Science.gov

Sample records for adaptive t-cell response

  1. gammadelta T cells link innate and adaptive immune responses.

    PubMed

    Holtmeier, Wolfgang; Kabelitz, Dieter

    2005-01-01

    While most T cells use a CD3-associated alpha/beta T cell receptor as antigen recognition structure, a second population of T cells expresses the alternative gamma/delta T cell receptor. gamma/delta T cells are a minor population in the peripheral blood but constitute a major population among intestinal intraepithelial lymphocytes. Most gamma/delta T cells recognize ligands which are fundamentally different from the short peptides that are seen by alpha/beta T cells in the context of MHC class I or class II molecules. Thus, human Vdelta2 T cells recognize small bacterial phosphoantigens, alkylamines and synthetic aminobisphosphonates, whereas Vdelta1 T cells recognize stress-inducible MHC-related molecules MICA/B as well as several other ligands. At the functional level, gamma/delta T cells rapidly produce a variety of cytokines and usually exert potent cytotoxic activity, also towards many tumor cells. In this article, we discuss the role of gamma/delta T cells as a bridge between the innate and the adaptive immune system, based on the interpretation that gamma/delta T cells use their T cell receptor as a pattern recognition receptor. Our increasing understanding of the ligand recognition and activation mechanisms of gamma/delta T cells also opens new perspectives for the development of gamma/delta T cell-based immunotherapies.

  2. Resident memory CD8 T cells trigger protective innate and adaptive immune responses

    PubMed Central

    Schenkel, Jason M.; Fraser, Kathryn A.; Beura, Lalit K.; Pauken, Kristen E.; Vezys, Vaiva; Masopust, David

    2015-01-01

    The pathogen recognition theory dictates that upon viral infection, the innate immune system first detects microbial products, and then responds by providing instructions to adaptive CD8 T cells. Here, we show in mice that resident memory CD8 T cells (TRM), non-recirculating cells located at common sites of infection, can achieve near sterilizing immunity against viral infections by reversing this flow of information. Upon antigen re-sensitization within the mouse female reproductive mucosae, CD8+ TRM secrete cytokines that trigger rapid adaptive and innate immune responses including local humoral responses, maturation of local dendritic cells, and activation of natural killer cells. This provided near sterilizing immunity against an antigenically unrelated viral infection. Thus, CD8+ TRM rapidly trigger an antiviral state by amplifying receptor-derived signals from previously encountered pathogens. PMID:25170049

  3. Innate-like CD4 T cells selected by thymocytes suppress adaptive immune responses against bacterial infections

    PubMed Central

    Qiao, Yu; Gray, Brian M.; Sofi, Mohammed H.; Bauler, Laura D.; Eaton, Kathryn A.; O'Riordan, Mary X. D.; Chang, Cheong-Hee

    2012-01-01

    We have reported a new innate-like CD4 T cell population that expresses cell surface makers of effector/memory cells and produce Th1 and Th2 cytokines immediately upon activation. Unlike conventional CD4 T cells that are selected by thymic epithelial cells, these CD4 T cells, named T-CD4 T cells, are selected by MHC class II expressing thymocytes. Previously, we showed that the presence of T-CD4 T cells protected mice from airway inflammation suggesting an immune regulatory role of T-CD4 T cells. To further understand the function of T-CD4 T cells, we investigated immune responses mediated by T-CD4 T cells during bacterial infection because the generation of antigen specific CD4 T cells contributes to clearance of infection and for the development of immune memory. The current study shows a suppressive effect of T-CD4 T cells on both CD8 and CD4 T cell-mediated immune responses during Listeria and Helicobacter infections. In the mouse model of Listeria monocytogenes infection, T-CD4 T cells resulted in decreasedfrequency of Listeria-specific CD8 T cells and the killing activity of them. Furthermore, mice with T-CD4 T cells developed poor immune memory, demonstrated by reduced expansion of antigen-specific T cells and high bacterial burden upon re-infection. Similarly, the presence of T-CD4 T cells suppressed the generation of antigen-specific CD4 T cells in Helicobacter pylori infected mice. Thus, our studies reveal a novel function of T-CD4 T cells in suppressing anti-bacterial immunity. PMID:23264931

  4. A stochastic T cell response criterion

    PubMed Central

    Currie, James; Castro, Mario; Lythe, Grant; Palmer, Ed; Molina-París, Carmen

    2012-01-01

    The adaptive immune system relies on different cell types to provide fast and coordinated responses, characterized by recognition of pathogenic challenge, extensive cellular proliferation and differentiation, as well as death. T cells are a subset of the adaptive immune cellular pool that recognize immunogenic peptides expressed on the surface of antigen-presenting cells by means of specialized receptors on their membrane. T cell receptor binding to ligand determines T cell responses at different times and locations during the life of a T cell. Current experimental evidence provides support to the following: (i) sufficiently long receptor–ligand engagements are required to initiate the T cell signalling cascade that results in productive signal transduction and (ii) counting devices are at work in T cells to allow signal accumulation, decoding and translation into biological responses. In the light of these results, we explore, with mathematical models, the timescales associated with T cell responses. We consider two different criteria: a stochastic one (the mean time it takes to have had N receptor–ligand complexes bound for at least a dwell time, τ, each) and one based on equilibrium (the time to reach a threshold number N of receptor–ligand complexes). We have applied mathematical models to previous experiments in the context of thymic negative selection and to recent two-dimensional experiments. Our results indicate that the stochastic criterion provides support to the thymic affinity threshold hypothesis, whereas the equilibrium one does not, and agrees with the ligand hierarchy experimentally established for thymic negative selection. PMID:22745227

  5. Human γδ T cells are quickly reconstituted after stem-cell transplantation and show adaptive clonal expansion in response to viral infection.

    PubMed

    Ravens, Sarina; Schultze-Florey, Christian; Raha, Solaiman; Sandrock, Inga; Drenker, Melanie; Oberdörfer, Linda; Reinhardt, Annika; Ravens, Inga; Beck, Maleen; Geffers, Robert; von Kaisenberg, Constantin; Heuser, Michael; Thol, Felicitas; Ganser, Arnold; Förster, Reinhold; Koenecke, Christian; Prinz, Immo

    2017-02-20

    To investigate how the human γδ T cell pool is shaped during ontogeny and how it is regenerated after transplantation of hematopoietic stem cells (HSCs), we applied an RNA-based next-generation sequencing approach to monitor the dynamics of the repertoires of γδ T cell antigen receptors (TCRs) before and after transplantation in a prospective cohort study. We found that repertoires of rearranged genes encoding γδ TCRs (TRG and TRD) in the peripheral blood of healthy adults were stable over time. Although a large fraction of human TRG repertoires consisted of public sequences, the TRD repertoires were private. In patients undergoing HSC transplantation, γδ T cells were quickly reconstituted; however, they had profoundly altered TCR repertoires. Notably, the clonal proliferation of individual virus-reactive γδ TCR sequences in patients with reactivation of cytomegalovirus revealed strong evidence for adaptive anti-viral γδ T cell immune responses.

  6. Innate immunity regulates adaptive immune response: lessons learned from studying the interplay between NK and CD8+ T cells during MCMV infection.

    PubMed

    Mitrović, Maja; Arapović, Jurica; Traven, Luka; Krmpotić, Astrid; Jonjić, Stipan

    2012-11-01

    Natural killer (NK) cells play a crucial role in early immune response against cytomegalovirus infection. A large and mounting body of data indicate that these cells are involved in the regulation of the adaptive immune response as well. By using mouse cytomegalovirus (MCMV) as a model, several groups provided novel insights into the role of NK cells in the development and kinetics of antiviral CD8(+) T cell response. Depending on infection conditions, virus strain and the genetic background of mice used, NK cells are either positive or negative regulators of the CD8(+) T cell response. At present, there is no unique explanation for the observed differences between various experimental systems used. In this review we discuss the mechanisms involved in the interplay between NK and CD8(+) T cells in the early control of MCMV infection.

  7. Innate immunity regulates adaptive immune response: lessons learned from studying the interplay between NK and CD8+ T cells during MCMV infection

    PubMed Central

    Mitrović, Maja; Arapović, Jurica; Traven, Luka; Krmpotić, Astrid; Jonjić, Stipan

    2012-01-01

    Natural killer (NK) cells play a crucial role in early immune response against cytomegalovirus infection. A large and mounting body of data indicate that these cells are involved in the regulation of the adaptive immune response as well. By using mouse cytomegalovirus (MCMV) as a model, several groups provided novel insights into the role of NK cells in the development and kinetics of antiviral CD8+ T cell response. Depending on infection conditions, virus strain and the genetic background of mice used, NK cells are either positive or negative regulators of the CD8+ T cell response. At present, there is no unique explanation for the observed differences between various experimental systems used. In this review we discuss the mechanisms involved in the interplay between NK and CD8+ T cells in the early control of MCMV infection. PMID:22965169

  8. The T Cell Response to Staphylococcus aureus

    PubMed Central

    Bröker, Barbara M.; Mrochen, Daniel; Péton, Vincent

    2016-01-01

    Staphylococcus aureus (S. aureus) is a dangerous pathogen and a leading cause of both nosocomial and community acquired bacterial infection worldwide. However, on the other hand, we are all exposed to this bacterium, often within the first hours of life, and usually manage to establish equilibrium and coexist with it. What does the adaptive immune system contribute toward lifelong control of S. aureus? Will it become possible to raise or enhance protective immune memory by vaccination? While in the past the S. aureus-specific antibody response has dominated this discussion, the research community is now coming to appreciate the role that the cellular arm of adaptive immunity, the T cells, plays. There are numerous T cell subsets, each with differing functions, which together have the ability to orchestrate the immune response to S. aureus and hence to tip the balance between protection and pathology. This review summarizes the state of the art in this dynamic field of research. PMID:26999219

  9. Innate and Adaptive Immune Responses Both Contribute to Pathological CD4 T Cell Activation in HIV-1 Infected Ugandans

    DTIC Science & Technology

    2011-04-01

    Matud JL, Yamashita TE, Mellors JW, et al. (2002) Predictive value of immunologic and virologic markers after long or short duration of HIV-1...of AIDS. Annu Rev Med 60: 471–484. 10. Gonzalez VD, Landay AL, Sandberg JK (2010) Innate immunity and chronic immune activation in HCV /HIV-1 co...rescues the proliferative response of simian immunodeficiency virus-specific CD4 and CD8 T cells during chronic infection. Immunology 124: 277–293. 31

  10. Thiol dependent NF-κB suppression and inhibition of T-cell mediated adaptive immune responses by a naturally occurring steroidal lactone Withaferin A.

    PubMed

    Gambhir, Lokesh; Checker, Rahul; Sharma, Deepak; Thoh, M; Patil, Anand; Degani, M; Gota, Vikram; Sandur, Santosh K

    2015-12-01

    Withaferin A (WA), a steroidal lactone isolated from ayurvedic medicinal plant Withania somnifera, was shown to inhibit tumor growth by inducing oxidative stress and suppressing NF-κB pathway. However, its effect on T-cell mediated adaptive immune responses and the underlying mechanism has not been investigated. Since both T-cell responses and NF-κB pathway are known to be redox sensitive, the present study was undertaken to elucidate the effect of WA on adaptive immune responses in vitro and in vivo. WA inhibited mitogen induced T-cell and B-cell proliferation in vitro without inducing any cell death. It inhibited upregulation of T-cell (CD25, CD69, CD71 and CD54) and B-cell (CD80, CD86 and MHC-II) activation markers and secretion of Th1 and Th2 cytokines. WA induced oxidative stress by increasing the basal ROS levels and the immunosuppressive effects of WA were abrogated only by thiol anti-oxidants. The redox modulatory effects of WA in T-cells were attributed to its ability to directly interact with free thiols. WA inhibited NF-κB nuclear translocation in lymphocytes and prevented the direct binding of nuclear NF-κB to its consensus sequence. MALDI-TOF analysis using a synthetic NF-κB-p50 peptide containing Cys-62 residue suggested that WA can modify the cysteine residue of NF-κB. The pharmacokinetic studies for WA were also carried out and in vivo efficacy of WA was studied using mouse model of Graft-versus-host disease. In conclusion, WA is a potent inhibitor of T-cell responses and acts via a novel thiol dependent mechanism and inhibition of NF-κB pathway.

  11. Regulating the adaptive immune response to blood-stage malaria: role of dendritic cells and CD4⁺Foxp3⁺ regulatory T cells.

    PubMed

    Stevenson, Mary M; Ing, Rebecca; Berretta, Floriana; Miu, Jenny

    2011-01-01

    Although a clearer understanding of the underlying mechanisms involved in protection and immunopathology during blood-stage malaria has emerged, the mechanisms involved in regulating the adaptive immune response especially those required to maintain a balance between beneficial and deleterious responses remain unclear. Recent evidence suggests the importance of CD11c⁺ dendritic cells (DC) and CD4⁺Foxp3⁺ regulatory T cells in regulating immune responses during infection and autoimmune disease, but information concerning the contribution of these cells to regulating immunity to malaria is limited. Here, we review recent findings from our laboratory and others in experimental models of malaria in mice and in Plasmodium-infected humans on the roles of DC and natural regulatory T cells in regulating adaptive immunity to blood-stage malaria.

  12. T Cell Responses to Arenavirus Infections.

    DTIC Science & Technology

    1991-11-01

    FIELD GROUP SUB-GROUP T cells; Arenaviruses ; Hemorrhagic fevers, Lassa fever, 06 13 LCMV Lassa fever virus; Synthetic peptides; Vaccine; I Recombinant...virus-specific effector T cells and that some of the T cell determinants they recognize are conserved among O.W. arenaviruses . For example, Jahrling...specific T cells were not represented by these peptides. fl4AM17.817073 (MFBM24) CONCLUSIONS Our knowledge of the immune response to arenaviruses is

  13. Dysregulation of Toll-Like Receptor 7 Compromises Innate and Adaptive T Cell Responses and Host Resistance to an Attenuated West Nile Virus Infection in Old Mice

    PubMed Central

    Xie, Guorui; Luo, Huanle; Pang, Lan; Peng, Bi-hung; Winkelmann, Evandro; McGruder, Brenna; Hesse, Joseph; Whiteman, Melissa; Campbell, Gerald; Milligan, Gregg N.; Cong, Yingzi; Barrett, Alan D.

    2015-01-01

    ABSTRACT The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), a mosquito-borne flavivirus, has induced severe neurological symptoms, mostly in the elderly population. No vaccines are available for human use. Recent work showed that an attenuated WNV, a nonstructural (NS) 4B-P38G mutant, induced no lethality but strong immune responses in young (6- to 10-week-old) mice. While studying protective efficacy, we found unexpectedly that old (21- to 22-month) mice were susceptible to WNV NS4B-P38G mutant infection but were protected from subsequent lethal wild-type WNV challenge. Compared to responses in young mice, the NS4B-P38G mutant triggered higher inflammatory cytokine and interleukin-10 (IL-10) production, a delayed γδ T cell expansion, and lower antibody and WNV-specific T cell responses in old mice. Toll-like receptor 7 (TLR7) is expressed on multiple types of cells. Impaired TLR7 signaling in old mice led to dendritic cell (DC) antigen-presenting function compromise and a reduced γδ T cell and regulatory T cell (Treg) expansion during NS4B-P38G mutant infection. R848, a TLR7 agonist, decreased host vulnerability in NS4B-P38G-infected old mice by enhancing γδ T cell and Treg expansion and the antigen-presenting capacity of DCs, thereby promoting T cell responses. In summary, our results suggest that dysregulation of TLR7 partially contributes to impaired innate and adaptive T cell responses and an enhanced vulnerability in old mice during WNV NS4B-P38G mutant infection. R848 increases the safety and efficacy during immunization of old mice with the WNV NS4B-P38G mutant. IMPORTANCE The elderly are known to have enhanced susceptibility to infections and an impaired capacity to respond to vaccination. West Nile virus (WNV), an emerging mosquito-borne flavivirus, has induced severe neurological symptoms more frequently in the elderly population. No vaccines are available

  14. Infection with a Mouse-Adapted Strain of the 2009 Pandemic Virus Causes a Highly Severe Disease Associated with an Impaired T Cell Response

    PubMed Central

    Meunier, Isabelle; Morisseau, Olivier; Garneau, Émilie; Marois, Isabelle; Cloutier, Alexandre; Richter, Martin V.

    2015-01-01

    Despite a relatively low fatality rate, the 2009 H1N1 pandemic virus differed from other seasonal viruses in that it caused mortality and severe pneumonia in the young and middle-aged population (18–59 years old). The mechanisms underlying this increased disease severity are still poorly understood. In this study, a human isolate of the 2009 H1N1 pandemic virus was adapted to the mouse (MAp2009). The pathogenicity of the MAp2009 virus and the host immune responses were evaluated in the mouse model and compared to the laboratory H1N1 strain A/Puerto Rico/8/1934 (PR8). The MAp2009 virus reached consistently higher titers in the lungs over 14 days compared to the PR8 virus, and caused severe disease associated with high morbidity and 85% mortality rate, contrasting with the 0% death rate in the PR8 group. During the early phase of infection, both viruses induced similar pathology in the lungs. However, MAp2009-induced lung inflammation was sustained until the end of the study (day 14), while there was no sign of inflammation in the PR8-infected group by day 10. Furthermore, at day 3 post-infection, MAp2009 induced up to 10- to 40-fold more cytokine and chemokine gene expression, respectively. More importantly, the numbers of CD4+ T cells and virus-specific CD8+ T cells were significantly lower in the lungs of MAp2009-infected mice compared to PR8-infected mice. Interestingly, there was no difference in the number of dendritic cells in the lung and in the draining lymph node. Moreover, mice infected with PR8 or MAp2009 had similar numbers of CCR5 and CXCR3-expressing T cells, suggesting that the impaired T cell response was not due to a lack of chemokine responsiveness or priming of T cells. This study demonstrates that a mouse-adapted virus from an isolate of the 2009 pandemic virus interferes with the adaptive immune response leading to a more severe disease. PMID:26381265

  15. T Cell Responses during Influenza Infection: Getting and Keeping Control

    PubMed Central

    Kim, Taeg S.; Sun, Jie; Braciale, Thomas J.

    2011-01-01

    The 2009 influenza pandemic highlights the threat that type A influenza poses to human health. Thus there is an urgency to understand the pathobiology of influenza infection and the contribution of the host immune response to both virus elimination and the development of lung injury. This review focuses on the T cell arm of the adaptive host immune response to influenza and assesses recent developments in our understanding of the induction of primary influenza virus-specific T cell responses by antigen-presenting cells, the interaction of activated effector T cells with antigen-bearing cells in the infected lungs, and the contribution of influenza-specific effector T cells to the development and control of lung injury and inflammation during infection. PMID:21435950

  16. CD4+ regulatory T cell responses induced by T cell vaccination in patients with multiple sclerosis

    PubMed Central

    Hong, Jian; Zang, Ying C. Q.; Nie, Hong; Zhang, Jingwu Z.

    2006-01-01

    Immunization with irradiated autologous T cells (T cell vaccination) is shown to induce regulatory T cell responses that are poorly understood. In this study, CD4+ regulatory T cell lines were generated from patients with multiple sclerosis that received immunization with irradiated autologous myelin basic protein-reactive T cells. The resulting CD4+ regulatory T cell lines had marked inhibition on autologous myelin basic protein-reactive T cells and displayed two distinctive patterns distinguishable by the expression of transcription factor Foxp3 and cytokine profile. The majority of the T cell lines had high Foxp3 expression and secreted both IFN-γ and IL-10 as compared with the other pattern characteristic of low Foxp3 expression and predominant production of IL-10 but not IFN-γ. CD4+ regulatory T cell lines of both patterns expressed CD25 and reacted with activated autologous T cells but not resting T cells, irrespective of antigen specificity of the target T cells. It was evident that they recognized preferentially a synthetic peptide corresponding to residues 61–73 of the IL-2 receptor α chain. T cell vaccination correlated with increased Foxp3 expression and T cell reactivity to peptide 61–73. The findings have important implications in the understanding of the role of CD4+ regulatory T cell response induced by T cell vaccination. PMID:16547138

  17. Aggregation of human recombinant monoclonal antibodies influences the capacity of dendritic cells to stimulate adaptive T-cell responses in vitro.

    PubMed

    Rombach-Riegraf, Verena; Karle, Anette C; Wolf, Babette; Sordé, Laetitia; Koepke, Stephan; Gottlieb, Sascha; Krieg, Jennifer; Djidja, Marie-Claude; Baban, Aida; Spindeldreher, Sebastian; Koulov, Atanas V; Kiessling, Andrea

    2014-01-01

    Subvisible proteinaceous particles which are present in all therapeutic protein formulations are in the focus of intense discussions between health authorities, academics and biopharmaceutical companies in the context of concerns that such particles could promote unwanted immunogenicity via anti-drug antibody formation. In order to provide further understanding of the subject, this study closely examines the specific biological effects proteinaceous particles may exert on dendritic cells (DCs) as the most efficient antigen-presenting cell population crucial for the initiation of the adaptive immune response. Two different model IgG antibodies were subjected to three different types of exaggerated physical stress to generate subvisible particles in far greater concentrations than the ones typical for the currently marketed biotherapeutical antibodies. The aggregated samples were used in in vitro biological assays in order to interrogate the early DC-driven events that initiate CD4 T-cell dependent humoral adaptive immune responses--peptide presentation capacity and co-stimulatory activity of DCs. Most importantly, antigen presentation was addressed with a unique approach called MHC-associated Peptide Proteomics (MAPPs), which allows for identifying the sequences of HLA-DR associated peptides directly from human dendritic cells. The experiments demonstrated that highly aggregated solutions of two model mAbs generated under controlled conditions can induce activation of human monocyte-derived DCs as indicated by upregulation of typical maturation markers including co-stimulatory molecules necessary for CD4 T-cell activation. Additional data suggest that highly aggregated proteins could induce in vitro T-cell responses. Intriguingly, strong aggregation-mediated changes in the pattern and quantity of antigen-derived HLA-DR associated peptides presented on DCs were observed, indicating a change in protein processing and presentation. Increasing the amounts of subvisible

  18. T cell responses and dengue haemorrhagic fever.

    PubMed

    Screaton, Gavin; Mongkolsapaya, Juthathip

    2006-01-01

    The enhancement of severe disease upon secondary infection makes dengue almost unique among infectious pathogens and presents a serious challenge to vaccine design. Several key observations have been made which shed light onto this phenomenon particularly that antibodies can enhance Fc receptor-dependent uptake of virus into macrophages thereby increasing virus replication. Furthermore there seems to be a relationship between the peak virus load and disease severity. However, a second key feature of dengue is that the life-threatening symptoms do not correlate with the period of high viraemia; instead they occur at a time when the virus load is in steep decline. The coincidence of severe disease manifestations with defervescence and virus control suggests that the symptoms may be a consequence of the immune response to the virus rather than virus induced cytopathology. One of the key elements in the immune response to viruses are T cells which can both secrete a host of inflammatory cytokines and also be directly cytotoxic to infected cells. There are a number of experimental models of T cell-induced immunopathology including in responses to viruses. Particularly interesting in this respect are models of RSV-induced immunopathology, which have direct relevance to vaccine design as a formalin-inactivated vaccine to RSV actually enhanced disease in children when they became naturally infected with RSV, an echo of the disease enhancement seen in dengue. We will present an analysis of CD8+ T cell responses to a number of novel T cell epitopes during dengue infection and also analyse the function and cytokine secretion of these cells. We suggest that an exaggerated and partially misdirected T cell response seen in secondary dengue infection may be part of the complex series of events leading to dengue haemorrhagic fever and shock.

  19. Persistence and Adaptation in Immunity: T Cells Balance the Extent and Thoroughness of Search

    PubMed Central

    Fricke, G. Matthew; Letendre, Kenneth A.; Moses, Melanie E.; Cannon, Judy L.

    2016-01-01

    Effective search strategies have evolved in many biological systems, including the immune system. T cells are key effectors of the immune response, required for clearance of pathogenic infection. T cell activation requires that T cells encounter antigen-bearing dendritic cells within lymph nodes, thus, T cell search patterns within lymph nodes may be a crucial determinant of how quickly a T cell immune response can be initiated. Previous work suggests that T cell motion in the lymph node is similar to a Brownian random walk, however, no detailed analysis has definitively shown whether T cell movement is consistent with Brownian motion. Here, we provide a precise description of T cell motility in lymph nodes and a computational model that demonstrates how motility impacts T cell search efficiency. We find that both Brownian and Lévy walks fail to capture the complexity of T cell motion. Instead, T cell movement is better described as a correlated random walk with a heavy-tailed distribution of step lengths. Using computer simulations, we identify three distinct factors that contribute to increasing T cell search efficiency: 1) a lognormal distribution of step lengths, 2) motion that is directionally persistent over short time scales, and 3) heterogeneity in movement patterns. Furthermore, we show that T cells move differently in specific frequently visited locations that we call “hotspots” within lymph nodes, suggesting that T cells change their movement in response to the lymph node environment. Our results show that like foraging animals, T cells adapt to environmental cues, suggesting that adaption is a fundamental feature of biological search. PMID:26990103

  20. Shaping of Peripheral T Cell Responses by Lymphatic Endothelial Cells

    PubMed Central

    Humbert, Marion; Hugues, Stéphanie; Dubrot, Juan

    2017-01-01

    Lymph node stromal cells (LNSCs) have newly been promoted to the rank of new modulators of T cell responses. The different non-hematopoietic cell subsets in lymph node (LN) were considered for years as a simple scaffold, forming routes and proper environment for antigen (Ag)-lymphocyte encountering. Deeper characterization of those cells has recently clearly shown their impact on both dendritic cell and T cell functions. In particular, lymphatic endothelial cells (LECs) control lymphocyte trafficking and homeostasis in LNs and limit adaptive immune responses. Therefore, the new role of LECs in shaping immune responses has drawn the attention of immunologists. Striking is the discovery that LECs, among other LNSCs, ectopically express a large range of peripheral tissue-restricted Ags (PTAs), and further present PTA-derived peptides through major histocompatibility class I molecules to induce self-reactive CD8+ T cell deletional tolerance. In addition, both steady-state and tumor-associated LECs were described to be capable of exogenous Ag cross-presentation. Whether LECs can similarly impact CD4+ T cell responses through major histocompatibility class II restricted Ag presentation is still a matter of debate. Here, we review and discuss our current knowledge on the contribution of Ag-presenting LECs as regulators of peripheral T cell responses in different immunological contexts, including autoimmunity and cancer. PMID:28127298

  1. Connecting the innate and adaptive immune responses in mouse choroidal neovascularization via the anaphylatoxin C5a and γδT-cells

    PubMed Central

    Coughlin, Beth; Schnabolk, Gloriane; Joseph, Kusumam; Raikwar, Himanshu; Kunchithapautham, Kannan; Johnson, Krista; Moore, Kristi; Wang, Yi; Rohrer, Bärbel

    2016-01-01

    Neovascular age-related macular degeneration (AMD) is characterized by choroidal neovascularization (CNV). An overactive complement system is associated with AMD pathogenesis, and serum pro-inflammatory cytokines, including IL-17, are elevated in AMD patients. IL-17 is produced by complement C5a-receptor-expressing T-cells. In murine CNV, infiltrating γδT- rather than Th17-cells produce the IL-17 measurable in lesioned eyes. Here we asked whether C5a generated locally in response to CNV recruits IL-17-producing T-cells to the eye. CNV lesions were generated using laser photocoagulation and quantified by imaging; T-lymphocytes were characterized by QRT-PCR. CNV resulted in an increase in splenic IL-17-producing γδT- and Th17-cells; yet in the CNV eye, only elevated levels of γδT-cells were observed. Systemic administration of anti-C5- or anti-C5a-blocking antibodies blunted the CNV-induced production of splenic Th17- and γδT-cells, reduced CNV size and eliminated ocular γδT-cell infiltration. In ARPE-19 cell monolayers, IL-17 triggered a pro-inflammatory state; and splenocyte proliferation was elevated in response to ocular proteins. Thus, we demonstrated that CNV lesions trigger a systemic immune response, augmenting local ocular inflammation via the infiltration of IL-17-producing γδT-cells, which are presumably recruited to the eye in a C5a-dependent manner. Understanding the complexity of complement-mediated pathological mechanisms will aid in the development of an AMD treatment. PMID:27029558

  2. T cell intrinsic roles of autophagy in promoting adaptive immunity

    PubMed Central

    Walsh, Craig M.; Bell, Bryan D.

    2010-01-01

    Autophagy, an ancient cellular response where autophagic vacuoles are formed within the cytosol, is induced in response to a variety of cellular insults, including growth factor or nutrient withdrawal, organelle damage and misfolded proteins. Autophagy is rapidly induced in T lymphocytes following antigenic stimulation and blockade of autophagic signaling greatly reduces T cell clonal expansion, suggesting that autophagy is primarily involved in promoting T cell survival. In contrast, a recently identified negative feedback loop involving FADD and caspase-8, limits the level of autophagy in T cells. Failure to activate caspase-8 during T cell mitogenesis leads to hyperactive autophagy and cellular death through a programmed necrotic mechanism. These findings suggest that crosstalk between these cellular processes is essential for T cell activation and homeostasis. PMID:20392618

  3. Nutrient and Metabolic Sensing in T Cell Responses

    PubMed Central

    Wei, Jun; Raynor, Jana; Nguyen, Thanh-Long M.; Chi, Hongbo

    2017-01-01

    T cells play pivotal roles in shaping host immune responses in infectious diseases, autoimmunity, and cancer. The activation of T cells requires immune and growth factor-derived signals. However, alterations in nutrients and metabolic signals tune T cell responses by impinging upon T cell fates and immune functions. In this review, we summarize how key nutrients, including glucose, amino acids, and lipids, and their sensors and transporters shape T cell responses. We also briefly discuss regulation of T cell responses by oxygen and energy sensing mechanisms. PMID:28337199

  4. Regulatory T Cell Responses in Participants with Type 1 Diabetes after a Single Dose of Interleukin-2: A Non-Randomised, Open Label, Adaptive Dose-Finding Trial

    PubMed Central

    Todd, John A.; Porter, Linsey; Smyth, Deborah J.; Rainbow, Daniel B.; Ferreira, Ricardo C.; Yang, Jennie H.; Bell, Charles J. M.; Schuilenburg, Helen; Challis, Ben; Clarke, Pamela; Coleman, Gillian; Dawson, Sarah; Goymer, Donna; Kennet, Jane; Brown, Judy; Greatorex, Jane; Goodfellow, Ian; Evans, Mark; Mander, Adrian P.; Bond, Simon; Wicker, Linda S.

    2016-01-01

    Background Interleukin-2 (IL-2) has an essential role in the expansion and function of CD4+ regulatory T cells (Tregs). Tregs reduce tissue damage by limiting the immune response following infection and regulate autoreactive CD4+ effector T cells (Teffs) to prevent autoimmune diseases, such as type 1 diabetes (T1D). Genetic susceptibility to T1D causes alterations in the IL-2 pathway, a finding that supports Tregs as a cellular therapeutic target. Aldesleukin (Proleukin; recombinant human IL-2), which is administered at high doses to activate the immune system in cancer immunotherapy, is now being repositioned to treat inflammatory and autoimmune disorders at lower doses by targeting Tregs. Methods and Findings To define the aldesleukin dose response for Tregs and to find doses that increase Tregs physiologically for treatment of T1D, a statistical and systematic approach was taken by analysing the pharmacokinetics and pharmacodynamics of single doses of subcutaneous aldesleukin in the Adaptive Study of IL-2 Dose on Regulatory T Cells in Type 1 Diabetes (DILT1D), a single centre, non-randomised, open label, adaptive dose-finding trial with 40 adult participants with recently diagnosed T1D. The primary endpoint was the maximum percentage increase in Tregs (defined as CD3+CD4+CD25highCD127low) from the baseline frequency in each participant measured over the 7 d following treatment. There was an initial learning phase with five pairs of participants, each pair receiving one of five pre-assigned single doses from 0.04 × 106 to 1.5 × 106 IU/m2, in order to model the dose-response curve. Results from each participant were then incorporated into interim statistical modelling to target the two doses most likely to induce 10% and 20% increases in Treg frequencies. Primary analysis of the evaluable population (n = 39) found that the optimal doses of aldesleukin to induce 10% and 20% increases in Tregs were 0.101 × 106 IU/m2 (standard error [SE] = 0.078, 95% CI = −0

  5. The α4 Nicotinic Receptor Promotes CD4+ T-Cell Proliferation and a Helper T-Cell Immune Response

    PubMed Central

    Nordman, Jacob C.; Muldoon, Pretal; Clark, Sarah; Damaj, M. Imad

    2014-01-01

    Smoking is a common addiction and a leading cause of disease. Chronic nicotine exposure is known to activate nicotinic acetylcholine receptors (nAChRs) in immune cells. We demonstrate a novel role for α4 nAChRs in the effect of nicotine on T-cell proliferation and immunity. Using cell-based sorting and proteomic analysis we define an α4 nAChR expressing helper T-cell population (α4+CD3+CD4+) and show that this group of cells is responsive to sustained nicotine exposure. In the circulation, spleen, bone marrow, and thymus, we find that nicotine promotes an increase in CD3+CD4+ cells via its activation of the α4 nAChR and regulation of G protein subunit o, G protein regulated–inducer of neurite outgrowth, and CDC42 signaling within T cells. In particular, nicotine is found to promote a helper T cell 2 adaptive immunologic response within T cells that is absent in α4−/− mice. We thus present a new mechanism of α4 nAChR signaling and immune regulation in T cells, possibly accounting for the effect of smoking on the immune system. PMID:24107512

  6. Design of T cell receptor libraries with diverse binding properties to examine adoptive T cell responses

    PubMed Central

    Chervin, A.S.; Stone, J.D.; Soto, C.M.; Engels, B.; Schreiber, H.; Roy, E.J.; Kranz, D.M.

    2017-01-01

    Adoptive T cell therapies have shown significant promise in the treatment of cancer and viral diseases. One approach, that introduces antigen-specific T cell receptors (TCRs) into ex vivo activated T cells, is designed to overcome central tolerance mechanisms that prevent responses by endogenous T cell repertoires. Studies have suggested that use of higher affinity TCRs against class I MHC antigens could drive the activity of both CD4+ and CD8+ T cells, but the rules that govern the TCR binding optimal for in vivo activity are unknown. Here we describe a high-throughput platform of “reverse biochemistry” whereby a library of TCRs with a wide range of binding properties to the same antigen is introduced into T cells and adoptively transferred into mice with antigen-positive tumors. Extraction of RNA from tumor-infiltrating lymphocytes or lymphoid organs allowed high-throughput sequencing to determine which TCRs were selected in vivo. The results showed that CD8+ T cells expressing the highest affinity TCR variants were deleted in both the tumor infiltrating lymphocyte population and in peripheral lymphoid tissues. In contrast, these same high-affinity TCR variants were preferentially expressed within CD4+ T cells in the tumor, suggesting they played a role in antigen-specific tumor control. The findings thus revealed that the affinity of the transduced TCRs controlled the survival and tumor infiltration of the transferred T cells. Accordingly, the TCR library strategy enables rapid assessment of TCR binding properties that promote peripheral T cell survival and tumor elimination. PMID:23052828

  7. Vitamin A Deficiency Impairs Adaptive B and T Cell Responses to a Prototype Monovalent Attenuated Human Rotavirus Vaccine and Virulent Human Rotavirus Challenge in a Gnotobiotic Piglet Model

    PubMed Central

    Chattha, Kuldeep S.; Kandasamy, Sukumar; Vlasova, Anastasia N.; Saif, Linda J.

    2013-01-01

    Rotaviruses (RV) are a major cause of gastroenteritis in children. Widespread vitamin A deficiency is associated with reduced efficacy of vaccines and higher incidence of diarrheal infections in children in developing countries. We established a vitamin A deficient (VAD) gnotobiotic piglet model that mimics subclinical vitamin A deficiency in children to study its effects on an oral human rotavirus (HRV) vaccine and virulent HRV challenge. Piglets derived from VAD and vitamin A sufficient (VAS) sows were orally vaccinated with attenuated HRV or mock, with/without supplemental vitamin A and challenged with virulent HRV. Unvaccinated VAD control piglets had significantly lower hepatic vitamin A, higher severity and duration of diarrhea and HRV fecal shedding post-challenge as compared to VAS control pigs. Reduced protection coincided with significantly higher innate (IFNα) cytokine and CD8 T cell frequencies in the blood and intestinal tissues, higher pro-inflammatory (IL12) and 2-3 fold lower anti-inflammatory (IL10) cytokines, in VAD compared to VAS control pigs. Vaccinated VAD pigs had higher diarrhea severity scores compared to vaccinated VAS pigs, which coincided with lower serum IgA HRV antibody titers and significantly lower intestinal IgA antibody secreting cells post-challenge in the former groups suggesting lower anamnestic responses. A trend for higher serum HRV IgG antibodies was observed in VAD vs VAS vaccinated groups post-challenge. The vaccinated VAD (non-vitamin A supplemented) pigs had significantly higher serum IL12 (PID2) and IFNγ (PID6) compared to vaccinated VAS groups suggesting higher Th1 responses in VAD conditions. Furthermore, regulatory T-cell responses were compromised in VAD pigs. Supplemental vitamin A in VAD pigs did not fully restore the dysregulated immune responses to AttHRV vaccine or moderate virulent HRV diarrhea. Our findings suggest that that VAD in children in developing countries may partially contribute to more severe

  8. Reprogramming the T cell response to Tuberculosis

    PubMed Central

    Woodworth, Joshua S.; Andersen, Peter

    2016-01-01

    Recently, Coscolla, Copin et al. use comparative genomics of M.tuberculosis strains to show that most human T cell-recognized epitopes are hyperconserved, but bona fide variable epitopes also exist. This identification of two sets of antigens implies opposing evolutionary processes and has an important impact on Tuberculosis vaccine strategy and design. PMID:26777728

  9. The architects of B and T cell immune responses.

    PubMed

    Lane, Peter J L

    2008-08-15

    Published work links adult lymphoid tissue-inducer cells (LTi) with T cell-dependent antibody responses. In this issue of Immunity, Tsuji et al. (2008) associate LTi with T cell-independent IgA antibody responses in the gut.

  10. Distinct CD4 T-cell effects on primary versus recall CD8 T-cell responses during viral encephalomyelitis

    PubMed Central

    Hwang, Mihyun; Phares, Timothy W; Hinton, David R; Stohlman, Stephen A; Bergmann, Cornelia C; Min, Booki

    2015-01-01

    CD4 T-cell help is not a universal requirement for effective primary CD8 T cells but is essential to generate memory CD8 T cells capable of recall responses. This study examined how CD4 T cells affect primary and secondary anti-viral CD8 T-cell responses within the central nervous system (CNS) during encephalomyelitis induced by sublethal gliatropic coronavirus. CD4 T-cell depletion before infection did not impair peripheral expansion, interferon-γ production, CNS recruitment or initial CNS effector capacity of virus-specific CD8 T cells ex vivo. Nevertheless, impaired virus control in the absence of CD4 T cells was associated with gradually diminished CNS CD8 T-cell interferon-γ production. Furthermore, within the CD8 T-cell population short-lived effector cells were increased and memory precursor effector cells were significantly decreased, consistent with higher T-cell turnover. Transfer of memory CD8 T cells to reduce viral load in CD4-depleted mice reverted the recipient CNS CD8 T-cell phenotype to that in wild-type control mice. However, memory CD8 T cells primed without CD4 T cells and transferred into infected CD4-sufficient recipients expanded less efficiently and were not sustained in the CNS, contrasting with their helped counterparts. These data suggest that CD4 T cells are dispensable for initial expansion, CNS recruitment and differentiation of primary resident memory CD8 T cells as long as the duration of antigen exposure is limited. By contrast, CD4 T cells are essential to prolong primary CD8 T-cell function in the CNS and imprint memory CD8 T cells for recall responses. PMID:25187405

  11. The role of adapter proteins in T cell activation.

    PubMed

    Koretzky, G A; Boerth, N J

    1999-12-01

    Engagement of antigen receptors on lymphocytes leads to a myriad of complex signal transduction cascades. Recently, work from several laboratories has led to the identification and characterization of novel adapter molecules, proteins with no intrinsic enzymatic activity but which integrate signal transduction pathways by mediating protein-protein interactions. Interestingly, it appears that many of these adapter proteins play as critical a role as the effector enzymes themselves in both lymphocyte development and activation. This review describes some of the biochemical and molecular features of several of these newly identified hematopoietic cell-specific adapter molecules highlighting their importance in regulating (both positively and negatively) signal transduction mediated by the T cell antigen receptor.

  12. T Cell Responses: Naive to Memory and Everything in Between

    ERIC Educational Resources Information Center

    Pennock, Nathan D.; White, Jason T.; Cross, Eric W.; Cheney, Elizabeth E.; Tamburini, Beth A.; Kedl, Ross M.

    2013-01-01

    The authors describe the actions that take place in T cells because of their amazing capacity to proliferate and adopt functional roles aimed at clearing a host of an infectious agent. There is a drastic decline in the T cell population once the primary response is over and the infection is terminated. What remains afterward is a population of T…

  13. Chaperone-mediated autophagy regulates T cell responses through targeted degradation of negative regulators of T cell activation.

    PubMed

    Valdor, Rut; Mocholi, Enric; Botbol, Yair; Guerrero-Ros, Ignacio; Chandra, Dinesh; Koga, Hiroshi; Gravekamp, Claudia; Cuervo, Ana Maria; Macian, Fernando

    2014-11-01

    Chaperone-mediated autophagy (CMA) targets soluble proteins for lysosomal degradation. Here we found that CMA was activated in T cells in response to engagement of the T cell antigen receptor (TCR), which induced expression of the CMA-related lysosomal receptor LAMP-2A. In activated T cells, CMA targeted the ubiquitin ligase Itch and the calcineurin inhibitor RCAN1 for degradation to maintain activation-induced responses. Consequently, deletion of the gene encoding LAMP-2A in T cells caused deficient in vivo responses to immunization or infection with Listeria monocytogenes. Impaired CMA activity also occurred in T cells with age, which negatively affected their function. Restoration of LAMP-2A in T cells from old mice resulted in enhancement of activation-induced responses. Our findings define a role for CMA in regulating T cell activation through the targeted degradation of negative regulators of T cell activation.

  14. IL-22 dampens the T cell response in experimental malaria.

    PubMed

    Sellau, Julie; Alvarado, Catherine Fuentes; Hoenow, Stefan; Mackroth, Maria Sophie; Kleinschmidt, Dörte; Huber, Samuel; Jacobs, Thomas

    2016-06-17

    A tight regulation between the pro- and anti-inflammatory immune responses during plasmodial infection is of crucial importance, since a disruption leads to severe malaria pathology. IL-22 is a member of the IL-10 cytokine family, which is known to be highly important in immune regulation. We could detect high plasma levels of IL-22 in Plasmodium falciparum malaria as well as in Plasmodium berghei ANKA (PbA)-infected C57BL/6J mice. The deficiency of IL-22 in mice during PbA infection led to an earlier occurrence of cerebral malaria but is associated with a lower parasitemia compared to wt mice. Furthermore, at an early time point of infection T cells from PbA-infected Il22(-/-) mice showed an enhanced IFNγ but a diminished IL-17 production. Moreover, dendritic cells from Il22(-/-) mice expressed a higher amount of the costimulatory ligand CD86 upon infection. This finding can be corroborated in vitro since bone marrow-derived dendritic cells from Il22(-/-) mice are better inducers of an antigen-specific IFNγ response by CD8(+) T cells. Even though there is no IL-22 receptor complex known on hematopoietic cells, our data suggest a link between IL-22 and the adaptive immune system which is currently not identified.

  15. IL-22 dampens the T cell response in experimental malaria

    PubMed Central

    Sellau, Julie; Alvarado, Catherine Fuentes; Hoenow, Stefan; Mackroth, Maria Sophie; Kleinschmidt, Dörte; Huber, Samuel; Jacobs, Thomas

    2016-01-01

    A tight regulation between the pro– and anti–inflammatory immune responses during plasmodial infection is of crucial importance, since a disruption leads to severe malaria pathology. IL-22 is a member of the IL-10 cytokine family, which is known to be highly important in immune regulation. We could detect high plasma levels of IL-22 in Plasmodium falciparum malaria as well as in Plasmodium berghei ANKA (PbA)-infected C57BL/6J mice. The deficiency of IL-22 in mice during PbA infection led to an earlier occurrence of cerebral malaria but is associated with a lower parasitemia compared to wt mice. Furthermore, at an early time point of infection T cells from PbA-infected Il22−/− mice showed an enhanced IFNγ but a diminished IL-17 production. Moreover, dendritic cells from Il22−/− mice expressed a higher amount of the costimulatory ligand CD86 upon infection. This finding can be corroborated in vitro since bone marrow-derived dendritic cells from Il22−/− mice are better inducers of an antigen-specific IFNγ response by CD8+ T cells. Even though there is no IL-22 receptor complex known on hematopoietic cells, our data suggest a link between IL-22 and the adaptive immune system which is currently not identified. PMID:27311945

  16. Requirements for effective antitumor responses of TCR transduced T cells.

    PubMed

    de Witte, Moniek A; Jorritsma, Annelies; Kaiser, Andrew; van den Boom, Marly D; Dokter, Maarten; Bendle, Gavin M; Haanen, John B A G; Schumacher, Ton N M

    2008-10-01

    Adoptive transfer of TCR gene-modified T cells has been proposed as an attractive approach to target tumors for which it is difficult or impossible to induce strong tumor-specific T cell responses by vaccination. Whereas the feasibility of generating tumor Ag-specific T cells by gene transfer has been demonstrated, the factors that determine the in vivo effectiveness of TCR-modified T cells are largely unknown. We have analyzed the value of a number of clinically feasible strategies to enhance the antitumor potential of TCR modified T cells. These experiments reveal three factors that contribute greatly to the in vivo potency of TCR-modified T cells. First, irradiation-induced host conditioning is superior to vaccine-induced activation of genetically modified T cells. Second, increasing TCR expression through genetic optimization of TCR sequences has a profound effect on in vivo antitumor activity. Third, a high precursor frequency of TCR modified T cells within the graft is essential. Tumors that ultimately progress in animals treated with this optimized regimen for TCR-based adoptive cell transfer invariably display a reduced expression of the target Ag. This suggests TCR gene therapy can achieve a sufficiently strong selective pressure to warrant the simultaneous targeting of multiple Ags. The strategies outlined in this study should be of value to enhance the antitumor activity of TCR-modified T cells in clinical trials.

  17. γδ T Cell-Mediated Immune Responses in Disease and Therapy

    PubMed Central

    Latha, T. Sree; Reddy, Madhava C.; Durbaka, Prasad V. R.; Rachamallu, Aparna; Pallu, Reddanna; Lomada, Dakshayani

    2014-01-01

    The role of γδ T cells in immunotherapy has gained specific importance in the recent years because of their prominent function involving directly or indirectly in the rehabilitation of the diseases. γδ T cells represent a minor population of T cells that express a distinct T cell receptor (TCR) composed of γδ chains instead of αβ chains. Unlike αβ T cells, γδ T cells display a restricted TCR repertoire and recognize mostly unknown non-peptide antigens. γδ T cells act as a link between innate and adaptive immunity, because they lack precise major histocompatibility complex (MHC) restriction and seize the ability to recognize ligands that are generated during affliction. Skin epidermal γδ T cells recognize antigen expressed by damaged or stressed keratinocytes and play an indispensable role in tissue homeostasis and repair through secretion of distinct growth factors. γδ T cell based immunotherapy strategies possess great prominence in the treatment because of the property of their MHC-independent cytotoxicity, copious amount of cytokine release, and a immediate response in infections. Understanding the role of γδ T cells in pathogenic infections, wound healing, autoimmune diseases, and cancer might provide knowledge for the successful treatment of these diseases using γδ T cell based immunotherapy. Enhancing the human Vγ9Vδ2 T cells functions by administration of aminobisphosphonates like zoledronate, pamidronate, and bromohydrin pyrophosphate along with cytokines and monoclonal antibodies shows a hopeful approach for treatment of tumors and infections. The current review summarizes the role of γδ T cells in various human diseases and immunotherapeutic approaches using γδ T cells. PMID:25426120

  18. T cell responses in psoriasis and psoriatic arthritis.

    PubMed

    Diani, Marco; Altomare, Gianfranco; Reali, Eva

    2015-04-01

    According to the current view the histological features of psoriasis arise as a consequence of the interplay between T cells, dendritic cells and keratinocytes giving rise to a self-perpetuating loop that amplifies and sustains inflammation in lesional skin. In particular, myeloid dendritic cell secretion of IL-23 and IL-12 activates IL-17-producing T cells, Th22 and Th1 cells, leading to the production of inflammatory cytokines such as IL-17, IFN-γ, TNF and IL-22. These cytokines mediate effects on keratinocytes thus establishing the inflammatory loop. Unlike psoriasis the immunopathogenic features of psoriatic arthritis are poorly characterized and there is a gap in the knowledge of the pathogenic link between inflammatory T cell responses arising in the skin and the development of joint inflammation. Here we review the knowledge accumulated over the years from the early evidence of autoreactive CD8 T cells that was studied mainly in the years 1990s and 2000s to the recent findings of the role of Th17, Tc17 cells and γδ T cells in psoriatic disease pathogenesis. The review will also focus on common and distinguishing features of T cell responses in psoriatic plaques and in synovial fluid of patients with psoriatic arthritis. The integration of this information could help to distinguish the role played by T cells in the initiation phase of the disease from the role of T cells as downstream effectors sustaining inflammation in psoriatic plaques and potentially leading to disease manifestation in distant joints.

  19. Stepwise B-cell-dependent expansion of T helper clonotypes diversifies the T-cell response

    PubMed Central

    Merkenschlager, Julia; Ploquin, Mickaël J.; Eksmond, Urszula; Andargachew, Rakieb; Thorborn, Georgina; Filby, Andrew; Pepper, Marion; Evavold, Brian; Kassiotis, George

    2016-01-01

    Antigen receptor diversity underpins adaptive immunity by providing the ground for clonal selection of lymphocytes with the appropriate antigen reactivity. Current models attribute T cell clonal selection during the immune response to T-cell receptor (TCR) affinity for either foreign or self peptides. Here, we report that clonal selection of CD4+ T cells is also extrinsically regulated by B cells. In response to viral infection, the antigen-specific TCR repertoire is progressively diversified by staggered clonotypic expansion, according to functional avidity, which correlates with self-reactivity. Clonal expansion of lower-avidity T-cell clonotypes depends on availability of MHC II-expressing B cells, in turn influenced by B-cell activation. B cells clonotypically diversify the CD4+ T-cell response also to vaccination or tumour challenge, revealing a common effect. PMID:26728651

  20. T-cell responses to minor histocompatibility antigens.

    PubMed Central

    Lai, P K; Waterfield, J D; Gascoigne, N R; Sharrock, C E; Mitchison, N A

    1982-01-01

    We have investigated the helper and cytotoxic T-cell response to minor histocompatibility antigens and generated long term antigen-specific cell lines to them. Antigen-specific activity was selected for by regular restimulation with irradiated cells bearing the antigens in the presence of interleukin 2, so that alloreactivity to other cell surface antigens was gradually lost. Helper T cells cultured over several months were active in vivo and in vitro, but the culturing method eventually selected for cytotoxic T cells at the expense of helper T cells, with concomitant changes in the proportions of cells expressing the Lyt phenotypes. Individual long term cultures of cytotoxic T cells specific for minor histocompatibility antigens were restricted by either H2K or D but not both. Helper T cells to minor histocompatibility antigens derived directly from primed F1 mice did not show restriction to the priming parental haplotype. This is consistent with antigen reprocessing by the F1 antigen presenting cells such that populations of helper T cells restricted by both parental H-2 haplotypes were primed. F1 cytotoxic T cells were restricted to the parental H-2 haplotype used for in vitro boosting, irrespective of which H-2 was used for in vivo priming. PMID:6214502

  1. T-cell responses to dengue virus in humans.

    PubMed

    Kurane, Ichiro; Matsutani, Takaji; Suzuki, Ryuji; Takasaki, Tomohiko; Kalayanarooj, Siripen; Green, Sharone; Rothman, Alan L; Ennis, Francis A

    2011-12-01

    Dengue virus (DENV) is a leading cause of morbidity and mortality in most tropical and subtropical areas of the world. Dengue virus infection induces specific CD4+CD8- and CD8+CD4- T cells in humans. In primary infection, T-cell responses to DENV are serotype cross-reactive, but the highest response is to the serotype that caused the infection. The epitopes recognized by DENV-specific T cells are located in most of the structural and non-structural proteins, but NS3 is the protein that is most dominantly recognized. In patients with dengue hemorrhagic fever (DHF) caused by secondary DENV infection, T cells are highly activated in vivo. These highly activated T cells are DENV-specific and oligoclonal. Multiple kinds of lymphokines are produced by the activated T cells, and it has been hypothesized that these lymphokines are responsible for induction of plasma leakage, one of the most characteristic features of DHF. Thus, T-cells play important roles in the pathogenesis of DHF and in the recovery from DENV infection.

  2. T cell Vaccinology: Beyond the Reflection of Infectious Responses

    PubMed Central

    Pennock, Nathan D.; Kedl, Justin D.; Kedl, Ross M.

    2016-01-01

    Inducing sustained, robust CD8+ T cell responses is necessary for therapeutic intervention in chronic infectious diseases and cancer. Unfortunately, most adjuvant formulations fail to induce substantial cellular immunity in humans. Attenuated acute infectious agents induce strong CD8+ T cell immunity, and are thought to therefore represent a good road map for guiding the development of subunit vaccines capable of inducing the same. However, recent evidence suggests that this assumption may need reconsideration. Here we provide an overview of subunit vaccine history as it pertains to instigating T cell responses. We argue that in light of evidence demonstrating that T cell responses to vaccination differ from those induced by infectious challenge, research in pursuit of cellular immunity-inducing vaccine adjuvants should no longer follow only the infection paradigm. PMID:26830540

  3. Improving T cell responses to modified peptides in tumor vaccines.

    PubMed

    Buhrman, Jonathan D; Slansky, Jill E

    2013-03-01

    Immune recognition and elimination of cancerous cells is the primary goal of cancer immunotherapy. However, obstacles including immune tolerance and tumor-induced immunosuppression often limit beneficial immune responses. Vaccination is one proposed intervention that may help to overcome these issues and is an active area of study in cancer immunotherapy. Immunizing with tumor antigenic peptides is a promising, straight-forward vaccine strategy hypothesized to boost preexisting antitumor immunity. However, tumor antigens are often weak T cell agonists, attributable to several mechanisms, including immune self-tolerance and poor immunogenicity of self-derived tumor peptides. One strategy for overcoming these mechanisms is vaccination with mimotopes, or peptide mimics of tumor antigens, which alter the antigen presentation and/or T cell activation to increase the expansion of tumor-specific T cells. Evaluation of mimotope vaccine strategies has revealed that even subtle alterations in peptide sequence can dramatically alter antigen presentation and T cell receptor recognition. Most of this research has been performed using T cell clones, which may not be accurate representations of the naturally occurring antitumor response. The relationship between clones generated after mimotope vaccination and the polyclonal T cell repertoire is unclear. Our work with mimotopes in a mouse model of colon carcinoma has revealed important insights into these issues. We propose that the identification of mimotopes based on stimulation of the naturally responding T cell repertoire will dramatically improve the efficacy of mimotope vaccination.

  4. TIGIT predominantly regulates the immune response via regulatory T cells

    PubMed Central

    Kurtulus, Sema; Sakuishi, Kaori; Ngiow, Shin-Foong; Joller, Nicole; Tan, Dewar J.; Teng, Michele W.L.; Smyth, Mark J.; Kuchroo, Vijay K.; Anderson, Ana C.

    2015-01-01

    Coinhibitory receptors are critical for the maintenance of immune homeostasis. Upregulation of these receptors on effector T cells terminates T cell responses, while their expression on Tregs promotes their suppressor function. Understanding the function of coinhibitory receptors in effector T cells and Tregs is crucial, as therapies that target coinhibitory receptors are currently at the forefront of treatment strategies for cancer and other chronic diseases. T cell Ig and ITIM domain (TIGIT) is a recently identified coinhibitory receptor that is found on the surface of a variety of lymphoid cells, and its role in immune regulation is just beginning to be elucidated. We examined TIGIT-mediated immune regulation in different murine cancer models and determined that TIGIT marks the most dysfunctional subset of CD8+ T cells in tumor tissue as well as tumor-tissue Tregs with a highly active and suppressive phenotype. We demonstrated that TIGIT signaling in Tregs directs their phenotype and that TIGIT primarily suppresses antitumor immunity via Tregs and not CD8+ T cells. Moreover, TIGIT+ Tregs upregulated expression of the coinhibitory receptor TIM-3 in tumor tissue, and TIM-3 and TIGIT synergized to suppress antitumor immune responses. Our findings provide mechanistic insight into how TIGIT regulates immune responses in chronic disease settings. PMID:26413872

  5. TIGIT predominantly regulates the immune response via regulatory T cells.

    PubMed

    Kurtulus, Sema; Sakuishi, Kaori; Ngiow, Shin-Foong; Joller, Nicole; Tan, Dewar J; Teng, Michele W L; Smyth, Mark J; Kuchroo, Vijay K; Anderson, Ana C

    2015-11-02

    Coinhibitory receptors are critical for the maintenance of immune homeostasis. Upregulation of these receptors on effector T cells terminates T cell responses, while their expression on Tregs promotes their suppressor function. Understanding the function of coinhibitory receptors in effector T cells and Tregs is crucial, as therapies that target coinhibitory receptors are currently at the forefront of treatment strategies for cancer and other chronic diseases. T cell Ig and ITIM domain (TIGIT) is a recently identified coinhibitory receptor that is found on the surface of a variety of lymphoid cells, and its role in immune regulation is just beginning to be elucidated. We examined TIGIT-mediated immune regulation in different murine cancer models and determined that TIGIT marks the most dysfunctional subset of CD8+ T cells in tumor tissue as well as tumor-tissue Tregs with a highly active and suppressive phenotype. We demonstrated that TIGIT signaling in Tregs directs their phenotype and that TIGIT primarily suppresses antitumor immunity via Tregs and not CD8+ T cells. Moreover, TIGIT+ Tregs upregulated expression of the coinhibitory receptor TIM-3 in tumor tissue, and TIM-3 and TIGIT synergized to suppress antitumor immune responses. Our findings provide mechanistic insight into how TIGIT regulates immune responses in chronic disease settings.

  6. γδ T cells and the immune response to respiratory syncytial virus infection.

    PubMed

    McGill, Jodi L; Sacco, Randy E

    2016-11-15

    γδ T cells are a subset of nonconventional T cells that play a critical role in bridging the innate and adaptive arms of the immune system. γδ T cells are particularly abundant in ruminant species and may constitute up to 60% of the circulating lymphocyte pool in young cattle. The frequency of circulating γδ T cells is highest in neonatal calves and declines as the animal ages, suggesting these cells may be particularly important in the immune system of the very young. Bovine respiratory syncytial virus (BRSV) is a significant cause of respiratory infection in calves, and is most severe in animals under one year of age. BRSV is also a significant factor in the development of bovine respiratory disease complex (BRDC), the leading cause of morbidity and mortality in feedlot cattle. Human respiratory syncytial virus (RSV) is closely related to BRSV and a leading cause of lower respiratory tract infection in infants and children worldwide. BRSV infection in calves shares striking similarities with RSV infection in human infants. To date, there have been few studies defining the role of γδ T cells in the immune response to BRSV or RSV infection in animals or humans, respectively. However, emerging evidence suggests that γδ T cells may play a critical role in the early recognition of infection and in shaping the development of the adaptive immune response through inflammatory chemokine and cytokine production. Further, while it is clear that γδ T cells accumulate in the lungs during BRSV and RSV infection, their role in protection vs. immunopathology remains unclear. This review will summarize what is currently known about the role of γδ T cells in the immune response to BRSV and BRDC in cattle, and where appropriate, draw parallels to the role of γδ T cells in the human response to RSV infection.

  7. Human influenza viruses and CD8(+) T cell responses.

    PubMed

    Grant, Emma J; Quiñones-Parra, Sergio M; Clemens, E Bridie; Kedzierska, Katherine

    2016-02-01

    Influenza A viruses (IAVs) cause significant morbidity and mortality worldwide, despite new strain-specific vaccines being available annually. As IAV-specific CD8(+) T cells promote viral control in the absence of neutralizing antibodies, and can mediate cross-reactive immunity toward distinct IAVs to drive rapid recovery from both mild and severe influenza disease, there is great interest in developing a universal T cell vaccine. However, despite detailed studies in mouse models of influenza virus infection, there is still a paucity of data on human epitope-specific CD8(+) T cell responses to IAVs. This review focuses on our current understanding of human CD8(+) T cell immunity against distinct IAVs and discusses the possibility of achieving a CD8(+) T cell mediated-vaccine that protects against multiple, distinct IAV strains across diverse human populations. We also review the importance of CD8(+) T cell immunity in individuals highly susceptible to severe influenza infection, including those hospitalised with influenza, the elderly and Indigenous populations.

  8. Itk: The Rheostat of the T Cell Response

    PubMed Central

    Grasis, Juris A.; Tsoukas, Constantine D.

    2011-01-01

    The nonreceptor tyrosine kinase Itk plays a key role in TCR-initiated signaling that directly and significantly affects the regulation of PLCγ1 and the consequent mobilization of Ca2+. Itk also participates in the regulation of cytoskeletal reorganization as well as cellular adhesion, which is necessary for a productive T cell response. The functional cellular outcome of these molecular regulations by Itk renders it an important mediator of T cell development and differentiation. This paper encompasses the structure of Itk, the signaling parameters leading to Itk activation, and Itk effects on molecular pathways resulting in functional cellular outcomes. The incorporation of these factors persuades one to believe that Itk serves as a modulator, or rheostat, critically fine-tuning the T cell response. PMID:21747996

  9. Immune-responsiveness of CD4+ T cells during Streptococcus suis serotype 2 infection

    PubMed Central

    Lecours, Marie-Pier; Letendre, Corinne; Clarke, Damian; Lemire, Paul; Galbas, Tristan; Benoit-Biancamano, Marie-Odile; Thibodeau, Jacques; Gottschalk, Marcelo; Segura, Mariela

    2016-01-01

    The pathogenesis of Streptococcus suis infection, a major swine and human pathogen, is only partially understood and knowledge on the host adaptive immune response is critically scarce. Yet, S. suis virulence factors, particularly its capsular polysaccharide (CPS), enable this bacterium to modulate dendritic cell (DC) functions and potentially impair the immune response. This study aimed to evaluate modulation of T cell activation during S. suis infection and the role of DCs in this response. S. suis-stimulated total mouse splenocytes readily produced TNF-α, IL-6, IFN-γ, CCL3, CXCL9, and IL-10. Ex vivo and in vivo analyses revealed the involvement of CD4+ T cells and a Th1 response. Nevertheless, during S. suis infection, levels of the Th1-derived cytokines TNF-α and IFN-γ were very low. A transient splenic depletion of CD4+ T cells and a poor memory response were also observed. Moreover, CD4+ T cells secreted IL-10 and failed to up-regulate optimal levels of CD40L and CD69 in coculture with DCs. The CPS hampered release of several T cell-derived cytokines in vitro. Finally, a correlation was established between severe clinical signs of S. suis disease and impaired antibody responses. Altogether, these results suggest S. suis interferes with the adaptive immune response. PMID:27905502

  10. Functional adaptation to oxidative stress by memory T cells: an analysis of the role in the cardiovascular disease process.

    PubMed

    Elahi, Maqsood M; Matata, Bashir M

    2008-11-21

    T cells participate in combating infection and critically determine the outcomes in any given disease process. Impaired immune response occurs in a number disease processes such as in cancer and atherosclerosis although the underlying mechanisms are still not fully understood. This article gives an up-to-date review of T cells development and functional adaptation to pathophysiological stimuli and participation in the cardiovascular disease process. In addition, we have discussed the signaling pathways controlled by the microenvironment that determine T cells function and resultant type of immune response. We have also discussed in detail how oxidative stress is a key component of the micro environmental interaction.

  11. Induction of anti-tumor immunity and T-cell responses using nanodelivery systems engrafting TLR-5 ligand.

    PubMed

    Panda, Amulya K

    2011-02-01

    Induction of activated T-cell responses is a prerequisite for the development of vaccine against intracellular infection and for the control of cancer. Particulate nanoscale delivery systems deliver antigens intracellularly and help in inducing T-cell responses. T-cell responses can be further augmented by targeting these particles to dendritic cells, which have the ability to induce both innate and adaptive immune responses. Flagellin, which acts as a TLR-5 ligand, has been extensively explored for its adjuvant activity. The paper under evaluation reports a novel vaccine delivery platform technology for induction of a T-cell response using a nanoscale liposome containing antigen and a small synthetic peptide representing TLR-5-binding motifs of flagellin. Vaccination using this nanodelivery system activated dendritic cells through TLR-5 activation and induced both innate and adaptive immune responses. Such novel delivery systems can improve modern vaccine formulation, particularly for the generation of activated T-cell responses and anti-tumor immunity.

  12. Success and failure of virus-specific T cell responses in hepatitis C virus infection.

    PubMed

    Neumann-Haefelin, Christoph; Thimme, Robert

    2011-01-01

    Hepatitis C virus (HCV) infection is only cleared in a minority of infected individuals, the majority of patients develop chronic infection. Chronic HCV infection potentially leads to liver fibrosis, cirrhosis and finally hepatocellular carcinoma. The host immune response is an important determinant in the outcome of HCV infection. Innate as well as adaptive cellular and humoral immune responses mediate important antiviral actions; however, virus-specific T cell responses appear to be most critical. Indeed, strong and multispecific CD4+ as well as CD8+ T cell responses are required for viral clearance. Interestingly, individuals who express certain HLA alleles (which are important for antigen presentation to CD4+ and CD8+ T cells) have a higher chance to clear the virus. The mechanisms of protection by HLA class I alleles such as HLA-B27 have been characterized recently. In most individuals, however, the HCV-specific immune response fails to clear the virus. Several mechanisms underlying this HCV-specific T cell failure have been identified. These include viral factors such as viral escape mutations and immunological factors such as the expression of inhibitory receptors, which lead to CD8+ T cell dysfunction. An in-depth understanding of the determinants of success or failure of the HCV-specific T cell response is critical for the development of prophylactic as well as therapeutic vaccination regimes against HCV. Here, we will discuss the virological and immunological determinants of HCV clearance and persistence.

  13. Innate lymphoid cells regulate CD4+ T-cell responses to intestinal commensal bacteria.

    PubMed

    Hepworth, Matthew R; Monticelli, Laurel A; Fung, Thomas C; Ziegler, Carly G K; Grunberg, Stephanie; Sinha, Rohini; Mantegazza, Adriana R; Ma, Hak-Ling; Crawford, Alison; Angelosanto, Jill M; Wherry, E John; Koni, Pandelakis A; Bushman, Frederic D; Elson, Charles O; Eberl, Gérard; Artis, David; Sonnenberg, Gregory F

    2013-06-06

    Innate lymphoid cells (ILCs) are a recently characterized family of immune cells that have critical roles in cytokine-mediated regulation of intestinal epithelial cell barrier integrity. Alterations in ILC responses are associated with multiple chronic human diseases, including inflammatory bowel disease, implicating a role for ILCs in disease pathogenesis. Owing to an inability to target ILCs selectively, experimental studies assessing ILC function have predominantly used mice lacking adaptive immune cells. However, in lymphocyte-sufficient hosts ILCs are vastly outnumbered by CD4(+) T cells, which express similar profiles of effector cytokines. Therefore, the function of ILCs in the presence of adaptive immunity and their potential to influence adaptive immune cell responses remain unknown. To test this, we used genetic or antibody-mediated depletion strategies to target murine ILCs in the presence of an adaptive immune system. We show that loss of retinoic-acid-receptor-related orphan receptor-γt-positive (RORγt(+)) ILCs was associated with dysregulated adaptive immune cell responses against commensal bacteria and low-grade systemic inflammation. Remarkably, ILC-mediated regulation of adaptive immune cells occurred independently of interleukin (IL)-17A, IL-22 or IL-23. Genome-wide transcriptional profiling and functional analyses revealed that RORγt(+) ILCs express major histocompatibility complex class II (MHCII) and can process and present antigen. However, rather than inducing T-cell proliferation, ILCs acted to limit commensal bacteria-specific CD4(+) T-cell responses. Consistent with this, selective deletion of MHCII in murine RORγt(+) ILCs resulted in dysregulated commensal bacteria-dependent CD4(+) T-cell responses that promoted spontaneous intestinal inflammation. These data identify that ILCs maintain intestinal homeostasis through MHCII-dependent interactions with CD4(+) T cells that limit pathological adaptive immune cell responses to commensal

  14. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    SciTech Connect

    Doi, Keiko; Fujimoto, Takahiro; Okamura, Tadashi; Ogawa, Masahiro; Tanaka, Yoko; Mototani, Yasumasa; Goto, Motohito; Ota, Takeharu; Matsuzaki, Hiroshi; Kuroki, Masahide; Tsunoda, Toshiyuki; Sasazuki, Takehiko; Shirasawa, Senji

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. Black-Right-Pointing-Pointer Zfat-deficiency leads to reduction in the number of the peripheral T cells. Black-Right-Pointing-Pointer Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Decreased expression of IL-7R{alpha}, IL-2R{alpha} and IL-2 in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7R{alpha} and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2R{alpha} expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

  15. Insights into the Relationship between Toll Like Receptors and Gamma Delta T Cell Responses

    PubMed Central

    Dar, Asif Amin; Patil, Rushikesh Sudam; Chiplunkar, Shubhada Vivek

    2014-01-01

    The tumor microenvironment is an important aspect of cancer biology that contributes to tumor initiation, tumor progression and responses to therapy. The composition and characteristics of the tumor microenvironment vary widely and are important in determining the anti-tumor immune response. Successful immunization requires activation of both innate and adaptive immunity. Generally, immune system is compromised in patients with cancer due to immune suppression, loss of tumor antigen expression and dysfunction of antigen presenting cells (APC). Thus, therapeutic immunization leading to cancer regression remains a significant challenge. Certain cells of the immune system, including dendritic cells (DCs) and gamma delta (γδ) T cells are capable of driving potent anti-tumor responses. The property of MHC-unrestricted cytotoxicity, high potential of cytokine release, tissue tropism and early activation in infections and malignant disease makes γδ T cells as an emerging candidate for immunotherapy. Various strategies are being developed to enhance anti-tumor immune responses of γδ T cells and DCs one of them is the use of novel adjuvants like toll like receptors (TLR) agonists, which enhance γδ T cell function directly or through DC activation, which has ability to prime γδ T cells. TLR agonists are being used clinically either alone or in combination with tumor antigens and has shown initial success in both enhancing immune responses and eliciting anti-tumor activity. TLR activated γδ T cells and DCs nurture each other’s activation. This provides a potent base for first line of defense and manipulation of the adaptive response against pathogens and cancer. The available data provides a strong rationale for initiating combinatorial therapy for the treatment of diseases and this review will summarize the application of adjuvants (TLRs) for boosting immune response of γδ T cells to treat cancer and infectious diseases and their use in combinatorial therapy

  16. Contribution of herpesvirus specific CD8 T cells to anti-viral T cell response in humans.

    PubMed

    Sandalova, Elena; Laccabue, Diletta; Boni, Carolina; Tan, Anthony T; Fink, Katja; Ooi, Eng Eong; Chua, Robert; Shafaeddin Schreve, Bahar; Ferrari, Carlo; Bertoletti, Antonio

    2010-08-19

    Herpesviruses infect most humans. Their infections can be associated with pathological conditions and significant changes in T cell repertoire but evidences of symbiotic effects of herpesvirus latency have never been demonstrated. We tested the hypothesis that HCMV and EBV-specific CD8 T cells contribute to the heterologous anti-viral immune response. Volume of activated/proliferating virus-specific and total CD8 T cells was evaluated in 50 patients with acute viral infections: 20 with HBV, 12 with Dengue, 12 with Influenza, 3 with Adenovirus infection and 3 with fevers of unknown etiology. Virus-specific (EBV, HCMV, Influenza) pentamer+ and total CD8 T cells were analyzed for activation (CD38/HLA-DR), proliferation (Ki-67/Bcl-2(low)) and cytokine production. We observed that all acute viral infections trigger an expansion of activated/proliferating CD8 T cells, which differs in size depending on the infection but is invariably inflated by CD8 T cells specific for persistent herpesviruses (HCMV/EBV). CD8 T cells specific for other non-related non persistent viral infection (i.e. Influenza) were not activated. IL-15, which is produced during acute viral infections, is the likely contributing mechanism driving the selective activation of herpesvirus specific CD8 T cells. In addition we were able to show that herpesvirus specific CD8 T cells displayed an increased ability to produce the anti-viral cytokine interferon-gamma during the acute phase of heterologous viral infection. Taken together, these data demonstrated that activated herpesvirus specific CD8 T cells inflate the activated/proliferating CD8 T cells population present during acute viral infections in human and can contribute to the heterologous anti-viral T cell response.

  17. Mitochondrial respiration controls lysosomal function during inflammatory T cell responses

    PubMed Central

    Baixauli, Francesc; Acín-Pérez, Rebeca; Villarroya-Beltrí, Carolina; Mazzeo, Carla; Nuñez-Andrade, Norman; Gabandé-Rodriguez, Enrique; Dolores Ledesma, Maria; Blázquez, Alberto; Martin, Miguel Angel; Falcón-Pérez, Juan Manuel; Redondo, Juan Miguel; Enríquez, Jose Antonio; Mittelbrunn, Maria

    2016-01-01

    Summary The endolysosomal system is critical for the maintenance of cellular homeostasis. However, how endolysosomal compartment is regulated by mitochondrial function is largely unknown. We have generated a mouse model with defective mitochondrial function in CD4+ T lymphocytes by genetic deletion of the mitochondrial transcription factor A (Tfam). Mitochondrial respiration-deficiency impairs lysosome function, promotes p62 and sphingomyelin accumulation and disrupts endolysosomal trafficking pathways and autophagy, thus linking a primary mitochondrial dysfunction to a lysosomal storage disorder. The impaired lysosome function in Tfam-deficient cells subverts T cell differentiation toward pro-inflammatory subsets and exacerbates the in vivo inflammatory response. Restoration of NAD+ levels improves lysosome function and corrects the inflammatory defects in Tfam-deficient T cells. Our results uncover a mechanism by which mitochondria regulate lysosome function to preserve T cell differentiation and effector functions, and identify novel strategies for intervention in mitochondrial-related diseases. PMID:26299452

  18. Mitochondrial Respiration Controls Lysosomal Function during Inflammatory T Cell Responses.

    PubMed

    Baixauli, Francesc; Acín-Pérez, Rebeca; Villarroya-Beltrí, Carolina; Mazzeo, Carla; Nuñez-Andrade, Norman; Gabandé-Rodriguez, Enrique; Ledesma, Maria Dolores; Blázquez, Alberto; Martin, Miguel Angel; Falcón-Pérez, Juan Manuel; Redondo, Juan Miguel; Enríquez, Jose Antonio; Mittelbrunn, Maria

    2015-09-01

    The endolysosomal system is critical for the maintenance of cellular homeostasis. However, how endolysosomal compartment is regulated by mitochondrial function is largely unknown. We have generated a mouse model with defective mitochondrial function in CD4(+) T lymphocytes by genetic deletion of the mitochondrial transcription factor A (Tfam). Mitochondrial respiration deficiency impairs lysosome function, promotes p62 and sphingomyelin accumulation, and disrupts endolysosomal trafficking pathways and autophagy, thus linking a primary mitochondrial dysfunction to a lysosomal storage disorder. The impaired lysosome function in Tfam-deficient cells subverts T cell differentiation toward proinflammatory subsets and exacerbates the in vivo inflammatory response. Restoration of NAD(+) levels improves lysosome function and corrects the inflammatory defects in Tfam-deficient T cells. Our results uncover a mechanism by which mitochondria regulate lysosome function to preserve T cell differentiation and effector functions, and identify strategies for intervention in mitochondrial-related diseases.

  19. Understanding the T cell immune response in SARS coronavirus infection.

    PubMed

    Janice Oh, Hsueh-Ling; Ken-En Gan, Samuel; Bertoletti, Antonio; Tan, Yee-Joo

    2012-09-01

    The severe acute respiratory syndrome (SARS) epidemic started in late 2002 and swiftly spread across 5 continents with a mortality rate of around 10%. Although the epidemic was eventually controlled through the implementation of strict quarantine measures, there continues a need to investigate the SARS coronavirus (SARS-CoV) and develop interventions should it re-emerge. Numerous studies have shown that neutralizing antibodies against the virus can be found in patients infected with SARS-CoV within days upon the onset of illness and lasting up to several months. In contrast, there is little data on the kinetics of T cell responses during SARS-CoV infection and little is known about their role in the recovery process. However, recent studies in mice suggest the importance of T cells in viral clearance during SARS-CoV infection. Moreover, a growing number of studies have investigated the memory T cell responses in recovered SARS patients. This review covers the available literature on the emerging importance of T cell responses in SARS-CoV infection, particularly on the mapping of cytotoxic T lymphocyte (CTL) epitopes, longevity, polyfunctionality and human leukocyte antigen (HLA) association as well as their potential implications on treatment and vaccine development.

  20. SAG/Rbx2-Dependent Neddylation Regulates T-Cell Responses.

    PubMed

    Mathewson, Nathan D; Fujiwara, Hideaki; Wu, Shin-Rong; Toubai, Tomomi; Oravecz-Wilson, Katherine; Sun, Yaping; Rossi, Corinne; Zajac, Cynthia; Sun, Yi; Reddy, Pavan

    2016-10-01

    Neddylation is a crucial post-translational modification that depends on the E3 cullin ring ligase (CRL). The E2-adapter component of the CRL, sensitive to apoptosis gene (SAG), is critical for the function of CRL-mediated ubiquitination; thus, the deletion of SAG regulates neddylation. We examined the role of SAG-dependent neddylation in T-cell-mediated immunity using multiple approaches: a novel T-cell-specific, SAG genetic knockout (KO) and chemical inhibition with small-molecule MLN4924. The KO animals were viable and showed phenotypically normal mature T-cell development. However, in vitro stimulation of KO T cells revealed significantly decreased activation, proliferation, and T-effector cytokine release, compared with WT. Using in vivo clinically relevant models of allogeneic bone marrow transplantation also demonstrated reduced proliferation and effector cytokine secretion associated with markedly reduced graft-versus-host disease. Similar in vitro and in vivo results were observed with the small-molecule inhibitor of neddylation, MLN4924. Mechanistic studies demonstrated that SAG-mediated effects in T cells were concomitant with an increase in suppressor of cytokine signaling, but not NF-κB translocation. Our studies suggest that SAG is a novel molecular target that regulates T-cell responses and that inhibiting neddylation with the clinically available small-molecule MLN4924 may represent a novel strategy to mitigate T-cell-mediated immunopathologies, such as graft-versus-host disease.

  1. CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection

    PubMed Central

    Cvrljevic, Anna; Khan, Mohd Moin; Treise, Irina; Adler, Thure; Aguilar-Pimentel, Juan Antonio; Au-Yeung, Byron; Sittig, Eleonora; Laajala, Teemu Daniel; Chen, Yiling; Oeder, Sebastian; Calzada-Wack, Julia; Horsch, Marion; Aittokallio, Tero; Busch, Dirk H.; Ollert, Markus W.; Neff, Frauke; Beckers, Johannes; Gailus-Durner, Valerie; Fuchs, Helmut; de Angelis, Martin Hrabě; Chen, Zhi; Lahesmaa, Riitta; Westermarck, Jukka

    2016-01-01

    The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ) present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell activation during adaptive immune response. These results also reveal CIP2AHOZ as a possible novel mouse model for studying the role of PP2A activity in immune regulation. On the other hand, the results also indicate that CIP2A targeting cancer therapies would not cause serious immunological side-effects. PMID:27100879

  2. Human T cell responses to Japanese encephalitis virus in health and disease.

    PubMed

    Turtle, Lance; Bali, Tanushka; Buxton, Gemma; Chib, Savita; Chan, Sajesh; Soni, Mohammed; Hussain, Mohammed; Isenman, Heather; Fadnis, Prachi; Venkataswamy, Manjunatha M; Satishkumar, Vishali; Lewthwaite, Penny; Kurioka, Ayako; Krishna, Srinivasa; Shankar, M Veera; Ahmed, Riyaz; Begum, Ashia; Ravi, Vasanthapuram; Desai, Anita; Yoksan, Sutee; Fernandez, Stefan; Willberg, Christian B; Kloverpris, Henrik N; Conlon, Christopher; Klenerman, Paul; Satchidanandam, Vijaya; Solomon, Tom

    2016-06-27

    Japanese encephalitis (JE) virus (JEV) is an important cause of encephalitis in children of South and Southeast Asia. However, the majority of individuals exposed to JEV only develop mild symptoms associated with long-lasting adaptive immunity. The related flavivirus dengue virus (DENV) cocirculates in many JEV-endemic areas, and clinical data suggest cross-protection between DENV and JEV. To address the role of T cell responses in protection against JEV, we conducted the first full-breadth analysis of the human memory T cell response using a synthetic peptide library. Ex vivo interferon-γ (IFN-γ) responses to JEV in healthy JEV-exposed donors were mostly CD8(+) and targeted nonstructural (NS) proteins, whereas IFN-γ responses in recovered JE patients were mostly CD4(+) and targeted structural proteins and the secreted protein NS1. Among patients, a high quality, polyfunctional CD4(+) T cell response was associated with complete recovery from JE. T cell responses from healthy donors showed a high degree of cross-reactivity to DENV that was less apparent in recovered JE patients despite equal exposure. These data reveal divergent functional CD4(+) and CD8(+) T cell responses linked to different clinical outcomes of JEV infection, associated with distinct targeting and broad flavivirus cross-reactivity including epitopes from DENV, West Nile, and Zika virus.

  3. Human T cell responses to Japanese encephalitis virus in health and disease

    PubMed Central

    Bali, Tanushka; Buxton, Gemma; Chib, Savita; Chan, Sajesh; Soni, Mohammed; Hussain, Mohammed; Isenman, Heather; Fadnis, Prachi; Venkataswamy, Manjunatha M.; Satishkumar, Vishali; Lewthwaite, Penny; Kurioka, Ayako; Krishna, Srinivasa; Shankar, M. Veera; Ahmed, Riyaz; Begum, Ashia; Ravi, Vasanthapuram; Desai, Anita; Yoksan, Sutee; Fernandez, Stefan; Willberg, Christian B.; Kloverpris, Henrik N.; Conlon, Christopher; Satchidanandam, Vijaya; Solomon, Tom

    2016-01-01

    Japanese encephalitis (JE) virus (JEV) is an important cause of encephalitis in children of South and Southeast Asia. However, the majority of individuals exposed to JEV only develop mild symptoms associated with long-lasting adaptive immunity. The related flavivirus dengue virus (DENV) cocirculates in many JEV-endemic areas, and clinical data suggest cross-protection between DENV and JEV. To address the role of T cell responses in protection against JEV, we conducted the first full-breadth analysis of the human memory T cell response using a synthetic peptide library. Ex vivo interferon-γ (IFN-γ) responses to JEV in healthy JEV-exposed donors were mostly CD8+ and targeted nonstructural (NS) proteins, whereas IFN-γ responses in recovered JE patients were mostly CD4+ and targeted structural proteins and the secreted protein NS1. Among patients, a high quality, polyfunctional CD4+ T cell response was associated with complete recovery from JE. T cell responses from healthy donors showed a high degree of cross-reactivity to DENV that was less apparent in recovered JE patients despite equal exposure. These data reveal divergent functional CD4+ and CD8+ T cell responses linked to different clinical outcomes of JEV infection, associated with distinct targeting and broad flavivirus cross-reactivity including epitopes from DENV, West Nile, and Zika virus. PMID:27242166

  4. Modulation of T cell response by Phellinus linteus.

    PubMed

    Lin, Chun-Jung; Lien, Hsiu-Man; Lin, Hwai-Jeng; Huang, Chao-Lu; Kao, Min-Chuan; Chen, Yu-An; Wang, Chien-Kuo; Chang, Hsiao-Yun; Chang, Yin-Kuang; Wu, Hua-Shan; Lai, Chih-Ho

    2016-01-01

    Phellinus linteus, a species of mushroom, has been shown to contribute to health benefits, such as anti-inflammatory activity and immunomodulatory efficacy. The aim of this study was to analyze the most effective constituents of P. linteus fermented broths, polysaccharides, and to evaluate their immunoregulatory effects on T cells. Four fermented broths (PL1-4) and the dialyzate medium (MD) were prepared from P. linteus mycelia, and the polysaccharide contents of each were analyzed. The P. linteus samples were tested for biological activity in the regulation of T cell activation. In T cells, the production of mitogen-induced interleukin (IL)-2 and cell cycle progression were dose-responsively inhibited by PL3 and MD, primarily through cell-cycle arrest in S phase. PL3 broth, which contained large quantities of polysaccharides, significantly decreased the ratio of interferon-gamma (IFN-γ) to interleukin 4 (IL-4) in T cells. Thus, P. linteus fermented broths produced additive effects on the regulation of the Th1/Th2 balance and show promise for the development of immunomodulatory therapeutics.

  5. Adaptive Memory of Human NK-like CD8(+) T-Cells to Aging, and Viral and Tumor Antigens.

    PubMed

    Pita-López, María Luisa; Pera, Alejandra; Solana, Rafael

    2016-01-01

    Human natural killer (NK)-like CD8(+) T-cells are singular T-cells that express both T and NK cell markers such as CD56; their frequencies depend on their differentiation and activation during their lifetime. There is evidence of the presence of these innate CD8(+) T-cells in the human umbilical cord, highlighting the necessity of investigating whether the NK-like CD8(+) T-cells arise in the early stages of life (gestation). Based on the presence of cell surface markers, these cells have also been referred to as CD8(+)KIR(+) T-cells, innate CD8(+) T-cells, CD8(+)CD28(-)KIR(+) T-cells or NKT-like CD8(+)CD56(+) cells. However, the functional and co-signaling significance of these NK cell receptors on NK-like CD8(+) T-cells is less clear. Also, the diverse array of costimulatory and co-inhibitory receptors are spatially and temporally regulated and may have distinct overlapping functions on NK-like CD8(+) T-cell priming, activation, differentiation, and memory responses associated with different cell phenotypes. Currently, there is no consensus regarding the functional properties and phenotypic characterization of human NK-like CD8(+) T-cells. Environmental factors, such as aging, autoimmunity, inflammation, viral antigen re-exposure, or the presence of persistent tumor antigens have been shown to allow differentiation ("adaptation") of the NK-like CD8(+) T-cells; the elucidation of this differentiation process and a greater understanding of the characteristics of these cells could be important for their eventual in potential therapeutic applications aimed at improving protective immunity. This review will attempt to elucidate an understanding of the characteristics of these cells with the goal toward their eventual use in potential therapeutic applications aimed at improving protective immunity.

  6. Positive and negative regulation of T cell responses by fibroblastic reticular cells within paracortical regions of lymph nodes

    PubMed Central

    Siegert, Stefanie; Luther, Sanjiv A.

    2012-01-01

    Fibroblastic reticular cells (FRC) form the structural backbone of the T cell rich zones in secondary lymphoid organs (SLO), but also actively influence the adaptive immune response. They provide a guidance path for immigrating T lymphocytes and dendritic cells (DC) and are the main local source of the cytokines CCL19, CCL21, and IL-7, all of which are thought to positively regulate T cell homeostasis and T cell interactions with DC. Recently, FRC in lymph nodes (LN) were also described to negatively regulate T cell responses in two distinct ways. During homeostasis they express and present a range of peripheral tissue antigens, thereby participating in peripheral tolerance induction of self-reactive CD8+ T cells. During acute inflammation T cells responding to foreign antigens presented on DC very quickly release pro-inflammatory cytokines such as interferon γ. These cytokines are sensed by FRC which transiently produce nitric oxide (NO) gas dampening the proliferation of neighboring T cells in a non-cognate fashion. In summary, we propose a model in which FRC engage in a bidirectional crosstalk with both DC and T cells to increase the efficiency of the T cell response. However, during an acute response, FRC limit excessive expansion and inflammatory activity of antigen-specific T cells. This negative feedback loop may help to maintain tissue integrity and function during rapid organ growth. PMID:22973278

  7. Tumor-infiltrating regulatory T cells inhibit endogenous cytotoxic T cell responses to lung adenocarcinoma

    PubMed Central

    Ganesan, Anusha-Preethi; Johansson, Magnus; Ruffell, Brian; Beltran, Adam; Lau, Jonathan; Jablons, David M.; Coussens, Lisa M.

    2013-01-01

    Immune cells comprise a substantial proportion of the tumor mass in human non-small cell lung cancers (NSCLC), but the precise composition and significance of this infiltration is unclear. Herein we examined immune complexity of human NSCLC as well as NSCLC developing in CC10-TAg transgenic mice, and revealed that CD4+ T lymphocytes represent the dominant population of CD45+ immune cells, and relative to normal lung tissue, CD4+FoxP3+ regulatory T cells (Tregs) were significantly increased as a proportion of total CD4+ cells. To assess the functional significance of increased Treg cells, we evaluated CD8+ T cell-deficient/CC10-TAg mice and revealed that CD8+ T cells significantly controlled tumor growth with anti-tumor activity that was partially repressed by Treg cells. However, while treatment with anti-CD25 depleting mAb as monotherapy preferentially depleted Tregs and improved CD8+ T cell-mediated control of tumor progression during early tumor development, similar monotherapy was ineffective at later stages. Since mice bearing early NSCLC treated with anti-CD25 mAb exhibited increased tumor cell death associated with infiltration by CD8+ T cells expressing elevated levels of granzyme A, granzyme B, perforin and interferon-γ, we therefore evaluated carboplatin combination therapy resulting in a significantly extended survival beyond that observed with chemotherapy alone, indicating that Treg depletion in combination with cytotoxic therapy may be beneficial as a treatment strategy for advanced NSCLC. PMID:23851682

  8. Myd88 Initiates Early Innate Immune Responses and Promotes CD4 T Cells during Coronavirus Encephalomyelitis

    PubMed Central

    Butchi, Niranjan; Kapil, Parul; Puntambekar, Shweta; Stohlman, Stephen A.; Hinton, David R.

    2015-01-01

    ABSTRACT Myd88 signaling is critical to the control of numerous central nervous system (CNS) infections by promoting both innate and adaptive immune responses. Nevertheless, the extent to which Myd88 regulates type I interferon (IFN) versus proinflammatory factors and T cell function, as well as the anatomical site of action, varies extensively with the pathogen. CNS infection by neurotropic coronavirus with replication confined to the brain and spinal cord induces protective IFN-α/β via Myd88-independent activation of melanoma differentiation-associated gene 5 (MDA5). However, a contribution of Myd88-dependent signals to CNS pathogenesis has not been assessed. Infected Myd88−/− mice failed to control virus, exhibited enhanced clinical disease coincident with increased demyelination, and succumbed to infection within 3 weeks. The induction of IFN-α/β, as well as of proinflammatory cytokines and chemokines, was impaired early during infection. However, defects in both IFN-α/β and select proinflammatory factors were rapidly overcome prior to T cell recruitment. Myd88 deficiency also specifically blunted myeloid and CD4 T cell recruitment into the CNS without affecting CD8 T cells. Moreover, CD4 T cells but not CD8 T cells were impaired in IFN-γ production. Ineffective virus control indeed correlated most prominently with reduced antiviral IFN-γ in the CNS of Myd88−/− mice. The results demonstrate a crucial role for Myd88 both in early induction of innate immune responses during coronavirus-induced encephalomyelitis and in specifically promoting protective CD4 T cell activation. In the absence of these responses, functional CD8 T cells are insufficient to control viral spread within the CNS, resulting in severe demyelination. IMPORTANCE During central nervous system (CNS) infections, signaling through the adaptor protein Myd88 promotes both innate and adaptive immune responses. The extent to which Myd88 regulates antiviral type I IFN, proinflammatory

  9. Dengue virus specific dual HLA binding T cell epitopes induce CD8+ T cell responses in seropositive individuals

    PubMed Central

    Comber, Joseph D; Karabudak, Aykan; Huang, Xiaofang; Piazza, Paolo A; Marques, Ernesto T A; Philip, Ramila

    2015-01-01

    Dengue virus infects an estimated 300 million people each year and even more are at risk of becoming infected as the virus continues to spread into new areas. Despite the increase in viral prevalence, no anti-viral medications or vaccines are approved for treating or preventing infection. CD8+ T cell responses play a major role in viral clearance. Therefore, effective vaccines that induce a broad, multi-functional T cell response with substantial cross-reactivity between all virus serotypes can have major impacts on reducing infection rates and infection related complications. Here, we took an immunoproteomic approach to identify novel MHC class I restricted T cell epitopes presented by dengue virus infected cells, representing the natural and authentic targets of the T cell response. Using this approach we identified 4 novel MHC-I restricted epitopes: 2 with the binding motif for HLA-A24 molecules and 2 with both HLA-A2 and HLA-A24 binding motifs. These peptides were able to activate CD8+ T cell responses in both healthy, seronegative individuals and in seropositive individuals who have previously been infected with dengue virus. Importantly, the dual binding epitopes activated pre-existing T cell precursors in PBMCs obtained from both HLA-A2+ and HLA-A24+ seropositive individuals. Together, the data indicate that these epitopes are immunologically relevant T cell activating peptides presented on infected cells during a natural infection and therefore may serve as candidate antigens for the development of effective multi-serotype specific dengue virus vaccines. PMID:25668665

  10. Dengue virus specific dual HLA binding T cell epitopes induce CD8+ T cell responses in seropositive individuals.

    PubMed

    Comber, Joseph D; Karabudak, Aykan; Huang, Xiaofang; Piazza, Paolo A; Marques, Ernesto T A; Philip, Ramila

    2014-01-01

    Dengue virus infects an estimated 300 million people each year and even more are at risk of becoming infected as the virus continues to spread into new areas. Despite the increase in viral prevalence, no anti-viral medications or vaccines are approved for treating or preventing infection. CD8+ T cell responses play a major role in viral clearance. Therefore, effective vaccines that induce a broad, multi-functional T cell response with substantial cross-reactivity between all virus serotypes can have major impacts on reducing infection rates and infection related complications. Here, we took an immunoproteomic approach to identify novel MHC class I restricted T cell epitopes presented by dengue virus infected cells, representing the natural and authentic targets of the T cell response. Using this approach we identified 4 novel MHC-I restricted epitopes: 2 with the binding motif for HLA-A24 molecules and 2 with both HLA-A2 and HLA-A24 binding motifs. These peptides were able to activate CD8+ T cell responses in both healthy, seronegative individuals and in seropositive individuals who have previously been infected with dengue virus. Importantly, the dual binding epitopes activated pre-existing T cell precursors in PBMCs obtained from both HLA-A2+ and HLA-A24+ seropositive individuals. Together, the data indicate that these epitopes are immunologically relevant T cell activating peptides presented on infected cells during a natural infection and therefore may serve as candidate antigens for the development of effective multi-serotype specific dengue virus vaccines.

  11. T cell responses induced by allergen-specific immunotherapy

    PubMed Central

    Maggi, E

    2010-01-01

    Allergen-specific immunotherapy is recognized as a highly effective practice in the treatment of patients with severe allergic rhinitis and/or asthma and is recommended by World Health Organization as an integrated part of allergy management strategy. Several studies have shown that allergen-specific immunotherapy, based on the administration of increasing doses of allergen, achieves a hyposensitization and reduces both early and late responses occurring during the natural exposure to the allergen itself. This is the unique antigen-specific immunomodulatory treatment in current use for human diseases. Successful immunotherapy is associated with reductions in symptoms and medication scores and improved quality of life. After interruption it usually confers long-term remission of symptoms and prevents the onset of new sensitizations in children up to a number of years. Subcutaneous immunotherapy usually suppresses the allergen-induced late response in target organs, likely due to the reduction of the infiltration of T cells, eosinophils, basophils, mast cells and neutrophils. In addition to the reduction of cells of allergic inflammation, immunotherapy also decreases inflammatory mediators at the site of allergen exposure. This review provides an update on the immunological T cell responses induced by conventional subcutaneous and sublingual immunotherapy, and gives a unifying view to reconciling the old dualism between immunoredirecting and immunoregulating mechanisms. PMID:20408857

  12. Hemolysin-producing Listeria monocytogenes affects the immune response to T-cell-dependent and T-cell-independent antigens.

    PubMed Central

    Hage-Chahine, C M; Del Giudice, G; Lambert, P H; Pechere, J C

    1992-01-01

    A murine experimental infection with a hemolysin-producing (Hly+) strain of Listeria monocytogenes and a non-hemolysin-producing (Hly-) mutant was used as an in vivo model to evaluate the role of hemolysin production in the immune response. No antilisterial antibodies were detectable following sublethal infection with Hly+ bacteria, but consistent antilisterial immunoglobulin G (IgG) and IgM antibody production was observed following sublethal infection with the Hly- mutant. Hly+ but not Hly- L. monocytogenes induced transient inhibition of antibody response to Hly- bacteria and to unrelated T-cell-dependent (tetanus toxoid) and T-cell-independent (pneumococcal polysaccharide 3) antigens. Transient inhibition of the activation of an antigen-specific T-cell clone was also observed following Hly+ infection of antigen-presenting cells but not following Hly- infection. These results suggest that hemolysin production by L. monocytogenes is an important factor in modulating the immune response to T-cell-dependent and T-cell-independent antigens in infected individuals. Images PMID:1548067

  13. CD1-Restricted T Cells at the Crossroad of Innate and Adaptive Immunity

    PubMed Central

    Pereira, Catia S.

    2016-01-01

    Lipid-specific T cells comprise a group of T cells that recognize lipids bound to the MHC class I-like CD1 molecules. There are four isoforms of CD1 that are expressed at the surface of antigen presenting cells and therefore capable of presenting lipid antigens: CD1a, CD1b, CD1c, and CD1d. Each one of these isoforms has distinct structural features and cellular localizations, which promotes binding to a broad range of different types of lipids. Lipid antigens originate from either self-tissues or foreign sources, such as bacteria, fungus, or plants and their recognition by CD1-restricted T cells has important implications in infection but also in cancer and autoimmunity. In this review, we describe the characteristics of CD1 molecules and CD1-restricted lipid-specific T cells, highlighting the innate-like and adaptive-like features of different CD1-restricted T cell subtypes. PMID:28070524

  14. OX40+ regulatory T cells in cutaneous squamous cell carcinoma suppress effector T cell responses and associate with metastatic potential

    PubMed Central

    Lai, Chester; August, Suzannah; Albibas, Amel; Behar, Ramnik; Cho, Shin-Young; Polak, Marta E; Theaker, Jeff; MacLeod, Amanda S; French, Ruth R; Glennie, Martin J; Al-Shamkhani, Aymen; Healy, Eugene

    2016-01-01

    Purpose Cutaneous squamous cell carcinoma (cSCC) is the most common human cancer with metastatic potential. Despite T cells accumulating around cSCCs, these tumors continue to grow and persist. To investigate reasons for failure of T cells to mount a protective response in cSCC, we focused on regulatory T cells (Tregs) as this suppressive population is well represented among the infiltrating lymphocytes. Experimental Design Flow cytometry was conducted on cSCC lymphocytes and in vitro functional assays were performed using sorted tumoral T cells. Lymphocyte subsets in primary cSCCs were quantified immunohistochemically. Results FOXP3+ Tregs were more frequent in cSCCs than in peripheral blood (p<0.0001, n=86 tumors). Tumoral Tregs suppressed proliferation of tumoral effector CD4+ (p=0.005, n=10 tumors) and CD8+ T cells (p=0.043, n=9 tumors) and inhibited interferon-γ secretion by tumoral effector T cells (p=0.0186, n=11 tumors). The costimulatory molecule OX40 was expressed predominantly on tumoral Tregs (p<0.0001, n=15 tumors) and triggering OX40 with an agonist anti-OX40 antibody overcame the suppression exerted by Tregs, leading to increased tumoral effector CD4+ lymphocyte proliferation (p=0.0098, n=10 tumors). Tregs and OX40+ lymphocytes were more abundant in primary cSCCs which metastasized than in primary cSCCs which had not metastasized (n=48 and n=49 tumors respectively). Conclusions Tregs in cSCCs suppress effector T cell responses and are associated with subsequent metastasis, suggesting a key role for Tregs in cSCC development and progression. OX40 agonism reversed the suppressive effects of Tregs in vitro, suggesting that targeting OX40 could benefit the subset of cSCC patients at high risk of metastasis. PMID:27034329

  15. Gamma delta T cells and the immune response to respiratory syncytial virus infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'd T cells are a subset of nonconventional T cells that play a critical role in bridging the innate and adaptive arms of the immune system. 'd T cells are particularly abundant in ruminant species and may constitute of up 60% of the circulating lymphocyte pool in young cattle. The frequency of circ...

  16. Regulatory T Cell Effect on CD8(+) T Cell Responses to Human Herpesvirus 8 Infection and Development of Kaposi's Sarcoma.

    PubMed

    Lepone, Lauren M; Rappocciolo, Giovanna; Piazza, Paolo A; Campbell, Diana M; Jenkins, Frank J; Rinaldo, Charles R

    2017-03-02

    We assessed CD8(+) T cell reactivity to human herpesvirus 8 (HHV-8; Kaposi's sarcoma [KS]-associated herpesvirus) and the role of CD4(+)CD25(hi)FoxP3(+) regulatory T cells (Treg) in HHV-8- and HIV-coinfected participants of the Multicenter AIDS Cohort Study who did or did not develop KS. There were similarly low CD8(+) T cell interferon-γ responses to MHC class I-restricted epitopes of HHV-8 lytic and latent proteins over 5.7 years before KS in participants who developed KS compared to those who did not. T cell reactivity to HHV-8 antigens was low relative to responses to a combination of cytomegalovirus, Epstein-Barr virus and influenza A virus (CEF) peptide epitopes, and dominant HIV peptide epitopes. There was no change in %Treg in the HHV-8- and HIV-coinfected participants who did not develop KS, whereas there was a significant increase in %Treg in HHV-8- and HIV-coinfected participants who developed KS beginning 1.8 years before development of KS. Removal of Treg enhanced HHV-8-specific T cell responses in HHV-8- and HIV-coinfected participants who did or did not develop KS, with a similar pattern observed in response to CEF and HIV peptides. Thus, long-term, low levels of anti-HHV-8 CD8(+) T cell reactivity were present in both HHV-8- and HIV-coinfected men who did and did not develop KS. This was related to moderately enhanced Treg function.

  17. Analysis of the T Cell Response to Zika Virus and Identification of a Novel CD8+ T Cell Epitope in Immunocompetent Mice

    PubMed Central

    Pardy, Ryan D.; Rajah, Maaran M.; Taylor, Nathan G.

    2017-01-01

    Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family. Although ZIKV infection is typically mild and self-limiting in healthy adults, infection has been associated with neurological symptoms such as Guillain-Barré syndrome, and a causal link has been established between fetal microcephaly and ZIKV infection during pregnancy. These risks, and the magnitude of the ongoing ZIKV pandemic, have created an urgent need for the development of animal models to study the immune response to ZIKV infection. Previous animal models have primarily focused on pathogenesis in immunocompromised mice. In this study, we provide a model of ZIKV infection in wild-type immunocompetent C57BL/6 mice, and have provided an analysis of the immune response to infection. We evaluated the activation of several innate immune cell types, and studied the kinetics, phenotype, and functionality of T cell responses to ZIKV infection. Our results demonstrate that ZIKV infection is mild in wild-type immunocompetent C57BL/6 mice, resulting in minimal morbidity. Our data establish that at the peak of the adaptive response, antigen-experienced CD4+ T cells polarize to a Th1 phenotype, and antigen-experienced CD8+ T cells exhibit an activated effector phenotype, producing both effector cytokines and cytolytic molecules. Furthermore, we have identified a novel ZIKV CD8+ T cell epitope in the envelope protein that is recognized by the majority of responding cells. Our model provides an important reference point that will help dissect the impact of polymorphisms in the circulating ZIKV strains on the immune response and ZIKV pathogenesis. In addition, the identification of a ZIKV epitope will allow for the design of tetramers to study epitope-specific T cell responses, and will have important implications for the design and development of ZIKV vaccine strategies. PMID:28231312

  18. Analysis of the T Cell Response to Zika Virus and Identification of a Novel CD8+ T Cell Epitope in Immunocompetent Mice.

    PubMed

    Pardy, Ryan D; Rajah, Maaran M; Condotta, Stephanie A; Taylor, Nathan G; Sagan, Selena M; Richer, Martin J

    2017-02-01

    Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family. Although ZIKV infection is typically mild and self-limiting in healthy adults, infection has been associated with neurological symptoms such as Guillain-Barré syndrome, and a causal link has been established between fetal microcephaly and ZIKV infection during pregnancy. These risks, and the magnitude of the ongoing ZIKV pandemic, have created an urgent need for the development of animal models to study the immune response to ZIKV infection. Previous animal models have primarily focused on pathogenesis in immunocompromised mice. In this study, we provide a model of ZIKV infection in wild-type immunocompetent C57BL/6 mice, and have provided an analysis of the immune response to infection. We evaluated the activation of several innate immune cell types, and studied the kinetics, phenotype, and functionality of T cell responses to ZIKV infection. Our results demonstrate that ZIKV infection is mild in wild-type immunocompetent C57BL/6 mice, resulting in minimal morbidity. Our data establish that at the peak of the adaptive response, antigen-experienced CD4+ T cells polarize to a Th1 phenotype, and antigen-experienced CD8+ T cells exhibit an activated effector phenotype, producing both effector cytokines and cytolytic molecules. Furthermore, we have identified a novel ZIKV CD8+ T cell epitope in the envelope protein that is recognized by the majority of responding cells. Our model provides an important reference point that will help dissect the impact of polymorphisms in the circulating ZIKV strains on the immune response and ZIKV pathogenesis. In addition, the identification of a ZIKV epitope will allow for the design of tetramers to study epitope-specific T cell responses, and will have important implications for the design and development of ZIKV vaccine strategies.

  19. Essential role for retinoic acid in the promotion of CD4+ T cell effector responses via retinoic acid receptor alpha

    PubMed Central

    Hall, J.A.; Cannons, J.L.; Grainger, J.R.; Santos, L.M. Dos; Hand, T.W.; Naik, S.; Wohlfert, E.A.; Chou, D.B.; Oldenhove, G.; Robinson, M.; Grigg, M.E.; Kastenmayer, R.; Schwartzberg, P.L.; Belkaid, Y.

    2012-01-01

    SUMMARY Vitamin A and its metabolite, retinoic acid (RA), have recently been implicated in the regulation of immune homeostasis via the peripheral induction of regulatory T cells. Here we show that RA is also required to elicit proinflammatory CD4+ helper T cell responses to infection and mucosal vaccination. Retinoic acid receptor alpha (RARα) is the critical mediator of these effects. Strikingly, antagonism of RAR signaling and deficiency in RARα(Rara−/−) results in a cell autonomous CD4+ T cell activation defect. Altogether, these findings reveal a fundamental role for the RA/RARα axis in the development of both regulatory and inflammatory arms of adaptive immunity and establish nutritional status as a broad regulator of adaptive T cell responses. PMID:21419664

  20. Dimethyl Fumarate Therapy Significantly Improves the Responsiveness of T Cells in Multiple Sclerosis Patients for Immunoregulation by Regulatory T Cells

    PubMed Central

    Schlöder, Janine; Berges, Carsten; Luessi, Felix; Jonuleit, Helmut

    2017-01-01

    Multiple sclerosis (MS) is a chronic autoimmune disease caused by an insufficient suppression of autoreactive T lymphocytes. One reason for the lack of immunological control is the reduced responsiveness of T effector cells (Teff) for the suppressive properties of regulatory T cells (Treg), a process termed Treg resistance. Here we investigated whether the disease-modifying therapy of relapsing-remitting MS (RRMS) with dimethyl fumarate (DMF) influences the sensitivity of T cells in the peripheral blood of patients towards Treg-mediated suppression. We demonstrated that DMF restores responsiveness of Teff to the suppressive function of Treg in vitro, presumably by down-regulation of interleukin-6R (IL-6R) expression on T cells. Transfer of human immune cells into immunodeficient mice resulted in a lethal graft-versus-host reaction triggered by human CD4+ Teff. This systemic inflammation can be prevented by activated Treg after transfer of immune cells from DMF-treated MS patients, but not after injection of Treg-resistant Teff from therapy-naïve MS patients. Furthermore, after DMF therapy, proliferation and expansion of T cells and the immigration into the spleen of the animals is reduced and modulated by activated Treg. In summary, our data reveals that DMF therapy significantly improves the responsiveness of Teff in MS patients to immunoregulation. PMID:28134847

  1. Adoptive immunotherapy for cancer: harnessing the T cell response.

    PubMed

    Restifo, Nicholas P; Dudley, Mark E; Rosenberg, Steven A

    2012-03-22

    Immunotherapy based on the adoptive transfer of naturally occurring or gene-engineered T cells can mediate tumour regression in patients with metastatic cancer. Here, we discuss progress in the use of adoptively transferred T cells, focusing on how they can mediate tumour cell eradication. Recent advances include more accurate targeting of antigens expressed by tumours and the associated vasculature, and the successful use of gene engineering to re-target T cells before their transfer into the patient. We also describe how new research has helped to identify the particular T cell subsets that can most effectively promote tumour eradication.

  2. Adaptive immunity to leukemia is inhibited by cross-reactive induced regulatory T cells

    PubMed Central

    Manlove, Luke S.; Berquam-Vrieze, Katherine E.; Pauken, Kristen E.; Williams, Richard T.; Jenkins, Marc K.; Farrar, Michael A.

    2015-01-01

    BCR-ABL+ acute lymphoblastic leukemia patients have transient responses to current therapies. However, the fusion of BCR to ABL generates a potential leukemia-specific antigen that could be a target for immunotherapy. We demonstrate that the immune system can limit BCR-ABL+ leukemia progression although ultimately this immune response fails. To address how BCR-ABL+ leukemia escapes immune surveillance, we developed a peptide: MHC-II tetramer that labels endogenous BCR-ABL-specific CD4+ T cells. Naïve mice harbored a small population of BCR-ABL-specific T cells that proliferated modestly upon immunization. The small number of naïve BCR-ABL specific T cells was due to negative selection in the thymus, which depleted BCR-ABL specific T cells. Consistent with this observation, we saw that BCR-ABL specific T cells were cross-reactive with an endogenous peptide derived from ABL. Despite this cross-reactivity, the remaining population of BCR-ABL reactive T cells proliferated upon immunization with the BCR-ABL fusion peptide and adjuvant. In response to BCR-ABL+ leukemia, BCR-ABL specific T cells proliferated and converted into regulatory T cells (Treg cells), a process that was dependent on cross-reactivity with self-antigen, TGFβ1, and MHC-II antigen presentation by leukemic cells. Treg cells were critical for leukemia progression in C57Bl/6 mice, as transient Treg cell ablation led to extended survival of leukemic mice. Thus, BCR-ABL+ leukemia actively suppresses anti-leukemia immune responses by converting cross-reactive leukemia-specific T cells into Treg cells. PMID:26378075

  3. Leukocyte TLR5 deficiency inhibits atherosclerosis by reduced macrophage recruitment and defective T-cell responsiveness

    PubMed Central

    Ellenbroek, Guilielmus H.J.M.; van Puijvelde, Gijs H.M.; Anas, Adam A.; Bot, Martine; Asbach, Miriam; Schoneveld, Arjan; van Santbrink, Peter J.; Foks, Amanda C.; Timmers, Leo; Doevendans, Pieter A.; Pasterkamp, Gerard; Hoefer, Imo E.; van der Poll, Tom; Kuiper, Johan; de Jager, Saskia C.A.

    2017-01-01

    Toll-like receptors (TLR) provide a critical link between innate and adaptive immunity, both important players in atherosclerosis. Since evidence for the role of TLR5 is lacking, we aimed to establish this in the immune axis of atherosclerosis. We assessed the effect of the TLR5-specific ligand Flagellin on macrophage maturation and T-cell polarisation. Next, we generated TLR5−/−LDLr−/− chimeras to study the effect of hematopoietic TLR5 deficiency on atherosclerosis formation. Flagellin stimulation did not influence wildtype or TLR5−/− macrophage maturation. Only in wildtype macrophages, Flagellin exposure increased MCP-1 and IL6 expression. Flagellin alone reduced T-helper 1 proliferation, which was completely overruled in the presence of T-cell receptor activation. In vivo, hematopoietic TLR5 deficiency attenuated atherosclerotic lesion formation by ≈25% (1030*103 ± 63*103 vs. 792*103 ± 61*103 μm2; p = 0.013) and decreased macrophage area (81.3 ± 12.0 vs. 44.2 ± 6.6 μm2; p = 0.011). In TLR5−/− chimeric mice, we observed lower IL6 plasma levels (36.4 ± 5.6 vs. 15.1 ± 2.2 pg/mL; p = 0.003), lower (activated) splenic CD4+ T-cell content (32.3 ± 2.1 vs. 21.0 ± 1.2%; p = 0.0018), accompanied by impaired T-cell proliferative responses. In conclusion, hematopoietic TLR5 deficiency inhibits atherosclerotic lesion formation by attenuated macrophage accumulation and defective T-cell responsiveness. PMID:28202909

  4. Clonal selection in the human Vδ1 T cell repertoire indicates γδ TCR-dependent adaptive immune surveillance

    PubMed Central

    Davey, Martin S.; Willcox, Carrie R.; Joyce, Stephen P.; Ladell, Kristin; Kasatskaya, Sofya A.; McLaren, James E.; Hunter, Stuart; Salim, Mahboob; Mohammed, Fiyaz; Price, David A.; Chudakov, Dmitriy M.; Willcox, Benjamin E.

    2017-01-01

    γδ T cells are considered to be innate-like lymphocytes that respond rapidly to stress without clonal selection and differentiation. Here we use next-generation sequencing to probe how this paradigm relates to human Vδ2neg T cells, implicated in responses to viral infection and cancer. The prevalent Vδ1 T cell receptor (TCR) repertoire is private and initially unfocused in cord blood, typically becoming strongly focused on a few high-frequency clonotypes by adulthood. Clonal expansions have differentiated from a naive to effector phenotype associated with CD27 downregulation, retaining proliferative capacity and TCR sensitivity, displaying increased cytotoxic markers and altered homing capabilities, and remaining relatively stable over time. Contrastingly, Vδ2+ T cells express semi-invariant TCRs, which are present at birth and shared between individuals. Human Vδ1+ T cells have therefore evolved a distinct biology from the Vδ2+ subset, involving a central, personalized role for the γδ TCR in directing a highly adaptive yet unconventional form of immune surveillance. PMID:28248310

  5. Agonistic Anti-TIGIT Treatment Inhibits T Cell Responses in LDLr Deficient Mice without Affecting Atherosclerotic Lesion Development

    PubMed Central

    Foks, Amanda C.; Ran, Ingrid A.; Frodermann, Vanessa; Bot, Ilze; van Santbrink, Peter J.; Kuiper, Johan; van Puijvelde, Gijs H. M.

    2013-01-01

    Objective Co-stimulatory and co-inhibitory molecules are mainly expressed on T cells and antigen presenting cells and strongly orchestrate adaptive immune responses. Whereas co-stimulatory molecules enhance immune responses, signaling via co-inhibitory molecules dampens the immune system, thereby showing great therapeutic potential to prevent cardiovascular diseases. Signaling via co-inhibitory T cell immunoglobulin and ITIM domain (TIGIT) directly inhibits T cell activation and proliferation, and therefore represents a novel therapeutic candidate to specifically dampen pro-atherogenic T cell reactivity. In the present study, we used an agonistic anti-TIGIT antibody to determine the effect of excessive TIGIT-signaling on atherosclerosis. Methods and Results TIGIT was upregulated on CD4+ T cells isolated from mice fed a Western-type diet in comparison with mice fed a chow diet. Agonistic anti-TIGIT suppressed T cell activation and proliferation both in vitro and in vivo. However, agonistic anti-TIGIT treatment of LDLr−/− mice fed a Western-type diet for 4 or 8 weeks did not affect atherosclerotic lesion development in comparison with PBS and Armenian Hamster IgG treatment. Furthermore, elevated percentages of dendritic cells were observed in the blood and spleen of agonistic anti-TIGIT-treated mice. Additionally, these cells showed an increased activation status but decreased IL-10 production. Conclusions Despite the inhibition of splenic T cell responses, agonistic anti-TIGIT treatment does not affect initial atherosclerosis development, possibly due to increased activity of dendritic cells. PMID:24376654

  6. Regulatory T cells in tumor-associated tertiary lymphoid structures suppress anti-tumor T cell responses

    PubMed Central

    Joshi, Nikhil S.; Akama-Garren, Elliot H.; Lu, Yisi; Lee, Da-Yae; Chang, Gregory P.; Li, Amy; DuPage, Michel; Tammela, Tuomas; Kerper, Natanya R.; Farago, Anna F.; Robbins, Rebecca; Crowley, Denise M.; Bronson, Roderick T.; Jacks, Tyler

    2016-01-01

    SUMMARY Infiltration of regulatory T (Treg) cells into many tumor types correlates with poor patient prognoses. However, mechanisms of intratumoral Treg cell function remain to be elucidated. We investigated Treg cell function in a genetically-engineered mouse lung adenocarcinoma model and found Treg cells suppress anti-tumor responses in tumor-associated tertiary lymphoid structures (TA-TLS). TA-TLS have been described in human lung cancers, but their function remains to be determined. TLS in this model were spatially associated with >90% of tumors and facilitated interactions between T cells and tumor-antigen presenting dendritic cells (DCs). Costimulatory ligand expression by DCs and T cell proliferation rates increased in TA-TLS upon Treg cell depletion, leading to tumor destruction. Thus, we propose Treg cells in TA-TLS can inhibit endogenous immune responses against tumors, and targeting these cells may provide therapeutic benefit for cancer patients. PMID:26341400

  7. The T cell response to secreted antigens of Mycobacterium tuberculosis.

    PubMed

    Andersen, P

    1994-10-01

    Recent information from several laboratories points to proteins secreted from live Mycobacterium tuberculosis as being involved in protective immunity. We have studied protein release from M. tuberculosis during growth and have defined 3 different groups of proteins: excreted proteins, secreted proteins of the outer cell wall and cytoplasmic proteins released at late culture timepoints. These findings have lead to the definition of a short-term culture filtrate (ST-CF) enriched in excreted/secreted proteins and with a minimal content of autolytic products. ST-CF was tested as antigen in experimental vaccines against tuberculosis. A vaccine based on the adjuvant dimethyldioctadecylammonium chloride (DDA) was constructed and demonstrated to induce a potent cell mediated immune response of the Th-1 type. The vaccine was tested in parallel with a BCG standard vaccine and both vaccines induced a highly significant protection of the same magnitude. Molecules within the Ag85 complex and a 6-kDA secreted protein were mapped as the major antigenic targets for long-lived T cells involved in protective immunity against M. tuberculosis.

  8. Antigen-Specific B Cells Reactivate an Effective Cytotoxic T Cell Response against Phagocytosed Salmonella through Cross-Presentation

    PubMed Central

    de Wit, Jelle; Souwer, Yuri; Jorritsma, Tineke; Klaasse Bos, Hanny; ten Brinke, Anja; Neefjes, Jacques; van Ham, S. Marieke

    2010-01-01

    Background The eradication of facultative intracellular bacterial pathogens, like Salmonella typhi, requires the concerted action of both the humoral immune response and the cytotoxic CD8+ T cell response. Dendritic cells (DCs) are considered to orchestrate the cytotoxic CD8+ T cell response via cross-presentation of bacterial antigens onto MHC class I molecules. Cross-presentation of Salmonella by DCs however, is accompanied by the induction of apoptosis in the DCs. Besides antibody production, B cells are required to clear Salmonella infection for other unknown reasons. Methodology/Principal Findings Here we show that Salmonella-specific B cells that phagocytose Salmonella upon BCR-ligation reactivate human memory CD8+ T cells via cross-presentation yielding a Salmonella-specific cytotoxic T cell response. The reactivation of CD8+ T cells is dependent on CD4+ T cell help. Unlike the DCs, B cell-mediated cross-presentation of Salmonella does not coincide with apoptosis. Conclusions/Significance B cells form a new player in the activation of the cytotoxic effector arm of the immune response and the generation of effective adaptive immunity in Salmonella infection. PMID:20885961

  9. γδ T-Cells: Potential Regulators of the Post-Burn Inflammatory Response

    PubMed Central

    Schwacha, Martin G.

    2009-01-01

    Burn injury induces an immunopathological response that can contribute to the development of a systemic inflammatory response (SIRS) and subsequent multiple organ failure. While, multiple immune cells type (T-cells, macrophages, neutrophils) are involved in this response, recent evidence suggests that a unique T-cell subset, γδ T-cells are central in the response to injury. While γδ T-cells represent only a small percentage of the total T-cell population, they display specific functional characteristics that uniquely position them in the immune/inflammatory axis to influence a number of important aspects of the body’s response to burn injury. This review will focus on the potential regulator role of γδ T-cells in immunopathological response following burn injury and thereby their potential as therapeutic targets for modulation of post-burn inflammation and healing. PMID:18951718

  10. Low-affinity CD4+ T cells are major responders in the primary immune response

    PubMed Central

    Martinez, Ryan J.; Andargachew, Rakieb; Martinez, Hunter A.; Evavold, Brian D.

    2016-01-01

    A robust primary immune response has been correlated with the precursor number of antigen-specific T cells, as identified using peptide MHCII tetramers. However, these tetramers identify only the highest-affinity T cells. Here we show the entire CD4+ T-cell repertoire, inclusive of low-affinity T cells missed by tetramers, using a T-cell receptor (TCR) signalling reporter and micropipette assay to quantify naive precursors and expanded populations. In vivo limiting dilution assays reveal hundreds more precursor T cells than previously thought, with higher-affinity tetramer-positive T cells, comprising only 5–30% of the total antigen-specific naive repertoire. Lower-affinity T cells maintain their predominance as the primary immune response progresses, with no enhancement of survival of T cells with high-affinity TCRs. These findings demonstrate that affinity for antigen does not control CD4+ T-cell entry into the primary immune response, as a diverse range in affinity is maintained from precursor through peak of T-cell expansion. PMID:27976744

  11. Low-affinity CD4+ T cells are major responders in the primary immune response.

    PubMed

    Martinez, Ryan J; Andargachew, Rakieb; Martinez, Hunter A; Evavold, Brian D

    2016-12-15

    A robust primary immune response has been correlated with the precursor number of antigen-specific T cells, as identified using peptide MHCII tetramers. However, these tetramers identify only the highest-affinity T cells. Here we show the entire CD4+ T-cell repertoire, inclusive of low-affinity T cells missed by tetramers, using a T-cell receptor (TCR) signalling reporter and micropipette assay to quantify naive precursors and expanded populations. In vivo limiting dilution assays reveal hundreds more precursor T cells than previously thought, with higher-affinity tetramer-positive T cells, comprising only 5-30% of the total antigen-specific naive repertoire. Lower-affinity T cells maintain their predominance as the primary immune response progresses, with no enhancement of survival of T cells with high-affinity TCRs. These findings demonstrate that affinity for antigen does not control CD4+ T-cell entry into the primary immune response, as a diverse range in affinity is maintained from precursor through peak of T-cell expansion.

  12. CD4+ T cells are not required for the induction of dengue virus-specific CD8+ T cell or antibody responses but contribute to protection after vaccination.

    PubMed

    Yauch, Lauren E; Prestwood, Tyler R; May, Monica M; Morar, Malika M; Zellweger, Raphaël M; Peters, Bjoern; Sette, Alessandro; Shresta, Sujan

    2010-11-01

    The contribution of T cells to the host response to dengue virus (DENV) infection is not well understood. We previously demonstrated a protective role for CD8(+) T cells during primary DENV infection using a mouse-passaged DENV strain and IFN-α/βR(-/-) C57BL/6 mice, which are susceptible to DENV infection. In this study, we examine the role of CD4(+) T cells during primary DENV infection. Four I-A(b)-restricted epitopes derived from three of the nonstructural DENV proteins were identified. CD4(+) T cells expanded and were activated after DENV infection, with peak activation occurring on day 7. The DENV-specific CD4(+) T cells expressed intracellular IFN-γ, TNF, IL-2, and CD40L, and killed peptide-pulsed target cells in vivo. Surprisingly, depletion of CD4(+) T cells before DENV infection had no effect on viral loads. Consistent with this observation, CD4(+) T cell depletion did not affect the DENV-specific IgG or IgM Ab titers or their neutralizing activity, or the DENV-specific CD8(+) T cell response. However, immunization with the CD4(+) T cell epitopes before infection resulted in significantly lower viral loads. Thus, we conclude that whereas CD4(+) T cells are not required for controlling primary DENV infection, their induction by immunization can contribute to viral clearance. These findings suggest inducing anti-DENV CD4(+) T cell responses by vaccination may be beneficial.

  13. Understanding delayed T-cell priming, lung recruitment, and airway luminal T-cell responses in host defense against pulmonary tuberculosis.

    PubMed

    Shaler, Christopher R; Horvath, Carly; Lai, Rocky; Xing, Zhou

    2012-01-01

    Mycobacterium tuberculosis (M.tb), the causative bacterium of pulmonary tuberculosis (TB), is a serious global health concern. Central to M.tb effective immune avoidance is its ability to modulate the early innate inflammatory response and prevent the establishment of adaptive T-cell immunity for nearly three weeks. When compared with other intracellular bacterial lung pathogens, such as Legionella pneumophila, or even closely related mycobacterial species such as M. smegmatis, this delay is astonishing. Customarily, the alveolar macrophage (AM) acts as a sentinel, detecting and alerting surrounding cells to the presence of an invader. However, in the case of M.tb, this may be impaired, thus delaying the recruitment of antigen-presenting cells (APCs) to the lung. Upon uptake by APC populations, M.tb is able to subvert and delay the processing of antigen, MHC class II loading, and the priming of effector T cell populations. This delay ultimately results in the deferred recruitment of effector T cells to not only the lung interstitium but also the airway lumen. Therefore, it is of upmost importance to dissect the mechanisms that contribute to the delayed onset of immune responses following M.tb infection. Such knowledge will help design the most effective vaccination strategies against pulmonary TB.

  14. Direct presentation regulates the magnitude of the CD8+ T cell response to cell-associated antigen through prolonged T cell proliferation.

    PubMed

    Tatum, Angela M; Watson, Alan M; Schell, Todd D

    2010-09-01

    The magnitude and complexity of Ag-specific CD8(+) T cell responses is determined by intrinsic properties of the immune system and extrinsic factors, such as vaccination. We evaluated mechanisms that regulate the CD8(+) T cell response to two distinct determinants derived from the same protein Ag, SV40 T Ag (T Ag), following immunization of C57BL/6 mice with T Ag-transformed cells. The results show that direct presentation of T cell determinants by T Ag-transformed cells regulates the magnitude of the CD8(+) T cell response in vivo but not the immunodominance hierarchy. The immunodominance hierarchy was reversed in a dose-dependent manner by addition of excess naive T cells targeting the subdominant determinant. However, T cell competition played only a minor role in limiting T cell accumulation under physiological conditions. We found that the magnitude of the T cell response was regulated by the ability of T Ag-transformed cells to directly present the T Ag determinants. The hierarchy of the CD8(+) T cell response was maintained when Ag presentation in vivo was restricted to cross-presentation, but the presence of T Ag-transformed cells capable of direct presentation dramatically enhanced T cell accumulation at the peak of the response. This enhancement was due to a prolonged period of T cell proliferation, resulting in a delay in T cell contraction. Our findings reveal that direct presentation by nonprofessional APCs can dramatically enhance accumulation of CD8(+) T cells during the primary response, revealing a potential strategy to enhance vaccination approaches.

  15. Adenovirus serotype 5 vaccine vectors trigger IL-27-dependent inhibitory CD4+ T cell responses that impair CD8+ T cell function

    PubMed Central

    Larocca, Rafael A.; Provine, Nicholas M.; Aid, Malika; Iampietro, M. Justin; Borducchi, Erica N.; Badamchi-Zadeh, Alexander; Abbink, Peter; Ng’ang’a, David; Bricault, Christine A.; Blass, Eryn; Penaloza-MacMaster, Pablo; Stephenson, Kathryn E.; Barouch, Dan H.

    2017-01-01

    Adenovirus serotype 5 (Ad5) vaccine vectors elicit robust CD8+ T cell responses, but these responses typically exhibit a partially exhausted phenotype. However, the immunologic mechanism by which Ad5 vectors induce dysfunctional CD8+ T cells has not previously been elucidated. Here we demonstrate that, following immunization of B6 mice, Ad5 vectors elicit antigen-specific IL-10+CD4+ T cells with a distinct transcriptional profile in a dose-dependent fashion. In rhesus monkeys, we similarly observed upregulated expression of IL-10 and PD-1 by CD4+ T cells following Ad5 vaccination. These cells markedly suppressed vaccine-elicited CD8+ T cell responses in vivo and IL-10 blockade increased the frequency and functionality of antigen-specific CD8+ T cells as well as improved protective efficacy against challenge with recombinant Listeria monocytogenes. Moreover, induction of these inhibitory IL-10+CD4+ T cells correlated with IL-27 expression and IL-27 blockade substantially improved CD4+ T cell functionality. These data highlight a role for IL-27 in the induction of inhibitory IL-10+CD4+ T cells, which suppress CD8+ T cell magnitude and function following Ad5 vector immunization. A deeper understanding of the cytokine networks and transcriptional profiles induced by vaccine vectors should lead to strategies to improve the immunogenicity and protective efficacy of viral vector-based vaccines. PMID:28239679

  16. Virus-specific CD4+ and CD8+ cytotoxic T-cell responses and long-term T-cell memory in individuals vaccinated against polio.

    PubMed

    Wahid, Rahnuma; Cannon, Martin J; Chow, Marie

    2005-05-01

    The presence of poliovirus (PV)-specific CD4(+) T cells in individuals vaccinated against polio has been shown, but CD8(+) T-cell responses have not been described. Here, we functionally characterize the CD4(+) T-cell response and show for the first time that dendritic cells and macrophages can stimulate PV-specific CD8(+) T-cell responses in vitro from vaccinees. Both CD4(+) T and CD8(+) T cells secrete gamma interferon in response to PV antigens and are cytotoxic via the perforin/granzyme B-mediated pathway. Furthermore, the T cells also recognize and kill Sabin 1 vaccine-infected targets. The macrophage-stimulated CD4(+) T and CD8(+) T cells most likely represent memory T cells that persist for long periods in vaccinated individuals. Thus, immunity to PV vaccination involves not only an effective neutralizing antibody titer but also long-term CD4(+) and CD8(+) cytotoxic T-cell responses.

  17. Signaling lymphocyte activation molecule-associated protein is a negative regulator of the CD8 T cell response in mice.

    PubMed

    Chen, Gang; Tai, Albert K; Lin, Miao; Chang, Francesca; Terhorst, Cox; Huber, Brigitte T

    2005-08-15

    The primary manifestation of X-linked lymphoproliferative syndrome, caused by a dysfunctional adapter protein, signaling lymphocyte activation molecule-associated protein (SAP), is an excessive T cell response upon EBV infection. Using the SAP-/- mouse as a model system for the human disease, we compared the response of CD8+ T cells from wild-type (wt) and mutant mice to various stimuli. First, we observed that CD8+ T cells from SAP-/- mice proliferate more vigorously than those from wt mice upon CD3/CD28 cross-linking in vitro. Second, we analyzed the consequence of SAP deficiency on CTL effector function and homeostasis. For this purpose, SAP-/- and wt mice were infected with the murine gamma-herpesvirus 68 (MHV-68). At 2 wk postinfection, the level of viral-specific CTL was much higher in mutant than in wt mice, measured both ex vivo and in vivo. In addition, we established that throughout 45 days of MHV-68 infection the frequency of virus-specific CD8+ T cells producing IFN-gamma was significantly higher in SAP-/- mice. Consequently, the level of latent infection by MHV-68 was considerably lower in SAP-/- mice, which indicates that SAP-/- CTL control this infection more efficiently than wt CTL. Finally, we found that the Vbeta4-specific CD8+ T cell expansion triggered by MHV-68 infection is also enhanced and prolonged in SAP-/- mice. Taken together, our data indicate that SAP functions as a negative regulator of CD8+ T cell activation.

  18. Augmenting antitumor T-cell responses to mimotope vaccination by boosting with native tumor antigens.

    PubMed

    Buhrman, Jonathan D; Jordan, Kimberly R; U'ren, Lance; Sprague, Jonathan; Kemmler, Charles B; Slansky, Jill E

    2013-01-01

    Vaccination with antigens expressed by tumors is one strategy for stimulating enhanced T-cell responses against tumors. However, these peptide vaccines rarely result in efficient expansion of tumor-specific T cells or responses that protect against tumor growth. Mimotopes, or peptide mimics of tumor antigens, elicit increased numbers of T cells that crossreact with the native tumor antigen, resulting in potent antitumor responses. Unfortunately, mimotopes may also elicit cells that do not crossreact or have low affinity for tumor antigen. We previously showed that one such mimotope of the dominant MHC class I tumor antigen of a mouse colon carcinoma cell line stimulates a tumor-specific T-cell clone and elicits antigen-specific cells in vivo, yet protects poorly against tumor growth. We hypothesized that boosting the mimotope vaccine with the native tumor antigen would focus the T-cell response elicited by the mimotope toward high affinity, tumor-specific T cells. We show that priming T cells with the mimotope, followed by a native tumor-antigen boost, improves tumor immunity compared with T cells elicited by the same prime with a mimotope boost. Our data suggest that the improved tumor immunity results from the expansion of mimotope-elicited tumor-specific T cells that have increased avidity for the tumor antigen. The enhanced T cells are phenotypically distinct and enriched for T-cell receptors previously correlated with improved antitumor immunity. These results suggest that incorporation of native antigen into clinical mimotope vaccine regimens may improve the efficacy of antitumor T-cell responses.

  19. Loss of naive T cells and repertoire constriction predict poor response to vaccination in old primates.

    PubMed

    Cicin-Sain, Luka; Smyk-Pearson, Susan; Smyk-Paerson, Sue; Currier, Noreen; Byrd, Laura; Koudelka, Caroline; Robinson, Tammie; Swarbrick, Gwendolyn; Tackitt, Shane; Legasse, Alfred; Fischer, Miranda; Nikolich-Zugich, Dragana; Park, Byung; Hobbs, Theodore; Doane, Cynthia J; Mori, Motomi; Axthelm, Michael K; Axthelm, Michael T; Lewinsohn, Deborah A; Nikolich-Zugich, Janko

    2010-06-15

    Aging is usually accompanied by diminished immune protection upon infection or vaccination. Although aging results in well-characterized changes in the T cell compartment of long-lived, outbred, and pathogen-exposed organisms, their relevance for primary Ag responses remain unclear. Therefore, it remains unclear whether and to what extent the loss of naive T cells, their partial replacement by oligoclonal memory populations, and the consequent constriction of TCR repertoire limit the Ag responses in aging primates. We show in this study that aging rhesus monkeys (Macaca mulatta) exhibit poor CD8 T cell and B cell responses in the blood and poor CD8 responses in the lungs upon vaccination with the modified vaccinia strain Ankara. The function of APCs appeared to be maintained in aging monkeys, suggesting that the poor response was likely intrinsic to lymphocytes. We found that the loss of naive CD4 and CD8 T cells, and the appearance of persisting T cell clonal expansions predicted poor CD8 responses in individual monkeys. There was strong correlation between early CD8 responses in the transitory CD28+ CD62L- CD8+ T cell compartment and the peak Ab titers upon boost in individual animals, as well as a correlation of both parameters of immune response to the frequency of naive CD8+ T cells in old but not in adult monkeys. Therefore, our results argue that T cell repertoire constriction and naive cell loss have prognostic value for global immune function in aging primates.

  20. THE INITIAL PHASE OF AN IMMUNE RESPONSE FUNCTIONS TO ACTIVATE REGULATORY T CELLS

    PubMed Central

    O’Gorman, William E.; Dooms, Hans; Thorne, Steve H.; Kuswanto, Wilson F.; Simonds, Erin F.; Krutzik, Peter O.; Nolan, Garry P.; Abbas, Abul K.

    2009-01-01

    An early reaction of CD4+ T lymphocytes to antigen is the production of cytokines, notably IL-2. In order to detect cytokine dependent responses, naive antigen-specific T cells were stimulated in vivo and the presence of phosphorylated STAT5 molecules was used to identify the cell populations responding to IL-2. Within hours of T-cell priming, IL-2-dependent STAT5 phosphorylation occurred primarily in Foxp3+ regulatory T cells. In contrast, the antigen-specific T cells received STAT5 signals only after repeated antigen exposure or memory differentiation. Regulatory T cells receiving IL-2 signals proliferated and developed enhanced suppressive activity. These results indicate that one of the earliest events in a T cell response is the activation of endogenous regulatory cells, potentially to prevent autoimmunity. PMID:19542444

  1. CD4+ T-Cell-Independent Secondary Immune Responses to Pneumocystis Pneumonia

    PubMed Central

    de la Rua, Nicholas M.; Samuelson, Derrick R.; Charles, Tysheena P.; Welsh, David A.; Shellito, Judd E.

    2016-01-01

    Pneumocystis pneumonia is a major cause of morbidity and mortality among immunocompromised patients, especially in the context of HIV/AIDS. In the murine model of Pneumocystis pneumonia, CD4+ T-cells are required for clearance of a primary infection of Pneumocystis, but not the memory recall response. We hypothesized that the memory recall response in the absence of CD4+ T-cells is mediated by a robust memory humoral response, CD8+ T-cells, and IgG-mediated phagocytosis by alveolar macrophages. To investigate the role of CD8+ T-cells and alveolar macrophages in the immune memory response to Pneumocystis, mice previously challenged with Pneumocystis were depleted of CD8+ T-cells or alveolar macrophages prior to re-infection. Mice depleted of CD4+ T-cells prior to secondary challenge cleared Pneumocystis infection within 48 h identical to immunocompetent mice during a secondary memory recall response. However, loss of CD8+ T-cells or macrophages prior to the memory recall response significantly impaired Pneumocystis clearance. Specifically, mice depleted of CD8+ T-cells or alveolar macrophages had significantly higher fungal burden in the lungs. Furthermore, loss of alveolar macrophages significantly skewed the lung CD8+ T-cell response toward a terminally differentiated effector memory population and increased the percentage of IFN-γ+ CD8+ T-cells. Finally, Pneumocystis-infected animals produced significantly more bone marrow plasma cells and Pneumocystis-specific IgG significantly increased macrophage-mediated killing of Pneumocystis in vitro. These data suggest that secondary immune memory responses to Pneumocystis are mediated, in part, by CD8+ T-cells, alveolar macrophages, and the production of Pneumocystis-specific IgG. PMID:27242785

  2. CD4(+) T-Cell-Independent Secondary Immune Responses to Pneumocystis Pneumonia.

    PubMed

    de la Rua, Nicholas M; Samuelson, Derrick R; Charles, Tysheena P; Welsh, David A; Shellito, Judd E

    2016-01-01

    Pneumocystis pneumonia is a major cause of morbidity and mortality among immunocompromised patients, especially in the context of HIV/AIDS. In the murine model of Pneumocystis pneumonia, CD4(+) T-cells are required for clearance of a primary infection of Pneumocystis, but not the memory recall response. We hypothesized that the memory recall response in the absence of CD4(+) T-cells is mediated by a robust memory humoral response, CD8(+) T-cells, and IgG-mediated phagocytosis by alveolar macrophages. To investigate the role of CD8(+) T-cells and alveolar macrophages in the immune memory response to Pneumocystis, mice previously challenged with Pneumocystis were depleted of CD8(+) T-cells or alveolar macrophages prior to re-infection. Mice depleted of CD4(+) T-cells prior to secondary challenge cleared Pneumocystis infection within 48 h identical to immunocompetent mice during a secondary memory recall response. However, loss of CD8(+) T-cells or macrophages prior to the memory recall response significantly impaired Pneumocystis clearance. Specifically, mice depleted of CD8(+) T-cells or alveolar macrophages had significantly higher fungal burden in the lungs. Furthermore, loss of alveolar macrophages significantly skewed the lung CD8(+) T-cell response toward a terminally differentiated effector memory population and increased the percentage of IFN-γ(+) CD8(+) T-cells. Finally, Pneumocystis-infected animals produced significantly more bone marrow plasma cells and Pneumocystis-specific IgG significantly increased macrophage-mediated killing of Pneumocystis in vitro. These data suggest that secondary immune memory responses to Pneumocystis are mediated, in part, by CD8(+) T-cells, alveolar macrophages, and the production of Pneumocystis-specific IgG.

  3. Comparison of influenza and SIV specific CD8 T cell responses in macaques.

    PubMed

    Jegaskanda, Sinthujan; Reece, Jeanette C; De Rose, Robert; Stambas, John; Sullivan, Lucy; Brooks, Andrew G; Kent, Stephen J; Sexton, Amy

    2012-01-01

    Macaques are a potentially useful non-human primate model to compare memory T-cell immunity to acute virus pathogens such as influenza virus and effector T-cell responses to chronic viral pathogens such as SIV. However, immunological reagents to study influenza CD8(+) T-cell responses in the macaque model are limited. We recently developed an influenza-SIV vaccination model of pigtail macaques (Macaca nemestrina) and used this to study both influenza-specific and SIV-specific CD8(+) T-cells in 39 pigtail macaques expressing the common Mane-A*10(+) (Mane-A01*084) MHC-I allele. To perform comparative studies between influenza and SIV responses a common influenza nucleoprotein-specific CD8(+) T-cell response was mapped to a minimal epitope (termed RA9), MHC-restricted to Mane-A*10 and an MHC tetramer developed to study this response. Influenza-specific memory CD8(+) T-cell response maintained a highly functional profile in terms of multitude of effector molecule expression (CD107a, IFN-γ, TNF-α, MIP-1β and IL-2) and showed high avidity even in the setting of SIV infection. In contrast, within weeks following active SIV infection, SIV-specific CD8(+) effector T-cells expressed fewer cytokines/degranulation markers and had a lower avidity compared to influenza specific CD8(+) T-cells. Further, the influenza specific memory CD8 T-cell response retained stable expression of the exhaustion marker programmed death-marker-1 (PD-1) and co-stimulatory molecule CD28 following infection with SIV. This contrasted with the effector SIV-specific CD8(+) T-cells following SIV infection which expressed significantly higher amounts of PD-1 and lower amounts of CD28. Our results suggest that strategies to maintain a more functional CD8(+) T-cell response, profile may assist in controlling HIV disease.

  4. ICAM-1-dependent tuning of memory CD8 T-cell responses following acute infection.

    PubMed

    Cox, Maureen A; Barnum, Scott R; Bullard, Daniel C; Zajac, Allan J

    2013-01-22

    CD8 T-cell responses are critical for protection against intracellular pathogens and tumors. The induction and properties of these responses are governed by a series of integrated processes that rely heavily on cell-cell interactions. Intercellular adhesion molecule (ICAM)-1 functions to enhance the strength of antigenic stimulation, extend the duration of contact with antigen-presenting cells, and augment cytokine signals, which are all factors that influence peripheral CD8 T-cell differentiation. Although previous studies suggest that ICAM-1 is essential for establishing memory T-cell populations following peptide immunization, the roles of ICAM-1 in antiviral cellular immunity are less well understood. Here we show that, following a prototypic acute viral infection, the formation and maintenance of memory-phenotype CD127(hi), KLRG-1(lo) CD8 T cells does not require ICAM-1. Nevertheless, ICAM-1 expression on nonlymphocytes dictates the phenotypic and functional attributes of the antiviral CD8 T-cell populations that develop and promotes the gradual attrition of residual effector-like CD127(lo), KLRG-1(hi) CD8 T cells during the memory phase of the response. Although memory T cells do emerge and are maintained if ICAM-1 expression is abolished, the secondary proliferative capacity of these T cells is severely curtailed. Collectively, these studies reveal potential dual roles for ICAM-1 in both promoting the decay of effector responses and programming the sensitivity of memory CD8 T cells to secondary stimuli.

  5. Inhibition of altered peptide ligand-mediated antagonism of human GAD65-responsive CD4+ T cells by non-antagonizable T cells.

    PubMed

    Gebe, John A; Masewicz, Susan A; Kochik, Sharon A; Reijonen, Helena; Nepom, Gerald T

    2004-12-01

    Altered peptide ligands derived from T cell-reactive self antigens have been shown to be protective therapeutic agents in animal models of autoimmunity. In this study we identified several altered peptide ligands derived from the type 1 diabetes-associated autoantigen human glutamic acid decarboxylase 65 (hGAD65) epitope that were capable of antagonizing a subset of a panel of human CD4(+) GAD65 (555-567)-responsive T cell clones derived from a diabetic individual. While no altered peptide ligand was able to antagonize all six clones in the T cell panel, a single-substituted peptide of isoleucine to methionine at position 561, which resides at the TCR contact p5 position, was able to antagonize five out of the six hGAD65-responsive clones. In a mixed T cell culture system we observed that altered peptide ligand-mediated antagonism is inhibited in a dose-dependent manner by the presence of non-antagonizable hGAD65 (555-567)-responsive T cells. From an analysis of the cytokines present in the mixed T cell cultures, interleukin-2 was sufficient to inhibit altered peptide ligand-induced antagonism. The inhibition of altered peptide ligand-mediated antagonism of self-antigen-responsive T cells by non-antagonizable T cells has implications in altered peptide ligand therapy where T cell antagonism is the goal.

  6. Tissue adaptation of regulatory and intraepithelial CD4+ T cells controls gut inflammation

    PubMed Central

    Sujino, Tomohisa; London, Mariya; Hoytema van Konijnenburg, David P.; Rendon, Tomiko; Buch, Thorsten; Silva, Hernandez M.; Lafaille, Juan J.; Reis, Bernardo S.; Mucida, Daniel

    2016-01-01

    Foxp3+ regulatory T cells in peripheral tissues (pTregs) are instrumental in limiting inflammatory responses to non-self antigens. Within the intestine, pTregs are located primarily in the lamina propria, while intraepithelial CD4+ T cells (CD4IELs), which also exhibit anti-inflammatory properties and depend on similar environmental cues, reside in the epithelium. Using intravital microscopy, we show distinct cell dynamics of intestinal Tregs and CD4IELs. Upon migration to the epithelium, Tregs lose Foxp3 and convert to CD4IELs in a microbiota-dependent fashion, an effect attributed to the loss of the transcription factor ThPOK. Finally, we demonstrate that pTregs and CD4IELs perform complementary roles in the regulation of intestinal inflammation. These results reveal intra-tissue specialization of anti-inflammatory T cells shaped by discrete niches of the intestine. PMID:27256884

  7. CARMA1 is necessary for optimal T cell responses in a murine model of allergic asthma.

    PubMed

    Ramadas, Ravisankar A; Roche, Marly I; Moon, James J; Ludwig, Thomas; Xavier, Ramnik J; Medoff, Benjamin D

    2011-12-15

    CARMA1 is a lymphocyte-specific scaffold protein necessary for T cell activation. Deletion of CARMA1 prevents the development of allergic airway inflammation in a mouse model of asthma due to a defect in naive T cell activation. However, it is unknown if CARMA1 is important for effector and memory T cell responses after the initial establishment of inflammation, findings that would be more relevant to asthma therapies targeted to CARMA1. In the current study, we sought to elucidate the role of CARMA1 in T cells that have been previously activated. Using mice in which floxed CARMA1 exons can be selectively deleted in T cells by OX40-driven Cre recombinase (OX40(+/Cre)CARMA1(F/F)), we report that CD4(+) T cells from these mice have impaired T cell reactivation responses and NF-κB signaling in vitro. Furthermore, in an in vivo recall model of allergic airway inflammation that is dependent on memory T cell function, OX40(+/Cre)CARMA1(F/F) mice have attenuated eosinophilic airway inflammation, T cell activation, and Th2 cytokine production. Using MHC class II tetramers, we demonstrate that the development and maintenance of Ag-specific memory T cells is not affected in OX40(+/Cre)CARMA1(F/F) mice. In addition, adoptive transfer of Th2-polarized OX40(+/Cre)CARMA1(F/F) Ag-specific CD4(+) T cells into wild-type mice induces markedly less airway inflammation in response to Ag challenge than transfer of wild-type Th2 cells. These data demonstrate a novel role for CARMA1 in effector and memory T cell responses and suggest that therapeutic strategies targeting CARMA1 could help treat chronic inflammatory disorders such as asthma.

  8. PRMT5-Selective Inhibitors Suppress Inflammatory T Cell Responses and Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Webb, Lindsay M.; Amici, Stephanie A.; Jablonski, Kyle A.; Savardekar, Himanshu; Panfil, Amanda R.; Li, Linsen; Zhou, Wei; Peine, Kevin; Karkhanis, Vrajesh; Bachelder, Eric M.; Ainslie, Kristy M.; Green, Patrick L.; Li, Chenglong; Baiocchi, Robert A.

    2017-01-01

    In the autoimmune disease multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), expansion of pathogenic, myelin-specific Th1 cell populations drives active disease; selectively targeting this process may be the basis for a new therapeutic approach. Previous studies have hinted at a role for protein arginine methylation in immune responses, including T cell–mediated autoimmunity and EAE. However, a conclusive role for the protein arginine methyltransferase (PRMT) enzymes that catalyze these reactions has been lacking. PRMT5 is the main PRMT responsible for symmetric dimethylation of arginine residues of histones and other proteins. PRMT5 drives embryonic development and cancer, but its role in T cells, if any, has not been investigated. In this article, we show that PRMT5 is an important modulator of CD4+ T cell expansion. PRMT5 was transiently upregulated during maximal proliferation of mouse and human memory Th cells. PRMT5 expression was regulated upstream by the NF-κB pathway, and it promoted IL-2 production and proliferation. Blocking PRMT5 with novel, highly selective small molecule PRMT5 inhibitors severely blunted memory Th expansion, with preferential suppression of Th1 cells over Th2 cells. In vivo, PRMT5 blockade efficiently suppressed recall T cell responses and reduced inflammation in delayed-type hypersensitivity and clinical disease in EAE mouse models. These data implicate PRMT5 in the regulation of adaptive memory Th cell responses and suggest that PRMT5 inhibitors may be a novel therapeutic approach for T cell–mediated inflammatory disease. PMID:28087667

  9. T-cell clones in human trichinellosis: Evidence for a mixed Th1/Th2 response.

    PubMed

    Della Bella, C; Benagiano, M; De Gennaro, M; Gomez-Morales, M A; Ludovisi, A; D'Elios, S; Luchi, S; Pozio, E; D'Elios, M M; Bruschi, F

    2017-03-01

    In humans, studies on the cellular immune response against Trichinella are scarce. Aim of this study was to characterize the cytokine profile of T cells specific for Trichinella britovi in trichinellosis patients. Peripheral blood mononuclear cells (PBMC) were obtained from five patients involved in a trichinellosis outbreak caused by T. britovi, which occurred in 2013 in Tuscany (Italy). All the patients resulted positive for Trichinella-specific IgG, IgE and presented eosinophilia. T cells were investigated for their proliferation to excretory/secretory antigens from Trichinella spiralis muscle larvae (TsES) and for their cytokine profile. A total of 284 CD4+ and 42 CD8+ T-cell clones were obtained from the TsES-specific T-cell lines from PBMC. All T-cell clones proliferated in response to mitogen. Of the 284 CD4+ T-cell clones generated from TsES-specific T-cell lines, 135 (47%) proliferated significantly to TsES; 26% CD8+ T-cell clones showed proliferation to TsES. In the series of the 135 TsES-specific CD4+ clones, 51% expressed a Th2 profile, 30% a Th0 and 19% Th1. In the series of the 11 TsES-specific CD8+ T-cell clones, 18% were Tc2, 45% Tc0 and 36% Tc1. In human trichinellosis, the cellular immune response is, during the chronic phase, mixed Th1/Th2.

  10. Regulatory T cell memory

    PubMed Central

    Rosenblum, Michael D.; Way, Sing Sing; Abbas, Abul K.

    2016-01-01

    Memory for antigen is a defining feature of adaptive immunity. Antigen-specific lymphocyte populations show an increase in number and function after antigen encounter and more rapidly re-expand upon subsequent antigen exposure. Studies of immune memory have primarily focused on effector B cells and T cells with microbial specificity, using prime challenge models of infection. However, recent work has also identified persistently expanded populations of antigen-specific regulatory T cells that protect against aberrant immune responses. In this Review, we consider the parallels between memory effector T cells and memory regulatory T cells, along with the functional implications of regulatory memory in autoimmunity, antimicrobial host defence and maternal fetal tolerance. In addition, we discuss emerging evidence for regulatory T cell memory in humans and key unanswered questions in this rapidly evolving field. PMID:26688349

  11. Plasticity of γδ T Cells: Impact on the Anti-Tumor Response

    PubMed Central

    Lafont, Virginie; Sanchez, Françoise; Laprevotte, Emilie; Michaud, Henri-Alexandre; Gros, Laurent; Eliaou, Jean-François; Bonnefoy, Nathalie

    2014-01-01

    The tumor immune microenvironment contributes to tumor initiation, progression, and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of γ and δ chains (γδ T cells) are of particular interest. γδ T cells can contribute to the immune response against many tumor types (lymphoma, myeloma, melanoma, breast, colon, lung, ovary, and prostate cancer) directly through their cytotoxic activity and indirectly by stimulating or regulating the biological functions of other cell types required for the initiation and establishment of the anti-tumor immune response, such as dendritic cells and cytotoxic CD8+ T cells. However, the notion that tumor-infiltrating γδ T cells are a good prognostic marker in cancer was recently challenged by studies showing that the presence of these cells in the tumor microenvironment was associated with poor prognosis in both breast and colon cancer. These findings suggest that γδ T cells may also display pro-tumor activities. Indeed, breast tumor-infiltrating γδ T cells could exert an immunosuppressive activity by negatively regulating dendritic cell maturation. Furthermore, recent studies demonstrated that signals from the microenvironment, particularly cytokines, can confer some plasticity to γδ T cells and promote their differentiation into γδ T cells with regulatory functions. This review focuses on the current knowledge on the functional plasticity of γδ T cells and its effect on their anti-tumor activities. It also discusses the putative mechanisms underlying γδ T cell expansion, differentiation, and recruitment in the tumor microenvironment. PMID:25538706

  12. A20 Curtails Primary but Augments Secondary CD8+ T Cell Responses in Intracellular Bacterial Infection

    PubMed Central

    Just, Sissy; Nishanth, Gopala; Buchbinder, Jörn H.; Wang, Xu; Naumann, Michael; Lavrik, Inna; Schlüter, Dirk

    2016-01-01

    The ubiquitin-modifying enzyme A20, an important negative feedback regulator of NF-κB, impairs the expansion of tumor-specific CD8+ T cells but augments the proliferation of autoimmune CD4+ T cells. To study the T cell-specific function of A20 in bacterial infection, we infected T cell-specific A20 knockout (CD4-Cre A20fl/fl) and control mice with Listeria monocytogenes. A20-deficient pathogen-specific CD8+ T cells expanded stronger resulting in improved pathogen control at day 7 p.i. Imaging flow cytometry revealed that A20-deficient Listeria-specific CD8+ T cells underwent increased apoptosis and necroptosis resulting in reduced numbers of memory CD8+ T cells. In contrast, the primary CD4+ T cell response was A20-independent. Upon secondary infection, the increase and function of pathogen-specific CD8+ T cells, as well as pathogen control were significantly impaired in CD4-Cre A20fl/fl mice. In vitro, apoptosis and necroptosis of Listeria-specific A20-deficient CD8+ T cells were strongly induced as demonstrated by increased caspase-3/7 activity, RIPK1/RIPK3 complex formation and more morphologically apoptotic and necroptotic CD8+ T cells. In vitro, A20 limited CD95L and TNF-induced caspase3/7 activation. In conclusion, T cell-specific A20 limited the expansion but reduced apoptosis and necroptosis of Listeria-specific CD8+ T cells, resulting in an impaired pathogen control in primary but improved clearance in secondary infection. PMID:28004776

  13. Modulation of innate immune responses during human T-cell leukemia virus (HTLV-1) pathogenesis.

    PubMed

    Olière, Stéphanie; Douville, Renée; Sze, Alexandre; Belgnaoui, S Mehdi; Hiscott, John

    2011-08-01

    Infection with the Human T-cell Leukemia virus type I (HTLV-1) retrovirus results in a number of diverse pathologies, including the aggressive, fatal T-cell malignancy adult T-cell leukemia (ATL) and the chronic, progressive neurologic disorder termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Worldwide, it is estimated there are 15-20 million HTLV-1-infected individuals; although the majority of HTLV-1-infected individuals remain asymptomatic carriers (AC) during their lifetime, 2-5% of AC develops either ATL or HAM/TSP, but never both. Regardless of asymptomatic status or clinical outcome, HTLV-1 carriers are at high risk of opportunistic infection. The progression to pathological HTLV-1 disease is in part attributed to the failure of the innate and adaptive immune system to control virus spread. The innate immune response against retroviral infection requires recognition of viral pathogen-associated molecular patterns (PAMPs) through pattern-recognition receptors (PRR) dependent pathways, leading to the induction of host antiviral and inflammatory responses. Recent studies have begun to characterize the interplay between HTLV-1 infection and the innate immune response and have identified distinct gene expression profiles in patients with ATL or HAM/TSP--upregulation of growth regulatory pathways in ATL and constitutive activation of antiviral and inflammatory pathways in HAM/STP. In this review, we provide an overview of the replicative lifecycle of HTLV-1 and the distinct pathologies associated with HTLV-1 infection. We also explore the innate immune mechanisms that respond to HTLV-1 infection, the strategies used by HTLV-1 to subvert these defenses and their contribution to HTLV-1-associated diseases.

  14. Dissecting memory T cell responses to TB: concerns using adoptive transfer into immunodeficient mice.

    PubMed

    Ancelet, Lindsay; Rich, Fenella J; Delahunt, Brett; Kirman, Joanna R

    2012-09-01

    Several studies have used adoptive transfer of purified T cell subsets into immunodeficient mice to determine the subset of T cells responsible for mediating protection against Mycobacterium tuberculosis. These studies suggested that CD62L(hi) memory CD4(+) T cells from BCG-vaccinated mice are key for protection against tuberculosis. Importantly, we observed that transfer of naïve CD4(+) T cells into Rag1-/- recipients protected against a mycobacterial challenge as well as transfer of BCG-experienced CD4(+) T cells. We found that transfer of total CD4(+) T cells from naïve mice or enriched CD62L(hi)CD4(+) T cells from BCG-vaccinated mice into Rag1-/- recipients induced severe colitis by 3 weeks post cell transfer, whereas transfer of CD62L(lo)CD4(+) T cells from BCG-vaccinated mice did not. Naïve and CD62L(hi)CD4(+) T cells proliferated extensively upon transfer and developed an activated effector phenotype in the lung, even in the absence of infectious challenge. The induction of colitis and systemic cytokine response induced by the transfer and subsequent activation of CD4(+) T cells from naïve mice or CD62L(hi)CD4(+) T cells from BCG-vaccinated mice, into immunodeficient recipients, may heighten their ability to protect against mycobacterial challenge. This raises doubts about the validity of this model to study CD4(+) T cell-mediated protection against tuberculosis.

  15. Micronutrient supplementation and T-cell mediated immune responses in patients with tuberculosis in Tanzania

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limited studies exist regarding whether incorporating micronutrient supplements during tuberculosis (TB) treatment may improve cell-mediated immune response. We examine the effect of micronutrient supplementation on lymphocyte proliferation response to mycobacteria or T cell mitogens in a randomize...

  16. An MHC class Ib-restricted CD8+ T cell response to lymphocytic choriomeningitis virus.

    PubMed

    Chen, Lili; Jay, David C; Fairbanks, Jared D; He, Xiao; Jensen, Peter E

    2011-12-15

    Conventional MHC class Ia-restricted CD8(+) T cells play a dominant role in the host response to virus infections, but recent studies indicate that T cells with specificity for nonclassical MHC class Ib molecules may also participate in host defense. To investigate the potential role of class Ib molecules in anti-viral immune responses, K(b-/-)D(b-/-)CIITA(-/-) mice lacking expression of MHC class Ia and class II molecules were infected with lymphocytic choriomeningitis virus (LCMV). These animals have a large class Ib-selected CD8(+) T cell population and they were observed to mediate partial (but incomplete) virus clearance during acute LCMV infection as compared with K(b-/-)D(b-/-)β(2)-microglobulin(-/-) mice that lack expression of both MHC class Ia and class Ib molecules. Infection was associated with expansion of splenic CD8(+) T cells and induction of granzyme B and IFN-γ effector molecules in CD8(+) T cells. Partial virus clearance was dependent on CD8(+) cells. In vitro T cell restimulation assays demonstrated induction of a population of β(2)-microglobulin-dependent, MHC class Ib-restricted CD8(+) T cells with specificity for viral Ags and yet to be defined nonclassical MHC molecules. MHC class Ib-restricted CD8(+) T cell responses were also observed after infection of K(b-/-)D(b-/-)mice despite the low number of CD8(+) T cells in these animals. Long-term infection studies demonstrated chronic infection and gradual depletion of CD8(+) T cells in K(b-/-)D(b-/-)CIITA(-/-) mice, demonstrating that class Ia molecules are required for viral clearance. These findings demonstrate that class Ib-restricted CD8(+) T cells have the potential to participate in the host immune response to LCMV.

  17. Hepatitis C virus strategies to evade the specific-T cell response: a possible mission favoring its persistence.

    PubMed

    Quarleri, Jorge Fabián; Oubiña, José Raúl

    2016-01-01

    Hepatitis C virus (HCV) is a small, enveloped RNA virus. The number of HCV-infected individuals worldwide is estimated to be approximately 200 million. The vast majority of HCV infections persist, with up to 80% of all cases leading to chronic hepatitis associated with liver fibrosis, cirrhosis, and hepatocellular carcinoma. The interaction between HCV and the host have a pivotal role in viral fitness, persistence, pathogenicity, and disease progression. The control of HCV infection requires both effective innate and adaptive immune responses. The HCV clearance during acute infection is associated with an early induction of the innate and a delayed initiation of the adaptive immune responses. However, in the vast majority of acute HCV infections, these responses are overcome and the virus persistence almost inexorably occurs. Recently, several host- and virus-related mechanisms responsible for the failure of both the innate and the adaptive immune responses have been recognized. Among the latter, the wide range of escape mutations to evade the specific-T-and B-cell responses as well as the T cell anergy and the CD8+ T cell exhaustion together with the interference with its function after prolonged virus exposure hold a pivotal role. Other HCV strategies include the modification or manipulation of molecules playing key roles in the induction of the interferon response and its induced effector proteins. In this review, we attempt to gain insights on the main T cell immune evasion strategies used by the virus in order to favor its persistence.

  18. Structural differences in lipomannans from pathogenic and nonpathogenic mycobacteria that impact CD1b-restricted T cell responses.

    PubMed

    Torrelles, Jordi B; Sieling, Peter A; Arcos, Jesús; Knaup, Rose; Bartling, Craig; Rajaram, Murugesan V S; Stenger, Steffen; Modlin, Robert L; Schlesinger, Larry S

    2011-10-14

    Mannosylated molecules on the Mycobacterium tuberculosis surface are important determinants in the immunopathogenesis of tuberculosis. To date, much attention has been paid to mannose-capped lipoarabinomannan, which mediates phagocytosis and intracellular trafficking of M. tuberculosis by engaging the macrophage mannose receptor and subsequently binds to intracellular CD1b molecules for presentation to T cells. Another important mannosylated lipoglycan on the M. tuberculosis surface is lipomannan (LM). Comparative structural detail of the LMs from virulent and avirulent strains is limited as is knowledge regarding their differential capacity to be recognized by the adaptive immune response. Here, we purified LM from the avirulent M. smegmatis and the virulent M. tuberculosis H(37)R(v), performed a comparative structural biochemical analysis, and addressed their ability to stimulate CD1b-restricted T cell clones. We found that M. tuberculosis H(37)R(v) produces a large neutral LM (TB-LM); in contrast, M. smegmatis produces a smaller linear acidic LM (SmegLM) with a high succinate content. Correspondingly, TB-LM was not as efficiently presented to CD1b-restricted T cells as SmegLM. Thus, here we correlate the structure-function relationships for LMs with CD1b-restricted T cell responses and provide evidence that the structural features of TB-LM contribute to its diminished T cell responsiveness.

  19. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    SciTech Connect

    Fogg, Mark; Murphy, John R.; Lorch, Jochen; Posner, Marshall; Wang, Fred

    2013-07-05

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients.

  20. pMHC Multiplexing Strategy to Detect High Numbers of T Cell Responses in Parallel.

    PubMed

    Philips, Daisy; van den Braber, Marlous; Schumacher, Ton N; Kvistborg, Pia

    2017-01-01

    The development of peptide loaded major histocompatibility complexes (MHC) conjugated to fluorochromes by Davis and colleagues 20 years ago provided a highly useful tool to identify and characterize antigen-specific T cells. In this chapter we describe a multiplexing strategy that allows detection of high numbers of T cell responses in parallel.

  1. Tim-3 directly enhances CD8 T cell responses to acute Listeria monocytogenes infection

    PubMed Central

    Gorman, Jacob V.; Starbeck-Miller, Gabriel; Pham, Nhat-Long L.; Traver, Geri L.; Rothman, Paul B.; Harty, John T.; Colgan, John D.

    2014-01-01

    Tim-3 is a surface molecule expressed throughout the immune system that can mediate both stimulatory and inhibitory effects. Previous studies have provided evidence that Tim-3 functions to enforce CD8 T cell exhaustion, a dysfunctional state associated with chronic stimulation. In contrast, the role of Tim-3 in the regulation of CD8 T cell responses to acute and transient stimulation remains undefined. To address this knowledge gap, we examined how Tim-3 affects CD8 T cell responses to acute Listeria monocytogenes (LM) infection. Analysis of wild-type (WT) mice infected with LM revealed that Tim-3 was transiently expressed by activated CD8 T cells and was associated primarily with acquisition of an effector phenotype. Comparison of responses to LM by WT and Tim-3 KO mice showed that the absence of Tim-3 significantly reduced the magnitudes of both primary and secondary CD8 T cell responses, which correlated with decreased IFN-γ production and degranulation by Tim-3 KO cells stimulated with peptide antigen ex vivo. To address the T cell-intrinsic role of Tim-3, we analyzed responses to LM infection by WT and Tim-3 KO TCR-transgenic CD8 T cells following adoptive transfer into a shared WT host. In this setting, the accumulation of CD8 T cells and the generation of cytokine-producing cells were significantly reduced by the lack of Tim-3, demonstrating that this molecule has a direct effect on CD8 T cell function. Combined, our results suggest that Tim-3 can mediate a stimulatory effect on CD8 T cell responses to an acute infection. PMID:24567532

  2. Cross-genotype-specific T-cell responses in acute hepatitis E virus (HEV) infection.

    PubMed

    Gisa, A; Suneetha, P V; Behrendt, P; Pischke, S; Bremer, B; Falk, C S; Manns, M P; Cornberg, M; Wedemeyer, H; Kraft, A R M

    2016-04-01

    Hepatitis E is an inflammatory liver disease caused by infection with the hepatitis E virus (HEV). In tropical regions, HEV is highly endemic and predominantly mediated by HEV genotypes 1 and 2 with >3 million symptomatic cases per year and around 70 000 deaths. In Europe and America, the zoonotic HEV genotypes 3 and 4 have been reported with continues increasing new infections per year. So far, little is known about T-cell responses during acute HEV genotype 3 infection. Therefore, we did a comprehensive study investigating HEV-specific T-cell responses using genotypes 3- and 1-specific overlapping peptides. Additional cytokines and chemokines were measured in the plasma. In four patients, longitudinal studies were performed. Broad functional HEV-specific CD4(+) and CD8(+) T-cell responses were detectable in patients acutely infected with HEV genotype 3. Elevated of pro- and anti-inflammatory cytokine levels during acute HEV infection correlated with ALT levels. Memory HEV-specific T-cell responses were detectable up to >1.5 years upon infection. Importantly, cross-genotype HEV-specific T-cell responses (between genotypes 1 and 3) were measurable in all investigated patients. In conclusion, we could show for the first time HEV-specific T-cell responses during and after acute HEV genotype 3 infection. Our data of cross-genotype HEV-specific T-cell responses might suggest a potential role in cross-genotype-specific protection between HEV genotypes 1 and 3.

  3. Prevalent CD8+ T cell response against one peptide/MHC complex in autoimmune diabetes

    PubMed Central

    Anderson, Brad; Park, Bjung-Ju; Verdaguer, Joan; Amrani, Abdelaziz; Santamaria, Pere

    1999-01-01

    Spontaneous autoimmune diabetes in nonobese diabetic (NOD) mice is the result of a CD4+ and CD8+ T cell-dependent autoimmune process directed against the pancreatic beta cells. CD8+ T cells play a critical role in the initiation and progression of diabetes, but the specificity and diversity of their antigenic repertoire remain unknown. Here, we define the structure of a peptide mimotope that elicits the proliferation, cytokine secretion, differentiation, and cytotoxicity of a diabetogenic H-2Kd-restricted CD8+ T cell specificity (NY8.3) that uses a T cell receptor α (TCRα) rearrangement frequently expressed by CD8+ T cells propagated from the earliest insulitic lesions of NOD mice (Vα17-Jα42 elements, often joined by the N-region sequence M-R-D/E). Stimulation of splenic CD8+ T cells from single-chain 8.3-TCRβ-transgenic NOD mice with this mimotope leads to preferential expansion of T cells bearing an endogenously derived TCRα chain identical to the one used by their islet-associated CD8+ T cells, which is also identical to the 8.3-TCRα sequence. Cytotoxicity assays using islet-derived CD8+ T cell clones from nontransgenic NOD mice as effectors and peptide-pulsed H-2Kd-transfected RMA-S cells as targets indicate that nearly half of the CD8+ T cells recruited to islets in NOD mice specifically recognize the same peptide/H-2Kd complex. This work demonstrates that beta cell-reactive CD8+ T cells mount a prevalent response against a single peptide/MHC complex and provides one peptide ligand for CD8+ T cells in autoimmune diabetes. PMID:10430939

  4. Compensatory T cell responses in IRG-deficient mice prevent sustained Chlamydia trachomatis infections.

    PubMed

    Coers, Jörn; Gondek, Dave C; Olive, Andrew J; Rohlfing, Amy; Taylor, Gregory A; Starnbach, Michael N

    2011-06-01

    The obligate intracellular pathogen Chlamydia trachomatis is the most common cause of bacterial sexually transmitted diseases in the United States. In women C. trachomatis can establish persistent genital infections that lead to pelvic inflammatory disease and sterility. In contrast to natural infections in humans, experimentally induced infections with C. trachomatis in mice are rapidly cleared. The cytokine interferon-γ (IFNγ) plays a critical role in the clearance of C. trachomatis infections in mice. Because IFNγ induces an antimicrobial defense system in mice but not in humans that is composed of a large family of Immunity Related GTPases (IRGs), we questioned whether mice deficient in IRG immunity would develop persistent infections with C. trachomatis as observed in human patients. We found that IRG-deficient Irgm1/m3((-/-)) mice transiently develop high bacterial burden post intrauterine infection, but subsequently clear the infection more efficiently than wildtype mice. We show that the delayed but highly effective clearance of intrauterine C. trachomatis infections in Irgm1/m3((-/-)) mice is dependent on an exacerbated CD4(+) T cell response. These findings indicate that the absence of the predominant murine innate effector mechanism restricting C. trachomatis growth inside epithelial cells results in a compensatory adaptive immune response, which is at least in part driven by CD4(+) T cells and prevents the establishment of a persistent infection in mice.

  5. Broadly targeted CD8+ T cell responses restricted by major histocompatibility complex E

    SciTech Connect

    Hansen, Scott G.; Wu, Helen L.; Burwits, Benjamin J.; Hughes, Colette M.; Hammond, Katherine B.; Ventura, Abigail B.; Reed, Jason S.; Gilbride, Roxanne M.; Ainslie, Emily; Morrow, David W.; Ford, Julia C.; Selseth, Andrea N.; Pathak, Reesab; Malouli, Daniel; Legasse, Alfred W.; Axthelm, Michael K.; Nelson, Jay A.; Gillespie, Geraldine M.; Walters, Lucy C.; Brackenridge, Simon; Sharpe, Hannah R.; Lopez, Cesar Augusto; Fruh, Klaus; Korber, Bette Tina; McMichael, Andrew J.; Gnanakaran, Sandrasegaram; Sacha, Jonah B.; Picker, Louis J.

    2016-02-12

    Major histocompatibility complex (MHC)-E is a highly conserved, ubiquitously expressed, nonclassical, MHC-Ib molecule with limited polymorphism primarily involved in regulation of NK cell reactivity via interaction with NKG2/CD94 receptors. We found that vaccination of rhesus macaques with Rh157.5/.4 gene-deleted rhesus Cytomegalovirus (RhCMV) vectors uniquely diverts MHC-E function to presentation of highly diverse peptide epitopes to CD8α/β+ T cells, approximately 4 distinct epitopes per 100 amino acids, in all tested protein antigens. Computational structural analysis revealed that a relatively stable, open binding groove in MHC-E attains broad peptide binding specificity by imposing a similar backbone configuration on bound peptides with few restrictions based on amino acid side chains. Since MHC-E is up-regulated on cells infected with HIV/SIV and other persistent viruses to evade NK cell activity, MHC-E-restricted CD8+ T cell responses have the potential to exploit pathogen immune evasion adaptations, a capability that might endow these unconventional responses with superior efficacy.

  6. Broadly targeted CD8+ T cell responses restricted by major histocompatibility complex E

    DOE PAGES

    Hansen, Scott G.; Wu, Helen L.; Burwits, Benjamin J.; ...

    2016-02-12

    Major histocompatibility complex (MHC)-E is a highly conserved, ubiquitously expressed, nonclassical, MHC-Ib molecule with limited polymorphism primarily involved in regulation of NK cell reactivity via interaction with NKG2/CD94 receptors. We found that vaccination of rhesus macaques with Rh157.5/.4 gene-deleted rhesus Cytomegalovirus (RhCMV) vectors uniquely diverts MHC-E function to presentation of highly diverse peptide epitopes to CD8α/β+ T cells, approximately 4 distinct epitopes per 100 amino acids, in all tested protein antigens. Computational structural analysis revealed that a relatively stable, open binding groove in MHC-E attains broad peptide binding specificity by imposing a similar backbone configuration on bound peptides with fewmore » restrictions based on amino acid side chains. Since MHC-E is up-regulated on cells infected with HIV/SIV and other persistent viruses to evade NK cell activity, MHC-E-restricted CD8+ T cell responses have the potential to exploit pathogen immune evasion adaptations, a capability that might endow these unconventional responses with superior efficacy.« less

  7. Specific T-cell tolerance may be preceded by a primary response.

    PubMed Central

    Vidard, L; Colarusso, L J; Benacerraf, B

    1994-01-01

    We have evaluated the ability of ovalbumin to induce T-cell-specific tolerance in SJL mice. A significant decrease of interleukin 2 in lymph-node culture supernatants from tolerant mice upon antigen stimulation was seen. Oral tolerization was less effective than i.p.- or s.c.-tolerization protocols. Transfer experiments of either splenic or lymph-node T cells from tolerant mice to naive mice definitely ruled out suppression as a mechanism involved in tolerant mice. Surprisingly, we found that, before the establishment of specific T-cell tolerance to ovalbumin, T cells from mice that will display tolerance were responsive and synthesized interleukin 2 upon antigen challenge in vitro. Thus, we concluded that anergy cannot account solely for the T-cell unresponsiveness in tolerant mice. Furthermore, although we cannot rule out the hypothesis that the T-cell unresponsiveness in tolerant mice can be explained by programmed cell death of ovalbumin-specific T cells, these data led us to speculate that T-cell "refractoriness" could explain the drop of interleukin 2 production in lymph-node T-cell culture supernatant from tolerant mice. PMID:8202538

  8. Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism

    PubMed Central

    Yang, Wei; Bai, Yibing; Xiong, Ying; Zhang, Jin; Chen, Shuokai; Zheng, Xiaojun; Meng, Xiangbo; Li, Lunyi; Wang, Jing; Xu, Chenguang; Yan, Chengsong; Wang, Lijuan; Chang, Catharine C. Y.; Chang, Ta-Yuan; Zhang, Ti; Zhou, Penghui; Song, Bao-Liang; Liu, Wanli; Sun, Shao-cong; Liu, Xiaolong; Li, Bo-liang; Xu, Chenqi

    2016-01-01

    CD8+ T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment1–4. Reactivating the cytotoxicity of CD8+ T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8+ T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme5, led to potentiated effector function and enhanced proliferation of CD8+ but not CD4+ T cells. This is due to the increase in the plasma membrane cholesterol level of CD8+ T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8+ T cells were better than wild-type CD8+ T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile6,7, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy. PMID:26982734

  9. Lenalidomide enhances myeloma-specific T-cell responses in vivo and in vitro

    PubMed Central

    Krämer, Isabelle; Engelhardt, Melanie; Fichtner, Sabrina; Neuber, Brigitte; Medenhoff, Sergej; Bertsch, Uta; Hillengass, Jens; Raab, Marc-Steffen; Hose, Dirk; Ho, Anthony D.; Goldschmidt, Hartmut; Hundemer, Michael

    2016-01-01

    ABSTRACT Immunomodulation is an important part of lenalidomide's mode of action. We analyzed the impact of lenalidomide on T cells from patients with multiple myeloma during lenalidomide therapy in vivo and in patients with lenalidomide-refractory disease in vitro Patients enrolled in the German Speaking Myeloma Multicenter Group (GMMG) MM5 trial received a consolidation therapy with two cycles of lenalidomide after autologous stem cell transplantation (ASCT). Half of the study population continued treatment with lenalidomide maintenance therapy for 2 y, while the other patients received lenalidomide maintenance therapy until complete remission. We analyzed 58 patients with (n = 30) or without (n = 28) lenalidomide therapy and 12 patients refractory to lenalidomide with regards to their anti-myeloma-specific T-cell responses displayed by IFNγ, Granzyme B, and Perforin secretion. The immunophenotype of T-cells was investigated by flow cytometry. Significantly, more myeloma-specific T-cell responses were observed in patients during lenalidomide therapy, compared to patients without treatment. Furthermore, we found on T-cells from patients treated with lenalidomide a decreased CD45RA expression, indicating a maturated immunophenotype and a decreased expression of CD57, indicating functional T cells. An improved myeloma-specific T-cell response was observed in 6 out of 12 heavily pretreated patients (refractory to lenalidomide) after in vitro incubation with lenalidomide. Complementary to the results in vivo, lenalidomide decreased CD45RA expression on T cells in vitro. PMID:27467960

  10. Lenalidomide enhances myeloma-specific T-cell responses in vivo and in vitro.

    PubMed

    Krämer, Isabelle; Engelhardt, Melanie; Fichtner, Sabrina; Neuber, Brigitte; Medenhoff, Sergej; Bertsch, Uta; Hillengass, Jens; Raab, Marc-Steffen; Hose, Dirk; Ho, Anthony D; Goldschmidt, Hartmut; Hundemer, Michael

    2016-05-01

    Immunomodulation is an important part of lenalidomide's mode of action. We analyzed the impact of lenalidomide on T cells from patients with multiple myeloma during lenalidomide therapy in vivo and in patients with lenalidomide-refractory disease in vitro Patients enrolled in the German Speaking Myeloma Multicenter Group (GMMG) MM5 trial received a consolidation therapy with two cycles of lenalidomide after autologous stem cell transplantation (ASCT). Half of the study population continued treatment with lenalidomide maintenance therapy for 2 y, while the other patients received lenalidomide maintenance therapy until complete remission. We analyzed 58 patients with (n = 30) or without (n = 28) lenalidomide therapy and 12 patients refractory to lenalidomide with regards to their anti-myeloma-specific T-cell responses displayed by IFNγ, Granzyme B, and Perforin secretion. The immunophenotype of T-cells was investigated by flow cytometry. Significantly, more myeloma-specific T-cell responses were observed in patients during lenalidomide therapy, compared to patients without treatment. Furthermore, we found on T-cells from patients treated with lenalidomide a decreased CD45RA expression, indicating a maturated immunophenotype and a decreased expression of CD57, indicating functional T cells. An improved myeloma-specific T-cell response was observed in 6 out of 12 heavily pretreated patients (refractory to lenalidomide) after in vitro incubation with lenalidomide. Complementary to the results in vivo, lenalidomide decreased CD45RA expression on T cells in vitro.

  11. Costimulation endows immunotherapeutic CD8 T cells with IL-36-responsiveness during aerobic glycolysis

    PubMed Central

    Tsurutani, Naomi; Mittal, Payal; St Rose, Marie-Clare; Ngoi, Soo Mun; Svedova, Julia; Treadway, Forrest B.; Laubenbacher, Reinhard; Suárez-Ramírez, Jenny E.; Cauley, Linda S.; Adler, Adam J.; Vella, Anthony T.

    2015-01-01

    CD134 and CD137 primed CD8 T cells mount powerful effector responses upon recall, but even without recall these dual costimulated T cells respond to signal 3 cytokines like IL-12. We searched for alternative signal 3 receptor pathways and found the IL-1 family member IL-36R. While IL-36 alone did not stimulate effector CD8 T cells, in combination with IL-12, or more surprisingly IL-2, induced striking and rapid TCR-independent IFN-γ synthesis. To understand how signal 3 responses functioned in dual costimulated T cells we showed that IL-2 induced IL-36R gene expression in a JAK/STAT dependent manner. These data help delineate a sequential stimulation process where IL-2 conditioning must precede IL-36 for IFN-γ synthesis. Importantly, this responsive state was transient, and functioned only in effector T cells capable of aerobic glycolysis. Specifically, as the effector T cells metabolized glucose and consumed O2, they also retained potential to respond through IL-36R. This suggests that T cells use innate receptor pathways like the IL-36R-axis when programmed for aerobic glycolysis. To explore a function for IL-36R in vivo we showed that dual costimulation therapy reduced B16 melanoma tumor growth while increasing IL-36R gene expression. In sum, cytokine therapy to eliminate tumors may target effector T cells, even outside of TCR specificity, as long as the effectors are in the correct metabolic state. PMID:26573834

  12. HIV-specific cytolytic CD4 T cell responses during acute HIV infection predict disease outcome

    PubMed Central

    Soghoian, Damien Z.; Jessen, Heiko; Flanders, Michael; Sierra-Davidson, Kailan; Cutler, Sam; Pertel, Thomas; Ranasinghe, Srinika; Lindqvist, Madelene; Davis, Isaiah; Lane, Kimberly; Rychert, Jenna; Rosenberg, Eric S.; Piechocka-Trocha, Alicja; Brass, Abraham L.; Brenchley, Jason M.; Walker, Bruce D.; Streeck, Hendrik

    2013-01-01

    Early immunological events during acute HIV infection are thought to fundamentally influence long-term disease outcome. Whereas the contribution of HIV-specific CD8 T cell responses to early viral control is well established, the role of HIV-specific CD4 T cell responses in the control of viral replication following acute infection is unknown. A growing body of evidence suggests that CD4 T cells - besides their helper function - have the capacity to directly recognize and kill virally infected cells. In a longitudinal study of a cohort of individuals acutely infected with HIV, we observed that subjects able to spontaneously control HIV replication in the absence of antiretroviral therapy showed a significant expansion of HIV-specific CD4 T cell responses—but not CD8 T cell responses–compared to subjects who progressed to a high viral set point (p=0.038). Strikingly, this expansion occurred prior to differences in viral load or CD4 T cell count and was characterized by robust cytolytic activity and expression of a distinct profile of perforin and granzymes at the earliest time point. Kaplan-Meier analysis revealed that the emergence of Granzyme A+ HIV-specific CD4 T cell responses at baseline was highly predictive of slower disease progression and clinical outcome (average days to CD4 T cell count <350/μl was 575 versus 306, p=0.001). These data demonstrate that HIV-specific CD4 T cell responses can be used during the earliest phase of HIV infection as an immunological predictor of subsequent viral set point and disease outcome. Moreover, these data suggest that expansion of Granzyme A+ HIV-specific cytolytic CD4 T cell responses early during acute HIV infection contributes substantially to the control of viral replication. PMID:22378925

  13. Triggering of toll-like receptor signaling pathways in T cells contributes to the anti-tumor efficacy of T cell responses.

    PubMed

    Salem, Mohamed Labib

    2011-06-30

    Traditionally, expression of toll-like receptors (TLRs) has been associated with innate immune cells in particular professional antigen presenting cells and natural killer cells. This led to the concept that the adjuvant effects of ligation of TLR in a host occur mainly in innate immune cells. However, this concept has been challenged by recent studies including ours demonstrating that T cells express appreciated levels of different TLRs, which can serve as costimulatory co-receptors during polyclonal and antigen-specific stimulation of T cells. Because T cells express low levels of TLRs as compared to innate immune cells, increasing the expression levels of TLRs in T cells can significantly maximize their responses to the costimulatory effects of TLR ligation. This review article focuses on the potential role of TLR expression in T cells in their responses to vaccination regimen containing TLR agonists and how it can be modulated to optimize anti-tumor immunity.

  14. Responses of bovine WC1(+) gammadelta T cells to protein and nonprotein antigens of Mycobacterium bovis.

    PubMed

    Welsh, Michael D; Kennedy, Hilary E; Smyth, Allister J; Girvin, R Martyn; Andersen, Peter; Pollock, John M

    2002-11-01

    WC1(+) gammadelta T cells of Mycobacterium bovis-infected cattle are highly responsive to M. bovis sonic extract (MBSE). In mycobacterial infections of other species, gammadelta T cells have been shown to respond to protein and nonprotein antigens, but the bovine WC1(+) gammadelta T-cell antigenic targets within MBSE require further definition in terms of the dominance of protein versus nonprotein components. The present study sought to characterize the WC1(+) gammadelta T-cell antigenic targets, together with the role of interleukin-2 (IL-2), in the context of M. bovis infection. This was achieved by testing crude and defined antigens to assess protein versus nonprotein recognition by WC1(+) gammadelta T cells in comparison with CD4(+) alphabeta T cells. Both cell types proliferated strongly in response to MBSE, with CD4(+) T cells being the major producers of gamma interferon (IFN-gamma). However, enzymatic digestion of the protein in MBSE removed its ability to stimulate CD4(+) T-cell responses, whereas some WC1(+) gammadelta T-cell proliferation remained. The most antigenic protein inducing proliferation and IFN-gamma secretion in WC1(+) gammadelta T-cell cultures was found to be ESAT-6, which is a potential novel diagnostic reagent and vaccine candidate. In addition, WC1(+) gammadelta T-cell proliferation was observed in response to stimulation with prenyl pyrophosphate antigens (isopentenyl pyrophosphate and monomethyl phosphate). High levels of cellular activation (CD25 expression) resulted from MBSE stimulation of WC1(+) gammadelta T cells from infected animals. A similar degree of activation was induced by IL-2 alone, but for WC1(+) gammadelta T-cell division IL-2 was found to act only as a costimulatory signal, enhancing antigen-driven responses. Overall, the data indicate that protein antigens are important stimulators of WC1(+) gammadelta T-cell proliferation and IFN-gamma secretion in M. bovis infection, with nonprotein antigens inducing significant

  15. Response of γδ T cells to plant-derived tannins

    PubMed Central

    Holderness, Jeff; Hedges, Jodi F.; Daughenbaugh, Katie; Kimmel, Emily; Graff, Jill; Freedman, Brett; Jutila, Mark A.

    2008-01-01

    Many pharmaceutical drugs are isolated from plants used in traditional medicines. Through screening plant extracts, both traditional medicines and compound libraries, new pharmaceutical drugs continue to be identified. Currently, two plant-derived agonists for γδ T cells are described. These plant-derived agonists impart innate effector functions upon distinct γδ T cell subsets. Plant tannins represent one class of γδ T cell agonist and preferentially activate the mucosal population. Mucosal γδ T cells function to modulate tissue immune responses and induce epithelium repair. Select tannins, isolated from apple peel, rapidly induce immune gene transcription in γδ T cells, leading to cytokine production and increased responsiveness to secondary signals. Activity of these tannin preparations tracks to the procyanidin fraction, with the procyanidin trimer (C1) having the most robust activity defined to date. The response to the procyanidins is evolutionarily conserved in that responses are seen with human, bovine, and murine γδ T cells. Procyanidin-induced responses described in this review likely account for the expansion of mucosal γδ T cells seen in mice and rats fed soluble extracts of tannins. Procyanidins may represent a novel approach for treatment of tissue damage, chronic infection, and autoimmune therpies. PMID:19166386

  16. Predicting pathogen-specific CD8 T cell immune responses from a modeling approach.

    PubMed

    Crauste, F; Terry, E; Mercier, I Le; Mafille, J; Djebali, S; Andrieu, T; Mercier, B; Kaneko, G; Arpin, C; Marvel, J; Gandrillon, O

    2015-06-07

    The primary CD8 T cell immune response constitutes a major mechanism to fight an infection by intra-cellular pathogens. We aim at assessing whether pathogen-specific dynamical parameters of the CD8 T cell response can be identified, based on measurements of CD8 T cell counts, using a modeling approach. We generated experimental data consisting in CD8 T cell counts kinetics during the response to three different live intra-cellular pathogens: two viruses (influenza, vaccinia) injected intranasally, and one bacteria (Listeria monocytogenes) injected intravenously. All pathogens harbor the same antigen (NP68), but differ in their interaction with the host. In parallel, we developed a mathematical model describing the evolution of CD8 T cell counts and pathogen amount during an immune response. This model is characterized by 9 parameters and includes relevant feedback controls. The model outputs were compared with the three data series and an exhaustive estimation of the parameter values was performed. By focusing on the ability of the model to fit experimental data and to produce a CD8 T cell population mainly composed of memory cells at the end of the response, critical parameters were identified. We show that a small number of parameters (2-4) define the main features of the CD8 T cell immune response and are characteristic of a given pathogen. Among these parameters, two are related to the effector CD8 T cell mediated control of cell and pathogen death. The parameter associated with memory cell death is shown to play no relevant role during the main phases of the CD8 T cell response, yet it becomes essential when looking at the predictions of the model several months after the infection.

  17. Lamivudine treatment can restore T cell responsiveness in chronic hepatitis B.

    PubMed Central

    Boni, C; Bertoletti, A; Penna, A; Cavalli, A; Pilli, M; Urbani, S; Scognamiglio, P; Boehme, R; Panebianco, R; Fiaccadori, F; Ferrari, C

    1998-01-01

    High viral and/or antigen load may be an important cause of the T cell hyporesponsiveness to hepatitis B virus (HBV) antigens that is often observed in patients with chronic HBV infection. Reduction of viral and antigen load by lamivudine treatment represents an ideal model for investigating this hypothesis. HLA class II restricted T cell responses and serum levels of HBV-DNA, HBsAg, and HBeAg were studied before and during lamivudine treatment in 12 patients with hepatitis B e antigen positive chronic active hepatitis B to assess possible correlations between viral and/or antigen load and vigor of the T cell response. Cell proliferation to HBV nucleocapsid antigens and peptides and frequency of circulating HBV nucleocapsid-specific T cells were assessed to characterize CD4-mediated responses. A highly significant enhancement of the CD4-mediated response to HBV nucleocapsid antigens was already detectable in most patients 7-14 d after the start of lamivudine treatment. This effect was dramatic and persistent in 10 patients but undetectable in 2. It occurred concomitant with a rapid and marked reduction of viremia. Interestingly, lamivudine also enhanced the responses to mitogens and recall antigens, showing that its effect was not limited to HBV-specific T cells. In conclusion, an efficient antiviral T cell response can be restored by lamivudine treatment in patients with chronic hepatitis B concurrently with reduction of viremia, indicating the importance of viral load in the pathogenesis of T cell hyporesponsiveness in these patients. Since lamivudine treatment can overcome T cell hyporeactivity, combining lamivudine with treatments directed to stimulate the T cell response may represent an effective strategy to induce eradication of chronic HBV infection. PMID:9727065

  18. Receptor Pre-Clustering and T cell Responses: Insights into Molecular Mechanisms.

    PubMed

    Castro, Mario; van Santen, Hisse M; Férez, María; Alarcón, Balbino; Lythe, Grant; Molina-París, Carmen

    2014-01-01

    T cell activation, initiated by T cell receptor (TCR) mediated recognition of pathogen-derived peptides presented by major histocompatibility complex class I or II molecules (pMHC), shows exquisite specificity and sensitivity, even though the TCR-pMHC binding interaction is of low affinity. Recent experimental work suggests that TCR pre-clustering may be a mechanism via which T cells can achieve such high sensitivity. The unresolved stoichiometry of the TCR makes TCR-pMHC binding and TCR triggering, an open question. We formulate a mathematical model to characterize the pre-clustering of T cell receptors (TCRs) on the surface of T cells, motivated by the experimentally observed distribution of TCR clusters on the surface of naive and memory T cells. We extend a recently introduced stochastic criterion to compute the timescales of T cell responses, assuming that ligand-induced cross-linked TCR is the minimum signaling unit. We derive an approximate formula for the mean time to signal initiation. Our results show that pre-clustering reduces the mean activation time. However, additional mechanisms favoring the existence of clusters are required to explain the difference between naive and memory T cell responses. We discuss the biological implications of our results, and both the compatibility and complementarity of our approach with other existing mathematical models.

  19. Receptor Pre-Clustering and T cell Responses: Insights into Molecular Mechanisms

    PubMed Central

    Castro, Mario; van Santen, Hisse M.; Férez, María; Alarcón, Balbino; Lythe, Grant; Molina-París, Carmen

    2014-01-01

    T cell activation, initiated by T cell receptor (TCR) mediated recognition of pathogen-derived peptides presented by major histocompatibility complex class I or II molecules (pMHC), shows exquisite specificity and sensitivity, even though the TCR–pMHC binding interaction is of low affinity. Recent experimental work suggests that TCR pre-clustering may be a mechanism via which T cells can achieve such high sensitivity. The unresolved stoichiometry of the TCR makes TCR–pMHC binding and TCR triggering, an open question. We formulate a mathematical model to characterize the pre-clustering of T cell receptors (TCRs) on the surface of T cells, motivated by the experimentally observed distribution of TCR clusters on the surface of naive and memory T cells. We extend a recently introduced stochastic criterion to compute the timescales of T cell responses, assuming that ligand-induced cross-linked TCR is the minimum signaling unit. We derive an approximate formula for the mean time to signal initiation. Our results show that pre-clustering reduces the mean activation time. However, additional mechanisms favoring the existence of clusters are required to explain the difference between naive and memory T cell responses. We discuss the biological implications of our results, and both the compatibility and complementarity of our approach with other existing mathematical models. PMID:24817867

  20. Multifunctional T-cell Analyses to Study Response and Progression in Adoptive Cell Transfer Immunotherapy

    PubMed Central

    Ma, Chao; Cheung, Ann F.; Chodon, Thinle; Koya, Richard C.; Wu, Zhongqi; Ng, Charles; Avramis, Earl; Cochran, Alistair J.; Witte, Owen N.; Baltimore, David; Chmielowski, Bartosz; Economou, James S.; Comin-Anduix, Begonya; Ribas, Antoni; Heath, James R.

    2013-01-01

    Adoptive cell transfer (ACT) of genetically engineered T cells expressing cancer-specific T-cell receptors (TCR) is a promising cancer treatment. Here, we investigate the in vivo functional activity and dynamics of the transferred cells by analyzing samples from 3 representative patients with melanoma enrolled in a clinical trial of ACT with TCR transgenic T cells targeted against the melanosomal antigen MART-1. The analyses included evaluating 19 secreted proteins from individual cells from phenotypically defined T-cell subpopulations, as well as the enumeration of T cells with TCR antigen specificity for 36 melanoma antigens. These analyses revealed the coordinated functional dynamics of the adoptively transferred, as well as endogenous, T cells, and the importance of highly functional T cells in dominating the antitumor immune response. This study highlights the need to develop approaches to maintaining antitumor T-cell functionality with the aim of increasing the long-term efficacy of TCR-engineered ACT immunotherapy. SIGNIFICANCE A longitudinal functional study of adoptively transferred TCR–engineered lymphocytes yielded revealing snapshots for understanding the changes of antitumor responses over time in ACT immunotherapy of patients with advanced melanoma. PMID:23519018

  1. MOLECULAR MECHANISMS FOR ADAPTIVE TOLERANCE AND OTHER T CELL ANERGY MODELS

    PubMed Central

    Choi, Seeyoung; Schwartz, Ronald H.

    2007-01-01

    Since the original description of T cell anergy in CD4 clones from mice and humans, a number of different unresponsive states have been described, both in vivo and in vitro, that have been called anergic. While initial attempts were made to understand the similarities between the different models, it has now become clear from biochemical experiments that many of them have different molecular mechanisms underlying their unresponsiveness. In this review we will detail our own work on the in vivo model referred to as adaptive tolerance and then attempt to compare this biochemical state to the multitude of other states that have been described in the literature. PMID:17400472

  2. Intravaginal immunization with HPV vectors induces tissue-resident CD8+ T cell responses

    PubMed Central

    Çuburu, Nicolas; Graham, Barney S.; Buck, Christopher B.; Kines, Rhonda C.; Pang, Yuk-Ying S.; Day, Patricia M.; Lowy, Douglas R.; Schiller, John T.

    2012-01-01

    The induction of persistent intraepithelial CD8+ T cell responses may be key to the development of vaccines against mucosally transmitted pathogens, particularly for sexually transmitted diseases. Here we investigated CD8+ T cell responses in the female mouse cervicovaginal mucosa after intravaginal immunization with human papillomavirus vectors (HPV pseudoviruses) that transiently expressed a model antigen, respiratory syncytial virus (RSV) M/M2, in cervicovaginal keratinocytes. An HPV intravaginal prime/boost with different HPV serotypes induced 10-fold more cervicovaginal antigen-specific CD8+ T cells than priming alone. Antigen-specific T cell numbers decreased only 2-fold after 6 months. Most genital antigen-specific CD8+ T cells were intra- or subepithelial, expressed αE-integrin CD103, produced IFN-γ and TNF-α, and displayed in vivo cytotoxicity. Using a sphingosine-1-phosphate analog (FTY720), we found that the primed CD8+ T cells proliferated in the cervicovaginal mucosa upon HPV intravaginal boost. Intravaginal HPV prime/boost reduced cervicovaginal viral titers 1,000-fold after intravaginal challenge with vaccinia virus expressing the CD8 epitope M2. In contrast, intramuscular prime/boost with an adenovirus type 5 vector induced a higher level of systemic CD8+ T cells but failed to induce intraepithelial CD103+CD8+ T cells or protect against recombinant vaccinia vaginal challenge. Thus, HPV vectors are attractive gene-delivery platforms for inducing durable intraepithelial cervicovaginal CD8+ T cell responses by promoting local proliferation and retention of primed antigen-specific CD8+ T cells. PMID:23143305

  3. Ly6Chi monocytes regulate T cell responses in viral hepatitis

    PubMed Central

    Zhu, Jiangao; Chen, Huiyao; Huang, Xiaopei; Jiang, Songfu

    2016-01-01

    Viral hepatitis remains a global health challenge despite recent progress in the development of more effective therapies. Although virus-specific CD8+ and CD4+ T cell responses are essential for viral clearance, it remains largely unknown what regulates T cell–mediated viral clearance. Thus, a better understanding of the regulation of anti-viral T cell immunity would be critical for the design of more effective therapies for viral hepatitis. Using a model of adenovirus-induced hepatitis, here we showed that adenoviral infection induced recruitment of Ly6Chi monocytes to the liver in a CCR2-dependent manner. These recruited Ly6Chi monocytes suppressed CD8+ and CD4+ T cell responses to adenoviral infection, leading to a delay in viral clearance. In vivo depletion of Ly6Chi monocytes markedly enhanced anti-viral T cell responses and promoted viral clearance. Mechanistically, we showed that induction of iNOS and the production of NO by Ly6Chi monocytes are critical for the suppression of T cell responses. In addition, a contact-dependent mechanism mediated by PD-1 and PD-L1 interaction is also required for T cell suppression by Ly6Chi monocytes. These findings suggest a critical role for Ly6Chi monocytes in the regulation of T cell immunity in viral hepatitis and may provide new insights into development of more effective therapies for treating viral hepatitis based on targeting the immunosuppressing monocytes. PMID:27777980

  4. Private specificities of CD8 T cell responses control patterns of heterologous immunity

    PubMed Central

    Kim, Sung-Kwon; Cornberg, Markus; Wang, Xiaoting Z.; Chen, Hong D.; Selin, Liisa K.; Welsh, Raymond M.

    2005-01-01

    CD8 T cell cross-reactivity between viruses can play roles in protective heterologous immunity and damaging immunopathology. This cross-reactivity is sometimes predictable, such as between lymphocytic choriomeningitis virus (LCMV) and Pichinde virus, where cross-reactive epitopes share six out of eight amino acids. Here, however, we demonstrate more subtle and less predictable cross-reactivity between LCMV and the unrelated vaccinia virus (VV). Epitope-specific T cell receptor usage differed between individual LCMV-infected C57BL/6 mice, even though the mice had similar epitope-specific T cell hierarchies. LCMV-immune mice challenged with VV showed variations, albeit in a distinct hierarchy, in proliferative expansions of and down-regulation of IL-7Rα by T cells specific to different LCMV epitopes. T cell responses to a VV-encoded epitope that is cross-reactive with LCMV fluctuated greatly in VV-infected LCMV-immune mice. Adoptive transfers of splenocytes from individual LCMV-immune donors resulted in nearly identical VV-induced responses in each of several recipients, but responses differed depending on the donor. This indicates that the specificities of T cell responses that are not shared between individuals may influence cross-reactivity with other antigens and play roles in heterologous immunity upon encounter with another pathogen. This variability in cross-reactive T cell expansion that is unique to the individual may underlie variation in the pathogenesis of infectious diseases. PMID:15710651

  5. Lipopolysaccharides with acylation defects potentiate TLR4 signaling and shape T cell responses.

    PubMed

    Martirosyan, Anna; Ohne, Yoichiro; Degos, Clara; Gorvel, Laurent; Moriyón, Ignacio; Oh, Sangkon; Gorvel, Jean-Pierre

    2013-01-01

    Lipopolysaccharides or endotoxins are components of Gram-negative enterobacteria that cause septic shock in mammals. However, a LPS carrying hexa-acyl lipid A moieties is highly endotoxic compared to a tetra-acyl LPS and the latter has been considered as an antagonist of hexa-acyl LPS-mediated TLR4 signaling. We investigated the relationship between the structure and the function of bacterial LPS in the context of human and mouse dendritic cell activation. Strikingly, LPS with acylation defects were capable of triggering a strong and early TLR4-dependent DC activation, which in turn led to the activation of the proteasome machinery dampening the pro-inflammatory cytokine secretion. Upon activation with tetra-acyl LPS both mouse and human dendritic cells triggered CD4(+) T and CD8(+) T cell responses and, importantly, human myeloid dendritic cells favored the induction of regulatory T cells. Altogether, our data suggest that LPS acylation controlled by pathogenic bacteria might be an important strategy to subvert adaptive immunity.

  6. Characteristics of HLA-E Restricted T-Cell Responses and Their Role in Infectious Diseases

    PubMed Central

    Ottenhoff, Tom H. M.

    2016-01-01

    Human HLA-E can, in addition to self-antigens, also present pathogen-derived sequences, which elicit specific T-cell responses. T-cells recognize their antigen presented by HLA-E highly specifically and have unique functional and phenotypical properties. Pathogen specific HLA-E restricted CD8+ T-cells are an interesting new player in the field of immunology. Future work should address their exact roles and relative contributions in the immune response against infectious diseases. PMID:27699181

  7. Long-lasting memory T cell responses following self-limited acute hepatitis B.

    PubMed Central

    Penna, A; Artini, M; Cavalli, A; Levrero, M; Bertoletti, A; Pilli, M; Chisari, F V; Rehermann, B; Del Prete, G; Fiaccadori, F; Ferrari, C

    1996-01-01

    The molecular and cellular basis of long-term T cell memory against viral antigens is still largely undefined. To characterize anti-viral protection by memory T cells against non-cytopathic viruses able to cause acute self-limited and chronic infections, such as the hepatitis B virus (HBV), we studied HLA class II restricted responses against HBV structural antigens in 17 patients with acute hepatitis B, during the acute stage of infection and 2.2 to 13 yr after clinical resolution of disease. Results indicate that: (a) significant T cell proliferative responses to HBV nucleocapsid antigens were detectable in all patients during the acute phase of infection and in 14/17 also 2-13 yr after clinical resolution of disease; b) long-lasting T cell responses were sustained by CD45RO+T cells, predominantly expressing the phenotype of recently activated cells; c) limiting dilution analysis showed that in some patients the frequency of HBV-specific T cells was comparable to that observed in the acute stage of infection and, usually, higher than in patients with chronic HBV infection; d) the same amino acid sequences were recognized by T cells in the acute and recovery phases of infection; and e) HBV-DNA was detectable by nested-PCR in approximately half of the subjects. to conclusion, our results show that vigorous anti-viral T cell responses are detectable in vitro several years after clinical recovery from acute hepatitis B. Detection of minute amounts of virus in some recovered subjects suggests that long-term maintenance of an active anti-viral T cell response could be important not only for protection against reinfection but also for keeping the persisting virus under tight control. PMID:8787682

  8. CD25+ natural regulatory T cells are critical in limiting innate and adaptive immunity and resolving disease following respiratory syncytial virus infection.

    PubMed

    Lee, Debbie C P; Harker, James A E; Tregoning, John S; Atabani, Sowsan F; Johansson, Cecilia; Schwarze, Jürgen; Openshaw, Peter J M

    2010-09-01

    Regulatory CD4(+) T cells have been shown to be important in limiting immune responses, but their role in respiratory viral infections has received little attention. Here we observed that following respiratory syncytial virus (RSV) infection, CD4(+) Foxp3(+) CD25(+) natural regulatory T-cell numbers increased in the bronchoalveolar lavage fluid, lung, mediastinal lymph nodes, and spleen. The depletion of CD25(+) natural regulatory T cells prior to RSV infection led to enhanced weight loss with delayed recovery that was surprisingly accompanied by increased numbers of activated natural killer cells in the lung and bronchoalveolar lavage fluid on day 8 postinfection. Increased numbers of neutrophils were also detected within the bronchoalveolar lavage fluid and correlated with elevated levels of myeloperoxidase as well as interleukin-6 (IL-6) and gamma interferon (IFN-gamma). CD25(+) natural regulatory T-cell depletion also led to enhanced numbers of proinflammatory T cells producing IFN-gamma and tumor necrosis factor alpha (TNF-alpha) in the lung. Despite these increases in inflammatory responses and disease severity, the viral load was unaltered. This work highlights a critical role for natural regulatory T cells in regulating the adaptive and innate immune responses during the later stages of lung viral infections.

  9. T cell responses to human platelet antigen–1a involve a unique form of indirect allorecognition

    PubMed Central

    Ahlen, Maria Therese; Husebekk, Anne; Killie, Ida Løken; Skogen, Bjørn

    2016-01-01

    Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a pregnancy-related condition caused by maternal antibodies binding an alloantigen on fetal platelets. In most cases the alloantigen is formed by a single amino acid, integrin β3 Leu33, referred to as human platelet antigen–1a (HPA-1a). Production of anti–HPA-1a antibodies likely depends on CD4+ T cells that recognize the same alloantigen in complex with the HLA-DRA/DRB3*01:01 molecule. While this complex is well characterized, T cell recognition of it is not. Here, to examine the nature of antigen recognition by HPA-1a–specific T cells, we assayed native and synthetic variants of the integrin β3 peptide antigen for binding to DRA/DRB3*01:01-positive antigen-presenting cells and for T cell activation. We found that HPA-1a–specific T cells recognize non-allogeneic integrin β3 residues anchored to DRA/DRB3*01:01 by the allogeneic Leu33, which itself is not directly recognized by these T cells. Furthermore, these T cell responses are diverse, with different T cells depending on different residues for recognition. This represents a unique form of indirect allorecognition in which a non-allogeneic peptide sequence becomes immunogenic by stable anchoring to MHC by an allogeneic residue. PMID:27699233

  10. Antiparasitic Treatment Induces an Improved CD8(+) T Cell Response in Chronic Chagasic Patients.

    PubMed

    Mateus, Jose; Pérez-Antón, Elena; Lasso, Paola; Egui, Adriana; Roa, Nubia; Carrilero, Bartolomé; González, John M; Thomas, M Carmen; Puerta, Concepción J; López, Manuel C; Cuéllar, Adriana

    2017-04-15

    Chagas disease is a chronic infection caused by Trypanosoma cruzi, an intracellular protozoan parasite. Chronic chagasic patients (CCPs) have dysfunctional CD8(+) T cells that are characterized by impaired cytokine production, high coexpression of inhibitory receptors, and advanced cellular differentiation. Most patients diagnosed in the chronic phase of Chagas disease already exhibit heart involvement, and there is no vaccination that protects against the disease. Antiparasitic treatment is controversial as to its indication for this stage of the disease. There is a lack of biological markers to evaluate the effectiveness of antiparasitic treatment, and little is known about the effect of the treatment on CD8(+) T cells. Thus, the aim of the current study was to analyze the early effects of antiparasitic treatment on CD8(+) T cells from CCPs with asymptomatic clinical forms of disease. To evaluate the CD8(+) T cell subsets, expression of inhibitory receptors, and functionality of T cells in CCPs, PBMCs were isolated. The results showed that treatment of CCPs with the asymptomatic form of the disease induces an increase in the frequency of CD8(+) central memory T cells and terminal effector T cells, a decrease in the coexpression of inhibitory receptors, an improved Ag-specific CD8(+) T cell response exhibited by the individual production of IFN-γ or IL-2, and a multifunctional CD8(+) T cell profile of up to four functions (IFN-γ(+)IL-2(+)Perforin(+)Granzyme B(+)). These findings suggest that, in CCPs, antiparasitic treatment improved the quality of Ag-specific CD8(+) T cell responses associated with a decrease in inhibitory receptor coexpression, which could serve as biomarkers for monitoring the effectiveness of antiparasitic treatment.

  11. T cell Bim levels reflect responses to anti–PD-1 cancer therapy

    PubMed Central

    Dronca, Roxana S.; Liu, Xin; Harrington, Susan M.; Chen, Lingling; Cao, Siyu; Kottschade, Lisa A.; McWilliams, Robert R.; Block, Matthew S.; Nevala, Wendy K.; Thompson, Michael A.; Mansfield, Aaron S.; Park, Sean S.; Markovic, Svetomir N.

    2016-01-01

    Immune checkpoint therapy with PD-1 blockade has emerged as an effective therapy for many advanced cancers; however, only a small fraction of patients achieve durable responses. To date, there is no validated blood-based means of predicting the response to PD-1 blockade. We report that Bim is a downstream signaling molecule of the PD-1 pathway, and its detection in T cells is significantly associated with expression of PD-1 and effector T cell markers. High levels of Bim in circulating tumor-reactive (PD-1+CD11ahiCD8+) T cells were prognostic of poor survival in patients with metastatic melanoma who did not receive anti–PD-1 therapy and were also predictive of clinical benefit in patients with metastatic melanoma who were treated with anti–PD-1 therapy. Moreover, this circulating tumor-reactive T cell population significantly decreased after successful anti–PD-1 therapy. Our study supports a crucial role of Bim in both T cell activation and apoptosis as regulated by PD-1 and PD-L1 interactions in effector CD8+ T cells. Measurement of Bim levels in circulating T cells of patients with cancer may provide a less invasive strategy to predict and monitor responses to anti–PD-1 therapy, although future prospective analyses are needed to validate its utility. PMID:27182556

  12. Immune-checkpoint proteins VISTA and PD-1 nonredundantly regulate murine T-cell responses.

    PubMed

    Liu, Jun; Yuan, Ying; Chen, Wenna; Putra, Juan; Suriawinata, Arief A; Schenk, Austin D; Miller, Halli E; Guleria, Indira; Barth, Richard J; Huang, Yina H; Wang, Li

    2015-05-26

    V-domain immunoglobulin suppressor of T-cell activation (VISTA) is a negative immune-checkpoint protein that suppresses T-cell responses. To determine whether VISTA synergizes with another immune-checkpoint, programmed death 1 (PD-1), this study characterizes the immune responses in VISTA-deficient, PD-1-deficient (KO) mice and VISTA/PD-1 double KO mice. Chronic inflammation and spontaneous activation of T cells were observed in both single KO mice, demonstrating their nonredundancy. However, the VISTA/PD-1 double KO mice exhibited significantly higher levels of these phenotypes than the single KO mice. When bred onto the 2D2 T-cell receptor transgenic mice, which are predisposed to development of inflammatory autoimmune disease in the CNS, the level of disease penetrance was significantly enhanced in the double KO mice compared with in the single KO mice. Consistently, the magnitude of T-cell response toward foreign antigens was synergistically higher in the VISTA/PD-1 double KO mice. A combinatorial blockade using monoclonal antibodies specific for VISTA and PD-L1 achieved optimal tumor-clearing therapeutic efficacy. In conclusion, our study demonstrates the nonredundant role of VISTA that is distinct from the PD-1/PD-L1 pathway in controlling T-cell activation. These findings provide the rationale to concurrently target VISTA and PD-1 pathways for treating T-cell-regulated diseases such as cancer.

  13. Impaired T-cell responses to sphingosine-1-phosphate in HIV-1 infected lymph nodes

    PubMed Central

    Mudd, Joseph C.; Murphy, Patrick; Manion, Maura; Debernardo, Robert; Hardacre, Jeffrey; Ammori, John; Hardy, Gareth A.; Harding, Clifford V.; Mahabaleshwar, Ganapati H.; Jain, Mukesh K.; Jacobson, Jeffrey M.; Brooks, Ari D.; Lewis, Sharon; Schacker, Timothy W.; Anderson, Jodi; Haddad, Elias K.; Cubas, Rafael A.; Rodriguez, Benigno; Sieg, Scott F.

    2013-01-01

    The determinants of HIV-1-associated lymphadenopathy are poorly understood. We hypothesized that lymphocytes could be sequestered in the HIV-1+ lymph node (LN) through impairments in sphingosine-1-phosphate (S1P) responsiveness. To test this hypothesis, we developed novel assays for S1P-induced Akt phosphorylation and actin polymerization. In the HIV-1+ LN, naïve CD4 T cells and central memory CD4 and CD8 T cells had impaired Akt phosphorylation in response to S1P, whereas actin polymerization responses to S1P were impaired dramatically in all LN maturation subsets. These defects were improved with antiretroviral therapy. LN T cells expressing CD69 were unable to respond to S1P in either assay, yet impaired S1P responses were also seen in HIV-1+ LN T cells lacking CD69 expression. Microbial elements, HIV-1, and interferon α – putative drivers of HIV-1associated immune activation all tended to increase CD69 expression and reduce T-cell responses to S1P in vitro. Impairment in T-cell egress from lymph nodes through decreased S1P responsiveness may contribute to HIV-1-associated LN enlargement and to immune dysregulation in a key organ of immune homeostasis. PMID:23422746

  14. CD8+ T Cell Exhaustion, Suppressed Gamma Interferon Production, and Delayed Memory Response Induced by Chronic Brucella melitensis Infection

    PubMed Central

    Durward-Diioia, Marina; Harms, Jerome; Khan, Mike; Hall, Cherisse; Smith, Judith A.

    2015-01-01

    Brucella melitensis is a well-adapted zoonotic pathogen considered a scourge of mankind since recorded history. In some cases, initial infection leads to chronic and reactivating brucellosis, incurring significant morbidity and economic loss. The mechanism by which B. melitensis subverts adaptive immunological memory is poorly understood. Previous work has shown that Brucella-specific CD8+ T cells express gamma interferon (IFN-γ) and can transition to long-lived memory cells but are not polyfunctional. In this study, chronic infection of mice with B. melitensis led to CD8+ T cell exhaustion, manifested by programmed cell death 1 (PD-1) and lymphocyte activation gene 3 (LAG-3) expression and a lack of IFN-γ production. The B. melitensis-specific CD8+ T cells that produced IFN-γ expressed less IFN-γ per cell than did CD8+ cells from uninfected mice. Both memory precursor (CD8+ LFA1HI CD127HI KLRG1LO) and long-lived memory (CD8+ CD27HI CD127HI KLRG1LO) cells were identified during chronic infection. Interestingly, after adoptive transfer, mice receiving cells from chronically infected animals were able to contain infection more rapidly than recipients of cells from acutely infected or uninfected donors, although the proportions of exhausted CD8+ T cells increased after adoptive transfer in both challenged and unchallenged recipients. CD8+ T cells of challenged recipients initially retained the stunted IFN-γ production found prior to transfer, and cells from acutely infected mice were never seen to transition to either memory subset at all time points tested, up to 30 days post-primary infection, suggesting a delay in the generation of memory. Here we have identified defects in Brucella-responsive CD8+ T cells that allow chronic persistence of infection. PMID:26416901

  15. GROUP 2 INNATE LYMPHOID CELLS AND CD4+ T CELLS COOPERATE TO MEDIATE TYPE 2 IMMUNE RESPONSE IN MICE

    PubMed Central

    Drake, Li Yin; Iijima, Koji; Kita, Hirohito

    2014-01-01

    Background Innate lymphoid cells (ILCs) play important roles in innate immunity and tissue remodeling via production of various cytokines and growth factors. Group 2 ILCs (ILC2s) were recently shown to mediate the immune pathology of asthma even without adaptive immunity. However, little is known about possible interactions between ILC2s and other immune cells. We sought to investigate the capacity of ILC2s to regulate effector functions of T cells. Methods We isolated ILC2s from the lungs of naïve mice. We cultured CD4+ T cells with ILC2s in vitro and examined the functions of these cell types. The mechanisms were investigated by using blocking antibodies and cells isolated from cytokine-deficient mice. For the in vivo study, we adoptively transferred ILC2s and CD4+ T cells into Il7ra−/− mice and subsequently exposed the mice to ovalbumin and a cysteine protease. Results Lung ILC2s enhanced CD4+ T cell proliferation and promoted production of type 2 cytokines in vitro. The interaction between ILC2s and CD4+ T cells involved costimulatory molecule OX40L and cytokine IL-4, which was mainly derived from ILC2s. Adoptive transfer of both ILC2 and CD4+ T cell populations, but not each population alone, into Il7ra−/− mice resulted in induction of a robust antigen-specific type 2 cytokine response and airway inflammation. Conclusion Lung ILC2s function to promote adaptive immunity in addition to their established roles in innate immunity. This novel function of ILC2s needs to be taken into account when considering the pathophysiology of asthma and other allergic airway diseases. PMID:24939388

  16. CD8+ T cell exhaustion, suppressed gamma interferon production, and delayed memory response induced by chronic Brucella melitensis infection.

    PubMed

    Durward-Diioia, Marina; Harms, Jerome; Khan, Mike; Hall, Cherisse; Smith, Judith A; Splitter, Gary A

    2015-12-01

    Brucella melitensis is a well-adapted zoonotic pathogen considered a scourge of mankind since recorded history. In some cases, initial infection leads to chronic and reactivating brucellosis, incurring significant morbidity and economic loss. The mechanism by which B. melitensis subverts adaptive immunological memory is poorly understood. Previous work has shown that Brucella-specific CD8(+) T cells express gamma interferon (IFN-γ) and can transition to long-lived memory cells but are not polyfunctional. In this study, chronic infection of mice with B. melitensis led to CD8(+) T cell exhaustion, manifested by programmed cell death 1 (PD-1) and lymphocyte activation gene 3 (LAG-3) expression and a lack of IFN-γ production. The B. melitensis-specific CD8(+) T cells that produced IFN-γ expressed less IFN-γ per cell than did CD8(+) cells from uninfected mice. Both memory precursor (CD8(+) LFA1(HI) CD127(HI) KLRG1(LO)) and long-lived memory (CD8(+) CD27(HI) CD127(HI) KLRG1(LO)) cells were identified during chronic infection. Interestingly, after adoptive transfer, mice receiving cells from chronically infected animals were able to contain infection more rapidly than recipients of cells from acutely infected or uninfected donors, although the proportions of exhausted CD8(+) T cells increased after adoptive transfer in both challenged and unchallenged recipients. CD8(+) T cells of challenged recipients initially retained the stunted IFN-γ production found prior to transfer, and cells from acutely infected mice were never seen to transition to either memory subset at all time points tested, up to 30 days post-primary infection, suggesting a delay in the generation of memory. Here we have identified defects in Brucella-responsive CD8(+) T cells that allow chronic persistence of infection.

  17. Monocytic myeloid-derived suppressor cells regulate T-cell responses against vaccinia virus.

    PubMed

    Fortin, Carl; Yang, Yiping; Huang, Xiaopei

    2017-04-06

    Vaccinia virus (VV) can potently activate NK- and T-cell responses, leading to efficient viral control and generation of long-lasting protective immunity. However, immune responses against viral infections are often tightly controlled to avoid collateral damage and systemic inflammation. We have previously shown that granulocytic myeloid derived suppressor cells (g-MDSCs) can suppress the NK-cell response to VV infection. It remains unknown what regulates T-cell responses to VV infection in vivo. In this study, we first showed that monocytic MDSCs (m-MDSCs), but not g-MDSCs, from VV-infected mice could directly suppress CD4(+) and CD8(+) T-cell activation in vitro. We then demonstrated that defective recruitment of m-MDSCs to the site of VV infection in CCR2(-/-) mice enhanced VV-specific CD8(+) T-cell response and that adoptive transfer of m-MDSCs into VV-infected mice suppressed VV-specific CD8(+) T-cell activation, leading to a delay in viral clearance. Mechanistically, we further showed that T-cell suppression by m-MDSCs is mediated by indication of iNOS and production of NO upon VV infection, and that IFN-γ is required for activation of m-MDSCs. Collectively, our results highlight a critical role for m-MDSCs in regulating T-cell responses against VV infection and may suggest potential strategies using m-MDSCs to modulate T-cell responses during viral infections. This article is protected by copyright. All rights reserved.

  18. Quantifying susceptibility of CD4+ stem memory T-cells to infection by laboratory adapted and clinical HIV-1 strains.

    PubMed

    Flynn, Jacqueline K; Paukovics, Geza; Cashin, Kieran; Borm, Katharina; Ellett, Anne; Roche, Michael; Jakobsen, Martin R; Churchill, Melissa J; Gorry, Paul R

    2014-02-10

    CD4+ T cells are principal targets for human immunodeficiency virus type 1 (HIV-1) infection. CD4+ T cell subsets are heterogeneous cell populations, divided by functional and phenotypic differences into naïve and memory T cells. The memory CD4+ T cells are further segregated into central, effector and transitional memory cell subsets by functional, phenotypic and homeostatic characteristics. Defining the distribution of HIV-1 infection in different T cell subsets is important, as this can play a role in determining the size and composition of the viral reservoir. Both central memory and transitional memory CD4+ T cells have been described as long-lived viral reservoirs for HIV. Recently, the newly described stem memory T cell subset has also been implicated as a long-lived HIV reservoir. Using green fluorescent protein (GFP) reporter strains of HIV-1 and multi parameter flow cytometry, we developed an assay to simultaneously quantify the susceptibility of stem memory (TSCM), central memory, effector memory, transitional memory and naïve CD4+ T cell subsets, to HIV-1 infection in vitro. We show that TSCM are susceptible to infection with laboratory adapted and clinical HIV-1 strains. Our system facilitates the quantitation of HIV-1 infection in alternative T cell subsets by CCR5- and CXCR4-using viruses across different HIV-1 subtypes, and will be useful for studies of HIV-1 pathogenesis and viral reservoirs.

  19. Quantifying Susceptibility of CD4+ Stem Memory T-Cells to Infection by Laboratory Adapted and Clinical HIV-1 Strains

    PubMed Central

    Flynn, Jacqueline K.; Paukovics, Geza; Cashin, Kieran; Borm, Katharina; Ellett, Anne; Roche, Michael; Jakobsen, Martin R.; Churchill, Melissa J.; Gorry, Paul R.

    2014-01-01

    CD4+ T cells are principal targets for human immunodeficiency virus type 1 (HIV-1) infection. CD4+ T cell subsets are heterogeneous cell populations, divided by functional and phenotypic differences into naïve and memory T cells. The memory CD4+ T cells are further segregated into central, effector and transitional memory cell subsets by functional, phenotypic and homeostatic characteristics. Defining the distribution of HIV-1 infection in different T cell subsets is important, as this can play a role in determining the size and composition of the viral reservoir. Both central memory and transitional memory CD4+ T cells have been described as long-lived viral reservoirs for HIV. Recently, the newly described stem memory T cell subset has also been implicated as a long-lived HIV reservoir. Using green fluorescent protein (GFP) reporter strains of HIV-1 and multi parameter flow cytometry, we developed an assay to simultaneously quantify the susceptibility of stem memory (TSCM), central memory, effector memory, transitional memory and naïve CD4+ T cell subsets, to HIV-1 infection in vitro. We show that TSCM are susceptible to infection with laboratory adapted and clinical HIV-1 strains. Our system facilitates the quantitation of HIV-1 infection in alternative T cell subsets by CCR5- and CXCR4-using viruses across different HIV-1 subtypes, and will be useful for studies of HIV-1 pathogenesis and viral reservoirs. PMID:24517971

  20. T-cell responses to the trypanosome variant surface glycoprotein are not limited to hypervariable subregions.

    PubMed

    Dagenais, Taylor R; Demick, Karen P; Bangs, James D; Forest, Katrina T; Paulnock, Donna M; Mansfield, John M

    2009-01-01

    Variable subregions within the variant surface glycoprotein (VSG) coat displayed by African trypanosomes are predicted sites for T- and B-cell recognition. Hypervariable subregion 1 (HV-1) is localized to an internal amphipathic alpha helix in VSG monomers and may have evolved due to selective pressure by host T-cell responses to epitopes within this subregion. The prediction of T-cell receptor-reactive sites and major histocompatibility complex class II binding motifs within the HV-1 subregion, coupled with the conservation of amino acid residues in other regions of the molecule sufficient to maintain secondary and tertiary VSG structure, prompted us to test the hypothesis that Th cells may preferentially recognize HV-1 subregion peptides. Thus, we examined the fine specificity of VSG-specific T-cell lines, T-cell hybridomas, and Th cells activated during infection. Our results demonstrate that T-cell epitopes are distributed throughout the N-terminal domain of VSG but are not clustered exclusively within HV-1 or other hypervariable subregions. In contrast, T-cell-reactive sites were not detected within the relatively conserved C-terminal domain of VSG. Overall, this study is the first to dissect the fine specificity of T-cell responses to the trypanosome VSG and suggests that evolution of a conserved HV-1 region may be unrelated to selective pressures exerted by host T-cell responses. This study also demonstrates that T cells do not recognize the relatively invariant C-terminal region of the VSG molecule during infection, suggesting that it could serve as a potential subunit vaccine to provide variant cross-specific immunity for African trypanosomiasis.

  1. Lower Affinity T Cells are Critical Components and Active Participants of the Immune Response

    PubMed Central

    Martinez, Ryan J.; Evavold, Brian D.

    2015-01-01

    Kinetic and biophysical parameters of T cell receptor (TCR) and peptide:MHC (pMHC) interaction define intrinsic factors required for T cell activation and differentiation. Although receptor ligand kinetics are somewhat cumbersome to assess experimentally, TCR:pMHC affinity has been shown to predict peripheral T cell functionality and potential for forming memory. Multimeric forms of pMHC monomers have often been used to provide an indirect readout of higher affinity T cells due to their availability and ease of use while allowing simultaneous definition of other functional and phenotypic characteristics. However, multimeric pMHC reagents have introduced a bias that underestimates the lower affinity components contained in the highly diverse TCR repertoires of all polyclonal T cell responses. Advances in the identification of lower affinity cells have led to the examination of these cells and their contribution to the immune response. In this review, we discuss the identification of high- vs. low-affinity T cells as well as their attributed signaling and functional differences. Lastly, mechanisms are discussed that maintain a diverse range of low- and high-affinity T cells. PMID:26441973

  2. Epitope specific T-cell responses against influenza A in a healthy population.

    PubMed

    Savic, Miloje; Dembinski, Jennifer L; Kim, Yohan; Tunheim, Gro; Cox, Rebecca J; Oftung, Fredrik; Peters, Bjoern; Mjaaland, Siri

    2016-02-01

    Pre-existing human CD4(+) and CD8(+) T-cell-mediated immunity may be a useful correlate of protection against severe influenza disease. Identification and evaluation of common epitopes recognized by T cells with broad cross-reactivity is therefore important to guide universal influenza vaccine development, and to monitor immunological preparedness against pandemics. We have retrieved an optimal combination of MHC class I and class II restricted epitopes from the Immune Epitope Database (www.iedb.org), by defining a fitness score function depending on prevalence, sequence conservancy and HLA super-type coverage. Optimized libraries of CD4(+) and CD8(+) T-cell epitopes were selected from influenza antigens commonly present in seasonal and pandemic influenza strains from 1934 to 2009. These epitope pools were used to characterize human T-cell responses in healthy donors using interferon-γ ELISPOT assays. Upon stimulation, significant CD4(+) and CD8(+) T-cell responses were induced, primarily recognizing epitopes from the conserved viral core proteins. Furthermore, the CD4(+) and CD8(+) T cells were phenotypically characterized regarding functionality, cytotoxic potential and memory phenotype using flow cytometry. Optimized sets of T-cell peptide epitopes may be a useful tool to monitor the efficacy of clinical trials, the immune status of a population to predict immunological preparedness against pandemics, as well as being candidates for universal influenza vaccines.

  3. Highly-Immunogenic Virally-Vectored T-cell Vaccines Cannot Overcome Subversion of the T-cell Response by HCV during Chronic Infection

    PubMed Central

    Swadling, Leo; Halliday, John; Kelly, Christabel; Brown, Anthony; Capone, Stefania; Ansari, M. Azim; Bonsall, David; Richardson, Rachel; Hartnell, Felicity; Collier, Jane; Ammendola, Virginia; Del Sorbo, Mariarosaria; Von Delft, Annette; Traboni, Cinzia; Hill, Adrian V. S.; Colloca, Stefano; Nicosia, Alfredo; Cortese, Riccardo; Klenerman, Paul; Folgori, Antonella; Barnes, Eleanor

    2016-01-01

    An effective therapeutic vaccine for the treatment of chronic hepatitis C virus (HCV) infection, as an adjunct to newly developed directly-acting antivirals (DAA), or for the prevention of reinfection, would significantly reduce the global burden of disease associated with chronic HCV infection. A recombinant chimpanzee adenoviral (ChAd3) vector and a modified vaccinia Ankara (MVA), encoding the non-structural proteins of HCV (NSmut), used in a heterologous prime/boost regimen induced multi-specific, high-magnitude, durable HCV-specific CD4+ and CD8+ T-cell responses in healthy volunteers, and was more immunogenic than a heterologous Ad regimen. We now assess the immunogenicity of this vaccine regimen in HCV infected patients (including patients with a low viral load suppressed with interferon/ribavirin therapy), determine T-cell cross-reactivity to endogenous virus, and compare immunogenicity with that observed previously in both healthy volunteers and in HCV infected patients vaccinated with the heterologous Ad regimen. Vaccination of HCV infected patients with ChAd3-NSmut/MVA-NSmut was well tolerated. Vaccine-induced HCV-specific T-cell responses were detected in 8/12 patients; however, CD4+ T-cell responses were rarely detected, and the overall magnitude of HCV-specific T-cell responses was markedly reduced when compared to vaccinated healthy volunteers. Furthermore, HCV-specific cells had a distinct partially-functional phenotype (lower expression of activation markers, granzyme B, and TNFα production, weaker in vitro proliferation, and higher Tim3 expression, with comparable Tbet and Eomes expression) compared to healthy volunteers. Robust anti-vector T-cells and antibodies were induced, showing that there is no global defect in immunity. The level of viremia at the time of vaccination did not correlate with the magnitude of the vaccine-induced T-cell response. Full-length, next-generation sequencing of the circulating virus demonstrated that T-cells were

  4. Highly-Immunogenic Virally-Vectored T-cell Vaccines Cannot Overcome Subversion of the T-cell Response by HCV during Chronic Infection.

    PubMed

    Swadling, Leo; Halliday, John; Kelly, Christabel; Brown, Anthony; Capone, Stefania; Ansari, M Azim; Bonsall, David; Richardson, Rachel; Hartnell, Felicity; Collier, Jane; Ammendola, Virginia; Del Sorbo, Mariarosaria; Von Delft, Annette; Traboni, Cinzia; Hill, Adrian V S; Colloca, Stefano; Nicosia, Alfredo; Cortese, Riccardo; Klenerman, Paul; Folgori, Antonella; Barnes, Eleanor

    2016-08-02

    An effective therapeutic vaccine for the treatment of chronic hepatitis C virus (HCV) infection, as an adjunct to newly developed directly-acting antivirals (DAA), or for the prevention of reinfection, would significantly reduce the global burden of disease associated with chronic HCV infection. A recombinant chimpanzee adenoviral (ChAd3) vector and a modified vaccinia Ankara (MVA), encoding the non-structural proteins of HCV (NSmut), used in a heterologous prime/boost regimen induced multi-specific, high-magnitude, durable HCV-specific CD4+ and CD8+ T-cell responses in healthy volunteers, and was more immunogenic than a heterologous Ad regimen. We now assess the immunogenicity of this vaccine regimen in HCV infected patients (including patients with a low viral load suppressed with interferon/ribavirin therapy), determine T-cell cross-reactivity to endogenous virus, and compare immunogenicity with that observed previously in both healthy volunteers and in HCV infected patients vaccinated with the heterologous Ad regimen. Vaccination of HCV infected patients with ChAd3-NSmut/MVA-NSmut was well tolerated. Vaccine-induced HCV-specific T-cell responses were detected in 8/12 patients; however, CD4+ T-cell responses were rarely detected, and the overall magnitude of HCV-specific T-cell responses was markedly reduced when compared to vaccinated healthy volunteers. Furthermore, HCV-specific cells had a distinct partially-functional phenotype (lower expression of activation markers, granzyme B, and TNFα production, weaker in vitro proliferation, and higher Tim3 expression, with comparable Tbet and Eomes expression) compared to healthy volunteers. Robust anti-vector T-cells and antibodies were induced, showing that there is no global defect in immunity. The level of viremia at the time of vaccination did not correlate with the magnitude of the vaccine-induced T-cell response. Full-length, next-generation sequencing of the circulating virus demonstrated that T-cells were

  5. NKp46+ Innate Lymphoid Cells Dampen Vaginal CD8 T Cell Responses following Local Immunization with a Cholera Toxin-Based Vaccine

    PubMed Central

    Luci, Carmelo; Bekri, Selma; Bihl, Franck; Pini, Jonathan; Bourdely, Pierre; Nouhen, Kelly; Malgogne, Angélique; Walzer, Thierry; Braud, Véronique M.; Anjuère, Fabienne

    2015-01-01

    Innate and adaptive immune cells work in concert to generate efficient protection at mucosal surface. Vaginal mucosa is an epithelial tissue that contains innate and adaptive immune effector cells. Our previous studies demonstrated that vaginal administration of Cholera toxin -based vaccines generate antigen-specific CD8 T cells through the stimulation of local dendritic cells (DC). Innate lymphoid cells (ILC) are a group of lymphocytes localized in epithelial tissues that have important immune functions against pathogens and in tissue homeostasis. Their contribution to vaccine-induced mucosal T cell responses is an important issue for the design of protective vaccines. We report here that the vaginal mucosa contains a heterogeneous population of NKp46+ ILC that includes conventional NK cells and ILC1-like cells. We show that vaginal NKp46+ ILC dampen vaccine-induced CD8 T cell responses generated after local immunization. Indeed, in vivo depletion of NKp46+ ILC with anti-NK1.1 antibody or NKG2D blockade increases the magnitude of vaginal OVA-specific CD8 T cells. Furthermore, such treatments also increase the number of DC in the vagina. NKG2D ligands being expressed by vaginal DC but not by CD8 T cells, these results support that NKp46+ ILC limit mucosal CD8 T cell responses indirectly through the NKG2D-dependent elimination of vaginal DC. Our data reveal an unappreciated role of NKp46+ ILC in the regulation of mucosal CD8 T cell responses. PMID:26630176

  6. NKG2D+ IFN-γ+ CD8+ T Cells Are Responsible for Palladium Allergy

    PubMed Central

    Kawano, Mitsuko; Nakayama, Masafumi; Aoshima, Yusuke; Nakamura, Kyohei; Ono, Mizuho; Nishiya, Tadashi; Nakamura, Syou; Takeda, Yuri; Dobashi, Akira; Takahashi, Akiko; Endo, Misato; Ito, Akiyo; Ueda, Kyosuke; Sato, Naoki; Higuchi, Shigehito; Kondo, Takeru; Hashimoto, Suguru; Watanabe, Masamichi; Watanabe, Makoto; Takahashi, Tetsu; Sasaki, Keiichi; Nakamura, Masanori; Sasazuki, Takehiko; Narushima, Takayuki; Suzuki, Ryuji; Ogasawara, Kouetsu

    2014-01-01

    Nickel, cobalt, and chromium are well known to be causal agents of allergic contact dermatitis. Palladium (Pd) can also cause allergic disease and exposure results from wide use of this metal in dental restorations and jewelry. Metal allergy is categorized as a delayed-type hypersensitivity, and metal-responsive T cell clones have been isolated from allergic patients. However, compared to nickel, little is known about the pathology of allergic disease mediated by Pd, and pathogenic T cells are poorly understood. To identify the pathogenic T cells that are responsible for onset of Pd allergy, we enriched metal-responsive lymphocytes by sequential adoptive transfer of involved lymph node cells. Here we show that sequential adoptive transfer gradually increased the incidence and the intensity of Pd allergy, and CD8+ T cells are responsible for the disease as CD8+ T cell-depleted mice and β2-microglobulin-deficient mice did not develop Pd allergy. In addition, we found that draining lymph node cells skewed toward CD8+ T cells in response to Pd challenge in 8th adoptive transferred recipient mice. The CD8+ T cells expressed NKG2D, a costimulatory molecule involved in the production of IFN-γ. NKG2D ligand was also induced in Pd-injected tissues. Furthermore, both NKG2D ligand-transgenic mice, where NKG2D is downmodulated, and IFN-γ-deficient mice showed impaired Pd allergy. Taken together, these results indicate that IFN-γ-producing NKG2D+ CD8+ T cells are responsible for Pd allergy and suggest that NKG2D is a potential therapeutic target for treatment of metal allergy. PMID:24533050

  7. Immune response of human propagated gammadelta-T-cells to neuroblastoma recommend the Vdelta1+ subset for gammadelta-T-cell-based immunotherapy.

    PubMed

    Schilbach, Karin; Frommer, Klaus; Meier, Sybille; Handgretinger, Rupert; Eyrich, Matthias

    2008-01-01

    Human peripheral gammadelta-T-cells are able to induce cytolysis of neuroblastoma (Nb) tumor cells. Besides innate effector functions against infected cells and tumors, gammadelta-T-cells are involved in T-helper 1/T-helper 2 (TH1/TH2) differentiation of alphabeta-T-cells. However, as different gammadelta-T-cell subsets vary considerably in their functional properties, the aim of the present study was to define repertoires of cytokines, chemokines, and angiogenic factors of in vitro expanded Vdelta1+ and Vdelta2+ T cells in response to Nb. After short-term culture, both subsets released TH1 [interleukin (IL)-2, interferon (IFN)-gamma, IL-12, tumor necrosis factor (TNF)-alpha, TNF-beta)] and TH2 cytokines (IL-4, -5, -6, -10, -13, Vdelta1 also transforming growth factor (TGF)-beta, chemokines (I-309, monocyte chemotactic protein (MCP)-1-3, regulated upon activation, normal T-cell expressed and secreted), ILs (IL-1, -8, -15), cytokines (leptin) as well as angiogenic growth factors [angiogenin (ANG), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), Insulin-like growth factor (IGF)-I]. These molecules were expressed at higher levels in Vdelta2+ than Vdelta1+ T cells. Nb challenge changed protein expression. TH2 cytokine and IFN-gamma release was blocked in both gammadelta-T-cell subsets. In Vdelta2 gammadelta-T-cells, TH1 cytokines were down-regulated and tumor growth-promoting factors (ANG, VEGF, EGF, and IGF-I) were strongly up-regulated. In contrast, Vdelta1+ gammadelta-T-cells stopped the release of tumor-supportive factors and tolerogenic TGF-beta, and strongly up-regulated TNF-alpha, TNF-beta, MCP-1 and -2 and maintained their IL-2 production. In summary, our data show that after being challenged with Nb cells, propagated Vdelta1+ rather than Vdelta2+ T cells support antitumor responses by secretion of proinflammatory cytokines. Furthermore, in contrast to other cell types, Vdelta1+ T cells do not sustain a growth-promoting or tolerogenic

  8. Recovery from severe H7N9 disease is associated with diverse response mechanisms dominated by CD8+ T cells

    PubMed Central

    Wang, Zhongfang; Wan, Yanmin; Qiu, Chenli; Quiñones-Parra, Sergio; Zhu, Zhaoqin; Loh, Liyen; Tian, Di; Ren, Yanqin; Hu, Yunwen; Zhang, Xiaoyan; Thomas, Paul G.; Inouye, Michael; Doherty, Peter C.; Kedzierska, Katherine; Xu, Jianqing

    2015-01-01

    The avian origin A/H7N9 influenza virus causes high admission rates (>99%) and mortality (>30%), with ultimately favourable outcomes ranging from rapid recovery to prolonged hospitalization. Using a multicolour assay for monitoring adaptive and innate immunity, here we dissect the kinetic emergence of different effector mechanisms across the spectrum of H7N9 disease and recovery. We find that a diversity of response mechanisms contribute to resolution and survival. Patients discharged within 2–3 weeks have early prominent H7N9-specific CD8+ T-cell responses, while individuals with prolonged hospital stays have late recruitment of CD8+/CD4+ T cells and antibodies simultaneously (recovery by week 4), augmented even later by prominent NK cell responses (recovery >30 days). In contrast, those who succumbed have minimal influenza-specific immunity and little evidence of T-cell activation. Our study illustrates the importance of robust CD8+ T-cell memory for protection against severe influenza disease caused by newly emerging influenza A viruses. PMID:25967273

  9. Characterization of Human CD8 T Cell Responses in Dengue Virus-Infected Patients from India.

    PubMed

    Chandele, Anmol; Sewatanon, Jaturong; Gunisetty, Sivaram; Singla, Mohit; Onlamoon, Nattawat; Akondy, Rama S; Kissick, Haydn Thomas; Nayak, Kaustuv; Reddy, Elluri Seetharami; Kalam, Haroon; Kumar, Dhiraj; Verma, Anil; Panda, HareKrushna; Wang, Siyu; Angkasekwinai, Nasikarn; Pattanapanyasat, Kovit; Chokephaibulkit, Kulkanya; Medigeshi, Guruprasad R; Lodha, Rakesh; Kabra, Sushil; Ahmed, Rafi; Murali-Krishna, Kaja

    2016-12-15

    Epidemiological studies suggest that India has the largest number of dengue virus infection cases worldwide. However, there is minimal information about the immunological responses in these patients. CD8 T cells are important in dengue, because they have been implicated in both protection and immunopathology. Here, we provide a detailed analysis of HLA-DR(+) CD38(+) and HLA-DR(-) CD38(+) effector CD8 T cell subsets in dengue patients from India and Thailand. Both CD8 T cell subsets expanded and expressed markers indicative of antigen-driven proliferation, tissue homing, and cytotoxic effector functions, with the HLA-DR(+) CD38(+) subset being the most striking in these effector qualities. The breadth of the dengue-specific CD8 T cell response was diverse, with NS3-specific cells being the most dominant. Interestingly, only a small fraction of these activated effector CD8 T cells produced gamma interferon (IFN-γ) when stimulated with dengue virus peptide pools. Transcriptomics revealed downregulation of key molecules involved in T cell receptor (TCR) signaling. Consistent with this, the majority of these CD8 T cells remained IFN-γ unresponsive even after TCR-dependent polyclonal stimulation (anti-CD3 plus anti-CD28) but produced IFN-γ by TCR-independent polyclonal stimulation (phorbol 12-myristate 13-acetate [PMA] plus ionomycin). Thus, the vast majority of these proliferating, highly differentiated effector CD8 T cells probably acquire TCR refractoriness at the time the patient is experiencing febrile illness that leads to IFN-γ unresponsiveness. Our studies open novel avenues for understanding the mechanisms that fine-tune the balance between CD8 T cell-mediated protective versus pathological effects in dengue.

  10. Dynamics of the Cytotoxic T Cell Response to a Model of Acute Viral Infection

    PubMed Central

    DeWitt, William S.; Emerson, Ryan O.; Lindau, Paul; Vignali, Marissa; Snyder, Thomas M.; Desmarais, Cindy; Sanders, Catherine; Utsugi, Heidi; Warren, Edus H.; McElrath, Juliana; Makar, Karen W.; Wald, Anna

    2015-01-01

    ABSTRACT A detailed characterization of the dynamics and breadth of the immune response to an acute viral infection, as well as the determinants of recruitment to immunological memory, can greatly contribute to our basic understanding of the mechanics of the human immune system and can ultimately guide the design of effective vaccines. In addition to neutralizing antibodies, T cells have been shown to be critical for the effective resolution of acute viral infections. We report the first in-depth analysis of the dynamics of the CD8+ T cell repertoire at the level of individual T cell clonal lineages upon vaccination of human volunteers with a single dose of YF-17D. This live attenuated yellow fever virus vaccine yields sterile, long-term immunity and has been previously used as a model to understand the immune response to a controlled acute viral infection. We identified and enumerated unique CD8+ T cell clones specifically induced by this vaccine through a combined experimental and statistical approach that included high-throughput sequencing of the CDR3 variable region of the T cell receptor β-chain and an algorithm that detected significantly expanded T cell clones. This allowed us to establish that (i) on average, ∼2,000 CD8+ T cell clones were induced by YF-17D, (ii) 5 to 6% of the responding clones were recruited to long-term memory 3 months postvaccination, (iii) the most highly expanded effector clones were preferentially recruited to the memory compartment, and (iv) a fraction of the YF-17D-induced clones could be identified from peripheral blood lymphocytes solely by measuring clonal expansion. IMPORTANCE The exhaustive investigation of pathogen-induced effector T cells is essential to accurately quantify the dynamics of the human immune response. The yellow fever vaccine (YFV) has been broadly used as a model to understand how a controlled, self-resolving acute viral infection induces an effective and long-term protective immune response. Here, we

  11. Dendritic cell-derived IL-15 controls the induction of CD8 T cell immune responses.

    PubMed

    Rückert, René; Brandt, Katja; Bulanova, Elena; Mirghomizadeh, Farhad; Paus, Ralf; Bulfone-Paus, Silvia

    2003-12-01

    The development and the differentiation of CD8(+) T cells are dependent on IL-15. Here, we have studied the source and mechanism of how IL-15 modulates CD8(+) T cell-mediated Th1 immune responses by employing two delayed-type hypersensitivity (DTH) models. IL-15-deficient (IL-15(-/-)) mice or mice treated with soluble IL-15Ralpha as an IL-15 antagonist showed significantly reduced CD8(+) T cell-dependent DTH responses, while activation of CD4(+) T cell and B cell functions remained unaffected. Injection of antigen-labeled dendritic cells (DC) from IL-15(+/+), IL-15(-/-) or IL-15Ralpha(-/-) mice revealed that DC-derived IL-15 is an absolute requirement for the initiation of DTH response. The re-establishment of the interaction of IL-15 with the IL-15Ralpha by incubating IL-15(-/-) DC with IL-15 completely restored the capacity to prime T cells for DTH induction in vivo. Moreover, IL-15 also enhanced secretion of pro-inflammatory cytokines by DC and triggered in vitro CD8(+) T cell proliferation and IL-2 release. Taken together, the data suggest that an autocrine IL-15/IL-15Ralpha signaling loop in DC is essential for inducing CD8(+)-dependent Th1 immune responses in mice. Therefore, targeted manipulation of this loop promises to be an effective, novel strategy for therapeutic modulation of clinically relevant DTH reactions.

  12. T-cell responses associated with neonatal alloimmune thrombocytopenia: isolation of HPA-1a-specific, HLA-DRB3*0101-restricted CD4+ T cells.

    PubMed

    Ahlen, Maria Therese; Husebekk, Anne; Killie, Mette Kjaer; Skogen, Bjørn; Stuge, Tor B

    2009-04-16

    T-cell responses have been implicated in the development of HPA-1a-induced neonatal alloimmune thrombocytopenia (NAIT). However, HPA-1a-specific T cells have neither been isolated nor characterized. Here, we aimed to determine whether HPA-1a-specific T cells could be isolated from HPA-1a-immunized women. In the present study, peripheral blood mononuclear cells (PBMCs) from an HPA-1a-alloimmunized woman were cultured for weeks in the presence of HPA-1a peptide, labeled with CFSE, and assayed for antigen-specific proliferation. Individual proliferating cells were isolated by fluorescence-activated cell sorting and expanded in culture. Antigen specificity and HLA restriction were determined by cytokine secretion (enzyme-linked immunospot [ELISPOT]) and proliferation assays. Several CD3(+)CD4(+) T-cell clones were isolated that proliferated and secreted cytokines in response to HPA-1a peptide. Two of these clones have been established in long-term culture in our laboratory. Both of these recognize synthetic as well as naturally processed HPA-1a antigen, and the recognition is restricted by the MHC molecule HLA-DRB3*0101 that is strongly associated with NAIT. These HPA-1a-specific T-cell clones represent unambiguous evidence for the association of T-cell responses with NAIT, and they will serve as unique tools to elucidate the cellular immune response that may result in NAIT.

  13. AMPK-dependent and independent effects of AICAR and compound C on T-cell responses.

    PubMed

    Rao, Enyu; Zhang, Yuwen; Li, Qiang; Hao, Jiaqing; Egilmez, Nejat K; Suttles, Jill; Li, Bing

    2016-06-07

    As a master metabolic sensor, AMP-activated protein kinase (AMPK) is involved in different fundamental cellular processes. Regulation of AMPK activity either by agonists (e.g., AICAR) or by antagonists (e.g., Compound C) has been widely employed to study the physiological functions of AMPK. However, mounting evidence indicates AMPK-independent effects for these chemicals and how they regulate immune cell functions remains largely unknown. Herein, using T cells from AMPK conditional knockout mice and their wild type littermates, we demonstrate that AICAR and Compound C can, indeed, activate or inhibit AMPK activity in T cells, respectively. Specifically, AICAR inhibits, but Compound C promotes, Ca2+-induced T cell death in an AMPK-dependent manner. In contrast, our data also demonstrate that AICAR and Compound C inhibit T cell activation and cytokine production in an AMPK-independent manner. Moreover, we find that the AMPK-independent activity of AICAR and Compound Cis mediated via the mTOR signaling pathway in activated T cells. Our results not only reveal the critical role of AMPK in regulating T cell survival and function, but also demonstrate AMPK-dependent and independent rolesof AICAR/Compound C in regulating T cell responses, thus suggesting a context-dependent effect of these "AMPK regulators".

  14. Functional Signatures of Human CD4 and CD8 T Cell Responses to Mycobacterium tuberculosis.

    PubMed

    Prezzemolo, Teresa; Guggino, Giuliana; La Manna, Marco Pio; Di Liberto, Diana; Dieli, Francesco; Caccamo, Nadia

    2014-01-01

    With 1.4 million deaths and 8.7 million new cases in 2011, tuberculosis (TB) remains a global health care problem and together with HIV and Malaria represents one of the three infectious diseases world-wide. Control of the global TB epidemic has been impaired by the lack of an effective vaccine, by the emergence of drug-resistant forms of Mycobacterium tuberculosis (Mtb) and by the lack of sensitive and rapid diagnostics. It is estimated, by epidemiological reports, that one third of the world's population is latently infected with Mtb, but the majority of infected individuals develop long-lived protective immunity, which controls and contains Mtb in a T cell-dependent manner. Development of TB disease results from interactions among the environment, the host, and the pathogen, and known risk factors include HIV co-infection, immunodeficiency, diabetes mellitus, overcrowding, malnutrition, and general poverty; therefore, an effective T cell response determines whether the infection resolves or develops into clinically evident disease. Consequently, there is great interest in determining which T cells subsets mediate anti-mycobacterial immunity, delineating their effector functions. On the other hand, many aspects remain unsolved in understanding why some individuals are protected from Mtb infection while others go on to develop disease. Several studies have demonstrated that CD4(+) T cells are involved in protection against Mtb, as supported by the evidence that CD4(+) T cell depletion is responsible for Mtb reactivation in HIV-infected individuals. There are many subsets of CD4(+) T cells, such as T-helper 1 (Th1), Th2, Th17, and regulatory T cells (Tregs), and all these subsets co-operate or interfere with each other to control infection; the dominant subset may differ between active and latent Mtb infection cases. Mtb-specific-CD4(+) Th1 cell response is considered to have a protective role for the ability to produce cytokines such as IFN-γ or TNF-α that

  15. Characterization of γδ T Cells from Zebrafish Provides Insights into Their Important Role in Adaptive Humoral Immunity

    PubMed Central

    Wan, Feng; Hu, Chong-bin; Ma, Jun-xia; Gao, Ke; Xiang, Li-xin; Shao, Jian-zhong

    2017-01-01

    γδ T cells represent an evolutionarily primitive T cell subset characterized by distinct T cell receptors (TCRs) and innate and adaptive immune functions. However, the presence of this T cell subset in ancient vertebrates remains unclear. In this study, γδ T cells from a zebrafish (Danio rerio) model were subjected to molecular and cellular characterizations. The constant regions of zebrafish TCR-γ (DrTRGC) and δ (DrTRDC) were initially identified. Zebrafish γδ T cells accounted for 7.7–20.5% of the total lymphocytes in spleen, head kidney, peripheral blood, skin, gill, and intestine tissues. They possess typical morphological features of lymphocytes with a surface phenotype of γ+δ+CD4−CD8+. Zebrafish γδ T cells functionally showed a potent phagocytic ability to both soluble and particulate antigens. They can also act as an antigen-presenting cell to initiate antigen (KLH)-specific CD4+ TKLH cell activation and to induce B cell proliferation and IgM production. Particularly, zebrafish γδ T cells also play a critical role in antigen-specific IgZ production in intestinal mucus. These findings demonstrated that γδ T cells had been originated as early as teleost fish, which providing valuable insights into the evolutionary history of T cell subset. It is anticipated that this study would be used as a guide to develop a zebrafish model for the cross-species investigation of γδ T cell biology. PMID:28119690

  16. Braking bad: novel mechanisms of CTLA-4 inhibition of T cell responses.

    PubMed

    Krummey, S M; Ford, M L

    2014-12-01

    The coinhibitory receptor cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a master regulator of T cell responses and its function is critical in models of transplant tolerance. The CD28/CTLA-4 pathway is also an important therapeutic target, as the costimulation blocker belatacept was recently approved for use following renal transplantation. While the traditional model of CTLA-4 coinhibition focuses on its ability to directly counteract CD28 costimulation, recently this paradigm has significantly broadened. Recent work has uncovered the ability of CTLA-4 to act as a cell-extrinsic coinhibitory molecule on CD4(+) T cell effectors. While it has been appreciated that CTLA-4 is required for FoxP3(+) regulatory T cell (Treg) suppression, current studies have elucidated important differences in the function of CTLA-4 on Tregs compared to effectors. CTLA-4 expression patterns also differ by T cell subset, with Th17 cells expressing significantly higher levels of CTLA-4. Thus, in contrast to the traditional model of CTLA-4 as a negative receptor to counter CD28 costimulation, recent work has begun to define CTLA-4 as a global regulator of T cell responses with subset-specific functions. Future studies must continue to uncover the molecular mechanisms that govern CTLA-4 function. These novel findings have implications for novel strategies to maximize the regulatory potential of CTLA-4 during allogeneic T cell responses.

  17. Cannabidiol (CBD) induces functional Tregs in response to low-level T cell activation.

    PubMed

    Dhital, Saphala; Stokes, John V; Park, Nogi; Seo, Keun Seok; Kaplan, Barbara L F

    2017-02-01

    Many effects of the non-psychoactive cannabinoid, cannabidiol (CBD), have been described in immune responses induced by strong immunological stimuli. It has also been shown that CBD enhances IL-2 production in response to low-level T cell stimulation. Since IL-2, in combination with TGF-β1, are critical for Treg induction, we hypothesized that CBD would induce CD4(+)CD25(+)FOXP3(+) Tregs in response to low-level stimulation. Low-level T cell stimulation conditions were established based on minimal CD25 expression in CD4(+) cells using suboptimal PMA/Io (4nM/0.05μM, S/o), ultrasuboptimal PMA/Io (1nM/0.0125μM, Us/o) or soluble anti-CD3/28 (400-800ng each, s3/28). CBD increased CD25(+)FOXP3(+) cells from CD4(+), CD4(+)CD25(+), and CD4(+)CD25(-) T cells, as well as in CD4(+) T cells derived from FOXP3-GFP mice. Most importantly, the Us/o+CBD-induced CD4(+)CD25(+) Tregs robustly suppressed responder T cell proliferation, demonstrating that the mechanism by which CBD is immunosuppressive under low-level T cell stimulation involves induction of functional Tregs.

  18. Salmonella impairs CD8 T cell response through PD-1: PD-L axis.

    PubMed

    López-Medina, Marcela; Carrillo-Martín, Ismael; Leyva-Rangel, Jessica; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2015-12-01

    We have shown that Salmonella remains for a long period of time within B cells, plasma cells, and bone marrow B cell precursors, which might allow persistence and dissemination of infection. Nonetheless, how infected cells evade CD8 T cell response has not been characterized. Evidence indicates that some pathogens exploit the PD-1: PD-L (PD-L1 and PD-L2) interaction to inhibit CD8 T cells response to contribute the chronicity of the infection. To determine whether the PD-1: PD-L axis plays a role during Salmonella infection; we evaluated PD-1 expression in antigen-specific CD8 T cells and PD-1 ligands in Salmonella-infected cells. Our results show that infected B cells and macrophages express continuously co-stimulatory (CD40, CD80, and CD86) and inhibitory molecules (PD-L1 and PD-L2) in early and late stages of chronic Salmonella infection, while antigen-specific CD8 T cells express in a sustained manner PD-1 in the late stages of infection. Blocking this axis restores the ability of the CD8 T cells to proliferate and eliminate primary infected APCs. Therefore, a continuous PD-1: PDL interaction might be a mechanism employed by Salmonella to negatively regulate Salmonella-specific CD8 T cell cytotoxic response in order to remain within the host for a long period of time.

  19. The use of fluorescent target arrays for assessment of T cell responses in vivo.

    PubMed

    Quah, Benjamin J C; Wijesundara, Danushka K; Ranasinghe, Charani; Parish, Christopher R

    2014-06-19

    The ability to monitor T cell responses in vivo is important for the development of our understanding of the immune response and the design of immunotherapies. Here we describe the use of fluorescent target array (FTA) technology, which utilizes vital dyes such as carboxyfluorescein succinimidyl ester (CFSE), violet laser excitable dyes (CellTrace Violet: CTV) and red laser excitable dyes (Cell Proliferation Dye eFluor 670: CPD) to combinatorially label mouse lymphocytes into > 250 discernable fluorescent cell clusters. Cell clusters within these FTAs can be pulsed with major histocompatibility (MHC) class-I and MHC class-II binding peptides and thereby act as target cells for CD8(+) and CD4(+) T cells, respectively. These FTA cells remain viable and fully functional, and can therefore be administered into mice to allow assessment of CD8(+) T cell-mediated killing of FTA target cells and CD4(+) T cell-meditated help of FTA B cell target cells in real time in vivo by flow cytometry. Since > 250 target cells can be assessed at once, the technique allows the monitoring of T cell responses against several antigen epitopes at several concentrations and in multiple replicates. As such, the technique can measure T cell responses at both a quantitative (e.g. the cumulative magnitude of the response) and a qualitative (e.g. functional avidity and epitope-cross reactivity of the response) level. Herein, we describe how these FTAs are constructed and give an example of how they can be applied to assess T cell responses induced by a recombinant pox virus vaccine.

  20. Long-Lived CD4+IFN-γ+ T Cells rather than Short-Lived CD4+IFN-γ+IL-10+ T Cells Initiate Rapid IL-10 Production To Suppress Anamnestic T Cell Responses during Secondary Malaria Infection

    PubMed Central

    Villegas-Mendez, Ana; Inkson, Colette A.; Shaw, Tovah N.; Strangward, Patrick

    2016-01-01

    CD4+ T cells that produce IFN-γ are the source of host-protective IL-10 during primary infection with a number of different pathogens, including Plasmodium spp. The fate of these CD4+IFN-γ+IL-10+ T cells following clearance of primary infection and their subsequent influence on the course of repeated infections is, however, presently unknown. In this study, utilizing IFN-γ–yellow fluorescent protein (YFP) and IL-10–GFP dual reporter mice, we show that primary malaria infection–induced CD4+YFP+GFP+ T cells have limited memory potential, do not stably express IL-10, and are disproportionately lost from the Ag-experienced CD4+ T cell memory population during the maintenance phase postinfection. CD4+YFP+GFP+ T cells generally exhibited a short-lived effector rather than effector memory T cell phenotype postinfection and expressed high levels of PD-1, Lag-3, and TIGIT, indicative of cellular exhaustion. Consistently, the surviving CD4+YFP+GFP+ T cell–derived cells were unresponsive and failed to proliferate during the early phase of secondary infection. In contrast, CD4+YFP+GFP− T cell–derived cells expanded rapidly and upregulated IL-10 expression during secondary infection. Correspondingly, CD4+ T cells were the major producers within an accelerated and amplified IL-10 response during the early stage of secondary malaria infection. Notably, IL-10 exerted quantitatively stronger regulatory effects on innate and CD4+ T cell responses during primary and secondary infections, respectively. The results in this study significantly improve our understanding of the durability of IL-10–producing CD4+ T cells postinfection and provide information on how IL-10 may contribute to optimized parasite control and prevention of immune-mediated pathology during repeated malaria infections. PMID:27630165

  1. Accumulation of Splice Variants and Transcripts in Response to PI3K Inhibition in T Cells

    PubMed Central

    Riedel, Alice; Mofolo, Boitumelo; Avota, Elita; Schneider-Schaulies, Sibylle; Meintjes, Ayton; Mulder, Nicola; Kneitz, Susanne

    2013-01-01

    Background Measles virus (MV) causes T cell suppression by interference with phosphatidylinositol-3-kinase (PI3K) activation. We previously found that this interference affected the activity of splice regulatory proteins and a T cell inhibitory protein isoform was produced from an alternatively spliced pre-mRNA. Hypothesis Differentially regulated and alternatively splice variant transcripts accumulating in response to PI3K abrogation in T cells potentially encode proteins involved in T cell silencing. Methods To test this hypothesis at the cellular level, we performed a Human Exon 1.0 ST Array on RNAs isolated from T cells stimulated only or stimulated after PI3K inhibition. We developed a simple algorithm based on a splicing index to detect genes that undergo alternative splicing (AS) or are differentially regulated (RG) upon T cell suppression. Results Applying our algorithm to the data, 9% of the genes were assigned as AS, while only 3% were attributed to RG. Though there are overlaps, AS and RG genes differed with regard to functional regulation, and were found to be enriched in different functional groups. AS genes targeted extracellular matrix (ECM)-receptor interaction and focal adhesion pathways, while RG genes were mainly enriched in cytokine-receptor interaction and Jak-STAT. When combined, AS/RG dependent alterations targeted pathways essential for T cell receptor signaling, cytoskeletal dynamics and cell cycle entry. Conclusions PI3K abrogation interferes with key T cell activation processes through both differential expression and alternative splicing, which together actively contribute to T cell suppression. PMID:23383294

  2. Reduced frequency of memory T cells and increased Th17 responses in patients with active tuberculosis.

    PubMed

    Marín, Nancy D; París, Sara C; Rojas, Mauricio; García, Luis F

    2012-10-01

    Phenotypic and functional alterations in Mycobacterium tuberculosis T cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, the ex vivo phenotype of CD4(+) and CD8(+) T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4(+) CD45RO(+) CD27(+) T cells and an increased frequency of CD4(+) CD45RO(-) CD27(+) T cells. ATB also had a higher frequency of circulating IL-17-producing CD4(+) T cells than did LTBi after PPD stimulation, whereas LTBi had more IFN-γ-producing CD4(+) T cells than did non-TBi. The phenotype of IFN-γ-producing cells at 24 h differs from the phenotype of IL-17-producing cells with no differences between LTBi and ATB. At 144 h, IFN-γ- and IL-17-producing cells were mainly CD45RO(+) CD27(+) T cells and they were more frequent in ATB. These results suggest that M. tuberculosis infection induces alterations in T cells which interfere with an adequate specific immune response.

  3. Reduced Frequency of Memory T Cells and Increased Th17 Responses in Patients with Active Tuberculosis

    PubMed Central

    Marín, Nancy D.; París, Sara C.; Rojas, Mauricio

    2012-01-01

    Phenotypic and functional alterations in Mycobacterium tuberculosis T cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, the ex vivo phenotype of CD4+ and CD8+ T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4+ CD45RO+ CD27+ T cells and an increased frequency of CD4+ CD45RO− CD27+ T cells. ATB also had a higher frequency of circulating IL-17-producing CD4+ T cells than did LTBi after PPD stimulation, whereas LTBi had more IFN-γ-producing CD4+ T cells than did non-TBi. The phenotype of IFN-γ-producing cells at 24 h differs from the phenotype of IL-17-producing cells with no differences between LTBi and ATB. At 144 h, IFN-γ- and IL-17-producing cells were mainly CD45RO+ CD27+ T cells and they were more frequent in ATB. These results suggest that M. tuberculosis infection induces alterations in T cells which interfere with an adequate specific immune response. PMID:22914361

  4. Evolution of MHC-based technologies used for detection of antigen-responsive T cells.

    PubMed

    Bentzen, Amalie Kai; Hadrup, Sine Reker

    2017-03-17

    T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role in the development of autoimmune diseases. Novel insights into this mechanism are crucial to understanding disease development and establishing new treatment strategies. MHC multimers have been used for detection of antigen-responsive T cells since the first report by Altman et al. showed that tetramerization of pMHC class I molecules provided sufficient stability to T cell receptor (TCR)-pMHC interactions, allowing detection of MHC multimer-binding T cells using flow cytometry. Since this breakthrough the scientific community has aimed for expanding the capacity of MHC multimer-based detection technologies to facilitate large-scale epitope discovery and immune monitoring in limited biological material. Screening of T cell specificity using large libraries of pMHC molecules is suitable for analyses of T cell recognition potentially at genome-wide levels rather than analyses restricted to a selection of model antigens. Such strategies provide novel insights into the immune specificities involved in disease development and response to immunotherapy, and extend fundamental knowledge related to T cell recognition patterns and cross-recognition by TCRs. MHC multimer-based technologies have now evolved from detection of 1-2 different T cell specificities per cell sample, to include more than 1000 evaluable pMHC molecules using novel technologies. Here, we provide an overview of MHC multimer-based detection technologies developed over two decades, focusing primarily on MHC class I interactions.

  5. Echinacea purpurea (L.) Moench modulates human T-cell cytokine response.

    PubMed

    Fonseca, Fabiana N; Papanicolaou, Genovefa; Lin, Hong; Lau, Clara B S; Kennelly, Edward J; Cassileth, Barrie R; Cunningham-Rundles, Susanna

    2014-03-01

    The study objective was to evaluate the composition of a neutral and weakly acidic water-soluble extract from Echinacea purpurea (L.) Moench (EchNWA) previously shown to modify murine influenza infection, and to assess immunomodulatory effects on human T-cells. EchNWA extract from fresh aerial parts was extracted with water, ethanolic precipitation, and size-exclusion chromatography. The chemical profile of EchNWA was characterized by chromatography (size-exclusion, HPLC, GC-MS), and small molecule fingerprint analysis performed by HPLC-PDA. Jurkat T-cells at high and low cell density were pretreated or not with doses of EchNWA, followed by activation with phorbol 12-myristate 13-acetate plus ionomycin (PMA+I). Interleukin-2 (IL-2) and interferon gamma (IFNg) cytokine secretions were measured by multi-cytokine luminex technology. Results showed that EchNWA contains 80% polysaccharides, predominantly a 10kDa entity; phenolic compounds, cynarin, cichoric and caftaric acids, but no detectable alkylamides. Cytokine production required stimulation and was lower after PMA+I activation in high-density compared to low-density conditions. EchNWA mediated a strong dose-dependent enhancement of high-density T-cell production of IL-2 and IFNg response to PMA+I. EchNWA alone did not stimulate T-cells. EchNWA enhanced mean fluorescence intensity of IL-2 in Jurkat T-cells activated by PMA+1 or ionomycin alone. Conversely EchNWA mediated modest but significant suppression of IFNg response and reduced the percentage of CD25+ T-cells under low-density conditions. Conclusions are that EchNWA polysaccharides, but not phenolic compounds have dose-related adjuvant effects on human T-cell cytokine responses characterized by enhancing and suppressive effects that are regulated by T-cell density.

  6. IDO2 Modulates T Cell-Dependent Autoimmune Responses through a B Cell-Intrinsic Mechanism.

    PubMed

    Merlo, Lauren M F; DuHadaway, James B; Grabler, Samantha; Prendergast, George C; Muller, Alexander J; Mandik-Nayak, Laura

    2016-06-01

    Mechanistic insight into how adaptive immune responses are modified along the self-nonself continuum may offer more effective opportunities to treat autoimmune disease, cancer, and other sterile inflammatory disorders. Recent genetic studies in the KRN mouse model of rheumatoid arthritis demonstrate that the immunomodulatory molecule IDO2 modifies responses to self-antigens; however, the mechanisms involved are obscure. In this study, we show that IDO2 exerts a critical function in B cells to support the generation of autoimmunity. In experiments with IDO2-deficient mice, adoptive transplant experiments demonstrated that IDO2 expression in B cells was both necessary and sufficient to support robust arthritis development. IDO2 function in B cells was contingent on a cognate, Ag-specific interaction to exert its immunomodulatory effects on arthritis development. We confirmed a similar requirement in an established model of contact hypersensitivity, in which IDO2-expressing B cells are required for a robust inflammatory response. Mechanistic investigations showed that IDO2-deficient B cells lacked the ability to upregulate the costimulatory marker CD40, suggesting IDO2 acts at the T-B cell interface to modulate the potency of T cell help needed to promote autoantibody production. Overall, our findings revealed that IDO2 expression by B cells modulates autoimmune responses by supporting the cross talk between autoreactive T and B cells.

  7. Antibody-Independent Function of Human B Cells Contributes to Antifungal T Cell Responses.

    PubMed

    Li, Rui; Rezk, Ayman; Li, Hulun; Gommerman, Jennifer L; Prat, Alexandre; Bar-Or, Amit

    2017-04-15

    Fungal infections (e.g., Candida albicans) can manifest as serious medical illnesses, especially in the elderly and immune-compromised hosts. T cells are important for Candida control. Whether and how B cells are involved in antifungal immunity has been less clear. Although patients with agammaglobulinemia exhibit normal antifungal immunity, increased fungal infections are reported following B cell-depleting therapy, together pointing to Ab-independent roles of B cells in controlling such infections. To test how human B cells may contribute to fungal-associated human T cell responses, we developed a novel Ag-specific human T cell/B cell in vitro coculture system and found that human B cells could induce C. albicans-associated, MHC class II-restricted responses of naive T cells. Activated B cells significantly enhanced C. albicans-mediated Th1 and Th17 T cell responses, which were both strongly induced by CD80/CD86 costimulation. IL-6(+)GM-CSF(+) B cells were the major responding B cell subpopulation to C. albicans and provided efficient costimulatory signals to the T cells. In vivo B cell depletion in humans resulted in reduced C. albicans-associated T responses. Of note, the decreased Th17, but not Th1, responses could be reversed by soluble factors from B cells prior to depletion, in an IL-6-dependent manner. Taken together, our results implicate an Ab-independent cytokine-defined B cell role in human antifungal T cell responses. These findings may be particularly relevant given the prospects of chronic B cell depletion therapy use in lymphoma and autoimmune disease, as patients age and are exposed to serial combination therapies.

  8. Regional variation in the correlation of antibody and T-cell responses to Trypanosoma cruzi.

    PubMed

    Martin, Diana L; Marks, Morgan; Galdos-Cardenas, Gerson; Gilman, Robert H; Goodhew, Brook; Ferrufino, Lisbeth; Halperin, Anthony; Sanchez, Gerardo; Verastegui, Manuela; Escalante, Patricia; Naquira, Cesar; Levy, Michael Z; Bern, Caryn

    2014-06-01

    Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major cause of morbidity and mortality in Central and South America. Geographic variations in the sensitivity of serologic diagnostic assays to T. cruzi may reflect differences in T. cruzi exposure. We measured parasite-specific T-cell responses among seropositive individuals in two populations from South America with widely varying antibody titers against T. cruzi. Antibody titers among seropositive individuals were significantly lower in Arequipa, Peru compared with Santa Cruz, Bolivia. Similarly, the proportion of seropositive individuals with positive T-cell responses was lower in Peru than Bolivia, resulting in overall lower frequencies of interferon-γ (IFNγ)-secreting cells from Peruvian samples. However, the magnitude of the IFNγ response was similar among the IFNγ responders in both locations. These data indicate that immunological discrepancies based on geographic region are reflected in T-cell responses as well as antibody responses.

  9. Regional Variation in the Correlation of Antibody and T-Cell Responses to Trypanosoma cruzi

    PubMed Central

    Martin, Diana L.; Marks, Morgan; Galdos-Cardenas, Gerson; Gilman, Robert H.; Goodhew, Brook; Ferrufino, Lisbeth; Halperin, Anthony; Sanchez, Gerardo; Verastegui, Manuela; Escalante, Patricia; Naquira, Cesar; Levy, Michael Z.; Bern, Caryn

    2014-01-01

    Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major cause of morbidity and mortality in Central and South America. Geographic variations in the sensitivity of serologic diagnostic assays to T. cruzi may reflect differences in T. cruzi exposure. We measured parasite-specific T-cell responses among seropositive individuals in two populations from South America with widely varying antibody titers against T. cruzi. Antibody titers among seropositive individuals were significantly lower in Arequipa, Peru compared with Santa Cruz, Bolivia. Similarly, the proportion of seropositive individuals with positive T-cell responses was lower in Peru than Bolivia, resulting in overall lower frequencies of interferon-γ (IFNγ)-secreting cells from Peruvian samples. However, the magnitude of the IFNγ response was similar among the IFNγ responders in both locations. These data indicate that immunological discrepancies based on geographic region are reflected in T-cell responses as well as antibody responses. PMID:24710614

  10. Tissue damage-associated "danger signals" influence T-cell responses that promote the progression of preneoplasia to cancer.

    PubMed

    He, Ying; Zha, Jikun; Wang, Yamin; Liu, Wenhua; Yang, Xuanming; Yu, Ping

    2013-01-15

    T-cell responses may be shaped by sterile "danger signals" that are constituted by damage-associated molecular patterns (DAMP). However, whether and what type of adaptive immune responses are triggered in vivo by DAMPs induced by tumor progression are not well characterized. In this study, we report that the production of HMGB1, an established DAMP released by dying cells, was critical for tumor progression in an established mouse model of prostate cancer. HMGB1 was required for the activation and intratumoral accumulation of T cells that expressed cytokine lymphotoxinα(1)β(2) (LT) on their surface. Intriguingly, these tumor-activated T cells recruited macrophages to the lesion and were essential to promote the preneoplasia to invasive carcinoma in an LTβ receptor (LTβR)-dependent manner. Taken together, our findings suggest that the release of HMGB1 as an endogenous danger signal is important for priming an adaptive immune response that promotes malignant progression, with implications for cancer prevention and therapy.

  11. Rapid CD4+ T-cell responses to bacterial flagellin require dendritic cell expression of Syk and CARD9

    PubMed Central

    Atif, Shaikh M; Lee, Seung-Joo; Li, Lin-Xi; Uematsu, Satoshi; Akira, Shizuo; Gorjestani, Sara; Lin, Xin; Schweighoffer, Edina; Tybulewicz, Victor L J; McSorley, Stephen J

    2015-01-01

    Toll-like receptors (TLRs) can recognize microbial patterns and utilize adaptor molecules, such as-MyD88 or (TRIF TIR-domain-containing adapter-inducing interferon-β), to initiate downstream signaling that ultimately affects the initiation of adaptive immunity. In addition to this inflammatory role, TLR5 expression on dendritic cells can favor antigen presentation of flagellin peptides and thus increase the sensitivity of flagellin-specific T-cell responses in vitro and in vivo. Here, we examined the role of alternative signaling pathways that might regulate flagellin antigen presentation in addition to MyD88. These studies suggest a requirement for spleen tyrosine kinase, a noncanonical TLR-signaling adaptor molecule, and its downstream molecule CARD9 in regulating the sensitivity of flagellin-specific CD4+ T-cell responses in vitro and in vivo. Thus, a previously unappreciated signaling pathway plays an important role in regulating the dominance of flagellin-specific T-cell responses. PMID:25430631

  12. Differences in T-cell responses between Mycobacterium tuberculosis and Mycobacterium africanum-infected patients.

    PubMed

    Tientcheu, Leopold D; Sutherland, Jayne S; de Jong, Bouke C; Kampmann, Beate; Jafali, James; Adetifa, Ifedayo M; Antonio, Martin; Dockrell, Hazel M; Ota, Martin O

    2014-05-01

    In The Gambia, Mycobacterium tuberculosis (Mtb) and Mycobacterium africanum (Maf) are major causes of tuberculosis (TB). Maf is more likely to cause TB in immune suppressed individuals, implying differences in virulence. Despite this, few studies have assessed the underlying immunity to the two pathogens in human. In this study, we analyzed T-cell responses from 19 Maf- and 29 Mtb-infected HIV-negative patients before and after TB chemotherapy following overnight stimulation of whole blood with TB-specific antigens. Before treatment, percentages of early secreted antigenic target-6(ESAT-6)/culture filtrate protein-10(CFP-10) and purified protein derivative-specific single-TNF-α-producing CD4(+) and CD8(+) T cells were significantly higher while single-IL-2-producing T cells were significantly lower in Maf- compared with Mtb-infected patients. Purified protein derivative-specific polyfunctional CD4(+) T cells frequencies were significantly higher before than after treatment, but there was no difference between the groups at both time points. Furthermore, the proportion of CD3(+) CD11b(+) T cells was similar in both groups pretreatment, but was significantly lower with higher TNF-α, IL-2, and IFN-γ production in Mtb- compared with that of Maf-infected patients posttreatment. Our data provide evidence of differences in T-cell responses to two mycobacterial strains with differing virulence, providing some insight into TB pathogenesis with different Mtb strains that could be prospectively explored as biomarkers for TB protection or susceptibility.

  13. Multiple T-cell responses are associated with better control of acute HIV-1 infection

    PubMed Central

    Sun, Jianping; Zhao, Yan; Peng, Yanchun; Han, Zhen; Liu, Guihai; Qin, Ling; Liu, Sai; Sun, Huanhuan; Wu, Hao; Dong, Tao; Zhang, Yonghong

    2016-01-01

    Abstract Cytotoxic T lymphocyte (CTL) responses play pivotal roles in controlling the replication of human immunodeficiency virus type 1 (HIV-1), but the correlation between CTL responses and the progression of HIV-1 infection are controversial on account of HIV immune escape mutations driven by CTL pressure were reported. The acute HIV-1-infected patients from Beijing were incorporated into our study to investigate the effects of CTL response on the progression of HIV-1 infection. A longitudinal study was performed on acute HIV-1-infected patients to clarify the kinetic of T-cell responses, the dynamic of escape mutations, as well as the correlation between effective T-cell response and the progression of HIV infection. Seven human leukocyte antigen-B51+ (HLA-B51+) individuals were screened from 105 acute HIV-1 infectors. The detailed kinetic of HLA-B51-restricted CTL responses was described through blood sampling time points including seroconversion, 3 and 6 months after HIV-1 infection in the 7 HLA-B51+ individuals, by using 16 known HLA-B51 restricted epitopes. Pol743–751 (LPPVVAKEI, LI9), Pol283–289 (TAFTIPSI, TI8), and Gag327–3459 (NANPDCKTI, NI9) were identified as 3 dominant epitopes, and ranked as starting with LI9, followed by TI8 and NI9 in the ability to induce T-cell responses. The dynamics of escape mutations in the 3 epitopes were also found with the same order as T-cell response, by using sequencing for viral clones on blood sampling at seroconversion, 3 and 6 months after HIV-1 infection. We use solid evidence to demonstrate the correlation between T-cell response and HIV-1 mutation, and postulate that multiple T-cell responses might benefit the control of HIV-1 infection, especially in acute infection phase. PMID:27472741

  14. Analysis of T cell responses to the autoantigen in Goodpasture's disease.

    PubMed Central

    Derry, C J; Ross, C N; Lombardi, G; Mason, P D; Rees, A J; Lechler, R I; Pusey, C D

    1995-01-01

    Goodpasture's disease is a rare form of glomerulonephritis characterized by the production of autoantibodies to the glomerular basement membrane (GBM). In order to understand the development of autoimmunity to the GBM, it is important to examine mechanisms underlying T cell responses to the autoantigen. A MoAb P1, with the same specificity as patients' autoantibodies, was used to affinity-purify the antigen from collagenase-digested human GBM. This material was enriched in the NC1 domain of the alpha 3 chain of type IV collagen (alpha 3(IV)NC1), known to be the principal target of anti-GBM antibodies, but also contained lower quantities of alpha 4(IV)NC1. In proliferation assays, T cells from 11/14 patients with Goodpasture's disease showed significant responses (SI > or = 2.0) to affinity-purified human GBM. Peak responses were demonstrated at 7 or 10 days at antigen concentrations of 10-30 micrograms/ml. As in other autoimmune disorders, the presence of autoantigen-reactive T cells was also demonstrated in 5/10 healthy volunteers. Tissue typing revealed that all patients possessed HLA-DR2 and/or -DR4 alleles, while normal individuals whose T cells responded possessed DR2 and/or DR7 alleles. The specificity of the T cell response in Goodpasture's disease was further investigated using monomeric components of human GBM purified by gel filtration and reverse phase high performance liquid chromatography (HPLC). Two antigenic monomer pools were obtained, which were shown by amino-terminal sequence analysis to contain alpha 3(IV)NC1 and alpha 4(IV)NC1, respectively. In all patients tested, significant T cell proliferation was observed in response to one or both of these alpha (IV)NC1 domains. These results demonstrate that patients with Goodpasture's disease possess T cells reactive with autoantigens known to be recognized by anti-GBM antibodies. Images Fig. 2 PMID:7743665

  15. Age-associated Epstein–Barr virus-specific T cell responses in seropositive healthy adults

    PubMed Central

    Cárdenas Sierra, D; Vélez Colmenares, G; Orfao de Matos, A; Fiorentino Gómez, S; Quijano Gómez, S M

    2014-01-01

    Epstein–Barr virus (EBV) is present in 95% of the world's adult population. The immune response participates in immune vigilance and persistent infection control, and this condition is maintained by both a good quality (functionality) and quantity of specific T cells throughout life. In the present study, we evaluated EBV-specific CD4+ and CD8+ T lymphocyte responses in seropositive healthy individuals younger and older than 50 years of age. The assessment comprised the frequency, phenotype, functionality and clonotypic distribution of T lymphocytes. We found that in both age groups a similar EBV-specific T cell response was found, with overlapping numbers of tumour necrosis factor (TNF)-α+ T lymphocytes (CD4+ and CD8+) within the memory and effector cell compartments, in addition to monofunctional and multi-functional T cells producing interleukin (IL)-2 and/or interferon (IFN)-γ. However, individuals aged more than 50 years showed significantly higher frequencies of IL-2-producing CD4+ T lymphocytes in association with greater production of soluble IFN-γ, TNF-α and IL-6 than subjects younger than 50 years. A polyclonal T cell receptor (TCR)-variable beta region (Vβ) repertoire exists in both age groups under basal conditions and in response to EBV; the major TCR families found in TNF-α+/CD4+ T lymphocytes were Vβ1, Vβ2, Vβ17 and Vβ22 in both age groups, and the major TCR family in TNF-α+/CD8+ T cells was Vβ13·1 for individuals younger than 50 years and Vβ9 for individuals aged more than 50 years. Our findings suggest that the EBV-specific T cell response (using a polyclonal stimulation model) is distributed throughout several T cell differentiation compartments in an age-independent manner and includes both monofunctional and multi-functional T lymphocytes. PMID:24666437

  16. Characterisation of CD154+ T cells following ex vivo allergen stimulation illustrates distinct T cell responses to seasonal and perennial allergens in allergic and non-allergic individuals

    PubMed Central

    2013-01-01

    Background Allergic sensitisation has been ascribed to a dysregulated relationship between allergen-specific Th1, Th2 and regulatory T cells. We sought to utilise our short-term CD154 detection method to further analyse the relationship between these T cell subsets and investigate differences between seasonal and perennial allergens. Using peripheral blood samples from grass-allergic, cat-allergic and healthy non-atopic subjects, we compared the frequencies and phenotype of CD154-positive T helper cells following stimulation with seasonal (grass) and perennial (cat dander) allergens. Results We identified a higher frequency of CD154+ T cells in grass-allergic individuals compared to healthy controls; this difference was not evident following stimulation with cat allergen. Activated Th1, Th2 and Tr1-like cells, that co-express IFNγ, IL4 and IL10, respectively, were identified in varying proportions in grass-allergic, cat-allergic and non-allergic individuals. We confirmed a close correlation between Th1, Th2 and Tr1-like cell frequency in non-allergic volunteers, such that the three parameters increased together to maintain a low Th2: Th1 ratio. This relationship was dysregulated in grass-allergic individuals with no correlation between the T cell subsets and a higher Th2: Th1 ratio. We confirmed previous reports of a late-differentiated T cell phenotype in response to seasonal allergens compared to early-differentiated T cell responses to perennial allergens. Conclusions The findings confirm our existing work illustrating an important balance between Th1, Th2 and Tr1-like responses to allergens in health, where Th2 responses are frequently observed, but balanced by Th1 and regulatory responses. We confirm previous tetramer-based reports of phenotypic differences in T cells responding to seasonal and perennial allergens. PMID:24188324

  17. Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination

    SciTech Connect

    Korber, Bette; Fischer, William; Wallstrom, Timothy

    2009-01-01

    An effective AIDS vaccine must control highly diverse circulating strains of HIV-1. Among HIV -I gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV -I Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential Tcell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining (ICS) in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. I, 2 and 3 mosaic sets were developed that increased theoretical epitope coverage. The breadth and magnitude ofT-cell immunity stimulated by these vaccines were compared to natural strain Env's; additional comparisons were performed on mutant Env's, including gpl60 or gpl45 with or without V regions and gp41 deletions. Among them, the 2 or 3 mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the 3 mosaic set elicited responses to an average of 8 peptide pools compared to 2 pools for a set of3 natural Env's. Synthetic mosaic HIV -I antigens can therefore induce T-cell responses with expanded breadth and may facilitate the development of effective T -cell-based HIV -1 vaccines.

  18. Maximal T cell-mediated antitumor responses rely upon CCR5 expression in both CD4(+) and CD8(+) T cells.

    PubMed

    González-Martín, Alicia; Gómez, Lucio; Lustgarten, Joseph; Mira, Emilia; Mañes, Santos

    2011-08-15

    Immune responses against cancer rely upon leukocyte trafficking patterns that are coordinated by chemokines. CCR5, the receptor for chemotactic chemokines MIP1alpha, MIP1beta, and RANTES (CCL3, CCL4, CCL5), exerts major regulatory effects on CD4(+)- and CD8(+) T cell-mediated immunity. Although CCR5 and its ligands participate in the response to various pathogens, its relevance to tumoral immune control has been debated. Here, we report that CCR5 has a specific, ligand-dependent role in optimizing antitumor responses. In adoptive transfer studies, efficient tumor rejection required CCR5 expression by both CD4(+) and CD8(+) T cells. CCR5 activation in CD4(+) cells resulted in CD40L upregulation, leading to full maturation of antigen-presenting cells and enhanced CD8(+) T-cell crosspriming and tumor infiltration. CCR5 reduced chemical-induced fibrosarcoma incidence and growth, but did not affect the onset or progression of spontaneous breast cancers in tolerogenic Tg(MMTV-neu) mice. However, CCR5 was required for TLR9-mediated reactivation of antineu responses in these mice. Our results indicate that CCR5 boosts T-cell responses to tumors by modulating helper-dependent CD8(+) T-cell activation.

  19. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    PubMed Central

    Fogg, Mark; Murphy, John R.; Lorch, Jochen; Posner, Marshall; Wang, Fred

    2013-01-01

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. PMID:23601786

  20. Complexity of the primary genetic response to mitogenic activation of human T cells

    SciTech Connect

    Zipfel, P.F.; Siebenlist, U. ); Irving, S.G.; Kelly, K. )

    1989-03-01

    The authors describe the isolation and characterization of more than 60 novel cDNA clones that constitute part of the immediate genetic response to resting human peripheral blood T cells after mitogen activation. This primary response was highly complex, both in the absolute number of inducible genes and in the diversity of regulation. Although most of the genes expressed in activated T cells were shared with the activation response of normal human fibroblasts, a significant number were more restricted in tissue specificity and thus likely encode or effect the differentiated functions of activated T cells. The activatable genes could be further differentiated on the basis of kinetics of induction, response to cycloheximide, and sensitivity to the immunosuppressive drug cylcosporin A. It is of note that cyclosporin A inhibited the expression of more than 10 inducible genes, which suggests that this drug has a broad genetic mechanism of action.

  1. Characterization of CD4 and CD8 T Cell Responses in MuSK Myasthenia Gravis

    PubMed Central

    Yi, JS; Guidon, A; Sparks, S; Osborne, R; Juel, VC; Massey, JM; Sanders, DB; Weinhold, KJ; Guptill, JT

    2014-01-01

    Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T-cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T-cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T-cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T-cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T-cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T-cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in Treg function or number. PMID:24378287

  2. Characterization of CD4 and CD8 T cell responses in MuSK myasthenia gravis.

    PubMed

    Yi, J S; Guidon, A; Sparks, S; Osborne, R; Juel, V C; Massey, J M; Sanders, D B; Weinhold, K J; Guptill, J T

    2014-08-01

    Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in CD39 expression or Treg number.

  3. Polyfunctional HCV-specific T-cell responses are associated with effective control of HCV replication.

    PubMed

    Ciuffreda, Donatella; Comte, Denis; Cavassini, Matthias; Giostra, Emiliano; Bühler, Leo; Perruchoud, Monika; Heim, Markus H; Battegay, Manuel; Genné, Daniel; Mulhaupt, Beat; Malinverni, Raffaele; Oneta, Carl; Bernasconi, Enos; Monnat, Martine; Cerny, Andreas; Chuard, Christian; Borovicka, Jan; Mentha, Gilles; Pascual, Manuel; Gonvers, Jean-Jacques; Pantaleo, Giuseppe; Dutoit, Valérie

    2008-10-01

    HCV infection has a severe course of disease in HIV/HCV co-infection and in liver transplant recipients. However, the mechanisms involved remain unclear. Here, we evaluated functional profiles of HCV-specific T-cell responses in 86 HCV mono-infected patients, 48 HIV/HCV co-infected patients and 42 liver transplant recipients. IFN-gamma and IL-2 production and ability of CD4 and CD8 T cells to proliferate were assessed after stimulation with HCV-derived peptides. We observed that HCV-specific T-cell responses were polyfunctional in HCV mono-infected patients, with presence of proliferating single IL-2-, dual IL-2/IFN-gamma and single IFN-gamma-producing CD4+ and dual IL-2/IFN-gamma and single IFN-gamma-producing CD8+ cells. In contrast, HCV-specific T-cell responses had an effector profile in HIV/HCV co-infected individuals and liver transplant recipients with absence of single IL-2-producing HCV-specific CD4+ and dual IL-2/IFN-gamma-producing CD8+ T cells. In addition, HCV-specific proliferation of CD4+ and CD8+ T cells was severely impaired in HIV/HCV co-infected patients and liver transplant recipients. Importantly, "only effector" T-cell responses were associated with significantly higher HCV viral load and more severe liver fibrosis scores. Therefore, the present results suggest that immune-based mechanisms may contribute to explain the accelerated course of HCV infection in conditions of HIV-1 co-infection and liver transplantation.

  4. Memory T cell responses targeting the SARS coronavirus persist up to 11 years post-infection.

    PubMed

    Ng, Oi-Wing; Chia, Adeline; Tan, Anthony T; Jadi, Ramesh S; Leong, Hoe Nam; Bertoletti, Antonio; Tan, Yee-Joo

    2016-04-12

    Severe acute respiratory syndrome (SARS) is a highly contagious infectious disease which first emerged in late 2002, caused by a then novel human coronavirus, SARS coronavirus (SARS-CoV). The virus is believed to have originated from bats and transmitted to human through intermediate animals such as civet cats. The re-emergence of SARS-CoV remains a valid concern due to the continual persistence of zoonotic SARS-CoVs and SARS-like CoVs (SL-CoVs) in bat reservoirs. In this study, the screening for the presence of SARS-specific T cells in a cohort of three SARS-recovered individuals at 9 and 11 years post-infection was carried out, and all memory T cell responses detected target the SARS-CoV structural proteins. Two CD8(+) T cell responses targeting the SARS-CoV membrane (M) and nucleocapsid (N) proteins were characterized by determining their HLA restriction and minimal T cell epitope regions. Furthermore, these responses were found to persist up to 11 years post-infection. An absence of cross-reactivity of these CD8(+) T cell responses against the newly-emerged Middle East respiratory syndrome coronavirus (MERS-CoV) was also demonstrated. The knowledge of the persistence of SARS-specific celullar immunity targeting the viral structural proteins in SARS-recovered individuals is important in the design and development of SARS vaccines, which are currently unavailable.

  5. Adaptive Memory of Human NK-like CD8+ T-Cells to Aging, and Viral and Tumor Antigens

    PubMed Central

    Pita-López, María Luisa; Pera, Alejandra; Solana, Rafael

    2016-01-01

    Human natural killer (NK)-like CD8+ T-cells are singular T-cells that express both T and NK cell markers such as CD56; their frequencies depend on their differentiation and activation during their lifetime. There is evidence of the presence of these innate CD8+ T-cells in the human umbilical cord, highlighting the necessity of investigating whether the NK-like CD8+ T-cells arise in the early stages of life (gestation). Based on the presence of cell surface markers, these cells have also been referred to as CD8+KIR+ T-cells, innate CD8+ T-cells, CD8+CD28−KIR+ T-cells or NKT-like CD8+CD56+ cells. However, the functional and co-signaling significance of these NK cell receptors on NK-like CD8+ T-cells is less clear. Also, the diverse array of costimulatory and co-inhibitory receptors are spatially and temporally regulated and may have distinct overlapping functions on NK-like CD8+ T-cell priming, activation, differentiation, and memory responses associated with different cell phenotypes. Currently, there is no consensus regarding the functional properties and phenotypic characterization of human NK-like CD8+ T-cells. Environmental factors, such as aging, autoimmunity, inflammation, viral antigen re-exposure, or the presence of persistent tumor antigens have been shown to allow differentiation (“adaptation”) of the NK-like CD8+ T-cells; the elucidation of this differentiation process and a greater understanding of the characteristics of these cells could be important for their eventual in potential therapeutic applications aimed at improving protective immunity. This review will attempt to elucidate an understanding of the characteristics of these cells with the goal toward their eventual use in potential therapeutic applications aimed at improving protective immunity. PMID:28066426

  6. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses.

    PubMed

    Shorter, Shayla K; Schnell, Frederick J; McMaster, Sean R; Pinelli, David F; Andargachew, Rakieb; Evavold, Brian D

    2016-01-01

    T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC) or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL), have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV) escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4) are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant.

  7. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses

    PubMed Central

    Shorter, Shayla K.; Schnell, Frederick J.; McMaster, Sean R.; Pinelli, David F.; Andargachew, Rakieb; Evavold, Brian D.

    2016-01-01

    T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC) or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL), have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV) escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4) are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant. PMID:26915099

  8. Rituximab Therapy Reduces Organ-Specific T Cell Responses and Ameliorates Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Monson, Nancy L.; Cravens, Petra; Hussain, Rehana; Harp, Christopher T.; Cummings, Matthew; de Pilar Martin, Maria; Ben, Li-Hong; Do, Julie; Lyons, Jeri-Anne; Lovette-Racke, Amy; Cross, Anne H.; Racke, Michael K.; Stüve, Olaf; Shlomchik, Mark; Eagar, Todd N.

    2011-01-01

    Recent clinical trials have established B cell depletion by the anti-CD20 chimeric antibody Rituximab as a beneficial therapy for patients with relapsing-remitting multiple sclerosis (MS). The impact of Rituximab on T cell responses remains largely unexplored. In the experimental autoimmune encephalomyelitis (EAE) model of MS in mice that express human CD20, Rituximab administration rapidly depleted peripheral B cells and strongly reduced EAE severity. B cell depletion was also associated with diminished Delayed Type Hypersensitivity (DTH) and a reduction in T cell proliferation and IL-17 production during recall immune response experiments. While Rituximab is not considered a broad immunosuppressant, our results indicate a role for B cells as a therapeutic cellular target in regulating encephalitogenic T cell responses in specific tissues. PMID:21359213

  9. Complement modulation of T cell immune responses during homeostasis and disease.

    PubMed

    Clarke, Elizabeth V; Tenner, Andrea J

    2014-11-01

    The complement system is an ancient and critical effector mechanism of the innate immune system as it senses, kills, and clears infectious and/or dangerous particles and alerts the immune system to the presence of the infection and/or danger. Interestingly, an increasing number of reports have demonstrated a clear role for complement in the adaptive immune system as well. Of note, a number of recent studies have identified previously unknown roles for complement proteins, receptors, and regulators in T cell function. Here, we will review recent data demonstrating the influence of complement proteins C1q, C3b/iC3b, C3a (and C3aR), and C5a (and C5aR) and complement regulators DAF (CD55) and CD46 (MCP) on T cell function during homeostasis and disease. Although new concepts are beginning to emerge in the field of complement regulation of T cell function, future experiments should focus on whether complement is interacting directly with the T cell or is having an indirect effect on T cell function via APCs, the cytokine milieu, or downstream complement activation products. Importantly, the identification of the pivotal molecular pathways in the human systems will be beneficial in the translation of concepts derived from model systems to therapeutic targeting for treatment of human disorders.

  10. The humoral response in TCR alpha-/- mice. Can gammadelta-T cells support the humoral immune response?

    PubMed

    Lindroth, K; Troye-Blomberg, M; Singh, M; Dieli, F; Ivanyi, J; Fernández, C

    2002-03-01

    An optimal humoral response requires T-cell help; however, it has been questioned if this help comes exclusively from alphabeta-T cells or whether gammadelta-T cells also contribute. We have attempted to answer this question by studying the humoral response in T-cell receptor alpha-chain knockout (alpha-/-) mice, which lack the alphabetaT cell subset. Two model antigens were used to characterize the response: the thymus-independent (TI) antigen native dextran B512 (Dx), and the thymus-dependent (TD) antigen heat shock protein (HSP65) from Mycobacterium tuberculosis. When challenged with Dx, the alpha-/- mice elicited a strong antibody response and formed rudimentary germinal centres (GCs), a T-cell dependent reaction. In contrast, the humoral response to HSP65 was poor. However, alpha-/- mice became primed when challenged with HSP65, because when supplemented with wild-type thymocytes, the antigen-primed animals were able to mount a stronger response than the nonprimed ones when challenged with HSP65. A crucial step seems to be the collaboration between gammadeltaT cells and antigen presenting cells (APCs), as splenocytes from alpha-/- mice were able to respond to HSP65 in an environment containing primed-APCs. Based on these results, we propose a model for B-cell activation in the alpha-/- mice.

  11. Effector and memory T cell subsets in the response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14 days) cultured IFN-gamma ELISPOT assays of peripheral blood mononuclear cells (PBMC) are used to access T cell central memory (Tcm) responses in both cattle and humans. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT response correlates with protection; how...

  12. Effector and memory T cell subsets in the response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14d) cultured IFN-gamma ELISPOT assays of PBMC are used as a correlate of T cell central memory (Tcm) responses in cattle and humans. With bovine tuberculosis, vaccine-elicited Tcm responses correlate with protection against experimental Mycobacterium bovis infection. The objective ...

  13. Bovine central memory T cells are highly proliferative in response to bovine tuberculosis infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14 days) cultured IFN-gamma ELISPOT assays measure central memory T cell (Tcm) responses in both humans and cattle. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT responses correlate with protection. In other species, Tcm’s pose low activation threshold and a...

  14. Bovine central memory T cells are highly proliferative in response to bovine tuberculosis infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term (i.e., 14 days) cultured IFN-gamma responses of peripheral blood mononuclear cells are used as a correlate of T cell central memory (Tcm) responses in both humans and cattle. With bovine tuberculosis, vaccine-elicited long-term IFN-gamma ELISPOT assays are a correlate of protection. Recent...

  15. Self-recognition specificity expressed by T cells from nude mice. Absence of detectable Ia-restricted T cells in nude mice that do exhibit self-K/D-restricted T cell responses

    SciTech Connect

    Kruisbeek, A.M.; Davis, M.L.; Matis, L.A.; Longo, D.L.

    1984-09-01

    The presence in athymic nude mice of precursor T cells with self-recognition specificity for either H-2 K/D or H-2 I region determinants was investigated. Chimeras were constructed of lethally irradiated parental mice receiving a mixture of F1 nude mouse (6-8 wk old) spleen and bone marrow cells. The donor inoculum was deliberately not subjected to any T cell depletion procedure, so that any potential major histocompatibility complex-committed precursor T cells were allowed to differentiate and expand in the normal parental recipients. 3 mo after reconstitution, the chimeras were immunized with several protein antigens in complete Freund's adjuvant in the footpads and their purified draining lymph node T cells tested 10 d later for ability to recognize antigen on antigen-presenting cells of either parental haplotype. Also, their spleen and lymph node cells were tested for ability to generate a cytotoxic T lymphocyte (CTL) response to trinitrophenyl (TNP)-modified stimulator cells of either parental haplotype. It was demonstrated that T cell proliferative responses of these F1(nude)----parent chimeras were restricted solely to recognizing parental host I region determinants as self and expressed the Ir gene phenotype of the host. In contrast, CTL responses could be generated (in the presence of interleukin 2) to TNP-modified stimulator cells of either parental haplotype. Thus these results indicate that nude mice which do have CTL with self-specificity for K/D region determinants lack proliferating T cells with self-specificity for I region determinants. These results provide evidence for the concepts that development of the I region-restricted T cell repertoire is strictly an intrathymically determined event and that young nude mice lack the unique thymic elements responsible for edu

  16. Cell-mediated responses of immunized vervet monkeys to defined Leishmania T-cell epitopes.

    PubMed Central

    Curry, A J; Jardim, A; Olobo, J O; Olafson, R W

    1994-01-01

    A population of vervet monkeys was immunized with killed parasites and infected with Leishmania major promastigotes either by needle or by infected-fly bite. The responses of recovered monkeys to mitogens, killed parasites, and molecularly defined T-cell epitopes were then compared with those of control animals. Peripheral blood mononuclear cells (PBMC) from both naive and recovered animals proliferated strongly in response to both B- and T-cell mitogens, although the responses of the recovered animals were less strong than those of the naive animals. Cells from recovered vervets, but not those from naive vervets, also proliferated in response to parasite antigens and synthetic T-cell epitopes. Likewise, cells from recovered animals released gamma interferon and either interleukin 2 (IL-2) or IL-4 into culture media in response to both of the above-mentioned antigens, whereas cells from control animals did not. The fact that no IL-5 could be measured following parasite antigen or synthetic T-cell epitope stimulation of PBMC suggested that cells proliferating in response to these molecules belonged to the Th1 subset. Phenotypic analysis of the PBMC showed a marked increase in T-cell but not B-cell populations in recovered animals. Among this population was an increased number of CD45R0+ memory cells. The data from this study are in keeping with the earlier finding that vervet monkeys provide an excellent model system for leishmaniasis. Further, these data support the contention that synthetic T-cell epitopes are prime candidates for molecularly defined Leishmania vaccines. PMID:7513306

  17. Stronger hepatitis C virus-specific CD8+ T-cell responses in HIV coinfection.

    PubMed

    Barrett, L; Gallant, M; Howley, C; Ian Bowmer, M; Hirsch, G; Peltekian, K; Grant, M

    2011-03-01

    Hepatitis C virus (HCV) is a widespread chronic infection that shares routes of transmission with human immunodeficiency virus (HIV). Thus, coinfection with these viruses is a relatively common and growing problem. In general, liver disease develops over years with HIV coinfection, when compared to decades in HCV monoinfection. The role of the immune system in the accelerated pathogenesis of liver disease in HIV/HCV coinfection is not clear. In this study, we compared the frequency, magnitude, breadth and specificity of peripheral blood CD4+ and CD8+ T-cell responses between HCV-monoinfected and HCV/HIV-coinfected individuals and between HIV/HCV-coinfected subgroups distinguished by anti-HCV antibody and HCV RNA status. While HIV coinfection tended to reduce the frequency and breadth of anti-HCV CD8+ T-cell responses in general, responses that were present were substantially stronger than in monoinfection. In all groups, HCV-specific CD4+ T-cell responses were rare and weak, independent of either nadir or concurrent CD4+ T-cell counts of HIV-infected individuals. Subgroup analysis demonstrated restricted breadth of CD8+ HCV-specific T-cell responses and lower B-cell counts in HIV/HCV-coinfected individuals without anti-HCV antibodies. The greatest difference between HIV/HCV-coinfected and HCV-monoinfected groups was substantially stronger HCV-specific CD8+ T-cell responses in the HIV-coinfected group, which may relate to accelerated liver disease in this setting.

  18. Regulatory effect of monocytes on T cell proliferative responses to oral microbial antigens.

    PubMed Central

    Stashenko, P

    1982-01-01

    Mononuclear cell preparations isolated by Ficoll-Hypaque centrifugation from human peripheral blood were found to vary considerably in the number of monocytes they contained (mean, 20.3%; range, 13 to 33%). The regulatory role of monocytes in T cell proliferative responses to sonic extracts of a panel of oral microorganisms was therefore investigated. T cells were fractionated by anti-immunoglobulin chromatography and depleted of monocytes by treatment with a monoclonal anti-human Ia-like (DR locus antigen) antibody and complement. Purified populations of monocytes were obtained by extensive adherence procedures. The resultant cell populations were greater than 95% pure, as judged by indirect immunofluorescence on a fluorescence-activated cell sorter. Monocyte-depleted T cells failed to respond by proliferation to the nonoral antigen tetanus toxoid, as well as to any oral microorganism, but retained responsiveness to phytohemagglutinin. Readdition of monocytes in final concentrations of from 5 to 15% resulted in the restoration of maximal T cell proliferation. Monocytes in greater numbers suppressed T cell responses to all sonic extracts tested. PMID:6984019

  19. Suppression by thimerosal of ex-vivo CD4+ T cell response to influenza vaccine and induction of apoptosis in primary memory T cells.

    PubMed

    Loison, Emily; Poirier-Beaudouin, Béatrice; Seffer, Valérie; Paoletti, Audrey; Abitbol, Vered; Tartour, Eric; Launay, Odile; Gougeon, Marie-Lise

    2014-01-01

    Thimerosal is a preservative used widely in vaccine formulations to prevent bacterial and fungal contamination in multidose vials of vaccine. Thimerosal was included in the multidose non-adjuvanted pandemic 2009 H1N1 vaccine Panenza. In the context of the analysis of the ex-vivo T cell responses directed against influenza vaccine, we discovered the in vitro toxicity Panenza, due to its content in thimerosal. Because thimerosal may skew the immune response to vaccines, we investigated in detail the ex-vivo effects of thimerosal on the fate and functions of T cells in response to TCR ligation. We report that ex-vivo exposure of quiescent or TCR-activated primary human T cells to thimerosal induced a dose-dependent apoptotic cell death associated with depolarization of mitochondrial membrane, generation of reactive oxygen species, cytochrome c release from the mitochondria and caspase-3 activation. Moreover, exposure to non-toxic concentrations of thimerosal induced cell cycle arrest in G0/G1 phase of TCR-activated T cells, and inhibition of the release of proinflammatory cytokines such as IFN gamma, IL-1 beta, TNF alpha, IL-2, as well as the chemokine MCP1. No shift towards Th2 or Th17 cells was detected. Overall these results underline the proapoptotic effect of thimerosal on primary human lymphocytes at concentrations 100 times less to those contained in the multidose vaccine, and they reveal the inhibitory effect of this preservative on T-cell proliferation and functions at nanomolar concentrations.

  20. Metal-specific CD4+ T-cell responses induced by beryllium exposure in HLA-DP2 transgenic mice.

    PubMed

    Falta, M T; Tinega, A N; Mack, D G; Bowerman, N A; Crawford, F; Kappler, J W; Pinilla, C; Fontenot, A P

    2016-01-01

    Chronic beryllium disease (CBD) is a granulomatous lung disorder that is associated with the accumulation of beryllium (Be)-specific CD4(+) T cells into the lung. Genetic susceptibility is linked to HLA-DPB1 alleles that possess a glutamic acid at position 69 (βGlu69), and HLA-DPB1*02:01 is the most prevalent βGlu69-containing allele. Using HLA-DP2 transgenic (Tg) mice, we developed a model of CBD that replicates the major features of the human disease. Here we characterized the T-cell receptor (TCR) repertoire of Be-responsive CD4(+) T cells derived from the lungs of Be oxide-exposed HLA-DP2 Tg mice. The majority of Be-specific T-cell hybridomas expressed TCR Vβ6, and a subset of these hybridomas expressed identical or nearly identical β-chains that were paired with different α-chains. We delineated mimotopes that bind to HLA-DP2 and form a complex recognized by Be-specific CD4(+) T cells in the absence of Be. These Be-independent peptides possess an arginine at p5 and a tryptophan at p7 that surround the Be-binding site within the HLA-DP2 acidic pocket and likely induce charge and conformational changes that mimic those induced by the Be(2+) cation. Collectively, these data highlight the interplay between peptides and Be in the generation of an adaptive immune response in metal-induced hypersensitivity.

  1. Metal-specific CD4+ T cell responses induced by beryllium exposure in HLA-DP2 transgenic mice

    PubMed Central

    Falta, Michael T.; Tinega, Alex N.; Mack, Douglas G.; Bowerman, Natalie A.; Crawford, Frances; Kappler, John W.; Pinilla, Clemencia; Fontenot, Andrew P.

    2015-01-01

    Chronic beryllium disease (CBD) is a granulomatous lung disorder that is associated with the accumulation of beryllium (Be)-specific CD4+ T cells into the lung. Genetic susceptibility is linked to HLA-DPB1 alleles that possess a glutamic acid at position 69 (βGlu69), and HLA-DPB1*02:01 is the most prevalent βGlu69-containing allele. Using HLA-DP2 transgenic (Tg) mice, we developed a model of CBD that replicates the major features of the human disease. Here, we characterized the T cell receptor repertoire of Be-responsive CD4+ T cells derived from the lungs of Be oxide-exposed HLA-DP2 Tg mice. The majority of Be-specific T cell hybridomas expressed TCR Vβ6, and a subset of these hybridomas expressed identical or nearly identical β-chains that were paired with different α-chains. We delineated mimotopes that bind to HLA-DP2 and form a complex recognized by Be-specific CD4+ T cells in the absence of Be. These Be-independent peptides possess an arginine at p5 and a tryptophan at p7 that surround the Be-binding site within the HLA-DP2 acidic pocket and likely induce charge and conformational changes that mimic those induced by the Be2+ cation. Collectively, these data highlight the interplay between peptides and Be in the generation of an adaptive immune response in metal-induced hypersensitivity. PMID:26129650

  2. Distribution of T Cells in Rainbow Trout (Oncorhynchus mykiss) Skin and Responsiveness to Viral Infection

    PubMed Central

    Leal, Esther; Granja, Aitor G.; Zarza, Carlos; Tafalla, Carolina

    2016-01-01

    Although the skin constitutes the first line of defense against waterborne pathogens, there is a great lack of information regarding the skin associated lymphoid tissue (SALT) and whether immune components of the skin are homogeneously distributed through the surface of the fish is still unknown. In the current work, we have analyzed the transcription of several immune genes throughout different rainbow trout (Oncorhynchus mykiss) skin areas. We found that immunoglobulin and chemokine gene transcription levels were higher in a skin area close to the gills. Furthermore, this skin area as well as other anterior sections also transcribed significantly higher levels of many different immune genes related to T cell immunity such as T cell receptor α (TCRα), TCRγ, CD3, CD4, CD8, perforin, GATA3, Tbet, FoxP3, interferon γ (IFNγ), CD40L and Eomes in comparison to posterior skin sections. In agreement with these results, immunohistochemical analysis revealed that anterior skin areas had a higher concentration of CD3+ T cells and flow cytometry analysis confirmed that the percentage of CD8+ T lymphocytes was also higher in anterior skin sections. These results demonstrate for the first time that T cells are not homogeneously distributed throughout the teleost skin. Additionally, we studied the transcriptional regulation of these and additional T cell markers in response to a bath infection with viral hemorrhagic septicemia virus (VHSV). We found that VHSV regulated the transcription of several of these T cell markers in both the skin and the spleen; with some differences between anterior and posterior skin sections. Altogether, our results point to skin T cells as major players of teleost skin immunity in response to waterborne viral infections. PMID:26808410

  3. Norovirus-Specific Memory T Cell Responses in Adult Human Donors

    PubMed Central

    Malm, Maria; Tamminen, Kirsi; Vesikari, Timo; Blazevic, Vesna

    2016-01-01

    Norovirus (NoV) is a leading cause of acute gastroenteritis in people of all ages worldwide. NoV-specific serum antibodies which block the binding of NoV virus-like particles (VLPs) to the cell receptors have been thoroughly investigated. In contrast, only a few publications are available on the NoV capsid VP1 protein-specific T cell responses in humans naturally infected with the virus. Freshly isolated peripheral blood mononuclear cells of eight healthy adult human donors previously exposed to NoV were stimulated with purified VLPs derived from NoV GII.4-1999, GII.4-2012 (Sydney), and GI.3, and IFN-γ production was measured by an ELISPOT assay. In addition, 76 overlapping synthetic peptides spanning the entire 539-amino acid sequence of GII.4 VP1 were pooled into two-dimensional matrices and used to identify putative T cell epitopes. Seven of the eight subjects produced IFN-γ in response to the peptides and five subjects produced IFN-γ in response to the VLPs of the same origin. In general, stronger T cell responses were induced with the peptides in each donor compared to the VLPs. A CD8+ T cell epitope in the shell domain of the VP1 (134SPSQVTMFPHIIVDVRQL151) was identified in two subjects, both having human leukocyte antigen (HLA)-A∗02:01 allele. To our knowledge, this is the first report using synthetic peptides to study NoV-specific T cell responses in human subjects and identify T cell epitopes. PMID:27752254

  4. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia.

    PubMed

    Saghaug, Christina Skår; Sørnes, Steinar; Peirasmaki, Dimitra; Svärd, Staffan; Langeland, Nina; Hanevik, Kurt

    2015-09-16

    The intestinal protozoan parasite Giardia lamblia may cause severe prolonged diarrheal disease or pass unnoticed as an asymptomatic infection. T cells seem to play an important role in the immune response to Giardia infection, and memory responses may last years. Recently, TH17 responses have been found in three animal studies of Giardia infection. The aim of this study was to characterize the human CD4(+) T cell responses to Giardia. Peripheral blood mononuclear cells (PBMCs) were obtained from 21 returning travelers with recent or ongoing giardiasis and 12 low-risk healthy controls and stimulated in vitro with Giardia lamblia proteins. Production of tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-17A (IL-17A), IL-10, and IL-4 was measured in CD4(+) effector memory (EM) T cells after 24 h by flow cytometry. After 6 days of culture, activation and proliferation were measured by flow cytometry, while an array of inflammatory cytokine levels in supernatants were measured with multiplex assays. We found the number of IL-17A-producing CD4(+) EM T cells, as well as that of cells simultaneously producing both IL-17A and TNF-α, to be significantly elevated in the Giardia-exposed individuals after 24 h of antigen stimulation. In supernatants of PBMCs stimulated with Giardia antigens for 6 days, we found inflammation-associated cytokines, including 1L-17A, as well as CD4(+) T cell activation and proliferation, to be significantly elevated in the Giardia-exposed individuals. We conclude that symptomatic Giardia infection in humans induces a CD4(+) EM T cell response of which IL-17A production seems to be an important component.

  5. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia

    PubMed Central

    Sørnes, Steinar; Peirasmaki, Dimitra; Svärd, Staffan; Langeland, Nina

    2015-01-01

    The intestinal protozoan parasite Giardia lamblia may cause severe prolonged diarrheal disease or pass unnoticed as an asymptomatic infection. T cells seem to play an important role in the immune response to Giardia infection, and memory responses may last years. Recently, TH17 responses have been found in three animal studies of Giardia infection. The aim of this study was to characterize the human CD4+ T cell responses to Giardia. Peripheral blood mononuclear cells (PBMCs) were obtained from 21 returning travelers with recent or ongoing giardiasis and 12 low-risk healthy controls and stimulated in vitro with Giardia lamblia proteins. Production of tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-17A (IL-17A), IL-10, and IL-4 was measured in CD4+ effector memory (EM) T cells after 24 h by flow cytometry. After 6 days of culture, activation and proliferation were measured by flow cytometry, while an array of inflammatory cytokine levels in supernatants were measured with multiplex assays. We found the number of IL-17A-producing CD4+ EM T cells, as well as that of cells simultaneously producing both IL-17A and TNF-α, to be significantly elevated in the Giardia-exposed individuals after 24 h of antigen stimulation. In supernatants of PBMCs stimulated with Giardia antigens for 6 days, we found inflammation-associated cytokines, including 1L-17A, as well as CD4+ T cell activation and proliferation, to be significantly elevated in the Giardia-exposed individuals. We conclude that symptomatic Giardia infection in humans induces a CD4+ EM T cell response of which IL-17A production seems to be an important component. PMID:26376930

  6. Multiplexed Nanoplasmonic Temporal Profiling of T-Cell Response under Immunomodulatory Agent Exposure

    PubMed Central

    2016-01-01

    Immunomodulatory drugs—agents regulating the immune response—are commonly used for treating immune system disorders and minimizing graft versus host disease in persons receiving organ transplants. At the cellular level, immunosuppressant drugs are used to inhibit pro-inflammatory or tissue-damaging responses of cells. However, few studies have so far precisely characterized the cellular-level effect of immunomodulatory treatment. The primary challenge arises due to the rapid and transient nature of T-cell immune responses to such treatment. T-cell responses involve a highly interactive network of different types of cytokines, which makes precise monitoring of drug-modulated T-cell response difficult. Here, we present a nanoplasmonic biosensing approach to quantitatively characterize cytokine secretion behaviors of T cells with a fine time-resolution (every 10 min) that are altered by an immunosuppressive drug used in the treatment of T-cell-mediated diseases. With a microfluidic platform integrating antibody-conjugated gold nanorod (AuNR) arrays, the technique enables simultaneous multi-time-point measurements of pro-inflammatory (IL-2, IFN-γ, and TNF-α) and anti-inflammatory (IL-10) cytokines secreted by T cells. The integrated nanoplasmonic biosensors achieve precise measurements with low operating sample volume (1 μL), short assay time (∼30 min), heightened sensitivity (∼20–30 pg/mL), and negligible sensor crosstalk. Data obtained from the multicytokine secretion profiles with high practicality resulting from all of these sensing capabilities provide a comprehensive picture of the time-varying cellular functional state during pharmacologic immunosuppression. The capability to monitor cellular functional response demonstrated in this study has great potential to ultimately permit personalized immunomodulatory treatment. PMID:27478873

  7. Early Gag Immunodominance of the HIV-Specific T-Cell Response during Acute/Early Infection Is Associated with Higher CD8+ T-Cell Antiviral Activity and Correlates with Preservation of the CD4+ T-Cell Compartment

    PubMed Central

    Ghiglione, Yanina; Falivene, Juliana; Socias, María Eugenia; Laufer, Natalia; Coloccini, Romina Soledad; Rodriguez, Ana María; Ruiz, María Julia; Pando, María Ángeles; Giavedoni, Luis David; Cahn, Pedro; Sued, Omar; Salomon, Horacio; Gherardi, María Magdalena

    2013-01-01

    The important role of the CD8+ T-cell response on HIV control is well established. Moreover, the acute phase of infection represents a proper scenario to delineate the antiviral cellular functions that best correlate with control. Here, multiple functional aspects (specificity, ex vivo viral inhibitory activity [VIA] and polyfunctionality) of the HIV-specific CD8+ T-cell subset arising early after infection, and their association with disease progression markers, were examined. Blood samples from 44 subjects recruited within 6 months from infection (primary HIV infection [PHI] group), 16 chronically infected subjects, 11 elite controllers (EC), and 10 healthy donors were obtained. Results indicated that, although Nef dominated the anti-HIV response during acute/early infection, a higher proportion of early anti-Gag T cells correlated with delayed progression. Polyfunctional HIV-specific CD8+ T cells were detected at early time points but did not associate with virus control. Conversely, higher CD4+ T-cell set points were observed in PHI subjects with higher HIV-specific CD8+ T-cell VIA at baseline. Importantly, VIA levels correlated with the magnitude of the anti-Gag cellular response. The advantage of Gag-specific cells may result from their enhanced ability to mediate lysis of infected cells (evidenced by a higher capacity to degranulate and to mediate VIA) and to simultaneously produce IFN-γ. Finally, Gag immunodominance was associated with elevated plasma levels of interleukin 2 (IL-2) and macrophage inflammatory protein 1β (MIP-1β). All together, this study underscores the importance of CD8+ T-cell specificity in the improved control of disease progression, which was related to the capacity of Gag-specific cells to mediate both lytic and nonlytic antiviral mechanisms at early time points postinfection. PMID:23616666

  8. Adoptive transfer of tracer alloreactive CD4(+) TCR-transgenic T cells alters the endogenous immune response to an allograft.

    PubMed

    Miller, Michelle L; Chen, Jianjun; Daniels, Melvin D; McKeague, Matthew G; Wang, Ying; Yin, Dengping; Vu, Vinh; Chong, Anita S; Alegre, Maria-Luisa

    2016-04-11

    T cell receptor transgenic (TCR-Tg) T cells are often used as tracer populations of antigen-specific responses to extrapolate findings to endogenous T cells. The extent to which TCR-Tg T cells behave purely as tracer cells or modify the endogenous immune response is not clear. To test the impact of TCR-Tg T cell transfer on endogenous alloimmunity, recipient mice were seeded with CD4(+) or CD8(+) TCR-Tg or polyclonal T cells at the time of cardiac allograft transplantation. Only CD4(+) TCR-Tg T cells accelerated rejection, and unexpectedly led to a dose-dependent decrease in both transferred and endogenous T cells infiltrating the graft. In contrast, recipients of CD4(+) TCR-Tg cell exhibited enhanced endogenous donor-specific CD8(+) T-cell activation in the spleen and accelerated alloantibody production. Introduction of CD4(+) TCR-Tg T cells also perturbed the intra-graft accumulation of innate cell populations. Thus, transferred CD4(+) TCR-Tg T cells alter many aspects of endogenous alloimmunity, suggesting that caution should be used when interpreting experiments utilizing these adoptively-transferred cells, as the overall nature of allograft rejection may be altered. These results may also have implications for adoptive CD4(+) T cell immunotherapy in tumor and infectious clinical settings as cell infusion may have additional effects on natural immune responses. This article is protected by copyright. All rights reserved.

  9. The CD8 T-cell response during tolerance induction in liver transplantation

    PubMed Central

    Wong, Yik Chun; McCaughan, Geoffrey W; Bowen, David G; Bertolino, Patrick

    2016-01-01

    Both experimental and clinical studies have shown that the liver possesses unique tolerogenic properties. Liver allografts can be spontaneously accepted across complete major histocompatibility mismatch in some animal models. In addition, some liver transplant patients can be successfully withdrawn from immunosuppressive medications, developing ‘operational tolerance'. Multiple mechanisms have been shown to be involved in inducing and maintaining alloimmune tolerance associated with liver transplantation. Here, we focus on CD8 T-cell tolerance in this setting. We first discuss how alloreactive cytotoxic T-cell responses are generated against allografts, before reviewing how the liver parenchyma, donor passenger leucocytes and the host immune system function together to attenuate alloreactive CD8 T-cell responses to promote the long-term survival of liver transplants. PMID:27867515

  10. T-cell modulatory properties of CD5 and its role in antitumor immune responses

    PubMed Central

    Tabbekh, Mouna; Mokrani-Hammani, M’Barka; Bismuth, Georges; Mami-Chouaib, Fathia

    2013-01-01

    The destruction of tumor cells by the immune system is under the control of positive and negative receptors that tightly regulate T-cell effector functions. The T-cell receptor (TCR) inhibitory molecule CD5 critically contributes to the regulation of antitumor immune responses. Indeed, the modulation of CD5 within the tumor microenvironment corresponds to a strategy adopted by tumor-specific cytotoxic T lymphocytes (CTLs) to optimize their cytotoxic and cytokine secretion functions. In this review, we provide insights into the immunobiology of CD5 and its role in regulating antitumor CD8 T-cell responses, and suggest the possibility of targeting CD5 to improve the efficacy of current immunotherapeutic approaches against cancer. PMID:23483035

  11. Detecting Antigen-Specific T Cell Responses: From Bulk Populations to Single Cells.

    PubMed

    Phetsouphanh, Chansavath; Zaunders, John James; Kelleher, Anthony Dominic

    2015-08-12

    A new generation of sensitive T cell-based assays facilitates the direct quantitation and characterization of antigen-specific T cell responses. Single-cell analyses have focused on measuring the quality and breadth of a response. Accumulating data from these studies demonstrate that there is considerable, previously-unrecognized, heterogeneity. Standard assays, such as the ICS, are often insufficient for characterization of rare subsets of cells. Enhanced flow cytometry with imaging capabilities enables the determination of cell morphology, as well as the spatial localization of the protein molecules within a single cell. Advances in both microfluidics and digital PCR have improved the efficiency of single-cell sorting and allowed multiplexed gene detection at the single-cell level. Delving further into the transcriptome of single-cells using RNA-seq is likely to reveal the fine-specificity of cellular events such as alternative splicing (i.e., splice variants) and allele-specific expression, and will also define the roles of new genes. Finally, detailed analysis of clonally related antigen-specific T cells using single-cell TCR RNA-seq will provide information on pathways of differentiation of memory T cells. With these state of the art technologies the transcriptomics and genomics of Ag-specific T cells can be more definitively elucidated.

  12. Otud7b facilitates T cell activation and inflammatory responses by regulating Zap70 ubiquitination.

    PubMed

    Hu, Hongbo; Wang, Hui; Xiao, Yichuan; Jin, Jin; Chang, Jae-Hoon; Zou, Qiang; Xie, Xiaoping; Cheng, Xuhong; Sun, Shao-Cong

    2016-03-07

    Signal transduction from the T cell receptor (TCR) is crucial for T cell-mediated immune responses and, when deregulated, also contributes to the development of autoimmunity. How TCR signaling is regulated is incompletely understood. In this study, we demonstrate a ubiquitin-dependent mechanism in which the deubiquitinase Otud7b has a crucial role in facilitating TCR signaling. Upon TCR ligation, Otud7b is rapidly recruited to the tyrosine kinase Zap70, a central mediator of TCR-proximal signaling. Otud7b deficiency attenuates the activation of Zap70 and its downstream pathways and impairs T cell activation and differentiation, rendering mice refractory to T cell-mediated autoimmune and inflammatory responses. Otud7b facilitated Zap70 activation by deubiquitinating Zap70, thus preventing the association of Zap70 with the negative-regulatory phosphatases Sts1 and Sts2. These findings establish Otud7b as a positive regulator of TCR-proximal signaling and T cell activation, highlighting the importance of deubiquitination in regulating Zap70 function.

  13. Detecting Antigen-Specific T Cell Responses: From Bulk Populations to Single Cells

    PubMed Central

    Phetsouphanh, Chansavath; Zaunders, John James; Kelleher, Anthony Dominic

    2015-01-01

    A new generation of sensitive T cell-based assays facilitates the direct quantitation and characterization of antigen-specific T cell responses. Single-cell analyses have focused on measuring the quality and breadth of a response. Accumulating data from these studies demonstrate that there is considerable, previously-unrecognized, heterogeneity. Standard assays, such as the ICS, are often insufficient for characterization of rare subsets of cells. Enhanced flow cytometry with imaging capabilities enables the determination of cell morphology, as well as the spatial localization of the protein molecules within a single cell. Advances in both microfluidics and digital PCR have improved the efficiency of single-cell sorting and allowed multiplexed gene detection at the single-cell level. Delving further into the transcriptome of single-cells using RNA-seq is likely to reveal the fine-specificity of cellular events such as alternative splicing (i.e., splice variants) and allele-specific expression, and will also define the roles of new genes. Finally, detailed analysis of clonally related antigen-specific T cells using single-cell TCR RNA-seq will provide information on pathways of differentiation of memory T cells. With these state of the art technologies the transcriptomics and genomics of Ag-specific T cells can be more definitively elucidated. PMID:26274954

  14. Hibernation is associated with depression of T-cell independent humoral immune responses in the 13-lined ground squirrel.

    PubMed

    Bouma, Hjalmar R; Henning, Robert H; Kroese, Frans G M; Carey, Hannah V

    2013-03-01

    Mammalian hibernation consists of periods of low metabolism and body temperature (torpor), interspersed by euthermic arousal periods. The function of both the innate and adaptive immune system is suppressed during hibernation. In this study, we analyzed the humoral adaptive immune response to a T-cell independent (TI-2) and a T-cell dependent (TD) antigen. Thirteen-lined ground squirrels were immunized in summer or during hibernation with either a TI-2 or TD antigen on day 0 and day 14. Blood was drawn on day 0, 7, 14, 21 and 28. Both types of antigens induced a significant rise in antibody titer in summer animals. Much to our surprise, however, only immunization with the TD antigen, and not with the TI-2 antigen induced a humoral response in hibernators. Flow cytometric analysis of CD4 (helper T-lymphocytes), CD8 (cytotoxic T-lymphocytes) and CD45RA (B-lymphocytes) in blood, spleen and lymph nodes ruled out massive apoptosis as explanation of the absent TI humoral response during hibernation. Rather, reduced TI-2 stimulation of B-lymphocytes, possibly due to lowered serum complement during torpor, may explain the reduced antibody production in response to a TI-2 antigen. These results demonstrate that hibernation diminishes the capacity to induce a TI-2 humoral immune response, while the capacity to induce a humoral response to a TD antigen is maintained.

  15. Continuum Model of T-cell Avidity: Understanding Autoreactive and Regulatory T-Cell Responses in Type 1 Diabetes

    PubMed Central

    Jaberi-Douraki, Majid; Pietropaolo, Massimo; Khadra, Anmar

    2015-01-01

    Type 1 diabetes (T1D) is an autoimmune disease that results from the destruction of insulin-secreting pancreatic β cells, leading to abolition of insulin secretion and onset of diabetes. Cytotoxic CD4+ and CD8+ T cells, activated by antigen presenting cells (APCs), are both implicated in disease onset and progression. Regulatory T cells (Tregs), on the other hand, play a leading role in regulating immunological tolerance and resistant homeostasis in T1D by supressing effector T cells (Teffs). Recent data indicates that after activation, conventional Teffs transiently produce interleukin IL-2, a cytokine that acts as a growth factor for both Teffs and Tregs. Tregs suppress Teffs through IL-2 deprivation, competition and Teff conversion into inducible Tregs (iTregs). To investigate the interactions of these components during T1D progression, a mathematical model of T-cell dynamics is developed as a predictor of β-cell loss, with the underlying hypothesis that avidity of Teffs and Tregs, i.e., the binding affinity of T-cell receptors to peptide-major histocompatibility complexes on host cells, is continuum. The model is used to infer a set of criteria that determines susceptibility to T1D in high risk (HR) subjects. Our findings show that diabetes onset is guided by the absence of Treg-to-Teff dominance at specific high avidities rather than over the whole range of avidity, and that the lack of overall dominance of Teffs-to-Tregs over time is the underlying cause of the “honeymoon period”, the remission phase observed in some T1D patients. The model also suggests that competition between Teffs and Tregs is more effective than Teff-induction into iTregs in suppressing Teffs, and that a prolonged full width at half maximum of IL-2 release is a necessary condition for curbing disease onset. Finally, the model provides a rationale for observing rapid and slow progressors of T1D based on modest heterogeneity in the kinetic parameters. PMID:26271890

  16. Lack of variant specific CD8+ T-cell response against mutant and pre-existing variants leads to outgrowth of particular clones in acute hepatitis C

    PubMed Central

    2013-01-01

    Background CTL escape mutations have been described during acute hepatitis C in patients who developed chronic disease later on. Our aim was to investigate the mutual relationship between HCV specific CD8+ T cells and evolution of the viral sequence during early acute HCV infection. Results We sequenced multiple clones of NS3 1406 epitope in 4 HLA-A*02 patients with acute hepatitis C genotype 1b infection. Pentamers specific for the variants were used to monitor the corresponding CD8+ T cell response. We observed outgrowth of mutations, which induced only a weak and thus potentially insufficient CD8+ T cell response. In one patient we observed outgrowth of variant epitopes with similarities to a different genotype rather than de novo mutations most probably due to a lack of responsiveness to these likely pre-existing variants. We could show that in acute hepatitis C CTL escape mutations occur much earlier than demonstrated in previous studies. Conclusions The adaption of the virus to a new host is characterized by a high and rapid variability in epitopes under CD8+ T cell immune pressure. This adaption takes place during the very early phase of acute infection and strikingly some sequences were reduced below the limit of detection at some time points but were detected at high frequency again at later time points. Independent of the observed variability, HCV-specific CD8+ T cell responses decline and no adaption to different or new antigens during the course of infection could be detected. PMID:24073713

  17. Synovial fluid antigen-presenting cells unmask peripheral blood T cell responses to bacterial antigens in inflammatory arthritis.

    PubMed Central

    Life, P F; Viner, N J; Bacon, P A; Gaston, J S

    1990-01-01

    We and others have previously shown that synovial fluid (SF) mononuclear cells (MC) from patients with both reactive arthritis and other inflammatory arthritides proliferate in vitro in response to bacteria clinically associated with the triggering of reactive arthritis. In all cases, such SFMC responses are greater than the corresponding peripheral blood (PB) MC responses, often markedly so, and the mechanism for this is unclear. We have investigated this phenomenon by comparing the relative abilities of irradiated non-T cells derived from PB and SF to support autologous T cell responses to ReA-associated bacteria. Seven patients whose SFMC had been shown previously to respond to bacteria were studied. We demonstrate antigen-specific responses of PB T cells to bacteria in the presence of SF non-T cells which are in marked contrast to the minimal responses of either unfractionated PBMC or PB T cells reconstituted with PB non-T cells. We also show that PB, but not SF T cells respond strongly to autologous SF non-T cells in the absence of antigen or mitogen. These findings demonstrate that SF antigen-presenting cells (APC) are potent activators of PB T cells. We conclude that the contrasting responses of SFMC and PBMC to bacterial antigens may be accounted for at least in part by an enhanced ability of SF APC to support T cell proliferative responses. PMID:2311298

  18. Impaired in vitro T-cell responses in patients with community acquired pneumonia.

    PubMed

    Bay, M L; Mahuad, R D; Urízar, L A; Morini, J C; Bottassol, O A

    1997-01-01

    To evaluate the status of the cellular immune response of patients with community acquired pneumonia (CAP), 8 CAP cases were studied for their in vitro T-cell responses to concanavalin A (Con A), tuberculin, and candidin, as well as levels of major T-cell populations in peripheral blood. Assessment on admission revealed that CAP patients had significantly decreased responses to both antigen and mitogen driven lymphocyte proliferation when compared to age and sex matched controls. Studies performed upon 1 week of antibiotic treatment made evident, in turn, that clinical improvement was accompanied by a reestablishment of the in vitro responses to tuberculin and candidin, whereas the lymphoproliferation induced by Con A remained decreased as in its first evaluation. Data from admission and day 7 of treatment showed no significant differences as to the levels of peripheral T-cell subsets when compared to those of healthy controls. Our results indicate that CAP coincides with reduced in vitro T-cell responses to antigen and mitogen stimulation.

  19. A Threshold Level of Intratumor CD8+ T-cell PD1 Expression Dictates Therapeutic Response to Anti-PD1.

    PubMed

    Ngiow, Shin Foong; Young, Arabella; Jacquelot, Nicolas; Yamazaki, Takahiro; Enot, David; Zitvogel, Laurence; Smyth, Mark J

    2015-09-15

    Despite successes, thus far, a significant proportion of the patients treated with anti-PD1 antibodies have failed to respond. We use mouse tumor models of anti-PD1 sensitivity and resistance and flow cytometry to assess tumor-infiltrating immune cells immediately after therapy. We demonstrate that the expression levels of T-cell PD1 (PD1(lo)), myeloid, and T-cell PDL1 (PDL1(hi)) in the tumor microenvironment inversely correlate and dictate the efficacy of anti-PD1 mAb and function of intratumor CD8(+) T cells. In sensitive tumors, we reveal a threshold for PD1 downregulation on tumor-infiltrating CD8(+) T cells below which the release of adaptive immune resistance is achieved. In contrast, PD1(hi) T cells in resistant tumors fail to be rescued by anti-PD1 therapy and remain dysfunctional unless intratumor PDL1(lo) immune cells are targeted. Intratumor Tregs are partly responsible for the development of anti-PD1-resistant tumors and PD1(hi) CD8(+) T cells. Our analyses provide a framework to interrogate intratumor CD8(+) T-cell PD1 and immune PDL1 levels and response in human cancer.

  20. Adaptive immune cells temper initial innate responses

    PubMed Central

    Kim, Kwang Dong; Zhao, Jie; Auh, Sogyong; Yang, Xuanming; Du, Peishuang; Tang, Hong; Fu, Yang-Xin

    2008-01-01

    Toll-like receptors (TLRs) recognize conserved microbial structures called pathogen-associated molecular patterns. Signaling from TLRs leads to upregulation of co-stimulatory molecules for better priming of T cells and secretion of inflammatory cytokines by innate immune cells1–4. Lymphocytedeficient hosts often die of acute infection, presumably owing to their lack of an adaptive immune response to effectively clear pathogens. However, we show here that an unleashed innate immune response due to the absence of residential T cells can also be a direct cause of death. Viral infection or administration of poly(I:C), a ligand for TLR3, led to cytokine storm in T-cell- or lymphocyte-deficient mice in a fashion dependent on NK cells and tumor necrosis factor. We have further shown, through the depletion of CD4+ and CD8+ cells in wild-type mice and the transfer of T lymphocytes into Rag-1–deficient mice, respectively, that T cells are both necessary and sufficient to temper the early innate response. In addition to the effects of natural regulatory T cells, close contact of resting CD4+CD25−Foxp3− or CD8+ T cells with innate cells could also suppress the cytokine surge by various innate cells in an antigen-independent fashion. Therefore, adaptive immune cells have an unexpected role in tempering initial innate responses. PMID:17891146

  1. Adaptive immune cells temper initial innate responses.

    PubMed

    Kim, Kwang Dong; Zhao, Jie; Auh, Sogyong; Yang, Xuanming; Du, Peishuang; Tang, Hong; Fu, Yang-Xin

    2007-10-01

    Toll-like receptors (TLRs) recognize conserved microbial structures called pathogen-associated molecular patterns. Signaling from TLRs leads to upregulation of co-stimulatory molecules for better priming of T cells and secretion of inflammatory cytokines by innate immune cells. Lymphocyte-deficient hosts often die of acute infection, presumably owing to their lack of an adaptive immune response to effectively clear pathogens. However, we show here that an unleashed innate immune response due to the absence of residential T cells can also be a direct cause of death. Viral infection or administration of poly(I:C), a ligand for TLR3, led to cytokine storm in T-cell- or lymphocyte-deficient mice in a fashion dependent on NK cells and tumor necrosis factor. We have further shown, through the depletion of CD4+ and CD8+ cells in wild-type mice and the transfer of T lymphocytes into Rag-1-deficient mice, respectively, that T cells are both necessary and sufficient to temper the early innate response. In addition to the effects of natural regulatory T cells, close contact of resting CD4+CD25-Foxp3- or CD8+ T cells with innate cells could also suppress the cytokine surge by various innate cells in an antigen-independent fashion. Therefore, adaptive immune cells have an unexpected role in tempering initial innate responses.

  2. CD4 T Cells Mediate Both Positive and Negative Regulation of the Immune Response to HIV Infection: Complex Role of T Follicular Helper Cells and Regulatory T Cells in Pathogenesis

    PubMed Central

    Phetsouphanh, Chansavath; Xu, Yin; Zaunders, John

    2015-01-01

    HIV-1 infection results in chronic activation of cells in lymphoid tissue, including T cells, B-cells, and myeloid lineage cells. The resulting characteristic hyperplasia is an amalgam of proliferating host immune cells in the adaptive response, increased concentrations of innate response mediators due to viral and bacterial products, and homeostatic responses to inflammation. While it is generally thought that CD4 T cells are greatly depleted, in fact, two types of CD4 T cells appear to be increased, namely, regulatory T cells (Tregs) and T follicular helper cells (Tfh). These cells have opposing roles, but may both be important in the pathogenic process. Whether Tregs are failing in their role to limit lymphocyte activation is unclear, but there is no doubt now that Tfh are associated with B-cell hyperplasia and increased germinal center activity. Antiretroviral therapy may reduce the lymphocyte activation, but not completely, and therefore, there is a need for interventions that selectively enhance normal CD4 function without exacerbating Tfh, B-cell, or Treg dysfunction. PMID:25610441

  3. Platelet-derived growth factor is a potent biologic response modifier of T cells

    PubMed Central

    1991-01-01

    Freshly isolated lymph node (LN) cells cultured in serum-containing medium were restricted to produce primarily interleukin 2 (IL-2) subsequent to T cell activation. Only minimal amounts of IL-4, IL-5, or interferon gamma (IFN-gamma) were produced under these conditions. Similar populations of LN cells cultured in serum-free medium were able to produce a variety of lymphokines after T cell activation, with the relative quantities of each species being dependent upon the lymphoid organ source of the lymphocytes. A similar relationship in the patterns of lymphokines produced by activated T cell hybridomas maintained under serum-free conditions was also observed, whereas activation in serum- supplemented media resulted in a predominant restriction to the secretion of IL-2. Additional studies determined that the entity in serum responsible for restricting T cell function in vitro was platelet- derived growth factor (PDGF). The PDGF-BB isoform was established to be the most active in the regulation of T cell function, enhancing IL-2 while depressing the production of IL-4, IL-5, and IFN-gamma at concentrations below 1 ng/ml. PDGF-AB was also found to be quite active, however, this isoform of PDGF was incapable of influencing IFN- gamma production at the concentrations tested. PDGF-AA was very weakly active. It therefore appears that PDGF, acting primarily through a beta receptor subunit (either alpha/beta- or beta/beta-type receptors) is able to influence profoundly the behavior of T cells, with some of its modulatory effects exhibiting isoform specificity. This is reflected by an enhancement in the production of IL-2, while simultaneously depressing the secretion of IL-4, IL-5, and IFN-gamma (PDGF-BB only) after T cell activation. Kinetic studies, where cell supernatants were analyzed both 24 and 48 h after T cell activation, suggested that "desensitization" to PDGF influences can occur naturally in vitro. Those species of lymphokines that were inhibited by PDGF over

  4. Re-adapting T cells for cancer therapy: from mouse models to clinical trials.

    PubMed

    Stromnes, Ingunn M; Schmitt, Thomas M; Chapuis, Aude G; Hingorani, Sunil R; Greenberg, Philip D

    2014-01-01

    Adoptive T-cell therapy involves the isolation, expansion, and reinfusion of T lymphocytes with a defined specificity and function as a means to eradicate cancer. Our research has focused on specifying the requirements for tumor eradication with antigen-specific T cells and T cells transduced to express a defined T-cell receptor (TCR) in mouse models and then translating these strategies to clinical trials. Our design of T-cell-based therapy for cancer has reflected efforts to identify the obstacles that limit sustained effector T-cell activity in mice and humans, design approaches to enhance T-cell persistence, develop methods to increase TCR affinity/T-cell functional avidity, and pursue strategies to overcome tolerance and immunosuppression. With the advent of genetic engineering, a highly functional population of T cells can now be rapidly generated and tailored for the targeted malignancy. Preclinical studies in faithful and informative mouse models, in concert with knowledge gained from analyses of successes and limitations in clinical trials, are shaping how we continue to develop, refine, and broaden the applicability of this approach for cancer therapy.

  5. A Numerically Subdominant CD8 T Cell Response to Matrix Protein of Respiratory Syncytial Virus Controls Infection with Limited Immunopathology

    PubMed Central

    Liu, Jie; Haddad, Elias K.; Marceau, Joshua; Morabito, Kaitlyn M.; Rao, Srinivas S.; Filali-Mouhim, Ali; Sekaly, Rafick-Pierre; Graham, Barney S.

    2016-01-01

    CD8 T cells are involved in pathogen clearance and infection-induced pathology in respiratory syncytial virus (RSV) infection. Studying bulk responses masks the contribution of individual CD8 T cell subsets to protective immunity and immunopathology. In particular, the roles of subdominant responses that are potentially beneficial to the host are rarely appreciated when the focus is on magnitude instead of quality of response. Here, by evaluating CD8 T cell responses in CB6F1 hybrid mice, in which multiple epitopes are recognized, we found that a numerically subdominant CD8 T cell response against DbM187 epitope of the virus matrix protein expressed high avidity TCR and enhanced signaling pathways associated with CD8 T cell effector functions. Each DbM187 T effector cell lysed more infected targets on a per cell basis than the numerically dominant KdM282 T cells, and controlled virus replication more efficiently with less pulmonary inflammation and illness than the previously well-characterized KdM282 T cell response. Our data suggest that the clinical outcome of viral infections is determined by the integrated functional properties of a variety of responding CD8 T cells, and that the highest magnitude response may not necessarily be the best in terms of benefit to the host. Understanding how to induce highly efficient and functional T cells would inform strategies for designing vaccines intended to provide T cell-mediated immunity. PMID:26943673

  6. Visualizing Chemokine-Dependent T Cell Activation and Migration in Response to Central Nervous System Infection

    PubMed Central

    Carson, Monica J.; Wilson, Emma H.

    2014-01-01

    In response to central nervous system (CNS) injury and infection, astrocytes, neurons, and CNS vasculature express several chemokines, including CCL21. Quantitative polymerase chain reaction (qPCR), western blot, and immunohistochemical methods can quantify mRNA and protein expression. However, these methods do not quantify chemokine bioavailability and bioactivity, variables modified by many environ mental factors including composition of extracellular matrix (ECM). Here we illustrate how two-photon microscopy and carboxyfluorescein succinimidyl ester (CFSE or CFDA SE) labeling of T cells coupled with flow cytometry can be used as tools to assess chemokine-mediated regulation of T cell proliferation, activation, and migration. PMID:23625499

  7. Characterization of Human CD8 T Cell Responses in Dengue Virus-Infected Patients from India

    PubMed Central

    Chandele, Anmol; Sewatanon, Jaturong; Gunisetty, Sivaram; Singla, Mohit; Onlamoon, Nattawat; Akondy, Rama S.; Kissick, Haydn Thomas; Nayak, Kaustuv; Reddy, Elluri Seetharami; Kalam, Haroon; Kumar, Dhiraj; Verma, Anil; Panda, HareKrushna; Wang, Siyu; Angkasekwinai, Nasikarn; Pattanapanyasat, Kovit; Chokephaibulkit, Kulkanya; Lodha, Rakesh; Kabra, Sushil; Ahmed, Rafi

    2016-01-01

    ABSTRACT Epidemiological studies suggest that India has the largest number of dengue virus infection cases worldwide. However, there is minimal information about the immunological responses in these patients. CD8 T cells are important in dengue, because they have been implicated in both protection and immunopathology. Here, we provide a detailed analysis of HLA-DR+ CD38+ and HLA-DR− CD38+ effector CD8 T cell subsets in dengue patients from India and Thailand. Both CD8 T cell subsets expanded and expressed markers indicative of antigen-driven proliferation, tissue homing, and cytotoxic effector functions, with the HLA-DR+ CD38+ subset being the most striking in these effector qualities. The breadth of the dengue-specific CD8 T cell response was diverse, with NS3-specific cells being the most dominant. Interestingly, only a small fraction of these activated effector CD8 T cells produced gamma interferon (IFN-γ) when stimulated with dengue virus peptide pools. Transcriptomics revealed downregulation of key molecules involved in T cell receptor (TCR) signaling. Consistent with this, the majority of these CD8 T cells remained IFN-γ unresponsive even after TCR-dependent polyclonal stimulation (anti-CD3 plus anti-CD28) but produced IFN-γ by TCR-independent polyclonal stimulation (phorbol 12-myristate 13-acetate [PMA] plus ionomycin). Thus, the vast majority of these proliferating, highly differentiated effector CD8 T cells probably acquire TCR refractoriness at the time the patient is experiencing febrile illness that leads to IFN-γ unresponsiveness. Our studies open novel avenues for understanding the mechanisms that fine-tune the balance between CD8 T cell-mediated protective versus pathological effects in dengue. IMPORTANCE Dengue is becoming a global public health concern. Although CD8 T cells have been implicated both in protection and in the cytokine-mediated immunopathology of dengue, how the balance is maintained between these opposing functions remains

  8. RIG-I Signaling Is Critical for Efficient Polyfunctional T Cell Responses during Influenza Virus Infection

    PubMed Central

    Kandasamy, Matheswaran; Suryawanshi, Amol; Tundup, Smanla; Perez, Jasmine T.; Schmolke, Mirco; Manicassamy, Santhakumar; Manicassamy, Balaji

    2016-01-01

    Retinoic acid inducible gene-I (RIG-I) is an innate RNA sensor that recognizes the influenza A virus (IAV) RNA genome and activates antiviral host responses. Here, we demonstrate that RIG-I signaling plays a crucial role in restricting IAV tropism and regulating host immune responses. Mice deficient in the RIG-I-MAVS pathway show defects in migratory dendritic cell (DC) activation, viral antigen presentation, and priming of CD8+ and CD4+ T cell responses during IAV infection. These defects result in decreased frequency of polyfunctional effector T cells and lowered protection against heterologous IAV challenge. In addition, our data show that RIG-I activation is essential for protecting epithelial cells and hematopoietic cells from IAV infection. These diverse effects of RIG-I signaling are likely imparted by the actions of type I interferon (IFN), as addition of exogenous type I IFN is sufficient to overcome the defects in antigen presentation by RIG-I deficient BMDC. Moreover, the in vivo T cell defects in RIG-I deficient mice can be overcome by the activation of MDA5 –MAVS via poly I:C treatment. Taken together, these findings demonstrate that RIG-I signaling through MAVS is critical for determining the quality of polyfunctional T cell responses against IAV and for providing protection against subsequent infection from heterologous or novel pandemic IAV strains. PMID:27438481

  9. RIG-I Signaling Is Critical for Efficient Polyfunctional T Cell Responses during Influenza Virus Infection.

    PubMed

    Kandasamy, Matheswaran; Suryawanshi, Amol; Tundup, Smanla; Perez, Jasmine T; Schmolke, Mirco; Manicassamy, Santhakumar; Manicassamy, Balaji

    2016-07-01

    Retinoic acid inducible gene-I (RIG-I) is an innate RNA sensor that recognizes the influenza A virus (IAV) RNA genome and activates antiviral host responses. Here, we demonstrate that RIG-I signaling plays a crucial role in restricting IAV tropism and regulating host immune responses. Mice deficient in the RIG-I-MAVS pathway show defects in migratory dendritic cell (DC) activation, viral antigen presentation, and priming of CD8+ and CD4+ T cell responses during IAV infection. These defects result in decreased frequency of polyfunctional effector T cells and lowered protection against heterologous IAV challenge. In addition, our data show that RIG-I activation is essential for protecting epithelial cells and hematopoietic cells from IAV infection. These diverse effects of RIG-I signaling are likely imparted by the actions of type I interferon (IFN), as addition of exogenous type I IFN is sufficient to overcome the defects in antigen presentation by RIG-I deficient BMDC. Moreover, the in vivo T cell defects in RIG-I deficient mice can be overcome by the activation of MDA5 -MAVS via poly I:C treatment. Taken together, these findings demonstrate that RIG-I signaling through MAVS is critical for determining the quality of polyfunctional T cell responses against IAV and for providing protection against subsequent infection from heterologous or novel pandemic IAV strains.

  10. Polyfunctional CD4 T cells in the response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB and HIV. However, the assessment of this response in bovine infections was not fe...

  11. T cell responses in hepatitis C virus infection: historical overview and goals for future research.

    PubMed

    Holz, Lauren; Rehermann, Barbara

    2015-02-01

    Hepatitis C virus (HCV)-specific T cells are key factors in the outcome of acute HCV infection and in protective immunity. This review recapitulates the steps that immunologists have taken in the past 25years to dissect the role of T cell responses in HCV infection. It describes technical as well as disease-specific challenges that were caused by the inapparent onset of acute HCV infection, the difficulty to identify subjects who spontaneously clear HCV infection, the low frequency of HCV-specific T cells in the blood of chronically infected patients, and the lack of small animal models with intact immune systems to study virus-host interaction. The review provides a historical perspective on techniques and key findings, and identifies areas for future research.

  12. Armc5 deletion causes developmental defects and compromises T-cell immune responses

    PubMed Central

    Hu, Yan; Lao, Linjiang; Mao, Jianning; Jin, Wei; Luo, Hongyu; Charpentier, Tania; Qi, Shijie; Peng, Junzheng; Hu, Bing; Marcinkiewicz, Mieczyslaw Martin; Lamarre, Alain; Wu, Jiangping

    2017-01-01

    Armadillo repeat containing 5 (ARMC5) is a cytosolic protein with no enzymatic activities. Little is known about its function and mechanisms of action, except that gene mutations are associated with risks of primary macronodular adrenal gland hyperplasia. Here we map Armc5 expression by in situ hybridization, and generate Armc5 knockout mice, which are small in body size. Armc5 knockout mice have compromised T-cell proliferation and differentiation into Th1 and Th17 cells, increased T-cell apoptosis, reduced severity of experimental autoimmune encephalitis, and defective immune responses to lymphocytic choriomeningitis virus infection. These mice also develop adrenal gland hyperplasia in old age. Yeast 2-hybrid assays identify 16 ARMC5-binding partners. Together these data indicate that ARMC5 is crucial in fetal development, T-cell function and adrenal gland growth homeostasis, and that the functions of ARMC5 probably depend on interaction with multiple signalling pathways. PMID:28169274

  13. CD8+ T-Cell Responses in Hepatitis B and C: The (HLA-) A, B, and C of Hepatitis B and C.

    PubMed

    Nitschke, Katja; Luxenburger, Hendrik; Kiraithe, Muthamia M; Thimme, Robert; Neumann-Haefelin, Christoph

    Approximately 500 million people are chronically infected with the hepatitis B virus (HBV) or hepatitis C virus (HCV) worldwide and are thus at high risk of progressive liver disease, leading to liver fibrosis, cirrhosis and ultimately hepatocellular cancer. Virus-specific CD8+ T-cells play a major role in viral clearance in >90% of adult patients who clear HBV and in approximately 30% of patients who clear HCV in acute infection. However, several mechanisms contribute to the failure of the adaptive CD8+ T-cell response in those patients who progress to chronic infection. These include viral mutations leading to escape from the CD8+ T-cell response as well as exhaustion and dysfunction of virus-specific CD8+ T-cells. Antiviral efficacy of the virus-specific CD8+ T-cell response also strongly depends on its restriction by specific human leukocyte antigens (HLA) class I alleles. Our review will summarize the role of HLA-A, B and C-restricted CD8+ T-cells in HBV and HCV infection. Due to the current lack of a comprehensive database of HBV- and HCV-specific CD8+ T-cell epitopes, we also provide a summary of the repertoire of currently well-described HBV- and HCV-specific CD8+ T-cell epitopes. A better understanding of the factors that contribute to the success or failure of virus-specific CD8+ T-cells may help to develop new therapeutic options for HBV eradication in patients with chronic HBV infection (therapeutic vaccination and/or immunomodulation) as well as a prophylactic vaccine against HCV infection.

  14. Fetal-specific CD8+ cytotoxic T cell responses develop during normal human pregnancy and exhibit broad functional capacity.

    PubMed

    Lissauer, David; Piper, Karen; Goodyear, Oliver; Kilby, Mark D; Moss, Paul A H

    2012-07-15

    Tolerance of the semiallogeneic fetus presents a significant challenge to the maternal immune system during human pregnancy. T cells with specificity for fetal epitopes have been detected in women with a history of previous pregnancy, but it has been thought that such fetal-specific cells were generally deleted during pregnancy as a mechanism to maintain maternal tolerance of the fetus. We used MHC-peptide dextramer multimers containing an immunodominant peptide derived from HY to identify fetal-specific T cells in women who were pregnant with a male fetus. Fetal-specific CD8(+) T lymphocytes were observed in half of all pregnancies and often became detectable from the first trimester. The fetal-specific immune response increased during pregnancy and persisted in the postnatal period. Fetal-specific cells demonstrated an effector memory phenotype and were broadly functional. They retained their ability to proliferate, secrete IFN-γ, and lyse target cells following recognition of naturally processed peptide on male cells. These data show that the development of a fetal-specific adaptive cellular immune response is a normal consequence of human pregnancy and that unlike reports from some murine models, fetal-specific T cells are not deleted during human pregnancy. This has broad implications for study of the natural physiology of pregnancy and for the understanding of pregnancy-related complications.

  15. Pathogen-Induced Proapoptotic Phenotype and High CD95 (Fas) Expression Accompany a Suboptimal CD8+ T-Cell Response: Reversal by Adenoviral Vaccine

    PubMed Central

    Vasconcelos, José Ronnie; Bruña–Romero, Oscar; Araújo, Adriano F.; Dominguez, Mariana R.; Ersching, Jonatan; de Alencar, Bruna C. G.; Machado, Alexandre V.; Gazzinelli, Ricardo T.; Bortoluci, Karina R.; Amarante-Mendes, Gustavo P.; Lopes, Marcela F.; Rodrigues, Mauricio M.

    2012-01-01

    MHC class Ia-restricted CD8+ T cells are important mediators of the adaptive immune response against infections caused by intracellular microorganisms. Whereas antigen-specific effector CD8+ T cells can clear infection caused by intracellular pathogens, in some circumstances, the immune response is suboptimal and the microorganisms survive, causing host death or chronic infection. Here, we explored the cellular and molecular mechanisms that could explain why CD8+ T cell-mediated immunity during infection with the human protozoan parasite Trypanosoma cruzi is not optimal. For that purpose, we compared the CD8+ T-cell mediated immune responses in mice infected with T. cruzi or vaccinated with a recombinant adenovirus expressing an immunodominant parasite antigen. Several functional and phenotypic characteristics of specific CD8+ T cells overlapped. Among few exceptions was an accelerated expansion of the immune response in adenoviral vaccinated mice when compared to infected ones. Also, there was an upregulated expression of the apoptotic-signaling receptor CD95 on the surface of specific T cells from infected mice, which was not observed in the case of adenoviral-vaccinated mice. Most importantly, adenoviral vaccine provided at the time of infection significantly reduced the upregulation of CD95 expression and the proapoptotic phenotype of pathogen-specific CD8+ cells expanded during infection. In parallel, infected adenovirus-vaccinated mice had a stronger CD8 T-cell mediated immune response and survived an otherwise lethal infection. We concluded that a suboptimal CD8+ T-cell response is associated with an upregulation of CD95 expression and a proapoptotic phenotype. Both can be blocked by adenoviral vaccination. PMID:22615561

  16. Clonal expansion of antitumor T cells in breast cancer correlates with response to neoadjuvant chemotherapy

    PubMed Central

    Park, Jae-Hyun; Jang, Miran; Tarhan, Yunus Emre; Katagiri, Toyomasa; Sasa, Mitsunori; Miyoshi, Yasuo; Kalari, Krishna R.; Suman, Vera J.; Weinshilboum, Richard; Wang, Liewei; Boughey, Judy C.; Goetz, Matthew P.; Nakamura, Yusuke

    2016-01-01

    The immune microenvironment of tumor plays a critical role in therapeutic responses to chemotherapy. Cancer tissues are composed of a complex network between anti-tumor and pro-tumor immune cells and molecules; therefore a comprehensive analysis of the tumor immune condition is imperative for better understanding of the roles of the immune microenvironment in anticancer treatment response. In this study, we performed T cell receptor (TCR) repertoire analysis of tumor infiltrating T cells (TILs) in cancer tissues of pre- and post-neoadjuvant chemotherapy (NAC) from 19 breast cancer patients; five cases showed CR (complete response), ten showed PR (partial response), and four showed SD/PD (stable disease/progressive disease) to the treatment. From the TCR sequencing results, we calculated the diversity index of the TCRβ chain and found that clonal expansion of TILs could be detected in patients who showed CR or PR to NAC. Noteworthy, the diversity of TCR was further reduced in the post-NAC tumors of CR patients. Our quantitative RT-PCR also showed that expression ratio of CD8/Foxp3 was significantly elevated in the post-NAC tumors of CR cases (p=0.0032), indicating that antitumor T cells were activated and enriched in these tumors. Collectively, our findings suggest that the clonal expansion of antitumor T cells may be a critical factor associated with response to chemotherapy and that their TCR sequences might be applicable for the development of TCR-engineered T cells treatment for individual breast cancer patients when their tumors relapse. PMID:27278091

  17. Effects of aging on human leukocytes (part II): immunophenotyping of adaptive immune B and T cell subsets.

    PubMed

    Stervbo, Ulrik; Bozzetti, Cecilia; Baron, Udo; Jürchott, Karsten; Meier, Sarah; Mälzer, Julia Nora; Nienen, Mikalai; Olek, Sven; Rachwalik, Dominika; Schulz, Axel Ronald; Neumann, Avidan; Babel, Nina; Grützkau, Andreas; Thiel, Andreas

    2015-10-01

    Immunosenescence results from a continuous deterioration of immune responses resulting in a decreased response to vaccines. A well-described age-related alteration of the immune system is the decrease of de novo generation of T and B cells. In addition, the accumulation of memory cells and loss of diversity in antigen specificities resulting from a lifetime of exposure to pathogens has also been described. However, the effect of aging on subsets of γδTCR(+) T cells and Tregs has been poorly described, and the efficacy of the recall response to common persistent infections in the elderly remains obscure. Here, we investigated alterations in the subpopulations of the B and T cells among 24 healthy young (aged 19-30) and 26 healthy elderly (aged 53-67) individuals. The analysis was performed by flow cytometry using freshly collected peripheral blood. γδTCR(+) T cells were overall decreased, while CD4(+)CD8(-) cells among γδTCR(+) T cells were increased in the elderly. Helios(+)Foxp3(+) and Helios(-)Foxp3(+) Treg cells were unaffected with age. Recent thymic emigrants, based on CD31 expression, were decreased among the Helios(+)Foxp3(+), but not the Helios(-)Foxp3(+) cell populations. We observed a decrease in Adenovirus-specific CD4(+) and CD8(+) T cells and an increase in CMV-specific CD4(+) T cells in the elderly. Similarly, INFγ(+)TNFα(+) double-positive cells were decreased among activated T cells after Adenovirus stimulation but increased after CMV stimulation. The data presented here indicate that γδTCR(+) T cells might stabilize B cells, and functional senescence might dominate at higher ages than those studied here.

  18. Synthetic peptides containing B- and T-cell epitope of dengue virus-2 E domain III provoked B- and T-cell responses.

    PubMed

    Li, Shanfeng; Peng, Liang; Zhao, Wei; Zhong, Hua; Zhang, Fuchun; Yan, Ziqiang; Cao, Hong

    2011-05-09

    Our previous work applied a combination of bioinformatics approaches and in vitro assays to identify the dengue-2 virus (DENV-2)-specific B- and T-cell epitopes. In this report, we first evaluated the antigenicity of both B- and T-cell epitopes reacting with different sera against DENV-2 by ELISA as well as the ability of T-cell epitope to activate CD4(+) T-cell producing IFN-γ using ELISPOT, which showed a specific reactivity between either B- or T-cell epitope and DENV-2 antisera, and a significant increase of IFN-γ producing cells in DENV-2 infected mice. Then, a multi-epitope peptide containing the above B-, T-cell epitopes of envelope domain III (EDIII) of DENV-2 and pan-DR epitope (PADRE) was bioinformatically designed and synthesized. The verification of its immunogenicity and protective effect was performed in in vitro and in vivo experiments. The results showed that a high level of antibody in mice elicited by the multi-epitope peptide was detected by ELISA and the anti-peptide sera binding to the vero cells infected with DEN-2 was observed with immunofluorescence test. More importantly, the peptide could induce lymphoproliferation in vitro and a predominant Th1 type of immune response was examined by flow cytometry. We also found that the virus replication in the mice vaccinated with the multi-epitope peptide was obviously less than that of the control groups. These results may provide some important information for the development of dengue vaccine.

  19. Development and dynamics of robust T-cell responses to CML under imatinib treatment.

    PubMed

    Chen, Christiane I-U; Maecker, Holden T; Lee, Peter P

    2008-06-01

    Novel molecular targeted therapies, such as imatinib for chronic myelogenous leukemia (CML), represent the first agents that inhibit cancer cells more than other dividing cells, such as immune cells. We hypothesize that imatinib may create a window in which the immune response is partially restored while apoptotic leukemic cells are present, thus rendering leukemic cells immunogenic as patients enter remission. To detect and quantify antileukemia immune responses in an antigen-unbiased way, we used cryopreserved autologous pretreatment blood samples (representing predominantly leukemic cells) as stimulators to detect antileukemia T-cell responses in CML patients in remission on imatinib. We studied patients over time to address the dynamics of such responses. Our data show that antileukemia T-cell responses develop in the majority of CML patients (9 of 14) in remission and that CD4(+) T cells producing tumor necrosis factor-alpha (median 17.6%) represent the major response over interferon-gamma. This confirms the immune system's ability to respond to leukemia under certain conditions. Such responses may be further amplified as a potential therapy that synergizes with imatinib for improved control of CML.

  20. Full-Breadth Analysis of CD8+ T-Cell Responses in Acute Hepatitis C Virus Infection and Early Therapy

    PubMed Central

    Lauer, Georg M.; Lucas, Michaela; Timm, Joerg; Ouchi, Kei; Kim, Arthur Y.; Day, Cheryl L.; zur Wiesch, Julian Schulze; Paranhos-Baccala, Glaucia; Sheridan, Isabelle; Casson, Deborah R.; Reiser, Markus; Gandhi, Rajesh T.; Li, Bin; Allen, Todd M.; Chung, Raymond T.; Klenerman, Paul; Walker, Bruce D.

    2005-01-01

    Multispecific CD8+ T-cell responses are thought to be important for the control of acute hepatitis C virus (HCV) infection, but to date little information is actually available on the breadth of responses at early time points. Additionally, the influence of early therapy on these responses and their relationships to outcome are controversial. To investigate this issue, we performed comprehensive analysis of the breadth and frequencies of virus-specific CD8+ T-cell responses on the single epitope level in eight acutely infected individuals who were all started on early therapy. During the acute phase, responses against up to five peptides were identified. During therapy, CD8+ T-cell responses decreased rather than increased as virus was controlled, and no new specificities emerged. A sustained virological response following completion of treatment was independent of CD8+ T-cell responses, as well as CD4+ T-cell responses. Rapid recrudescence also occurred despite broad CD8+ T-cell responses. Importantly, in vivo suppression of CD3+ T cells using OKT3 in one subject did not result in recurrence of viremia. These data suggest that broad CD8+ T-cell responses alone may be insufficient to contain HCV replication, and also that early therapy is effective independent of such responses. PMID:16189000

  1. Immunization with vaccinia virus induces polyfunctional and phenotypically distinctive CD8+ T cell responses

    PubMed Central

    Precopio, Melissa L.; Betts, Michael R.; Parrino, Janie; Price, David A.; Gostick, Emma; Ambrozak, David R.; Asher, Tedi E.; Douek, Daniel C.; Harari, Alexandre; Pantaleo, Giuseppe; Bailer, Robert; Graham, Barney S.; Roederer, Mario; Koup, Richard A.

    2007-01-01

    Vaccinia virus immunization provides lifelong protection against smallpox, but the mechanisms of this exquisite protection are unknown. We used polychromatic flow cytometry to characterize the functional and phenotypic profile of CD8+ T cells induced by vaccinia virus immunization in a comparative vaccine trial of modified vaccinia virus Ankara (MVA) versus Dryvax immunization in which protection was assessed against subsequent Dryvax challenge. Vaccinia virus–specific CD8+ T cells induced by both MVA and Dryvax were highly polyfunctional; they degranulated and produced interferon γ, interleukin 2, macrophage inflammatory protein 1β, and tumor necrosis factor α after antigenic stimulation. Responding CD8+ T cells exhibited an unusual phenotype (CD45RO−CD27intermediate). The unique phenotype and high degree of polyfunctionality induced by vaccinia virus also extended to inserted HIV gene products of recombinant NYVAC. This quality of the CD8+ T cell response may be at least partially responsible for the profound efficacy of these vaccines in protection against smallpox and serves as a benchmark against which other vaccines can be evaluated. PMID:17535971

  2. Salmonella enterica serovar Typhi impairs CD4 T cell responses by reducing antigen availability.

    PubMed

    Atif, Shaikh M; Winter, Sebastian E; Winter, Maria G; McSorley, Stephen J; Bäumler, Andreas J

    2014-06-01

    Salmonella enterica serovar Typhi is associated with a disseminated febrile illness in humans, termed typhoid fever, while Salmonella enterica serovar Typhimurium causes localized gastroenteritis in immunocompetent individuals. One of the genetic differences between both pathogens is the presence in S. Typhi of TviA, a regulatory protein that shuts down flagellin (FliC) expression when bacteria transit from the intestinal lumen into the intestinal mucosa. Here we investigated the consequences of TviA-mediated flagellum gene regulation on flagellin-specific CD4 T cell responses in a mouse model of S. Typhimurium infection. Introduction of the S. Typhi tviA gene into S. Typhimurium suppressed antigen presentation of dendritic cells to flagellin-specific CD4 T cells in vitro. Furthermore, TviA-mediated repression of flagellin expression impaired the activation and proliferation of naive flagellin-specific CD4 T cells in Peyer's patches and mesenteric lymph nodes, which was accompanied by increased bacterial dissemination to the spleen. We conclude that TviA-mediated repression of flagellin expression reduces antigen availability, thereby weakening flagellin-specific CD4 T cell responses.

  3. Inhibition of allogeneic T-cell response by Kupffer cells expressing indoleamine 2,3-dioxygenase

    PubMed Central

    Yan, Mao-Lin; Wang, Yao-Dong; Tian, Yi-Feng; Lai, Zhi-De; Yan, Lv-Nan

    2010-01-01

    AIM: To explore the possibility and mechanism of inhibiting allogeneic T-cell responses by Kupffer cells (KC) pretreated with interferon-γ (IFN-γ) in vitro. METHODS: The expressions of indoleamine 2,3-dioxygenase (IDO) mRNA and FasL mRNA in KC pretreated with IFN-γ were studied with real-time polymerase chain reaction (PCR). The catabolism of tryptophan by IDO from KC was analyzed by high performance liquid chromatography. Allogeneic T-cell response was used to confirm the inhibition of KC in vitro. The proliferation of lymphocytes was detected using [3H] thymidine incorporation. Cell cycle and lymphocyte apoptosis were evaluated by flow cytometric assay. RESULTS: Real-time PCR revealed IDO mRNA and FasL mRNA expressions in KC pretreated with IFN-γ, and IDO catabolic effect was confirmed by a decrease in tryptophan and increase in kynurenine concentration. KC expressing IDO and FasL in BABL/c mice acquired the ability to suppress the proliferation of T-cells from C57BL/6, which could be blocked by addition of 1-methyl-tryptophan and anti-FasL antibody. KC expressing IDO could induce allogeneic T-cell apoptosis. CONCLUSION: In addition to Fas/FasL pathway, IDO may be another mechanism for KC to induce immune tolerance. PMID:20128035

  4. Only a Subset of Phosphoantigen-responsive γ9δ2 T cells Mediate Protective TB Immunity1

    PubMed Central

    Spencer, Charles Thomas; Abate, Getahun; Blazevic, Azra; Hoft, Daniel F.

    2009-01-01

    Mycobacterium tuberculosis and M. bovis-BCG induce potent expansions of human memory Vγ9+Vδ2+ T cells capable of IFN-γ production, cytolytic activity and mycobacterial growth inhibition. Certain phosphoantigens expressed by mycobacteria can stimulate γ9δ2 T cell expansions, suggesting that purified or synthetic forms of these phosphoantigens may be useful alone or as components of new vaccines or immunotherapeutics. However, we show that while mycobacteria-activated γ9δ2 T cells potently inhibit intracellular mycobacterial growth, phosphoantigen-activated γ9δ2 T cells fail to inhibit mycobacteria, although both develop similar effector cytokine and cytolytic functional capacities. γ9δ2 T cells receiving TLR-mediated co-stimulation during phosphoantigen activation also failed to inhibit mycobacterial growth. We hypothesized that mycobacteria express antigens, other than the previously identified phosphoantigens, that induce protective subsets of γ9δ2 T cells. Testing this hypothesis, we compared the TCR sequence diversity of γ9δ2 T cells expanded with BCG-infected versus phosphoantigen-treated DC. BCG-stimulated γ9δ2 T cells displayed a more restricted TCR diversity than phosphoantigen-activated γ9δ2 T cells. In addition, only a subset of phosphoantigen-activated γ9δ2 T cells functionally responded to mycobacteria-infected DC. Furthermore, differential inhibitory functions of BCG- and phosphoantigen-activated γ9δ2 T cells were confirmed at the clonal level and were not due to differences in TCR avidity. Our results demonstrate that BCG infection can activate and expand protective subsets of phosphoantigen responsive γ9δ2 T cells, and provide the first indication that γ9δ2 T cells can develop pathogen specificity similar to αβ T cells. Specific targeting of protective γ9δ2 T cell subsets will be important for future tuberculosis vaccines. PMID:18802050

  5. T cell activation.

    PubMed

    Smith-Garvin, Jennifer E; Koretzky, Gary A; Jordan, Martha S

    2009-01-01

    This year marks the 25th anniversary of the first Annual Review of Immunology article to describe features of the T cell antigen receptor (TCR). In celebration of this anniversary, we begin with a brief introduction outlining the chronology of the earliest studies that established the basic paradigm for how the engaged TCR transduces its signals. This review continues with a description of the current state of our understanding of TCR signaling, as well as a summary of recent findings examining other key aspects of T cell activation, including cross talk between the TCR and integrins, the role of costimulatory molecules, and how signals may negatively regulate T cell function.Acronyms and DefinitionsAdapter protein: cellular protein that functions to bridge molecular interactions via characteristic domains able to mediate protein/protein or protein/lipid interactions Costimulation: signals delivered to T cells by cell surface receptors other than the TCR itself that potentiate T cell activation cSMAC: central supramolecular activation cluster Immunoreceptor tyrosine-based activation motif (ITAM): a short peptide sequence in the cytoplasmic tails of key surface receptors on hematopoietic cells that is characterized by tyrosine residues that are phosphorylated by Src family PTKs, enabling the ITAM to recruit activated Syk family kinases Inside-out signaling: signals initiated by engagement of immunoreceptors that lead to conformational changes and clustering of integrins, thereby increasing the affinity and avidity of the integrins for their ligands NFAT: nuclear factor of activated T cells PI3K: phosphoinositide 3-kinase PKC: protein kinase C PLC: phospholipase C pMHC: peptide major histocompatibility complex (MHC) complex pSMAC: peripheral supramolecular activation cluster PTK: protein tyrosine kinase Signal transduction: biochemical events linking surface receptor engagement to cellular responses TCR: T cell antigen receptor

  6. Fragmentation of SIV-gag Vaccine Induces Broader T Cell Responses

    PubMed Central

    Benlahrech, Adel; Meiser, Andrea; Herath, Shanthi; Papagatsias, Timos; Athanasopoulos, Takis; Li, Fucheng; Self, Steve; Bachy, Veronique; Hervouet, Catherine; Logan, Karen; Klavinskis, Linda; Dickson, George; Patterson, Steven

    2012-01-01

    Background High mutation rates of human immunodeficiency virus (HIV) allows escape from T cell recognition preventing development of effective T cell vaccines. Vaccines that induce diverse T cell immune responses would help overcome this problem. Using SIV gag as a model vaccine, we investigated two approaches to increase the breadth of the CD8 T cell response. Namely, fusion of vaccine genes to ubiquitin to target the proteasome and increase levels of MHC class I peptide complexes and gene fragmentation to overcome competition between epitopes for presentation and recognition. Methodology/Principal Findings Three vaccines were compared: full-length unmodified SIV-mac239 gag, full-length gag fused at the N-terminus to ubiquitin and 7 gag fragments of equal size spanning the whole of gag with ubiquitin-fused to the N-terminus of each fragment. Genes were cloned into a replication defective adenovirus vector and immunogenicity assessed in an in vitro human priming system. The breadth of the CD8 T cell response, defined by the number of distinct epitopes, was assessed by IFN-γ-ELISPOT and memory phenotype and cytokine production evaluated by flow cytometry. We observed an increase of two- to six-fold in the number of epitopes recognised in the ubiquitin-fused fragments compared to the ubiquitin-fused full-length gag. In contrast, although proteasomal targeting was achieved, there was a marked reduction in the number of epitopes recognised in the ubiquitin-fused full-length gag compared to the full-length unmodified gene, but there were no differences in the number of epitope responses induced by non-ubiquitinated full-length gag and the ubiquitin-fused mini genes. Fragmentation and ubiquitination did not affect T cell memory differentiation and polyfunctionality, though most responses were directed against the Ad5 vector. Conclusion/Significance Fragmentation but not fusion with ubiquitin increases the breadth of the CD8 T vaccine response against SIV-mac239 gag

  7. Cross-reactive memory CD4+ T cells alter the CD8+ T-cell response to heterologous secondary dengue virus infections in mice in a sequence-specific manner.

    PubMed

    Beaumier, Coreen M; Rothman, Alan L

    2009-06-01

    Secondary dengue virus (DENV) infection is a major factor contributing to the risk for severe disease, an effect that depends upon the sequence of infection with different DENV serotypes. We previously reported sequence-dependent effects of secondary DENV infection on CD8+ T-cell responses in mice. To further evaluate the effect of infection sequence, we analyzed DENV-specific CD4+ T-cell responses and their relationship to the CD8+ T-cell response. Serotype cross-reactivity of CD4+ T-cell responses also depended upon the sequence of serotypes in this model. Furthermore, adoptive transfer of memory CD4+ T cells altered the response of memory CD8+ T cells to secondary infection. These data demonstrate the interaction of different components of the T-cell response in determining the immunological outcome of secondary DENV infection.

  8. Different Bla-g T cell antigens dominate responses in asthma versus rhinitis subjects

    PubMed Central

    Dillon, Myles B.C.; Schulten, Veronique; Oseroff, Carla; Paul, Sinu; Dullanty, Laura M.; Frazier, April; Belles, Xavier; Piulachs, Maria-Dolors; Visness, Cynthia; Bacharier, Leonard; Bloomberg, Gordon R.; Busse, Paula; Sidney, John; Peters, Bjoern; Sette, Alessandro

    2015-01-01

    Background and Objective The allergenicity of several German cockroach (Bla-g) antigens at the level of IgE responses is well established. However less is known about the specificity of CD4+ TH responses, and whether differences exist in associated magnitude or cytokine profiles as a function of disease severity. Methods Proteomic and transcriptomic techniques have been employed to identify novel antigens recognized by allergen-specific T cells. To characterize different TH functionalities of allergen-specific T cells, ELISPOT assays with sets of overlapping peptides covering the sequences of known allergens and novel antigens were employed to measure release of IL-5, IFNγ, IL-10, IL-17, and IL-21. Results Using these techniques, we characterized TH responses in a cohort of adult Bla-g sensitized subjects, either with (n=55) or without (n=17) asthma, and non-sensitized controls (n=20). T cell responses were detected for ten known Bla-g allergens and an additional ten novel Bla-g antigens; representing in total a 5-fold increase in the number of antigens demonstrated to be targeted by allergen-specific T cells. Responses of sensitized individuals regardless of asthma status were predominantly TH2, but higher in patients with diagnosed asthma. In asthmatic subjects Bla-g 5, 9 and 11 were immunodominant while, in contrast, non-asthmatic sensitized subjects responded mostly to Bla-g 5, 4, and the novel antigen NBGA5. Conclusions Asthmatic and non-asthmatic cockroach sensitized individuals exhibit similar TH2 polarized responses. Compared to non-asthmatics, however, asthmatic individuals have responses of higher magnitude and different allergen specificity. PMID:26414909

  9. Initial viral load determines the magnitude of the human CD8 T cell response to yellow fever vaccination.

    PubMed

    Akondy, Rama S; Johnson, Philip L F; Nakaya, Helder I; Edupuganti, Srilatha; Mulligan, Mark J; Lawson, Benton; Miller, Joseph D; Pulendran, Bali; Antia, Rustom; Ahmed, Rafi

    2015-03-10

    CD8 T cells are a potent tool for eliminating intracellular pathogens and tumor cells. Thus, eliciting robust CD8 T-cell immunity is the basis for many vaccines under development. However, the relationship between antigen load and the magnitude of the CD8 T-cell response is not well-described in a human immune response. Here we address this issue by quantifying viral load and the CD8 T-cell response in a cohort of 80 individuals immunized with the live attenuated yellow fever vaccine (YFV-17D) by sampling peripheral blood at days 0, 1, 2, 3, 5, 7, 9, 11, 14, 30, and 90. When the virus load was below a threshold (peak virus load < 225 genomes per mL, or integrated virus load < 400 genome days per mL), the magnitude of the CD8 T-cell response correlated strongly with the virus load (R(2) ∼ 0.63). As the virus load increased above this threshold, the magnitude of the CD8 T-cell responses saturated. Recent advances in CD8 T-cell-based vaccines have focused on replication-incompetent or single-cycle vectors. However, these approaches deliver relatively limited amounts of antigen after immunization. Our results highlight the requirement that T-cell-based vaccines should deliver sufficient antigen during the initial period of the immune response to elicit a large number of CD8 T cells that may be needed for protection.

  10. Polyfunctional cytokine responses by central memory CD4+T cells in response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CD4 T cells are crucial in immunity to tuberculosis (TB). Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB and HIV. Mycobacterium ...

  11. Polyfunctional cytokine responses by central memory CD4*T cells in response to bovine tuberculosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CD4 T cells are crucial in immunity to tuberculosis (TB). Polyfunctional CD4 T cells simultaneously produce interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and tumor necrosis factor-alpha (TNF-alpha) and play relevant roles in several chronic infections, including human TB. Mycobacterium bovis in...

  12. Adjuvant-enhanced CD4 T Cell Responses are Critical to Durable Vaccine Immunity

    PubMed Central

    Martins, Karen A.O.; Cooper, Christopher L.; Stronsky, Sabrina M.; Norris, Sarah L.W.; Kwilas, Steven A.; Steffens, Jesse T.; Benko, Jacqueline G.; van Tongeren, Sean A.; Bavari, Sina

    2015-01-01

    Protein-based vaccines offer a safer alternative to live-attenuated or inactivated vaccines but have limited immunogenicity. The identification of adjuvants that augment immunogenicity, specifically in a manner that is durable and antigen-specific, is therefore critical for advanced development. In this study, we use the filovirus virus-like particle (VLP) as a model protein-based vaccine in order to evaluate the impact of four candidate vaccine adjuvants on enhancing long term protection from Ebola virus challenge. Adjuvants tested include poly-ICLC (Hiltonol), MPLA, CpG 2395, and alhydrogel. We compared and contrasted antibody responses, neutralizing antibody responses, effector T cell responses, and T follicular helper (Tfh) cell frequencies with each adjuvant's impact on durable protection. We demonstrate that in this system, the most effective adjuvant elicits a Th1-skewed antibody response and strong CD4 T cell responses, including an increase in Tfh frequency. Using immune-deficient animals and adoptive transfer of serum and cells from vaccinated animals into naïve animals, we further demonstrate that serum and CD4 T cells play a critical role in conferring protection within effective vaccination regimens. These studies inform on the requirements of long term immune protection, which can potentially be used to guide screening of clinical-grade adjuvants for vaccine clinical development. PMID:26870818

  13. Polyfunctional responses by human T cells result from sequential release of cytokines

    PubMed Central

    Han, Qing; Bagheri, Neda; Bradshaw, Elizabeth M.; Hafler, David A.; Lauffenburger, Douglas A.; Love, J. Christopher

    2012-01-01

    The release of cytokines by T cells defines a significant part of their functional activity in vivo, and their ability to produce multiple cytokines has been associated with beneficial immune responses. To date, time-integrated end-point measurements have obscured whether these polyfunctional states arise from the simultaneous or successive release of cytokines. Here, we used serial, time-dependent, single-cell analysis of primary human T cells to resolve the temporal dynamics of cytokine secretion from individual cells after activation ex vivo. We show that multifunctional, Th1-skewed cytokine responses (IFN-γ, IL-2, TNFα) are initiated asynchronously, but the ensuing dynamic trajectories of these responses evolve programmatically in a sequential manner. That is, cells predominantly release one of these cytokines at a time rather than maintain active secretion of multiple cytokines simultaneously. Furthermore, these dynamic trajectories are strongly associated with the various states of cell differentiation suggesting that transient programmatic activities of many individual T cells contribute to sustained, population-level responses. The trajectories of responses by single cells may also provide unique, time-dependent signatures for immune monitoring that are less compromised by the timing and duration of integrated measures. PMID:22160692

  14. Mucosal and systemic T cell response in mice intragastrically infected with Neospora caninum tachyzoites

    PubMed Central

    2013-01-01

    The murine model has been widely used to study the host immune response to Neospora caninum. However, in most studies, the intraperitoneal route was preferentially used to establish infection. Here, C57BL/6 mice were infected with N. caninum tachyzoites by the intragastric route, as it more closely resembles the natural route of infection through the gastrointestinal tract. The elicited T-cell mediated immune response was evaluated in the intestinal epithelium and mesenteric lymph nodes (MLN). Early upon the parasitic challenge, IL-12 production by conventional and plasmacytoid dendritic cells was increased in MLN. Accordingly, increased proportions and numbers of TCRαβ+CD8+IFN-γ+ lymphocytes were detected, not only in the intestinal epithelium and MLN, but also in the spleen of the infected mice. In this organ, IFN-γ-producing TCRαβ+CD4+ T cells were also found to increase in the infected mice, however later than CD8+ T cells. Interestingly, splenic and MLN CD4+CD25+ T cells sorted from infected mice presented a suppressive activity on in vitro T cell proliferation and cytokine production above that of control counterparts. These results altogether indicate that, by producing IFN-γ, TCRαβ+CD8+ cells contribute for local and systemic host protection in the earliest days upon infection established through the gastrointestinal tract. Nevertheless, they also provide substantial evidence for a parasite-driven reinforcement of T regulatory cell function which may contribute for parasite persistence in the host and might represent an additional barrier to overcome towards effective vaccination. PMID:23937079

  15. Enhancing Human Immunodeficiency Virus-Specific CD8+ T Cell Responses with Heteroclitic Peptides

    PubMed Central

    Adegoke, Adeolu Oyemade; Grant, Michael David

    2015-01-01

    Human immunodeficiency virus (HIV)-specific CD8+ T cells play a critical role in containing HIV replication and delaying disease progression. However, HIV-specific CD8+ T cells become progressively more “exhausted” as chronic HIV infection proceeds. Symptoms of T cell exhaustion range from expression of inhibitory receptors and selective loss of cytokine production capacity through reduced proliferative potential, impaired differentiation into effector cells and increased susceptibility to apoptosis. While effective combination antiretroviral therapy (cART) durably reduces HIV viremia to undetectable levels, this alone does not restore the full pluripotency of HIV-specific CD8+ T cells. In a number of studies, a subset of peptide epitope variants categorized as heteroclitic, restimulated more potent cellular immune responses in vitro than did the native, immunizing peptides themselves. This property of heteroclitic peptides has been exploited in experimental cancer and chronic viral infection models to promote clearance of transformed cells and persistent viruses. In this review, we consider the possibility that heteroclitic peptides could improve the efficacy of therapeutic vaccines as part of HIV immunotherapy or eradication strategies. We review literature on heteroclitic peptides and illustrate their potential to beneficially modulate the nature of HIV-specific T cell responses toward those found in the small minority of HIV-infected, aviremic cART-naïve persons termed elite controllers or long-term non-progressors. Our review suggests that the efficacy of HIV vaccines could be improved by identification, testing, and incorporation of heteroclitic variants of native HIV peptide epitopes. PMID:26257743

  16. ANCA patients have T cells responsive to complementary PR-3 antigen

    PubMed Central

    Yang, Jiajin; Bautz, David J.; Lionaki, Sofia; Hogan, Susan L.; Chin, Hyunsook; Tisch, Roland M.; Schmitz, John L.; Pressler, Barrak M.; Jennette, J. Charles; Falk, Ronald J.; Preston, Gloria A.

    2009-01-01

    Some patients with proteinase 3 specific anti-neutrophil cytoplasmic autoantibodies (PR3-ANCA) also have antibodies that react to complementary-PR3 (cPR3), a protein encoded by the antisense RNA of the PR3 gene. To study whether patients with anti-cPR3 antibodies have cPR3-responsive memory T cells we selected conditions that allowed cultivation of memory cells but not naïve cells. About half of the patients were found to have CD4+TH1 memory cells responsive to the cPR3138-169-peptide; while only a third of the patients had HI-PR3 protein responsive T cells. A significant number of T cells from patients responded to cPR3138-169 peptide and to HI-PR3 protein by proliferation and/or secretion of IFN-γ, compared to healthy controls while there was no response to scrambled peptide. Cells responsive to cPR3138-169-peptide were not detected in MPO-ANCA patients suggesting that this response is specific. The HLADRB1* 15 allele was significantly overrepresented in our patient group and is predicted to bind cPR3138-169 peptide with high affinity. Regression analysis showed a significant likelihood that anti-cPR3 antibodies and cPR3-specific T cells coexist in individuals, consistent with an immunological history of encounter with a PR3-complementary protein. We suggest that the presence of cells reacting to potential complementary protein pairs might provide an alternative mechanism for auto-immune diseases. PMID:18596726

  17. A phorbol ester response element within the human T-cell receptor beta-chain enhancer.

    PubMed Central

    Prosser, H M; Wotton, D; Gegonne, A; Ghysdael, J; Wang, S; Speck, N A; Owen, M J

    1992-01-01

    The activity of the T-cell receptor beta-chain gene enhancer is increased by activators of the protein kinase C pathway during T-cell activation. Analysis of mutant enhancer constructs identified two elements, beta E2 and beta E3, conferring phorbol ester inducibility. Multimerized beta E2 acted in isolation as a phorbol ester-responsive element. Both beta E2 and beta E3, which contain a consensus Ets-binding site, were shown to bind directly to the product of the c-ets-1 protooncogene. Both regions also bound a second factor, core-binding factor. Mutation of the beta E2 Ets site abolished the inducibility of the beta E2 multimer. beta E2 and beta E3 Ets site mutations also profoundly affected activity and inducibility of the enhancer. In contrast, enhancer activity but not its inducibility was affected by mutation of the beta E2 core-binding factor site. Cotransfection studies showed that Ets-1 specifically repressed activity of the multimerized beta E2 element and the complete T-cell receptor beta-chain enhancer. These data show that the T-cell receptor beta-chain enhancer responds to protein kinase C-mediated activation signals via a functional domain, composed of two elements, which contains binding sites for Ets transcription factors and which is negatively regulated by Ets-1. Images PMID:1409722

  18. Interaction of CD31 with a heterophilic counterreceptor involved in downregulation of human T cell responses

    PubMed Central

    1996-01-01

    CD31 is a 130-kD glycoprotein of the immunoglobulin (Ig) superfamily expressed on the surface of endothelial cells, platelets, and several leukocyte subsets. Previous reports indicated that CD31 can mediate intercellular adhesion via both homophilic and heterophilic interaction mechanisms. Using a soluble recombinant CD31-Ig fusion protein (CD31 receptor globulin [Rg]), we demonstrate here that human CD31- T lymphocytes and CD4+CD31- T cell clones express a heterophilic CD31 ligand that is upregulated 18 h after activation. Interaction of CD31Rg with CD31- T helper cell (Th) clones was divalent cation independent but could be blocked by heparin, thus indicating that the CD31 counterreceptor on T cells can be distinguished from the ligands identified on other cell types. Moreover, a single chain protein of 120 kD was precipitated by CD31Rg from the lysates of CD31- Th clones. CD31Rg completely downregulated the proliferative response and cytokine production (interleukin-4, interferon-gamma, and tumor necrosis factor- alpha) of CD31- Th clones when the cells were maximally stimulated via immobilized CD3 monoclonal antibody. These results suggest that interaction of CD31 with a heterophilic counterreceptor on T lymphocytes can interfere with a positive regulatory pathway of T cell activation, or directly signal T cells to downregulate immune function. PMID:8691148

  19. Tumor-associated neutrophils stimulate T cell responses in early-stage human lung cancer

    PubMed Central

    Eruslanov, Evgeniy B.; Bhojnagarwala, Pratik S.; Quatromoni, Jon G.; Stephen, Tom Li; Ranganathan, Anjana; Deshpande, Charuhas; Akimova, Tatiana; Vachani, Anil; Litzky, Leslie; Hancock, Wayne W.; Conejo-Garcia, José R.; Feldman, Michael; Albelda, Steven M.; Singhal, Sunil

    2014-01-01

    Infiltrating inflammatory cells are highly prevalent within the tumor microenvironment and mediate many processes associated with tumor progression; however, the contribution of specific populations remains unclear. For example, the nature and function of tumor-associated neutrophils (TANs) in the cancer microenvironment is largely unknown. The goal of this study was to provide a phenotypic and functional characterization of TANs in surgically resected lung cancer patients. We found that TANs constituted 5%–25% of cells isolated from the digested human lung tumors. Compared with blood neutrophils, TANs displayed an activated phenotype (CD62LloCD54hi) with a distinct repertoire of chemokine receptors that included CCR5, CCR7, CXCR3, and CXCR4. TANs produced substantial quantities of the proinflammatory factors MCP-1, IL-8, MIP-1α, and IL-6, as well as the antiinflammatory IL-1R antagonist. Functionally, both TANs and neutrophils isolated from distant nonmalignant lung tissue were able to stimulate T cell proliferation and IFN-γ release. Cross-talk between TANs and activated T cells led to substantial upregulation of CD54, CD86, OX40L, and 4-1BBL costimulatory molecules on the neutrophil surface, which bolstered T cell proliferation in a positive-feedback loop. Together our results demonstrate that in the earliest stages of lung cancer, TANs are not immunosuppressive, but rather stimulate T cell responses. PMID:25384214

  20. Dose-Responsive Gene Expression in Suberoylanilide Hydroxamic Acid (SAHA) Treated Resting CD4+ T Cells

    PubMed Central

    Reardon, Brian; Beliakova-Bethell, Nadejda; Spina, Celsa A.; Singhania, Akul; Margolis, David M.; Richman, Douglas R.; Woelk, Christopher H.

    2015-01-01

    Design Persistent latently infected CD4+ T cells represent a major obstacle to HIV eradication. Histone deacetylase inhibitors (HDACis) are a proposed activation therapy. However, off-target effects on expression in host immune cells are poorly understood. We hypothesized that HDACi-modulated genes would be best identified with dose-response analysis. Methods Resting primary CD4+ T cells were treated with 0.34, 1, 3, or 10 μM of the HDACi, SAHA, for 24 hours and subjected to microarray gene expression analysis. Genes with dose-correlated expression were filtered to identify a subset with consistent up or downregulation at each SAHA dose. Histone modifications were characterized in 6 SAHA dose-responsive genes by chromatin immunoprecipitation (ChIP-RT-qPCR). Results A large number of genes were shown to be up (N=657) or downregulated (N=725) by SAHA in a dose-responsive manner (FDR p-value < 0.05, fold change ≥ |2|). Several genes (CTNNAL1, DPEP2, H1F0, IRGM, PHF15, and SELL) are potential in vivo biomarkers of SAHA activity. SAHA dose-responsive genes included transcription factors, HIV restriction factors, histone methyltransferases, and host proteins that interact with HIV. Pathway analysis suggested net downregulation of T cell activation with increasing SAHA dose. Histone acetylation was not correlated with host gene expression, but plausible alternative mechanisms for SAHA-modulated gene expression were identified. Conclusions Numerous genes in CD4+ T cells are modulated by SAHA in a dose-responsive manner, including genes that may negatively influence HIV activation from latency. Our study suggests that SAHA influences gene expression through a confluence of several mechanisms, including histone modification, and altered expression and activity of transcription factors. PMID:26258524

  1. Stronger inflammatory/cytotoxic T cell response in women identified by microarray analysis

    PubMed Central

    Hewagama, Anura; Patel, Dipak; Yarlagadda, Sushma; Strickland, Faith M.; Richardson, Bruce C.

    2009-01-01

    Women develop chronic inflammatory autoimmune diseases more often than men. The mechanisms causing the increased susceptibility are incompletely understood. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T cell response in women than men. Microarrays were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days following a single stimulation only 25% of differentially expressed, gender-biased genes were expressed at higher levels in women. In contrast, following restimulation 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women and among the immune response genes, the inflammatory/cytotoxic effector genes interferon gamma (IFNG), lymphotoxin beta (LTB), granzyme A (GZMA), interleukin-12 receptor beta2 (IL12RB2), and granulysin (GNLY) were among those overexpressed to the greatest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half the overexpressed immune genes in women, and in <10% of the male biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men. PMID:19279650

  2. Stronger inflammatory/cytotoxic T-cell response in women identified by microarray analysis.

    PubMed

    Hewagama, A; Patel, D; Yarlagadda, S; Strickland, F M; Richardson, B C

    2009-07-01

    Women develop chronic inflammatory autoimmune diseases more often than men. The mechanisms causing the increased susceptibility are incompletely understood. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T-cell response in women than in men. Microarrays were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days after a single stimulation, only 25% of differentially expressed, gender-biased genes were expressed at higher levels in women. In contrast, after restimulation, 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women and among the immune response genes, the inflammatory/cytotoxic effector genes interferon-gamma (IFN-gamma), lymphotoxin beta (LTbeta), granzyme A (GZMA), interleukin-12 receptor beta2 (IL12Rbeta2), and granulysin (GNLY) were among those overexpressed to the highest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half the overexpressed immune genes in women, and in <10% of the male-biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men.

  3. Polyfunctional cytokine production by central memory T cells from cattle in response to Mycobacterium bovis infection and BCG vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyfunctional T cells simultaneously produce IFN-gamma, IL-2 and TNF-alpha and play relevant roles in several chronic infections, including TB. Mycobacterium bovis infection of cattle elicits ex vivo polyfunctional T cell responses. Vaccine-elicited IFN-gamma Tcm (CD4+ CD45RO+ CCR7+) responses corr...

  4. ICAM-1–dependent tuning of memory CD8 T-cell responses following acute infection

    PubMed Central

    Cox, Maureen A.; Barnum, Scott R.; Bullard, Daniel C.; Zajac, Allan J.

    2013-01-01

    CD8 T-cell responses are critical for protection against intracellular pathogens and tumors. The induction and properties of these responses are governed by a series of integrated processes that rely heavily on cell–cell interactions. Intercellular adhesion molecule (ICAM)-1 functions to enhance the strength of antigenic stimulation, extend the duration of contact with antigen-presenting cells, and augment cytokine signals, which are all factors that influence peripheral CD8 T-cell differentiation. Although previous studies suggest that ICAM-1 is essential for establishing memory T-cell populations following peptide immunization, the roles of ICAM-1 in antiviral cellular immunity are less well understood. Here we show that, following a prototypic acute viral infection, the formation and maintenance of memory-phenotype CD127hi, KLRG-1lo CD8 T cells does not require ICAM-1. Nevertheless, ICAM-1 expression on nonlymphocytes dictates the phenotypic and functional attributes of the antiviral CD8 T-cell populations that develop and promotes the gradual attrition of residual effector-like CD127lo, KLRG-1hi CD8 T cells during the memory phase of the response. Although memory T cells do emerge and are maintained if ICAM-1 expression is abolished, the secondary proliferative capacity of these T cells is severely curtailed. Collectively, these studies reveal potential dual roles for ICAM-1 in both promoting the decay of effector responses and programming the sensitivity of memory CD8 T cells to secondary stimuli. PMID:23297203

  5. Vaccine Targeting of Subdominant CD8+ T Cell Epitopes Increases the Breadth of the T Cell Response upon Viral Challenge, but May Impair Immediate Virus Control.

    PubMed

    Steffensen, Maria A; Pedersen, Louise H; Jahn, Marie L; Nielsen, Karen N; Christensen, Jan P; Thomsen, Allan R

    2016-03-15

    As a result of the difficulties in making efficient vaccines against genetically unstable viruses such as HIV, it has been suggested that future vaccines should preferentially target subdominant epitopes, the idea being that this should allow a greater breadth of the induced T cell response and, hence, a greater efficiency in controlling escape variants. However, to our knowledge the evidence supporting this concept is limited at best. To improve upon this, we used the murine lymphocytic choriomeningitis virus model and adenoviral vectors to compare a vaccine expressing unmodified Ag to a vaccine expressing the same Ag without its immunodominant epitope. We found that removal of the dominant epitope allowed the induction of CD8(+) T cell responses targeting at least two otherwise subdominant epitopes. Importantly, the overall magnitude of the induced T cell responses was similar, allowing us to directly compare the efficiency of these vaccines. Doing this, we observed that mice vaccinated with the vaccine expressing unmodified Ag more efficiently controlled an acute viral challenge. In the course of a more chronic viral infection, mice vaccinated using the vaccine targeting subdominant epitopes caught up with the conventionally vaccinated mice, and analysis of the breadth of the CD8(+) T cell response revealed that this was notably greater in the former mice. However, under the conditions of our studies, we never saw any functional advantage of this. This may represent a limitation of our model, but clearly our findings underscore the importance of carefully weighing the pros and cons of changes in epitope targeting before any implementation.

  6. Interleukin-7 Modulates Anti-Tumor CD8+ T Cell Responses via Its Action on Host Cells

    PubMed Central

    Deiser, Katrin; Stoycheva, Diana; Bank, Ute; Blankenstein, Thomas; Schüler, Thomas

    2016-01-01

    The adoptive transfer of antigen-specific CD8+ T cells is a promising approach for the treatment of chronic viral and malignant diseases. In order to improve adoptive T cell therapy (ATT) of cancer, recent strategies aim at the antibody-based blockade of immunosuppressive signaling pathways in CD8+ T cells. Alternatively, adjuvant effects of immunostimulatory cytokines might be exploited to improve therapeutic CD8+ T cell responses. For example, Interleukin-7 (IL-7) is a potent growth, activation and survival factor for CD8+ T cells that can be used to improve virus- and tumor-specific CD8+ T cell responses. Although direct IL-7 effects on CD8+ T cells were studied extensively in numerous models, the contribution of IL-7 receptor-competent (IL-7R+) host cells remained unclear. In the current study we provide evidence that CD8+ T cell-mediated tumor rejection in response to recombinant IL-7 (rIL-7) therapy is strictly dependent on IL-7R+ host cells. On the contrary, CD8+ T cell expansion is independent of host IL-7R expression. If, however, rIL-7 therapy and peptide vaccination are combined, host IL-7R signaling is crucial for CD8+ T cell expansion. Unexpectedly, maximum CD8+ T cell expansion relies mainly on IL-7R signaling in non-hematopoietic host cells, similar to the massive accumulation of dendritic cells and granulocytes. In summary, we provide evidence that IL-7R+ host cells are major targets of rIL-7 that modulate therapeutic CD8+ T cell responses and the outcome of rIL-7-assisted ATT. This knowledge may have important implications for the design and optimization of clinical ATT protocols. PMID:27447484

  7. The Regulation of CD4(+) T Cell Responses during Protozoan Infections.

    PubMed

    Engwerda, Christian R; Ng, Susanna S; Bunn, Patrick T

    2014-01-01

    CD4(+) T cells are critical for defense against protozoan parasites. Intracellular protozoan parasite infections generally require the development of a Th1 cell response, characterized by the production of IFNγ and TNF that are critical for the generation of microbicidal molecules by phagocytes, as well as the expression of cytokines and cell surface molecules needed to generate cytolytic CD8(+) T cells that can recognize and kill infected host cells. Over the past 25 years, much has been learnt about the molecular and cellular components necessary for the generation of Th1 cell responses, and it has become clear that these responses need to be tightly controlled to prevent disease. However, our understanding of the immunoregulatory mechanisms activated during infection is still not complete. Furthermore, it is apparent that although these mechanisms are critical to prevent inflammation, they can also promote parasite persistence and development of disease. Here, we review how CD4(+) T cells are controlled during protozoan infections and how these regulatory mechanisms can influence parasite growth and disease outcome.

  8. TRAF3 regulates the effector function of regulatory T cells and humoral immune responses

    PubMed Central

    Chang, Jae-Hoon; Hu, Hongbo; Jin, Jin; Puebla-Osorio, Nahum; Xiao, Yichuan; Gilbert, Brian E.; Brink, Robert; Ullrich, Stephen E.

    2014-01-01

    Regulatory T cells (Treg cells) control different aspects of immune responses, but how the effector functions of Treg cells are regulated is incompletely understood. Here we identified TNF receptor–associated factor 3 (TRAF3) as a regulator of Treg cell function. Treg cell–specific ablation of TRAF3 impaired CD4 T cell homeostasis, characterized by an increase in the Th1 type of effector/memory T cells. Moreover, the ablation of TRAF3 in Treg cells resulted in increased antigen-stimulated activation of follicular T helper cells (TFH cells), coupled with heightened formation of germinal centers and production of high-affinity IgG antibodies. Although the loss of TRAF3 did not reduce the overall frequency of Treg cells, it attenuated the antigen-stimulated production of follicular Treg cells (TFR cells). TRAF3 signaling in Treg cells was required to maintain high level expression of inducible co-stimulator (ICOS), which in turn was required for TFR cell generation and inhibition of antibody responses. These findings establish TRAF3 as a mediator of Treg cell function in the regulation of antibody responses and suggest a role for TRAF3 in mediating ICOS expression in Treg cells. PMID:24378539

  9. T cells translate individual, quantal activation into collective, analog cytokine responses via time-integrated feedbacks

    PubMed Central

    Tkach, Karen E; Barik, Debashis; Voisinne, Guillaume; Malandro, Nicole; Hathorn, Matthew M; Cotari, Jesse W; Vogel, Robert; Merghoub, Taha; Wolchok, Jedd; Krichevsky, Oleg; Altan-Bonnet, Grégoire

    2014-01-01

    Variability within isogenic T cell populations yields heterogeneous ‘local’ signaling responses to shared antigenic stimuli, but responding clones may communicate ‘global’ antigen load through paracrine messengers, such as cytokines. Such coordination of individual cell responses within multicellular populations is critical for accurate collective reactions to shared environmental cues. However, cytokine production may saturate as a function of antigen input, or be dominated by the precursor frequency of antigen-specific T cells. Surprisingly, we found that T cells scale their collective output of IL-2 to total antigen input over a large dynamic range, independently of population size. Through experimental quantitation and computational modeling, we demonstrate that this scaling is enforced by an inhibitory cross-talk between antigen and IL-2 signaling, and a nonlinear acceleration of IL-2 secretion per cell. Our study reveals how time-integration of these regulatory loops within individual cell signaling generates scaled collective responses and can be leveraged for immune monitoring. DOI: http://dx.doi.org/10.7554/eLife.01944.001 PMID:24719192

  10. Public T cell receptors confer high-avidity CD4 responses to HIV controllers

    PubMed Central

    Galperin, Moran; Lambotte, Olivier; Gras, Stéphanie; Lim, Annick; Mukhopadhyay, Madhura; Campbell, Kristy-Anne; Lemercier, Brigitte; Claireaux, Mathieu; Hendou, Samia; Lechat, Pierre; de Truchis, Pierre; Boufassa, Faroudy; Rossjohn, Jamie; Delfraissy, Jean-François; Arenzana-Seisdedos, Fernando; Chakrabarti, Lisa A.

    2016-01-01

    The rare patients who are able to spontaneously control HIV replication in the absence of therapy show signs of a particularly efficient cellular immune response. To identify the molecular determinants that underlie this response, we characterized the T cell receptor (TCR) repertoire directed at Gag293, the most immunoprevalent CD4 epitope in the HIV-1 capsid. HIV controllers from the ANRS CODEX cohort showed a highly skewed TCR repertoire that was characterized by a predominance of TRAV24 and TRBV2 variable genes, shared CDR3 motifs, and a high frequency of public clonotypes. The most prevalent public clonotypes generated TCRs with affinities at the higher end of values reported for naturally occurring TCRs. The high-affinity Gag293-specific TCRs were cross-restricted by up to 5 distinct HLA-DR alleles, accounting for the expression of these TCRs in HIV controllers of diverse genetic backgrounds. Transfer of these TCRs to healthy donor CD4+ T cells conferred high antigen sensitivity and polyfunctionality, thus recapitulating key features of the controller CD4 response. Transfer of a high-affinity Gag293-specific TCR also redirected CD8+ T cells to target HIV-1 capsid via nonconventional MHC II restriction. Together, these findings indicate that TCR clonotypes with superior functions are associated with HIV control. Amplification or transfer of such clonotypes may contribute to immunotherapeutic approaches aiming at a functional HIV cure. PMID:27111229

  11. Induction of Gag-Specific CD4 T Cell Responses during Acute HIV Infection Is Associated with Improved Viral Control

    PubMed Central

    Schieffer, Miriam; Jessen, Heiko K.; Oster, Alexander F.; Pissani, Franco; Soghoian, Damien Z.; Lu, Richard; Jessen, Arne B.; Zedlack, Carmen; Schultz, Bruce T.; Davis, Isaiah; Ranasinghe, Srinika; Rosenberg, Eric S.; Alter, Galit; Schumann, Ralf R.

    2014-01-01

    ABSTRACT Effector CD4 T cell responses have been shown to be critically involved in the containment and clearance of viral pathogens. However, their involvement in the pathogenesis of HIV infection is less clear, given their additional role as preferred viral targets. We previously demonstrated that the presence of HIV-specific CD4 T cell responses is somewhat associated with HIV control and that specific CD4 T cell functions, such as direct cytolytic activity, can contribute to control of HIV viremia. However, little is known about how the induction of HIV-specific CD4 T cell responses during acute HIV infection influences disease progression and whether responses induced during the early phase of infection are preferentially depleted. We therefore longitudinally assessed, in a cohort of 55 acutely HIV-infected individuals, HIV-specific CD4 T cell responses from acute to chronic infection. Interestingly, we found that the breadth, magnitude, and protein dominance of HIV-specific CD4 T cell responses remained remarkably stable over time. Moreover, we found that the epitopes targeted at a high frequency in acute HIV infection were recognized at the same frequency by HIV-specific CD4 T cells in chronic HIV infection. Interestingly the induction of Gag-specific CD4 T cell responses in acute HIV infection was significantly inversely correlated with viral set point in chronic HIV infection (R = −0.5; P = 0.03), while the cumulative contribution of Env-specific CD4 T cell responses showed the reverse effect. Moreover, individuals with HIV-specific CD4 T cell responses dominantly targeting Gag over Env in acute HIV infection remained off antiretroviral therapy significantly longer (P = 0.03; log rank). Thus, our data suggest that the induction of HIV-specific CD4 T cell responses during acute HIV infection is beneficial overall and does not fuel disease progression. IMPORTANCE CD4 T cells are critical for the clearance and control of viral infections. However, HIV

  12. Early CD4+ T Cell Responses Are Associated with Subsequent CD8+ T Cell Responses to an rAd5-Based Prophylactic Prime-Boost HIV Vaccine Strategy

    PubMed Central

    Lhomme, Edouard; Richert, Laura; Moodie, Zoe; Pasin, Chloé; Kalams, Spyros A.; Morgan, Cecilia; Self, Steve; De Rosa, Stephen C.; Thiébaut, Rodolphe

    2016-01-01

    Introduction Initial evaluation of a candidate vaccine against HIV includes an assessment of the vaccine’s ability to generate immune responses. However, the dynamics of vaccine-induced immune responses are unclear. We hypothesized that the IFN-γ producing cytotoxic CD8+ (CD8+ IFN-γ+) T cell responses could be predicted by early IL-2 producing CD4+ (CD4+ IL-2+) helper T cell responses, and we evaluated this hypothesis using data from a phase I/II prophylactic HIV vaccine trial. The objective was to assess the dynamics and correlations between CD4+ IL-2+ T cell and CD8+ IFN-γ+ T cell responses after vaccination with a recombinant adenoviral serotype 5 (rAd5) HIV vaccine. Methods We analyzed data from the HVTN 068 HIV vaccine trial, which evaluated the immunogenicity of two different strategies for prime and boost vaccination (rAd5-rAd5 vaccine versus DNA-rAd5) in 66 healthy volunteers. Spearman correlations between immunogenicity markers across time-points were calculated. CD8+ IFN-γ+ T cell response in the rAd5-rAd5 arm was modeled as a function of CD4+ IL-2+ T cell response and time using mixed effects regression models. Results Moderate to high correlations (r = 0.48–0.76) were observed in the rAd5-rAd5 arm between the CD4+ IL-2+ T cell response at week 2 and later CD8+ IFN-γ+ T cell responses (weeks 2–52). Regression models confirmed this relationship with a significant association between the two markers: for a 1.0% increase in CD4+ IL-2+ T cells at week 2 post-prime, a 0.3% increase in CD8+ IFN-γ+ T cell responses across subsequent time points, including post-boost time points, was observed (p<0.01). Conclusion These results suggest an early and leading role of CD4+ T cells in the cellular response to the rAd5-rAd5 vaccine and in particular the stimulation of cytotoxic CD8+ T cell responses. These results could inform better timing of CD4+ T cell measurements in future clinical trials. PMID:27124598

  13. Skin inflammation arising from cutaneous regulatory T cell deficiency leads to impaired viral immune responses.

    PubMed

    Freyschmidt, Eva-Jasmin; Mathias, Clinton B; Diaz, Natalia; MacArthur, Daniel H; Laouar, Amale; Manjunath, Narasimhaswamy; Hofer, Matthias D; Wurbel, Marc-Andre; Campbell, James J; Chatila, Talal A; Oettgen, Hans C

    2010-07-15

    Individuals with atopic dermatitis immunized with the small pox vaccine, vaccinia virus (VV), are susceptible to eczema vaccinatum (EV), a potentially fatal disseminated infection. Dysfunction of Forkhead box P3 (FoxP3)-positive regulatory T cells (Treg) has been implicated in the pathogenesis of atopic dermatitis. To test whether Treg deficiency predisposes to EV, we percutaneously VV infected FoxP3-deficient (FoxP3(KO)) mice, which completely lack FoxP3(+) Treg. These animals generated both fewer VV-specific CD8(+) effector T cells and IFN-gamma-producing CD8(+) T cells than controls, had higher viral loads, and exhibited abnormal Th2-polarized responses to the virus. To focus on the consequences of Treg deficiency confined to the skin, we generated mixed CCR4(KO) FoxP3(KO) bone marrow (CCR4/FoxP3) chimeras in which skin, but not other tissues or central lymphoid organs, lack Treg. Like FoxP3(KO) mice, the chimeras had impaired VV-specific effector T cell responses and higher viral loads. Skin cytokine expression was significantly altered in infected chimeras compared with controls. Levels of the antiviral cytokines, type I and II IFNs and IL-12, were reduced, whereas expression of the proinflammatory cytokines, IL-6, IL-10, TGF-beta, and IL-23, was increased. Importantly, infection of CCR4/FoxP3 chimeras by a noncutaneous route (i.p.) induced immune responses comparable to controls. Our findings implicate allergic skin inflammation resulting from local Treg deficiency in the pathogenesis of EV.

  14. Mathematical Model Reveals the Role of Memory CD8 T Cell Populations in Recall Responses to Influenza

    PubMed Central

    Zarnitsyna, Veronika I.; Handel, Andreas; McMaster, Sean R.; Hayward, Sarah L.; Kohlmeier, Jacob E.; Antia, Rustom

    2016-01-01

    The current influenza vaccine provides narrow protection against the strains included in the vaccine, and needs to be reformulated every few years in response to the constantly evolving new strains. Novel approaches are directed toward developing vaccines that provide broader protection by targeting B and T cell epitopes that are conserved between different strains of the virus. In this paper, we focus on developing mathematical models to explore the CD8 T cell responses to influenza, how they can be boosted, and the conditions under which they contribute to protection. Our models suggest that the interplay between spatial heterogeneity (with the virus infecting the respiratory tract and the immune response being generated in the secondary lymphoid organs) and T cell differentiation (with proliferation occurring in the lymphoid organs giving rise to a subpopulation of resident T cells in the respiratory tract) is the key to understand the dynamics of protection afforded by the CD8 T cell response to influenza. Our results suggest that the time lag for the generation of resident T cells in the respiratory tract and their rate of decay following infection are the key factors that limit the efficacy of CD8 T cell responses. The models predict that an increase in the level of central memory T cells leads to a gradual decrease in the viral load, and, in contrast, there is a sharper protection threshold for the relationship between the size of the population of resident T cells and protection. The models also suggest that repeated natural influenza infections cause the number of central memory CD8 T cells and the peak number of resident memory CD8 T cells to reach their plateaus, and while the former is maintained, the latter decays with time since the most recent infection. PMID:27242779

  15. Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

    PubMed Central

    Fiume, Giuseppe; Scialdone, Annarita; Albano, Francesco; Rossi, Annalisa; Maria Tuccillo, Franca; Rea, Domenica; Palmieri, Camillo; Caiazzo, Elisabetta; Cicala, Carla; Bellevicine, Claudio; Falcone, Cristina; Vecchio, Eleonora; Pisano, Antonio; Ceglia, Simona; Mimmi, Selena; Iaccino, Enrico; Laurentiis, Annamaria de; Pontoriero, Marilena; Agosti, Valter; Troncone, Giancarlo; Mignogna, Chiara; Palma, Giuseppe; Arra, Claudio; Mallardo, Massimo; Maria Buonaguro, Franco; Scala, Giuseppe; Quinto, Ileana

    2015-01-01

    Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4+ and CD8+ T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation. PMID:26343909

  16. Idelalisib and caffeine reduce suppression of T cell responses mediated by activated chronic lymphocytic leukemia cells

    PubMed Central

    Hock, Barry D.; MacPherson, Sean A.; McKenzie, Judith L.

    2017-01-01

    Chronic lymphocytic leukemia (CLL) is associated with T cell dysfunction. Activated CLL cells are found within the lymphoid tumor micro-environment and overcoming immuno-suppression induced by these cells may improve anti-CLL immune responses. However, the mechanisms by which activated CLL cells inhibit T cell responses, and reagents targeting such mechanisms have not been identified. Here we demonstrate that the ability of in vitro activated CLL cells to suppress T cell proliferation is not reversed by the presence of ecto-nuclease inhibitors or blockade of IL-10, PD-1 and CTLA-4 pathways. Caffeine is both an adenosine receptor antagonist and a phosphatidylinositol-3-kinase, p110δ (PI3Kδ) inhibitor and, at physiologically relevant levels, significantly reversed suppression. Significant reversal of suppression was also observed with the PI3Kδ specific inhibitor Idelalisib but not with adenosine receptor specific antagonists. Furthermore, addition of caffeine or Idelalisib to activated CLL cells significantly inhibited phosphorylation of AKT, a downstream kinase of PI3K, but did not affect CLL viability. These results suggest that caffeine, in common with Idelalisib, reduces the immuno-suppressive activity of activated CLL cells by inhibiting PI3Kδ. These findings raise the possibility that these compounds may provide a useful therapeutic adjunct by reducing immuno-suppression within the tumor micro-environment of CLL. PMID:28257435

  17. Donor exosomes rather than passenger leukocytes initiate alloreactive T cell responses after transplantation

    PubMed Central

    Marino, Jose; Babiker-Mohamed, Mohamed H.; Crosby-Bertorini, Patrick; Paster, Joshua T.; LeGuern, Christian; Germana, Sharon; Abdi, Reza; Uehara, Mayuko; Kim, James I.; Markmann, James F.; Tocco, Georges; Benichou, Gilles

    2016-01-01

    Transplantation of allogeneic organs and tissues represents a lifesaving procedure for a variety of patients affected with end-stage diseases. Although current immunosuppressive therapy prevents early acute rejection, it is associated with nephrotoxicity and increased risks for infection and neoplasia. This stresses the need for selective immune-based therapies relying on manipulation of lymphocyte recognition of donor antigens. The passenger leukocyte theory states that allograft rejection is initiated by recipient T cells recognizing donor major histocompatibility complex (MHC) molecules displayed on graft leukocytes migrating to the host’s lymphoid organs. We revisited this concept in mice transplanted with allogeneic skin, heart, or islet grafts using imaging flow cytometry. We observed no donor cells in the lymph nodes and spleen of skin-grafted mice, but we found high numbers of recipient cells displaying allogeneic MHC molecules (cross-dressed) acquired from donor microvesicles (exosomes). After heart or islet transplantation, we observed few donor leukocytes (100 per million) but large numbers of recipient cells cross-dressed with donor MHC (>90,000 per million). Last, we showed that purified allogeneic exosomes induced proinflammatory alloimmune responses by T cells in vitro and in vivo. Collectively, these results suggest that recipient antigen-presenting cells cross-dressed with donor MHC rather than passenger leukocytes trigger T cell responses after allotransplantation. PMID:27942611

  18. Exposure to inhaled isobutyl nitrite reduces T cell-dependent responsiveness

    SciTech Connect

    Soderberg, L.S.F.; Barnett, J.B. )

    1991-03-11

    Isobutyl nitrite is a drug of abuse popular among male homosexuals and among adolescents. In order to approximate the nitrite exposures of inhalant abusers, mice were treated with 900 ppm isobutyl nitrite in an inhalation chamber for 45 min per day for 14 days. At 72 hr after the last exposure, mice were assayed for immune competence. Under these conditions, mice gained only half the weight of mice exposed to air. The spleens of nitrite exposed mice weighed 15% less and had 24% fewer cells per spleen than controls. Adjusted for equal cell numbers, T cell mitogenic and allogeneic proliferative responses were significantly reduce by 33% and 47%, respectively. Unstimulated spleen cells had elevated levels of IL-2 transcription following exposure to isobutyl nitrite suggesting that nitrite inhalation caused a nonspecific induction of T cells. In contrast, B cell proliferative responses to LPS were unaltered. Exposure to the nitrite reduced the frequency of T-dependent antibody plaque-forming cells (PFC) by 63% and the total number of reduced by 60% after as few as five daily exposures to isobutyl nitrite. Therefore, the data suggest that habitual inhalation of isobutyl nitrite impairs immune competence and that toxicity appears to be directed toward T cell functions.

  19. Otud7b facilitates T cell activation and inflammatory responses by regulating Zap70 ubiquitination

    PubMed Central

    Hu, Hongbo; Wang, Hui; Xiao, Yichuan; Jin, Jin; Chang, Jae-Hoon; Zou, Qiang; Xie, Xiaoping; Cheng, Xuhong

    2016-01-01

    Signal transduction from the T cell receptor (TCR) is crucial for T cell–mediated immune responses and, when deregulated, also contributes to the development of autoimmunity. How TCR signaling is regulated is incompletely understood. In this study, we demonstrate a ubiquitin-dependent mechanism in which the deubiquitinase Otud7b has a crucial role in facilitating TCR signaling. Upon TCR ligation, Otud7b is rapidly recruited to the tyrosine kinase Zap70, a central mediator of TCR-proximal signaling. Otud7b deficiency attenuates the activation of Zap70 and its downstream pathways and impairs T cell activation and differentiation, rendering mice refractory to T cell–mediated autoimmune and inflammatory responses. Otud7b facilitated Zap70 activation by deubiquitinating Zap70, thus preventing the association of Zap70 with the negative-regulatory phosphatases Sts1 and Sts2. These findings establish Otud7b as a positive regulator of TCR-proximal signaling and T cell activation, highlighting the importance of deubiquitination in regulating Zap70 function. PMID:26903241

  20. [The Role of Regulatory T-cells in Antitumor Immune Response].

    PubMed

    Klabusay, M

    2015-01-01

    Regulatory T-lymphocytes (Treg) are essential for regulation of immune homeostasis and prevention of autoimmune disease development. Regulatory T-cells prevent the onset of autoimmune diseases; they keep immune homeostasis and modulate immune response during infection. Their activity is precisely controlled. Regulatory T-cells belong to one group of immune cells, which can support tumor survival and growth. They realize their function through inhibition of effector T-cells and by regulation of tumor microenvironment through production of various soluble factors. Many publications have proven that the amount of Treg cells is elevated in both solid tumors and in hematologic malignancies. Nevertheless, little is known about mechanisms, which allow increase and maintenance of elevated Treg cells in cancer patients. In this review, we will focus, among others, on the description of function and phenotype of Treg cells, their modulation of humoral immune response and interaction with cancer stem cells. Current development of modern tumor immunotherapy allows new possibilities of influencing Treg cells function.

  1. TLR2 engagement on CD4(+) T cells enhances effector functions and protective responses to Mycobacterium tuberculosis.

    PubMed

    Reba, Scott M; Li, Qing; Onwuzulike, Sophia; Ding, Xuedong; Karim, Ahmad F; Hernandez, Yeritza; Fulton, Scott A; Harding, Clifford V; Lancioni, Christina L; Nagy, Nancy; Rodriguez, Myriam E; Wearsch, Pamela A; Rojas, Roxana E

    2014-05-01

    We have previously demonstrated that mycobacterial lipoproteins engage TLR2 on human CD4(+) T cells and upregulate TCR-triggered IFN-γ secretion and cell proliferation in vitro. Here we examined the role of CD4(+) T-cell-expressed TLR2 in Mycobacterium tuberculosis (MTB) Ag-specific T-cell priming and in protection against MTB infection in vivo. Like their human counterparts, mouse CD4(+) T cells express TLR2 and respond to TLR2 costimulation in vitro. This Th1-like response was observed in the context of both polyclonal and Ag-specific TCR stimulation. To evaluate the role of T-cell TLR2 in priming of CD4(+) T cells in vivo, naive MTB Ag85B-specific TCR transgenic CD4(+) T cells (P25 TCR-Tg) were adoptively transferred into Tlr2(-/-) recipient C57BL/6 mice that were then immunized with Ag85B and with or without TLR2 ligand Pam3 Cys-SKKKK. TLR2 engagement during priming resulted in increased numbers of IFN-γ-secreting P25 TCR-Tg T cells 1 week after immunization. P25 TCR-Tg T cells stimulated in vitro via TCR and TLR2 conferred more protection than T cells stimulated via TCR alone when adoptively transferred before MTB infection. Our findings indicate that TLR2 engagement on CD4(+) T cells increases MTB Ag-specific responses and may contribute to protection against MTB infection.

  2. Bim is required for T-cell allogeneic responses and graft-versus-host disease in vivo.

    PubMed

    Yu, Yu; Yu, Jing; Iclozan, Cristina; Kaosaard, Kane; Anasetti, Claudio; Yu, Xue-Zhong

    2012-01-01

    Bim, a BH3-only Bcl-2-family protein, is essential for T-cell negative selection in the thymus as well as for the death of activated T cells in the periphery. The role of Bim has been extensively studied in T-cell responses to self-antigens and viral infections. Recent findings on Bim in autoimmunity triggered our interest in investigating whether Bim may play a role in another disease with inflammatory symptoms as graft-versus-host disease (GVHD). Here we report that Bim is required for optimal T-cell responses to alloantigens in vivo and for the development of GVHD. Using murine models of allogeneic bone marrow transplantation (BMT), we found that donor T cells deficient for Bim are impaired in the induction of GVHD primarily due to a significant defect in T cell activation and expansion in vivo. Upon TCR engagement, Bim(-/-) T cells exhibited selective defects in CD69 expression and phosphorylation of PLCγ1. Our studies uncover a novel aspect of Bim function in T-cell activation with important implications in understanding the mechanisms of T-cell activation and tolerance under allogeneic transplantation.

  3. ICOS expression by effector T cells influences the ability of regulatory T cells to inhibit anti-chromatin B cell responses in recipient mice.

    PubMed

    Hondowicz, Brian D; Batheja, Amrita O; Metzgar, Michele H; Caton, Andrew J; Erikson, Jan

    2010-06-01

    T regulatory cells are critical for the prevention of autoimmunity. Specifically, Treg cells can control anti-chromatin antibody production in vivo, and this correlates with decreased ICOS expression on CD4(+) T helper cells. Here we test the significance of high ICOS expression by T effector cells, firstly in terms of the anti-chromatin B cell response, and secondly on the ability of Treg cells to suppress T cell help. We bred CD4(+) T cell receptor transgenic mice with mice that carry the Roquin(san/san) mutation. The Roquin gene functions to limit ICOS mRNA such that CD4 T cells from mutant mice express elevated ICOS. Using an in vivo model, TS1.Roquin(san/san) Th cells were compared with wild-type TS1 Th cells with regard to their ability to help anti-chromatin B cells in the presence or absence of Treg cells. Both TS1 and TS1.Roquin(san/san) Th cells induced anti-chromatin IgM(a) antibodies, but the TS1.Roquin(san/san) Th cells resulted in the recovery of more class-switched and germinal center B cells. Neither source of Th cells were capable of inducing long-lived autoantibodies. Treg cells completely suppressed anti-chromatin IgM(a) antibody production and reduced anti-chromatin B cell recovery induced by TS1 Th cells. Importantly, this suppression was less effective when TS1.Roquin(san/san) Th cells were used. Thus, high ICOS levels on effector T cells results in autoimmunity by augmenting the autoreactive B cell response and by dampening the effect of Treg cell suppression.

  4. Opposite effects of total lymphoid irradiation on T cell-dependent and T cell-independent antibody responses

    SciTech Connect

    Tanay, A.; Strober, S.

    1984-02-01

    The effect of total lymphoid irradiation (TLI) on the primary antibody response to the dinitrophenylated heterologous protein, keyhole limpet hemocyanin (DNP-KLH), in complete Freund's adjuvant (CFA), and to the trinitrophenylated polysaccharide antigen, Brucella abortus (TNP-BA), was studied in BALB/c mice. The antibody response to both antigens was diminished in comparison with nonirradiated mice when antigens were injected within 3 days after TLI. When the mice were immunized 30 days after completion of TLI the antibody response to DNP-KLH in CFA was still diminished, but the antibody response to TNP-BA was enhanced 5- to 10-fold as compared with that of control animals. The opposite effect of TLI on the two antibody responses was also observed in a syngeneic primary adoptive transfer system.

  5. Subset- and Antigen-Specific Effects of Treg on CD8+ T Cell Responses in Chronic HIV Infection.

    PubMed

    Nikolova, Maria; Wiedemann, Aurélie; Muhtarova, Maria; Achkova, Daniela; Lacabaratz, Christine; Lévy, Yves

    2016-11-01

    We, and others, have reported that in the HIV-negative settings, regulatory CD4+CD25highFoxP3+ T cells (Treg) exert differential effects on CD8 subsets, and maintain the memory / effector CD8+ T cells balance, at least in part through the PD-1/PD-L1 pathway. Here we investigated Treg-mediated effects on CD8 responses in chronic HIV infection. As compared to Treg from HIV negative controls (Treg/HIV-), we show that Treg from HIV infected patients (Treg/HIV+) did not significantly inhibit polyclonal autologous CD8+ T cell function indicating either a defect in the suppressive capacity of Treg/HIV+ or a lack of sensitivity of effector T cells in HIV infection. Results showed that Treg/HIV+ inhibited significantly the IFN-γ expression of autologous CD8+ T cells stimulated with recall CMV/EBV/Flu (CEF) antigens, but did not inhibit HIV-Gag-specific CD8+ T cells. In cross-over cultures, we show that Treg/HIV- inhibited significantly the differentiation of either CEF- or Gag-specific CD8+ T cells from HIV infected patients. The expression of PD-1 and PD-L1 was higher on Gag-specific CD8+ T cells as compared to CEF-specific CD8+ T cells, and the expression of these markers did not change significantly after Treg depletion or co-culture with Treg/HIV-, unlike on CEF-specific CD8+ T cells. In summary, we show a defect of Treg/HIV+ in modulating both the differentiation and the expression of PD-1/PD-L1 molecules on HIV-specific CD8 T cells. Our results strongly suggest that this particular defect of Treg might contribute to the exhaustion of HIV-specific T cell responses.

  6. Subset- and Antigen-Specific Effects of Treg on CD8+ T Cell Responses in Chronic HIV Infection

    PubMed Central

    Nikolova, Maria; Wiedemann, Aurélie; Achkova, Daniela

    2016-01-01

    We, and others, have reported that in the HIV-negative settings, regulatory CD4+CD25highFoxP3+ T cells (Treg) exert differential effects on CD8 subsets, and maintain the memory / effector CD8+ T cells balance, at least in part through the PD-1/PD-L1 pathway. Here we investigated Treg–mediated effects on CD8 responses in chronic HIV infection. As compared to Treg from HIV negative controls (Treg/HIV-), we show that Treg from HIV infected patients (Treg/HIV+) did not significantly inhibit polyclonal autologous CD8+ T cell function indicating either a defect in the suppressive capacity of Treg/HIV+ or a lack of sensitivity of effector T cells in HIV infection. Results showed that Treg/HIV+ inhibited significantly the IFN-γ expression of autologous CD8+ T cells stimulated with recall CMV/EBV/Flu (CEF) antigens, but did not inhibit HIV-Gag–specific CD8+ T cells. In cross-over cultures, we show that Treg/HIV- inhibited significantly the differentiation of either CEF- or Gag-specific CD8+ T cells from HIV infected patients. The expression of PD-1 and PD-L1 was higher on Gag-specific CD8+ T cells as compared to CEF-specific CD8+ T cells, and the expression of these markers did not change significantly after Treg depletion or co-culture with Treg/HIV-, unlike on CEF-specific CD8+ T cells. In summary, we show a defect of Treg/HIV+ in modulating both the differentiation and the expression of PD-1/PD-L1 molecules on HIV-specific CD8 T cells. Our results strongly suggest that this particular defect of Treg might contribute to the exhaustion of HIV-specific T cell responses. PMID:27829019

  7. Comprehensive mapping of antigen specific T cell responses in hepatitis C virus infected patients with or without spontaneous viral clearance

    PubMed Central

    Cui, Yuanyuan; Wang, Shasha; Yan, Hongqing; Li, Dongmei; Zhang, Yonghong; Tu, Zhengkun; Hao, Pei; Chen, Xinyue; Zhong, Jin; Niu, Junqi; Jin, Xia

    2017-01-01

    Elucidating protective immunity against HCV is important for the development of a preventative vaccine. We hypothesize that spontaneous resolution of acute HCV infection offers clue to protective immune responses, and that DAA therapy affects the quality and quantity of HCV-specific T cell responses. To test these hypotheses, we performed T cell epitope mapping in 111 HCV-infected individuals including 61 chronically HCV-1b (CHC-1b) infected, 24 chronically HCV-2a (CHC-2a) infected and 26 spontaneously recovered (SPR) patients with 376 overlapping peptides covering the entire HCV polyprotein. Selected T cell epitopes were then used to evaluate T cell responses in another 22 chronically HCV-1b infected patients on DAA therapy. Results showed that SPR had better HCV-specific T cell responses than CHC, as manifested by higher response rate, greater magnitude and broader epitope coverage. In addition, SPR recognized novel epitopes in Core, E1, E2, NS4B, NS5A regions that were not present in the CHC. Furthermore, during the first 24 weeks of DAA therapy, there was no functional immune reconstitution of HCV-specific T cells. These results indicate that T cell responses may be a correlate of protection. Therefore, effective preventative vaccines should elicit a robust T cell response. Although various DAA regimens efficiently cleared viruses from the blood of HCV-infected patients, there was no contemporaneous early T cell immune reconstitution, suggesting that early treatment is needed for preserving the functions of HCV-specific T cells. PMID:28170421

  8. Systematic identification of immunodominant CD4+ T cell responses to HpaA in Helicobacter pylori infected individuals

    PubMed Central

    Yang, Wuchen; Li, Bin; Sun, Heqiang; Wei, Shanshan; He, Yafei; Zhao, Zhuo; Yang, Shiming; Zou, Quanming; Chen, Weisan; Guo, Hong; Wu, Chao

    2016-01-01

    In mice, antigen-specific CD4+ T cell response is indispensible for the protective immunity against Helicobacter pylori (H. pylori). It has been demonstrated that neuraminyllactose-binding hemagglutinin (HpaA) immunization protected mice from H. pylori infection in a CD4+ T cell dependent manner. However, much remains unclear concerning the human CD4+ T cell responses to HpaA. We conducted a systematic study here to explore the immunodominant, HpaA-specific CD4+ T cell responses in H. pylori infected individuals. We found that HpaA-specific CD4+ T cell responses varied remarkably in their magnitude and had broad epitope-specificity. Importantly, the main responses focused on two regions: HpaA76-105 and HpaA130-159. The HLA-DRB1*0901 restricted HpaA142-159 specific CD4+ T cell response was the most immunodominant response at a population level. The immunodominant epitope HpaA142-159 was naturally presented and highly conserved. We also demonstrated that it was not the broad peptide specificity, but the strength of HpaA specific CD4+ T cell responses associated with gastric diseases potentially caused by H. pylori infection. Such investigation will aid development of novel vaccines against H. pylori infection. PMID:27509059

  9. The Role of Il-12 and Type I Interferon in Governing the Magnitude of CD8 T Cell Responses.

    PubMed

    Starbeck-Miller, Gabriel R; Harty, John T

    2015-01-01

    Antigen-specific CD8 T cells provide an important protective role in response to infection by viruses, intracellular bacteria, and parasites. Pathogen-specific CD8 T cells render this protection by undergoing robust expansion in numbers while gaining the ability to produce cytokines and cytolytic machinery. Creating optimal CD8 T cell responses to infection can be critical for raising sufficient armament to provide protection against invading intracellular pathogens. Although CD8 T cells have protective value, many vaccine strategies tend to focus on creating productive B cell antibody responses to promote immunological protection. Even though antibody responses can be highly protective, coupling optimal CD8 T cell responses with suboptimal B cell responses could provide higher orders of protection than either one on their own. Therefore, a deeper understanding of the pathways that ultimately guide the magnitude of CD8 T cell responses is required to explore this potential therapeutic benefit. The following chapter highlights our current understanding of how inflammatory cytokines regulate the magnitude of CD8 T cell responses.

  10. The Yin and Yang aspects of IL-27 in induction of cancer-specific T-cell responses and immunotherapy.

    PubMed

    Li, Ming-Song; Liu, Zhenzhen; Liu, Jin-Qing; Zhu, Xiaotong; Liu, Zhihao; Bai, Xue-Feng

    2015-01-01

    Accumulating evidences from animal studies have indicated that both endogenous and exogenous IL-27, an IL-12 family of cytokine, can increase antitumor T-cell activities and inhibit tumor growth. IL-27 can modulate Treg responses, and program effector T cells into a unique T-effector stem cell (TSEC) phenotype, which enhances T-cell survival in the tumor microenvironment. However, animal studies also suggest that IL-27 induces molecular pathways such as IL-10, PD-L1 and CD39, which may downregulate tumor-specific T-cell responses. In this review paper, we will discuss the Yin and Yang aspects of IL-27 in the induction of tumor-specific T-cell responses, and the potential impacts of these functions of IL-27 in the design of cancer immunotherapy.

  11. Polyfunctional cytokine production by central memory T cells from cattle in response to Mycobacterium bovis infection and BCG vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyfunctional T cells simultaneously produce IFN-gamma, IL-2 and TNF-alpha and play relevant roles in several chronic infections, including TB. Mycobacterium bovis infection of cattle elicits ex vivo polyfunctional T cell responses. Vaccine-elicited IFN-gamma Tcm (CD4 plus CD45RO plus CCR7 plus) re...

  12. The application of anti-Toso antibody enhances CD8(+) T cell responses in experimental malaria vaccination and disease.

    PubMed

    Lapke, Nina; Tartz, Susanne; Lee, Kyeong-Hee; Jacobs, Thomas

    2015-11-27

    Toso is a molecule highly expressed on B cells. It influences their survival and was identified as an IgM binding molecule. B cells and natural antibodies play a role in vaccination-induced CD8(+) T cell responses. We investigated the impact of an anti-Toso antibody on vaccination efficiency in a malaria vaccination model. In this model, CD8(+) T cells exert antiparasitic functions on infected hepatocytes in the liver stage of the disease. In vaccinated anti-Toso treated mice, more antigen-specific CD8(+) T cells were induced than in control mice and after infection with Plasmodium berghei ANKA (PbA) sporozoites, the liver parasite burden was lower. In B cell deficient mice, the anti-Toso antibody did not stimulate the CD8(+) T cell response, indicating that B cells were mediating this effect. Furthermore, we analyzed the influence of anti-Toso treatment on non-vaccinated mice in the PbA infection model, in which CD8(+) T cells cause brain pathology. Anti-Toso treatment increased cerebral pathology and the accumulation of CD8(+) T cells in the brain. Thus, anti-Toso treatment enhanced the CD8(+) T cell response against PbA in a vaccination and in an infection model. Our findings indicate that Toso may be a novel target to boost vaccine-induced CD8(+) T cell responses.

  13. Rapid and strong human CD8+ T cell responses to vaccination with peptide, IFA, and CpG oligodeoxynucleotide 7909.

    PubMed

    Speiser, Daniel E; Liénard, Danielle; Rufer, Nathalie; Rubio-Godoy, Verena; Rimoldi, Donata; Lejeune, Ferdy; Krieg, Arthur M; Cerottini, Jean-Charles; Romero, Pedro

    2005-03-01

    The induction of potent CD8+ T cell responses by vaccines to fight microbes or tumors remains a major challenge, as many candidates for human vaccines have proved to be poorly immunogenic. Deoxycytidyl-deoxyguanosin oligodeoxynucleotides (CpG ODNs) trigger Toll-like receptor 9, resulting in dendritic cell maturation that can enhance immunogenicity of peptide-based vaccines in mice. We tested whether a synthetic ODN, CpG 7909, could improve human tumor antigen-specific CD8+ T cell responses. Eight HLA-A2+ melanoma patients received 4 monthly vaccinations of low-dose CpG 7909 mixed with melanoma antigen A (Melan-A; identical to MART-1) analog peptide and incomplete Freund's adjuvant. All patients exhibited rapid and strong antigen-specific T cell responses: the frequency of Melan-A-specific T cells reached over 3% of circulating CD8+ T cells. This was one order of magnitude higher than the frequency seen in 8 control patients treated similarly but without CpG and 1-3 orders of magnitude higher than that seen in previous studies with synthetic vaccines. The enhanced T cell populations consisted primarily of effector memory cells, which in part secreted IFN- and expressed granzyme B and perforin ex vivo. In vitro, T cell clones recognized and killed melanoma cells in an antigen-specific manner. Thus, CpG 7909 is an efficient vaccine adjuvant that promotes strong antigen-specific CD8+ T cell responses in humans.

  14. Cytomegalovirus-specific T-cell responses and viral replication in kidney transplant recipients

    PubMed Central

    Egli, Adrian; Binet, Isabelle; Binggeli, Simone; Jäger, Clemens; Dumoulin, Alexis; Schaub, Stefan; Steiger, Juerg; Sester, Urban; Sester, Martina; Hirsch, Hans H

    2008-01-01

    Background Cytomegalovirus (CMV) seronegative recipients (R-) of kidney transplants (KT) from seropositive donors (D+) are at higher risk for CMV replication and ganciclovir(GCV)-resistance than CMV R(+). We hypothesized that low CMV-specific T-cell responses are associated with increased risk of CMV replication in R(+)-patients with D(+) or D(-) donors. Methods We prospectively evaluated 73 consecutive KT-patients [48 R(+), 25 D(+)R(-)] undergoing routine testing for CMV replication as part of a preemptive strategy. We compared CMV-specific interferon-γ (IFN-γ) responses of CD4+CD3+ lymphocytes in peripheral blood mononuclear cells (PBMC) using three different antigen preparation (CMV-lysate, pp72- and pp65-overlapping peptide pools) using intracellular cytokine staining and flow cytometry. Results Median CD4+ and CD8+T-cell responses to CMV-lysate, pp72- and pp65-overlapping peptide pools were lower in D(+)R(-) than in R(+)patients or in non-immunosuppressed donors. Comparing subpopulations we found that CMV-lysate favored CD4+- over CD8+-responses, whereas the reverse was observed for pp72, while pp65-CD4+- and -CD8+-responses were similar. Concurrent CMV replication in R(+)-patients was associated with significantly lower T-cell responses (pp65 median CD4+ 0.00% vs. 0.03%, p = 0.001; CD8+ 0.01% vs. 0.03%; p = 0.033). Receiver operated curve analysis associated CMV-pp65 CD4+ responses of > 0.03% in R(+)-patients with absence of concurrent (p = 0.003) and future CMV replication in the following 8 weeks (p = 0.036). GCV-resistant CMV replication occurred in 3 R(+)-patients (6.3%) with pp65- CD4+ frequencies < 0.03% (p = 0.041). Conclusion The data suggest that pp65-specific CD4+ T-cells might be useful to identify R(+)-patients at increased risk of CMV replication. Provided further corroborating evidence, CMV-pp65 CD4+ responses above 0.03% in PBMCs of KT patients under stable immunosuppression are associated with lower risk of concurrent and future CMV

  15. Trichloroethylene activates CD4+ T cells: potential role in an autoimmune response.

    PubMed

    Gilbert, K M; Griffin, J M; Pumford, N R

    1999-11-01

    Trichloroethylene is an industrial solvent and has become a major environmental contaminant. Autoimmune-prone MRL +/+ mice were treated for up to 22 weeks with trichloroethylene in the drinking water (0, 2.5, and 5.0 mg/mL) in order to study the immunoregulatory effects of this environmental toxicant. After only 4 weeks of treatment, trichloroethylene was shown to promote the expansion of CD4+ T cells that expressed a memory/activation phenotype (i.e., CD44hi CD45RBlo) and secreted high levels of IFN-gamma, but not IL-4. In addition, trichloroethylene treatment accelerated the development of an autoimmune response in the MRL +/+ mice as evidenced by an earlier appearance of antinuclear antibodies and increased levels of total IgG2a. MRL +/+ mice treated with trichloroethylene for 22 weeks also contained antibodies specific for trichloroethylene adducts, suggesting the activation of trichloroethylene-specific T cells. The results suggest that trichloroethylene can stimulate antigen nonspecific as well as specific T cells that are capable of promoting autoimmunity in genetically predisposed individuals.

  16. Regulatory T cells in the humoral response of protein deficient mice.

    PubMed

    Price, P; Turner, K J

    1979-01-01

    Cell suspensions from the spleen or thymus of mice fed normally or mice that were protein deficient were injected into mice from each dietary group and also syngeneic nudes. Antigen, polyvinyl pyrrolidone (PVP), was injected at the stage of cell transfer and the antibody titres of the recipient animals were compared with those of control animals given only antigen. The regime was repeated using cell suspensions from donor animals which had been primed with antigen. These experiments showed that spleen cells were suppressive only when transferred from deficient to normal mice. Thymocytes generally lacked suppressive effects, except when given to irradiated mice also injected with "normal" spleen cells. However, thymocytes from deficient mice were marginally enhancing in nude mice, deficient mice and older "normals". To explain these results, it is suggested that responses to PVP are determined by distinct "suppressor-inducing" and "suppressor" T cells which act via helper T cells. The latter probably affect B cells directly and largely influence IgG production. It also appears likely that the ratio of helper to suppressor (inducer and effector) T cells is increased by protein deficiency.

  17. Galectin-8 Ameliorates Murine Autoimmune Ocular Pathology and Promotes a Regulatory T Cell Response

    PubMed Central

    Sampson, James F.; Hasegawa, Eiichi; Mulki, Lama; Suryawanshi, Amol; Jiang, Shuhong; Chen, Wei-Sheng; Rabinovich, Gabriel A.; Connor, Kip M.; Panjwani, Noorjahan

    2015-01-01

    Galectins have emerged as potent immunoregulatory agents that control chronic inflammation through distinct mechanisms. Here, we report that treatment with Galectin-8 (Gal-8), a tandem-repeat member of the galectin family, reduces retinal pathology and prevents photoreceptor cell damage in a murine model of experimental autoimmune uveitis. Gal-8 treatment increased the number of regulatory T cells (Treg) in both the draining lymph node (dLN) and the inflamed retina. Moreover, a greater percentage of Treg cells in the dLN and retina of Gal-8 treated animals expressed the inhibitory coreceptor cytotoxic T lymphocyte antigen (CTLA)-4, the immunosuppressive cytokine IL-10, and the tissue-homing integrin CD103. Treg cells in the retina of Gal-8-treated mice were primarily inducible Treg cells that lack the expression of neuropilin-1. In addition, Gal-8 treatment blunted production of inflammatory cytokines by retinal T helper type (TH) 1 and TH17 cells. The effect of Gal-8 on T cell differentiation and/or function was specific for tissues undergoing an active immune response, as Gal-8 treatment had no effect on T cell populations in the spleen. Given the need for rational therapies for managing human uveitis, Gal-8 emerges as an attractive therapeutic candidate not only for treating retinal autoimmune diseases, but also for other TH1- and TH17-mediated inflammatory disorders. PMID:26126176

  18. Ipilimumab reshapes T cell memory subsets in melanoma patients with clinical response

    PubMed Central

    Felix, Joana; Lambert, Jérome; Roelens, Marie; Maubec, Eve; Guermouche, Hélène; Pages, Cécile; Sidina, Irina; Cordeiro, Debora J.; Maki, Guitta; Chasset, François; Porcher, Raphaël; Bagot, Martine; Caignard, Anne; Toubert, Antoine; Lebbé, Céleste; Moins-Teisserenc, Hélène

    2016-01-01

    ABSTRACT Purpose: Therapy targeting CTLA-4 immune checkpoint provides increased survival in patients with advanced melanoma. However, immunotherapy is frequently associated with delayed and heterogeneous clinical responses and it is important to identify prognostic immunological correlates of clinical endpoints. Experimental design: 77 patients with stage III/IV melanoma were treated with ipilimumab alone every 3 weeks, during 9 weeks. Blood samples were collected at the baseline and before each dose for in depth immune monitoring. Results: The median follow-up was 28 mo with a median survival of 7 mo. Survival and clinical benefit were significantly improved when absolute lymphocyte count at the baseline was above 1 × 109/L. Notably, ipilimumab had a global effect on memory T cells, with an early increase of central and effector subsets in patients with disease control. By contrast, percentages of stem cell memory T cells (TSCM) gradually decreased despite stable absolute counts and sustained proliferation, suggesting a process of differentiation. Higher proportions of eomes+ and Ki-67+ T cells were observed, with enhanced skin homing potential and induction of cytotoxic markers. Conclusion: These results suggest that CTLA-4 blockade is able to reshape the memory subset with the potential involvement of Eomes and memory subsets including TSCM. PMID:27622012

  19. Distinctive in vitro effects of T-cell growth cytokines on cytomegalovirus-stimulated T-cell responses of HIV-infected HAART recipients

    SciTech Connect

    Patterson, Julie; Jesser, Renee; Weinberg, Adriana

    2008-08-15

    Functional immune reconstitution is limited after HAART, maintaining the interest in adjunctive immune-modulators. We compared in vitro the effects of the {gamma}-chain T-cell growth cytokines IL-2, IL-4, IL-7 and IL-15 on cytomegalovirus-stimulated cell-mediated immunity. IL-2 and IL-15 increased cytomegalovirus-specific lymphocyte proliferation in HAART recipients, whereas IL-4 and IL-7 did not. The boosting effect of IL-2 and IL-15 on proliferation correlated with their ability to prevent late apoptosis. However, IL-2 increased the frequency of cells in early apoptosis, whereas IL-15 increased the frequency of fully viable cells. Both IL-2 and IL-15 increased cytomegalovirus-induced CD4{sup +} and CD8{sup +} T-cell proliferation and the synthesis of Th1 and pro-inflammatory cytokines and chemokines. However, only IL-2 increased the frequency of regulatory T cells and Th2 cytokine production, both of which have the potential to attenuate antiviral immune responses. Overall, compared to other {gamma}-chain cytokines, IL-15 had the most favorable profile for boosting antiviral cell-mediated immunity.

  20. Distinct T cell interactions with HLA class II tetramers characterize a spectrum of TCR affinities in the human antigen-specific T cell response.

    PubMed

    Reichstetter, S; Ettinger, R A; Liu, A W; Gebe, J A; Nepom, G T; Kwok, W W

    2000-12-15

    The polyclonal nature of T cells expanding in an ongoing immune response results in a range of disparate affinities and activation potential. Recently developed human class II tetramers provide a means to analyze this diversity by direct characterization of the trimolecular TCR-peptide-MHC interaction in live cells. Two HSV-2 VP16(369-379)-specific, DQA1*0102/DQB1*0602 (DQ0602)-restricted T cell clones were compared by means of T cell proliferation assay and HLA-DQ0602 tetramer staining. These two clones were obtained from the same subject, but show different TCR gene usage. Clone 48 was 10-fold more sensitive to VP16(369-379) peptide stimulation than clone 5 as assayed by proliferation assays, correlating with differences in MHC tetramer binding. Clone 48 gave positive staining with the DQ0602/VP16(369-379) tetramer at either 23 or 37 degrees C. Weak staining was also observed at 4 degrees C. Clone 5 showed weaker staining compared with clone 48 at 37 degrees C, and no staining was observed at 23 degrees C or on ice. Receptor internalization was not required for positive staining. Competitive binding indicates that the cell surface TCR of clone 48 has higher affinity for the DQ0602/VP16(369-379) complex than clone 5. The higher binding affinity of clone 48 for the peptide-MHC complex also correlates with a slower dissociation rate compared with clone 5.

  1. PARP-1/PARP-2 double deficiency in mouse T cells results in faulty immune responses and T lymphomas

    PubMed Central

    Navarro, Judith; Gozalbo-López, Beatriz; Méndez, Andrea C.; Dantzer, Françoise; Schreiber, Valérie; Martínez, Carlos; Arana, David M.; Farrés, Jordi; Revilla-Nuin, Beatriz; Bueno, María F.; Ampurdanés, Coral; Galindo-Campos, Miguel A.; Knobel, Philip A.; Segura-Bayona, Sandra; Martin-Caballero, Juan; Stracker, Travis H.; Aparicio, Pedro; Del Val, Margarita; Yélamos, José

    2017-01-01

    The maintenance of T-cell homeostasis must be tightly regulated. Here, we have identified a coordinated role of Poly(ADP-ribose) polymerase-1 (PARP-1) and PARP-2 in maintaining T-lymphocyte number and function. Mice bearing a T-cell specific deficiency of PARP-2 in a PARP-1-deficient background showed defective thymocyte maturation and diminished numbers of peripheral CD4+ and CD8+ T-cells. Meanwhile, peripheral T-cell number was not affected in single PARP-1 or PARP-2-deficient mice. T-cell lymphopenia was associated with dampened in vivo immune responses to synthetic T-dependent antigens and virus, increased DNA damage and T-cell death. Moreover, double-deficiency in PARP-1/PARP-2 in T-cells led to highly aggressive T-cell lymphomas with long latency. Our findings establish a coordinated role of PARP-1 and PARP-2 in T-cell homeostasis that might impact on the development of PARP-centred therapies. PMID:28181505

  2. PARP-1/PARP-2 double deficiency in mouse T cells results in faulty immune responses and T lymphomas.

    PubMed

    Navarro, Judith; Gozalbo-López, Beatriz; Méndez, Andrea C; Dantzer, Françoise; Schreiber, Valérie; Martínez, Carlos; Arana, David M; Farrés, Jordi; Revilla-Nuin, Beatriz; Bueno, María F; Ampurdanés, Coral; Galindo-Campos, Miguel A; Knobel, Philip A; Segura-Bayona, Sandra; Martin-Caballero, Juan; Stracker, Travis H; Aparicio, Pedro; Del Val, Margarita; Yélamos, José

    2017-02-09

    The maintenance of T-cell homeostasis must be tightly regulated. Here, we have identified a coordinated role of Poly(ADP-ribose) polymerase-1 (PARP-1) and PARP-2 in maintaining T-lymphocyte number and function. Mice bearing a T-cell specific deficiency of PARP-2 in a PARP-1-deficient background showed defective thymocyte maturation and diminished numbers of peripheral CD4(+) and CD8(+) T-cells. Meanwhile, peripheral T-cell number was not affected in single PARP-1 or PARP-2-deficient mice. T-cell lymphopenia was associated with dampened in vivo immune responses to synthetic T-dependent antigens and virus, increased DNA damage and T-cell death. Moreover, double-deficiency in PARP-1/PARP-2 in T-cells led to highly aggressive T-cell lymphomas with long latency. Our findings establish a coordinated role of PARP-1 and PARP-2 in T-cell homeostasis that might impact on the development of PARP-centred therapies.

  3. Human cord blood T-cell receptor alpha beta cell responses to protein antigens of Paracoccidioides brasiliensis yeast forms.

    PubMed Central

    Munk, M E; Kaufmann, S H

    1995-01-01

    Paracoccidioides brasiliensis causes a chronic granulomatous mycosis, prevalent in South America, and cell-mediated immunity represents the principal mode of protection against this fungal infection. We investigated the response of naive cord blood T cells to P. brasiliensis lysates. Our results show: (1) P. brasiliensis stimulates T-cell expansion, interleukin-2 (IL-2) production and differentiation into cytotoxic T cells; (2) T-cell stimulation depends on P. brasiliensis processing and major histocompatibility complex (MHC) class II expression; (3) the responsive T-cell population expresses alpha beta T-cell receptors (TCR) with different V beta gene products, CD4 and CD45RO; (4) the P. brasiliensis components involved in T-cell expansion primarily reside in a high molecular weight (100,000 MW) and a low molecular weight (< 1000 MW) protein fraction. These results indicate that protein antigens of P. brasiliensis stimulate cord blood CD4 alpha beta T cells, independent from in vivo presensitization, and thus question direct correlation of positive in vitro responses with protective immunity in vivo. PMID:7890308

  4. A human T cell clone that mediates the monocyte procoagulant response to specific sensitizing antigen.

    PubMed

    Schwartz, B S; Reitnauer, P J; Hank, J A; Sondel, P M

    1985-09-01

    A panel of human purified protein derivative of the tubercle bacillus (PPD)-reactive T cell clones was derived by cloning out of soft agar followed by cultivation on inactivated feeder cells in the presence of interleukin-2. 1 of 4 clones tested was able to mediate an increase in monocyte procoagulant activity (PCA) in response to PPD. All four clones had identical surface marker phenotypes (T4+, T8-) and proliferated in response to antigen. The reactive T cell clone possessed no PCA of its own, but upon being presented with PPD was able to instruct monocytes to increase their expression of PCA. Antigen presentation could be performed only by autologous monocytes; allogeneic monocytes from donors unrelated to the donor of the reactive clone could not present antigen to cells of the clone in a way that would initiate the procoagulant response. Cells of the reactive clone did not mediate increased monocyte PCA in response to Candida, even though peripheral blood mononuclear cells from the donor demonstrated increased PCA to both Candida and PPD. Thus, the PCA response to specific antigen can be mediated by a single clone of cells that shows specificity in the recognition of both antigen and antigen presenting cell.

  5. Definition of the viral targets of protective HIV-1-specific T cell responses

    PubMed Central

    2011-01-01

    Background The efficacy of the CTL component of a future HIV-1 vaccine will depend on the induction of responses with the most potent antiviral activity and broad HLA class I restriction. However, current HIV vaccine designs are largely based on viral sequence alignments only, not incorporating experimental data on T cell function and specificity. Methods Here, 950 untreated HIV-1 clade B or -C infected individuals were tested for responses to sets of 410 overlapping peptides (OLP) spanning the entire HIV-1 proteome. For each OLP, a "protective ratio" (PR) was calculated as the ratio of median viral loads (VL) between OLP non-responders and responders. Results For both clades, there was a negative relationship between the PR and the entropy of the OLP sequence. There was also a significant additive effect of multiple responses to beneficial OLP. Responses to beneficial OLP were of significantly higher functional avidity than responses to non-beneficial OLP. They also had superior in-vitro antiviral activities and, importantly, were at least as predictive of individuals' viral loads than their HLA class I genotypes. Conclusions The data thus identify immunogen sequence candidates for HIV and provide an approach for T cell immunogen design applicable to other viral infections. PMID:22152067

  6. In vitro activation of hTERT-specific T cell responses in lung cancer patients following chemotherapy

    PubMed Central

    Staudinger, Matthias; Woester, Katrin; Wellnitz, Dominique; Boettcher, Sebastian; Gramatzki, Martin; Kneba, Michael

    2013-01-01

    Objective The aim of this study was to examine chemotherapy concomitant in vitro activation of human telomerase reverse transcriptase (hTERT)-specific T cell responses in peripheral blood mononuclear cell (PBMC) samples of patients with advanced non-small cell lung cancer (NSCLC). Methods PBMCs depleted of regulatory T cells were stimulated by peptide loaded dendritic cells (DC) matured either by application of cytokines (cDC) or a Toll-like receptor 7/8-agonist combined with a soluble CD40-ligand (ligDC). The hTERT peptide-specific T cell responses were assessed using flow cytometry for intracellular interferon-γ (IFN-γ). Results After cDC activation, T cells producing IFN-γ in response to hTERT were found in PBMC samples of 4 patients. In 2 of these patients the hTERT-specific T cell responses were further increased after ligDC application. However, PBMC of 3 other patients showed little or no induction of hTERT-specific T cell responses as a result of the methods applied during this study. Conclusions These results indicate, that concomitant to chemotherapy hTERT-specific T cell responses can be activated in PBMC of NSCLC patients in vitro. This activation can be further increased by ligDC though the number of responding patients is still limited. PMID:23825754

  7. FoxP3+ regulatory T cells are not important for rotavirus clearance or the early antibody response to rotavirus.

    PubMed

    Miller, Amber D; Blutt, Sarah E; Conner, Margaret E

    2014-01-01

    Regulatory T cells produce TGF-β that contributes to IgA induction by intestinal commensal bacteria but their importance in IgA responses to pathogens has not been determined. Immunity against the enteropathogen, rotavirus, is dependent on intestinal IgA, but whether FoxP3(+) regulatory T cells contribute to this IgA is unknown. Infection with rotavirus increased the numbers of intestinal FoxP3(+) regulatory T cells. Depletion of FoxP3(+) regulatory T cells altered leukocyte activation but did not significantly alter rotavirus clearance or specific antibody levels. These data suggest FoxP3(+) regulatory T cells are not critical for the early antibody response to rotavirus infection.

  8. Tumor-derived γδ regulatory T cells suppress innate and adaptive immunity through the induction of immunosenescence.

    PubMed

    Ye, Jian; Ma, Chunling; Hsueh, Eddy C; Eickhoff, Christopher S; Zhang, Yanping; Varvares, Mark A; Hoft, Daniel F; Peng, Guangyong

    2013-03-01

    Fundamentally understanding the suppressive mechanisms used by different subsets of tumor-infiltrating regulatory T (Treg) cells is critical for the development of effective strategies for antitumor immunotherapy. γδ Treg cells have recently been identified in human diseases including cancer. However, the suppressive mechanisms and functional regulations of this new subset of unconventional Treg cells are largely unknown. In the current studies, we explored the suppressive mechanism(s) used by breast tumor-derived γδ Treg cells on innate and adaptive immunity. We found that γδ Treg cells induced immunosenescence in the targeted naive and effector T cells, as well as dendritic cells (DCs). Furthermore, senescent T cells and DCs induced by γδ Treg cells had altered phenotypes and impaired functions and developed potent suppressive activities, further amplifying the immunosuppression mediated by γδ Treg cells. In addition, we demonstrated that manipulation of TLR8 signaling in γδ Treg cells can block γδ Treg-induced conversion of T cells and DCs into senescent cells in vitro and in vivo. Our studies identify the novel suppressive mechanism mediated by tumor-derived γδ Treg cells on innate and adaptive immunity, which should be critical for the development of strong and innovative approaches to reverse the tumor-suppressive microenvironment and improve effects of immunotherapy.

  9. Responses of Bovine WC1+ γδ T Cells to Protein and Nonprotein Antigens of Mycobacterium bovis

    PubMed Central

    Welsh, Michael D.; Kennedy, Hilary E.; Smyth, Allister J.; Girvin, R. Martyn; Andersen, Peter; Pollock, John M.

    2002-01-01

    WC1+ γδ T cells of Mycobacterium bovis-infected cattle are highly responsive to M. bovis sonic extract (MBSE). In mycobacterial infections of other species, γδ T cells have been shown to respond to protein and nonprotein antigens, but the bovine WC1+ γδ T-cell antigenic targets within MBSE require further definition in terms of the dominance of protein versus nonprotein components. The present study sought to characterize the WC1+ γδ T-cell antigenic targets, together with the role of interleukin-2 (IL-2), in the context of M. bovis infection. This was achieved by testing crude and defined antigens to assess protein versus nonprotein recognition by WC1+ γδ T cells in comparison with CD4+ αβ T cells. Both cell types proliferated strongly in response to MBSE, with CD4+ T cells being the major producers of gamma interferon (IFN-γ). However, enzymatic digestion of the protein in MBSE removed its ability to stimulate CD4+ T-cell responses, whereas some WC1+ γδ T-cell proliferation remained. The most antigenic protein inducing proliferation and IFN-γ secretion in WC1+ γδ T-cell cultures was found to be ESAT-6, which is a potential novel diagnostic reagent and vaccine candidate. In addition, WC1+ γδ T-cell proliferation was observed in response to stimulation with prenyl pyrophosphate antigens (isopentenyl pyrophosphate and monomethyl phosphate). High levels of cellular activation (CD25 expression) resulted from MBSE stimulation of WC1+ γδ T cells from infected animals. A similar degree of activation was induced by IL-2 alone, but for WC1+ γδ T-cell division IL-2 was found to act only as a costimulatory signal, enhancing antigen-driven responses. Overall, the data indicate that protein antigens are important stimulators of WC1+ γδ T-cell proliferation and IFN-γ secretion in M. bovis infection, with nonprotein antigens inducing significant proliferation. These findings have important implications for diagnostic and vaccine development. PMID

  10. A role for granulocyte-macrophage colony-stimulating factor in the regulation of CD8{sup +} T cell responses to rabies virus

    SciTech Connect

    Wanjalla, Celestine N.; Goldstein, Elizabeth F.; Wirblich, Christoph; Schnell, Matthias J.

    2012-05-10

    Inflammatory cytokines have a significant role in altering the innate and adaptive arms of immune responses. Here, we analyzed the effect of GM-CSF on a RABV-vaccine vector co-expressing HIV-1 Gag. To this end, we immunized mice with RABV expressing HIV-1 Gag and GM-CSF and analyzed the primary and recall CD8{sup +} T cell responses. We observed a statistically significant increase in antigen presenting cells (APCs) in the spleen and draining lymph nodes in response to GM-CSF. Despite the increase in APCs, the primary and memory anti HIV-1 CD8{sup +} T cell response was significantly lower. This was partly likely due to lower levels of proliferation in the spleen. Animals treated with GM-CSF neutralizing antibodies restored the CD8{sup +} T cell response. These data define a role of GM-CSF expression, in the regulation of the CD8{sup +} T cell immune responses against RABV and has implications in the use of GM-CSF as a molecular adjuvant in vaccine development.

  11. Antibody and T Cell Responses to Fusobacterium nucleatum and Treponema denticola in Health and Chronic Periodontitis

    PubMed Central

    Shin, Jieun; Kho, Sang-A; Choi, Yun S.; Kim, Yong C.; Rhyu, In-Chul; Choi, Youngnim

    2013-01-01

    The characteristics of the T cell response to the members of oral flora are poorly understood. We characterized the antibody and T cell responses to FadA and Td92, adhesins from Fusobacterium nucleatum, an oral commensal, and Treponema denticola, a periodontal pathogen, respectively. Peripheral blood and saliva were obtained from healthy individuals and patients with untreated chronic periodontitis (CP, n = 11 paris) and after successful treatment of the disease (n = 9). The levels of antigen-specific antibody were measured by ELISA. In plasma, IgG1 was the most abundant isotype of Ab for both Ags, followed by IgA and then IgG4. The levels of FadA-specific salivary IgA (sIgA) were higher than Td92-specific sIgA and the FadA-specific IgA levels observed in plasma. However, the periodontal health status of the individuals did not affect the levels of FadA- or Td92-specific antibody. Even healthy individuals contained FadA- and Td92-specific CD4+ T cells, as determined by the detection of intracytoplasmic CD154 after short-term in vitro stimulation of peripheral blood mononuclear cells (PBMCs) with the antigens. Patients with CP tended to possess increased numbers of FadA- and Td92-specific CD4+ T cells but reduced numbers of Td92-specific Foxp3+CD4+ Tregs than the healthy subjects. Both FadA and Td92 induced the production of IFNγ and IL-10 but inhibited the secretion of IL-4 by PBMCs. In conclusion, F. nucleatum induced Th3 (sIgA)- and Th1 (IFNγ and IgG1)-dominant immune responses, whereas T. denticola induced a Th1 (IFNγ and IgG1)-dominant response. This IFNγ-dominant cytokine response was impaired in CP patients, and the Td92-induced IFNγ levels were negatively associated with periodontal destruction in patients. These findings may provide new insights into the homeostatic interaction between the immune system and oral bacteria and the pathogenesis of periodontitis. PMID:23335969

  12. Priming of transcriptional memory responses via the chromatin accessibility landscape in T cells

    PubMed Central

    Tu, Wen Juan; Hardy, Kristine; Sutton, Christopher R.; McCuaig, Robert; Li, Jasmine; Dunn, Jenny; Tan, Abel; Brezar, Vedran; Morris, Melanie; Denyer, Gareth; Lee, Sau Kuen; Turner, Stephen J.; Seddiki, Nabila; Smith, Corey; Khanna, Rajiv; Rao, Sudha

    2017-01-01

    Memory T cells exhibit transcriptional memory and “remember” their previous pathogenic encounter to increase transcription on re-infection. However, how this transcriptional priming response is regulated is unknown. Here we performed global FAIRE-seq profiling of chromatin accessibility in a human T cell transcriptional memory model. Primary activation induced persistent accessibility changes, and secondary activation induced secondary-specific opening of previously less accessible regions associated with enhanced expression of memory-responsive genes. Increased accessibility occurred largely in distal regulatory regions and was associated with increased histone acetylation and relative H3.3 deposition. The enhanced re-stimulation response was linked to the strength of initial PKC-induced signalling, and PKC-sensitive increases in accessibility upon initial stimulation showed higher accessibility on re-stimulation. While accessibility maintenance was associated with ETS-1, accessibility at re-stimulation-specific regions was linked to NFAT, especially in combination with ETS-1, EGR, GATA, NFκB, and NR4A. Furthermore, NFATC1 was directly regulated by ETS-1 at an enhancer region. In contrast to the factors that increased accessibility, signalling from bHLH and ZEB family members enhanced decreased accessibility upon re-stimulation. Interplay between distal regulatory elements, accessibility, and the combined action of sequence-specific transcription factors allows transcriptional memory-responsive genes to “remember” their initial environmental encounter. PMID:28317936

  13. Priming of transcriptional memory responses via the chromatin accessibility landscape in T cells.

    PubMed

    Tu, Wen Juan; Hardy, Kristine; Sutton, Christopher R; McCuaig, Robert; Li, Jasmine; Dunn, Jenny; Tan, Abel; Brezar, Vedran; Morris, Melanie; Denyer, Gareth; Lee, Sau Kuen; Turner, Stephen J; Seddiki, Nabila; Smith, Corey; Khanna, Rajiv; Rao, Sudha

    2017-03-20

    Memory T cells exhibit transcriptional memory and "remember" their previous pathogenic encounter to increase transcription on re-infection. However, how this transcriptional priming response is regulated is unknown. Here we performed global FAIRE-seq profiling of chromatin accessibility in a human T cell transcriptional memory model. Primary activation induced persistent accessibility changes, and secondary activation induced secondary-specific opening of previously less accessible regions associated with enhanced expression of memory-responsive genes. Increased accessibility occurred largely in distal regulatory regions and was associated with increased histone acetylation and relative H3.3 deposition. The enhanced re-stimulation response was linked to the strength of initial PKC-induced signalling, and PKC-sensitive increases in accessibility upon initial stimulation showed higher accessibility on re-stimulation. While accessibility maintenance was associated with ETS-1, accessibility at re-stimulation-specific regions was linked to NFAT, especially in combination with ETS-1, EGR, GATA, NFκB, and NR4A. Furthermore, NFATC1 was directly regulated by ETS-1 at an enhancer region. In contrast to the factors that increased accessibility, signalling from bHLH and ZEB family members enhanced decreased accessibility upon re-stimulation. Interplay between distal regulatory elements, accessibility, and the combined action of sequence-specific transcription factors allows transcriptional memory-responsive genes to "remember" their initial environmental encounter.

  14. Inhibition of in vitro and in vivo T cell responses by recombinant human Tim-1 extracellular domain proteins.

    PubMed

    Mesri, Mehdi; Smithson, Glennda; Ghatpande, Ashwini; Chapoval, Andrei; Shenoy, Suresh; Boldog, Ferenc; Hackett, Craig; Pena, Carol E; Burgess, Catherine; Bendele, Alison; Shimkets, Richard A; Starling, Gary C

    2006-03-01

    Members of the T cell, Ig domain and mucin domain (Tim) family of proteins have recently been implicated in the control of T cell-mediated immune responses. Tim-1 (HUGO designation HAVCR1) polymorphisms have been linked to the regulation of atopy in mice and humans, suggestive of a role in immune regulation. Tim-1 is expressed upon activation of T cells. In concert with the increased expression of Tim-1, a binding partner for the extracellular domain of Tim-1 (eTim-1) was induced on activated T cells, and mRNA expression data was consistent with the binding partner being Tim-4. We found that co-immobilized recombinant eTim-1 was able to inhibit T cell activation mediated by CD3 + CD28 mAb. eTim-1 mediated its inhibitory effects on proliferation by arresting cell cycle at G(0)/G(1) phase through regulation of cell cycle proteins. In vivo, administration of eTim-1 proteins led to a decrease in both ear (contact hypersensitivity to oxazolone) and joint (methylated BSA antigen-induced arthritis) swelling. The inhibitory activity of eTim-1 in the T(h)1-dependent models was evidence that eTim-1 is able to modulate T cell responses. Manipulation of the Tim-1 interaction with its binding partner on T cells may therefore provide a novel target for therapeutic intervention in T cell-mediated diseases.

  15. Dendritic Cell Targeting Effectively Boosts T Cell Responses Elicited by an HIV Multiepitope DNA Vaccine.

    PubMed

    Apostólico, Juliana de Souza; Lunardelli, Victória Alves Santos; Yamamoto, Marcio Massao; Souza, Higo Fernando Santos; Cunha-Neto, Edecio; Boscardin, Silvia Beatriz; Rosa, Daniela Santoro

    2017-01-01

    Despite several efforts in the last decades, an efficacious HIV-1 vaccine is still not available. Different approaches have been evaluated, such as recombinant proteins, viral vectors, DNA vaccines, and, most recently, dendritic cell (DC) targeting. This strategy is based on DC features that place them as central for induction of immunity. Targeting is accomplished by the use of chimeric monoclonal antibodies directed to DC surface receptors fused to the antigen of interest. In this work, we targeted eight promiscuous HIV-derived CD4(+) T cell epitopes (HIVBr8) to the DEC205(+) DCs by fusing the multiepitope immunogen to the heavy chain of αDEC205 (αDECHIVBr8), in the presence of the TLR3 agonist poly (I:C). In addition, we tested a DNA vaccine encoding the same epitopes using homologous or heterologous prime-boost regimens. Our results showed that mice immunized with αDECHIVBr8 presented higher CD4(+) and CD8(+) T cell responses when compared to mice that received the DNA vaccine (pVAXHIVBr8). In addition, pVAXHIVBr8 priming followed by αDECHIVBr8 boosting induced higher polyfunctional proliferative and cytokine-producing T cell responses to HIV-1 peptides than homologous DNA immunization or heterologous αDEC prime/DNA boost. Based on these results, we conclude that homologous prime-boost and heterologous boosting immunization strategies targeting CD4(+) epitopes to DCs are effective to improve HIV-specific cellular immune responses when compared to standalone DNA immunization. Moreover, our results indicate that antigen targeting to DC is an efficient strategy to boost immunity against a multiepitope immunogen, especially in the context of DNA vaccination.

  16. Dendritic Cell Targeting Effectively Boosts T Cell Responses Elicited by an HIV Multiepitope DNA Vaccine

    PubMed Central

    Apostólico, Juliana de Souza; Lunardelli, Victória Alves Santos; Yamamoto, Marcio Massao; Souza, Higo Fernando Santos; Cunha-Neto, Edecio; Boscardin, Silvia Beatriz; Rosa, Daniela Santoro

    2017-01-01

    Despite several efforts in the last decades, an efficacious HIV-1 vaccine is still not available. Different approaches have been evaluated, such as recombinant proteins, viral vectors, DNA vaccines, and, most recently, dendritic cell (DC) targeting. This strategy is based on DC features that place them as central for induction of immunity. Targeting is accomplished by the use of chimeric monoclonal antibodies directed to DC surface receptors fused to the antigen of interest. In this work, we targeted eight promiscuous HIV-derived CD4+ T cell epitopes (HIVBr8) to the DEC205+ DCs by fusing the multiepitope immunogen to the heavy chain of αDEC205 (αDECHIVBr8), in the presence of the TLR3 agonist poly (I:C). In addition, we tested a DNA vaccine encoding the same epitopes using homologous or heterologous prime-boost regimens. Our results showed that mice immunized with αDECHIVBr8 presented higher CD4+ and CD8+ T cell responses when compared to mice that received the DNA vaccine (pVAXHIVBr8). In addition, pVAXHIVBr8 priming followed by αDECHIVBr8 boosting induced higher polyfunctional proliferative and cytokine-producing T cell responses to HIV-1 peptides than homologous DNA immunization or heterologous αDEC prime/DNA boost. Based on these results, we conclude that homologous prime-boost and heterologous boosting immunization strategies targeting CD4+ epitopes to DCs are effective to improve HIV-specific cellular immune responses when compared to standalone DNA immunization. Moreover, our results indicate that antigen targeting to DC is an efficient strategy to boost immunity against a multiepitope immunogen, especially in the context of DNA vaccination. PMID:28223987

  17. ME-10TUMOR MICROENVIRONMENT INFILTRATING MYELOID DERIVED SUPPRESSOR CELLS INHIBIT ANTI-TUMOR T CELL RESPONSES

    PubMed Central

    Kamran, Neha; Ayala, Mariela; Li, Youping; Assi, Hikmat; Candolfi, Marianela; Dzaman, Marta; Lowenstein, Pedro; Castro, Maria

    2014-01-01

    MDSCs represent a population of immature myeloid cells at various stages of differentiation that inhibit anti-tumor T cell-mediated responses. We demonstrate the accumulation of MDSCs in GL26 induced glioma and B16 melanoma bearing mice. Absolute numbers of Ly-6G+ (Gr-1high) MDSCs showed a 200 fold increase within the tumor microenvironment (TME) 28 days post-tumor implantation. The numbers of Ly-6C+ (Gr-1low) MDSCs also showed a similar trend within the TME. While this massive influx of MDSCs was noted within intracranial tumors, MDSC levels did not increase in the dLNs, spleen or bone marrow (BM) of intracranial tumor bearing mice. MDSCs numbers were significantly elevated in the blood of GL26 intracranial tumor bearing mice at 28 days. Mice bearing B16 tumors in the flank showed a ∼5 fold increased influx of Ly-6G+ MDSCs while the Ly6C+ MDSCs increased marginally by 1.1 fold within the tumor mass. Levels of circulating MDSCs also increased by ∼10 fold, while the levels of splenic MDSCs did not change. While both Ly-6G+ and Ly6C+ MDSCs isolated from the brain TME of GL26 intracranial tumor bearing mice inhibited antigen-specific T cell proliferation, Ly6C+ MDSC were found to be more efficient. Ly6G+ or Ly6C+ MDSCs from the bone marrow of intracranial tumor bearing mice failed to suppress antigen-specific T cell proliferation. Splenic and bone marrow MDSCs from naïve mice also did not inhibit antigen-specific T cell proliferation suggesting that TME derived factors may activate MDSCs to exert their immune-suppressive properties. Microarray analysis of glioma cell lines showed elevated levels of CXCL1 mRNA and splenic MDSCs from GL26 tumor mice showed upregulation of the CXCR2 mRNA. Preliminary experiments indicate that CXCR2 signaling mediates MDSC chemotaxis. Overall, our data suggests that strategies that inhibit MDSC recruitment to the TME and/or block their activity could enhance the T cell mediated tumor clearance.

  18. T cell activation responses are differentially regulated during clinorotation and in spaceflight

    NASA Technical Reports Server (NTRS)

    Hashemi, B. B.; Penkala, J. E.; Vens, C.; Huls, H.; Cubbage, M.; Sams, C. F.

    1999-01-01

    Studies of T lymphocyte activation with mitogenic lectins during spaceflight have shown a dramatic inhibition of activation as measured by DNA synthesis at 72 h, but the mechanism of this inhibition is unknown. We have investigated the progression of cellular events during the first 24 h of activation using both spaceflight microgravity culture and a ground-based model system that relies on the low shear culture environment of a rotating clinostat (clinorotation). Stimulation of human peripheral blood mononuclear cells (PBMCs) with soluble anti-CD3 (Leu4) in clinorotation and in microgravity culture shows a dramatic reduction in surface expression of the receptor for IL-2 (CD25) and CD69. An absence of bulk RNA synthesis in clinorotation indicates that stimulation with soluble Leu4 does not induce transition of T cells from G0 to the G1 stage of the cell cycle. However, internalization of the TCR by T cells and normal levels of IL-1 synthesis by monocytes indicate that intercellular interactions that are required for activation occur during clinorotation. Complementation of TCR-mediated signaling by phorbol ester restores the ability of PBMCs to express CD25 in clinorotation, indicating that a PKC-associated pathway may be compromised under these conditions. Bypassing the TCR by direct activation of intracellular pathways with a combination of phorbol ester and calcium ionophore in clinorotation resulted in full expression of CD25; however, only partial expression of CD25 occurred in microgravity culture. Though stimulation of purified T cells with Bead-Leu4 in microgravity culture resulted in the engagement and internalization of the TCR, the cells still failed to express CD25. When T cells were stimulated with Bead-Leu4 in microgravity culture, they were able to partially express CD69, a receptor that is constitutively stored in intracellular pools and can be expressed in the absence of new gene expression. Our results suggest that the inhibition of T cell

  19. 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.

  20. Systematic identification of immunodominant CD8+ T-cell responses to influenza A virus in HLA-A2 individuals

    PubMed Central

    Wu, Chao; Zanker, Damien; Valkenburg, Sophie; Kedzierska, Katherine; Zou, Quan Ming; Doherty, Peter C.; Chen, Weisan

    2011-01-01

    Immunodominant T-cell responses are important for virus clearance. However, the identification of immunodominant T-cell peptide + HLA glycoprotein epitopes has been hindered by the extent of HLA polymorphism and the limitations of predictive algorithms. A simple, systematic approach has been used here to screen for immunodominant CD8+ T-cell specificities. The analysis targeted healthy HLA-A2+ donors to allow comparison with responses to the well-studied influenza matrix protein 1 epitope. Although influenza matrix protein 1 was consistently detected in all individual samples in our study, the response to this epitope was only immunodominant in three of eight, whereas for the other five, prominent CD8+ T-cell responses tended to focus on various peptides from the influenza nucleoprotein that were not presented by HLA-A2. Importantly, with the four immunodominant T-cell epitopes identified here, only one would have been detected by the current prediction programs. The other three peptides would have been either considered too long or classified as not containing typical HLA binding motifs. Our data stress the importance of systematic analysis for discovering HLA-dependent, immunodominant CD8+ T-cell epitopes derived from viruses and tumors. Focusing on HLA-A2 and predictive algorithms may be too limiting as we seek to develop targeted immunotherapy and vaccine strategies that depend on T cell-mediated immunity. PMID:21562214

  1. Transient Treg-cell depletion in adult mice results in persistent self-reactive CD4(+) T-cell responses.

    PubMed

    Nyström, Sofia N; Bourges, Dorothée; Garry, Sarah; Ross, Ellen M; van Driel, Ian R; Gleeson, Paul A

    2014-12-01

    Depletion of Foxp3(+) CD4(+) regulatory T cells (Treg) in adults results in chronic inflammation and autoimmune disease. However, the impact of transient Treg-cell depletion on self-reactive responses is poorly defined. Here, we studied the effect of transient depletion of Treg cells on CD4(+) T-cell responses to endogenous self-antigens. Short-term ablation of Treg cells in mice resulted in rapid activation of CD4(+) T cells, increased percentage of IFN-γ(+) and Th17 cells in lymphoid organs, and development of autoimmune gastritis. To track self-reactive responses, we analyzed the activation of naïve gastric-specific CD4(+) T cells. There was a dramatic increase in proliferation and acquisition of effector function of gastric-specific T cells in the stomach draining LNs of Treg-cell-depleted mice, compared with untreated mice, either during Treg-cell depletion or after Treg-cell reconstitution. Moreover, the hyperproliferation of gastric-specific T cells in the Treg-cell-ablated mice was predominantly antigen-dependent. Transient depletion of Treg cells resulted in a shift in the ratio of peripheral:thymic Treg cells in the reemerged Treg-cell population, indicating an altered composition of Treg cells. These findings indicate that transient Treg-cell depletion results in ongoing antigen-driven self-reactive T-cell responses and emphasize the continual requirement for an intact Treg-cell population.

  2. T cell immunity using transgenic B lymphocytes

    NASA Astrophysics Data System (ADS)

    Gerloni, Mara; Rizzi, Marta; Castiglioni, Paola; Zanetti, Maurizio

    2004-03-01

    Adaptive immunity exists in all vertebrates and plays a defense role against microbial pathogens and tumors. T cell responses begin when precursor T cells recognize antigen on specialized antigen-presenting cells and differentiate into effector cells. Currently, dendritic cells are considered the only cells capable of stimulating T lymphocytes. Here, we show that mature naïve B lymphocytes can be genetically programmed by using nonviral DNA and turned into powerful antigen-presenting cells with a dual capacity of synthesis and presentation of antigen to T cells in vivo. A single i.v. injection of transgenic lymphocytes activates T cell responses reproducibly and specifically even at very low cell doses (102). We also demonstrate that T cell priming can occur in the absence of dendritic cells and results in immunological memory with protective effector functions. These findings disclose aspects in the regulation of adaptive immunity and indicate possibilities for vaccination against viruses and cancer in humans.

  3. Cutting edge: monovalency of CD28 maintains the antigen dependence of T cell costimulatory responses.

    PubMed

    Dennehy, Kevin M; Elias, Fernando; Zeder-Lutz, Gabrielle; Ding, Xin; Altschuh, Danièle; Lühder, Fred; Hünig, Thomas

    2006-05-15

    CD28 and CTLA-4 are the major costimulatory receptors on naive T cells. But it is not clear why CD28 is monovalent whereas CTLA-4 is bivalent for their shared ligands CD80/86. We generated bivalent CD28 constructs by fusing the extracellular domains of CTLA-4 or CD80 with the intracellular domains of CD28. Bivalent or monovalent CD28 constructs were ligated with recombinant ligands with or without TCR coligation. Monovalent CD28 ligation did not induce responses unless the TCR was coligated. By contrast, bivalent CD28 ligation induced responses in the absence of TCR engagement. To extend these findings to primary cells, we used novel superagonistic and conventional CD28 Abs. Superagonistic Ab D665, but not conventional Ab E18, predominantly ligates CD28 bivalently at low CD28/Ab ratios and induces Ag-independent T cell proliferation. Monovalency of CD28 for its natural ligands is thus essential to provide costimulation without inducing responses in the absence of TCR engagement.

  4. CXCR3+ Regulatory T Cells Control TH1 Responses in Crescentic GN.

    PubMed

    Paust, Hans-Joachim; Riedel, Jan-Hendrik; Krebs, Christian F; Turner, Jan-Eric; Brix, Silke R; Krohn, Sonja; Velden, Joachim; Wiech, Thorsten; Kaffke, Anna; Peters, Anett; Bennstein, Sabrina B; Kapffer, Sonja; Meyer-Schwesinger, Catherine; Wegscheid, Claudia; Tiegs, Gisa; Thaiss, Friedrich; Mittrücker, Hans-Willi; Steinmetz, Oliver M; Stahl, Rolf A K; Panzer, Ulf

    2016-07-01

    Chemokines and chemokine receptors are implicated in regulatory T cell (Treg) trafficking to sites of inflammation and suppression of excessive immune responses in inflammatory and autoimmune diseases; however, the specific requirements for Treg migration into the inflamed organs and the positioning of these cells within the tissue are incompletely understood. Here, we report that Tregs expressing the TH1-associated chemokine receptor CXCR3 are enriched in the kidneys of patients with ANCA-associated crescentic GN and colocalize with CXCR3(+) effector T cells. To investigate the functional role of CXCR3(+) Tregs, we generated mice that lack CXCR3 in Tregs specifically (Foxp3(eGFP-Cre) × Cxcr3(fl/fl)) and induced experimental crescentic GN. Treg-specific deletion of CXCR3 resulted in reduced Treg recruitment to the kidney and an overwhelming TH1 immune response, with an aggravated course of the nephritis that was reversible on anti-IFNγ treatment. Together, these findings show that a subset of Tregs expresses CXCR3 and thereby, acquires trafficking properties of pathogenic CXCR3(+) TH1 cells, allowing Treg localization and control of excessive TH1 responses at sites of inflammation.

  5. Epigenetic and transcriptional regulation of γδ T cell differentiation: Programming cells for responses in time and space.

    PubMed

    Schmolka, Nina; Wencker, Mélanie; Hayday, Adrian C; Silva-Santos, Bruno

    2015-02-01

    γδ T cells are major providers of the pro-inflammatory cytokines interferon-γ (IFNγ) and interleukin-17 (IL-17) in protective or pathogenic immune responses. Notably, murine γδ T cells commit to either IFNγ or IL-17 production during development in the thymus, before any subsequent activation in the periphery. Here we discuss the molecular networks that underlie thymic γδ T cell differentiation, as well as the mechanisms that sustain or modify their functional properties in the periphery. We concentrate on recent findings on lymphoid and tissue-resident γδ T cell subpopulations, with an emphasis on genome-wide studies and their added value to elucidate the regulation of γδ T cell differentiation at the transcriptional and epigenetic (chromatin) levels.

  6. Innate Memory T cells

    PubMed Central

    Jameson, Stephen C.; Lee, You Jeong; Hogquist, Kristin A.

    2015-01-01

    Memory T cells are usually considered to be a feature of a successful immune response against a foreign antigen, and such cells can mediate potent immunity. However, in mice, alternative pathways have been described, through which naïve T cells can acquire the characteristics and functions of memory T cells without encountering specific foreign antigen or the typical signals required for conventional T cell differentiation. Such cells reflect a response to the internal rather the external environment, and hence such cells are called innate memory T cells. In this review, we describe how innate memory subsets were identified, the signals that induce their generation and their functional properties and potential role in the normal immune response. The existence of innate memory T cells in mice raises questions about whether parallel populations exist in humans, and we discuss the evidence for such populations during human T cell development and differentiation. PMID:25727290

  7. Strong TCR-mediated signals suppress integrated stress responses induced by KDELR1 deficiency in naive T cells.

    PubMed

    Kamimura, Daisuke; Arima, Yasunobu; Tsuruoka, Mineko; Jiang, Jing-Jing; Bando, Hidenori; Meng, Jie; Sabharwal, Lavannya; Stofkova, Andrea; Nishikawa, Naoki; Higuchi, Kotaro; Ogura, Hideki; Atsumi, Toru; Murakami, Masaaki

    2016-03-01

    KDEL receptor 1 (KDELR1) regulates integrated stress responses (ISR) to promote naive T-cell survival in vivo. In a mouse line having nonfunctional KDELR1, T-Red (naive T-cell reduced) mice, polyclonal naive T cells show excessive ISR and eventually undergo apoptosis. However, breeding T-Red mice with TCR-transgenic mice bearing relatively high TCR affinity rescued the T-Red phenotype, implying a link between ISR-induced apoptosis and TCR-mediated signaling. Here, we showed that strong TCR stimulation reduces ISR in naive T cells. In mice lacking functional KDELR1, surviving naive T cells expressed significantly higher levels of CD5, a surrogate marker of TCR self-reactivity. In addition, higher TCR affinity/avidity was confirmed using a tetramer dissociation assay on the surviving naive T cells, suggesting that among the naive T-cell repertoire, those that receive relatively stronger TCR-mediated signals via self-antigens survive enhanced ISR. Consistent with this observation, weak TCR stimulation with altered peptide ligands decreased the survival and proliferation of naive T cells, whereas stimulation with ligands having higher affinity had no such effect. These results suggest a novel role of TCR-mediated signals in the attenuation of ISR in vivo.

  8. An assessment of common marmoset (Callithrix jacchus) γ9(+) T cells and their response to phosphoantigen in vitro.

    PubMed

    Rowland, Caroline A; Laws, Thomas R; Oyston, Petra C F

    2012-12-01

    γ9δ2 T cells are a primate-specific γδ T cell subtype that expand and become activated during infection, responding directly to phosphoantigens which are by-products of essential metabolic pathways in both bacteria and mammals. Analogues of natural phosphoantigens have been developed as potential immunotherapeutics for treatment of tumours and infectious diseases. Several non-human primate models have been used in preclinical studies, however, little is known about marmoset γ9δ2 T cell responses. We identified γ9(+) T cells in various tissues in the marmoset and determined that these cells respond to phosphoantigen in a similar manner to human γ9δ2 T cells in vitro. Both human γ9δ2 T cells and marmoset γ9(+) T cells were able to reduce growth of the intracellular bacterium Burkholderia pseudomallei in vitro following expansion with phosphoantigen. This suggests that the marmoset is an appropriate model for examining the immunotherapeutic potential of compounds which target γ9δ2 T cells.

  9. Role of T cell TGF beta signaling in intestinal cytokine responses and helminthic immune modulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Colonization with helminthic parasites down-regulates inflammation in murine colitis and improves activity scores in human inflammatory bowel disease. Helminths induce mucosal regulatory T cells, which are important for intestinal immunologic homeostasis. Regulatory T cell function involves cytoki...

  10. Functional differences in hepatitis C virus nonstructural (NS) 3/4A- and 5A-specific T cell responses

    PubMed Central

    Holmström, Fredrik; Chen, Margaret; Balasiddaiah, Anangi; Sällberg, Matti; Ahlén, Gustaf; Frelin, Lars

    2016-01-01

    The hepatitis C virus nonstructural (NS) 3/4A and NS5A proteins are major targets for the new direct-acting antiviral compounds. Both viral proteins have been suggested as modulators of the response to the host cell. We have shown that NS3/4A- and NS5A-specific T cell receptors confer different effector functions, and that killing of NS3/4A-expressing hepatocytes is highly dependent on IFN-γ. We here characterize the functional differences in the T cell responses to NS3/4A and NS5A. NS3/4A- and NS5A-specific T cells could be induced at various frequencies in wild-type-, NS3/4A-, and NS5A-transgenic mice. Priming of NS5A-specific T cells required a high DNA dose, and was unlike NS3/4A dependent on both CD4+ and CD8+ T cells, but less influenced by CD25+/GITR+ regulatory T cells. The presence of IL-12 greatly improved specific CD8+ T cell priming by NS3/4A but not by NS5A, suggesting a less dependence of IFN-γ for NS5A. This notion was supported by the observation that NS5A-specific T cells could eliminate NS5A-expressing hepatocytes also in the absence of IFN-γ-receptor-2. This supports that NS3/4A- and NS5A-specific T cells become activated and eliminate antigen expressing, or infected hepatocytes, by distinct mechanisms, and that NS5A-specific T cells show an overall less dependence of IFN-γ. PMID:27141891

  11. Common Ewing sarcoma-associated antigens fail to induce natural T cell responses in both patients and healthy individuals.

    PubMed

    Altvater, Bianca; Kailayangiri, Sareetha; Theimann, Nadine; Ahlmann, Martina; Farwick, Nicole; Chen, Christiane; Pscherer, Sibylle; Neumann, Ilka; Mrachatz, Gabriele; Hansmeier, Anna; Hardes, Jendrik; Gosheger, Georg; Juergens, Heribert; Rossig, Claudia

    2014-10-01

    Disseminated or relapsed Ewing sarcoma (EwS) has remained fatal in the majority of patients. A promising approach to preventing relapse after conventional therapy is to establish tumor antigen-specific immune control. Efficient and specific T cell memory against the tumor depends on the expansion of rare T cells with native specificity against target antigens overexpressed by the tumor. Candidate antigens in EwS include six-transmembrane epithelial antigen of the prostate-1 (STEAP1), and the human cancer/testis antigens X-antigen family member 1 (XAGE1) and preferentially expressed antigen in melanoma (PRAME). Here, we screened normal donors and EwS patients for the presence of circulating T cells reactive with overlapping peptide libraries of these antigens by IFN-γ Elispot analysis. The majority of 22 healthy donors lacked detectable memory T cell responses against STEAP1, XAGE1 and PRAME. Moreover, ex vivo detection of T cells specific for these antigens in both blood and bone marrow were limited to a minority of EwS patients and required nonspecific T cell prestimulation. Cytotoxic T cells specific for the tumor-associated antigens were efficiently and reliably generated by in vitro priming using professional antigen-presenting cells and optimized cytokine stimulation; however, these T cells failed to interact with native antigen processed by target cells and with EwS cells expressing the antigen. We conclude that EwS-associated antigens fail to induce efficient T cell receptor (TCR)-mediated antitumor immune responses even under optimized conditions. Strategies based on TCR engineering could provide a more effective means to manipulating T cell immunity toward targeted elimination of tumor cells.

  12. Abacavir induced T cell reactivity from drug naïve individuals shares features of allo-immune responses.

    PubMed

    Adam, Jacqueline; Wuillemin, Natascha; Watkins, Stephan; Jamin, Heidi; Eriksson, Klara K; Villiger, Peter; Fontana, Stefano; Pichler, Werner J; Yerly, Daniel

    2014-01-01

    Abacavir hypersensitivity is a severe hypersensitivity reaction which occurs exclusively in carriers of the HLA-B*57∶01 allele. In vitro culture of PBMC with abacavir results in the outgrowth of abacavir-reacting CD8+ T cells, which release IFNγ and are cytotoxic. How this immune response is induced and what is recognized by these T cells is still a matter of debate. We analyzed the conditions required to develop an abacavir-dependent T cell response in vitro. The abacavir reactivity was independent of co-stimulatory signals, as neither DC maturation nor release of inflammatory cytokines were observed upon abacavir exposure. Abacavir induced T cells arose in the absence of professional APC and stemmed from naïve and memory compartments. These features are reminiscent of allo-reactivity. Screening for allo-reactivity revealed that about 5% of generated T cell clones (n = 136) from three donors were allo-reactive exclusively to the related HLA-B*58∶01. The addition of peptides which can bind to the HLA-B*57∶01-abacavir complex and to HLA-B*58∶01 during the induction phase increased the proportion of HLA-B*58∶01 allo-reactive T cell clones from 5% to 42%. In conclusion, abacavir can alter the HLA-B*57∶01-peptide complex in a way that mimics an allo-allele ('altered self-allele') and create the potential for robust T cell responses.

  13. Involvement of Different CD4+ T Cell Subsets Producing Granzyme B in the Immune Response to Leishmania major Antigens

    PubMed Central

    Naouar, Ikbel; Boussoffara, Thouraya; Ben Ahmed, Melika; Belhaj Hmida, Nabil; Gharbi, Adel; Gritli, Sami; Ben Salah, Afif; Louzir, Hechmi

    2014-01-01

    The nature of effector cells and the potential immunogenicity of Leishmania major excreted/secreted proteins (LmES) were evaluated using peripheral blood mononuclear cells (PBMCs) from healed zoonotic cutaneous leishmaniasis individuals (HZCL) and healthy controls (HC). First, we found that PBMCs from HZCL individuals proliferate and produce high levels of IFN-γ and granzyme B (GrB), used as a marker of activated cytotoxic T cells, in response to the parasite antigens. IFN-γ is produced by CD4+ T cells, but unexpectedly GrB is also produced by CD4+ T cells in response to stimulation with LmES, which were found to be as effective as soluble Leishmania antigens to induce proliferation and cytokine production by PBMCs from immune individuals. To address the question of regulatory T cell (Tregs) involvement, the frequency of circulating Tregs was assessed and found to be higher in HZCL individuals compared to that of HC. Furthermore, both CD4+CD25+ and CD4+CD25− T cells, purified from HZCL individuals, produced IFN-γ and GrB when stimulated with LmES. Additional experiments showed that CD4+CD25+CD127dim/− Tregs were involved in GrB production. Collectively, our data indicate that LmES are immunogenic in humans and emphasize the involvement of CD4+ T cells including activated and regulatory T cells in the immune response against parasite antigens. PMID:25104882

  14. Immune responses induced by T-cell vaccination in patients with rheumatoid arthritis

    PubMed Central

    Ivanova, Irina; Seledtsova, Galina; Mamaev, Sergey; Shishkov, Alexey; Seledtsov, Viktor

    2014-01-01

    Patients with rheumatoid arthritis (RA) were treated with a cellular vaccine, which consisted of autologous collagen-reactive T-cells. This study showed that antigen-specific proliferative activity of the peripheral blood mononuclear cells was significantly downregulated after T-cell vaccination in RA patients. T-cell vaccination resulted in a statistically significant decrease in plasma IFNγ levels and a concomitant increase in IL-4 levels in treated patients. Accordingly, following T-cell vaccination the number of IFNγ-producing CD4+ and CD8+ T-cells was decreased by 1.6–1.8-fold, which was paralleled by 1.7-fold increases in IL-4-producing CD4+ T-cells. In addition, the present study showed 5–7-fold increase in the CD8+CD45RO+CD62L– effector memory T-cells and central memory T-cells (both CD4+ CD45RO+CD62L+ T-cells and CD8+CD45RO+CD62L+ T-cells) in RA patients, as compared with healthy individuals. We observed significant reduction in CD4+ and CD8+ central memory T-cells, as well as reduction in CD8+ effector memory T-cells in vaccinated patients in the course of the treatment. We also demonstrated that CD4+CD25+FoxP3+ regulatory T-cell levels were significantly up-regulated in the peripheral blood of RA patients following T-cell vaccination. However, CD4+CD25-FoxP3+ Т-cell levels did not significantly change during the entire T-cell vaccination course. In conclusion, the T-cell immunotherapy regimen used resulted in the clinical improvement, which was achieved in 87% patients. PMID:24633313

  15. Loss of immunization-induced epitope-specific CD4 T-cell response following anaplasma marginale infection requires presence of the T-cell epitope on the pathogen and is not associated with an increase in lymphocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have shown that in cattle previously immunized with outer membrane proteins, infection with Anaplasma marginale induces a functionally exhausted CD4 T-cell response to the A. marginale immunogen. Furthermore, T-cell responses following infection in nonimmunized cattle had a delayed onset and were...

  16. MPLA incorporation into DC-targeting glycoliposomes favours anti-tumour T cell responses.

    PubMed

    Boks, Martine A; Ambrosini, Martino; Bruijns, Sven C; Kalay, Hakan; van Bloois, Louis; Storm, Gert; Garcia-Vallejo, Juan J; van Kooyk, Yvette

    2015-10-28

    Dendritic cells (DC) are attractive targets for cancer immunotherapy as they initiate strong and long-lived tumour-specific T cell responses. DC can be effectively targeted in vivo with tumour antigens by using nanocarriers such as liposomes. Cross-presentation of tumour antigens is enhanced with strong adjuvants such as TLR ligands. However, often these adjuvants have off-target effects, and would benefit from a DC-specific targeting strategy, similar to the tumour antigen. The goal of this study was to develop a strategy for specifically targeting DC with tumour antigen and adjuvant by using glycoliposomes. We have generated liposomes containing the glycan Lewis(Le)(X) which is highly specific for the C-type lectin receptor DC-SIGN expressed by DC. Le(X)-modified liposomes were taken up by human monocyte-derived DC in a DC-SIGN-specific manner. As adjuvants we incorporated the TLR ligands Pam3CySK4, Poly I:C, MPLA and R848 into liposomes and compared their adjuvant capacity on DC. Incorporation of the TLR4 ligand MPLA into glycoliposomes induced DC maturation and production of pro-inflammatory cytokines, in a DC-SIGN-specific manner, and DC activation was comparable to administration of soluble MPLA. Incorporation of MPLA into glycoliposomes significantly enhanced antigen cross-presentation of the melanoma tumour antigen gp100280-288 peptide to CD8(+) T cells compared to non-glycosylated MPLA liposomes. Importantly, antigen cross-presentation of the gp100280-288 peptide was significantly higher using MPLA glycoliposomes compared to the co-administration of soluble MPLA with glycoliposomes. Taken together, our data demonstrates that specific targeting of a gp100 tumour antigen and the adjuvant MPLA to DC-SIGN-expressing DC enhances the uptake of peptide-containing liposomes, the activation of DC, and induces tumour antigen-specific CD8(+) T cell responses. These data demonstrate that adjuvant-containing glycoliposome-based vaccines targeting DC-SIGN(+) DC

  17. Peptide-MHC Cellular Microarray with Innovative Data Analysis System for Simultaneously Detecting Multiple CD4 T-Cell Responses

    PubMed Central

    Ge, Xinhui; Gebe, John A.; Bollyky, Paul L.; James, Eddie A.; Yang, Junbao; Stern, Lawrence J.; Kwok, William W.

    2010-01-01

    Background Peptide:MHC cellular microarrays have been proposed to simultaneously characterize multiple Ag-specific populations of T cells. The practice of studying immune responses to complicated pathogens with this tool demands extensive knowledge of T cell epitopes and the availability of peptide:MHC complexes for array fabrication as well as a specialized data analysis approach for result interpretation. Methodology/Principal Findings We co-immobilized peptide:DR0401 complexes, anti-CD28, anti-CD11a and cytokine capture antibodies on the surface of chamber slides to generate a functional array that was able to detect rare Ag-specific T cell populations from previously primed in vitro T cell cultures. A novel statistical methodology was also developed to facilitate batch processing of raw array-like data into standardized endpoint scores, which linearly correlated with total Ag-specific T cell inputs. Applying these methods to analyze Influenza A viral antigen-specific T cell responses, we not only revealed the most prominent viral epitopes, but also demonstrated the heterogeneity of anti-viral cellular responses in healthy individuals. Applying these methods to examine the insulin producing beta-cell autoantigen specific T cell responses, we observed little difference between autoimmune diabetic patients and healthy individuals, suggesting a more subtle association between diabetes status and peripheral autoreactive T cells. Conclusions/Significance The data analysis system is reliable for T cell specificity and functional testing. Peptide:MHC cellular microarrays can be used to obtain multi-parametric results using limited blood samples in a variety of translational settings. PMID:20634998

  18. Microsphere priming facilitates induction of potent therapeutic T-cell immune responses against autochthonous liver cancers.

    PubMed

    Brinkhoff, Benjamin; Ostroumov, Dmitrij; Heemcke, Jessica; Woller, Norman; Gürlevik, Engin; Manns, Michael P; Longerich, Thomas; Zender, Lars; Harty, John T; Kubicka, Stefan; Kühnel, Florian; Wirth, Thomas C

    2014-04-01

    Immunotherapy of solid tumors is often hampered by the low frequency of tumor-specific T cells elicited by current vaccination strategies. Here, we describe a prime-boost vaccination protocol based on the administration of antigen conjugated to poly-lactic-co-glycolic acid (PLGA) microspheres followed by booster vaccination with Listeria monocytogenes vectors, which rapidly generates potent immune responses within two weeks. Compared with conventional vaccination with antigen-pulsed dendritic cells, the use of PLGA microspheres resulted in immune responses of significantly higher magnitude, which could be further enhanced via coinjection of TLR 3 agonists. In an immunocompetent model of subcutaneous hepatocellular carcinoma, PLGA/Listeria vaccination resulted in complete remission of established tumors and prolonged survival. To further test the efficacy of the novel vaccination for the treatment of solid tumors, we developed an orthotopic liver cancer model based on the injection of transposon-flanked plasmids expressing oncogenes and model antigens. In this transgenic mouse model of liver cancer, PLGA/Listeria vaccination resulted in eradication of liver tumors, long-term survival of animals and establishment of stable cancer-specific memory CD8(+) T-cell populations. Therefore, combined PLGA/Listeria vaccination holds promise as a novel immunotherapeutic option for the treatment of solid cancers and as a means to boost the therapeutic efficacy of established cancer vaccines.

  19. Specific CD8+ T cell response immunotherapy for hepatocellular carcinoma and viral hepatitis

    PubMed Central

    Moreno-Cubero, Elia; Larrubia, Juan-Ramón

    2016-01-01

    Hepatocellular carcinoma (HCC), chronic hepatitis B (CHB) and chronic hepatitis C (CHC) are characterized by exhaustion of the specific CD8+ T cell response. This process involves enhancement of negative co-stimulatory molecules, such as programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte antigen-4 (CTLA-4), 2B4, Tim-3, CD160 and LAG-3, which is linked to intrahepatic overexpression of some of the cognate ligands, such as PD-L1, on antigen presenting cells and thereby favouring a tolerogenic environment. Therapies that disrupt these negative signalling mechanisms represent promising therapeutic tools with the potential to restore reactivity of the specific CD8+ T cell response. In this review we discuss the impressive in vitro and in vivo results that have been recently achieved in HCC, CHB and CHC by blocking these negative receptors with monoclonal antibodies against these immune checkpoint modulators. The article mainly focuses on the role of CTLA-4 and PD-1 blocking monoclonal antibodies, the first ones to have reached clinical practice. The humanized monoclonal antibodies against CTLA-4 (tremelimumab and ipilimumab) and PD-1 (nivolumab and pembrolizumab) have yielded good results in testing of HCC and chronic viral hepatitis patients. Trelimumab, in particular, has shown a significant increase in the time to progression in HCC, while nivolumab has shown a remarkable effect on hepatitis C viral load reduction. The research on the role of ipilimumab, nivolumab and pembrolizumab on HCC is currently underway. PMID:27605882

  20. Alarmin’ Immunologists: IL-33 as a Putative Target for Modulating T Cell-Dependent Responses

    PubMed Central

    Gajardo Carrasco, Tania; Morales, Rodrigo A.; Pérez, Francisco; Terraza, Claudia; Yáñez, Luz; Campos-Mora, Mauricio; Pino-Lagos, Karina

    2015-01-01

    IL-33 is a known member of the IL-1 cytokine superfamily classically named “atypical” due to its diverse functions. The receptor for this cytokine is the ST2 chain (or IL-1RL1), part of the IL-1R family, and the accessory chain IL-1R. ST2 can be found as both soluble and membrane-bound forms, property that explains, at least in part, its wide range of functions. IL-33 has increasingly gained our attention as a potential target to modulate immune responses. At the beginning, it was known as one of the participants during the development of allergic states and other Th2-mediated responses and it is now accepted that IL-33 contributes to Th1-driven pathologies as demonstrated in animal models of experimental autoimmune encephalomyelitis (EAE), collagen-induced arthritis, and trinitrobenzene sulfonic acid-induced experimental colitis, among others. Interestingly, current data are placing IL-33 as a novel regulator of immune tolerance by affecting regulatory T cells (Tregs); although the mechanism is not fully understood, it seems that dendritic cells and myeloid suppressor-derived cells may be cooperating in the generation and/or establishment of IL-33-mediated tolerance. Here, we review the most updated literature on IL-33, its role on T cell biology, and its impact in immune tolerance. PMID:26082774

  1. The role of ICOS in directing T cell responses: ICOS-dependent induction of T cell anergy by tolerogenic dendritic cells.

    PubMed

    Tuettenberg, Andrea; Huter, Eva; Hubo, Mario; Horn, Julia; Knop, Jürgen; Grimbacher, Bodo; Kroczek, Richard A; Stoll, Sabine; Jonuleit, Helmut

    2009-03-15

    Tolerogenic dendritic cells (DC) play an important role in maintaining peripheral T cell tolerance in steady-state conditions through induction of anergic, IL-10-producing T cells with suppressive properties. ICOS, an activation-induced member of the CD28 family on T cells, is involved in the induction of IL-10, which itself could contribute to induction of anergy and development of suppressive T cells. Therefore, we analyzed the functional role of ICOS in the differentiation process of human CD4(+) T cells upon their interaction with tolerogenic DC. We compared the functional properties of CD4(+) T cells from healthy volunteers and ICOS-deficient patients after stimulation with tolerogenic DC. We report that induction of T cell anergy and suppressive capacity is completely blocked after knockdown of ICOS expression in T cells as well as after blocking of ICOS-ICOS ligand interaction in DC/T cell cocultures. Moreover, CD4(+) T cells from ICOS-deficient patients were completely resistant to anergy induction and differentiation into suppressive T cells even after supplementation of IL-10. Furthermore, ICOS/ICOS ligand interaction stabilizes IL-10R expression on T cells and thus renders them sensitive to IL-10 effects. Taken together, these results indicate a crucial role for ICOS in the induction of peripheral tolerance maintained by tolerogenic DC mediated mostly via an IL-10-independent mechanism.

  2. Increased Membrane Cholesterol in Lymphocytes Diverts T-Cells toward an Inflammatory Response

    PubMed Central

    Surls, Jacqueline; Nazarov-Stoica, Cristina; Kehl, Margaret; Olsen, Cara; Casares, Sofia; Brumeanu, Teodor-D.

    2012-01-01

    Cell signaling for T-cell growth, differentiation, and apoptosis is initiated in the cholesterol-rich microdomains of the plasma membrane known as lipid rafts. Herein, we investigated whether enrichment of membrane cholesterol in lipid rafts affects antigen-specific CD4 T-helper cell functions. Enrichment of membrane cholesterol by 40–50% following squalene administration in mice was paralleled by an increased number of resting CD4 T helper cells in periphery. We also observed sensitization of the Th1 differentiation machinery through co-localization of IL-2Rα, IL-4Rα, and IL-12Rβ2 subunits with GM1 positive lipid rafts, and increased STAT-4 and STAT-5 phosphorylation following membrane cholesterol enrichment. Antigen stimulation or CD3/CD28 polyclonal stimulation of membrane cholesterol-enriched, resting CD4 T-cells followed a path of Th1 differentiation, which was more vigorous in the presence of increased IL-12 secretion by APCs enriched in membrane cholesterol. Enrichment of membrane cholesterol in antigen-specific, autoimmune Th1 cells fostered their organ-specific reactivity, as confirmed in an autoimmune mouse model for diabetes. However, membrane cholesterol enrichment in CD4+ Foxp3+ T-reg cells did not alter their suppressogenic function. These findings revealed a differential regulatory effect of membrane cholesterol on the function of CD4 T-cell subsets. This first suggests that membrane cholesterol could be a new therapeutic target to modulate the immune functions, and second that increased membrane cholesterol in various physiopathological conditions may bias the immune system toward an inflammatory Th1 type response. PMID:22723880

  3. Recombinant pro-apoptotic Mycobacterium tuberculosis generates CD8+ T cell responses against human immunodeficiency virus type 1 Env and M. tuberculosis in neonatal mice.

    PubMed

    Ranganathan, Uma Devi K; Larsen, Michelle H; Kim, John; Porcelli, Steven A; Jacobs, William R; Fennelly, Glenn J

    2009-12-10

    Mycobacterium bovis BCG is an attractive vaccine vector against breast milk HIV transmission because it elicits Th1-type responses in newborns. However, BCG causes disease in HIV-infected infants. Genetically attenuated Mycobacterium tuberculosis (Mtb) mutants represent a safer alternative for immunocompromised populations. In the current study, we compared the immunogenicity in mice of three different recombinant attenuated Mtb strains expressing an HIV envelope (Env) antigen construct. Two of these strains (DeltalysA DeltapanCD Mtb and DeltaRD1 DeltapanCD Mtb) failed to induce significant levels of HIV Env-specific CD8(+) T cell responses. In striking contrast, an HIV-1 Env-expressing attenuated DeltalysA Mtb containing a deletion in secA2, which encodes a virulence-related secretion system involved in evading adaptive immunity, generated consistently measurable Env-specific CD8(+) T cell responses that were significantly greater than those observed after immunization with BCG expressing HIV Env. Similarly, another strain of DeltalysA DeltasecA2 Mtb expressing SIV Gag induced Gag- and Mtb-specific CD8(+) T cells producing perforin or IFNgamma, and Gag-specific CD4(+) T cells producing IFNgamma within 3 weeks after immunization in adult mice; in addition, IFNgamma-producing Gag-specific CD8(+) T cells and Mtb-specific CD4(+) T cells were observed in neonatal mice within 1 week of immunization. We conclude that DeltalysA DeltasecA2 Mtb is a promising vaccine platform to construct a safe combination HIV-TB vaccine for use in neonates.

  4. Myristoylation increases the CD8+T-cell response to a GFP prototype antigen delivered by modified vaccinia virus Ankara.

    PubMed

    Marr, Lisa; Lülf, Anna-Theresa; Freudenstein, Astrid; Sutter, Gerd; Volz, Asisa

    2016-04-01

    Activation of CD8(+)T-cells is an essential part of immune responses elicited by recombinant modified vaccinia virus Ankara (MVA). Strategies to enhance T-cell responses to antigens may be particularly necessary for broadly protective immunization against influenza A virus infections or for candidate vaccines targeting chronic infections and cancer. Here, we tested recombinant MVAs that targeted a model antigen, GFP, to different localizations in infected cells. In vitro characterization demonstrated that GFP accumulated in the nucleus (MVA-nls-GFP), associated with cellular membranes (MVA-myr-GFP) or was equally distributed throughout the cell (MVA-GFP). On vaccination, we found significantly higher levels of GFP-specific CD8(+)T-cells in MVA-myr-GFP-vaccinated BALB/c mice than in those immunized with MVA-GFP or MVA-nls-GFP. Thus, myristoyl modification may be a useful strategy to enhance CD8(+)T-cell responses to MVA-delivered target antigens.

  5. Lack of IL-15 results in the suboptimal priming of CD4+ T cell response against an intracellular parasite.

    PubMed

    Combe, Crescent L; Moretto, Magali M; Schwartzman, Joseph D; Gigley, Jason P; Bzik, David J; Khan, Imtiaz A

    2006-04-25

    IFN-gamma-producing CD4+ T cells, although important for protection against acute Toxoplasma gondii infection, can cause gut pathology, which may prove to be detrimental for host survival. Here we show that mice lacking IL-15 gene develop a down-regulated IFN-gamma-producing CD4+ T cell response against the parasite, which leads to a reduction in gut necrosis and increased level of survival against infection. Moreover, transfer of immune CD4+ T cells from WT to IL-15-/- mice reversed inhibition of gut pathology and caused mortality equivalent to levels of parental WT mice. Down-regulated CD4+ T cell response in the absence of IL-15, manifested as reduced antigen-specific proliferation, was due to defective priming of the T cell subset by dendritic cells (DCs) of these animals. When stimulated with antigen-pulsed DCs from WT mice, CD4+ T cells from IL-15-/- mice were primed optimally, and robust proliferation of these cells was observed. A defect in the DCs of knockout mice was further confirmed by their reduced ability to produce IL-12 upon stimulation with Toxoplasma lysate antigen. Addition of exogenous IL-15 to DC cultures from knockout mice led to increased IL-12 production by these cells and restored their ability to prime an optimal parasite-specific CD4+ T cell response. To our knowledge, this is the first demonstration of the role of IL-15 in the development of CD4+ T cell immunity against an intracellular pathogen. Furthermore, based on these observations, targeting of IL-15 should have a beneficial effect on individuals suffering from CD4+ T cell-mediated autoimmune diseases.

  6. Induction of Multifunctional Broadly Reactive T Cell Responses by a Plasmodium vivax Circumsporozoite Protein Recombinant Chimera.

    PubMed

    Cabrera-Mora, Monica; Fonseca, Jairo Andres; Singh, Balwan; Oliveira-Ferreira, Joseli; Lima-Junior, Josué da Costa; Calvo-Calle, J Mauricio; Moreno, Alberto

    2015-09-01

    Plasmodium vivax is the most widespread species of Plasmodium, causing up to 50% of the malaria cases occurring outside sub-Saharan Africa. An effective vaccine is essential for successful control and potential eradication. A well-characterized vaccine candidate is the circumsporozoite protein (CSP). Preclinical and clinical trials have shown that both antibodies and cellular immune responses have been correlated with protection induced by immunization with CSP. On the basis of our reported approach of developing chimeric Plasmodium yoelii proteins to enhance protective efficacy, we designed PvRMC-CSP, a recombinant chimeric protein based on the P. vivax CSP (PvCSP). In this engineered protein, regions of the PvCSP predicted to contain human T cell epitopes were genetically fused to an immunodominant B cell epitope derived from the N-terminal region I and to repeat sequences representing the two types of PvCSP repeats. The chimeric protein was expressed in soluble form with high yield. As the immune response to PvCSP has been reported to be genetically restricted in the murine model, we tested the immunogenicity of PvRMC-CSP in groups of six inbred strains of mice. PvRMC-CSP was able to induce robust antibody responses in all the mouse strains tested. Synthetic peptides representing the allelic forms of the P. vivax CSP were also recognized to a similar extent regardless of the mouse strain. Furthermore, the immunization regimen induced high frequencies of multifunctional CD4(+) and CD8(+) PvRMC-CSP-specific T cells. The depth and breadth of the immune responses elicited suggest that immunization with PvRMC-CSP can circumvent the genetic restriction of the immune response to P. vivax CSP. Interestingly, PvRMC-CSP was also recognized by naturally acquired antibodies from individuals living in areas where malaria is endemic. These features make PvRMC-CSP a promising vaccine candidate for further development.

  7. Rapid selection of escape mutants by the first CD8 T cell responses in acute HIV-1 infection

    SciTech Connect

    Korber, Bette Tina Marie

    2008-01-01

    The recent failure of a vaccine that primes T cell responses to control primary HIV-1 infection has raised doubts about the role of CD8+ T cells in early HIV-1 infection. We studied four patients who were identified shortly after HIV-1 infection and before seroconversion. In each patient there was very rapid selection of multiple HIV-1 escape mutants in the transmitted virus by CD8 T cells, including examples of complete fixation of non-synonymous substitutions within 2 weeks. Sequencing by single genome amplification suggested that the high rate of virus replication in acute infection gave a selective advantage to virus molecules that contained simultaneous and gained sequential T cell escape mutations. These observations show that whilst early HIV-1 specific CD8 T cells can act against virus, rapid escape means that these T cell responses are unlikely to benefit the patient and may in part explain why current HIV-1 T cell vaccines may not be protective.

  8. Timing of CD8+ T cell responses in relation to commencement of capillary leakage in children with dengue.

    PubMed

    Dung, Nguyen Thi Phuong; Duyen, Huynh Thi Le; Thuy, Nguyen Thi Van; Ngoc, Tran Van; Chau, Nguyen Van Vinh; Hien, Tran Tinh; Rowland-Jones, Sarah L; Dong, Tao; Farrar, Jeremy; Wills, Bridget; Simmons, Cameron P

    2010-06-15

    Immune activation is a feature of dengue hemorrhagic fever (DHF) and CD8+ T cell responses in particular have been suggested as having a role in the vasculopathy that characterizes this disease. By phenotyping CD8+ T cells (CD38+/HLA-DR+, CD38+/Ki-67+, or HLA-DR+/Ki-67+) in serial blood samples from children with dengue, we found no evidence of increased CD8+ T cell activation prior to the commencement of resolution of viremia or hemoconcentration. Investigations with MHC class I tetramers to detect NS3(133-142)-specific CD8+ T cells in two independent cohorts of children suggested the commencement of hemoconcentration and thrombocytopenia in DHF patients generally begins before the appearance of measurable frequencies of NS3(133-142)-specific CD8+ T cells. The temporal mismatch between the appearance of measurable surface activated or NS3(133-142)-specific CD8+ T cells suggests that these cells are sequestered at sites of infection, have phenotypes not detected by our approach, or that other mechanisms independent of CD8+ T cells are responsible for early triggering of capillary leakage in children with DHF.

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

    PubMed Central

    Swee, Lee Kim; Tan, Zhen Wei; Sanecka, Anna; Yoshida, Nagisa; Patel, Harshil; Grotenbreg, Gijsbert; Ploegh, Hidde L.

    2016-01-01

    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-2b haplotype. We measured the affinity of three structurally distinct CD8 T-cell-derived TCRs that recognize the identical H-2 Ld-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. PMID:27881740

  10. Comprehensive analysis of dengue virus-specific responses supports an HLA-linked protective role for CD8+ T cells.

    PubMed

    Weiskopf, Daniela; Angelo, Michael A; de Azeredo, Elzinandes L; Sidney, John; Greenbaum, Jason A; Fernando, Anira N; Broadwater, Anne; Kolla, Ravi V; De Silva, Aruna D; de Silva, Aravinda M; Mattia, Kimberly A; Doranz, Benjamin J; Grey, Howard M; Shresta, Sujan; Peters, Bjoern; Sette, Alessandro

    2013-05-28

    The role of CD8(+) T cells in dengue virus infection and subsequent disease manifestations is not fully understood. According to the original antigenic sin theory, skewing of T-cell responses induced by primary infection with one serotype causes less effective response upon secondary infection with a different serotype, predisposing individuals to severe disease. A comprehensive analysis of CD8(+) responses in the general population from the Sri Lankan hyperendemic area, involving the measurement of ex vivo IFNγ responses associated with more than 400 epitopes, challenges the original antigenic sin theory. Although skewing of responses toward primary infecting viruses was detected, this was not associated with impairment of responses either qualitatively or quantitatively. Furthermore, we demonstrate higher magnitude and more polyfunctional responses for HLA alleles associated with decreased susceptibility to severe disease, suggesting that a vigorous response by multifunctional CD8(+) T cells is associated with protection from dengue virus disease.

  11. Discovery and Subtyping of Neo-Epitope Specific T-Cell Responses for Cancer Immunotherapy: Addressing the Mutanome.

    PubMed

    Diken, Mustafa; Vormehr, Mathias; Grunwitz, Christian; Kreiter, Sebastian; Türeci, Özlem; Sahin, Ugur

    2017-01-01

    Cancer accumulates 10s to 1000s of genomic mutations of which a fraction is immunogenic and may serve as an Achilles' heel of tumor cells. Mutation-specific T cells can recognize these antigens and destroy malignant cells. Strategies to immunotherapeutically address individual tumor mutations employing peptide or mRNA based vaccines are now actively investigated in mice and humans. An important step of determining the therapeutic potential of a mutanome vaccine is the detection of mutation reactive T-cell responses. In this chapter we provide protocols to identify and subtype mutation specific T cells in mice based on IFN-γ ELISpot and flow cytometry.

  12. NK cells require antigen-specific memory CD4+ T cells to mediate superior effector functions during HSV-2 recall responses in vitro.

    PubMed

    Chen, Branson; Lee, Amanda J; Chew, Marianne V; Ashkar, Ali A

    2016-12-14

    Natural killer (NK) cells have an important role in mounting protective innate responses against genital herpes simplex virus type 2 (HSV-2) infections. However their role as effectors in adaptive immune responses against HSV-2 is unclear. Here, we demonstrate that NK cells from C57BL/6 mice in an ex vivo splenocyte culture produce significantly more interferon γ (IFN-γ) upon re-exposure to HSV-2 antigens in a mouse model of genital HSV-2 immunization. We find that naïve NK cells do not require any prior stimulation or priming to be activated to produce IFN-γ. Our results demonstrate that HSV-2-experienced CD4(+) T cells have a crucial role in coordinating NK cell activation and that their presence during HSV-2 antigen presentation is required to activate NK cells in this model of secondary immune response. We also examined the requirement of cell-to-cell contacts for both CD4(+) T cells and NK cells. NK cells are dependent on direct interactions with other HSV-2-experienced splenocytes, and CD4(+) T cells need to be in close proximity to NK cells to activate them. This study revealed that NK cells do not exhibit any memory toward HSV-2 antigens and, in fact, require specific interactions with HSV-2-experienced CD4(+) T cells to produce IFN-γ.

  13. CD8+ T-cell responses against hemoglobin-beta prevent solid tumor growth.

    PubMed

    Komita, Hideo; Zhao, Xi; Taylor, Jennifer L; Sparvero, Louis J; Amoscato, Andrew A; Alber, Sean; Watkins, Simon C; Pardee, Angela D; Wesa, Amy K; Storkus, Walter J

    2008-10-01

    Bone marrow-derived dendritic cells engineered using recombinant adenovirus to secrete high levels of IL-12p70 dramatically inhibited the growth of established CMS4 sarcomas in BALB/c mice after intratumoral administration. An analysis of splenic CD8(+) T cells in regressor mice revealed a strong, complex reactivity pattern against high-performance liquid chromatography (HPLC)-resolved peptides isolated by acid elution from single-cell suspensions of surgically resected CMS4 lesions. Mass spectrometry analyses defined two major overlapping peptide species that derive from the murine hemoglobin-beta (HBB) protein within the most stimulatory HPLC fractions. Although cultured CMS4 tumor cells failed to express HBB mRNA based on reverse transcription-PCR analyses, prophylactic vaccination of BALB/c mice with vaccines containing HBB peptides promoted specific CD8(+) T-cell responses that protected mice against a subsequent challenge with CMS4 or unrelated syngeneic (HBB(neg)) tumors of divergent histology (sarcoma, carcinomas of the breast or colon). In situ imaging suggested that vaccines limit or destabilize tumor-associated vascular structures, potentially by promoting immunity against HBB+ vascular pericytes. Importantly, there were no untoward effects of vaccination with the HBB peptide on peripheral RBC numbers, RBC hemoglobin content, or vascular structures in the brain or eye.

  14. CD8+ T Cell Responses Against Hemoglobin-β Prevent Solid Tumor Growth

    PubMed Central

    Komita, Hideo; Zhao, Xi; Taylor, Jennifer L.; Sparvero, Louis J.; Amoscato, Andrew A.; Alber, Sean; Watkins, Simon C.; Pardee, Angela D.; Wesa, Amy K.; Storkus, Walter J.

    2008-01-01

    Bone marrow-derived dendritic cells (DCs) engineered using recombinant adenovirus to secrete high levels of IL-12p70 dramatically inhibited the growth of established CMS4 sarcomas in BALB/c mice after intratumoral administration. An analysis of splenic CD8+ T cells in regressor mice revealed a strong, complex reactivity pattern against HPLC-resolved peptides isolated by acid elution from single-cell suspensions of surgically-resected CMS4 lesions. Mass spectrometry analyses defined 2 major overlapping peptide species that derive from the murine hemoglobin-β (HBB) protein within the most stimulatory HPLC fractions. Although cultured CMS4 tumor cells failed to express HBB mRNA based on RT-PCR analyses, prophylactic vaccination of BALB/c mice with vaccines containing HBB peptides promoted specific CD8+ T cell responses that protected mice against a subsequent challenge with CMS4, or unrelated syngenic (HBBneg) tumors of divergent histology (sarcoma, carcinomas of the breast or colon). In situ imaging suggested that vaccines limit or destabilize tumor-associated vascular structures, potentially by promoting immunity against HBB+ vascular pericytes. Importantly, there were no untoward effects of vaccination with the HBB peptide on peripheral red blood cell (RBC) numbers, RBC hemoglobin content or vascular structures in the brain or eye. PMID:18829566

  15. Characterization of guinea pig T cell responses elicited after EP-assisted delivery of DNA vaccines to the skin

    PubMed Central

    Schultheis, Katherine; Schaefer, Hubert; Yung, Bryan S.; Oh, Janet; Muthumani, Karuppiah; Humeau, Laurent; Broderick, Kate E.

    2016-01-01

    The skin is an ideal target tissue for vaccine delivery for a number of reasons. It is highly accessible, and most importantly, enriched in professional antigen presenting cells. Possessing strong similarities to human skin physiology and displaying a defined epidermis, the guinea pig is an appropriate model to study epidermal delivery of vaccine. However, whilst we have characterized the humoral responses in the guinea pig associated with skin vaccine protocols we have yet to investigate the T cell responses. In response to this inadequacy, we developed an IFN-γ ELISpot assay to characterize the cellular immune response in the peripheral blood of guinea pigs. Using a nucleoprotein (NP) influenza pDNA vaccination regimen, we characterized host T cell responses. After delivery of the DNA vaccine to the guinea pig epidermis we detected robust and rapid T cell responses. The levels of IFN-γ spot-forming units averaged approximately 5000 per million cells after two immunizations. These responses were broad in that multiple regions across the NP antigen elicited a T cell response. Interestingly, we identified a number of NP immunodominant T cell epitopes to be conserved across an outbred guinea pig population, a phenomenon which was also observed after immunization with a RSV DNA vaccine. We believe this data enhances our understanding of the cellular immune response elicited to a vaccine in guinea pigs, and globally, will advance the use of this model for vaccine development, especially those targeting skin as a delivery site. PMID:27894716

  16. Characterization of guinea pig T cell responses elicited after EP-assisted delivery of DNA vaccines to the skin.

    PubMed

    Schultheis, Katherine; Schaefer, Hubert; Yung, Bryan S; Oh, Janet; Muthumani, Karuppiah; Humeau, Laurent; Broderick, Kate E; Smith, Trevor R F

    2017-01-03

    The skin is an ideal target tissue for vaccine delivery for a number of reasons. It is highly accessible, and most importantly, enriched in professional antigen presenting cells. Possessing strong similarities to human skin physiology and displaying a defined epidermis, the guinea pig is an appropriate model to study epidermal delivery of vaccine. However, whilst we have characterized the humoral responses in the guinea pig associated with skin vaccine protocols we have yet to investigate the T cell responses. In response to this inadequacy, we developed an IFN-γ ELISpot assay to characterize the cellular immune response in the peripheral blood of guinea pigs. Using a nucleoprotein (NP) influenza pDNA vaccination regimen, we characterized host T cell responses. After delivery of the DNA vaccine to the guinea pig epidermis we detected robust and rapid T cell responses. The levels of IFN-γ spot-forming units averaged approximately 5000 per million cells after two immunizations. These responses were broad in that multiple regions across the NP antigen elicited a T cell response. Interestingly, we identified a number of NP immunodominant T cell epitopes to be conserved across an outbred guinea pig population, a phenomenon which was also observed after immunization with a RSV DNA vaccine. We believe this data enhances our understanding of the cellular immune response elicited to a vaccine in guinea pigs, and globally, will advance the use of this model for vaccine development, especially those targeting skin as a delivery site.

  17. T cell regulation of the thymus-independent antibody response to trinitrophenylated-Brucella abortus (TNP-BA)

    SciTech Connect

    Tanay, A.; Strober, S.

    1985-06-01

    The authors have previously observed a reduction of the T cell-dependent primary antibody response to dinitrophenylated keyhole limpet hemocyanin, and an enhancement of the T cell-independent response to trinitrophenylated Brucella abortus (TNP-BA) in BALB/c mice after treatment with total lymphoid irradiation (TLI). To elucidate the relative contribution of T and B cells to the enhanced T cell-independent antibody responses after TLI, a syngeneic primary adoptive transfer system was utilized whereby irradiated hosts were reconstituted with unfractionated spleen cells or a combination of purified T and B cells from TLI-treated and untreated control mice. Antibody responses of purified splenic B cells from TLI-treated BALB/c mice (TLI/B) to TNP-BA were enhanced 10-fold as compared with those of unfractionated (UF) spleen cells or B cells from normal (NL) BALB/c mice (NL/UF and NL/B, respectively). Splenic T cells from normal animals (NL/T) suppressed the anti-TNP-BA response of TLI/B by more than 100-fold. NL/T neither suppressed nor enhanced the response of NL/B. On the other hand, T cells from TLI-treated mice (TLI/T) enhanced by 100-fold the anti-TNP-BA response of NL/B, but neither suppressed nor enhanced the response of TLI/B. Thus, T cells can regulate the T cell-independent antibody response to TNP-BA. However, experimental manipulation of the T and B cell populations is needed to demonstrate the regulatory functions.

  18. Trypanosoma cruzi Subverts Host Cell Sialylation and May Compromise Antigen-specific CD8+ T Cell Responses*

    PubMed Central

    Freire-de-Lima, Leonardo; Alisson-Silva, Frederico; Carvalho, Sebastião T.; Takiya, Christina M.; Rodrigues, Maurício M.; DosReis, George A.; Mendonça-Previato, Lucia; Previato, José O.; Todeschini, Adriane R.

    2010-01-01

    Upon activation, cytotoxic CD8+ T lymphocytes are desialylated exposing β-galactose residues in a physiological change that enhances their effector activity and that can be monitored on the basis of increased binding of the lectin peanut agglutinin. Herein, we investigated the impact of sialylation mediated by trans-sialidase, a specific and unique Trypanosoma transglycosylase for sialic acid, on CD8+ T cell response of mice infected with T. cruzi. Our data demonstrate that T. cruzi uses its trans-sialidase enzyme to resialylate the CD8+ T cell surface, thereby dampening antigen-specific CD8+ T cell response that might favor its own persistence in the mammalian host. Binding of the monoclonal antibody S7, which recognizes sialic acid-containing epitopes on the 115-kDa isoform of CD43, was augmented on CD8+ T cells from ST3Gal-I-deficient infected mice, indicating that CD43 is one sialic acid acceptor for trans-sialidase activity on the CD8+ T cell surface. The cytotoxic activity of antigen-experienced CD8+ T cells against the immunodominant trans-sialidase synthetic peptide IYNVGQVSI was decreased following active trans-sialidase- mediated resialylation in vitro and in vivo. Inhibition of the parasite's native trans-sialidase activity during infection strongly decreased CD8+ T cell sialylation, reverting it to the glycosylation status expected in the absence of parasite manipulation increasing mouse survival. Taken together, these results demonstrate, for the first time, that T. cruzi subverts sialylation to attenuate CD8+ T cell interactions with peptide-major histocompatibility complex class I complexes. CD8+ T cell resialylation may represent a sophisticated strategy to ensure lifetime host parasitism. PMID:20106975

  19. Non-responsiveness of antigen-experienced CD4 T cells reflects more stringent co-stimulatory requirements.

    PubMed Central

    Hamel, M E; Noteboom, E; Kruisbeek, A M

    1998-01-01

    We recently reported that previously activated T cells, irrespective of the nature of the first stimulus they encountered, are unable to respond to Staphylococcal enterotoxin B (SEB), nor to soluble anti-CD3 monoclonal antibody (mAb) presented by splenic antigen-presenting cells (APC). Such previously activated T cells are, however, fully capable of responding to plate-bound anti-CD3 plus splenic APC. These data suggest differential integration of the T-cell receptor (TCR) and co-stimulatory signalling pathways in naive versus antigen-experienced T cells. Consistent with this hypothesis, anti-CD28 mAb restores the proliferative capacity of resting ex vivo CD45RBlo CD4+ T cells (representing previously activated T cells) to both soluble anti-CD3 mAb and SEB. Interestingly, mAb-mediated engagement of cytotoxic T-lymphocyte antigen-4 (CTLA-4) completely negates the rescue effects mediated by anti-CD28 mAb in CD45RBlo cells. Nevertheless, the non-responsiveness of CD45RBlo CD4+ T cells cannot be reversed by anti-CTLA-4 Fab fragments, indicating that it is not related to negative regulatory effects of CTLA-4 engagement itself. Interestingly, the addition of interleukin-2 (IL-2) restores the proliferative capacity of CD45RBlo CD4+ T cells to SEB and soluble anti-CD3 mAb. Moreover, when rescued by IL-2, the cells are less susceptible to the negative regulatory effects of CTLA-4 engagement. Together, these findings suggest that the non-responsiveness of CD45RBlo CD4+ T cells to certain stimuli may be related to inadequate TCR signalling, primarily affecting IL-2 production. Images Figure 1 PMID:9640247

  20. Non-responsiveness of antigen-experienced CD4 T cells reflects more stringent co-stimulatory requirements.

    PubMed

    Hamel, M E; Noteboom, E; Kruisbeek, A M

    1998-03-01

    We recently reported that previously activated T cells, irrespective of the nature of the first stimulus they encountered, are unable to respond to Staphylococcal enterotoxin B (SEB), nor to soluble anti-CD3 monoclonal antibody (mAb) presented by splenic antigen-presenting cells (APC). Such previously activated T cells are, however, fully capable of responding to plate-bound anti-CD3 plus splenic APC. These data suggest differential integration of the T-cell receptor (TCR) and co-stimulatory signalling pathways in naive versus antigen-experienced T cells. Consistent with this hypothesis, anti-CD28 mAb restores the proliferative capacity of resting ex vivo CD45RBlo CD4+ T cells (representing previously activated T cells) to both soluble anti-CD3 mAb and SEB. Interestingly, mAb-mediated engagement of cytotoxic T-lymphocyte antigen-4 (CTLA-4) completely negates the rescue effects mediated by anti-CD28 mAb in CD45RBlo cells. Nevertheless, the non-responsiveness of CD45RBlo CD4+ T cells cannot be reversed by anti-CTLA-4 Fab fragments, indicating that it is not related to negative regulatory effects of CTLA-4 engagement itself. Interestingly, the addition of interleukin-2 (IL-2) restores the proliferative capacity of CD45RBlo CD4+ T cells to SEB and soluble anti-CD3 mAb. Moreover, when rescued by IL-2, the cells are less susceptible to the negative regulatory effects of CTLA-4 engagement. Together, these findings suggest that the non-responsiveness of CD45RBlo CD4+ T cells to certain stimuli may be related to inadequate TCR signalling, primarily affecting IL-2 production.

  1. Systemic Expression of Notch Ligand Delta-Like 4 during Mycobacterial Infection Alters the T Cell Immune Response

    PubMed Central

    Schaller, Matthew A.; Allen, Ronald M.; Kimura, Soichiro; Day, Cheryl L.; Kunkel, Steven L.

    2016-01-01

    The Notch ligand delta-like 4 (DLL4) is known to fine-tune the CD4+ T cell cytokine response. DLL4 is expressed on the surface of antigen-presenting cells (APCs) in a MyD88-dependent manner. We found that DLL4 expression was upregulated on bone marrow progenitor cells and APCs in mice infected with BCG Mycobacterium. Transfer of DLL4+ progenitor cells from infected hosts resulted in an increase DLL4+ myeloid cells in the spleen, indicating that expression of the dll4 gene is propagated throughout hematopoiesis. We also found an increase in DLL4+ monocytes from individuals who were infected with Mycobacterium tuberculosis. In latent individuals, DLL4 expression correlated with increased cytokine production from T cells in response to PPD stimulation. Finally, antibody blockade of DLL4 reduced T cell cytokine production from naïve T cells stimulated with antigen. These results demonstrate that the Notch ligand DLL4 can influence T cell cytokine production in both humans and mice, and further reveal that expression of DLL4 is upregulated on early hematopoietic progenitors in response to chronic mycobacterial infection. These data suggest that widespread DLL4 expression may occur as a result of mycobacterial infection, and that this expression may alter CD4+ T cell responses to both previously encountered and novel antigens. PMID:27933064

  2. Phenotypic and functional characterization of ex vivo T cell responses to the live attenuated herpes zoster vaccine.

    PubMed

    Patterson-Bartlett, Julie; Levin, Myron J; Lang, Nancy; Schödel, Florian P; Vessey, Rupert; Weinberg, Adriana

    2007-10-10

    To define the phenotypic characteristics and kinetics of T cell responses to a shingles vaccine in elderly individuals, 20 subjects > or =60 years of age received two doses of vaccine or placebo 6 weeks apart. VZV-specific T cell phenotypes and intracellular cytokines were determined by flow cytometry on blood mononuclear cells obtained pre-vaccination and up to 6 months after the second immunization. Results were compared with responses of five unvaccinated young adults. Pre-vaccination, elderly individuals had significantly lower VZV-specific effectors and cytokine-producing T cells compared with young adults. The vaccine significantly increased VZV-specific Th1, memory, early effector, and cutaneous homing receptor-bearing T cells.

  3. Myeloid-derived suppressor cells help protective immunity to Leishmania major infection despite suppressed T cell responses.

    PubMed

    Pereira, Wânia F; Ribeiro-Gomes, Flávia L; Guillermo, Landi V Costilla; Vellozo, Natália S; Montalvão, Fabrício; Dosreis, George A; Lopes, Marcela F

    2011-12-01

    Th1/Th2 cytokines play a key role in immune responses to Leishmania major by controlling macrophage activation for NO production and parasite killing. MDSCs, including myeloid precursors and immature monocytes, produce NO and suppress T cell responses in tumor immunity. We hypothesized that NO-producing MDSCs could help immunity to L. major infection. Gr1(hi)(Ly6C(hi)) CD11b(hi) MDSCs elicited by L. major infection suppressed polyclonal and antigen-specific T cell proliferation. Moreover, L. major-induced MDSCs killed intracellular parasites in a NO-dependent manner and reduced parasite burden in vivo. By contrast, treatment with ATRA, which induces MDSCs to differentiate into macrophages, increased development of lesions, parasite load, and T cell proliferation in draining LNs. Altogether, these results indicate that NO-producing MDSCs help protective immunity to L. major infection, despite suppressed T cell proliferation.

  4. Efficacy and toxicity management of CAR-T-cell immunotherapy: a matter of responsiveness control or tumour-specificity?

    PubMed

    Alonso-Camino, Vanesa; Harwood, Seandean Lykke; Álvarez-Méndez, Ana; Alvarez-Vallina, Luis

    2016-04-15

    Chimaeric antigen receptor (CAR)-expressing T-cells have demonstrated potent clinical efficacy in patients with haematological malignancies. However, the use of CAR-T-cells targeting solid tumour-associated antigens (TAAs) has been limited by organ toxicities related to activation of T-cell effector functions through the CAR. Most existing CARs recognize TAAs, which are also found in normal tissues. CAR-T-cell-mediated destruction of normal tissues constitutes a major roadblock to CAR-T-cell therapy, and must be avoided or mitigated. There is a broad range of strategies for modulating antigen responsiveness of CAR-T-cells, with varying degrees of complexity. Some of them might ameliorate the acute and chronic toxicities associated with current CAR constructs. However, further embellishments to CAR therapy may complicate clinical implementation and possibly create new immunogenicity issues. In contrast, the development of CARs targeting truly tumour-specific antigens might circumvent on-target/off-tumour toxicities without adding additional complexity to CAR-T-cell therapies, but these antigens have been elusive and may require novel selection strategies for their discovery.

  5. Infected Cell Protein (ICP)47 Enhances Herpes Simplex Virus Neurovirulence by Blocking the CD8+ T Cell Response

    PubMed Central

    Goldsmith, Kim; Chen, Wei; Johnson, David C.; Hendricks, Robert L.

    1998-01-01

    The herpes simplex virus (HSV) infected cell protein (ICP)47 blocks CD8+ T cell recognition of infected cells by inhibiting the transporter associated with antigen presentation (TAP). In vivo, HSV-1 replicates in two distinct tissues: in epithelial mucosa or epidermis, where the virus enters sensory neurons; and in the peripheral and central nervous system, where acute and subsequently latent infections occur. Here, we show that an HSV-1 ICP47− mutant is less neurovirulent than wild-type HSV-1 in mice, but replicates normally in epithelial tissues. The reduced neurovirulence of the ICP47− mutant was due to a protective CD8+ T cell response. When compared with wild-type virus, the ICP47− mutant expressed reduced neurovirulence in immunologically normal mice, and T cell–deficient nude mice after reconstitution with CD8+ T cells. However, the ICP47− mutant exhibited normal neurovirulence in mice that were acutely depleted of CD8+ T cells, and in nude mice that were not reconstituted, or were reconstituted with CD4+ T cells. In contrast, CD8+ T cell depletion did not increase the neurovirulence of an unrelated, attenuated HSV-1 glycoprotein (g)E− mutant. ICP47 is the first viral protein shown to influence neurovirulence by inhibiting CD8+ T cell protection. PMID:9449714

  6. Longitudinal PET imaging demonstrates biphasic CAR T cell responses in survivors

    PubMed Central

    Vedvyas, Yogindra; Shevlin, Enda; Zaman, Marjan; Min, Irene M.; Park, Spencer; Park, Susan; Kwon, Keon-Woo; Smith, Turner; Luo, Yonghua; Kim, Dohyun; Kim, Young; Law, Benedict; Ting, Richard; Jin, Moonsoo M.

    2016-01-01

    Clinical monitoring of adoptive T cell transfer (ACT) utilizes serial blood analyses to discern T cell activity. While useful, these data are 1-dimensional and lack spatiotemporal information related to treatment efficacy or toxicity. We utilized a human genetic reporter, somatostatin receptor 2 (SSTR2), and PET, to quantitatively and longitudinally visualize whole-body T cell distribution and antitumor dynamics using a clinically approved radiotracer. Initial evaluations determined that SSTR2-expressing T cells were detectable at low densities with high sensitivity and specificity. SSTR2-based PET was applied to ACT of chimeric antigen receptor (CAR) T cells targeting intercellular adhesion molecule-1, which is overexpressed in anaplastic thyroid tumors. Timely CAR T cell infusions resulted in survival of tumor-bearing mice, while later infusions led to uniform death. Real-time PET imaging revealed biphasic T cell expansion and contraction at tumor sites among survivors, with peak tumor burden preceding peak T cell burden by several days. In contrast, nonsurvivors displayed unrelenting increases in tumor and T cell burden, indicating that tumor growth was outpacing T cell killing. Thus, longitudinal PET imaging of SSTR2-positive ACT dynamics enables prognostic, spatiotemporal monitoring with unprecedented clarity and detail to facilitate comprehensive therapy evaluation with potential for clinical translation. PMID:27882353

  7. T-cell motility in the early stages of the immune response modeled as a random walk amongst targets

    NASA Astrophysics Data System (ADS)

    Preston, S. P.; Waters, S. L.; Jensen, O. E.; Heaton, P. R.; Pritchard, D. I.

    2006-07-01

    The transport process by which a T cell makes high-frequency encounters with antigen-presenting cells following infection is an important element of adaptive immunity. Recent experimental work has allowed in vivo cell motility to be characterized in detail. On the basis of experimental data we develop a quantitative model for encounters between T cells and antigen-presenting cells. We model this as a transport-limited chemical reaction with the dynamics dependent on physical contact between randomly moving reactants. We use asymptotic methods to calculate a time distribution which characterizes the delay before a T cell is activated and use Monte Carlo simulations to verify the analysis. We find that the density of antigen-primed dendritic cells within the lymph node paracortex must be greater than 35cells/mm3 for a T cell to have a more than 50% chance of encountering a dendritic cell within 24h . This density is much larger than existing estimates based on calculations which neglect the transport process. We also use simulations to compare a T cell which re-orients isotropically with a T cell which turns according to an experimentally observed distribution and find that the effects of anisotropy on the solution are small.

  8. PI3Kδ Regulates the Magnitude of CD8+ T Cell Responses after Challenge with Listeria monocytogenes

    PubMed Central

    Pearce, Verity Q.; Bouabe, Hicham; MacQueen, Amy R.; Carbonaro, Valentina

    2015-01-01

    PI3Ks regulate diverse immune cell functions by transmitting intracellular signals from Ag, costimulatory receptors, and cytokine receptors to control cell division, differentiation, survival, and migration. In this study, we report the effect of inhibiting the p110δ subunit of PI3Kδ on CD8+ T cell responses to infection with the intracellular bacteria Listeria monocytogenes. A strong dependency on PI3Kδ for IFN-γ production by CD8+ T cells in vitro was not recapitulated after Listeria infection in vivo. Inactivation of PI3Kδ resulted in enhanced bacterial elimination by the innate immune system. However, the magnitudes of the primary and secondary CD8+ T cell responses were reduced. Moreover, PI3Kδ activity was required for CD8+ T cells to provide help to other responding CD8+ cells. These findings identify PI3Kδ as a key regulator of CD8+ T cell responses that integrates extrinsic cues, including those from other responding cells, to determine the collective behavior of CD8+ T cell populations responding to infection. PMID:26311905

  9. Mathematical model reveals how regulating the three phases of T-cell response could counteract immune evasion

    PubMed Central

    Lorenzi, Tommaso; Chisholm, Rebecca H; Melensi, Matteo; Lorz, Alexander; Delitala, Marcello

    2015-01-01

    T cells are key players in immune action against the invasion of target cells expressing non-self antigens. During an immune response, antigen-specific T cells dynamically sculpt the antigenic distribution of target cells, and target cells concurrently shape the host’s repertoire of antigen-specific T cells. The succession of these reciprocal selective sweeps can result in ‘chase-and-escape’ dynamics and lead to immune evasion. It has been proposed that immune evasion can be countered by immunotherapy strategies aimed at regulating the three phases of the immune response orchestrated by antigen-specific T cells: expansion, contraction and memory. Here, we test this hypothesis with a mathematical model that considers the immune response as a selection contest between T cells and target cells. The outcomes of our model suggest that shortening the duration of the contraction phase and stabilizing as many T cells as possible inside the long-lived memory reservoir, using dual immunotherapies based on the cytokines interleukin-7 and/or interleukin-15 in combination with molecular factors that can keep the immunomodulatory action of these interleukins under control, should be an important focus of future immunotherapy research. PMID:26119966

  10. High-throughput monitoring of human tumor-specific T-cell responses with large peptide pools

    PubMed Central

    Chevalier, Mathieu F; Bobisse, Sara; Costa-Nunes, Carla; Cesson, Valérie; Jichlinski, Patrice; Speiser, Daniel E; Harari, Alexandre; Coukos, George; Romero, Pedro; Nardelli-Haefliger, Denise; Jandus, Camilla; Derré, Laurent

    2015-01-01

    In immune intervention trials, the comprehensive investigation of immunogenicity or T-cell epitope-mapping is challenging especially when a large set of epitopes needs to be screened and limited sample material is available. To this end, T-cell responses are often monitored using peptide pools. Here, we assessed the magnitude and sensitivity of detection of antigen-specific CD8+ and CD4+ T cells using a single peptide alone or mixed into large pools. Interestingly the magnitude of ex vivo anti-viral and anti-tumor T-cell responses was identical irrespective of the presence and number of irrelevant peptides, in different functional assays with PBMCs from healthy donors and cancer patients. Moreover, the presence of up to 300 irrelevant peptides did not affect the threshold of responsiveness of antigen-specific CD8+ T cells to single cognate peptides. These data demonstrate the relevance of using very large peptide pools for the sensitive and specific immune-monitoring of epitope-specific T cells in natural or immune-modulated context. PMID:26451296

  11. Dynamic changes in circulating and antigen-responsive T-cell subpopulations post-Mycobacterium bovis infection in cattle.

    PubMed Central

    Pollock, J M; Pollock, D A; Campbell, D G; Girvin, R M; Crockard, A D; Neill, S D; Mackie, D P

    1996-01-01

    Bovine tuberculosis is a threat to animal and human health in several countries. Greater understanding of the immunology of the disease is required to develop improved tests and vaccines. This study has used a model of bovine tuberculosis, established in the natural host, to investigate the dynamic changes that occur in the circulating T-cell subpopulations after infection. When the phenotypic composition of the peripheral blood lymphocytes was determined pre- and post-experimental infection, the response to disease comprised three phases. Firstly, the WC1/gamma delta T cells decreased and then increased, suggesting localization to developing lesions and clonal expansion. Secondly, the CD4:CD8 ratio increased. Thirdly, the CD4:CD8 ratio decreased to less than pre-infection measurements. The latter changes suggested sequential involvement of CD4 and then CD8 T cells. The proportion of cells expressing interleukin-2 receptor (IL-2R) also increased. Panels of T-cell clones were established at various stages post-infection and all clones that exhibited antigen responsiveness were phenotyped. T-cell clones from early infection were WC1/gamma delta and CD4 in phenotype, while CD8 clones appeared later in infection, eventually becoming dominant. Therefore, from in vivo and in vitro evidence, it was suggested that there is a dynamic progression in the T-cell subpopulations involved dominantly in responses to mycobacteria. PMID:8698385

  12. Mathematical model reveals how regulating the three phases of T-cell response could counteract immune evasion.

    PubMed

    Lorenzi, Tommaso; Chisholm, Rebecca H; Melensi, Matteo; Lorz, Alexander; Delitala, Marcello

    2015-10-01

    T cells are key players in immune action against the invasion of target cells expressing non-self antigens. During an immune response, antigen-specific T cells dynamically sculpt the antigenic distribution of target cells, and target cells concurrently shape the host's repertoire of antigen-specific T cells. The succession of these reciprocal selective sweeps can result in 'chase-and-escape' dynamics and lead to immune evasion. It has been proposed that immune evasion can be countered by immunotherapy strategies aimed at regulating the three phases of the immune response orchestrated by antigen-specific T cells: expansion, contraction and memory. Here, we test this hypothesis with a mathematical model that considers the immune response as a selection contest between T cells and target cells. The outcomes of our model suggest that shortening the duration of the contraction phase and stabilizing as many T cells as possible inside the long-lived memory reservoir, using dual immunotherapies based on the cytokines interleukin-7 and/or interleukin-15 in combination with molecular factors that can keep the immunomodulatory action of these interleukins under control, should be an important focus of future immunotherapy research.

  13. Airway responses towards allergens - from the airway epithelium to T cells.

    PubMed

    Papazian, D; Hansen, S; Würtzen, P A

    2015-08-01

    The prevalence of allergic diseases such as allergic rhinitis is increasing, affecting up to 30% of the human population worldwide. Allergic sensitization arises from complex interactions between environmental exposures and genetic susceptibility, resulting in inflammatory T helper 2 (Th2) cell-derived immune responses towards environmental allergens. Emerging evidence now suggests that an epithelial dysfunction, coupled with inherent properties of environmental allergens, can be responsible for the inflammatory responses towards allergens. Several epithelial-derived cytokines, such as thymic stromal lymphopoietin (TSLP), IL-25 and IL-33, influence tissue-resident dendritic cells (DCs) as well as Th2 effector cells. Exposure to environmental allergens does not elicit Th2 inflammatory responses or any clinical symptoms in nonatopic individuals, and recent findings suggest that a nondamaged, healthy epithelium lowers the DCs' ability to induce inflammatory T-cell responses towards allergens. The purpose of this review was to summarize the current knowledge on which signals from the airway epithelium, from first contact with inhaled allergens all the way to the ensuing Th2-cell responses, influence the pathology of allergic diseases.

  14. CD4 T-Cell Responses in Primary HIV Infection: Interrelationship with Immune Activation and Virus Burden

    PubMed Central

    Chevalier, Mathieu F.; Didier, Céline; Girard, Pierre-Marie; Manea, Maria E.; Campa, Pauline; Barré-Sinoussi, Françoise; Scott-Algara, Daniel; Weiss, Laurence

    2016-01-01

    Early events during primary HIV infection (PHI) are thought to influence disease outcome. Although a growing body of evidence suggests a beneficial role of HIV-specific CD4 help in HIV infection, it is unclear how early viral replication, systemic immune activation, and antiretroviral therapy (ART) may shape CD4 T-cell responses during PHI, and whether HIV-specific CD4 responses contribute to the high immune activation observed in PHI. Twenty-seven patients with early PHI were included in a prospective longitudinal study and 12 of them received ART after enrollment. Fresh peripheral blood mononuclear cells were used for measurement of ex vivo T-cell activation and of cytokine-producing CD4 T-cells following stimulation with PMA/ionomycin or HIV-1-gag-p24 antigen. Patients were segregated based on CD8 T-cell activation level (i.e., % HLA-DR+CD38+ CD8 T-cells) at baseline (BL). Patients with lower immune activation exhibited higher frequency of bulk CD4 T-cells producing IFN-γ or IL-17 and higher effector-to-regulatory cell ratios. No differences were found in HIV-specific CD4 T-cell frequencies. In contrast, segregation of patients based on plasma viral load (pVL) revealed that patients with higher pVL showed higher cytokine-producing HIV-specific CD4 responses. Of note, the frequency of IFN-γ+ HIV-specific CD4 T cells significantly diminished between BL and month 6 only in ART-treated patients. However, early treatment initiation was associated with better maintenance of HIV-specific IFN-γ+ CD4 T-cells. These data suggest that HIV-specific CD4 responses do not fuel systemic T-cell activation and are driven by viral replication but not able to contribute to its control in the early phase of infection. Moreover, our data also suggest a benefit of early treatment for the maintenance of HIV-specific CD4 T-cell help. PMID:27746782

  15. Type I interferon suppresses virus-specific B cell responses by modulating CD8+ T cell differentiation

    PubMed Central

    Moseman, E. Ashley; Wu, Tuoqi; de la Torre, Juan Carlos; Schwartzberg, Pamela L.; McGavern, Dorian B.

    2016-01-01

    Studies have established a role for T cells in resolving persistent viral infections, yet emerging evidence indicates that both T and B cells are required to control some viruses. During persistent infection, a marked lag or failure to generate neutralizing antibodies is commonly observed and likely contributes to an inability to control certain pathogens. Using lymphocytic choriomeningitis virus (LCMV) as a model, we have examined how a persistent viral infection can suppress neutralizing humoral immunity. By tracking the fate of virus-specific B cells in vivo, we report that LCMV-specific B cells were rapidly deleted within a few days of persistent infection, and this deletion was completely reversed by blockade of type I interferon (IFN-I) signaling. Early interference with IFN-I signaling promoted survival and differentiation of LCMV-specific B cells, which accelerated the generation of neutralizing antibodies. This marked improvement in antiviral humoral immunity did not rely on the cessation of IFN-I signaling in B cells but on alterations in the virus-specific CD8+ T cell response. Using two-photon microscopy and in vivo calcium imaging, we observed that cytotoxic T lymphocytes (CTLs) productively engaged and killed LCMV-specific B cells in a perforin-dependent manner within the first few days of infection. Blockade of IFN-I signaling protected LCMV-specific B cells by promoting CTL dysfunction. Therapeutic manipulation of this pathway may facilitate efforts to promote humoral immunity during persistent viral infection in humans. Our findings illustrate how events that occur early after infection can disturb the resultant adaptive response and contribute to viral persistence. PMID:27812556

  16. CD4+ T cells are important mediators of oxidative stress that cause hypertension in response to placental ischemia.

    PubMed

    Wallace, Kedra; Cornelius, Denise C; Scott, Jeremy; Heath, Judith; Moseley, Janae; Chatman, Krystal; LaMarca, Babbette

    2014-11-01

    Preeclampsia is associated with oxidative stress, which is suspected to play a role in hypertension, placental ischemia, and fetal demise associated with the disease. Various cellular sources of oxidative stress, such as neutrophils, monocytes, and CD4(+) T cells have been suggested as culprits in the pathophysiology of preeclampsia. The objective of this study was to examine a role of circulating and placental CD4(+) T cells in oxidative stress in response to placental ischemia during pregnancy. CD4(+) T cells and oxidative stress were measured in preeclamptic and normal pregnant women, placental ischemic and normal pregnant rats, and normal pregnant recipient rats of placental ischemic CD4(+) T cells. Women with preeclampsia had significantly increased circulating (P=0.02) and placental CD4(+) T cells (P=0.0001); lymphocyte secretion of myeloperoxidase (P=0.004); and placental reactive oxygen species (P=0.0004) when compared with normal pregnant women. CD4(+) T cells from placental ischemic rats cause many facets of preeclampsia when injected into normal pregnant recipient rats on gestational day 13. On gestational day 19, blood pressure increased in normal pregnant recipients of placental ischemic CD4(+) T cells (P=0.002) compared with that in normal pregnant rats. Similar to preeclamptic patients, CD4(+) T cells from placental ischemic rats secreted significantly more myeloperoxidase (P=0.003) and induced oxidative stress in cultured vascular cells (P=0.003) than normal pregnant rat CD4(+)Tcells. Apocynin, a nicotinamide adenine dinucleotide phosphate inhibitor, attenuated hypertension and all oxidative stress markers in placental ischemic and normal pregnant recipient rats of placental ischemic CD4(+)Tcells (P=0.05). These data demonstrate an important role for CD4(+) T cells in mediating another factor, oxidative stress, to cause hypertension during preeclampsia.

  17. Cyclin-dependent kinase 5 activity is required for allogeneic T-cell responses after hematopoietic cell transplantation in mice

    PubMed Central

    Pareek, Tej K.; Eid, Saada; Ganguly, Sudipto; Tyler, Megan; Huang, Alex Y.; Letterio, John J.

    2017-01-01

    Molecular intermediates in T-cell activation pathways are crucial targets for the therapy and prevention of graft-versus-host disease (GVHD) following allogeneic hematopoietic cell transplantation (allo-HCT). We recently identified an essential role for cyclin-dependent kinase 5 (Cdk5) in T-cell activation and effector function, but the contribution of Cdk5 activity to the development of GVHD has not been explored. Using an established, preclinical, murine, GVHD model, we reveal that Cdk5 activity is increased in key target organs early after allo-HCT. We then generated chimeric mice (Cdk5+/+C or Cdk5−/−C) using hematopoietic progenitors from either embryonic day 16.5 Cdk5+/+ or Cdk5−/− embryos to enable analyses of the role of Cdk5 in GVHD, as germ line Cdk5 gene deletion is embryonically lethal. The immunophenotype of adult Cdk5−/−C mice is identical to control Cdk5+/+C mice. However, transplantation of donor Cdk5−/−C bone marrow and T cells dramatically reduced the severity of systemic and target organ GVHD. This phenotype is attributed to decreased T-cell migration to secondary lymphoid organs (SLOs), reduced in vivo proliferation within these organs, and fewer cytokine-producing donor T cells during GVHD development. Moreover, these defects in Cdk5−/− T-cell function are associated with altered CCR7 signaling following ligation by CCL19, a receptor:ligand interaction critical for T-cell migration into SLOs. Although Cdk5 activity in donor T cells contributed to graft-versus-tumor effects, pharmacologic inhibition of Cdk5 preserved leukemia-free survival. Collectively, our data implicate Cdk5 in allogeneic T-cell responses after HCT and as an important new target for therapeutic intervention. PMID:28064242

  18. Regulatory B and T cell responses in patients with autoimmune thyroid disease and healthy controls.

    PubMed

    Kristensen, Birte

    2016-02-01

    Autoimmune diseases occur due to faulty self-tolerance. Graves' disease (GD) and Hashimoto's thyroiditis (HT) are classic examples of organ-specific autoimmune diseases. GD is an auto-antibody-mediated disease where autoantibodies are produced against the thyroid stimulating hormone receptor (TSHR). HT is primarily a T-cell mediated disease, and whether B cells play a pathogenic role in the pathogenesis is still unclear. Both GD and HT are characterized by infiltration of the thyroid gland by self-reactive T cells and B cells. In the first paper of this thesis, the role of regulatory B cells (Bregs) and regulatory T cells (Tregs) were investigated in the context of GD and HT. First, we studied the role of the thyroid self-antigen, thyroglobulin (TG) in healthy donors. The self-antigen TG, but not the foreign recall antigen tetanus toxoid (TT), was able to induce interleukin 10 (IL-10) secretion by B cells and CD4+ T cells. These IL-10 producing B cells (B10 cells) from healthy donors were enriched with the CD5+ and CD24hi phenotype. In addition, TG was able to induce IL-6 production by B cells. In contrast, TT induced production of Th1-type pro-inflammatory cytokines including interferon-gamma (IFN-γ) and IL-2. In the second paper, the frequency and phenotype of B10 was investigated in healthy donors and patients with GD or HT.  The frequencies of B10 cells were similar in the three groups, irrespective of whether IL-10 was induced by a combination of phorbol 12-myristate 13-acetate (PMA) and ionomycin, by CpG oligodeoxynucletodies (ODN) 2006, or by TG. Several phenotypes have been associated with B10 cells such as CD5+, CD25+, TIM-1+, CD24hiCD38hi and CD27+CD43+. We found that larger proportions of B10 cells in patients with GD or HT were CD25+ and TIM-1+ than B10 cells in healthy donors. In healthy donors, B10 cells were CD24hiCD38-, whereas for HT patients these cells were primarily CD24intCD38int. For GD patients, we found lower proportions of B10 cells

  19. Persistence of T-cell immune response induced by two acellular pertussis vaccines in children five years after primary vaccination.

    PubMed

    Palazzo, Raffaella; Carollo, Maria; Bianco, Manuela; Fedele, Giorgio; Schiavoni, Ilaria; Pandolfi, Elisabetta; Villani, Alberto; Tozzi, Alberto E; Mascart, Françoise; Ausiello, Clara M

    2016-01-01

    The resurgence of pertussis suggests the need for greater efforts to understand the long-lasting protective responses induced by vaccination. In this paper we dissect the persistence of T memory responses induced by primary vaccination with two different acellular pertussis (aP) vaccines, hexavalent Hexavac® vaccine (Hexavac) (Sanofi Pasteur MSD) and Infanrix hexa® (Infanrix) (Glaxo-SmithKline Biologicals). We evaluated magnitude and duration of T-cell responses to pertussis toxin (PT) by measuring T-cell proliferation, cytokines (IL-2 and IFNγ) production and memory subsets in two groups of children 5 years after primary vaccination. Some of the enrolled children received only primary vaccination, while others had the pre-school boost dose. Positive T-cell responses to PT were detected in 36% of children. Percentage of responsive children, T-cell proliferation and CD4IL-2+ cells were significantly higher in the children primed with Hexavac than in those who received Infanrix vaccine. No major effects of the boost on PT-specific proliferation were observed. Overall, our data documented a persistence of T-cell memory against PT in a minor fraction of children 5 years after primary vaccination. The different responses induced by Hexavac and Infanrix vaccine could rely on differences in PT inactivation process or excipients/adjuvants formulations.

  20. Barcoding T Cell Calcium Response Diversity with Methods for Automated and Accurate Analysis of Cell Signals (MAAACS)

    PubMed Central

    Sergé, Arnauld; Bernard, Anne-Marie; Phélipot, Marie-Claire; Bertaux, Nicolas; Fallet, Mathieu; Grenot, Pierre; Marguet, Didier; He, Hai-Tao; Hamon, Yannick

    2013-01-01

    We introduce a series of experimental procedures enabling sensitive calcium monitoring in T cell populations by confocal video-microscopy. Tracking and post-acquisition analysis was performed using Methods for Automated and Accurate Analysis of Cell Signals (MAAACS), a fully customized program that associates a high throughput tracking algorithm, an intuitive reconnection routine and a statistical platform to provide, at a glance, the calcium barcode of a population of individual T-cells. Combined with a sensitive calcium probe, this method allowed us to unravel the heterogeneity in shape and intensity of the calcium response in T cell populations and especially in naive T cells, which display intracellular calcium oscillations upon stimulation by antigen presenting cells. PMID:24086124

  1. The effect of adenovirus-specific antibodies on adenoviral vector–induced, transgene product–specific T cell responses

    PubMed Central

    Small, Juliana C.; Haut, Larissa H.; Bian, Ang; Ertl, Hildegund C. J.

    2014-01-01

    In this study, we tested the effect of neutralizing Abs to different serotypes of E1-deleted Ad vectors on the immunogenicity of the homologous Ad vector or a vector derived from a heterologous serotype. Our results showed that, as expected, even low titers of passively transferred neutralizing Abs significantly reduced the homologous vectors' ability to elicit transgene-specific CD8+ T cell responses. In addition, Abs changed the fate of transgene product–specific CD8+ T cells by promoting their transition into the central memory cell pool, which resulted in markedly enhanced expansion of transgene product–specific CD8+ T cells after a boost with a heterologous Ad vector. Non-neutralizing Abs specific to a distinct Ad serotype had no effect on the magnitude of transgene product-specific CD8+ T cells induced by a heterologous Ad vector, nor did such Abs promote induction of more resting memory CD8+ T cells. These results show that Abs to an Ad vaccine carrier affect not only the magnitude but also the profile of a vector-induced CD8+ T cell response. PMID:25082150

  2. Modulation of CD8+ T cell responses to AAV vectors with IgG-derived MHC class II epitopes.

    PubMed

    Hui, Daniel J; Basner-Tschakarjan, Etiena; Chen, Yifeng; Davidson, Robert J; Buchlis, George; Yazicioglu, Mustafa; Pien, Gary C; Finn, Jonathan D; Haurigot, Virginia; Tai, Alex; Scott, David W; Cousens, Leslie P; Zhou, Shangzhen; De Groot, Anne S; Mingozzi, Federico

    2013-09-01

    Immune responses directed against viral capsid proteins constitute a main safety concern in the use of adeno-associated virus (AAV) as gene transfer vectors in humans. Pharmacological immunosuppression has been proposed as a solution to the problem; however, the approach suffers from several potential limitations. Using MHC class II epitopes initially identified within human IgG, named Tregitopes, we showed that it is possible to modulate CD8+ T cell responses to several viral antigens in vitro. We showed that incubation of peripheral blood mononuclear cells with these epitopes triggers proliferation of CD4+CD25+FoxP3+ T cells that suppress killing of target cells loaded with MHC class I antigens in an antigen-specific fashion, through a mechanism that seems to require cell-to-cell contact. Expression of a construct encoding for the AAV capsid structural protein fused to Tregitopes resulted in reduction of CD8+ T cell reactivity against the AAV capsid following immunization with an adenoviral vector expressing capsid. This was accompanied by an increase in frequency of CD4+CD25+FoxP3+ T cells in spleens and lower levels of inflammatory infiltrates in injected tissues. This proof-of-concept study demonstrates modulation of CD8+ T cell reactivity to an antigen using regulatory T cell epitopes is possible.

  3. Loss of NOX-Derived Superoxide Exacerbates Diabetogenic CD4 T-Cell Effector Responses in Type 1 Diabetes.

    PubMed

    Padgett, Lindsey E; Anderson, Brian; Liu, Chao; Ganini, Douglas; Mason, Ronald P; Piganelli, Jon D; Mathews, Clayton E; Tse, Hubert M

    2015-12-01

    Reactive oxygen species (ROS) play prominent roles in numerous biological systems. While classically expressed by neutrophils and macrophages, CD4 T cells also express NADPH oxidase (NOX), the superoxide-generating multisubunit enzyme. Our laboratory recently demonstrated that superoxide-deficient nonobese diabetic (NOD.Ncf1(m1J)) mice exhibited a delay in type 1 diabetes (T1D) partially due to blunted IFN-γ synthesis by CD4 T cells. For further investigation of the roles of superoxide on CD4 T-cell diabetogenicity, the NOD.BDC-2.5.Ncf1(m1J) (BDC-2.5.Ncf1(m1J)) mouse strain was generated, possessing autoreactive CD4 T cells deficient in NOX-derived superoxide. Unlike NOD.Ncf1(m1J), stimulated BDC-2.5.Ncf1(m1J) CD4 T cells and splenocytes displayed elevated synthesis of Th1 cytokines and chemokines. Superoxide-deficient BDC-2.5 mice developed spontaneous T1D, and CD4 T cells were more diabetogenic upon adoptive transfer into NOD.Rag recipients due to a skewing toward impaired Treg suppression. Exogenous superoxide blunted exacerbated Th1 cytokines and proinflammatory chemokines to approximately wild-type levels, concomitant with reduced IL-12Rβ2 signaling and P-STAT4 (Y693) activation. These results highlight the importance of NOX-derived superoxide in curbing autoreactivity due, in part, to control of Treg function and as a redox-dependent checkpoint of effector T-cell responses. Ultimately, our studies reveal the complexities of free radicals in CD4 T-cell responses.

  4. Human neutrophil clearance of bacterial pathogens triggers anti-microbial γδ T cell responses in early infection.

    PubMed

    Davey, Martin S; Lin, Chan-Yu; Roberts, Gareth W; Heuston, Sinéad; Brown, Amanda C; Chess, James A; Toleman, Mark A; Gahan, Cormac G M; Hill, Colin; Parish, Tanya; Williams, John D; Davies, Simon J; Johnson, David W; Topley, Nicholas; Moser, Bernhard; Eberl, Matthias

    2011-05-01

    Human blood Vγ9/Vδ2 T cells, monocytes and neutrophils share a responsiveness toward inflammatory chemokines and are rapidly recruited to sites of infection. Studying their interaction in vitro and relating these findings to in vivo observations in patients may therefore provide crucial insight into inflammatory events. Our present data demonstrate that Vγ9/Vδ2 T cells provide potent survival signals resulting in neutrophil activation and the release of the neutrophil chemoattractant CXCL8 (IL-8). In turn, Vγ9/Vδ2 T cells readily respond to neutrophils harboring phagocytosed bacteria, as evidenced by expression of CD69, interferon (IFN)-γ and tumor necrosis factor (TNF)-α. This response is dependent on the ability of these bacteria to produce the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), requires cell-cell contact of Vγ9/Vδ2 T cells with accessory monocytes through lymphocyte function-associated antigen-1 (LFA-1), and results in a TNF-α dependent proliferation of Vγ9/Vδ2 T cells. The antibiotic fosmidomycin, which targets the HMB-PP biosynthesis pathway, not only has a direct antibacterial effect on most HMB-PP producing bacteria but also possesses rapid anti-inflammatory properties by inhibiting γδ T cell responses in vitro. Patients with acute peritoneal-dialysis (PD)-associated bacterial peritonitis--characterized by an excessive influx of neutrophils and monocytes into the peritoneal cavity--show a selective activation of local Vγ9/Vδ2 T cells by HMB-PP producing but not by HMB-PP deficient bacterial pathogens. The γδ T cell-driven perpetuation of inflammatory responses during acute peritonitis is associated with elevated peritoneal levels of γδ T cells and TNF-α and detrimental clinical outcomes in infections caused by HMB-PP positive microorganisms. Taken together, our findings indicate a direct link between invading pathogens, neutrophils, monocytes and microbe-responsive γδ T cells in early

  5. Elicitation of T-cell responses by structural and non-structural proteins of coxsackievirus B4.

    PubMed

    Bengs, Suvi; Marttila, Jane; Susi, Petri; Ilonen, Jorma

    2015-02-01

    Coxsackievirus B4 (CV-B4) belongs to the genus Enterovirus within the family Picornaviridae. To investigate target proteins recognized by T-cells in human enterovirus B infections, virus-encoded structural [VP0 (VP4 and VP2), VP1, VP3] and non-structural (2A, 2B, 2C, 3C and 3D) proteins were expressed and purified in Escherichia coli. Peripheral blood of 19 healthy adult donors was used to create enterovirus-specific T-cell lines by repeated stimulation with CV-B4 cell lysate antigen. T-cell lines responded in individual patterns, and responses to all purified proteins were observed. The most often recognized enteroviral protein was VP0, which is the fusion between the most conserved structural proteins, VP4 and VP2. T-cell responses to VP0 were detected in 15 of the 19 (79 %) donor lines. Non-structural 2C protein was recognized in 11 of the 19 (58 %) lines, and 11 of the 19 (58 %) lines also had a response to 3D protein. Furthermore, responses to other non-structural proteins (2A, 2B and 3C) were also detected. T-cell responses did not correlate clearly to the individual HLA-DR-DQ phenotype or the history of past coxsackie B virus infections of the donors.

  6. The adaptive immune response in celiac disease.

    PubMed

    Qiao, Shuo-Wang; Iversen, Rasmus; Ráki, Melinda; Sollid, Ludvig M

    2012-07-01

    Compared to other human leukocyte antigen (HLA)-associated diseases such as type 1 diabetes, multiple sclerosis, and rheumatoid arthritis, fundamental aspects of the pathogenesis in celiac disease are relatively well understood. This is mostly because the causative antigen in celiac disease-cereal gluten proteins-is known and the culprit HLA molecules are well defined. This has facilitated the dissection of the disease-relevant CD4+ T cells interacting with the disease-associated HLA molecules. In addition, celiac disease has distinct antibody responses to gluten and the autoantigen transglutaminase 2, which give strong handles to understand all sides of the adaptive immune response leading to disease. Here we review recent developments in the understanding of the role of T cells, B cells, and antigen-presenting cells in the pathogenic immune response of this instructive disorder.

  7. Plasmacytoid DC from Aged Mice Down-Regulate CD8 T Cell Responses by Inhibiting cDC Maturation after Encephalitozoon cuniculi Infection

    PubMed Central

    Gigley, Jason P.; Khan, Imtiaz A.

    2011-01-01

    Age associated impairment of immune function results in inefficient vaccination, tumor surveillance and increased severity of infections. Several alterations in adaptive immunity have been observed and recent studies report age related declines in innate immune responses to opportunistic pathogens including Encephalitozoon cuniculi. We previously demonstrated that conventional dendritic cells (cDC) from 9-month-old animals exhibit sub-optimal response to E. cuniculi infection, suggesting that age associated immune senescence begins earlier than expected. We focused this study on how age affects plasmacytoid DC (pDC) function. More specifically how aged pDC affect cDC function as we observed that the latter are the predominant activators of CD8 T cells during this infection. Our present study demonstrates that pDC from middle-aged mice (12 months) suppress young (8 week old) cDC driven CD8 T cell priming against E. cuniculi infection. The suppressive effect of pDC from older mice decreased maturation of young cDC via cell contact. Aged mouse pDC exhibited higher expression of PD-L1 and blockade of their interaction with cDC via this molecule restored cDC maturation and T cell priming. Furthermore, the PD-L1 dependent suppression of cDC T cell priming was restricted to effector function of antigen-specific CD8 T cells not their expansion. To the best of our knowledge, the data presented here is the first report highlighting a cell contact dependent, PD-L1 regulated, age associated defect in a DC subpopulation that results in a sub-optimal immune response against E. cuniculi infection. These results have broad implications for design of immunotherapeutic approaches to enhance immunity for aging populations. PMID:21695169

  8. Plasmacytoid DC from aged mice down-regulate CD8 T cell responses by inhibiting cDC maturation after Encephalitozoon cuniculi infection.

    PubMed

    Gigley, Jason P; Khan, Imtiaz A

    2011-01-01

    Age associated impairment of immune function results in inefficient vaccination, tumor surveillance and increased severity of infections. Several alterations in adaptive immunity have been observed and recent studies report age related declines in innate immune responses to opportunistic pathogens including Encephalitozoon cuniculi. We previously demonstrated that conventional dendritic cells (cDC) from 9-month-old animals exhibit sub-optimal response to E. cuniculi infection, suggesting that age associated immune senescence begins earlier than expected. We focused this study on how age affects plasmacytoid DC (pDC) function. More specifically how aged pDC affect cDC function as we observed that the latter are the predominant activators of CD8 T cells during this infection. Our present study demonstrates that pDC from middle-aged mice (12 months) suppress young (8 week old) cDC driven CD8 T cell priming against E. cuniculi infection. The suppressive effect of pDC from older mice decreased maturation of young cDC via cell contact. Aged mouse pDC exhibited higher expression of PD-L1 and blockade of their interaction with cDC via this molecule restored cDC maturation and T cell priming. Furthermore, the PD-L1 dependent suppression of cDC T cell priming was restricted to effector function of antigen-specific CD8 T cells not their expansion. To the best of our knowledge, the data presented here is the first report highlighting a cell contact dependent, PD-L1 regulated, age associated defect in a DC subpopulation that results in a sub-optimal immune response against E. cuniculi infection. These results have broad implications for design of immunotherapeutic approaches to enhance immunity for aging populations.

  9. Specificity and Dynamics of Effector and Memory CD8 T Cell Responses in Human Tick-Borne Encephalitis Virus Infection

    PubMed Central

    Blom, Kim; Braun, Monika; Pakalniene, Jolita; Dailidyte, Laura; Béziat, Vivien; Lampen, Margit H.; Klingström, Jonas; Lagerqvist, Nina; Kjerstadius, Torbjörn; Michaëlsson, Jakob; Lindquist, Lars; Ljunggren, Hans-Gustaf; Sandberg, Johan K.; Mickiene, Aukse; Gredmark-Russ, Sara

    2015-01-01

    Tick-borne encephalitis virus (TBEV) is transferred to humans by ticks. The virus causes tick-borne encephalitis (TBE) with symptoms such as meningitis and meningoencephalitis. About one third of the patients suffer from long-lasting sequelae after clearance of the infection. Studies of the immune response during TBEV-infection are essential to the understanding of host responses to TBEV-infection and for the development of therapeutics. Here, we studied in detail the primary CD8 T cell response to TBEV in patients with acute TBE. Peripheral blood CD8 T cells mounted a considerable response to TBEV-infection as assessed by Ki67 and CD38 co-expression. These activated cells showed a CD45RA-CCR7-CD127- phenotype at day 7 after hospitalization, phenotypically defining them as effector cells. An immunodominant HLA-A2-restricted TBEV epitope was identified and utilized to study the characteristics and temporal dynamics of the antigen-specific response. The functional profile of TBEV-specific CD8 T cells was dominated by variants of mono-functional cells as the effector response matured. Antigen-specific CD8 T cells predominantly displayed a distinct Eomes+Ki67+T-bet+ effector phenotype at the peak of the response, which transitioned to an Eomes-Ki67-T-bet+ phenotype as the infection resolved and memory was established. These transcription factors thus characterize and discriminate stages of the antigen-specific T cell response during acute TBEV-infection. Altogether, CD8 T cells responded strongly to acute TBEV infection and passed through an effector phase, prior to gradual differentiation into memory cells with distinct transcription factor expression-patterns throughout the different phases. PMID:25611738

  10. Reactive Oxygen Species Regulate T Cell Immune Response in the Tumor Microenvironment

    PubMed Central

    Chen, Xinfeng; Song, Mengjia

    2016-01-01

    Reactive oxygen species (ROS) produced by cellular metabolism play an important role as signaling messengers in immune system. ROS elevated in the tumor microenvironment are associated with tumor-induced immunosuppression. T cell-based therapy has been recently approved to be effective for cancer treatment. However, T cells often become dysfunctional after reaching the tumor site. It has been reported that ROS participate extensively in T cells activation, apoptosis, and hyporesponsiveness. The sensitivity of T cells to ROS varies among different subsets. ROS