteria, mycobacteria, and fungal pathogens. MAIT cells are present at low levels in the peripheral blood of neonates and gradually expand to relatively abundant levels during childhood. Despite no anti-viral activity, MAIT cells are depleted early and irreversibly in HIV infected adults. Such loss or impaired expansion of MAIT cells in HIV-positive children may render them more susceptible to common childhood illnesses and opportunistic infections. In this study we evaluated the frequency of MAIT cells in perinatally HIV-infected children, their response to antiretroviral treatment and their associations with HIV clinical status and related innate and adaptive immune cell subsets with potent antibacterial effector functions. We found HIV+ children between ages 3 to 18 years have significantly decreased CD8+ MAIT cell frequencies compared to uninfected healthy children. Remarkably, CD8 MAIT levels gradually increased with antiretroviral therapy, with greater recovery when treatment is initiated at a young age. Moreover, diminished CD8+ MAIT cell frequencies are associated with low CD4:CD8 ratios and elevated sCD14, suggesting a link with HIV disease progression. Last, CD8+ MAIT cell levels tightly correlate with other antibacterial and mucosa-protective immune subsets, namely, neutrophils, innate-like T cells, and Th17 and Th22 cells. Together these findings suggest that low frequencies of MAIT cells in HIV positive children are part of a concerted disruption to the innate and adaptive immune compartments specialized in sensing and responding to pathogenic or commensal bacteria. PMID:27560150

Identification and characterization of suppressors of plant cell death (SPD) effectors from Magnaporthe oryzae.

PubMed

Sharpee, William; Oh, Yeonyee; Yi, Mihwa; Franck, William; Eyre, Alex; Okagaki, Laura H; Valent, Barbara; Dean, Ralph A

2017-08-01

Phytopathogenic microorganisms, including the fungal pathogen Magnaporthe oryzae, secrete a myriad of effector proteins to facilitate infection. Utilizing the transient expression of candidate effectors in the leaves of the model plant Nicotiana benthamiana, we identified 11 suppressors of plant cell death (SPD) effectors from M. oryzae that were able to block the host cell death reaction induced by Nep1. Ten of these 11 were also able to suppress BAX-mediated plant cell death. Five of the 11 SPD genes have been identified previously as either essential for the pathogenicity of M. oryzae, secreted into the plant during disease development, or as suppressors or homologues of other characterized suppressors. In addition, of the remaining six, we showed that SPD8 (previously identified as BAS162) was localized to the rice cytoplasm in invaded and surrounding uninvaded cells during biotrophic invasion. Sequence analysis of the 11 SPD genes across 43 re-sequenced M. oryzae genomes revealed that SPD2, SPD4 and SPD7 have nucleotide polymorphisms amongst the isolates. SPD4 exhibited the highest level of nucleotide diversity of any currently known effector from M. oryzae in addition to the presence/absence polymorphisms, suggesting that this gene is potentially undergoing selection to avoid recognition by the host. Taken together, we have identified a series of effectors, some of which were previously unknown or whose function was unknown, that probably act at different stages of the infection process and contribute to the virulence of M. oryzae. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Developmental Regulation of Effector and Resident Memory T Cell Generation during Pediatric Viral Respiratory Tract Infection.

PubMed

Connors, Thomas J; Baird, J Scott; Yopes, Margot C; Zens, Kyra D; Pethe, Kalpana; Ravindranath, Thyyar M; Ho, Siu-Hong; Farber, Donna L

2018-05-30

Viral respiratory tract infections (VRTI) remain a leading cause of morbidity and mortality among infants and young children. In mice, optimal protection to VRTI is mediated by recruitment of effector T cells to the lungs and respiratory tract, and subsequent establishment of tissue resident memory T cells (Trm), which provide long-term protection. These critical processes of T cell recruitment to the respiratory tract, their role in disease pathogenesis, and establishment of local protective immunity remain undefined in pediatric VRTI. In this study, we investigated T cell responses in the upper respiratory tract (URT) and lower respiratory tract (LRT) of infants and young children with VRTI, revealing developmental regulation of T cell differentiation and Trm generation in situ. We show a direct concurrence between T cell responses in the URT and LRT, including a preponderance of effector CD8 + T cells that was associated with disease severity. During infant VRTI, there was an accumulation of terminally differentiated effector cells (effector memory RA + T cells) in the URT and LRT with reduced Trm in the early neonatal period, and decreased effector memory RA + T cell and increased Trm formation with age during the early years of childhood. Moreover, human infant T cells exhibit increased expression of the transcription factor T-bet compared with adult T cells, suggesting a mechanism for preferential generation of effector over Trm. The developmental regulation of respiratory T cell responses as revealed in the present study is important for diagnosing, monitoring, and treating VRTI in the critical early life stages. Copyright © 2018 by The American Association of Immunologists, Inc.

The Transcription Factor T-Bet Is Regulated by MicroRNA-155 in Murine Anti-Viral CD8+ T Cells via SHIP-1.

PubMed

Hope, Jennifer L; Stairiker, Christopher J; Spantidea, Panagiota I; Gracias, Donald T; Carey, Alison J; Fike, Adam J; van Meurs, Marjan; Brouwers-Haspels, Inge; Rijsbergen, Laurine C; Fraietta, Joseph A; Mueller, Yvonne M; Klop, Rosemarieke C; Stelekati, Erietta; Wherry, E John; Erkeland, Stefan J; Katsikis, Peter D

2017-01-01

We report here that the expression of the transcription factor T-bet, which is known to be required for effector cytotoxic CD8 + T lymphocytes (CTL) generation and effector memory cell formation, is regulated in CTL by microRNA-155 (miR-155). Importantly, we show that the proliferative effect of miR-155 on CD8 + T cells is mediated by T-bet. T-bet levels in CTL were controlled in vivo by miR-155 via SH2 (Src homology 2)-containing inositol phosphatase-1 (SHIP-1), a known direct target of miR-155, and SHIP-1 directly downregulated T-bet. Our studies reveal an important and unexpected signaling axis between miR-155, T-bet, and SHIP-1 in in vivo CTL responses and suggest an important signaling module that regulates effector CTL immunity.

Multiple Xanthomonas euvesicatoria Type III Effectors Inhibit flg22-Triggered Immunity.

PubMed

Popov, Georgy; Fraiture, Malou; Brunner, Frederic; Sessa, Guido

2016-08-01

Xanthomonas euvesicatoria is the causal agent of bacterial spot disease in pepper and tomato. X. euvesicatoria bacteria interfere with plant cellular processes by injecting effector proteins into host cells through the type III secretion (T3S) system. About 35 T3S effectors have been identified in X. euvesicatoria 85-10, and a few of them were implicated in suppression of pattern-triggered immunity (PTI). We used an Arabidopsis thaliana pathogen-free protoplast-based assay to identify X. euvesicatoria 85-10 effectors that interfere with PTI signaling induced by the bacterial peptide flg22. Of 33 tested effectors, 17 inhibited activation of a PTI-inducible promoter. Among them, nine effectors also interfered with activation of an abscisic acid-inducible promoter. However, effectors that inhibited flg22-induced signaling did not affect phosphorylation of mitogen-activated protein (MAP) kinases acting downstream of flg22 perception. Further investigation of selected effectors revealed that XopAJ, XopE2, and XopF2 inhibited activation of a PTI-inducible promoter by the bacterial peptide elf18 in Arabidopsis protoplasts and by flg22 in tomato protoplasts. The effectors XopF2, XopE2, XopAP, XopAE, XopH, and XopAJ inhibited flg22-induced callose deposition in planta and enhanced disease symptoms caused by attenuated Pseudomonas syringae bacteria. Finally, selected effectors were found to localize to various plant subcellular compartments. These results indicate that X. euvesicatoria bacteria utilize multiple T3S effectors to suppress flg22-induced signaling acting downstream or in parallel to MAP kinase cascades and suggest they act through different molecular mechanisms.

Progressive CD4+ central memory T cell decline results in CD4+ effector memory insufficiency and overt disease in chronic SIV infection.

PubMed

Okoye, Afam; Meier-Schellersheim, Martin; Brenchley, Jason M; Hagen, Shoko I; Walker, Joshua M; Rohankhedkar, Mukta; Lum, Richard; Edgar, John B; Planer, Shannon L; Legasse, Alfred; Sylwester, Andrew W; Piatak, Michael; Lifson, Jeffrey D; Maino, Vernon C; Sodora, Donald L; Douek, Daniel C; Axthelm, Michael K; Grossman, Zvi; Picker, Louis J

2007-09-03

Primary simian immunodeficiency virus (SIV) infections of rhesus macaques result in the dramatic depletion of CD4(+) CCR5(+) effector-memory T (T(EM)) cells from extra-lymphoid effector sites, but in most infections, an increased rate of CD4(+) memory T cell proliferation appears to prevent collapse of effector site CD4(+) T(EM) cell populations and acute-phase AIDS. Eventually, persistent SIV replication results in chronic-phase AIDS, but the responsible mechanisms remain controversial. Here, we demonstrate that in the chronic phase of progressive SIV infection, effector site CD4(+) T(EM) cell populations manifest a slow, continuous decline, and that the degree of this depletion remains a highly significant correlate of late-onset AIDS. We further show that due to persistent immune activation, effector site CD4(+) T(EM) cells are predominantly short-lived, and that their homeostasis is strikingly dependent on the production of new CD4(+) T(EM) cells from central-memory T (T(CM)) cell precursors. The instability of effector site CD4(+) T(EM) cell populations over time was not explained by increasing destruction of these cells, but rather was attributable to progressive reduction in their production, secondary to decreasing numbers of CCR5(-) CD4(+) T(CM) cells. These data suggest that although CD4(+) T(EM) cell depletion is a proximate mechanism of immunodeficiency, the tempo of this depletion and the timing of disease onset are largely determined by destruction, failing production, and gradual decline of CD4(+) T(CM) cells.

The Fusarium oxysporum effector Six6 contributes to virulence and suppresses I-2-mediated cell death.

PubMed

Gawehns, F; Houterman, P M; Ichou, F Ait; Michielse, C B; Hijdra, M; Cornelissen, B J C; Rep, M; Takken, F L W

2014-04-01

Plant pathogens secrete effectors to manipulate their host and facilitate colonization. Fusarium oxysporum f. sp. lycopersici is the causal agent of Fusarium wilt disease in tomato. Upon infection, F. oxysporum f. sp. lycopersici secretes numerous small proteins into the xylem sap (Six proteins). Most Six proteins are unique to F. oxysporum, but Six6 is an exception; a homolog is also present in two Colletotrichum spp. SIX6 expression was found to require living host cells and a knockout of SIX6 in F. oxysporum f. sp. lycopersici compromised virulence, classifying it as a genuine effector. Heterologous expression of SIX6 did not affect growth of Agrobacterium tumefaciens in Nicotiana benthamiana leaves or susceptibility of Arabidopsis thaliana toward Verticillium dahliae, Pseudomonas syringae, or F. oxysporum, suggesting a specific function for F. oxysporum f. sp. lycopersici Six6 in the F. oxysporum f. sp. lycopersici- tomato pathosystem. Remarkably, Six6 was found to specifically suppress I-2-mediated cell death (I2CD) upon transient expression in N. benthamiana, whereas it did not compromise the activity of other cell-death-inducing genes. Still, this I2CD suppressing activity of Six6 does not allow the fungus to overcome I-2 resistance in tomato, suggesting that I-2-mediated resistance is independent from cell death.

Oomycetes, effectors, and all that jazz.

PubMed

Bozkurt, Tolga O; Schornack, Sebastian; Banfield, Mark J; Kamoun, Sophien

2012-08-01

Plant pathogenic oomycetes secrete a diverse repertoire of effector proteins that modulate host innate immunity and enable parasitic infection. Understanding how effectors evolve, translocate and traffic inside host cells, and perturb host processes are major themes in the study of oomycete-plant interactions. The last year has seen important progress in the study of oomycete effectors with, notably, the elucidation of the 3D structures of five RXLR effectors, and novel insights into how cytoplasmic effectors subvert host cells. In this review, we discuss these and other recent advances and highlight the most important open questions in oomycete effector biology. Copyright © 2012 Elsevier Ltd. All rights reserved.

MYR1-Dependent Effectors Are the Major Drivers of a Host Cell's Early Response to Toxoplasma, Including Counteracting MYR1-Independent Effects.

PubMed

Naor, Adit; Panas, Michael W; Marino, Nicole; Coffey, Michael J; Tonkin, Christopher J; Boothroyd, John C

2018-04-03

The obligate intracellular parasite Toxoplasma gondii controls its host cell from within the parasitophorous vacuole (PV) by using a number of diverse effector proteins, a subset of which require the aspartyl protease 5 enzyme (ASP5) and/or the recently discovered MYR1 protein to cross the PV membrane. To examine the impact these effectors have in the context of the entirety of the host response to Toxoplasma , we used RNA-Seq to analyze the transcriptome expression profiles of human foreskin fibroblasts infected with wild-type RH (RH-WT), RHΔ myr1 , and RHΔ asp5 tachyzoites. Interestingly, the majority of the differentially regulated genes responding to Toxoplasma infection are MYR1 dependent. A subset of MYR1 responses were ASP5 independent, and MYR1 function did not require ASP5 cleavage, suggesting the export of some effectors requires only MYR1. Gene set enrichment analysis of MYR1-dependent host responses suggests an upregulation of E2F transcription factors and the cell cycle and a downregulation related to interferon signaling, among numerous others. Most surprisingly, "hidden" responses arising in RHΔ myr1 - but not RH-WT-infected host cells indicate counterbalancing actions of MYR1-dependent and -independent activities. The host genes and gene sets revealed here to be MYR1 dependent provide new insight into the parasite's ability to co-opt host cell functions. IMPORTANCE Toxoplasma gondii is unique in its ability to successfully invade and replicate in a broad range of host species and cells within those hosts. The complex interplay of effector proteins exported by Toxoplasma is key to its success in co-opting the host cell to create a favorable replicative niche. Here we show that a majority of the transcriptomic effects in tachyzoite-infected cells depend on the activity of a novel translocation system involving MYR1 and that the effectors delivered by this system are part of an intricate interplay of activators and suppressors. Removal of all MYR1-dependent effectors reveals previously unknown activities that are masked or hidden by the action of these proteins. Copyright © 2018 Naor et al.

Anti-leukemic activity and tolerability of anti-human CD47 monoclonal antibodies

PubMed Central

Pietsch, E C; Dong, J; Cardoso, R; Zhang, X; Chin, D; Hawkins, R; Dinh, T; Zhou, M; Strake, B; Feng, P-H; Rocca, M; Santos, C Dos; Shan, X; Danet-Desnoyers, G; Shi, F; Kaiser, E; Millar, H J; Fenton, S; Swanson, R; Nemeth, J A; Attar, R M

2017-01-01

CD47, a broadly expressed cell surface protein, inhibits cell phagocytosis via interaction with phagocyte-expressed SIRPα. A variety of hematological malignancies demonstrate elevated CD47 expression, suggesting that CD47 may mediate immune escape. We discovered three unique CD47-SIRPα blocking anti-CD47 monoclonal antibodies (mAbs) with low nano-molar affinity to human and cynomolgus monkey CD47, and no hemagglutination and platelet aggregation activity. To characterize the anti-cancer activity elicited by blocking CD47, the mAbs were cloned into effector function silent and competent Fc backbones. Effector function competent mAbs demonstrated potent activity in vitro and in vivo, while effector function silent mAbs demonstrated minimal activity, indicating that blocking CD47 only leads to a therapeutic effect in the presence of Fc effector function. A non-human primate study revealed that the effector function competent mAb IgG1 C47B222-(CHO) decreased red blood cells (RBC), hematocrit and hemoglobin by >40% at 1 mg/kg, whereas the effector function silent mAb IgG2σ C47B222-(CHO) had minimal impact on RBC indices at 1 and 10 mg/kg. Taken together, our findings suggest that targeting CD47 is an attractive therapeutic anti-cancer approach. However, the anti-cancer activity observed with anti-CD47 mAbs is Fc effector dependent as are the side effects observed on RBC indices. PMID:28234345

Depigmented-polymerised allergoids favour regulatory over effector T cells: enhancement by 1α, 25-dihydroxyvitamin D3.

PubMed

Urry, Zoe L; Richards, David F; Black, Cheryl; Morales, Maria; Carnés, Jerónimo; Hawrylowicz, Catherine M; Robinson, Douglas S

2014-05-29

Allergen immunotherapy (SIT) is the only treatment for allergic disease capable of modifying disease long term. To reduce the risk of anaphylaxis from SIT, allergen-extracts have been modified by polymerisation with glutaraldehyde to reduce IgE binding. It is suggested that these allergoid extracts also have reduced T cell activity, which could compromise clinical efficacy. Effective SIT is thought to act through regulatory T cells (Tregs) rather than activation of effector T cells. There is no published data on the activity of modified extracts on Tregs. We compared the capacity of modified (depigmented-polymerised) versus unmodified (native) allergen extracts of grass pollen and house dust mite to stimulate proliferation/cytokine production and to modulate Treg/effector T cell frequency in cultures of peripheral blood mononuclear cells (PBMC), from volunteers sensitised to both allergens in vitro. Depigmented-polymerised allergen extracts stimulated less proliferation of PBMC, and reduced effector cell numbers after 7 days in culture than did native extracts. However, the frequency of Foxp3+ Tregs in cultures were similar to those seen with native extract so that ratios of regulatory to effector T cells were significantly increased in cultures stimulated with depigmented-polymerised extracts. Addition of 1α, 25-dihydroxyvitamin D3 further favoured Treg, and reduced effector cytokine production, but not interleukin-10. Depigmented-polymerised allergen extracts appear to favour Treg expansion over activation of effector T cells and this may relate to their demonstrated efficacy and safety in SIT. 1α, 25-dihydroxyvitamin D3 further reduces effector T cell activation by allergen extracts and may be a useful adjuvant for SIT.

Depigmented-polymerised allergoids favour regulatory over effector T cells: enhancement by 1α, 25-dihydroxyvitamin D3

PubMed Central

2014-01-01

Background Allergen immunotherapy (SIT) is the only treatment for allergic disease capable of modifying disease long term. To reduce the risk of anaphylaxis from SIT, allergen-extracts have been modified by polymerisation with glutaraldehyde to reduce IgE binding. It is suggested that these allergoid extracts also have reduced T cell activity, which could compromise clinical efficacy. Effective SIT is thought to act through regulatory T cells (Tregs) rather than activation of effector T cells. There is no published data on the activity of modified extracts on Tregs. Results We compared the capacity of modified (depigmented-polymerised) versus unmodified (native) allergen extracts of grass pollen and house dust mite to stimulate proliferation/cytokine production and to modulate Treg/effector T cell frequency in cultures of peripheral blood mononuclear cells (PBMC), from volunteers sensitised to both allergens in vitro. Depigmented-polymerised allergen extracts stimulated less proliferation of PBMC, and reduced effector cell numbers after 7 days in culture than did native extracts. However, the frequency of Foxp3+ Tregs in cultures were similar to those seen with native extract so that ratios of regulatory to effector T cells were significantly increased in cultures stimulated with depigmented-polymerised extracts. Addition of 1α, 25-dihydroxyvitamin D3 further favoured Treg, and reduced effector cytokine production, but not interleukin-10. Conclusions Depigmented-polymerised allergen extracts appear to favour Treg expansion over activation of effector T cells and this may relate to their demonstrated efficacy and safety in SIT. 1α, 25-dihydroxyvitamin D3 further reduces effector T cell activation by allergen extracts and may be a useful adjuvant for SIT. PMID:24884430

E2~Ub conjugates regulate the kinase activity of Shigella effector OspG during pathogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pruneda, Jonathan N.; Smith, F. Donelson; Daurie, Angela

Pathogenic bacteria introduce effector proteins directly into the cytosol of eukaryotic cells to promote invasion and colonization. OspG, a Shigella spp. effector kinase, plays a role in this process by helping to suppress the host inflammatory response. OspG has been reported to bind host E2 ubiquitin-conjugating enzymes activated with ubiquitin (E2~Ub), a key enzyme complex in ubiquitin transfer pathways. A cocrystal structure of the OspG/UbcH5c~Ub complex reveals that complex formation has important ramifications for the activity of both OspG and the UbcH5c~Ub conjugate. OspG is a minimal kinase domain containing only essential elements required for catalysis. UbcH5c~Ub binding stabilizes anmore » active conformation of the kinase, greatly enhancing OspG kinase activity. In contrast, interaction with OspG stabilizes an extended, less reactive form of UbcH5c~Ub. Recognizing conserved E2 features, OspG can interact with at least ten distinct human E2s~Ub. Mouse oral infection studies indicate that E2~Ub conjugates act as novel regulators of OspG effector kinase function in eukaryotic host cells.« less

Potent Immune Modulation by MEDI6383, an Engineered Human OX40 Ligand IgG4P Fc Fusion Protein.

PubMed

Oberst, Michael D; Augé, Catherine; Morris, Chad; Kentner, Stacy; Mulgrew, Kathy; McGlinchey, Kelly; Hair, James; Hanabuchi, Shino; Du, Qun; Damschroder, Melissa; Feng, Hui; Eck, Steven; Buss, Nicholas; de Haan, Lolke; Pierce, Andrew J; Park, Haesun; Sylwester, Andrew; Axthelm, Michael K; Picker, Louis; Morris, Nicholas P; Weinberg, Andrew; Hammond, Scott A

2018-05-01

Ligation of OX40 (CD134, TNFRSF4) on activated T cells by its natural ligand (OX40L, CD252, TNFSF4) enhances cellular survival, proliferation, and effector functions such as cytokine release and cellular cytotoxicity. We engineered a recombinant human OX40L IgG4P Fc fusion protein termed MEDI6383 that assembles into a hexameric structure and exerts potent agonist activity following engagement of OX40. MEDI6383 displayed solution-phase agonist activity that was enhanced when the fusion protein was clustered by Fc gamma receptors (FcγRs) on the surface of adjacent cells. The resulting costimulation of OX40 on T cells induced NFκB promoter activity in OX40-expressing T cells and induced Th1-type cytokine production, proliferation, and resistance to regulatory T cell (Treg)-mediated suppression. MEDI6383 enhanced the cytolytic activity of tumor-reactive T cells and reduced tumor growth in the context of an alloreactive human T cell:tumor cell admix model in immunocompromised mice. Consistent with the role of OX40 costimulation in the expansion of memory T cells, MEDI6383 administered to healthy nonhuman primates elicited peripheral blood CD4 and CD8 central and effector memory T-cell proliferation as well as B-cell proliferation. Together, these results suggest that OX40 agonism has the potential to enhance antitumor immunity in human malignancies. Mol Cancer Ther; 17(5); 1024-38. ©2018 AACR . ©2018 American Association for Cancer Research.

Bone marrow stromal-B cell interactions in polycyclic aromatic hydrocarbon-induced pro/pre-B cell apoptosis.

PubMed

Allan, Lenka L; Mann, Koren K; Matulka, Raymond A; Ryu, Heui-Young; Schlezinger, Jennifer J; Sherr, David H

2003-12-01

Environmental polycyclic aromatic hydrocarbons (PAH) and related halogenated hydrocarbons are immunotoxic in a variety of systems. In a model system of B lymphopoiesis, PAH exposure rapidly induces apoptosis in CD43- pre-B and CD43+ pro/pre-B cells. Apoptosis induction by 7,12-dimethylbenzo[a]anthracene (DMBA) is dependent upon AhR+ bone marrow stromal cells and likely involves DMBA metabolism within the stromal cell. However, it is not known if PAH-treated stromal cells release free metabolites or soluble factors that may directly induce B cell death or if the effector death signal is delivered by stromal cell-B cell contact. Here, we demonstrate that supernatants from DMBA-treated bone marrow stromal cells contain an activity capable of inducing apoptosis in pro/pre-B cells cocultured with stromal cells. This activity (1) is not produced when stromal cells are cotreated with DMBA and alpha-naphthoflavone (alpha-NF), an aryl hydrocarbon receptor (AhR) and cytochrome P-450 inhibitor, (2) is > or = 50 kDa, (3) is trypsin and heat sensitive, and (4) is dependent on AhR+ stromal cells, which in turn deliver the effector death signal to pro/pre-B cells. The results (1) argue against a role for a soluble, stromal cell-derived cytokine as the effector of PAH-induced pro/pre-B cell death, (2) exclude the possibility of a free metabolite acting directly on AhR- pro/pre-B cell targets, and (3) suggest the elaboration by stromal cells of a relatively stable, DMBA metabolite-protein complex capable of acting on other stromal cells at some distance. Collectively, these studies suggest that, while stromal cell products, e.g., metabolite-protein complexes, may affect the function of distant stromal cells, the effector death signal delivered by stromal cells to bone marrow B cells is mediated by cell-cell contact.

Multiple layers of transcriptional regulation by PLZF in NKT-cell development.

PubMed

Mao, Ai-Ping; Constantinides, Michael G; Mathew, Rebecca; Zuo, Zhixiang; Chen, Xiaoting; Weirauch, Matthew T; Bendelac, Albert

2016-07-05

The transcription factor PLZF [promyelocytic leukemia zinc finger, encoded by zinc finger BTB domain containing 16 (Zbtb16)] is induced during the development of innate and innate-like lymphocytes to direct their acquisition of a T-helper effector program, but the molecular mechanisms involved are poorly understood. Using biotinylation-based ChIP-seq and microarray analysis of both natural killer T (NKT) cells and PLZF-transgenic thymocytes, we identified several layers of regulation of the innate-like NKT effector program. First, PLZF bound and regulated genes encoding cytokine receptors as well as homing and adhesion receptors; second, PLZF bound and activated T-helper-specific transcription factor genes that in turn control T-helper-specific programs; finally, PLZF bound and suppressed the transcription of Bach2, a potent general repressor of effector differentiation in naive T cells. These findings reveal the multilayered architecture of the transcriptional program recruited by PLZF and elucidate how a single transcription factor can drive the developmental acquisition of a broad effector program.

NFAT5-Regulated Macrophage Polarization Supports the Proinflammatory Function of Macrophages and T Lymphocytes.

PubMed

Tellechea, Mónica; Buxadé, Maria; Tejedor, Sonia; Aramburu, Jose; López-Rodríguez, Cristina

2018-01-01

Macrophages are exquisite sensors of tissue homeostasis that can rapidly switch between pro- and anti-inflammatory or regulatory modes to respond to perturbations in their microenvironment. This functional plasticity involves a precise orchestration of gene expression patterns whose transcriptional regulators have not been fully characterized. We had previously identified the transcription factor NFAT5 as an activator of TLR-induced responses, and in this study we explore its contribution to macrophage functions in different polarization settings. We found that both in classically and alternatively polarized macrophages, NFAT5 enhanced functions associated with a proinflammatory profile such as bactericidal capacity and the ability to promote Th1 polarization over Th2 responses. In this regard, NFAT5 upregulated the Th1-stimulatory cytokine IL-12 in classically activated macrophages, whereas in alternatively polarized ones it enhanced the expression of the pro-Th1 mediators Fizz-1 and arginase 1, indicating that it could promote proinflammatory readiness by regulating independent genes in differently polarized macrophages. Finally, adoptive transfer assays in vivo revealed a reduced antitumor capacity in NFAT5-deficient macrophages against syngeneic Lewis lung carcinoma and ID8 ovarian carcinoma cells, a defect that in the ID8 model was associated with a reduced accumulation of effector CD8 T cells at the tumor site. Altogether, detailed analysis of the effect of NFAT5 in pro- and anti-inflammatory macrophages uncovered its ability to regulate distinct genes under both polarization modes and revealed its predominant role in promoting proinflammatory macrophage functions. Copyright © 2017 by The American Association of Immunologists, Inc.

Interleukin-27 inhibits ectopic lymphoid-like structure development in early inflammatory arthritis

PubMed Central

Bombardieri, Michele; Greenhill, Claire J.; McLeod, Louise; Nerviani, Alessandra; Rocher-Ros, Vidalba; Cardus, Anna; Williams, Anwen S.; Pitzalis, Costantino; Jenkins, Brendan J.

2015-01-01

Ectopic lymphoid-like structures (ELSs) reminiscent of secondary lymphoid organs often develop at sites of chronic inflammation where they contribute to immune-mediated pathology. Through evaluation of synovial tissues from rheumatoid arthritis (RA) patients, we now show that low interleukin-27 (IL-27) expression corresponds with an increased incidence of ELS and gene signatures associated with their development and activity. The presence of synovial ELS was also noted in mice deficient in the IL-27 receptor (IL-27R) after the onset of inflammatory arthritis. Here, pathology was associated with increased synovial expression of pro-inflammatory cytokines, homeostatic chemokines, and transcriptional regulators linked with lymphoid neogenesis. In both clinical and experimental RA, synovial ELS coincided with the heightened local expression of cytokines and transcription factors of the Th17 and T follicular helper (Tfh) cell lineages, and included podoplanin-expressing T cells within lymphoid aggregates. IL-27 inhibited the differentiation of podoplanin-expressing Th17 cells, and an increased number of these cells were observed in IL-27R–deficient mice with inflammatory arthritis. Thus, IL-27 appears to negatively regulate ELS development in RA through control of effector T cells. These studies open new opportunities for patient stratification and treatment. PMID:26417004

Effector T Helper Cell Subsets in Inflammatory Bowel Diseases

PubMed Central

Imam, Tanbeena; Park, Sungtae; Kaplan, Mark H.; Olson, Matthew R.

2018-01-01

The gastrointestinal tract is a site of high immune challenge, as it must maintain a delicate balance between tolerating luminal contents and generating an immune response toward pathogens. CD4+ T cells are key in mediating the host protective and homeostatic responses. Yet, CD4+ T cells are also known to be the main drivers of inflammatory bowel disease (IBD) when this balance is perturbed. Many subsets of CD4+ T cells have been identified as players in perpetuating chronic intestinal inflammation. Over the last few decades, understanding of how each subset of Th cells plays a role has dramatically increased. Simultaneously, this has allowed development of therapeutic innovation targeting specific molecules rather than broad immunosuppressive agents. Here, we review the emerging evidence of how each subset functions in promoting and sustaining the chronic inflammation that characterizes IBD.

TLR4 ligands lipopolysaccharide and monophosphoryl lipid a differentially regulate effector and memory CD8+ T Cell differentiation.

PubMed

Cui, Weiguo; Joshi, Nikhil S; Liu, Ying; Meng, Hailong; Kleinstein, Steven H; Kaech, Susan M

2014-05-01

Vaccines formulated with nonreplicating pathogens require adjuvants to help bolster immunogenicity. The role of adjuvants in Ab production has been well studied, but how they influence memory CD8(+) T cell differentiation remains poorly defined. In this study we implemented dendritic cell-mediated immunization to study the effects of commonly used adjuvants, TLR ligands, on effector and memory CD8(+) T cell differentiation in mice. Intriguingly, we found that the TLR4 ligand LPS was far more superior to other TLR ligands in generating memory CD8(+) T cells upon immunization. LPS boosted clonal expansion similar to the other adjuvants, but fewer of the activated CD8(+) T cells died during contraction, generating a larger pool of memory cells. Surprisingly, monophosphoryl lipid A (MPLA), another TLR4 ligand, enhanced clonal expansion of effector CD8(+) T cells, but it also promoted their terminal differentiation and contraction; thus, fewer memory CD8(+) T cells formed, and MPLA-primed animals were less protected against secondary infection compared with those primed with LPS. Furthermore, gene expression profiling revealed that LPS-primed effector cells displayed a stronger pro-memory gene expression signature, whereas the gene expression profile of MPLA-primed effector cells aligned closer with terminal effector CD8(+) T cells. Lastly, we demonstrated that the LPS-TLR4-derived "pro-memory" signals were MyD88, but not Toll/IL-1R domain-containing adapter inducing IFN-β, dependent. This study reveals the influential power of adjuvants on the quantity and quality of CD8(+) T cell memory, and that attention to adjuvant selection is crucial because boosting effector cell expansion may not always equate with more memory T cells or greater protection.

TLR4 ligands LPS and MPLA differentially regulate effector and memory CD8+ T cell differentiation

PubMed Central

Cui, Weiguo; Joshi, Nikhil S.; Liu, Ying; Meng, Hailong; Kleinstein, Steven H; Kaech, Susan M.

2014-01-01

Vaccines formulated with non-replicating pathogens require adjuvants to help bolster immunogenicity. The role of adjuvants in antibody production has been well studied, but how they influence memory CD8+ T cell differentiation remains poorly defined. Here we implemented dendritic cell (DC)-mediated immunization to study the effects of commonly used adjuvants, TLR ligands, on effector and memory CD8+ T cell differentiation in mice. Intriguingly, we found that the TLR4 ligand LPS was far more superior to other TLR ligands in generating memory CD8+ T cells upon immunization. LPS boosted clonal expansion similar to the other adjuvants, but fewer of the activated CD8+ T cells died during contraction, generating a larger pool of memory cells. Surprisingly, monophosphoryl lipid A (MPLA), another TLR4 ligand, enhanced clonal expansion of effector CD8+ T cells, but also promoted their terminal differentiation and contraction; thus, fewer memory CD8+ T cells formed and MPLA-primed animals were less protected against secondary infection compared to those primed with LPS. Furthermore, gene expression profiling revealed that LPS-primed effector cells displayed a stronger pro-memory gene expression signature, whereas the gene expression profile of MPLA-primed effector cells aligned closer with terminal effector CD8+ T cells. Lastly, we demonstrated that the LPS-TLR4-derived “pro-memory” signals were MyD88, but not Trif, dependent. This study reveals the influential power of adjuvants on the quantity and quality of CD8+ T cell memory, and that attention to adjuvant selection is crucial because boosting effector cell expansion may not always equate with more memory T cells or greater protection. PMID:24659688

Stepwise cytoskeletal polarization as a series of checkpoints in innate but not adaptive cytolytic killing

NASA Astrophysics Data System (ADS)

Wülfing, Christoph; Purtic, Bozidar; Klem, Jennifer; Schatzle, John D.

2003-06-01

Cytolytic killing is a major effector mechanism in the elimination of virally infected and tumor cells. The innate cytolytic effectors, natural killer (NK) cells, and the adaptive effectors, cytotoxic T cells (CTL), despite differential immune recognition, both use the same lytic mechanism, cytolytic granule release. Using live cell video fluorescence microscopy in various primary cell models of NK cell and CTL killing, we show here that on tight target cell contact, a majority of the NK cells established cytoskeletal polarity required for effective lytic function slowly or incompletely. In contrast, CTLs established cytoskeletal polarity rapidly. In addition, NK cell killing was uniquely sensitive to minor interference with cytoskeletal dynamics. We propose that the stepwise NK cell cytoskeletal polarization constitutes a series of checkpoints in NK cell killing. In addition, the use of more deliberate progression to effector function to compensate for inferior immune recognition specificity provides a mechanistic explanation for how the same effector function can be used in the different functional contexts of the innate and adaptive immune response.

Space Station Crew Walks in Space to Conduct Robotics Upgrades

NASA Image and Video Library

2018-01-23

Outside the International Space Station, Expedition 54 Flight Engineers Mark Vande Hei and Scott Tingle of NASA conducted the first spacewalk this year Jan. 23 to replace a degraded latching end effector (LEE) on one end of the Canadarm2 robotic arm. There are two redundant end effectors on each end of the arm used to grapple visiting vehicles and components during a variety of operational activities. The spacewalk was the 206th in support of space station assembly and maintenance, the third in Vande Hei’s career and the first for Tingle. Vande Hei will venture outside the station again Jan. 29 with Flight Engineer Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) to stow a spare latching end effector removed from the robotic arm last October on to the station’s mobile base system rail car for future use.

Cellular Signaling Pathways and Posttranslational Modifications Mediated by Nematode Effector Proteins.

PubMed

Hewezi, Tarek

2015-10-01

Plant-parasitic cyst and root-knot nematodes synthesize and secrete a suite of effector proteins into infected host cells and tissues. These effectors are the major virulence determinants mediating the transformation of normal root cells into specialized feeding structures. Compelling evidence indicates that these effectors directly hijack or manipulate refined host physiological processes to promote the successful parasitism of host plants. Here, we provide an update on recent progress in elucidating the molecular functions of nematode effectors. In particular, we emphasize how nematode effectors modify plant cell wall structure, mimic the activity of host proteins, alter auxin signaling, and subvert defense signaling and immune responses. In addition, we discuss the emerging evidence suggesting that nematode effectors target and recruit various components of host posttranslational machinery in order to perturb the host signaling networks required for immunity and to regulate their own activity and subcellular localization. © 2015 American Society of Plant Biologists. All Rights Reserved.

Antigen-dependent proliferation and cytokine induction in respiratory syncytial virus-infected cotton rats reflect the presence of effector-memory T cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richter, Bettina W.M.; Onuska, Jaya M.; Niewiesk, Stefan

2005-06-20

Respiratory syncytial virus (RSV) is a major cause of lower airway disease in infants and children. Immunity to RSV is not long lasting, resulting in re-occurring infections throughout life. Effective long-lived immunity results when central-memory T cells that proliferate vigorously and secrete IL-2 are present. In contrast, effector-memory T cells that mainly produce IFN-{gamma}, facilitate virus clearance but are not long lived. To identify the type of memory response induced after RSV-A (Long) infection, we characterized the kinetics of the antigen-specific immune response and identified the types of cytokines induced. RSV-specific lymphocytic proliferation following primary and secondary infection was similar,more » and in both cases responses waned within a short period of time. In addition, mRNA for IFN-{gamma} but not IL-2 was induced in RSV-specific CD4{sup +} T cells. This supports the idea that the presence of effector-memory rather than central-memory T cells contributes to the ineffectiveness of the immune response to RSV.« less

Antibody-Dependent Cell-Mediated Cytotoxicity Effector-Enhanced EphA2 Agonist Monoclonal Antibody Demonstrates Potent Activity against Human Tumors1

PubMed Central

Bruckheimer, Elizabeth M; Fazenbaker, Christine A; Gallagher, Sandra; Mulgrew, Kathy; Fuhrmann, Stacy; Coffman, Karen T; Walsh, William; Ready, Shannon; Cook, Kim; Damschroder, Melissa; Kinch, Michael; Kiener, Peter A; Woods, Rob; Gao, Changshou; Dall'Acqua, William; Wu, Herren; Coats, Steven

2009-01-01

EphA2 is a receptor tyrosine kinase that has been shown to be overexpressed in a variety of human tumor types. Previous studies demonstrated that agonist monoclonal antibodies targeting EphA2 induced the internalization and degradation of the receptor, thereby abolishing its oncogenic effects. In this study, the in vitro and in vivo antibody-dependent cell-mediated cytotoxicity (ADCC) activity of EphA2 effector-enhanced agonist monoclonal antibodies was evaluated. With tumor cell lines and healthy human peripheral blood monocytes, the EphA2 antibodies demonstrated ∼80% tumor cell killing. In a dose-dependent manner, natural killer (NK) cells were required for the in vitro ADCC activity and became activated as demonstrated by the induction of cell surface expression of CD107a. To assess the role of NK cells on antitumor efficacy in vivo, the EphA2 antibodies were evaluated in xenograft models in severe compromised immunodeficient (SCID) mice (which have functional NK cells and monocytes) and SCID nonobese diabetic (NOD) mice (which largely lack functional NK cells and monocytes). Dosing of EphA2 antibody in the SCID murine tumor model resulted in a 6.2-fold reduction in tumor volume, whereas the SCID/nonobese diabetic model showed a 1.6-fold reduction over the isotype controls. Together, these results demonstrate that the anti-EphA2 monoclonal antibodies may function through at least two mechanisms of action: EphA2 receptor activation and ADCC-mediated activity. These novel EphA2 monoclonal antibodies provide additional means by which host effector mechanisms can be activated for selective destruction of EphA2-expressing tumor cells. PMID:19484140

Tight regulation of plant immune responses by combining promoter and suicide exon elements

DOE PAGES

Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.; ...

2015-07-02

Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightlymore » regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. In conclusion, beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes.« less

Tight regulation of plant immune responses by combining promoter and suicide exon elements

PubMed Central

Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.; Staskawicz, Brian J.; Loqué, Dominique; Hammond, Ming C.

2015-01-01

Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightly regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. Beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes. PMID:26138488

Tight regulation of plant immune responses by combining promoter and suicide exon elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonzalez, Tania L.; Liang, Yan; Nguyen, Bao N.

Effector-triggered immunity (ETI) is activated when plant disease resistance (R) proteins recognize the presence of pathogen effector proteins delivered into host cells. The ETI response generally encompasses a defensive ‘hypersensitive response’ (HR) that involves programmed cell death at the site of pathogen recognition. While many R protein and effector protein pairs are known to trigger HR, other components of the ETI signaling pathway remain elusive. Effector genes regulated by inducible promoters cause background HR due to leaky protein expression, preventing the generation of relevant transgenic plant lines. By employing the HyP5SM suicide exon, we have developed a strategy to tightlymore » regulate effector proteins such that HR is chemically inducible and non-leaky. This alternative splicing-based gene regulation system was shown to successfully control Bs2/AvrBs2-dependent and RPP1/ATR1Δ51-dependent HR in Nicotiana benthamiana and Nicotiana tabacum, respectively. It was also used to generate viable and healthy transgenic Arabidopsis thaliana plants that inducibly initiate HR. In conclusion, beyond enabling studies on the ETI pathway, our regulatory strategy is generally applicable to reduce or eliminate undesired background expression of transgenes.« less

Control of regulatory T cell lineage commitment and maintenance.

PubMed

Josefowicz, Steven Z; Rudensky, Alexander

2009-05-01

Foxp3-expressing regulatory T (Treg) cells suppress pathology mediated by immune responses against self and foreign antigens and commensal microorganisms. Sustained expression of the transcription factor Foxp3, a key distinguishing feature of Treg cells, is required for their differentiation and suppressor function. In addition, Foxp3 expression prevents deviation of Treg cells into effector T cell lineages and confers dependence of Treg cell survival and expansion on growth factors, foremost interleukin-2, provided by activated effector T cells. In this review we discuss Treg cell differentiation and maintenance with a particular emphasis on molecular regulation of Foxp3 expression, arguably a key to mechanistic understanding of biology of regulatory T cells.

Differential Expression of Alpha 4 Integrins on Effector Memory T Helper Cells during Bordetella Infections. Delayed Responses in Bordetella pertussis

PubMed Central

Ferguson, Ryan; Tarlton, Nicole; Wu, Victoria; Sequeira, Christopher S.; Bremer, Martina; Abramson, Tzvia

2012-01-01

Bordetella pertussis (B. pertussis) is the causative agent of whooping cough, a respiratory disease that is reemerging worldwide. Mechanisms of selective lymphocyte trafficking to the airways are likely to be critical in the immune response to this pathogen. We compared murine infection by B. pertussis, B. parapertussis, and a pertussis toxin-deleted B. pertussis mutant (BpΔPTX) to test the hypothesis that effector memory T-helper cells (emTh) display an altered pattern of trafficking receptor expression in B. pertussis infection due to a defect in imprinting. Increased cell recruitment to the lungs at 5 days post infection (p.i.) with B. parapertussis, and to a lesser extent with BpΔPTX, coincided with an increased frequency of circulating emTh cells expressing the mucosal-associated trafficking receptors α4β7 and α4β1 while a reduced population of these cells was observed in B. pertussis infection. These cells were highly evident in the blood and lungs in B. pertussis infection only at 25 days p.i. when B. parapertussis and BpΔPTX infections were resolved. Although at 5 days p.i., an equally high percentage of lung dendritic cells (DCs) from all infections expressed maturation markers, this expression persisted only in B. pertussis infection at 25 days p.i. Furthermore, at 5 days p.i with B. pertussis, lung DCs migration to draining lymph nodes may be compromised as evidenced by decreased frequency of CCR7+ DCs, inhibited CCR7-mediated in vitro migration, and fewer DCs in lung draining lymph nodes. Lastly, a reduced frequency of allogeneic CD4+ cells expressing α4β1 was detected following co-culture with lung DCs from B. pertussis-infected mice, suggesting a defect in DC imprinting in comparison to the other infection groups. The findings in this study suggest that B. pertussis may interfere with imprinting of lung-associated trafficking receptors on T lymphocytes leading to extended survival in the host and a prolonged course of disease. PMID:23300813

Functional differences between PD-1+ and PD-1- CD4+ effector T cells in healthy donors and patients with glioblastoma multiforme

PubMed Central

Lucca, Liliana E.; Lerner, Benjamin A.; Gunel, Murat; Raddassi, Khadir; Coric, Vlad; Hafler, David A.; Love, J. Christopher

2017-01-01

Immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) have been highly successful in the treatment of cancer. While PD-1 expression has been widely investigated, its role in CD4+ effector T cells in the setting of health and cancer remains unclear, particularly in the setting of glioblastoma multiforme (GBM), the most aggressive and common form of brain cancer. We examined the functional and molecular features of PD-1+CD4+CD25—CD127+Foxp3—effector cells in healthy subjects and in patients with GBM. In healthy subjects, we found that PD-1+CD4+ effector cells are dysfunctional: they do not proliferate but can secrete large quantities of IFNγ. Strikingly, blocking antibodies against PD-1 did not rescue proliferation. RNA-sequencing revealed features of exhaustion in PD-1+ CD4 effectors. In the context of GBM, tumors were enriched in PD-1+ CD4+ effectors that were similarly dysfunctional and unable to proliferate. Furthermore, we found enrichment of PD-1+TIM-3+ CD4+ effectors in tumors, suggesting that co-blockade of PD-1 and TIM-3 in GBM may be therapeutically beneficial. RNA-sequencing of blood and tumors from GBM patients revealed distinct differences between CD4+ effectors from both compartments with enrichment in multiple gene sets from tumor infiltrating PD-1—CD4+ effectors cells. Enrichment of these gene sets in tumor suggests a more metabolically active cell state with signaling through other co-receptors. PD-1 expression on CD4 cells identifies a dysfunctional subset refractory to rescue with PD-1 blocking antibodies, suggesting that the influence of immune checkpoint inhibitors may involve recovery of function in the PD-1—CD4+ T cell compartment. Additionally, co-blockade of PD-1 and TIM-3 in GBM may be therapeutically beneficial. PMID:28880903

Expression pattern and phosphorylation status of Smad2/3 in different subtypes of human first trimester trophoblast.

PubMed

Haider, S; Kunihs, V; Fiala, C; Pollheimer, J; Knöfler, M

2017-09-01

TGF-β superfamily members are thought to play a pivotal role in placental development and differentiation. However, their downstream effectors, the Smad transcription factors, have been poorly investigated in human trophoblasts. Expression and localisation of the canonical TGF-β targets Smad2/3 and their regulators (Smad4 and Smad7) were investigated in first trimester placenta and purified cytotrophoblast (CTB) subtypes using immunofluorescence, western blotting and qPCR. Canonical and non-canonical activation was analysed in nuclear/cytoplasmic extracts of trophoblast subtypes as well as in tissue sections using antibodies against Smad2/3, phosphorylated either at the C-terminus (pSmad2C/3C) or in their linker regions (pSmad2L/3L). Smad phosphorylation was also examined in differentiating extravillous trophoblasts (EVTs) in the absence or presence of decidual stromal cell (DSC)-conditioned medium. Smad2, Smad4 and Smad7 protein were uniformly expressed between 6th and 12th week placentae and the different isolated CTB subtypes. Activated pSmad2L was mainly detected in nuclei and cytoplasm of villous CTBs, whereas pSmad2C was absent from these cells. In contrast, pSmad2C could be detected in the cytoplasm of cell column trophoblasts and in the cytoplasm/nuclei of EVTs. Smad3 and its phosphorylated forms pSmad3C and pSmad3L specifically localised to EVT nuclei. During EVT differentiation autocrine activation of pSmad2C/3C and pSmad3L was observed. DSC-conditioned medium further increased Smad2/3 phosphorylation in EVTs. The lack of pSmad2C in villous CTBs suggests that other mitogens than TGF-β could promote Smad2 linker phosphorylation under homeostatic conditions. Whereas autocrine signalling activates Smad2/3 in differentiating EVTs, paracrine factors contribute to Smad phosphorylation in these cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ralstonia solanacearum Type III Effector RipAY Is a Glutathione-Degrading Enzyme That Is Activated by Plant Cytosolic Thioredoxins and Suppresses Plant Immunity.

PubMed

Mukaihara, Takafumi; Hatanaka, Tadashi; Nakano, Masahito; Oda, Kenji

2016-04-12

The plant pathogen Ralstonia solanacearum uses a large repertoire of type III effector proteins to succeed in infection. To clarify the function of effector proteins in host eukaryote cells, we expressed effectors in yeast cells and identified seven effector proteins that interfere with yeast growth. One of the effector proteins, RipAY, was found to share homology with the ChaC family proteins that function as γ-glutamyl cyclotransferases, which degrade glutathione (GSH), a tripeptide that plays important roles in the plant immune system. RipAY significantly inhibited yeast growth and simultaneously induced rapid GSH depletion when expressed in yeast cells. The in vitro GSH degradation activity of RipAY is specifically activated by eukaryotic factors in the yeast and plant extracts. Biochemical purification of the yeast protein identified that RipAY is activated by thioredoxin TRX2. On the other hand, RipAY was not activated by bacterial thioredoxins. Interestingly, RipAY was activated by plant h-type thioredoxins that exist in large amounts in the plant cytosol, but not by chloroplastic m-, f-, x-, y- and z-type thioredoxins, in a thiol-independent manner. The transient expression of RipAY decreased the GSH level in plant cells and affected the flg22-triggered production of reactive oxygen species (ROS) and expression of pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker genes in Nicotiana benthamiana leaves. These results indicate that RipAY is activated by host cytosolic thioredoxins and degrades GSH specifically in plant cells to suppress plant immunity. Ralstonia solanacearum is the causal agent of bacterial wilt disease of plants. This pathogen injects virulence effector proteins into host cells to suppress disease resistance responses of plants. In this article, we report a biochemical activity of R. solanacearum effector protein RipAY. RipAY can degrade GSH, a tripeptide that plays important roles in the plant immune system, with its γ-glutamyl cyclotransferase activity. The high GSH degradation activity of RipAY is considered to be a good weapon for this bacterium to suppress plant immunity. However, GSH also plays important roles in bacterial tolerance to various stresses and growth. Interestingly, RipAY has an excellent safety mechanism to prevent unwanted firing of its enzyme activity in bacterial cells because RipAY is specifically activated by host eukaryotic thioredoxins. This study also reveals a novel host plant protein acting as a molecular switch for effector activation. Copyright © 2016 Mukaihara et al.

Identification of novel Xanthomonas euvesicatoria type III effector proteins by a machine-learning approach.

PubMed

Teper, Doron; Burstein, David; Salomon, Dor; Gershovitz, Michael; Pupko, Tal; Sessa, Guido

2016-04-01

The Gram-negative bacterium Xanthomonas euvesicatoria (Xcv) is the causal agent of bacterial spot disease in pepper and tomato. Xcv pathogenicity depends on a type III secretion (T3S) system that delivers effector proteins into host cells to suppress plant immunity and promote disease. The pool of known Xcv effectors includes approximately 30 proteins, most identified in the 85-10 strain by various experimental and computational techniques. To identify additional Xcv 85-10 effectors, we applied a genome-wide machine-learning approach, in which all open reading frames (ORFs) were scored according to their propensity to encode effectors. Scoring was based on a large set of features, including genomic organization, taxonomic dispersion, hypersensitive response and pathogenicity (hrp)-dependent expression, 5' regulatory sequences, amino acid composition bias and GC content. Thirty-six predicted effectors were tested for translocation into plant cells using the hypersensitive response (HR)-inducing domain of AvrBs2 as a reporter. Seven proteins (XopAU, XopAV, XopAW, XopAP, XopAX, XopAK and XopAD) harboured a functional translocation signal and their translocation relied on the HrpF translocon, indicating that they are bona fide T3S effectors. Remarkably, four belong to novel effector families. Inactivation of the xopAP gene reduced the severity of disease symptoms in infected plants. A decrease in cell death and chlorophyll content was observed in pepper leaves inoculated with the xopAP mutant when compared with the wild-type strain. However, populations of the xopAP mutant in infected leaves were similar in size to those of wild-type bacteria, suggesting that the reduction in virulence was not caused by impaired bacterial growth. © 2015 BSPP and John Wiley & Sons Ltd.

CD4+VEGFR1(HIGH) T cell as a novel Treg subset regulates inflammatory bowel disease in lymphopenic mice.

PubMed

Shin, Jin-Young; Yoon, Il-Hee; Lim, Jong-Hyung; Shin, Jun-Seop; Nam, Hye-Young; Kim, Yong-Hee; Cho, Hyoung-Soo; Hong, So-Hee; Kim, Jung-Sik; Lee, Won-Woo; Park, Chung-Gyu

2015-09-01

Regulatory T cells (Tregs) are a specialized subpopulation of T cells that control the immune response and thereby maintain immune system homeostasis and tolerance to self-antigens. Many subsets of CD4(+) Tregs have been identified, including Foxp3(+), Tr1, Th3, and Foxp3neg iT(R)35 cells. In this study, we identified a new subset of CD4(+)VEGFR1(high) Tregs that have immunosuppressive capacity. CD4(+)VEGFR1high T cells, which constitute approximately 1.0% of CD4(+) T cells, are hyporesponsive to T-cell antigen receptor stimulation. Surface marker and FoxP3 expression analysis revealed that CD4(+)VEGFR1(high) T cells are distinct from known Tregs. CD4(+)VEGFR1(high) T cells suppressed the proliferation of CD4(+)CD25(-) T cell as efficiently as CD4(+)CD25(high) natural Tregs in a contact-independent manner. Furthermore, adoptive transfer of CD4(+)VEGFR1(+) T cells from wild type to RAG-2-deficient C57BL/6 mice inhibited effector T-cell-mediated inflammatory bowel disease. Thus, we report CD4(+) VEGFR1(high) T cells as a novel subset of Tregs that regulate the inflammatory response in the intestinal tract.

Intranasal immunization with protective antigen of Bacillus anthracis induces a long-term immunological memory response.

PubMed

Woo, Sun-Je; Kang, Seok-Seong; Park, Sung-Moo; Yang, Jae Seung; Song, Man Ki; Yun, Cheol-Heui; Han, Seung Hyun

2015-10-01

Although intranasal vaccination has been shown to be effective for the protection against inhalational anthrax, establishment of long-term immunity has yet to be achieved. Here, we investigated whether intranasal immunization with recombinant protective antigen (rPA) of Bacillus anthracis induces immunological memory responses in the mucosal and systemic compartments. Intranasal immunization with rPA plus cholera toxin (CT) sustained PA-specific antibody responses for 6 months in lung, nasal washes, and vaginal washes as well as serum. A significant induction of PA-specific memory B cells was observed in spleen, cervical lymph nodes (CLNs) and lung after booster immunization. Furthermore, intranasal immunization with rPA plus CT remarkably generated effector memory CD4(+) T cells in the lung. PA-specific CD4(+) T cells preferentially increased the expression of Th1- and Th17-type cytokines in lung, but not in spleen or CLNs. Collectively, the intranasal immunization with rPA plus CT promoted immunologic memory responses in the mucosal and systemic compartments, providing long-term immunity. Copyright © 2015 Elsevier Ltd. All rights reserved.

Genomic characterisation of the effector complement of the potato cyst nematode Globodera pallida.

PubMed

Thorpe, Peter; Mantelin, Sophie; Cock, Peter Ja; Blok, Vivian C; Coke, Mirela C; Eves-van den Akker, Sebastian; Guzeeva, Elena; Lilley, Catherine J; Smant, Geert; Reid, Adam J; Wright, Kathryn M; Urwin, Peter E; Jones, John T

2014-10-23

The potato cyst nematode Globodera pallida has biotrophic interactions with its host. The nematode induces a feeding structure - the syncytium - which it keeps alive for the duration of the life cycle and on which it depends for all nutrients required to develop to the adult stage. Interactions of G. pallida with the host are mediated by effectors, which are produced in two sets of gland cells. These effectors suppress host defences, facilitate migration and induce the formation of the syncytium. The recent completion of the G. pallida genome sequence has allowed us to identify the effector complement from this species. We identify 128 orthologues of effectors from other nematodes as well as 117 novel effector candidates. We have used in situ hybridisation to confirm gland cell expression of a subset of these effectors, demonstrating the validity of our effector identification approach. We have examined the expression profiles of all effector candidates using RNAseq; this analysis shows that the majority of effectors fall into one of three clusters of sequences showing conserved expression characteristics (invasive stage nematode only, parasitic stage only or invasive stage and adult male only). We demonstrate that further diversity in the effector pool is generated by alternative splicing. In addition, we show that effectors target a diverse range of structures in plant cells, including the peroxisome. This is the first identification of effectors from any plant pathogen that target this structure. This is the first genome scale search for effectors, combined to a life-cycle expression analysis, for any plant-parasitic nematode. We show that, like other phylogenetically unrelated plant pathogens, plant parasitic nematodes deploy hundreds of effectors in order to parasitise plants, with different effectors required for different phases of the infection process.

Evidence of the immunomodulatory role of dual PI3K/mTOR inhibitors in transplantation: an experimental study in mice.

PubMed

Vilchez, Valery; Turcios, Lilia; Butterfield, David A; Mitov, Mihail I; Coquillard, Cristin L; Brandon, Ja Anthony; Cornea, Virgilius; Gedaly, Roberto; Marti, Francesc

2017-10-01

The PI3K/mTOR signaling cascade is fundamental in T-cell activation and fate decisions. We showed the distinct regulation of PI3K/mTOR in regulatory and effector T-cells and proposed the potential therapeutic benefit of targeting this pathway to control the balance between effector and regulatory T-cell activities. Substantial adverse effects in long-term clinical usage of rapamycin suggest the use of alternative treatments in restraining effector T-cell function in transplant patients. We hypothesize that dual PI3K/mTOR inhibitors may represent an immunosuppressant alternative. Here we show that dual PI3K/mTOR PI-103 and PKI-587 inhibitors interfered IL-2-dependent responses in T-cells. However, in contrast to the inhibitory effects in non-Treg T-cell proliferation and effector functions, dual inhibitors increased the differentiation, preferential expansion, and suppressor activity of iTregs. Rapamycin, PI-103, and PKI-587 targeted different signaling events and induced different metabolic patterns in primary T-cells. Similar to rapamycin, in vivo administration of PI-103 and PKI-587 controlled effectively the immunological response against allogeneic skin graft. These results characterize specific regulatory mechanisms of dual PI3K/mTOR inhibitors in T-cells and support their potential as a novel therapeutic option in transplantation. © 2017 Steunstichting ESOT.

A translocator-specific export signal establishes the translocator-effector secretion hierarchy that is important for type III secretion system function

PubMed Central

Tomalka, Amanda G.; Stopford, Charles M.; Lee, Pei-Chung; Rietsch, Arne

2012-01-01

Summary Type III secretion systems are used by many Gram-negative pathogens to directly deliver effector proteins into the cytoplasm of host cells. To accomplish this, bacteria secrete translocator proteins that form a pore in the host-cell membrane through which the effector proteins are then introduced into the host cell. Evidence from multiple systems indicates that the pore-forming translocator proteins are exported before effectors, but how this secretion hierarchy is established is unclear. Here we used the P. aeruginosa translocator protein PopD as a model to identify its export signals. The amino-terminal secretion signal and chaperone, PcrH, are required for export under all conditions. Two novel signals in PopD, one proximal to the chaperone-binding site and one at the very C-terminus of the protein, are required for export of PopD before effector proteins. These novel export signals establish the translocator-effector secretion hierarchy, which in turn, is critical for the delivery of effectors into host cells. PMID:23121689

Effectors of root sedentary nematodes target diverse plant cell compartments to manipulate plant functions and promote infection.

PubMed

Jaouannet, Maëlle; Rosso, Marie-Noëlle

2013-09-01

Sedentary plant-parasitic nematodes maintain a biotrophic relationship with their hosts over a period of several weeks and induce the differentiation of root cells into specialized feeding cells. Nematode effectors, which are synthesized in the esophageal glands and injected into the plant tissue through the syringe-like stylet, play a central role in these processes. Previous work on nematode effectors has shown that the apoplasm is targeted during invasion of the host while the cytoplasm is targeted during the induction and the maintenance of the feeding site. A large number of candidate effectors potentially secreted by the nematode into the plant tissues to promote infection have now been identified. This work has shown that the targeting and the role of effectors are more complex than previously thought. This review will not cover the prolific recent findings in nematode effector function but will instead focus on recent selected examples that illustrate the variety of plant cell compartments that effectors are addressed to in order reach their plant targets.

In Planta Processing and Glycosylation of a Nematode CLAVATA3/ENDOSPERM SURROUNDING REGION-Like Effector and Its Interaction with a Host CLAVATA2-Like Receptor to Promote Parasitism1[OPEN

PubMed Central

Chen, Shiyan; Lang, Ping; Chronis, Demosthenis; Zhang, Sheng; De Jong, Walter S.; Mitchum, Melissa G.

2015-01-01

Like other biotrophic plant pathogens, plant-parasitic nematodes secrete effector proteins into host cells to facilitate infection. Effector proteins that mimic plant CLAVATA3/ENDOSPERM SURROUNDING REGION-related (CLE) proteins have been identified in several cyst nematodes, including the potato cyst nematode (PCN); however, the mechanistic details of this cross-kingdom mimicry are poorly understood. Plant CLEs are posttranslationally modified and proteolytically processed to function as bioactive ligands critical to various aspects of plant development. Using ectopic expression coupled with nanoliquid chromatography-tandem mass spectrometry analysis, we show that the in planta mature form of proGrCLE1, a multidomain CLE effector secreted by PCN during infection, is a 12-amino acid arabinosylated glycopeptide (named GrCLE1-1Hyp4,7g) with striking structural similarity to mature plant CLE peptides. This glycopeptide is more resistant to hydrolytic degradation and binds with higher affinity to a CLAVATA2-like receptor (StCLV2) from potato (Solanum tuberosum) than its nonglycosylated forms. We further show that StCLV2 is highly up-regulated at nematode infection sites and that transgenic potatoes with reduced StCLV2 expression are less susceptible to PCN infection, indicating that interference of the CLV2-mediated signaling pathway confers nematode resistance in crop plants. These results strongly suggest that phytonematodes have evolved to utilize host cellular posttranslational modification and processing machinery for the activation of CLE effectors following secretion into plant cells and highlight the significance of arabinosylation in regulating nematode CLE effector activity. Our finding also provides evidence that multidomain CLEs are modified and processed similarly to single-domain CLEs, adding new insight into CLE maturation in plants. PMID:25416475

Altered levels of memory T cell subsets and common γc cytokines in Strongyloides stercoralis infection and partial reversal following anthelmintic treatment.

PubMed

Rajamanickam, Anuradha; Munisankar, Saravanan; Bhootra, Yukti; Dolla, Chandra Kumar; Thiruvengadam, Kannan; Nutman, Thomas B; Babu, Subash

2018-05-01

CD4+ and CD8+ T cells are central players in immunity to helminth infections. However, the role of T cell subsets in human helminth infections is not well understood. In addition, the common γc cytokines, IL-2, IL-4, IL-7, IL-9 and IL-15 play an important role in the maintenance of these CD4+ and CD8+ T cell subsets. To examine the major T cell subsets and their association with the common γc cytokines, the absolute numbers of CD4+ and CD8+ naïve, central memory, effector memory and effector cells and the plasma levels of IL-2, IL-4, IL-7, IL-9 and IL-15 were measured in Strongyloides stercoralis (Ss) infected (INF, n = 60), helminth-uninfected (UN, n = 58) and in post treatment INF individuals. Ss infection is characterized by significantly increased absolute numbers of naïve and decreased absolute numbers of central and effector memory CD4+ T cells in comparison to UN individuals. No significant difference in the numbers of CD8+ T cell subsets was observed between the groups. The numbers of naïve cells and central memory CD4+ T cells were significantly reversed after anthelmintic treatment. Circulating levels of IL-2, IL-7 and IL-15 were significantly diminished, whereas the levels of IL-4 and IL-9 were significantly increased in INF compared to UN individuals. Following anthelminthic treatment, IL-2, IL-7 and IL-15 levels were significantly increased, while IL-4 and IL-9 levels were significantly decreased. Our data also showed a significant positive correlation between the levels of IL-7 and the numbers of central and effector memory CD4+ T cells. Ss infection is characterized by alterations in the absolute numbers of CD4+ T cell subsets and altered levels of common γc cytokines IL-2, IL-4, IL-7, IL-9 and IL-15; alterations which are partially reversed after anthelmintic treatment.

Delivery of cytoplasmic and apoplastic effectors from Phytophthora infestans haustoria by distinct secretion pathways.

PubMed

Wang, Shumei; Boevink, Petra C; Welsh, Lydia; Zhang, Ruofang; Whisson, Stephen C; Birch, Paul R J

2017-10-01

The potato blight pathogen Phytophthora infestans secretes effector proteins that are delivered inside (cytoplasmic) or can act outside (apoplastic) plant cells to neutralize host immunity. Little is known about how and where effectors are secreted during infection, yet such knowledge is essential to understand and combat crop disease. We used transient Agrobacterium tumefaciens-mediated in planta expression, transformation of P. infestans with fluorescent protein fusions and confocal microscopy to investigate delivery of effectors to plant cells during infection. The cytoplasmic effector Pi04314, expressed as a monomeric red fluorescent protein (mRFP) fusion protein with a signal peptide to secrete it from plant cells, did not passively re-enter the cells upon secretion. However, Pi04314-mRFP expressed in P. infestans was translocated from haustoria, which form intimate interactions with plant cells, to accumulate at its sites of action in the host nucleus. The well-characterized apoplastic effector EPIC1, a cysteine protease inhibitor, was also secreted from haustoria. EPIC1 secretion was inhibited by brefeldin A (BFA), demonstrating that it is delivered by conventional Golgi-mediated secretion. By contrast, Pi04314 secretion was insensitive to BFA treatment, indicating that the cytoplasmic effector follows an alternative route for delivery into plant cells. Phytophthora infestans haustoria are thus sites for delivery of both apoplastic and cytoplasmic effectors during infection, following distinct secretion pathways. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

A translocated effector required for Bartonella dissemination from derma to blood safeguards migratory host cells from damage by co-translocated effectors.

PubMed

Okujava, Rusudan; Guye, Patrick; Lu, Yun-Yueh; Mistl, Claudia; Polus, Florine; Vayssier-Taussat, Muriel; Halin, Cornelia; Rolink, Antonius G; Dehio, Christoph

2014-06-01

Numerous bacterial pathogens secrete multiple effectors to modulate host cellular functions. These effectors may interfere with each other to efficiently control the infection process. Bartonellae are Gram-negative, facultative intracellular bacteria using a VirB type IV secretion system to translocate a cocktail of Bartonella effector proteins (Beps) into host cells. Based on in vitro infection models we demonstrate here that BepE protects infected migratory cells from injurious effects triggered by BepC and is required for in vivo dissemination of bacteria from the dermal site of inoculation to blood. Human endothelial cells (HUVECs) infected with a ΔbepE mutant of B. henselae (Bhe) displayed a cell fragmentation phenotype resulting from Bep-dependent disturbance of rear edge detachment during migration. A ΔbepCE mutant did not show cell fragmentation, indicating that BepC is critical for triggering this deleterious phenotype. Complementation of ΔbepE with BepEBhe or its homologues from other Bartonella species abolished cell fragmentation. This cyto-protective activity is confined to the C-terminal Bartonella intracellular delivery (BID) domain of BepEBhe (BID2.EBhe). Ectopic expression of BID2.EBhe impeded the disruption of actin stress fibers by Rho Inhibitor 1, indicating that BepE restores normal cell migration via the RhoA signaling pathway, a major regulator of rear edge retraction. An intradermal (i.d.) model for B. tribocorum (Btr) infection in the rat reservoir host mimicking the natural route of infection by blood sucking arthropods allowed demonstrating a vital role for BepE in bacterial dissemination from derma to blood. While the Btr mutant ΔbepDE was abacteremic following i.d. inoculation, complementation with BepEBtr, BepEBhe or BIDs.EBhe restored bacteremia. Given that we observed a similar protective effect of BepEBhe on infected bone marrow-derived dendritic cells migrating through a monolayer of lymphatic endothelial cells we propose that infected dermal dendritic cells may be involved in disseminating Bartonella towards the blood stream in a BepE-dependent manner.

A Translocated Effector Required for Bartonella Dissemination from Derma to Blood Safeguards Migratory Host Cells from Damage by Co-translocated Effectors

PubMed Central

Okujava, Rusudan; Guye, Patrick; Lu, Yun-Yueh; Mistl, Claudia; Polus, Florine; Vayssier-Taussat, Muriel; Halin, Cornelia; Rolink, Antonius G.; Dehio, Christoph

2014-01-01

Numerous bacterial pathogens secrete multiple effectors to modulate host cellular functions. These effectors may interfere with each other to efficiently control the infection process. Bartonellae are Gram-negative, facultative intracellular bacteria using a VirB type IV secretion system to translocate a cocktail of Bartonella effector proteins (Beps) into host cells. Based on in vitro infection models we demonstrate here that BepE protects infected migratory cells from injurious effects triggered by BepC and is required for in vivo dissemination of bacteria from the dermal site of inoculation to blood. Human endothelial cells (HUVECs) infected with a ΔbepE mutant of B. henselae (Bhe) displayed a cell fragmentation phenotype resulting from Bep-dependent disturbance of rear edge detachment during migration. A ΔbepCE mutant did not show cell fragmentation, indicating that BepC is critical for triggering this deleterious phenotype. Complementation of ΔbepE with BepEBhe or its homologues from other Bartonella species abolished cell fragmentation. This cyto-protective activity is confined to the C-terminal Bartonella intracellular delivery (BID) domain of BepEBhe (BID2.EBhe). Ectopic expression of BID2.EBhe impeded the disruption of actin stress fibers by Rho Inhibitor 1, indicating that BepE restores normal cell migration via the RhoA signaling pathway, a major regulator of rear edge retraction. An intradermal (i.d.) model for B. tribocorum (Btr) infection in the rat reservoir host mimicking the natural route of infection by blood sucking arthropods allowed demonstrating a vital role for BepE in bacterial dissemination from derma to blood. While the Btr mutant ΔbepDE was abacteremic following i.d. inoculation, complementation with BepEBtr, BepEBhe or BIDs.EBhe restored bacteremia. Given that we observed a similar protective effect of BepEBhe on infected bone marrow-derived dendritic cells migrating through a monolayer of lymphatic endothelial cells we propose that infected dermal dendritic cells may be involved in disseminating Bartonella towards the blood stream in a BepE-dependent manner. PMID:24945914

In vitro priming of adoptively transferred T cells with a RORγ agonist confers durable memory and stemness in vivo.

PubMed

Hu, Xiao; Majchrzak, Kinga; Liu, Xikui; Wyatt, Megan M; Spooner, Chauncey; Moisan, Jacques; Zou, Weiping; Carter, Laura L; Paulos, Chrystal M

2018-05-16

Adoptive T cell transfer therapy is an FDA-approved treatment for leukemia that relies on the ex vivo expansion and re-infusion of a patient's immune cells, which can be engineered with a chimeric antigen receptor (CAR) for more efficient tumor recognition. Type 17 T cells, controlled transcriptionally by RORγ, have been reported to mediate potent anti-tumor effects superior to those observed with conventionally expanded T cells. Here we demonstrate that addition of a synthetic, small molecule RORγ agonist during ex vivo expansion potentiates the anti-tumor activity of human Th17 and Tc17 cells redirected with a CAR. Likewise, ex vivo use of this agonist bolstered the anti-tumor properties of murine tumor-specific CD4+ and CD8+ T cells. Expansion in the presence of the RORγ agonist enhanced IL-17A production without compromising IFN-γ secretion in vitro. In vivo, cytokine neutralization studies revealed that IFN-γ and IL-17A were required to regress murine melanoma tumors. The enhanced anti-tumor effect of RORγ agonist treatment was associated with recovery of more donor T cells in the tumor and spleen; these cells produced elevated levels of cytokines months after infusion and expressed markers of long-lived stem and central memory cells such as Tcf7 and CD62L. Conversely, untreated cells mainly exhibited effector phenotypes in the tumor. Cured mice previously treated with agonist-primed T cells were protected from tumor re-challenge. Collectively, our work reveals that in vitro treatment with a RORγ agonist generates potent anti-tumor Type 17 effector cells that persist as long-lived memory cells in vivo. Copyright ©2018, American Association for Cancer Research.

Collagen-induced arthritis in Dark Agouti rats as a model for study of immunological sexual dimorphisms in the human disease.

PubMed

Dimitrijević, Mirjana; Arsenović-Ranin, Nevena; Bufan, Biljana; Nacka-Aleksić, Mirjana; Macanović, Mirjana Lazarević; Milovanović, Petar; Đurić, Marija; Sopta, Jelena; Leposavić, Gordana

2018-05-21

Collagen-induced arthritis (CIA) is a frequently used animal model of rheumatoid arthritis, human autoimmune disease that exhibits clear sex bias in incidence and clinical course. Female Dark Agouti rats immunized for CIA showed also greater incidence and higher arthritic score than their male counterparts. The study investigated sex differences in mechanisms controlling the primary immune responses in draining lymph nodes (dLNs), as a factor contributing to this dimorphism. The higher frequencies of CD4 + CD25 + Foxp3- cells, presumably activated effector T (Teff) cells, and IL-17+, IFN-γ + and IL-17 + IFN-γ + T cells were found in female compared with male rat dLNs. However, the frequency of CD4 + CD25 + Foxp3+ T regulatory cells (Treg) did not differ between sexes. Thus, CD4+ Teff cells/Treg ratio, and IL-17+ T cells/Treg and IFN-γ + T cells/Treg ratios were higher in female than in male rats, and among them was found lower frequency of PD-1+ cells. This suggested less efficient control of (auto)immune Th1/Th17 cell responses in female rat dLNs. On the contrary, the frequency of IL-4+ T cells was lower in female than in male rat dLNs. Consistently, the ratio of serum levels of collagen-specific IgG2a (IFN-γ-dependent, with an important pathogenic role in CIA) and IgG1 (IL-4-dependent) was shifted towards IgG2a in female compared with male rats. As a whole, the study suggests that sexual dimorphism in the control of T cell activation/polarization could contribute to sex bias in the susceptibility to CIA. Moreover, the study advises the use of animals of both sexes in the preclinical testing of new drugs for rheumatoid arthritis. Copyright © 2018 Elsevier Inc. All rights reserved.

A Plethora of Virulence Strategies Hidden Behind Nuclear Targeting of Microbial Effectors

PubMed Central

Rivas, Susana; Genin, Stéphane

2011-01-01

Plant immune responses depend on the ability to couple rapid recognition of the invading microbe to an efficient response. During evolution, plant pathogens have acquired the ability to deliver effector molecules inside host cells in order to manipulate cellular and molecular processes and establish pathogenicity. Following translocation into plant cells, microbial effectors may be addressed to different subcellular compartments. Intriguingly, a significant number of effector proteins from different pathogenic microorganisms, including viruses, oomycetes, fungi, nematodes, and bacteria, is targeted to the nucleus of host cells. In agreement with this observation, increasing evidence highlights the crucial role played by nuclear dynamics, and nucleocytoplasmic protein trafficking during a great variety of analyzed plant–pathogen interactions. Once in the nucleus, effector proteins are able to manipulate host transcription or directly subvert essential host components to promote virulence. Along these lines, it has been suggested that some effectors may affect histone packing and, thereby, chromatin configuration. In addition, microbial effectors may either directly activate transcription or target host transcription factors to alter their regular molecular functions. Alternatively, nuclear translocation of effectors may affect subcellular localization of their cognate resistance proteins in a process that is essential for resistance protein-mediated plant immunity. Here, we review recent progress in our field on the identification of microbial effectors that are targeted to the nucleus of host plant cells. In addition, we discuss different virulence strategies deployed by microbes, which have been uncovered through examination of the mechanisms that guide nuclear localization of effector proteins. PMID:22639625

The Rab27a effector exophilin7 promotes fusion of secretory granules that have not been docked to the plasma membrane.

PubMed

Wang, Hao; Ishizaki, Ray; Xu, Jun; Kasai, Kazuo; Kobayashi, Eri; Gomi, Hiroshi; Izumi, Tetsuro

2013-02-01

Granuphilin, an effector of the small GTPase Rab27a, mediates the stable attachment (docking) of insulin granules to the plasma membrane and inhibits subsequent fusion of docked granules, possibly through interaction with a fusion-inhibitory Munc18-1/syntaxin complex. However, phenotypes of insulin exocytosis differ considerably between Rab27a- and granuphilin-deficient pancreatic β cells, suggesting that other Rab27a effectors function in those cells. We found that one of the putative Rab27a effector family proteins, exophilin7/JFC1/Slp1, is expressed in β cells; however, unlike granuphilin, exophilin7 overexpressed in the β-cell line MIN6 failed to show granule-docking or fusion-inhibitory activity. Furthermore, exophilin7 has no affinities to either Munc18-1 or Munc18-1-interacting syntaxin-1a, in contrast to granuphilin. Although β cells of exophilin7-knockout mice show no apparent abnormalities in intracellular distribution or in ordinary glucose-induced exocytosis of insulin granules, they do show impaired fusion in response to some stronger stimuli, specifically from granules that have not been docked to the plasma membrane. Exophilin7 appears to mediate the fusion of undocked granules through the affinity of its C2A domain toward the plasma membrane phospholipids. These findings indicate that the two Rab27a effectors, granuphilin and exophilin7, differentially regulate the exocytosis of either stably or minimally docked granules, respectively.

ClpP-deletion impairs the virulence of Legionella pneumophila and the optimal translocation of effector proteins.

PubMed

Zhao, Bei-Bei; Li, Xiang-Hui; Zeng, Yong-Lun; Lu, Yong-Jun

2016-08-02

The opportunistic bacterial pathogen Legionella pneumophila uses substrate effectors of Dot/Icm type IVB secretion system (T4BSS) to accomplish survival and replication in amoebae cells and mammalian alveolar macrophages. During the conversion between its highly resistant, infectious dormant form and vigorously growing, uninfectious replicative form, L. pneumophila utilizes a complicated regulatory network in which proteolysis may play a significant role. As a highly conserved core protease, ClpP is involved in various cellular processes as well as virulence in bacteria, and has been proved to be required for the expression of transmission traits and cell division of L. pneumophila. The clpP-deficient L. pneumophila strain failed to replicate and was digested in the first 3 h post-infection in mammalian cells J774A.1. Further investigation demonstrates that the clpP deficient mutant strain was unable to escape the endosome-lysosomal pathway in host cells. We also found that the clpP deficient mutant strain still expresses T4BSS components, induces contact-dependent cytotoxicity and translocate effector proteins RalF and LegK2, indicating that its T4BSS was overall functional. Interestingly, we further found that the translocation of several effector proteins is significantly reduced without ClpP. The data indicate that ClpP plays an important role in regulating the virulence and effector translocation of Legionella pneumophila.

Controlling transcription in human pluripotent stem cells using CRISPR-effectors.

PubMed

Genga, Ryan M; Kearns, Nicola A; Maehr, René

2016-05-15

The ability to manipulate transcription in human pluripotent stem cells (hPSCs) is fundamental for the discovery of key genes and mechanisms governing cellular state and differentiation. Recently developed CRISPR-effector systems provide a systematic approach to rapidly test gene function in mammalian cells, including hPSCs. In this review, we discuss recent advances in CRISPR-effector technologies that have been employed to control transcription through gene activation, gene repression, and epigenome engineering. We describe an application of CRISPR-effector mediated transcriptional regulation in hPSCs by targeting a synthetic promoter driving a GFP transgene, demonstrating the ease and effectiveness of CRISPR-effector mediated transcriptional regulation in hPSCs. Copyright © 2015 Elsevier Inc. All rights reserved.

Cytokines and the Inception of CD8 T Cell Responses

PubMed Central

Cox, Maureen A.; Harrington, Laurie E.; Zajac, Allan J.

2011-01-01

The activation and differentiation of CD8 T cells is a necessary first step that endows these cells with the phenotypic and functional properties required for the control of intracellular pathogens. The induction of the CD8 T cell responses typically results in the development of a massive overall population of effector cells, comprised of both highly functional but short-lived terminally differentiated cells, as well as a smaller subset of precursors that are predisposed to survive and transition into the memory T cell pool. In this article we discuss how inflammatory cytokines and IL-2 bias the initial response towards short-lived effector generation and also highlight the potential counterbalancing role of IL-21. PMID:21371940

Reciprocity between Regulatory T Cells and Th17 Cells: Relevance to Polarized Immunity in Leprosy

PubMed Central

Sadhu, Soumi; Khaitan, Binod Kumar; Joshi, Beenu; Sengupta, Utpal; Nautiyal, Arvind Kumar; Mitra, Dipendra Kumar

2016-01-01

T cell defect is a common feature in lepromatous or borderline lepromatous leprosy (LL/BL) patients in contrast to tuberculoid or borderline tuberculoid type (TT/BT) patients. Tuberculoid leprosy is characterized by strong Th1-type cell response with localized lesions whereas lepromatous leprosy is hallmarked by its selective Mycobacterium leprae specific T cell anergy leading to disseminated and progressive disease. FoxP3+ Regulatory T cells (Treg) which are essential for maintaining peripheral tolerance, preventing autoimmune diseases and limiting chronic inflammatory diseases also dampen proinflammatory T cells that include T helper 17 (Th17) cells. This study is aimed at evaluating the role of Treg cells in influencing other effector T cells and its relationship with the cytokine polarized state in leprosy patients. Peripheral blood mononuclear cells from of BT/TT (n = 15) and BL/LL (n = 15) patients were stimulated with M. leprae antigen (WCL) in presence of golgi transport inhibitor monensin for FACS based intracellular cytokine estimation. The frequency of Treg cells showed >5-fold increase in BL/LL in comparison to BT/TT and healthy contacts. These cells produced suppressive cytokine, IL-10 in BL/LL as opposed to BT/TT (p = 0.0200) indicating their suppressive function. The frequency of Th17 cells (CD4, CD45RO, IL-17) was, however, higher in BT/TT. Significant negative correlation (r = -0.68, P = 0.03) was also found between IL-10 of Treg cells and IL-17+ T cells in BL/LL. Blocking IL-10/TGF-β restored the IL-17+ T cells in BL/LL patients. Simultaneously, presence of Th17 related cytokines (TGF-β, IL-6, IL-17 and IL-23) decreased the number of FoxP3+ Treg cells concomitantly increasing IL-17 producing CD4+ cells in lepromatous leprosy. Higher frequency of Programmed Death-1/PD-1+ Treg cells and its ligand, PDL-1 in antigen presenting cells (APCs) was found in BL/LL patients. Inhibition of this pathway led to rescue of IFN-γ and IL-17 producing T cells. Results indicate that Treg cells are largely responsible for the kind of immunosuppression observed in BL/LL patients. This study also proves that Treg cells are profoundly affected by the cytokine milieu and this property may be utilized for benefit of the host. PMID:26751584

Global impact of Salmonella type III secretion effector SteA on host cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardenal-Muñoz, Elena, E-mail: e_cardenal@us.es; Gutiérrez, Gabriel, E-mail: ggpozo@us.es; Ramos-Morales, Francisco, E-mail: framos@us.es

Highlights: • We analyzed HeLa cells transcriptome in response to Salmonella SteA. • Significant differential expression was detected for 58 human genes. • They are involved in ECM organization and regulation of some signaling pathways. • Cell death, cell adhesion and cell migration were decreased in SteA-expressing cells. • These results contribute to understand the role of SteA during infections. - Abstract: Salmonella enterica is a Gram-negative bacterium that causes gastroenteritis, bacteremia and typhoid fever in several animal species including humans. Its virulence is greatly dependent on two type III secretion systems, encoded in pathogenicity islands 1 and 2. Thesemore » systems translocate proteins called effectors into eukaryotic host cell. Effectors interfere with host signal transduction pathways to allow the internalization of pathogens and their survival and proliferation inside vacuoles. SteA is one of the few Salmonella effectors that are substrates of both type III secretion systems. Here, we used gene arrays and bioinformatics analysis to study the genetic response of human epithelial cells to SteA. We found that constitutive synthesis of SteA in HeLa cells leads to induction of genes related to extracellular matrix organization and regulation of cell proliferation and serine/threonine kinase signaling pathways. SteA also causes repression of genes related to immune processes and regulation of purine nucleotide synthesis and pathway-restricted SMAD protein phosphorylation. In addition, a cell biology approach revealed that epithelial cells expressing steA show altered cell morphology, and decreased cytotoxicity, cell–cell adhesion and migration.« less

The yellow fever virus vaccine induces a broad and polyfunctional human memory CD8+ T cell response.

PubMed

Akondy, Rama S; Monson, Nathan D; Miller, Joseph D; Edupuganti, Srilatha; Teuwen, Dirk; Wu, Hong; Quyyumi, Farah; Garg, Seema; Altman, John D; Del Rio, Carlos; Keyserling, Harry L; Ploss, Alexander; Rice, Charles M; Orenstein, Walter A; Mulligan, Mark J; Ahmed, Rafi

2009-12-15

The live yellow fever vaccine (YF-17D) offers a unique opportunity to study memory CD8(+) T cell differentiation in humans following an acute viral infection. We have performed a comprehensive analysis of the virus-specific CD8(+) T cell response using overlapping peptides spanning the entire viral genome. Our results showed that the YF-17D vaccine induces a broad CD8(+) T cell response targeting several epitopes within each viral protein. We identified a dominant HLA-A2-restricted epitope in the NS4B protein and used tetramers specific for this epitope to track the CD8(+) T cell response over a 2 year period. This longitudinal analysis showed the following. 1) Memory CD8(+) T cells appear to pass through an effector phase and then gradually down-regulate expression of activation markers and effector molecules. 2) This effector phase was characterized by down-regulation of CD127, Bcl-2, CCR7, and CD45RA and was followed by a substantial contraction resulting in a pool of memory T cells that re-expressed CD127, Bcl-2, and CD45RA. 3) These memory cells were polyfunctional in terms of degranulation and production of the cytokines IFN-gamma, TNF-alpha, IL-2, and MIP-1beta. 4) The YF-17D-specific memory CD8(+) T cells had a phenotype (CCR7(-)CD45RA(+)) that is typically associated with terminally differentiated cells with limited proliferative capacity (T(EMRA)). However, these cells exhibited robust proliferative potential showing that expression of CD45RA may not always associate with terminal differentiation and, in fact, may be an indicator of highly functional memory CD8(+) T cells generated after acute viral infections.

Type III secretion system effector proteins: double agents in bacterial disease and plant defense.

PubMed

Alfano, James R; Collmer, Alan

2004-01-01

Many phytopathogenic bacteria inject virulence effector proteins into plant cells via a Hrp type III secretion system (TTSS). Without the TTSS, these pathogens cannot defeat basal defenses, grow in plants, produce disease lesions in hosts, or elicit the hypersensitive response (HR) in nonhosts. Pathogen genome projects employing bioinformatic methods to identify TTSS Hrp regulon promoters and TTSS pathway targeting signals suggest that phytopathogenic Pseudomonas, Xanthomonas, and Ralstonia spp. harbor large arsenals of effectors. The Hrp TTSS employs customized cytoplasmic chaperones, conserved export components in the bacterial envelope (also used by the TTSS of animal pathogens), and a more specialized set of TTSS-secreted proteins to deliver effectors across the plant cell wall and plasma membrane. Many effectors can act as molecular double agents that betray the pathogen to plant defenses in some interactions and suppress host defenses in others. Investigations of the functions of effectors within plant cells have demonstrated the plasma membrane and nucleus as subcellular sites for several effectors, revealed some effectors to possess cysteine protease or protein tyrosine phosphatase activity, and provided new clues to the coevolution of bacterium-plant interactions.

Absence of MyD88 Signaling Induces Donor-Specific Kidney Allograft Tolerance

PubMed Central

Noordmans, Gerda A.; O’Brien, Maya R.; Ma, Jin; Zhao, Cathy Y.; Zhang, Geoff Y.; Kwan, Tony K.T.; Alexander, Stephen I.; Chadban, Steven J.

2012-01-01

Toll-like receptors (TLRs) play a fundamental role in innate immunity and provide a link between innate and adaptive responses to an allograft; however, whether the development of acute and chronic allograft rejection requires TLR signaling is unknown. Here, we studied TLR signaling in a fully MHC-mismatched, life-sustaining murine model of kidney allograft rejection. Mice deficient in the TLR adaptor protein MyD88 developed donor antigen-specific tolerance, which protected them from both acute and chronic allograft rejection and increased their survival after transplantation compared with wild-type controls. Administration of an anti-CD25 antibody to MyD88-deficient recipients depleted CD4+CD25+FoxP3+ cells and broke tolerance. In addition, defective development of Th17 immune responses to alloantigen both in vitro and in vivo occurred, resulting in an increased ratio of Tregs to Th17 effectors. Thus, MyD88 deficiency was associated with an altered balance of Tregs over Th17 cells, promoting tolerance instead of rejection. This study provides evidence that targeting innate immunity may be a clinically relevant strategy to facilitate transplantation tolerance. PMID:22878960

LOCALIZER: subcellular localization prediction of both plant and effector proteins in the plant cell

PubMed Central

Sperschneider, Jana; Catanzariti, Ann-Maree; DeBoer, Kathleen; Petre, Benjamin; Gardiner, Donald M.; Singh, Karam B.; Dodds, Peter N.; Taylor, Jennifer M.

2017-01-01

Pathogens secrete effector proteins and many operate inside plant cells to enable infection. Some effectors have been found to enter subcellular compartments by mimicking host targeting sequences. Although many computational methods exist to predict plant protein subcellular localization, they perform poorly for effectors. We introduce LOCALIZER for predicting plant and effector protein localization to chloroplasts, mitochondria, and nuclei. LOCALIZER shows greater prediction accuracy for chloroplast and mitochondrial targeting compared to other methods for 652 plant proteins. For 107 eukaryotic effectors, LOCALIZER outperforms other methods and predicts a previously unrecognized chloroplast transit peptide for the ToxA effector, which we show translocates into tobacco chloroplasts. Secretome-wide predictions and confocal microscopy reveal that rust fungi might have evolved multiple effectors that target chloroplasts or nuclei. LOCALIZER is the first method for predicting effector localisation in plants and is a valuable tool for prioritizing effector candidates for functional investigations. LOCALIZER is available at http://localizer.csiro.au/. PMID:28300209

Plant parasitic nematode effectors target host defense and nuclear functions to establish feeding cells.

PubMed

Quentin, Michaëel; Abad, Pierre; Favery, Bruno

2013-01-01

Plant parasitic nematodes are microscopic worms, the most damaging species of which have adopted a sedentary lifestyle within their hosts. These obligate endoparasites have a biotrophic relationship with plants, in which they induce the differentiation of root cells into hypertrophied, multinucleate feeding cells (FCs). Effectors synthesized in the esophageal glands of the nematode are injected into the plant cells via the syringe-like stylet and play a key role in manipulating the host machinery. The establishment of specialized FCs requires these effectors to modulate many aspects of plant cell morphogenesis and physiology, including defense responses. This cell reprogramming requires changes to host nuclear processes. Some proteins encoded by parasitism genes target host nuclei. Several of these proteins were immunolocalized within FC nuclei or shown to interact with host nuclear proteins. Comparative genomics and functional analyses are gradually revealing the roles of nematode effectors. We describe here these effectors and their hypothesized roles in the unique feeding behavior of these pests.

Human Naive T Cells Express Functional CXCL8 and Promote Tumorigenesis.

PubMed

Crespo, Joel; Wu, Ke; Li, Wei; Kryczek, Ilona; Maj, Tomasz; Vatan, Linda; Wei, Shuang; Opipari, Anthony W; Zou, Weiping

2018-05-25

Naive T cells are thought to be functionally quiescent. In this study, we studied and compared the phenotype, cytokine profile, and potential function of human naive CD4 + T cells in umbilical cord and peripheral blood. We found that naive CD4 + T cells, but not memory T cells, expressed high levels of chemokine CXCL8. CXCL8 + naive T cells were preferentially enriched CD31 + T cells and did not express T cell activation markers or typical Th effector cytokines, including IFN-γ, IL-4, IL-17, and IL-22. In addition, upon activation, naive T cells retained high levels of CXCL8 expression. Furthermore, we showed that naive T cell-derived CXCL8 mediated neutrophil migration in the in vitro migration assay, supported tumor sphere formation, and promoted tumor growth in an in vivo human xenograft model. Thus, human naive T cells are phenotypically and functionally heterogeneous and can carry out active functions in immune responses. Copyright © 2018 by The American Association of Immunologists, Inc.

The innate defense antimicrobial peptides hBD3 and RNase7 are induced in human umbilical vein endothelial cells by classical inflammatory cytokines but not Th17 cytokines.

PubMed

Burgey, Christine; Kern, Winfried V; Römer, Winfried; Sakinc, Türkan; Rieg, Siegbert

2015-05-01

Antimicrobial peptides are multifunctional effector molecules of innate immunity. In this study we investigated whether endothelial cells actively contribute to innate defense mechanisms by expression of antimicrobial peptides. We therefore stimulated human umbilical vein endothelial cells (HUVEC) with inflammatory cytokines, Th17 cytokines, heat-inactivated bacteria, bacterial conditioned medium (BCM) of Staphylococcus aureus and Streptococcus sanguinis, and lipoteichoic acid (LTA). Stimulation with single cytokines induced discrete expression of human β-defensin 3 (hBD3) by IFN-γ or IL-1β and of ribonuclease 7 (RNase7) by TNF-α without any effects on LL-37 gene expression. Stronger hBD3 and RNase7 induction was observed after combined stimulation with IL-1β, TNF-α and IFN-γ and was confirmed by high hBD3 and RNase7 peptide levels in cell culture supernatants. In contrast, Th17 cytokines or stimulation with LTA did not result in AMP production. Moreover, only BCM of an invasive S. aureus bacteremia isolate induced hBD3 in HUVEC. We conclude that endothelial cells actively contribute to prevent dissemination of pathogens at the blood-tissue-barrier by production of AMPs that exhibit microbicidal and immunomodulatory functions. Further investigations should focus on tissue-specific AMP induction in different endothelial cell types, on pathogen-specific induction patterns and potentially involved pattern-recognition receptors of endothelial cells. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Macrophage-mediated trogocytosis leads to death of antibody-opsonized tumor cells

PubMed Central

Velmurugan, Ramraj; Challa, Dilip K.; Ram, Sripad; Ober, Raimund J.; Ward, E. Sally

2016-01-01

Understanding the complex behavior of effector cells such as monocytes or macrophages in regulating cancerous growth is of central importance for cancer immunotherapy. Earlier studies using CD20-specific antibodies have demonstrated that the Fcγ receptor (FcγR)-mediated transfer of the targeted receptors from tumor cells to these effector cells through trogocytosis can enable escape from antibody therapy, leading to the viewpoint that this process is pro-tumorigenic. In the current study we demonstrate that persistent trogocytic attack results in the killing of HER2-overexpressing breast cancer cells. Further, antibody engineering to increase FcγR interactions enhances this tumoricidal activity. These studies extend the complex repertoire of activities of macrophages to trogocytic-mediated cell death of HER2-overexpressing target cells and have implications for the development of effective antibody-based therapies. PMID:27226489

US_EVA_48_part_1-of-5

NASA Image and Video Library

2018-02-20

Outside the International Space Station, Expedition 54 Flight Engineers Mark Vande Hei of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) conducted a spacewalk to move a Latching End Effector, or hand, for the Canadarm2 robotic arm into the Quest airlock that was removed during another excursion last October and to move a degraded end effector replaced during a Jan. 23 spacewalk onto a payload attachment device on the station’s Mobile Base System railcar. The spacewalk was the 208th in station history for assembly, maintenance and upgrades, the fourth in Vande Hei’s career and the first for Kanai, who became only the fourth Japanese astronaut to walk in space.

Space_Station_Crew_Members_Walk_in_Space_to_Complete_Robotics_Upgrades

NASA Image and Video Library

2018-02-16

Outside the International Space Station, Expedition 54 Flight Engineers Mark Vande Hei of NASA and Norishige Kanai of the Japan Aerospace Exploration Agency (JAXA) conducted a spacewalk to move a Latching End Effector, or hand, for the Canadarm2 robotic arm into the Quest airlock that was removed during another excursion last October and to move a degraded end effector replaced during a Jan. 23 spacewalk onto a payload attachment device on the station’s Mobile Base System railcar. The spacewalk was the 208th in station history for assembly, maintenance and upgrades, the fourth in Vande Hei’s career and the first for Kanai, who became only the fourth Japanese astronaut to walk in space.