B and T Lymphocyte Attenuator Down-regulation by HIV-1 Depends on Type I Interferon and Contributes to T-Cell Hyperactivation

PubMed Central

Zhang, Zheng; Xu, Xiangsheng; Lu, Jiyun; Zhang, Shuye; Gu, Lanlan; Fu, Junliang; Jin, Lei; Li, Haiying; Zhao, Min; Zhang, Jiyuan; Wu, Hao; Su, Lishan; Fu, Yang-Xin

2011-01-01

Background. Nonspecific T-cell hyperactivation is the main driving force for human immunodeficiency virus (HIV)–1 disease progression, but the reasons why the excess immune response is not properly shut off are poorly defined. Methods. Eighty-five HIV-1–infected individuals were enrolled to characterize B and T lymphocyte attenuator (BTLA) expression and function. Infection and blockade assays were used to dissect the factors that influenced BTLA signaling in vitro. Results. BTLA expression on overall CD4+ and CD8+ T cells was progressively decreased in HIV-1 infection, which was directly correlated with disease progression and CD4+ T-cell differentiation and activation. BTLA+CD4+ T cells from HIV-1–infected patients also displayed an altered immune status, which was indicated by reduced expression of naive markers but increased activation and exhaustion markers. Cross-linking of BTLA can substantially decrease CD4+ T-cell activation in vitro. This responsiveness of CD4+ T cells to BTLA-mediated inhibitory signaling was further found to be impaired in HIV-1–infected patients. Furthermore, HIV-1 NL4-3 down-regulated BTLA expression on CD4+ T cells dependent on plasmacytoid dendritic cell (pDC)-derived interferon (IFN)-α. Blockade of IFN-α or depletion of pDCs prevents HIV-1-induced BTLA down-regulation. Conclusions. HIV-1 infection potentially impairs BTLA-mediated signaling dependent on pDC-derived IFN-α, which may contribute to broad T-cell hyperactivation induced by chronic HIV-1 infection. PMID:21592997

Human germinal center CD4+CD57+ T cells act differently on B cells than do classical T-helper cells.

PubMed

Bouzahzah, F; Bosseloir, A; Heinen, E; Simar, L J

1995-01-01

We have isolated two subtypes of helper T cells from human tonsils: CD4+CD57+ cells, mostly located in the germinal center (GC), and CD4+CD57- cells, distributed through the interfollicular areas but also present in the GC. In a functional study, we have compared the capacities of these T-cell subtypes to stimulate B cells in cocultures. In order to block T-cell proliferation while maintaining their activation level, we pretreated isolated T cells with mitomycin C prior to culture in the presence of B cells and added polyclonal activators such as PHA and Con A, combined or not with IL-2. Contrary to CD4+ CD57- cells, CD4+CD57+ cells did not markedly enhance B-cell proliferation. Even when sIgD.B cells typical of germinal center cells were tested, the CD4+CD57+ cells had no significant effect. This is in accordance with the location of these cells: They mainly occupy the light zones of the GC where few B cells divide. Even when added to preactivated, actively proliferating cells, CD4+CD57 cells failed to modulate B-cell multiplication. On the supernatants of B-cell-T-cell cocultures, we examined by the ELISA technique the effect of T cells on Ig synthesis. Contrary to CD57+ T cells, whose effect was strong, CD57- T cells weakly stimulated Ig synthesis. More IgM than IgG was generally found. Because CD57 antigen is a typical marker of natural killer cells, we tested the cytolytic activity of tonsillar CD4+CD57+ cells on K562 target cells. Unlike NK cells, neither CD4+CD57+ nor CD4+CD57- cells exhibit any cytotoxicity. Thus, germinal center CD4+CD57+ cells are not cytolytic and do not strongly stimulate either B-cell proliferation or Ig secretion. CD4+CD57- cells, however, enhance B-cell proliferation and differentiation, thus acting like the classical helper cells of the T-dependent areas.

γδ T Cells Shape Preimmune Peripheral B Cell Populations.

PubMed

Huang, Yafei; Getahun, Andrew; Heiser, Ryan A; Detanico, Thiago O; Aviszus, Katja; Kirchenbaum, Greg A; Casper, Tamara L; Huang, Chunjian; Aydintug, M Kemal; Carding, Simon R; Ikuta, Koichi; Huang, Hua; Wysocki, Lawrence J; Cambier, John C; O'Brien, Rebecca L; Born, Willi K

2016-01-01

We previously reported that selective ablation of certain γδ T cell subsets, rather than removal of all γδ T cells, strongly affects serum Ab levels in nonimmunized mice. This type of manipulation also changed T cells, including residual γδ T cells, revealing some interdependence of γδ T cell populations. For example, in mice lacking Vγ4(+) and Vγ6(+) γδ T cells (B6.TCR-Vγ4(-/-)/6(-/-)), we observed expanded Vγ1(+) cells, which changed in composition and activation and produced more IL-4 upon stimulation in vitro, increased IL-4 production by αβ T cells as well as spontaneous germinal center formation in the spleen, and elevated serum Ig and autoantibodies. We therefore examined B cell populations in this and other γδ-deficient mouse strains. Whereas immature bone marrow B cells remained largely unchanged, peripheral B cells underwent several changes. Specifically, transitional and mature B cells in the spleen of B6.TCR-Vγ4(-/-)/6(-/-) mice and other peripheral B cell populations were diminished, most of all splenic marginal zone (MZ) B cells. However, relative frequencies and absolute numbers of Ab-producing cells, as well as serum levels of Abs, IL-4, and BAFF, were increased. Cell transfers confirmed that these changes are directly dependent on the altered γδ T cells in this strain and on their enhanced potential of producing IL-4. Further evidence suggests the possibility of direct interactions between γδ T cells and B cells in the splenic MZ. Taken together, these data demonstrate the capability of γδ T cells of modulating size and productivity of preimmune peripheral B cell populations. Copyright © 2015 by The American Association of Immunologists, Inc.

Eupatilin inhibits T-cell activation by modulation of intracellular calcium flux and NF-kappaB and NF-AT activity.

PubMed

Kim, Young-Dae; Choi, Suck-Chei; Oh, Tae-Young; Chun, Jang-Soo; Jun, Chang-Duk

2009-09-01

Eupatilin, one of the pharmacologically active ingredients of Artemisia princeps, exhibits a potent anti-ulcer activity, but its effects on T-cell immunity have not been investigated. Here, we show that eupatilin has a profound inhibitory effect on IL-2 production in Jurkat T cells as well as in human peripheral blood leukocytes. Eupatilin neither influenced clustering of CD3 and LFA-1 to the immunological synapse nor inhibited conjugate formation between T cells and B cells in the presence or absence of superantigen (SEE). Eupatilin also failed to inhibit T-cell receptor (TCR) internalization, thereby, suggesting that eupatilin does not interfere with TCR-mediated signals on the membrane proximal region. In unstimulated T cells, eupatilin significantly induced apoptotic cell death, as evidenced by an increased population of annexin V(+)/PI(+) cells and cleavage of caspase-3 and PARP. To our surprise, however, once cells were activated, eupatilin had little effect on apoptosis, and instead slightly protected cells from activation-induced cell death, suggesting that apoptosis also is not a mechanism for eupatilin-induced T-cell suppression. On the contrary, eupatilin dramatically inhibited I-kappaBalpha degradation and NF-AT dephosphorylation and, consequently, inhibited NF-kappaB and NF-AT promoter activities in PMA/A23187-stimulated T cells. Interestingly, intracellular calcium flux was significantly perturbed in cells pre-treated with eupatilin, suggesting that calcium-dependent cascades might be targets for eupatilin action. Collectively, our results provide evidence for dual regulatory functions of eupatilin: (1) a pro-apoptotic effect on resting T cells and (2) an immunosuppressive effect on activated T cells, presumably through modulation of Ca(2+) flux. (c) 2009 Wiley-Liss, Inc.

Anergic self-reactive B cells present self antigen and respond normally to CD40-dependent T-cell signals but are defective in antigen-receptor-mediated functions.

PubMed Central

Eris, J M; Basten, A; Brink, R; Doherty, K; Kehry, M R; Hodgkin, P D

1994-01-01

B-cell tolerance to soluble protein self antigens such as hen egg lysozyme (HEL) is mediated by clonal anergy. Anergic B cells fail to mount antibody responses even in the presence of carrier-primed T cells, suggesting an inability to activate or respond to T helper cells. To investigate the nature of this defect, B cells from tolerant HEL/anti-HEL double-transgenic mice were incubated with a membrane preparation from activated T-cell clones expressing the CD40 ligand. These membranes, together with interleukin 4 and 5 deliver the downstream antigen-independent CD40-dependent B-cell-activating signals required for productive T-B collaboration. Anergic B cells responded to this stimulus by proliferating and secreting antibody at levels comparable to or better than control B cells. Furthermore, anergic B cells presented HEL acquired in vivo and could present the unrelated antigen, conalbumin, targeted for processing via surface IgD. In contrast, the low immunoglobulin receptor levels on anergic B cells were associated with reduced de novo presentation of HEL and a failure to upregulate costimulatory ligands for CD28. These defects in immunoglobulin-receptor-mediated functions could be overcome in vivo, suggesting a number of mechanisms for induction of autoantibody responses. Images PMID:7514304

A Critical Role for IL-17RB Signaling in HTLV-1 Tax-Induced NF-κB Activation and T-Cell Transformation

PubMed Central

Lavorgna, Alfonso; Matsuoka, Masao; Harhaj, Edward William

2014-01-01

Human T-cell leukemia virus type 1 (HTLV-1) infection is linked to the development of adult T-cell leukemia (ATL) and the neuroinflammatory disease HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-1 Tax protein functions as a potent viral oncogene that constitutively activates the NF-κB transcription factor to transform T cells; however, the underlying mechanisms remain obscure. Here, using next-generation RNA sequencing we identified the IL-25 receptor subunit IL-17RB as an aberrantly overexpressed gene in HTLV-1 immortalized T cells. Tax induced the expression of IL-17RB in an IκB kinase (IKK) and NF-κB-dependent manner. Remarkably, Tax activation of the canonical NF-κB pathway in T cells was critically dependent on IL-17RB expression. IL-17RB and IL-25 were required for HTLV-1-induced immortalization of primary T cells, and the constitutive NF-κB activation and survival of HTLV-1 transformed T cells. IL-9 was identified as an important downstream target gene of the IL-17RB pathway that drives the proliferation of HTLV-1 transformed cells. Furthermore, IL-17RB was overexpressed in leukemic cells from a subset of ATL patients and also regulated NF-κB activation in some, but not all, Tax-negative ATL cell lines. Together, our results support a model whereby Tax instigates an IL-17RB-NF-κB feed-forward autocrine loop that is obligatory for HTLV-1 leukemogenesis. PMID:25340344

Studies on B-cell memory. III. T-dependent aspect of B memory generation in mice immunized with T-independent type-2(TI-2) antigen.

PubMed

Hosokawa, T; Tanaka, Y; Aoike, A; Kawai, K; Muramatsu, S

1984-09-01

The time course of B-cell memory development to a dinitrophenyl (DNP) T-independent type-2 (TI-2) antigen was investigated by adoptive cell transfer. Strong IgM and IgG memory developed in BALB/c mice after immunization with DNP-dextran, to be recalled by challenge with either T-dependent (TD) antigen or TI-2 antigen. However, only weak IgM memory and very feeble IgG memory were detected in athymic nude mice receiving the same immunization as euthymic mice. Once memory was established under probable T cell influence, its recall by TI-2 antigen challenge seemed independent of T cell help and did not require sharing of carriers between priming and challenge antigens. The following may be concluded. (i) Long-term IgM and IgG memory is induced by TI-2 antigen priming in the presence of functional T cells. (ii) The class switch from IgM to IgG in the memory B cell pool is driven effectively by TI-2 antigen and is probably T cell-dependent.

Switch-mediated activation and retargeting of CAR-T cells for B-cell malignancies

PubMed Central

Rodgers, David T.; Mazagova, Magdalena; Hampton, Eric N.; Cao, Yu; Ramadoss, Nitya S.; Hardy, Ian R.; Schulman, Andrew; Du, Juanjuan; Wang, Feng; Singer, Oded; Ma, Jennifer; Nunez, Vanessa; Shen, Jiayin; Woods, Ashley K.; Wright, Timothy M.; Schultz, Peter G.; Kim, Chan Hyuk; Young, Travis S.

2016-01-01

Chimeric antigen receptor T (CAR-T) cell therapy has produced impressive results in clinical trials for B-cell malignancies. However, safety concerns related to the inability to control CAR-T cells once infused into the patient remain a significant challenge. Here we report the engineering of recombinant antibody-based bifunctional switches that consist of a tumor antigen-specific Fab molecule engrafted with a peptide neo-epitope, which is bound exclusively by a peptide-specific switchable CAR-T cell (sCAR-T). The switch redirects the activity of the bio-orthogonal sCAR-T cells through the selective formation of immunological synapses, in which the sCAR-T cell, switch, and target cell interact in a structurally defined and temporally controlled manner. Optimized switches specific for CD19 controlled the activity, tissue-homing, cytokine release, and phenotype of sCAR-T cells in a dose-titratable manner in a Nalm-6 xenograft rodent model of B-cell leukemia. The sCAR–T-cell dosing regimen could be tuned to provide efficacy comparable to the corresponding conventional CART-19, but with lower cytokine levels, thereby offering a method of mitigating cytokine release syndrome in clinical translation. Furthermore, we demonstrate that this methodology is readily adaptable to targeting CD20 on cancer cells using the same sCAR-T cell, suggesting that this approach may be broadly applicable to heterogeneous and resistant tumor populations, as well as other liquid and solid tumor antigens. PMID:26759369

γδ T Cells Shape Pre-Immune Peripheral B Cell Populations

PubMed Central

Huang, Yafei; Getahun, Andrew; Heiser, Ryan A.; Detanico, Thiago O.; Aviszus, Katja; Kirchenbaum, Greg A.; Casper, Tamara L.; Huang, Chunjian; Aydintug, M. Kemal; Carding, Simon R.; Ikuta, Koichi; Huang, Hua; Wysocki, Lawrence J.; Cambier, John C.; O’Brien, Rebecca L.; Born, Willi K.

2015-01-01

We previously reported that selective ablation of certain γδ T cell subsets rather than removal of all γδ T cells, strongly affects serum antibody levels in non-immunized mice. This type of manipulation also changed T cells including residual γδ T cells, revealing some interdependence of γδ T cell populations. For example, in mice lacking Vγ4+ and Vγ6+ γδ T cells (B6.TCR-Vγ4−/−/6−/−), we observed expanded Vγ1+ cells, which changed in composition and activation and produced more IL-4 upon stimulation in vitro, increased IL-4 production by αβ T cells as well as spontaneous germinal center formation in the spleen, elevated serum Ig and autoantibodies. We therefore examined B cell populations in this and other γδ-deficient mouse strains. Whereas immature bone marrow B cells remained largely unchanged, peripheral B cells underwent several changes. Specifically, transitional and mature B cells in the spleen of B6.TCR-Vγ4−/−/6−/− mice and other peripheral B cell populations were diminished, most of all splenic marginal zone (MZ) B cells. However, relative frequencies and absolute numbers of antibody-producing cells, and serum levels of antibodies, IL-4 and BAFF, were increased. Cell transfers confirmed that these changes are directly dependent on the altered γδ T cells in this strain, and their enhanced potential of producing IL-4. Further evidence suggests the possibility of direct interactions between γδ T cells and B cells in the splenic MZ. Together, these data demonstrate the capability of γδ T cells of modulating size and productivity of pre-immune peripheral B cell populations. PMID:26582947

CXCR5-Dependent Entry of CD8 T Cells into Rhesus Macaque B-Cell Follicles Achieved through T-Cell Engineering.

PubMed

Ayala, Victor I; Deleage, Claire; Trivett, Matthew T; Jain, Sumiti; Coren, Lori V; Breed, Matthew W; Kramer, Joshua A; Thomas, James A; Estes, Jacob D; Lifson, Jeffrey D; Ott, David E

2017-06-01

Follicular helper CD4 T cells, T FH , residing in B-cell follicles within secondary lymphoid tissues, are readily infected by AIDS viruses and are a major source of persistent virus despite relative control of viral replication. This persistence is due at least in part to a relative exclusion of effective antiviral CD8 T cells from B-cell follicles. To determine whether CD8 T cells could be engineered to enter B-cell follicles, we genetically modified unselected CD8 T cells to express CXC chemokine receptor 5 (CXCR5), the chemokine receptor implicated in cellular entry into B-cell follicles. Engineered CD8 T cells expressing human CXCR5 (CD8 hCXCR5 ) exhibited ligand-specific signaling and chemotaxis in vitro Six infected rhesus macaques were infused with differentially fluorescent dye-labeled autologous CD8 hCXCR5 and untransduced CD8 T cells and necropsied 48 h later. Flow cytometry of both spleen and lymph node samples revealed higher frequencies of CD8 hCXCR5 than untransduced cells, consistent with preferential trafficking to B-cell follicle-containing tissues. Confocal fluorescence microscopy of thin-sectioned lymphoid tissues demonstrated strong preferential localization of CD8 hCXCR5 T cells within B-cell follicles with only rare cells in extrafollicular locations. CD8 hCXCR5 T cells were present throughout the follicles with some observed near infected T FH In contrast, untransduced CD8 T cells were found in the extrafollicular T-cell zone. Our ability to direct localization of unselected CD8 T cells into B-cell follicles using CXCR5 expression provides a strategy to place highly effective virus-specific CD8 T cells into these AIDS virus sanctuaries and potentially suppress residual viral replication. IMPORTANCE AIDS virus persistence in individuals under effective drug therapy or those who spontaneously control viremia remains an obstacle to definitive treatment. Infected follicular helper CD4 T cells, T FH , present inside B-cell follicles represent a

γδ T cells affect IL-4 production and B-cell tolerance

PubMed Central

Huang, Yafei; Heiser, Ryan A.; Detanico, Thiago O.; Getahun, Andrew; Kirchenbaum, Greg A.; Casper, Tamara L.; Aydintug, M. Kemal; Carding, Simon R.; Ikuta, Koichi; Huang, Hua; Cambier, John C.; Wysocki, Lawrence J.; O’Brien, Rebecca L.; Born, Willi K.

2015-01-01

γδ T cells can influence specific antibody responses. Here, we report that mice deficient in individual γδ T-cell subsets have altered levels of serum antibodies, including all major subclasses, sometimes regardless of the presence of αβ T cells. One strain with a partial γδ deficiency that increases IgE antibodies also displayed increases in IL-4–producing T cells (both residual γδ T cells and αβ T cells) and in systemic IL-4 levels. Its B cells expressed IL-4–regulated inhibitory receptors (CD5, CD22, and CD32) at diminished levels, whereas IL-4–inducible IL-4 receptor α and MHCII were increased. They also showed signs of activation and spontaneously formed germinal centers. These mice displayed IgE-dependent features found in hyper-IgE syndrome and developed antichromatin, antinuclear, and anticytoplasmic autoantibodies. In contrast, mice deficient in all γδ T cells had nearly unchanged Ig levels and did not develop autoantibodies. Removing IL-4 abrogated the increases in IgE, antichromatin antibodies, and autoantibodies in the partially γδ-deficient mice. Our data suggest that γδ T cells, controlled by their own cross-talk, affect IL-4 production, B-cell activation, and B-cell tolerance. PMID:25535377

γδ T cells affect IL-4 production and B-cell tolerance.

PubMed

Huang, Yafei; Heiser, Ryan A; Detanico, Thiago O; Getahun, Andrew; Kirchenbaum, Greg A; Casper, Tamara L; Aydintug, M Kemal; Carding, Simon R; Ikuta, Koichi; Huang, Hua; Cambier, John C; Wysocki, Lawrence J; O'Brien, Rebecca L; Born, Willi K

2015-01-06

γδ T cells can influence specific antibody responses. Here, we report that mice deficient in individual γδ T-cell subsets have altered levels of serum antibodies, including all major subclasses, sometimes regardless of the presence of αβ T cells. One strain with a partial γδ deficiency that increases IgE antibodies also displayed increases in IL-4-producing T cells (both residual γδ T cells and αβ T cells) and in systemic IL-4 levels. Its B cells expressed IL-4-regulated inhibitory receptors (CD5, CD22, and CD32) at diminished levels, whereas IL-4-inducible IL-4 receptor α and MHCII were increased. They also showed signs of activation and spontaneously formed germinal centers. These mice displayed IgE-dependent features found in hyper-IgE syndrome and developed antichromatin, antinuclear, and anticytoplasmic autoantibodies. In contrast, mice deficient in all γδ T cells had nearly unchanged Ig levels and did not develop autoantibodies. Removing IL-4 abrogated the increases in IgE, antichromatin antibodies, and autoantibodies in the partially γδ-deficient mice. Our data suggest that γδ T cells, controlled by their own cross-talk, affect IL-4 production, B-cell activation, and B-cell tolerance.

B cell depletion reduces T cell activation in pancreatic islets in a murine autoimmune diabetes model.

PubMed

Da Rosa, Larissa C; Boldison, Joanne; De Leenheer, Evy; Davies, Joanne; Wen, Li; Wong, F Susan

2018-06-01

Type 1 diabetes is a T cell-mediated autoimmune disease characterised by the destruction of beta cells in the islets of Langerhans, resulting in deficient insulin production. B cell depletion therapy has proved successful in preventing diabetes and restoring euglycaemia in animal models of diabetes, as well as in preserving beta cell function in clinical trials in the short term. We aimed to report a full characterisation of B cell kinetics post B cell depletion, with a focus on pancreatic islets. Transgenic NOD mice with a human CD20 transgene expressed on B cells were injected with an anti-CD20 depleting antibody. B cells were analysed using multivariable flow cytometry. There was a 10 week delay in the onset of diabetes when comparing control and experimental groups, although the final difference in the diabetes incidence, following prolonged observation, was not statistically significant (p = 0.07). The co-stimulatory molecules CD80 and CD86 were reduced on stimulation of B cells during B cell depletion and repopulation. IL-10-producing regulatory B cells were not induced in repopulated B cells in the periphery, post anti-CD20 depletion. However, the early depletion of B cells had a marked effect on T cells in the local islet infiltrate. We demonstrated a lack of T cell activation, specifically with reduced CD44 expression and effector function, including IFN-γ production from both CD4 + and CD8 + T cells. These CD8 + T cells remained altered in the pancreatic islets long after B cell depletion and repopulation. Our findings suggest that B cell depletion can have an impact on T cell regulation, inducing a durable effect that is present long after repopulation. We suggest that this local effect of reducing autoimmune T cell activity contributes to delay in the onset of autoimmune diabetes.

TLR4- and TRIF-dependent stimulation of B lymphocytes by peptide liposomes enables T cell-independent isotype switch in mice.

PubMed

Pihlgren, Maria; Silva, Alberto B; Madani, Rime; Giriens, Valérie; Waeckerle-Men, Ying; Fettelschoss, Antonia; Hickman, David T; López-Deber, María Pilar; Ndao, Dorin Mlaki; Vukicevic, Marija; Buccarello, Anna Lucia; Gafner, Valérie; Chuard, Nathalie; Reis, Pedro; Piorkowska, Kasia; Pfeifer, Andrea; Kündig, Thomas M; Muhs, Andreas; Johansen, Pål

2013-01-03

Immunoglobulin class switching from IgM to IgG in response to peptides is generally T cell-dependent and vaccination in T cell-deficient individuals is inefficient. We show that a vaccine consisting of a dense array of peptides on liposomes induced peptide-specific IgG responses totally independent of T-cell help. Independency was confirmed in mice lacking T cells and in mice deficient for MHC class II, CD40L, and CD28. The IgG titers were high, long-lived, and comparable with titers obtained in wild-type animals, and the antibody response was associated with germinal center formation, expression of activation-induced cytidine deaminase, and affinity maturation. The T cell-independent (TI) IgG response was strictly dependent on ligation of TLR4 receptors on B cells, and concomitant TLR4 and cognate B-cell receptor stimulation was required on a single-cell level. Surprisingly, the IgG class switch was mediated by TIR-domain-containing adapter inducing interferon-β (TRIF), but not by MyD88. This study demonstrates that peptides can induce TI isotype switching when antigen and TLR ligand are assembled and appropriately presented directly to B lymphocytes. A TI vaccine could enable efficient prophylactic and therapeutic vaccination of patients with T-cell deficiencies and find application in diseases where induction of T-cell responses contraindicates vaccination, for example, in Alzheimer disease.

Regulatory T cells control HIV replication in activated T cells through a cAMP-dependent mechanism

PubMed Central

Moreno-Fernandez, Maria E.; Rueda, Cesar Mauricio; Rusie, Laura K.

2011-01-01

We hypothesized that regulatory T cells (Tregs) could play a beneficial role during HIV infection by controlling HIV replication in conventional T cells (Tcons). Purified Tregs and Tcons from healthy donors were activated separately. Tcons were infected with the X4 or R5 HIV strains and cultured with or without autologous Tregs. Coculture of Tcons and Tregs resulted in a dose-dependent inhibition of Tcon infection, which was significant when a 1:1 Treg:Tcon ratio was used. Treg suppression of HIV infection was largely mediated by contact-dependent mechanisms. Blockage of cytotoxic T-lymphocyte–associated antigen-4 did not significantly reduce Treg function. In contrast, Tregs acted through cAMP-dependent mechanisms, because the decrease of cAMP levels in Tregs, the blockade of gap junction formation between Tregs and Tcons, the blockage of CD39 activity, and the blockage of protein kinase A in Tcons all abolished Treg-mediated suppression of HIV replication. Our data suggest a complex role for Tregs during HIV infection. Although Tregs inhibit specific immune responses, their inhibition of HIV replication in Tcons may play a beneficial role, particularly during early HIV infection, when the effector immune cells are not yet activated. Such a protective role of Tregs could have a profound impact on infection outcome. PMID:21436067

Myeloid-derived suppressor cells regulate T cell and B cell responses during autoimmune disease.

PubMed

Crook, Kristen R; Jin, Mengyao; Weeks, Michael F; Rampersad, Rishi R; Baldi, Robert M; Glekas, Amy S; Shen, Yajuan; Esserman, Denise A; Little, Paul; Schwartz, Todd A; Liu, Peng

2015-03-01

MDSCs are a heterogeneous group of myeloid cells that suppress T cell activity in cancer and autoimmune disease. The effect of MDSCs on B cell function is not clear. Using the CIA model of autoimmune disease, we found an increase in M-MDSCs in the periphery of WT mice with CIA compared with naïve mice. These MDSCs were absent from the periphery of CCR2(-/-) mice that developed exacerbated disease. M-MDSCs, isolated from immunized mice, inhibited autologous CD4(+) T cell proliferation. The M-MDSC-mediated suppression of T cell proliferation was NO and IFN-γ dependent but IL-17 independent. Furthermore, we demonstrated for the first time that M-MDSCs from CIA mice also inhibited autologous B cell proliferation and antibody production. The suppression of B cells by M-MDSCs was dependent on the production of NO and PGE2 and required cell-cell contact. Administration of M-MDSCs rescued CCR2(-/-) mice from the exacerbated CIA phenotype and ameliorated disease in WT mice. Furthermore, adoptive transfer of M-MDSCs reduced autoantibody production by CCR2(-/-) and WT mice. In summary, M-MDSCs inhibit T cell and B cell function in CIA and may serve as a therapeutic approach in the treatment of autoimmune arthritis. © Society for Leukocyte Biology.

Defective B cell response to T-dependent immunization in lupus-prone mice

PubMed Central

Niu, Haitao; Sobel, Eric S.; Morel, Laurence

2009-01-01

Lupus anti-nuclear Abs show the characteristics of Ag-driven T cell-dependent (TD) humoral responses. If autoAgs elicit the same response as exogenous Ags, lupus should enhance humoral responses to immunization. Blunted responses to various immunizations have, however, been reported in a significant portion of lupus patients. In this study, we show that lupus-prone B6.Sle1.Sle2.Sle3 (B6.TC) mice produce significantly less Ab in response to TD immunization than congenic controls, while producing significantly more total Ig. This blunted Ab response to TD Ag could be reconstituted with B6.TC B and CD4+ T cells. Multiple defects were found in the B6.TC response to NP-KLH as compared to total Ig, including a smaller percentage of B cells participating to the NP-response, a reduced entry into germinal centers, and highly defective production of NP-specific long-lived plasma cells in the bone marrow. B6.TC plasma cells expressed reduced levels of FcγRIIb, which suggests that reduced apoptosis in resident plasma cells prevents the establishment of newly-formed NP-specific plasma cells in bone marrow niches. Overall, these results show that lupus-prone mice responded differently to auto- and exogenous antigens and suggest that low FcγRIIb, hypergammaglobulinemia and high autoantibody production would be predictive of a poor response to immunization in lupus patients. PMID:18924209

Naive T-cell receptor transgenic T cells help memory B cells produce antibody

PubMed Central

Duffy, Darragh; Yang, Chun-Ping; Heath, Andrew; Garside, Paul; Bell, Eric B

2006-01-01

Injection of the same antigen following primary immunization induces a classic secondary response characterized by a large quantity of high-affinity antibody of an immunoglobulin G class produced more rapidly than in the initial response – the products of memory B cells are qualitatively distinct from that of the original naive B lymphocytes. Very little is known of the help provided by the CD4 T cells that stimulate memory B cells. Using antigen-specific T-cell receptor transgenic CD4 T cells (DO11.10) as a source of help, we found that naive transgenic T cells stimulated memory B cells almost as well (in terms of quantity and speed) as transgenic T cells that had been recently primed. There was a direct correlation between serum antibody levels and the number of naive transgenic T cells transferred. Using T cells from transgenic interleukin-2-deficient mice we showed that interleukin-2 was not required for a secondary response, although it was necessary for a primary response. The results suggested that the signals delivered by CD4 T cells and required by memory B cells for their activation were common to both antigen-primed and naive CD4 T cells. PMID:17067314

Activation Loop Dynamics Determine the Different Catalytic Efficiencies of B Cell- and T Cell-Specific Tec Kinases

PubMed Central

Joseph, Raji E.; Kleino, Iivari; Wales, Thomas E.; Xie, Qian; Fulton, D. Bruce; Engen, John R.; Berg, Leslie J.; Andreotti, Amy H.

2014-01-01

Itk and Btk are nonreceptor tyrosine kinases of the Tec family that signal downstream of the T cell receptor (TCR) and B cell receptor (BCR), respectively. Despite their high sequence similarity and related signaling roles, Btk is a substantially more active kinase than Itk. We showed that substitution of six of the 619 amino acid residues of Itk with those of Btk was sufficient to completely switch the activities of Itk and Btk. The substitutions responsible for the swap in activity are all localized to the activation segment of the kinase domain. Nuclear magnetic resonance and hydrogen-deuterium exchange mass spectrometry analyses revealed that Itk and Btk had distinct protein dynamics in this region, which could explain the observed differences in catalytic efficiency between these kinases. Introducing Itk with enhanced activity into T cells led to enhanced and prolonged TCR signaling compared to that in cells with wild-type Itk. These findings imply that evolutionary pressures have led to Tec kinases having distinct enzymatic properties depending on the cellular context. We suggest that the weaker catalytic activities observed for T cell–specific kinases is one mechanism to regulate cellular activation and prevent aberrant immune responses. PMID:23982207

Vav1-phospholipase C-γ1 (Vav1-PLC-γ1) pathway initiated by T cell antigen receptor (TCRγδ) activation is required to overcome inhibition by ubiquitin ligase Cbl-b during γδT cell cytotoxicity.

PubMed

Yin, Shanshan; Zhang, Jianmin; Mao, Yujia; Hu, Yu; Cui, Lianxian; Kang, Ning; He, Wei

2013-09-13

T cell antigen receptor γδ (TCRγδ) and natural killer group 2, member D (NKG2D) are two crucial receptors for γδT cell cytotoxicity. Compelling evidences suggest that γδT cell cytotoxicity is TCRγδ-dependent and can be co-stimulated by NKG2D. However, the molecular mechanism of underlying TCRγδ-dependent activation of γδT cells remains unclear. In this study we demonstrated that TCRγδ but not NKG2D engagement induced lytic granule polarization and promoted γδT cell cytotoxicity. TCRγδ activation alone was sufficient to trigger Vav1-dependent phospholipase C-γ1 signaling, resulting in lytic granule polarization and effective killing, whereas NKG2D engagement alone failed to trigger cytotoxicity-related signaling to overcome the inhibitory effect of Cbl-b; therefore, NKG2D engagement alone could not induce effective killing. However, NKG2D ligation augmented the activation of γδT cell cytotoxicity through the Vav1-phospholipase C-γ1 pathway. Vav1 overexpression or Cbl-b knockdown not only enhanced TCRγδ activation-initiated killing but also enabled NKG2D activation alone to induce γδT cell cytotoxicity. Taken together, our results suggest that the activation of γδT cell cytotoxicity requires a strong activation signal to overcome the inhibitory effect of Cbl-b. Our finding provides new insights into the molecular mechanisms underlying the initiation of γδT cell cytotoxicity and likely implications for optimizing γδT cell-based cancer immunotherapy.

Modulation of T Cell Activation by Malignant Melanoma Initiating Cells

PubMed Central

Schatton, Tobias; Schütte, Ute; Frank, Natasha Y.; Zhan, Qian; Hoerning, André; Robles, Susanne C.; Zhou, Jun; Hodi, F. Stephen; Spagnoli, Giulio C.; Murphy, George F.; Frank, Markus H.

2010-01-01

Highly immunogenic cancers such as malignant melanoma are capable of inexorable tumor growth despite the presence of antitumor immunity. This raises the possibility that only a restricted minority of tumorigenic malignant cells might possess the phenotypic and functional characteristics to modulate tumor-directed immune activation. Here we provide evidence supporting this hypothesis, by demonstrating that tumorigenic ABCB5+ malignant melanoma-initiating cells (MMICs) possess the capacity to preferentially inhibit interleukin (IL)-2-dependent T cell activation and to support, in a B7.2-dependent manner, regulatory T (Treg) cell induction. Compared to melanoma bulk populations, ABCB5+ MMICs expressed lower levels of the major histocompatibility complex (MHC) class I, showed aberrant positivity for MHC class II, and exhibited lower expression levels of the melanoma-associated antigens (MAAs) MART-1, ML-IAP, NY-ESO-1, and MAGE-A. In addition, tumorigenic ABCB5+ subpopulations preferentially expressed the costimulatory molecules B7.2 and PD-1 in both established melanoma xenografts and clinical tumor specimens in vivo. In immune activation assays, ABCB5+ melanoma cells inhibited mitogen-dependent human peripheral blood mononuclear cell (PBMC) proliferation and IL-2 production more efficiently than ABCB5− populations. Moreover, coculture with ABCB5+ MMICs increased, in a B7.2 signalling-dependent manner, CD4+CD25+FoxP3+ Treg cell abundance and IL-10 production by mitogen-activated PBMCs. Consistent with these findings, ABCB5+ melanoma subsets also preferentially inhibited IL-2 production and induced IL-10 secretion by cocultured patient-derived, syngeneic PBMCs. Our findings identify novel T cell-modulatory functions of ABCB5+ melanoma subpopulations and suggest specific roles for MMICs in the evasion of antitumor immunity and in cancer immunotherapeutic resistance. PMID:20068175

CD8+ memory T-cell inflation renders compromised CD4+ T-cell-dependent CD8+ T-cell immunity via naïve T-cell anergy.

PubMed

Xu, Aizhang; Freywald, Andrew; Xie, Yufeng; Li, Zejun; Xiang, Jim

2017-01-01

Whether inflation of CD8 + memory T (mT) cells, which is often derived from repeated prime-boost vaccinations or chronic viral infections in the elderly, would affect late CD8 + T-cell immunity is a long-standing paradox. We have previously established an animal model with mT-cell inflation by transferring ConA-stimulated monoclonal CD8 + T cells derived from Ova-specific T-cell-receptor transgenic OTI mice into irradiation-induced lymphopenic B6 mice. In this study, we also established another two animal models with mT-cell inflation by transferring, 1) ConA-stimulated monoclonal CD8 + T cells derived from lymphocytic choriomeningitis virus glycoprotein-specific T-cell-receptor transgenic P14 mice, and 2) ConA-stimulated polyclonal CD8 + T cells derived from B6.1 mice into B6 mice with irradiation-induced lymphopenia. We vaccinated these mice with recombinant Ova-expressing Listeria monocytogenes and Ova-pulsed dendritic cells, which stimulated CD4 + T cell-independent and CD4 + T-cell-dependent CD8 + T-cell responses, respectively, and assessed Ova-specific CD8 + T-cell responses by flow cytometry. We found that Ova-specific CD8 + T-cell responses derived from the latter but not the former vaccination were significantly reduced in mice with CD8 + mT-cell inflation compared to wild-type B6 mice. We determined that naïve CD8 + T cells purified from splenocytes of mice with mT-cell inflation had defects in cell proliferation upon stimulation in vitro and in vivo and upregulated T-cell anergy-associated Itch and GRAIL molecules. Taken together, our data reveal that CD8 + mT-cell inflation renders compromised CD4 + T-cell-dependent CD8 + T-cell immunity via naïve T-cell anergy, and thus show promise for the design of efficient vaccines for elderly patients with CD8 + mT-cell inflation.

Ultraviolet B inhibition of DNMT1 activity via AhR activation dependent SIRT1 suppression in CD4+ T cells from systemic lupus erythematosus patients.

PubMed

Wu, Zhouwei; Mei, Xingyu; Ying, Zuolin; Sun, Yue; Song, Jun; Shi, Weimin

2017-06-01

Previous studies have reported that ultraviolet B (UVB) inhibits DNA methyltransferase1 (DNMT1) activity in CD4+ T cells from systemic lupus erythematosus (SLE) patients. Silent mating type information regulation 2 homolog 1 (SIRT1) is a type of Class III histone deacetylases (HDACs), and has been reported to play roles in the pathogenesis of different autoimmune diseases and can modulate DNMT1 activity. Moreover, aryl hydrocarbon receptor (AhR) has been reported to link UVB with SLE. However, the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells remain largely unknown. To elucidate the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells. Twenty-two newly diagnosed active SLE patients and 30 healthy controls were enrolled in the study. CD4+ T cells were isolated, cultured and treated. DNMT1 activity assay, quantitative real-time PCR (qRT-PCR), Western blotting, RNA interference using small interfering RNA and Chromatin Immunoprecipitation (ChIP) assay were employed. DNMT1 activity was inhibited in si-SIRT1-transfected CD4+ T cells, and increased by the established SIRT1 activator, SRT1720. Moreover, the mRNA and protein expression of SIRT1 were suppressed by UVB exposure in lupus CD4+ T cells. UVB-inhibited DNMT1 activity was reversed by SRT1720 in si-control-transfected lupus CD4+ T cells, but not in si-SIRT1-transfected lupus CD4 + T cells. Furthermore, AhR activation by VAF347 reduced the mRNA and protein expression of SIRT1. ChIP using an antibody against AhR in normal CD4+ T cells revealed a 16-fold stronger signal at the site about 1.6kb upstream from the translation start site of the SIRT1 promoter. Finally, UVB could activate AhR and inhibit the mRNA and protein expression of SIRT1. AhR knockdown abrogated the inhibition of UVB-mediated SIRT1 mRNA and protein expression and DNMT1 activity in lupus CD4+ T cells. UVB suppressed SIRT1 expression via activating AhR, and subsequently inhibited DNMT1

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells

PubMed Central

2017-01-01

ABSTRACT Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein–Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8+ T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a−/− CD8+ T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a−/− CD8+ T cells responded equivalently to wild-type CD8+ T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8+ T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8+ T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8+ T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas. PMID:28344876

2B4-SAP signaling is required for the priming of naive CD8+ T cells by antigen-expressing B cells and B lymphoma cells.

PubMed

Huang, Yu-Hsuan; Tsai, Kevin; Tan, Sara Y; Kang, Sohyeong; Ford, Mandy L; Harder, Kenneth W; Priatel, John J

2017-01-01

Mutations in SH2D1A gene that encodes SAP (SLAM-associated protein) result in X-linked lymphoproliferative disease (XLP), a rare primary immunodeficiency disease defined by exquisite sensitivity to the B-lymphotropic Epstein-Barr virus (EBV) and B cell lymphomas. However, the precise mechanism of how the loss of SAP function contributes to extreme vulnerability to EBV and the development of B cell lymphomas remains unclear. Here, we investigate the hypothesis that SAP is critical for CD8 + T cell immune surveillance of antigen (Ag)-expressing B cells or B lymphoma cells under conditions of defined T cell receptor (TCR) signaling. Sh2d1a - / - CD8 + T cells exhibited greatly diminished proliferation relative to wild type when Ag-presenting-B cells or -B lymphoma cells served as the primary Ag-presenting cell (APC). By contrast, Sh2d1a - / - CD8 + T cells responded equivalently to wild-type CD8 + T cells when B cell-depleted splenocytes, melanoma cells or breast carcinoma cells performed Ag presentation. Through application of signaling lymphocyte activation molecule (SLAM) family receptor blocking antibodies or SLAM family receptor-deficient CD8 + T cells and APCs, we found that CD48 engagement on the B cell surface by 2B4 is crucial for initiating SAP-dependent signaling required for the Ag-driven CD8 + T cell proliferation and differentiation. Altogether, a pivotal role for SAP in promoting the expansion and differentiation of B cell-primed viral-specific naive CD8 + T cells may explain the selective immune deficiency of XLP patients to EBV and B cell lymphomas.

Lymphotoxin activation by human T-cell leukemia virus type I-infected cell lines: role for NF-kappa B.

PubMed

Paul, N L; Lenardo, M J; Novak, K D; Sarr, T; Tang, W L; Ruddle, N H

1990-11-01

Human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of biologically active lymphotoxin (LT; tumor necrosis factor-beta) protein and LT mRNA. To understand the regulation of LT transcription by HTLV-I, we analyzed the ability of a series of deletions of the LT promoter to drive the chloramphenicol acetyltransferase (CAT) reporter gene in HTLV-I-positive MT-2 cells. The smallest LT promoter fragment (-140 to +77) that was able to drive CAT activity contained a site that was similar to the immunoglobulin kappa-chain NF-kappa B-binding site. Since the HTLV-I tax gene activates the nuclear form of NF-kappa B, this finding suggested a possible means of HTLV-I activation of LT production. We found that the LT kappa B-like site specifically formed a complex with NF-kappa B-containing nuclear extract from MT-2, C81-66-45, and other activated T cells. Mutation of the LT kappa B site in the context of the LT promoter (-293 to +77) (mutant M1) reduced the ability of the promoter to drive the CAT gene in HTLV-I-infected and noninfected human T-cell lines. These data suggest a general role for NF-kappa B activation in the induction of LT gene transcription. Activation of LT in HTLV-I-infected cells may explain the pathology associated with HTLV-I infection, including the hypercalcemia that is prevalent in adult T-cell leukemia.

Naive B cells generate regulatory T cells in the presence of a mature immunologic synapse.

PubMed

Reichardt, Peter; Dornbach, Bastian; Rong, Song; Beissert, Stefan; Gueler, Faikah; Loser, Karin; Gunzer, Matthias

2007-09-01

Naive B cells are ineffective antigen-presenting cells and are considered unable to activate naive T cells. However, antigen-specific contact of these cells leads to stable cell pairs that remain associated over hours in vivo. The physiologic role of such pairs has not been evaluated. We show here that antigen-specific conjugates between naive B cells and naive T cells display a mature immunologic synapse in the contact zone that is absent in T-cell-dendritic-cell (DC) pairs. B cells induce substantial proliferation but, contrary to DCs, no loss of L-selectin in T cells. Surprisingly, while DC-triggered T cells develop into normal effector cells, B-cell stimulation over 72 hours induces regulatory T cells inhibiting priming of fresh T cells in a contact-dependent manner in vitro. In vivo, the regulatory T cells home to lymph nodes where they potently suppress immune responses such as in cutaneous hypersensitivity and ectopic allogeneic heart transplant rejection. Our finding might help to explain old observations on tolerance induction by B cells, identify the mature immunologic synapse as a central functional module of this process, and suggest the use of naive B-cell-primed regulatory T cells, "bTregs," as a useful approach for therapeutic intervention in adverse adaptive immune responses.

Relative Contributions of B Cells and Dendritic Cells from Lupus-Prone Mice to CD4+ T Cell Polarization.

PubMed

Choi, Seung-Chul; Xu, Zhiwei; Li, Wei; Yang, Hong; Roopenian, Derry C; Morse, Herbert C; Morel, Laurence

2018-05-01

Mouse models of lupus have shown that multiple immune cell types contribute to autoimmune disease. This study sought to investigate the involvement of B cells and dendritic cells in supporting the expansion of inflammatory and regulatory CD4 + T cells that are critical for lupus pathogenesis. We used lupus-prone B6.NZM2410.Sle1.Sle2.Sle3 (TC) and congenic C57BL/6J (B6) control mice to investigate how the genetic predisposition of these two cell types controls the activity of normal B6 T cells. Using an allogeneic in vitro assay, we showed that TC B1-a and conventional B cells expanded Th17 cells significantly more than their B6 counterparts. This expansion was dependent on CD86 and IL-6 expression and mapped to the Sle1 lupus-susceptibility locus. In vivo, TC B cells promoted greater differentiation of CD4 + T cells into Th1 and follicular helper T cells than did B6 B cells, but they limited the expansion of Foxp3 regulatory CD4 + T cells to a greater extent than did B6 B cells. Finally, when normal B6 CD4 + T cells were introduced into Rag1 -/- mice, TC myeloid/stromal cells caused their heightened activation, decreased Foxp3 regulatory CD4 + T cell differentiation, and increased renal infiltration of Th1 and Th17 cells in comparison with B6 myeloid/stromal cells. The results show that B cells from lupus mice amplify inflammatory CD4 + T cells in a nonredundant manner with myeloid/stromal cells. Copyright © 2018 by The American Association of Immunologists, Inc.

Polyclonal activation of human lymphocytes in vitro-II. Reappraisal of T and B cell-specific mitogens.

PubMed

Dosch, H M; Schuurman, R K; Gelfand, E W

1980-08-01

The capacity of the T cell mitogens phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and Staphylococcus protein A (SpA) to induce B cell proliferation and differentiation was compared with the B cell mitogen, formalinized Staphylococcus aureus (STA). Lymphocyte subpopulations from normal donors and patients with various immunodeficiency diseases were studied. In the presence of the T cell mitogens, irradiated T cells were capable of providing a helper cell activity that enabled co-cultured B lymphocytes to proliferate in response to these mitogens and to differentiate into IgM-secreting (direct) hemolytic plaque-forming cells (PFC). In the PFC response, radioresistant T-helper and radiosensitive T-suppressor cell activities could be demonstrated. T-suppressor cell activity outweighed helper activity only in nonirradiated co-cultures stimulated with Con A. Patients with severe combined immunodeficiency lacked mitogen-induced helper T cells, whereas patients with various forms of humoral immune deficiency were normal in this respect. These findings and the tissue distribution of the helper activity is aquired early in post-thymic T cell differentiation. The data suggest that experiments with cell lineage-specific lymphocyte mitogens should be considered in the context of more complex cell-cell interactions.

The E3 ubiquitin ligase mind bomb-2 (MIB2) protein controls B-cell CLL/lymphoma 10 (BCL10)-dependent NF-κB activation.

PubMed

Stempin, Cinthia C; Chi, Liying; Giraldo-Vela, Juan P; High, Anthony A; Häcker, Hans; Redecke, Vanessa

2011-10-28

B-cell CLL/lymphoma 10 (BCL10) is crucial for the activation of NF-κB in numerous immune receptor signaling pathways, including the T-cell receptor (TCR) and B-cell receptor signaling pathways. However, the molecular mechanisms that lead to signal transduction from BCL10 to downstream NF-κB effector kinases, such as TAK1 and components of the IKK complex, are not entirely understood. Here we used a proteomic approach and identified the E3 ligase MIB2 as a novel component of the activated BCL10 complex. In vitro translation and pulldown assays suggest direct interaction between BCL10 and MIB2. Overexpression experiments show that MIB2 controls BCL10-mediated activation of NF-κB by promoting autoubiquitination and ubiquitination of IKKγ/NEMO, as well as recruitment and activation of TAK1. Knockdown of MIB2 inhibited BCL10-dependent NF-κB activation. Together, our results identify MIB2 as a novel component of the activated BCL10 signaling complex and a missing link in the BCL10-dependent NF-κB signaling pathway.

Lymphotoxin activation by human T-cell leukemia virus type I-infected cell lines: role for NF-kappa B.

PubMed Central

Paul, N L; Lenardo, M J; Novak, K D; Sarr, T; Tang, W L; Ruddle, N H

1990-01-01

Human T-cell leukemia virus type I (HTLV-I)-infected T-cell lines constitutively produce high levels of biologically active lymphotoxin (LT; tumor necrosis factor-beta) protein and LT mRNA. To understand the regulation of LT transcription by HTLV-I, we analyzed the ability of a series of deletions of the LT promoter to drive the chloramphenicol acetyltransferase (CAT) reporter gene in HTLV-I-positive MT-2 cells. The smallest LT promoter fragment (-140 to +77) that was able to drive CAT activity contained a site that was similar to the immunoglobulin kappa-chain NF-kappa B-binding site. Since the HTLV-I tax gene activates the nuclear form of NF-kappa B, this finding suggested a possible means of HTLV-I activation of LT production. We found that the LT kappa B-like site specifically formed a complex with NF-kappa B-containing nuclear extract from MT-2, C81-66-45, and other activated T cells. Mutation of the LT kappa B site in the context of the LT promoter (-293 to +77) (mutant M1) reduced the ability of the promoter to drive the CAT gene in HTLV-I-infected and noninfected human T-cell lines. These data suggest a general role for NF-kappa B activation in the induction of LT gene transcription. Activation of LT in HTLV-I-infected cells may explain the pathology associated with HTLV-I infection, including the hypercalcemia that is prevalent in adult T-cell leukemia. Images PMID:1976820

Failure in activation of the canonical NF-κB pathway by human T-cell leukemia virus type 1 Tax in non-hematopoietic cell lines

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

Mizukoshi, Terumi; Komori, Hideyuki; Mizuguchi, Mariko

2013-09-01

Human T-cell leukemia virus type 1 (HTLV-1) Tax (Tax1) plays crucial roles in leukemogenesis in part through activation of NF-κB. In this study, we demonstrated that Tax1 activated an NF-κB binding (gpκB) site of the gp34/OX40 ligand gene in a cell type-dependent manner. Our examination showed that the gpκΒ site and authentic NF-κB (IgκB) site were activated by Tax1 in hematopoietic cell lines. Non-hematopoietic cell lines including hepatoma and fibroblast cell lines were not permissive to Tax1-mediated activation of the gpκB site, while the IgκB site was activated in those cells in association with binding of RelB. However RelA bindingmore » was not observed in the gpκB and IgκB sites. Our results suggest that HTLV-1 Tax1 fails to activate the canonical pathway of NF-κB in non-hematopoietic cell lines. Cell type-dependent activation of NF-κB by Tax1 could be associated with pathogenesis by HTLV-1 infection. - Highlights: • HTLV-1 Tax1 does not activate RelA of NF-κB in non-hematopoietic cell lines. • Tax1 activates the NF-κB non-canonical pathway in non-hematopoietic cell lines. • Tax1 does not induce RelA nuclear translocation in those cell lines, unlike TNFα. • The OX40L promoter κB site is activated by ectopic, but not endogenous, RelA.« less

CD83 Antibody Inhibits Human B Cell Responses to Antigen as well as Dendritic Cell-Mediated CD4 T Cell Responses.

PubMed

Wong, Kuan Y; Baron, Rebecca; Seldon, Therese A; Jones, Martina L; Rice, Alison M; Munster, David J

2018-05-15

Anti-CD83 Ab capable of Ab-dependent cellular cytotoxicity can deplete activated CD83 + human dendritic cells, thereby inhibiting CD4 T cell-mediated acute graft-versus-host disease. As CD83 is also expressed on the surface of activated B lymphocytes, we hypothesized that anti-CD83 would also inhibit B cell responses to stimulation. We found that anti-CD83 inhibited total IgM and IgG production in vitro by allostimulated human PBMC. Also, Ag-specific Ab responses to immunization of SCID mice xenografted with human PBMC were inhibited by anti-CD83 treatment. This inhibition occurred without depletion of all human B cells because anti-CD83 lysed activated CD83 + B cells by Ab-dependent cellular cytotoxicity and spared resting (CD83 - ) B cells. In cultured human PBMC, anti-CD83 inhibited tetanus toxoid-stimulated B cell proliferation and concomitant dendritic cell-mediated CD4 T cell proliferation and expression of IFN-γ and IL-17A, with minimal losses of B cells (<20%). In contrast, the anti-CD20 mAb rituximab depleted >80% of B cells but had no effect on CD4 T cell proliferation and cytokine expression. By virtue of the ability of anti-CD83 to selectively deplete activated, but not resting, B cells and dendritic cells, with the latter reducing CD4 T cell responses, anti-CD83 may be clinically useful in autoimmunity and transplantation. Advantages might include inhibited expansion of autoantigen- or alloantigen-specific B cells and CD4 T cells, thus preventing further production of pathogenic Abs and inflammatory cytokines while preserving protective memory and regulatory cells. Copyright © 2018 by The American Association of Immunologists, Inc.

Unexpected T cell regulatory activity of anti-histone H1 autoantibody: Its mode of action in regulatory T cell-dependent and -independent manners

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

Takaoka, Yuki; Kawamoto, Seiji, E-mail: skawa@hiroshima-u.ac.jp; Katayama, Akiko

2013-02-08

Highlights: ► Anti-histone H1 autoantibody (anti-H1) acts on T cells to inhibit their activation. ► Anti-H1 suppresses T cell activation in Treg cell-dependent and -independent manners. ► Suboptimal dose of anti-H1 enhances suppressor function of Treg cells. ► High dose of anti-H1 directly inhibits T cell receptor signaling. -- Abstract: Induction of anti-nuclear antibodies against DNA or histones is a hallmark of autoimmune disorders, but their actual contribution to disease predisposition remains to be clarified. We have previously reported that autoantibodies against histone H1 work as a critical graft survival factor in a rat model of tolerogeneic liver transplantation. Heremore » we show that an immunosuppressive anti-histone H1 monoclonal antibody (anti-H1 mAb) acts directly on T cells to inhibit their activation in response to T cell receptor (TCR) ligation. Intriguingly, the T cell activation inhibitory activity of anti-H1 mAb under suboptimal dosages required regulatory T (Treg) cells, while high dose stimulation with anti-H1 mAb triggered a Treg cell-independent, direct negative regulation of T cell activation upon TCR cross-linking. In the Treg cell-dependent mode of immunosuppressive action, anti-H1 mAb did not induce the expansion of CD4{sup +}Foxp3{sup +} Treg cells, but rather potentiated their regulatory capacity. These results reveal a previously unappreciated T cell regulatory role of anti-H1 autoantibody, whose overproduction is generally thought to be pathogenic in the autoimmune settings.« less

A dynamic T cell–limited checkpoint regulates affinity-dependent B cell entry into the germinal center

PubMed Central

Schwickert, Tanja A.; Victora, Gabriel D.; Fooksman, David R.; Kamphorst, Alice O.; Mugnier, Monica R.; Gitlin, Alexander D.; Dustin, Michael L.

2011-01-01

The germinal center (GC) reaction is essential for the generation of the somatically hypermutated, high-affinity antibodies that mediate adaptive immunity. Entry into the GC is limited to a small number of B cell clones; however, the process by which this limited number of clones is selected is unclear. In this study, we demonstrate that low-affinity B cells intrinsically capable of seeding a GC reaction fail to expand and become activated in the presence of higher-affinity B cells even before GC coalescence. Live multiphoton imaging shows that selection is based on the amount of peptide–major histocompatibility complex (pMHC) presented to cognate T cells within clusters of responding B and T cells at the T–B border. We propose a model in which T cell help is restricted to the B cells with the highest amounts of pMHC, thus allowing for a dynamic affinity threshold to be imposed on antigen-binding B cells. PMID:21576382

Towards depersonalized abacavir therapy: chemical modification eliminates HLA-B*57 : 01-restricted CD8+ T-cell activation.

PubMed

Naisbitt, Dean J; Yang, Emma L; Alhaidari, Mohammad; Berry, Neil G; Lawrenson, Alexandre S; Farrell, John; Martin, Philip; Strebel, Klaus; Owen, Andrew; Pye, Matthew; French, Neil S; Clarke, Stephen E; O'Neill, Paul M; Park, B Kevin

2015-11-28

Exposure to abacavir is associated with T-cell-mediated hypersensitivity reactions in individuals carrying human leukocyte antigen (HLA)-B57 : 01. To activate T cells, abacavir interacts directly with endogenous HLA-B57 : 01 and HLA-B57 : 01 expressed on the surface of antigen presenting cells. We have investigated whether chemical modification of abacavir can produce a molecule with antiviral activity that does not bind to HLA-B57 : 01 and activate T cells. An interdisciplinary laboratory study using samples from human donors expressing HLA-B57 : 01. Researchers were blinded to the analogue structures and modelling data. Sixteen 6-amino substituted abacavir analogues were synthesized. Computational docking studies were completed to predict capacity for analogue binding within HLA-B57 : 01. Abacavir-responsive CD8 clones were generated to study the association between HLA-B57 : 01 analogue binding and T-cell activation. Antiviral activity and the direct inhibitory effect of analogues on proliferation were assessed. Major histocompatibility complex class I-restricted CD8 clones proliferated and secreted IFNγ following abacavir binding to surface and endogenous HLA-B57 : 01. Several analogues retained antiviral activity and showed no overt inhibitory effect on proliferation, but displayed highly divergent antigen-driven T-cell responses. For example, abacavir and N-propyl abacavir were equally potent at activating clones, whereas the closely related analogues N-isopropyl and N-methyl isopropyl abacavir were devoid of T-cell activity. Docking abacavir analogues to HLA-B57 : 01 revealed a quantitative relationship between drug-protein binding and the T-cell response. These studies demonstrate that the unwanted T-cell activity of abacavir can be eliminated whilst maintaining the favourable antiviral profile. The in-silico model provides a tool to aid the design of safer antiviral agents that may not require a personalized medicines approach to therapy.

T-dependence of human B lymphocyte proliferative response to mitogens.

PubMed

Brochier, J; Samarut, C; Gueho, J P; Revillard, J P

1976-01-01

Human peripheral blood and tonsil lymphocytes were fractionated on anti-Ig-coated Sephadex columns or by centrifugation after rosetting with native sheep erythrocytes. Both methods allowed the recovery of B and T-enriched populations the purity of which was checked by fluorescein-labelled anti-Ig serum, E and EAC rosette formation, and heterologous antisera specific for B or T lymphocytes. The proliferative response of T cells to PHA, Con A, PWM, and ALS was not found different from that of unfractionated cells, whereas no response of the B cells could be observed to these mitogens providing that no contaminating T cells were present. Addition of T lymphocytes to these unresponsive B cells allowed them to respond to phytomitogens, but not to ALS. X-irradiated T cells could, to some extent, replace the diving T lymphocytes; no T-replacing factor could be found in cell-free supernatants from T cells, whether or not they had been activated by mitrogens. This model of B-T cooperation appears useful for studying the differentiation and maturation of human B lymphocytes.

Critical role of SAP in progression and reactivation but not maintenance of T cell-dependent humoral immunity.

PubMed

Zhong, Ming-Chao; Veillette, André

2013-03-01

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is a small adaptor molecule mutated in X-linked lymphoproliferative disease, a human immunodeficiency. SAP plays a critical role in the initiation of T cell-dependent B cell responses leading to germinal center reaction, the production of high-affinity antibodies, and B cell memory. However, whether SAP has a role in these responses beyond their initiation is not known. It is important to address this matter not only for mechanistic reasons but also because blockade of the SAP pathway is being contemplated as a means to treat autoimmune diseases in humans. Using an inducibly SAP deficient mouse, we found that SAP was required not only for the initiation but also for the progression of primary T cell-driven B cell responses to haptens. It was also necessary for the reactivation of T cell-dependent B cell immunity during secondary immune responses. These activities consistently correlated with the requirement of SAP for full expression of the lineage commitment factor Bcl-6 in follicular T helper (T(FH)) cells. However, once memory B cells and long-lived antibody-secreting cells were established, SAP became dispensable for maintaining T cell-dependent B cell responses. Thus, SAP is pivotal for nearly all phases, but not for maintenance, of T cell-driven B cell humoral immunity. These findings may have implications for the treatment of immune disorders by targeting the SAP pathway.

Critical Role of SAP in Progression and Reactivation but Not Maintenance of T Cell-Dependent Humoral Immunity

PubMed Central

2013-01-01

Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) is a small adaptor molecule mutated in X-linked lymphoproliferative disease, a human immunodeficiency. SAP plays a critical role in the initiation of T cell-dependent B cell responses leading to germinal center reaction, the production of high-affinity antibodies, and B cell memory. However, whether SAP has a role in these responses beyond their initiation is not known. It is important to address this matter not only for mechanistic reasons but also because blockade of the SAP pathway is being contemplated as a means to treat autoimmune diseases in humans. Using an inducibly SAP deficient mouse, we found that SAP was required not only for the initiation but also for the progression of primary T cell-driven B cell responses to haptens. It was also necessary for the reactivation of T cell-dependent B cell immunity during secondary immune responses. These activities consistently correlated with the requirement of SAP for full expression of the lineage commitment factor Bcl-6 in follicular T helper (TFH) cells. However, once memory B cells and long-lived antibody-secreting cells were established, SAP became dispensable for maintaining T cell-dependent B cell responses. Thus, SAP is pivotal for nearly all phases, but not for maintenance, of T cell-driven B cell humoral immunity. These findings may have implications for the treatment of immune disorders by targeting the SAP pathway. PMID:23319045

IL-7–dependent STAT1 activation limits homeostatic CD4+ T cell expansion

PubMed Central

Le Saout, Cecile; Luckey, Megan A.; Villarino, Alejandro V.; Smith, Mindy; Hasley, Rebecca B.; Myers, Timothy G.; Imamichi, Hiromi; Park, Jung-Hyun; O’Shea, John J.; Lane, H. Clifford

2017-01-01

IL-7 regulates homeostatic mechanisms that maintain the overall size of the T cell pool throughout life. We show that, under steady-state conditions, IL-7 signaling is principally mediated by activation of signal transducers and activators of transcription 5 (STAT5). In contrast, under lymphopenic conditions, there is a modulation of STAT1 expression resulting in an IL-7–dependent STAT1 and STAT5 activation. Consequently, the IL-7–induced transcriptome is altered with enrichment of IFN-stimulated genes (ISGs). Moreover, STAT1 overexpression was associated with reduced survival in CD4+ T cells undergoing lymphopenia-induced proliferation (LIP). We propose a model in which T cells undergoing LIP upregulate STAT1 protein, “switching on” an alternate IL-7–dependent program. This mechanism could be a physiological process to regulate the expansion and size of the CD4+ T cell pool. During HIV infection, the virus could exploit this pathway, leading to the homeostatic dysregulation of the T cell pools observed in these patients. PMID:29202461

T-cells from HLA-B*57:01+ human subjects are activated with abacavir through two independent pathways and induce cell death by multiple mechanisms.

PubMed

Bell, Catherine C; Faulkner, Lee; Martinsson, Klara; Farrell, John; Alfirevic, Ana; Tugwood, Jonathan; Pirmohamed, Munir; Naisbitt, Dean J; Park, B Kevin

2013-05-20

Susceptibility to abacavir hypersensitivity has been attributed to possession of the specific human leukocyte antigen allele HLA-B*57:01. HLA-B*57:01-restricted activation of CD8+ T-cells provides a link between the genetic association and the iatrogenic disease. The objectives of this study were to characterize the functionality of drug-responsive CD8+ T-cell clones generated from HLA-B*57:01+ drug-naive subjects and to explore the relationship between abacavir accumulation in antigen presenting cells and the T-cell response. Seventy-four CD8+ clones expressing different Vβ receptors were shown to proliferate and kill target cells via different mechanisms when exposed to abacavir. Certain clones were activated with abacavir in the absence of antigen presenting cells. Analysis of the remaining clones revealed two pathways of drug-dependent T-cell activation. Overnight incubation of antigen presenting cells with abacavir, followed by repeated washing to remove soluble drug, activated approximately 50% of the clones, and the response was blocked by glutaraldehyde fixation. In contrast, a 1 h antigen presenting cell pulse did not activate any of the clones. Accumulation of abacavir in antigen presenting cells was rapid (less than 1 h), and the intracellular concentrations were maintained for 16 h. However, intracellular abacavir was not detectable by mass spectrometry after pulsing. These data suggest that T-cells can be activated by abacavir through a direct interaction with surface and intracellular major histocompatibility complex (MHC) molecules. With the former, abacavir seemingly participates in the MHC T-cell receptor binding interaction. In contrast, the latter pathway likely involves MHC binding peptides displayed as a consequence of abacavir exposure, but not abacavir itself.

[Regulatory B cells activated by CpG-ODN combined with anti-CD40 monoclonal antibody inhibit CD4(+)T cell proliferation].

PubMed

Wang, Keng; Tao, Lei; Su, Jianbing; Zhang, Yueyang; Zou, Binhua; Wang, Yiyuan; Li, Xiaojuan

2016-09-01

Objective To observe the immunosuppressive function of regulatory B cells (Bregs) in vitro after activated by CpG oligodeoxynucleotide (CpG-ODN) and anti-CD40 mAb. Methods Mice splenic CD5(+)CD1d(high)B cells and CD5(-)CD1d(low)B cells were sorted by flow cytometry. These B cells were first stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours, and then co-cultured with purified CD4(+)T cells. The interleukin 10 (IL-10) expression in the activated Bregs and other B cell subset, as well as the proliferation and interferon γ (IFN-γ) expression in the CD4(+) T cells activated by anti-CD3 mAb plus anti-CD28 mAb were determined by flow cytometry. Results CD5(+)CD1d(high) B cells activated by CpG-ODN plus anti-CD40 mAb blocked the up-regulated CD4(+)T proliferation and significantly reduced the IFN-γ level. At the same time, activated CD5(-)CD1d(low)B cells showed no inhibitory effect on CD4(+)T cells. Further study revealed that IL-10 expression in the CD5(+)CD1d(high) B cells were much higher than that in the CD5(-)CD1d(low)B cells after stimulated with CpG-ODN combined with anti-CD40 mAb for 24 hours. Conclusion CD5(+)CD1d(high) B cells activated by CpG-ODN combined with anti-CD40 mAb have immune inhibitory effects on CD4(+)T cell activation in vitro , which possibly due to IL-10 secretion.

Tolerance induction of IgG+ memory B cells by T cell-independent type II antigens.

PubMed

Haniuda, Kei; Nojima, Takuya; Ohyama, Kyosuke; Kitamura, Daisuke

2011-05-15

Memory B cells generated during a T cell-dependent immune response rapidly respond to a secondary immunization by producing abundant IgG Abs that bind cognate Ag with high affinity. It is currently unclear whether this heightened recall response by memory B cells is due to augmented IgG-BCR signaling, which has only been demonstrated in the context of naive transgenic B cells. To address this question, we examined whether memory B cells can respond in vivo to Ags that stimulate only through BCR, namely T cell-independent type II (TI-II) Ags. In this study, we show that the TI-II Ag (4-hydroxy-3-nitrophenyl) acetyl (NP)-Ficoll cannot elicit the recall response in mice first immunized with the T cell-dependent Ag NP-chicken γ-globulin. Moreover, the NP-Ficoll challenge in vivo as well as in vitro significantly inhibits a subsequent recall response to NP-chicken γ-globulin in a B cell-intrinsic manner. This NP-Ficoll-mediated tolerance is caused by the preferential elimination of IgG(+) memory B cells binding to NP with high affinity. These data indicate that BCR cross-linking with a TI-II Ag does not activate IgG(+) memory B cells, but rather tolerizes them, identifying a terminal checkpoint of memory B cell differentiation that may prevent autoimmunity.

T-cell receptor signaling activates an ITK/NF-κB/GATA-3 axis in T-cell lymphomas facilitating resistance to chemotherapy

PubMed Central

Wang, Tianjiao; Lu, Ye; Polk, Avery; Chowdhury, Pinki; Zamalloa, Carlos Murga; Fujiwara, Hiroshi; Suemori, Koichiro; Beyersdorf, Niklas; Hristov, Alexandra C.; Lim, Megan S.; Bailey, Nathanael G.; Wilcox, Ryan A.

2016-01-01

Purpose T-cell lymphomas are a molecularly heterogeneous group of non-Hodgkin lymphomas (NHL) that account for a disproportionate number of NHL disease-related deaths due to their inherent and acquired resistance to standard multiagent chemotherapy regimens. Despite their molecular heterogeneity and frequent loss of various T-cell specific receptors, the T-cell antigen receptor is retained in the majority of these lymphomas. As T-cell receptor (TCR) engagement activates a number of signaling pathways and transcription factors that regulate T-cell growth and survival, we examined the TCR’s role in mediating resistance to chemotherapy. Experimental Design Genetic and pharmacologic strategies were utilized to determine the contribution of tyrosine kinases and transcription factors activated in conventional T cells following T-cell receptor (TCR) engagement in acquired chemotherapy resistance in primary T-cell lymphoma cells and patient-derived cell lines. Results Here we report that TCR signaling activates a signaling axis that includes ITK, NF-κB, and GATA-3, and promotes chemotherapy resistance. Conclusions These observations have significant therapeutic implications, as pharmacologic inhibition of ITK prevented activation of this signaling axis and overcame chemotherapy resistance. PMID:27780854

EBV induces persistent NF-κB activation and contributes to survival of EBV-positive neoplastic T- or NK-cells.

PubMed

Takada, Honami; Imadome, Ken-Ichi; Shibayama, Haruna; Yoshimori, Mayumi; Wang, Ludan; Saitoh, Yasunori; Uota, Shin; Yamaoka, Shoji; Koyama, Takatoshi; Shimizu, Norio; Yamamoto, Kouhei; Fujiwara, Shigeyoshi; Miura, Osamu; Arai, Ayako

2017-01-01

Epstein-Barr virus (EBV) has been detected in several T- and NK-cell neoplasms such as extranodal NK/T-cell lymphoma nasal type, aggressive NK-cell leukemia, EBV-positive peripheral T-cell lymphoma, systemic EBV-positive T-cell lymphoma of childhood, and chronic active EBV infection (CAEBV). However, how this virus contributes to lymphomagenesis in T or NK cells remains largely unknown. Here, we examined NF-κB activation in EBV-positive T or NK cell lines, SNT8, SNT15, SNT16, SNK6, and primary EBV-positive and clonally proliferating T/NK cells obtained from the peripheral blood of patients with CAEBV. Western blotting, electrophoretic mobility shift assays, and immunofluorescent staining revealed persistent NF-κB activation in EBV-infected cell lines and primary cells from patients. Furthermore, we investigated the role of EBV in infected T cells. We performed an in vitro infection assay using MOLT4 cells infected with EBV. The infection directly induced NF-κB activation, promoted survival, and inhibited etoposide-induced apoptosis in MOLT4 cells. The luciferase assay suggested that LMP1 mediated NF-κB activation in MOLT4 cells. IMD-0354, a specific inhibitor of NF-κB that suppresses NF-κB activation in cell lines, inhibited cell survival and induced apoptosis. These results indicate that EBV induces NF-κB-mediated survival signals in T and NK cells, and therefore, may contribute to the lymphomagenesis of these cells.

EBV induces persistent NF-κB activation and contributes to survival of EBV-positive neoplastic T- or NK-cells

PubMed Central

Shibayama, Haruna; Yoshimori, Mayumi; Wang, Ludan; Saitoh, Yasunori; Uota, Shin; Yamaoka, Shoji; Koyama, Takatoshi; Shimizu, Norio; Yamamoto, Kouhei; Fujiwara, Shigeyoshi; Miura, Osamu

2017-01-01

Epstein–Barr virus (EBV) has been detected in several T- and NK-cell neoplasms such as extranodal NK/T-cell lymphoma nasal type, aggressive NK-cell leukemia, EBV-positive peripheral T-cell lymphoma, systemic EBV-positive T-cell lymphoma of childhood, and chronic active EBV infection (CAEBV). However, how this virus contributes to lymphomagenesis in T or NK cells remains largely unknown. Here, we examined NF-κB activation in EBV-positive T or NK cell lines, SNT8, SNT15, SNT16, SNK6, and primary EBV-positive and clonally proliferating T/NK cells obtained from the peripheral blood of patients with CAEBV. Western blotting, electrophoretic mobility shift assays, and immunofluorescent staining revealed persistent NF-κB activation in EBV-infected cell lines and primary cells from patients. Furthermore, we investigated the role of EBV in infected T cells. We performed an in vitro infection assay using MOLT4 cells infected with EBV. The infection directly induced NF-κB activation, promoted survival, and inhibited etoposide-induced apoptosis in MOLT4 cells. The luciferase assay suggested that LMP1 mediated NF-κB activation in MOLT4 cells. IMD-0354, a specific inhibitor of NF-κB that suppresses NF-κB activation in cell lines, inhibited cell survival and induced apoptosis. These results indicate that EBV induces NF-κB-mediated survival signals in T and NK cells, and therefore, may contribute to the lymphomagenesis of these cells. PMID:28346502

NF-κB signaling mechanisms in HTLV-1-induced adult T-cell leukemia/lymphoma.

PubMed

Harhaj, Edward William; Giam, Chou-Zen

2018-05-03

The human T-cell leukemia virus type 1 (HTLV-1) is a complex deltaretrovirus linked to adult T-cell leukemia/lymphoma (ATLL), a fatal CD4+ malignancy in 3-5% of infected individuals. The HTLV-1 Tax regulatory protein plays indispensable roles in regulating viral gene expression and activating cellular signaling pathways that drive the proliferation and clonal expansion of T cells bearing HTLV-1 proviral integrations. Tax is a potent activator of NF-κB, a key signaling pathway that is essential for the survival and proliferation of HTLV-1 infected T cells. However, constitutive NF-κB activation by Tax also triggers a senescence response, suggesting the possibility that only T cells capable of overcoming NF-κB-induced senescence can selectively undergo clonal expansion after HTLV-1 infection. Tax expression is often silenced in the majority of ATLL due to genetic alterations in the tax gene or DNA hypermethylation of the 5'-LTR. Despite the loss of Tax, NF-κB activation remains persistently activated in ATLL due to somatic mutations in genes in the T/B-cell receptor (T/BCR) and NF-κB signaling pathways. In this review, we focus on the key events driving Tax-dependent and independent mechanisms of NF-κB activation during the multi-step process leading to ATLL. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

PubMed

Xu, Hui; Yan, Yaping; Williams, Mark S; Carey, Gregory B; Yang, Jingxian; Li, Hongmei; Zhang, Guang-Xian; Rostami, Abdolmohamad

2010-11-01

MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK) and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

Coxiella burnetii Avirulent Nine Mile Phase II Induces Caspase-1-Dependent Pyroptosis in Murine Peritoneal B1a B Cells.

PubMed

Schoenlaub, Laura; Cherla, Rama; Zhang, Yan; Zhang, Guoquan

2016-12-01

Our recent study demonstrated that virulent Coxiella burnetii Nine Mile phase I (NMI) is capable of infecting and replicating within peritoneal B1a cells and that B1a cells play an important role in host defense against C. burnetii infection in mice. However, it remains unknown if avirulent Nine Mile phase II (NMII) can infect and replicate in B1a cells and whether NMI and NMII can differentially interact with B1a cells. In this study, we examined if NMI and NMII can differentially modulate host cell apoptotic signaling in B1a cells. The results showed that NMII induced dose-dependent cell death in murine peritoneal B1a cells but NMI did not, suggesting that NMI and NMII may differentially activate host cell apoptotic signaling in B1a cells. Western blotting indicated that NMII-induced B1a cell death was not dependent on either caspase-3 or PARP-1 cleavage, but cleavage of caspase-1 was detected in NMII-infected B1a cells. In addition, inhibition or deficiency of caspase-1 activity blocked NMII-induced B1a cell death. These results suggest that NMII induces a caspase-1-dependent pyroptosis in murine peritoneal B1a cells. We also found that heat-killed NMII and type 4 secretion system (T4SS) mutant NMII were unable to induce B1a cell death and that NMII infection did not induce cell death in peritoneal B1a cells from Toll-like receptor 2 (TLR-2)- or NLRP3 inflammasome-deficient mice. These data suggest that NMII-induced caspase-1-dependent pyroptosis may require its T4SS and activation of the TLR-2 and NLRP3 signaling pathways. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Molecular mechanisms of programmed cell death-1 dependent T cell suppression: relevance for immunotherapy

PubMed Central

Zuazo, Miren; Gato-Cañas, Maria; Llorente, Noelia; Ibañez-Vea, María; Arasanz, Hugo

2017-01-01

Programmed cell death-1 (PD1) has become a significant target for cancer immunotherapy. PD1 and its receptor programmed cell death 1 ligand 1 (PDL1) are key regulatory physiological immune checkpoints that maintain self-tolerance in the organism by regulating the degree of activation of T and B cells amongst other immune cell types. However, cancer cells take advantage of these immunosuppressive regulatory mechanisms to escape T and B cell-mediated immunity. PD1 engagement on T cells by PDL1 on the surface of cancer cells dramatically interferes with T cell activation and the acquisition of effector capacities. Interestingly, PD1-targeted therapies have demonstrated to be highly effective in rescuing T cell anti-tumor effector functions. Amongst these the use of anti-PD1/PDL1 monoclonal antibodies are particularly efficacious in human therapies. Furthermore, clinical findings with PD1/PDL1 blockers over several cancer types demonstrate clinical benefit. Despite the successful results, the molecular mechanisms by which PD1-targeted therapies rescue T cell functions still remain elusive. Therefore, it is a key issue to uncover the molecular pathways by which these therapies exert its function in T cells. A profound knowledge of PDL1/PD1 mechanisms will surely uncover a new array of targets susceptible of therapeutic intervention. Here, we provide an overview of the molecular events underlying PD1-dependent T cell suppression in cancer. PMID:29114543

Basal shuttle of NF-κB/IκBα in resting T lymphocytes regulates HIV-1 LTR dependent expression

PubMed Central

Coiras, Mayte; López-Huertas, María Rosa; Rullas, Joaquín; Mittelbrunn, Maria; Alcamí, José

2007-01-01

Background In HIV-infected T lymphocytes, NF-κB/Rel transcription factors are major elements involved in the activation of LTR-dependent transcription from latency. Most NF-κB heterodimer p65/p50 is sequestered as an inactive form in the cytoplasm of resting T lymphocytes via its interaction with IκB inhibitors. In these cells, both absolute HIV latency and low level ongoing HIV replication have been described. These situations could be related to differences in the balance between NF-κB and IκBα ratio. Actually, control of IκBα by cellular factors such as Murr-1 plays a critical role in maintaining HIV latency in unstimulated T lymphocytes. Formerly, our group demonstrated the presence of nuclear IκBα in T cells after PMA activation. Now we attempt to determine the dynamics of NF-κB/IκBα nucleocytosolic transport in absence of activation as a mechanism to explain both the maintenance of latency and the existence of low level ongoing HIV replication in resting CD4+ T lymphocytes. Results and conclusion We show that the inhibition of the nuclear export by leptomycin B in resting CD4+ T cells resulted in nuclear accumulation of both IκBα and p65/RelA, as well as formation of NF-κB/IκBα complexes. This proves the existence of a rapid shuttling of IκBα between nucleus and cytosol even in absence of cellular activation. The nuclear accumulation of IκBα in resting CD4+ T lymphocytes results in inhibition of HIV-LTR dependent transcription as well as restrains HIV replication in CD4+ T lymphocytes. On the other hand, basal NF-κB activity detected in resting CD4+ T lymphocytes was related to low level HIV replication in these cells. PMID:17686171

Mechanisms of B cell activation in patients with acquired immunodeficiency syndrome and related disorders. Contribution of antibody-producing B cells, of Epstein-Barr virus-infected B cells, and of immunoglobulin production induced by human T cell lymphotropic virus, type III/lymphadenopathy-associated virus.

PubMed Central

Yarchoan, R; Redfield, R R; Broder, S

1986-01-01

Patients with acquired immunodeficiency syndrome (AIDS) and AIDS-related complex (ARC) have hyperimmunoglobulinemia and increased numbers of circulating immunoglobulin-secreting cells. In this paper, we studied the basis for this B cell hyperactivity. Limiting dilution studies of B cells from seven patients with ARC and four with AIDS revealed that some B cells spontaneously produced antibodies to human T cell lymphotropic virus, type III/lymphadenopathy-associated virus (HTLV-III/LAV) (39:10(6) and 7:10(6) B cells, respectively), suggesting that chronic antigenic stimulation by HTLV-III/LAV was one contributing factor. The patients also had an increased number of spontaneously outgrowing B cells than did normals (6:10(6) vs. less than 2:10(6) B cells), suggesting that they had an increased number of Epstein-Barr virus (EBV)-infected B cells. However, fewer B cells from patients were immortalized by exogenously added EBV than were B cells from normals. In additional studies, HTLV-III/LAV induced immunoglobulin secretion (mean 2,860 ng/ml) by peripheral blood mononuclear cells from normals; this HTLV-III/LAV-induced immunoglobulin secretion required the presence of both B and T cells. Thus, antigenic stimulation by HTLV-III/LAV, increased numbers of EBV-infected B cells, and HTLV-III/LAV-induced T cell-dependent B cell activation all contribute to the B cell hyperactivity in patients with HTLV-III/LAV disease. PMID:3016028

Mast cells enhance T cell activation: Importance of mast cell-derived TNF

NASA Astrophysics Data System (ADS)

Nakae, Susumu; Suto, Hajime; Kakurai, Maki; Sedgwick, Jonathon D.; Tsai, Mindy; Galli, Stephen J.

2005-05-01

Mast cells are not only important effector cells in immediate hypersensitivity reactions and immune responses to pathogens but also can contribute to T cell-mediated disorders. However, the mechanisms by which mast cells might influence T cells in such settings are not fully understood. We find that mast cells can enhance proliferation and cytokine production in multiple T cell subsets. Mast cell-dependent enhancement of T cell activation can be promoted by FcRI-dependent mast cell activation, TNF production by both mast cells and T cells, and mast cell-T cell contact. However, at high concentrations of cells, mast cells can promote T cell activation independent of IgE or TNF. Finally, mast cells also can promote T cell activation by means of soluble factors. These findings identify multiple mechanisms by which mast cells can influence T cell proliferation and cytokine production. allergy | asthma | autoimmunity | cytokines | immune response

Oxaliplatin antagonizes HIV-1 latency by activating NF-κB without causing global T cell activation

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

Zhu, Xiaoli; Liu, Sijie; Wang, Pengfei

Highlights: • The chemotherapeutic drug oxaliplatin reactivates latent HIV-1 in this cell line model of HIV-1 latency. • Reactivation is synergized when oxaliplatin is used in combination with valproic acid. • Oxaliplatin reactivates latent HIV-1 through activation of NF-kB and does not induce T cell activation. - Abstract: Reactivation of latent HIV-1 is a promising strategy for the clearance of the viral reservoirs. Because of the limitations of current agents, identification of new latency activators is urgently required. Using an established model of HIV-1 latency, we examined the effect of Oxaliplatin on latent HIV-1 reactivation. We showed that Oxaliplatin, alonemore » or in combination with valproic acid (VPA), was able to reactivate HIV-1 without inducing global T cell activation. We also provided evidence that Oxaliplatin reactivated HIV-1 expression by inducing nuclear factor kappa B (NF-κB) nuclear translocation. Our results indicated that Oxaliplatin could be a potential drug candidate for anti-latency therapies.« less

T-cell Receptor Signaling Activates an ITK/NF-κB/GATA-3 axis in T-cell Lymphomas Facilitating Resistance to Chemotherapy.

PubMed

Wang, Tianjiao; Lu, Ye; Polk, Avery; Chowdhury, Pinki; Zamalloa, Carlos Murga; Fujiwara, Hiroshi; Suemori, Koichiro; Beyersdorf, Niklas; Hristov, Alexandra C; Lim, Megan S; Bailey, Nathanael G; Wilcox, Ryan A

2017-05-15

Purpose: T-cell lymphomas are a molecularly heterogeneous group of non-Hodgkin lymphomas (NHL) that account for a disproportionate number of NHL disease-related deaths due to their inherent and acquired resistance to standard multiagent chemotherapy regimens. Despite their molecular heterogeneity and frequent loss of various T cell-specific receptors, the T-cell antigen receptor is retained in the majority of these lymphomas. As T-cell receptor (TCR) engagement activates a number of signaling pathways and transcription factors that regulate T-cell growth and survival, we examined the TCR's role in mediating resistance to chemotherapy. Experimental Design: Genetic and pharmacologic strategies were utilized to determine the contribution of tyrosine kinases and transcription factors activated in conventional T cells following TCR engagement in acquired chemotherapy resistance in primary T-cell lymphoma cells and patient-derived cell lines. Results: Here, we report that TCR signaling activates a signaling axis that includes ITK, NF-κB, and GATA-3 and promotes chemotherapy resistance. Conclusions: These observations have significant therapeutic implications, as pharmacologic inhibition of ITK prevented the activation of this signaling axis and overcame chemotherapy resistance. Clin Cancer Res; 23(10); 2506-15. ©2016 AACR . ©2016 American Association for Cancer Research.

Identification of transcription coactivator OCA-B-dependent genes involved in antigen-dependent B cell differentiation by cDNA array analyses.

PubMed

Kim, Unkyu; Siegel, Rachael; Ren, Xiaodi; Gunther, Cary S; Gaasterland, Terry; Roeder, Robert G

2003-07-22

The tissue-specific transcriptional coactivator OCA-B is required for antigen-dependent B cell differentiation events, including germinal center formation. However, the identity of OCA-B target genes involved in this process is unknown. This study has used large-scale cDNA arrays to monitor changes in gene expression patterns that accompany mature B cell differentiation. B cell receptor ligation alone induces many genes involved in B cell expansion, whereas B cell receptor and helper T cell costimulation induce genes associated with B cell effector function. OCA-B expression is induced by both B cell receptor ligation alone and helper T cell costimulation, suggesting that OCA-B is involved in B cell expansion as well as B cell function. Accordingly, several genes involved in cell proliferation and signaling, such as Lck, Kcnn4, Cdc37, cyclin D3, B4galt1, and Ms4a11, have been identified as OCA-B-dependent genes. Further studies on the roles played by these genes in B cells will contribute to an understanding of B cell differentiation.

CD95 co-stimulation blocks activation of naive T cells by inhibiting T cell receptor signaling

PubMed Central

Lindquist, Jonathan A.; Arhel, Nathalie; Felder, Edward; Karl, Sabine; Haas, Tobias L.; Fulda, Simone; Walczak, Henning; Kirchhoff, Frank; Debatin, Klaus-Michael

2009-01-01

CD95 is a multifunctional receptor that induces cell death or proliferation depending on the signal, cell type, and cellular context. Here, we describe a thus far unknown function of CD95 as a silencer of T cell activation. Naive human T cells triggered by antigen-presenting cells expressing a membrane-bound form of CD95 ligand (CD95L) or stimulated by anti-CD3 and -CD28 antibodies in the presence of recombinant CD95L had reduced activation and proliferation, whereas preactivated, CD95-sensitive T cells underwent apoptosis. Triggering of CD95 during T cell priming interfered with proximal T cell receptor signaling by inhibiting the recruitment of ζ-chain–associated protein of 70 kD, phospholipase-γ, and protein kinase C-θ into lipid rafts, thereby preventing their mutual tyrosine protein phosphorylation. Subsequently, Ca2+ mobilization and nuclear translocation of transcription factors NFAT, AP1, and NF-κB were strongly reduced, leading to impaired cytokine secretion. CD95-mediated inhibition of proliferation in naive T cells could not be reverted by the addition of exogenous interleukin-2 and T cells primed by CD95 co-stimulation remained partially unresponsive upon secondary T cell stimulation. HIV infection induced CD95L expression in primary human antigeen-presenting cells, and thereby suppressed T cell activation, suggesting that CD95/CD95L-mediated silencing of T cell activation represents a novel mechanism of immune evasion. PMID:19487421

Human T-Cell Leukemia Virus Type 1 Tax Induction of NF-κB Involves Activation of the IκB Kinase α (IKKα) and IKKβ Cellular Kinases

PubMed Central

Geleziunas, Romas; Ferrell, Sharon; Lin, Xin; Mu, Yajun; Cunningham, Emmett T.; Grant, Mark; Connelly, Margery A.; Hambor, John E.; Marcu, Kenneth B.; Greene, Warner C.

1998-01-01

Tax corresponds to a 40-kDa transforming protein from the pathogenic retrovirus human T-cell leukemia virus type 1 (HTLV-1) that activates nuclear expression of the NF-κB/Rel family of transcription factors by an unknown mechanism. Tax expression promotes N-terminal phosphorylation and degradation of IκBα, a principal cytoplasmic inhibitor of NF-κB. Our studies now demonstrate that HTLV-1 Tax activates the recently identified cellular kinases IκB kinase α (IKKα) and IKKβ, which normally phosphorylate IκBα on both of its N-terminal regulatory serines in response to tumor necrosis factor alpha (TNF-α) and interleukin-1 (IL-1) stimulation. In contrast, a mutant of Tax termed M22, which does not induce NF-κB, fails to activate either IKKα or IKKβ. Furthermore, endogenous IKK enzymatic activity was significantly elevated in HTLV-1-infected and Tax-expressing T-cell lines. Transfection of kinase-deficient mutants of IKKα and IKKβ into either human Jurkat T or 293 cells also inhibits NF-κB-dependent reporter gene expression induced by Tax. Similarly, a kinase-deficient mutant of NIK (NF-κB-inducing kinase), which represents an upstream kinase in the TNF-α and IL-1 signaling pathways leading to IKKα and IKKβ activation, blocks Tax induction of NF-κB. However, plasma membrane-proximal elements in these proinflammatory cytokine pathways are apparently not involved since dominant negative mutants of the TRAF2 and TRAF6 adaptors, which effectively block signaling through the cytoplasmic tails of the TNF-α and IL-1 receptors, respectively, do not inhibit Tax induction of NF-κB. Together, these studies demonstrate that HTLV-1 Tax exploits a distal part of the proinflammatory cytokine signaling cascade leading to induction of NF-κB. The pathological alteration of this cytokine pathway leading to NF-κB activation by Tax may play a central role in HTLV-1-mediated transformation of human T cells, clinically manifested as the adult T-cell leukemia. PMID

Cathepsin B-Deficient Mice Resolve Leishmania major Inflammation Faster in a T Cell-Dependent Manner

PubMed Central

Mériaux, Véronique; Khan, Erin M.; Borde, Chloé; Ciulean, Ioana S.; Fitting, Catherine; Manoury, Bénédicte; Cavaillon, Jean-Marc; Doyen, Noëlle

2016-01-01

A critical role for intracellular TLR9 has been described in recognition and host resistance to Leishmania parasites. As TLR9 requires endolysosomal proteolytic cleavage to achieve signaling functionality, we investigated the contribution of different proteases like asparagine endopeptidase (AEP) or cysteine protease cathepsins B (CatB), L (CatL) and S (CatS) to host resistance during Leishmania major (L. major) infection in C57BL/6 (WT) mice and whether they would impact on TLR9 signaling. Unlike TLR9-/-, which are more susceptible to infection, AEP-/-, CatL-/- and CatS-/- mice are as resistant to L. major infection as WT mice, suggesting that these proteases are not individually involved in TLR9 processing. Interestingly, we observed that CatB-/- mice resolve L. major lesions significantly faster than WT mice, however we did not find evidence for an involvement of CatB on either TLR9-dependent or independent cytokine responses of dendritic cells and macrophages or in the innate immune response to L. major infection. We also found no difference in antigen presenting capacity. We observed a more precocious development of T helper 1 responses accompanied by a faster decline of inflammation, resulting in resolution of footpad inflammation, reduced IFNγ levels and decreased parasite burden. Adoptive transfer experiments into alymphoid RAG2-/-γc-/- mice allowed us to identify CD3+ T cells as responsible for the immune advantage of CatB-/- mice towards L. major. In vitro data confirmed the T cell intrinsic differences between CatB-/- mice and WT. Our study brings forth a yet unappreciated role for CatB in regulating T cell responses during L. major infection. PMID:27182703

Magnetic Field-Induced T Cell Receptor Clustering by Nanoparticles Enhances T Cell Activation and Stimulates Antitumor Activity

PubMed Central

2015-01-01

Iron–dextran nanoparticles functionalized with T cell activating proteins have been used to study T cell receptor (TCR) signaling. However, nanoparticle triggering of membrane receptors is poorly understood and may be sensitive to physiologically regulated changes in TCR clustering that occur after T cell activation. Nano-aAPC bound 2-fold more TCR on activated T cells, which have clustered TCR, than on naive T cells, resulting in a lower threshold for activation. To enhance T cell activation, a magnetic field was used to drive aggregation of paramagnetic nano-aAPC, resulting in a doubling of TCR cluster size and increased T cell expansion in vitro and after adoptive transfer in vivo. T cells activated by nano-aAPC in a magnetic field inhibited growth of B16 melanoma, showing that this novel approach, using magnetic field-enhanced nano-aAPC stimulation, can generate large numbers of activated antigen-specific T cells and has clinically relevant applications for adoptive immunotherapy. PMID:24564881

Inactivation of p53 by Human T-Cell Lymphotropic Virus Type 1 Tax Requires Activation of the NF-κB Pathway and Is Dependent on p53 Phosphorylation

PubMed Central

Pise-Masison, Cynthia A.; Mahieux, Renaud; Jiang, Hua; Ashcroft, Margaret; Radonovich, Michael; Duvall, Janet; Guillerm, Claire; Brady, John N.

2000-01-01

p53 plays a key role in guarding cells against DNA damage and transformation. We previously demonstrated that the human T-cell lymphotropic virus type 1 (HTLV-1) Tax can inactivate p53 transactivation function in lymphocytes. The present study demonstrates that in T cells, Tax-induced p53 inactivation is dependent upon NF-κB activation. Analysis of Tax mutants demonstrated that Tax inactivation of p53 function correlates with the ability of Tax to induce NF-κB but not p300 binding or CREB transactivation. The Tax-induced p53 inactivation can be overcome by overexpression of a dominant IκB mutant. Tax-NF-κB-induced p53 inactivation is not due to p300 squelching, since overexpression of p300 does not recover p53 activity in the presence of Tax. Further, using wild-type and p65 knockout mouse embryo fibroblasts (MEFs), we demonstrate that the p65 subunit of NF-κB is critical for Tax-induced p53 inactivation. While Tax can inactivate endogenous p53 function in wild-type MEFs, it fails to inactivate p53 function in p65 knockout MEFs. Importantly, Tax-induced p53 inactivation can be restored by expression of p65 in the knockout MEFs. Finally, we present evidence that phosphorylation of serines 15 and 392 correlates with inactivation of p53 by Tax in T cells. This study provides evidence that the divergent NF-κB proliferative and p53 cell cycle arrest pathways may be cross-regulated at several levels, including posttranslational modification of p53. PMID:10779327

Induction of IgA B cell differentiation of bone marrow-derived B cells by Peyer's patch autoreactive helper T cells.

PubMed

Kihira, T; Kawanishi, H

1995-08-01

The objective of this study was to demonstrate in vitro that bone marrow-derived pro/pre-B cells bearing mu mRNA can switch their Ig heavy-chain isotype to that of alpha mRNA-expressing B cells after contact with Peyer's patches-derived activated autoreactive CD4+ T cells. Bone marrow-derived pro/pre-B cells and activated autoreactive Peyer's patch, mesenteric lymph node, or spleen CD4+ T cells were co-cultured in the presence of recombinant (r) IL-2, rIL-7, and Con A for 3 days. The mixed cultured cells were isolated for preparation of total RNA. Dot/slot hybridization, using murine C mu (pu3741) and C alpha (P alpha J558) Ig heavy-chain cDNA probes, detected C mu and C alpha Ig heavy-chain mRNA transcripts. The magnitude of each mRNA expression was measured demsitometrically. In addition, the secreted class-specific Ig contents from the co-cultured supernatants were measured. The results indicate that activated autoreactive Peyer's patch and mesenteric lymph node CD4+ T cells provide a specific Ig heavy-chain switch from mu to alpha (Peyer's patch CD4+ T cells > mesenteric lymph node CD4+ T cells) in bone marrow-derived pro/pre-B cells and also assist to develop IgA-secreting plasma cells. The alpha heavy-chain switch and IgA production do not occur in the presence of activated autoreactive spleen CD4+ T cells. These results support the view that autoreactive gut Peyer's patch CD4+ T cells, at least, regulate IgA B cell heavy-chain switching and terminal differentiation during gut mucosal B cell development.

Treating B-cell cancer with T cells expressing anti-CD19 chimeric antigen receptors.

PubMed

Kochenderfer, James N; Rosenberg, Steven A

2013-05-01

Most B-cell malignancies express CD19, and a majority of patients with B-cell malignancies are not cured by current standard therapies. Chimeric antigen receptors (CARs) are fusion proteins consisting of antigen recognition moieties and T-cell activation domains. T cells can be genetically modified to express CARs, and adoptive transfer of anti-CD19 CAR T cells is now being tested in clinical trials. Effective clinical treatment with anti-CD19 CAR T cells was first reported in 2010 after a patient with advanced-stage lymphoma treated at the NCI experienced a partial remission of lymphoma and long-term eradication of normal B cells. Additional patients have subsequently obtained long-term remissions of advanced-stage B-cell malignancies after infusions of anti-CD19 CAR T cells. Long-term eradication of normal CD19(+) B cells from patients receiving infusions of anti-CD19 CAR T cells demonstrates the potent antigen-specific activity of these T cells. Some patients treated with anti-CD19 CAR T cells have experienced acute adverse effects, which were associated with increased levels of serum inflammatory cytokines. Although anti-CD19 CAR T cells are at an early stage of development, the potent antigen-specific activity observed in patients suggests that infusions of anti-CD19 CAR T cells might become a standard therapy for some B-cell malignancies.

The role of Ia molecules in the activation of T lymphocytes. I. The activation of an IL 1-dependent IL 2-producing T cell hybridoma by Con A requires an interaction, which is not H-2-restricted, with an Ia-bearing accessory cell.

PubMed

Rock, K L

1982-10-01

A model of accessory cell-dependent lectin-mediated T cell activation was investigated by utilizing a mitogen-inducible T cell hybridoma. A continuous MHC-restricted antigen-specific T cell line was fused with the azaguanine-resistant AKR thymoma BW5147. A hybrid, RF1.16B, was identified that is minimally inducible by Con A stimulation alone but is stimulated by Con A in the presence of T cell-depleted accessory cells to produce interleukin 2. The accessory cell function can be replaced by the monokine interleukin 1. Thus the lectin is a sufficient trigger for the hybrid in the absence of MHC restriction elements. The accessory cell function from splenocytes is provided by a non-B, non-T, predominantly Ia-bearing radioresistant cell. The interaction between the RF1.16B hybrid and the accessory cell population is not H-2-restricted. Control experiments, including the use of a cloned source of accessory cells, ruled out contaminating T cells or direct lectin effects as an explanation for the lack of H-2 restriction. The finding that an Ia-bearing cell is required for activation in an MHC-nonrestricted manner is discussed, and a hypothesis is raised that Ia antigens may play a role in addition to that of being a restriction element.

Similar disturbances in B cell activity and regulatory T cell function in Henoch-Schonlein purpura and systemic lupus erythematosus

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

Beale, M.G.; Nash, G.S.; Bertovich, M.J.

1982-01-01

The immunoglobulin synthesizing activities of peripheral mononuclear cells (MNC) from five patients with Henoch-Schonlein purpura (HSP) and eight patients with active systemic lupus erythematosus (SLE) were compared. Cumulative amounts of IgM, IgG, and IgA synthesized and secreted by unstimulated and PWM-stimulated patient cells over a 12-day period were determied in a solid-phase radioimmunoassay. In unstimulated control cultures mean rates of IgM, IgG, and IgA synthesis were less than 250 ng/ml. The synthetic activities of patient MNC were markedly increased. In HSP cultures IgA was the major immunoglobulin class produced (2810 x/divide 1.33 ng/ml) followed by IgG (1754 x/divide 1.32 ng/ml)more » and IgM (404 x/divide 1.16 ng/ml). In SLE cultures IgA and IgG syntheses were equally elevated (4427 x/divide 1.20 and 4438 x/divide 1.49 ng/ml, respectively) whereas IgM synthesis averaged 967 x/divide 1.66 ng/ml. PWM stimulation of pateient MNC caused a sharp decline in the synthesis of all three immunoglobulin classes. After T cell depletion B cell-enriched fractions from HSP and SLE patients maintained high levels of IgA and IgG synthesis that were inhibited by PWM and by normal allogeneic but not autologous T cells. In PWM-stimulted co-cultures, patient T cells nonspecifically suppressed the synthetic activities of autologous and control B cells. in contrast patient B cells achieved normal levels of immunoglobulin synthesis when cultured with control T cells plus PWM. In longitudinal studies patient B and T cell disturbances persisted despite clinical improvement.« less

Surface receptor Toso controls B cell-mediated regulation of T cell immunity.

PubMed

Yu, Jinbo; Duong, Vu Huy Hoang; Westphal, Katrin; Westphal, Andreas; Suwandi, Abdulhadi; Grassl, Guntram A; Brand, Korbinian; Chan, Andrew C; Föger, Niko; Lee, Kyeong-Hee

2018-05-01

The immune system is tightly controlled by regulatory processes that allow for the elimination of invading pathogens, while limiting immunopathological damage to the host. In the present study, we found that conditional deletion of the cell surface receptor Toso on B cells unexpectedly resulted in impaired proinflammatory T cell responses, which led to impaired immune protection in an acute viral infection model and was associated with reduced immunopathological tissue damage in a chronic inflammatory context. Toso exhibited its B cell-inherent immunoregulatory function by negatively controlling the pool of IL-10-competent B1 and B2 B cells, which were characterized by a high degree of self-reactivity and were shown to mediate immunosuppressive activity on inflammatory T cell responses in vivo. Our results indicate that Toso is involved in the differentiation/maintenance of regulatory B cells by fine-tuning B cell receptor activation thresholds. Furthermore, we showed that during influenza A-induced pulmonary inflammation, the application of Toso-specific antibodies selectively induced IL-10-competent B cells at the site of inflammation and resulted in decreased proinflammatory cytokine production by lung T cells. These findings suggest that Toso may serve as a novel therapeutic target to dampen pathogenic T cell responses via the modulation of IL-10-competent regulatory B cells.

Constitutive CD40L Expression on B Cells Prematurely Terminates Germinal Center Response and Leads to Augmented Plasma Cell Production in T Cell Areas

PubMed Central

Bolduc, Anna; Long, Eugene; Stapler, Dale; Cascalho, Marilia; Tsubata, Takeshi; Koni, Pandelakis A.; Shimoda, Michiko

2013-01-01

CD40/CD40L engagement is essential to T cell-dependent B cell proliferation and differentiation. However, the precise role of CD40 signaling through cognate T–B interaction in the generation of germinal center and memory B cells is still incompletely understood. To address this issue, a B cell-specific CD40L transgene (CD40LBTg) was introduced into mice with B cell-restricted MHC class II deficiency. Using this mouse model, we show that constitutive CD40L expression on B cells alone could not induce germinal center differentiation of MHC class II-deficient B cells after immunization with T cell-dependent Ag. Thus, some other MHC class II-dependent T cell-derived signals are essential for the generation of germinal center B cells in response to T cell-dependent Ag. In fact, CD40LBTg mice generated a complex Ag-specific IgG1 response, which was greatly enhanced in early, but reduced in late, primary response compared with control mice. We also found that the frequency of Ag-specific germinal center B cells in CD40LBTg mice was abruptly reduced 1 wk after immunization. As a result, the numbers of Ag-specific IgG1 long-lived plasma cells and memory B cells were reduced. By histology, large numbers of Ag-specific plasma cells were found in T cell areas adjacent to Ag-specific germinal centers of CD40LBTg mice, temporarily during the second week of primary response. These results indicate that CD40L expression on B cells prematurely terminated their ongoing germinal center response and produced plasma cells. Our results support the notion that CD40 signaling is an active termination signal for germinal center reaction. PMID:20505142

Germinal Center T Follicular Helper Cell IL-4 Production Is Dependent on Signaling Lymphocytic Activation Molecule Receptor (CD150)

PubMed Central

Yusuf, Isharat; Kageyama, Robin; Monticelli, Laurel; Johnston, Robert J.; DiToro, Daniel; Hansen, Kyle; Barnett, Burton; Crotty, Shane

2010-01-01

CD4 T cell help is critical for the generation and maintenance of germinal centers (GCs), and T follicular helper (TFH) cells are the CD4 T cell subset required for this process. Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP [SH2D1A]) expression in CD4 T cells is essential for GC development. However, SAP-deficient mice have only a moderate defect in TFH differentiation, as defined by common TFH surface markers. CXCR5+ TFH cells are found within the GC, as well as along the boundary regions of T/B cell zones. In this study, we show that GC-associated T follicular helper (GC TFH) cells can be identified by their coexpression of CXCR5 and the GL7 epitope, allowing for phenotypic and functional analysis of TFH and GC TFH populations. GC TFH cells are a functionally discrete subset of further polarized TFH cells, with enhanced B cell help capacity and a specialized ability to produce IL-4 in a TH2-independent manner. Strikingly, SAP-deficient mice have an absence of the GC TFH cell subset and SAP− TFH cells are defective in IL-4 and IL-21 production. We further demonstrate that SLAM (Slamf1, CD150), a surface receptor that uses SAP signaling, is specifically required for IL-4 production by GC TFH cells. GC TFH cells require IL-4 and -21 production for optimal help to B cells. These data illustrate complexities of SAP-dependent SLAM family receptor signaling, revealing a prominent role for SLAM receptor ligation in IL-4 production by GC CD4 T cells but not in TFH cell and GC TFH cell differentiation. PMID:20525889

The hydroxyflavone, fisetin, suppresses mast cell activation induced by interaction with activated T cell membranes

PubMed Central

Nagai, K; Takahashi, Y; Mikami, I; Fukusima, T; Oike, H; Kobori, M

2009-01-01

Background and purpose: Cell-to-cell interactions between mast cells and activated T cells are increasingly recognized as a possible mechanism in the aetiology of allergic or non-allergic inflammatory disorders. To determine the anti-allergic effect of fisetin, we examined the ability of fisetin to suppress activation of the human mast cell line, HMC-1, induced by activated Jurkat T cell membranes. Experimental approach: HMC-1 cells were incubated with or without fisetin for 15 min and then co-cultured with Jurkat T cell membranes activated by phorbol-12-myristate 13-acetate for 16 h. We determined gene expression in activated HMC-1 cells by DNA microarray and quantitative reverse transcription (RT)-PCR analysis. We also examined activation of the transcription factor NF-κB and MAP kinases (MAPKs) in activated HMC-1 cells. Key results: Fisetin suppresses cell spreading and gene expression in HMC-1 cells stimulated by activated T cell membranes. Additionally, we show that these stimulated HMC-1 cells expressed granzyme B. The stimulatory interaction also induced activation of NF-κB and MAPKs; these activations were suppressed by fisetin. Fisetin also reduced the amount of cell surface antigen CD40 and intercellular adhesion molecule-1 (ICAM-1) on activated HMC-1 cells. Conclusions and implications: Fisetin suppressed activation of HMC-1 cells by activated T cell membranes by interfering with cell-to-cell interaction and inhibiting the activity of NF-κB and MAPKs and thereby suppressing gene expression. Fisetin may protect against the progression of inflammatory diseases by limiting interactions between mast cells and activated T cells. PMID:19702784

c-Myc-Induced Survivin Is Essential for Promoting the Notch-Dependent T Cell Differentiation from Hematopoietic Stem Cells

PubMed Central

Haque, Rizwanul; Song, Jianyong; Haque, Mohammad; Lei, Fengyang; Sandhu, Praneet; Ni, Bing; Zheng, Songguo; Fang, Deyu; Yang, Jin-Ming; Song, Jianxun

2017-01-01

Notch is indispensable for T cell lineage commitment, and is needed for thymocyte differentiation at early phases. During early stages of T cell development, active Notch prevents other lineage potentials including B cell lineage and myeloid cell (e.g., dendritic cell) lineage. Nevertheless, the precise intracellular signaling pathways by which Notch promotes T cell differentiation remain unclear. Here we report that the transcription factor c-Myc is a key mediator of the Notch signaling–regulated T cell differentiation. In a well-established in vitro differentiation model of T lymphocytes from hematopoietic stem cells, we showed that Notch1 and 4 directly promoted c-Myc expression; dominant-negative (DN) c-Myc inhibited early T cell differentiation. Moreover, the c-Myc expression activated by Notch signaling increased the expression of survivin, an inhibitor of apoptosis (IAP) protein. We further demonstrated that over-expression of c-Myc increased the abundance of survivin and the T cell differentiation thereof, whereas dn c-Myc reduced survivin levels and concomitantly retarded the differentiation. The c-Myc–dependent survivin induction is functionally germane, because Notch-dependent T cell differentiation was canceled by the depletion of survivin. These results identify both c-Myc and survivin as important mediators of the Notch signaling–regulated differentiation of T lymphocytes from hematopoietic stem cells. PMID:28272325

Engineered fusokine GIFT4 licenses the ability of B cells to trigger a tumoricidal T cell response

PubMed Central

Deng, Jiusheng; Yuan, Shala; Pennati, Andrea; Murphy, Jordan; Wu, Jian Hui; Lawson, David; Galipeau, Jacques

2014-01-01

Engineered chimeric cytokines can generate gain-of-function activity in immune cells. Here we report potent antitumor activity for a novel fusion cytokine generated by N-terminal coupling of GM-CSF to IL-4, generating a fusokine termed GIFT4. B cells treated with GIFT4 clustered GM-CSF and IL-4 receptors on the cell surface and displayed a pan-STAT hyperphosphorylation associated with acquisition of a distinct phenotype and function described to date. In C57BL/6J mice, administration of GIFT4 expanded endogenous B cells and suppressed the growth of B16F0 melanoma cells. Further, B16F0 melanoma cells engineered to secrete GIFT4 were rejected immunologically in a B cell-dependent manner. This effect was abolished when GIFT4-expressing B16F0 cells were implanted in B cell-deficient mice, confirming a B cell-dependent antitumor effect. Human GIFT4-licensed B cells primed cytotoxic T cells and specifically killed melanoma cells in vitro and in vivo. Taken together, our results demonstrated that GIFT4 could mediate expansion of B cells with potent antigen-specific effector function. GIFT4 may offer a novel immunotherapeutic tool and define a previously unrecognized potential for B cells in melanoma immunotherapy. PMID:24938765

CD4+CD25+ T-Cells Control Autoimmunity in the Absence of B-Cells

PubMed Central

Mariño, Eliana; Villanueva, Jeanette; Walters, Stacey; Liuwantara, David; Mackay, Fabienne; Grey, Shane T.

2009-01-01

OBJECTIVE Tumor necrosis factor ligand family members B-cell–activating factor (BAFF) and a proliferation-inducing ligand (APRIL) can exert powerful effects on B-cell activation and development, type 1 T-helper cell (Th1) immune responses, and autoimmunity. We examined the effect of blocking BAFF and APRIL on the development of autoimmune diabetes. RESEARCH DESIGN AND METHODS Female NOD mice were administered B-cell maturation antigen (BCMA)-Fc from 9 to 15 weeks of age. Diabetes incidence, islet pathology, and T- and B-cell populations were examined. RESULTS BCMA-Fc treatment reduced the severity of insulitis and prevented diabetes development in NOD mice. BCMA-Fc–treated mice showed reduced follicular, marginal-zone, and T2MZ B-cells. B-cell reduction was accompanied by decreased frequencies of pathogenic CD4+CD40+ T-cells and reduced Th1 cytokines IL-7, IL-15, and IL-17. Thus, T-cell activation was blunted with reduced B-cells. However, BCMA-Fc–treated mice still harbored detectable diabetogenic T-cells, suggesting that regulatory mechanisms contributed to diabetes prevention. Indeed, BCMA-Fc–treated mice accumulated increased CD4+CD25+ regulatory T-cells (Tregs) with age. CD4+CD25+ cells were essential for maintaining euglycemia because their depletion abrogated BCMA-Fc–mediated protection. BCMA-Fc did not directly affect Treg homeostasis given that CD4+CD25+Foxp3+ T-cells did not express TACI or BR3 receptors and that CD4+CD25+Foxp3+ T-cell frequencies were equivalent in wild-type, BAFF−/−, TACI−/−, BCMA−/−, and BR3−/− mice. Rather, B-cell depletion resulted in CD4+CD25+ T-cell–mediated protection from diabetes because anti-CD25 monoclonal antibody treatment precipitated diabetes in both diabetes-resistant NOD.μMT−/− and BCMA-Fc–treated mice. CONCLUSIONS BAFF/APRIL blockade prevents diabetes. BCMA-Fc reduces B-cells, subsequently blunting autoimmune activity and allowing endogenous regulatory mechanisms to preserve a

INTERFERON α ACTIVATES NF-κ B IN JAK1-DEFICIENT CELLS THROUGH A TYK2-DEPENDENT PATHWAY

PubMed Central

Yang, Chuan He; Murti, Aruna; Valentine, William J.; Du, Ziyun; Pfeffer, Lawrence M.

2005-01-01

In addition to activating members of the STAT transcription factor family, IFN α/β activates the NF-κ B transcription factor. To determine the role of the JAK-STAT pathway in NF-κ B activation by IFN, we examined NF-κ B activation in JAK1-deficient mutant human fibrosarcoma cells. In wild-type fibrosarcoma cells (2fTGH) IFN activates STAT1, STAT2 and STAT3, as well as NF-κB complexes comprised of p50 and p65. In contrast, in JAK1-deficient cells IFN induces NF-κB activation and NF-κB dependent gene transcription, but does not activate these STAT proteins and has no effect on STAT-dependent gene transcription. Expression of a catalytically-inactive TYK2 tyrosine kinase in JAK1-deficient cells, as well as in the highly IFN-sensitive Daudi lymphoblastoid cell line, abrogates NF-κB activation by IFN. Moreover, IFN does not promote NF-κB activation in TYK2-deficient mutant fibrosarcoma cells. Our results demonstrate a dichotomy between the classical JAK-STAT pathway and the NF-κB signaling pathway. In the IFN signaling pathway leading to STAT activation both JAK1 and TYK2 are essential, while NF-κB activation requires only TYK2. PMID:15883164

Tumor-specific CD4+ T cells develop cytotoxic activity and eliminate virus-induced tumor cells in the absence of regulatory T cells.

PubMed

Akhmetzyanova, Ilseyar; Zelinskyy, Gennadiy; Schimmer, Simone; Brandau, Sven; Altenhoff, Petra; Sparwasser, Tim; Dittmer, Ulf

2013-02-01

The important role of tumor-specific cytotoxic CD8(+) T cells is well defined in the immune control of the tumors, but the role of effector CD4(+) T cells is poorly understood. In the current research, we have used a murine retrovirus-induced tumor cell line of C57BL/6 mouse origin, namely FBL-3 cells, as a model to study basic mechanisms of immunological control and escape during tumor formation. This study shows that tumor-specific CD4(+) T cells are able to protect against virus-induced tumor cells. We show here that there is an expansion of tumor-specific CD4(+) T cells producing cytokines and cytotoxic molecule granzyme B (GzmB) in the early phase of tumor growth. Importantly, we demonstrate that in vivo depletion of regulatory T cells (Tregs) and CD8(+) T cells in FBL-3-bearing DEREG transgenic mice augments IL-2 and GzmB production by CD4(+) T cells and increases FV-specific CD4(+) T-cell effector and cytotoxic responses leading to the complete tumor regression. Therefore, the capacity to reject tumor acquired by tumor-reactive CD4(+) T cells largely depends on the direct suppressive activity of Tregs. We suggest that a cytotoxic CD4(+) T-cell immune response may be induced to enhance resistance against oncovirus-associated tumors.

Loss of T Cell and B Cell Quiescence Precedes the Onset of Microbial Flora-Dependent Wasting Disease and Intestinal Inflammation in Gimap5-Deficient Mice

PubMed Central

Barnes, Michael J.; Aksoylar, Halil; Krebs, Philippe; Bourdeau, Tristan; Arnold, Carrie N.; Xia, Yu; Khovananth, Kevin; Engel, Isaac; Sovath, Sosathya; Lampe, Kristin; Laws, Eleana; Saunders, Amy; Butcher, Geoffrey W.; Kronenberg, Mitchell; Steinbrecher, Kris; Hildeman, David; Grimes, H. Leighton; Beutler, Bruce; Hoebe, Kasper

2015-01-01

Homeostatic control of the immune system involves mechanisms that ensure the self-tolerance, survival and quiescence of hematopoietic-derived cells. In this study, we demonstrate that the GTPase of immunity associated protein (Gimap)5 regulates these processes in lymphocytes and hematopoietic progenitor cells. As a consequence of a recessive N-ethyl-N-nitrosourea–induced germline mutation in the P-loop of Gimap5, lymphopenia, hepatic extramedullary hematopoiesis, weight loss, and intestinal inflammation occur in homozygous mutant mice. Irradiated fetal liver chimeric mice reconstituted with Gimap5-deficient cells lose weight and become lymphopenic, demonstrating a hematopoietic cell-intrinsic function for Gimap5. Although Gimap5-deficient CD4+ T cells and B cells appear to undergo normal development, they fail to proliferate upon Ag-receptor stimulation although NF-κB, MAP kinase and Akt activation occur normally. In addition, in Gimap5-deficient mice, CD4+ T cells adopt a CD44high CD62Llow CD69low phenotype and show reduced IL-7rα expression, and T-dependent and T-independent B cell responses are abrogated. Thus, Gimap5-deficiency affects a noncanonical signaling pathway required for Ag-receptor–induced proliferation and lymphocyte quiescence. Antibiotic-treatment or the adoptive transfer of Rag-sufficient splenocytes ameliorates intestinal inflammation and weight loss, suggesting that immune responses triggered by microbial flora causes the morbidity in Gimap5-deficient mice. These data establish Gimap5 as a key regulator of hematopoietic integrity and lymphocyte homeostasis. PMID:20190135

Empty conformers of HLA-B preferentially bind CD8 and regulate CD8+ T cell function.

PubMed

Geng, Jie; Altman, John D; Krishnakumar, Sujatha; Raghavan, Malini

2018-05-09

When complexed with antigenic peptides, human leukocyte antigen (HLA) class I (HLA-I) molecules initiate CD8 + T cell responses via interaction with the T cell receptor (TCR) and co-receptor CD8. Peptides are generally critical for the stable cell surface expression of HLA-I molecules. However, for HLA-I alleles such as HLA-B*35:01, peptide-deficient (empty) heterodimers are thermostable and detectable on the cell surface. Additionally, peptide-deficient HLA-B*35:01 tetramers preferentially bind CD8 and to a majority of blood-derived CD8 + T cells via a CD8-dependent binding mode. Further functional studies reveal that peptide-deficient conformers of HLA-B*35:01 do not directly activate CD8 + T cells, but accumulate at the immunological synapse in antigen-induced responses, and enhance cognate peptide-induced cell adhesion and CD8 + T cell activation. Together, these findings indicate that HLA-I peptide occupancy influences CD8 binding affinity, and reveal a new set of regulators of CD8 + T cell activation, mediated by the binding of empty HLA-I to CD8. © 2018, Geng et al.

NF-kB activity-dependent P-selectin involved in ox-LDL-induced foam cell formation in U937 cell

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

Wang, Yi, E-mail: wangyi2004a@126.com; Wang, Xiang; Sun, Minghui

Highlights: {yields} Ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. {yields} Ox-LDL induced expression of P-selectin through degradation of IkBa and augment of NF-kB activity and protein level during macrophage-derived foam cell formation. {yields} P-selectin and NF-kB may be identified as pivotal regulators of ox-LDL-induced foam cell formation. {yields} Therapy based on the inhibition of P-selectin and NF-kB may complement conventional treatments to prevent atherosclerosis. -- Abstract: Oxidized low-density lipoprotein (ox-LDL) plays a critical role in regulation of atherosclerosis. However, little is known about the role of Nuclear factor kBmore » (NF-kB) activity-dependent P-selectin in ox-LDL-induced foam cell formation during atherosclerosis. In this study, we first investigated ox-LDL induced foam cell formation in the human U937 promonocytic cell line in a dose- and time-dependent manner. Treatment of U937 cells with ox-LDL increased lipid accumulation as well as intracellular cholesterol content. Next, a comparative analysis of gene expression profiling using cDNA microarray and Real-time-PCR indicated that ox-LDL exposure induced, in three treated groups, an extremely marked increase in the mRNA level of P-selectin. Protein levels of P-selectin and its upstream regulators IkBa and NF-kB showed that NF-kB pathway is involved in the ox-LDL-induced foam cell formation. Finally, overexpression of NF-kB significantly accelerated, whereas, inhibition of NF-kB with siRNA remarkably attenuated ox-LDL-induced macrophage-derived foam cell formation. It was concluded that the activity of NF-kB is augmented during macrophage-derived foam cell formation. Activation of NF-kB increased, whereas, inhibition of NF-kB decreased ox-LDL-induced P-selectin expression and lipid accumulation in macrophages, suggesting ox-LDL induced expression of P-selectin through degradation of IkBa and activation of NF-kB

delta opioid receptors stimulate Akt-dependent phosphorylation of c-jun in T cells.

PubMed

Shahabi, Nahid A; McAllen, Kathy; Sharp, Burt M

2006-02-01

Activation of naive T cells markedly up-regulates the expression of delta opioid receptors (DORs). These receptors are bound by DOR peptides released by T cells, modulating T cell functions such as interleukin-2 production, cellular proliferation, and chemotaxis. Previous studies have shown that DOR agonists [e.g., [D-Ala(2)-D-Leu(5)]-enkephalin (DADLE)] modulate T cell antigen receptor signaling through mitogen-activated protein kinases (MAPKs; i.e., extracellular signal-regulated kinases 1 and 2) and that DORs directly induce phosphorylation of activating transcription factor-2 (implicated in cytokine gene transcription) and its association with the MAPK c-jun1 NH(2)-terminal kinase (JNK). Such observations suggest that DORs may induce the phosphorylation of c-jun. These experiments were performed to test this hypothesis and determine the potential roles of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B). DADLE (10(-10) to 10(-6) M) dose-dependently induced c-jun phosphorylation. This was blocked by pertussis toxin and the DOR-specific antagonist naltindole. Fluorescence flow cytometry showed that DADLE significantly stimulated c-jun phosphorylation by T cells. DADLE stimulated phosphorylation of membrane-associated Akt; wortmannin and LY294002 ([2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one]), specific inhibitors of PI3K, abolished the DADLE-induced phosphorylation of c-jun. Finally, inhibitors of Akt and JNK blocked DADLE-induced phosphorylation of c-jun. Thus, activated DORs directly stimulate c-jun phosphorylation through a PI3K-dependent pathway in T cells, apparently involving Akt. This implies that DORs activate JNK through a novel pathway dependent on PI3K and Akt, thereby regulating the function of activator protein-1 transcription complexes containing c-jun and other transcription partners.

Suppression of unprimed T and B cells in antibody responses by irradiation-resistant and plastic-adherent suppressor cells in Toxoplasma gondii-infected mice

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

Suzuki, Y.; Kobayashi, A.

1983-04-01

In the acute phase of Toxoplasma infection, the function of both helper T and B cells was suppressed in primary antibody responses to dinitrophenol (DNP)-conjugated protein antigens. During the course of infection, the suppressive effect on T cells seems to continue longer than that on B cells, since suppression in responses to sheep erythrocytes, a T-dependent antigen, persisted longer than those to DNP-Ficoll, a T-independent antigen. Plastic-adherent cells from the spleens of Toxoplasma-infected and X-irradiated (400 rads) mice had strong suppressor activity in primary anti-sheep erythrocyte antibody responses of normal mouse spleen cells in vitro. These data suggest that themore » activation of irradiation-resistant and plastic-adherent suppressor cells causes the suppression of both T and B cells in Toxoplasma-infected mice.« less

Homeobox protein TLX3 activates miR-125b expression to promote T-cell acute lymphoblastic leukemia

PubMed Central

Renou, Laurent; Boelle, Pierre-Yves; Deswarte, Caroline; Spicuglia, Salvatore; Benyoucef, Aissa; Calvo, Julien; Uzan, Benjamin; Belhocine, Mohamed; Cieslak, Agata; Landman-Parker, Judith; Baruchel, Andre; Asnafi, Vahid; Pflumio, Françoise; Ballerini, Paola

2017-01-01

The oncogenic mechanisms driven by aberrantly expressed transcription factors in T-cell acute leukemia (T-ALL) are still elusive. MicroRNAs (miRNAs) play an important role in normal development and pathologies. Here, we examined the expression of 738 miRNA species in 41 newly diagnosed pediatric T-ALLs and in human thymus-derived cells. We found that expression of 2 clustered miRNAs, miR-125b/99a, peaks in primitive T cells and is upregulated in the T leukemia homeobox 3 (TLX3)–positive subtype of T-ALL. Using loss- and gain-of-function approaches, we established functional relationships between TLX3 and miR-125b. Both TLX3 and miR-125b support in vitro cell growth and in vivo invasiveness of T-ALL. Besides, ectopic expression of TLX3 or miR-125b in human hematopoietic progenitor cells enhances production of T-cell progenitors and favors their accumulation at immature stages of T-cell development resembling the differentiation arrest observed in TLX3 T-ALL. Ectopic miR-125b also remarkably accelerated leukemia in a xenograft model, suggesting that miR125b is an important mediator of the TLX3-mediated transformation program that takes place in immature T-cell progenitors. Mechanistically, TLX3-mediated activation of miR-125b may impact T-cell differentiation in part via repression of Ets1 and CBFβ genes, 2 regulators of T-lineage. Finally, we established that TLX3 directly regulates miR-125b production through binding and transactivation of LINC00478, a long noncoding RNA gene, which is the host of miR-99a/Let-7c/miR-125b. Altogether, our results reveal an original functional link between TLX3 and oncogenic miR-125b in T-ALL development. PMID:29296717

Engineered fusokine GIFT4 licenses the ability of B cells to trigger a tumoricidal T-cell response.

PubMed

Deng, Jiusheng; Yuan, Shala; Pennati, Andrea; Murphy, Jordan; Wu, Jian Hui; Lawson, David; Galipeau, Jacques

2014-08-01

Engineered chimeric cytokines can generate gain-of-function activity in immune cells. Here, we report potent antitumor activity for a novel fusion cytokine generated by N-terminal coupling of GM-CSF to IL4, generating a fusokine termed GIFT4. B cells treated with GIFT4 clustered GM-CSF and IL4 receptors on the cell surface and displayed a pan-STAT hyperphosphorylation associated with acquisition of a distinct phenotype and function described to date. In C57BL/6J mice, administration of GIFT4 expanded endogenous B cells and suppressed the growth of B16F0 melanoma cells. Furthermore, B16F0 melanoma cells engineered to secrete GIFT4 were rejected immunologically in a B-cell-dependent manner. This effect was abolished when GIFT4-expressing B16F0 cells were implanted in B-cell-deficient mice, confirming a B-cell-dependent antitumor effect. Human GIFT4-licensed B cells primed cytotoxic T cells and specifically killed melanoma cells in vitro and in vivo. Taken together, our results demonstrated that GIFT4 could mediate expansion of B cells with potent antigen-specific effector function. GIFT4 may offer a novel immunotherapeutic tool and define a previously unrecognized potential for B cells in melanoma immunotherapy. ©2014 American Association for Cancer Research.

Ability of γδ T cells to modulate the Foxp3 T cell response is dependent on adenosine.

PubMed

Liang, Dongchun; Woo, Jeong-Im; Shao, Hui; Born, Willi K; O'Brien, Rebecca L; Kaplan, Henry J; Sun, Deming

2018-01-01

Whether γδ T cells inhibit or enhance the Foxp3 T cell response depends upon their activation status. The critical enhancing effector in the supernatant is adenosine. Activated γδ T cells express adenosine receptors at high levels, which enables them to deprive Foxp3+ T cells of adenosine, and to inhibit their expansion. Meanwhile, cell-free supernatants of γδ T cell cultures enhance Foxp3 T cell expansion. Thus, inhibition and enhancement by γδ T cells of Foxp3 T cell response are a reflection of the balance between adenosine production and absorption by γδ T cells. Non-activated γδ T cells produce adenosine but bind little, and thus enhance the Foxp3 T cell response. Activated γδ T cells express high density of adenosine receptors and have a greatly increased ability to bind adenosine. Extracellular adenosine metabolism and expression of adenosine receptor A2ARs by γδ T cells played a major role in the outcome of γδ and Foxp3 T cell interactions. A better understanding of the functional conversion of γδ T cells could lead to γδ T cell-targeted immunotherapies for related diseases.

Bacterial Pathogens Induce Abscess Formation by CD4+ T-Cell Activation via the CD28–B7-2 Costimulatory Pathway

PubMed Central

Tzianabos, Arthur O.; Chandraker, Anil; Kalka-Moll, Wiltrud; Stingele, Francesca; Dong, Victor M.; Finberg, Robert W.; Peach, Robert; Sayegh, Mohamed H.

2000-01-01

Abscesses are a classic host response to infection by many pathogenic bacteria. The immunopathogenesis of this tissue response to infection has not been fully elucidated. Previous studies have suggested that T cells are involved in the pathologic process, but the role of these cells remains unclear. To delineate the mechanism by which T cells mediate abscess formation associated with intra-abdominal sepsis, the role of T-cell activation and the contribution of antigen-presenting cells via CD28-B7 costimulation were investigated. T cells activated in vitro by zwitterionic bacterial polysaccharides (Zps) known to induce abscess formation required CD28-B7 costimulation and, when adoptively transferred to the peritoneal cavity of naïve rats, promoted abscess formation. Blockade of T-cell activation via the CD28-B7 pathway in animals with CTLA4Ig prevented abscess formation following challenge with different bacterial pathogens, including Staphylococcus aureus, Bacteroides fragilis, and a combination of Enterococcus faecium and Bacteroides distasonis. In contrast, these animals had an increased abscess rate following in vivo T-cell activation via CD28 signaling. Abscess formation in vivo and T-cell activation in vitro required costimulation by B7-2 but not B7-1. These results demonstrate that abscess formation by pathogenic bacteria is under the control of a common effector mechanism that requires T-cell activation via the CD28–B7-2 pathway. PMID:11083777

Activation of human B cells by phosphorothioate oligodeoxynucleotides.

PubMed Central

Liang, H; Nishioka, Y; Reich, C F; Pisetsky, D S; Lipsky, P E

1996-01-01

To investigate the potential of DNA to elicit immune responses in man, we examined the capacity of a variety of oligodeoxynucleotides (ODNs) to stimulate highly purified T cell-depleted human peripheral blood B cells. Among 47 ODNs of various sequences tested, 12 phosphorothioate oligodeoxynucleotides (sODNs) induced marked B cell proliferation and Ig production. IL-2 augmented both proliferation and production of IgM, IgG, and IgA, as well as IgM anti-DNA antibodies, but was not necessary for B cell stimulation. Similarly, T cells enhanced stimulation, but were not necessary for B cell activation. After stimulation with the active sODNs, more than 95% of B cells expressed CD25 and CD86. In addition, B cells stimulated with sODNs expressed all six of the major immunoglobulin VH gene families. These results indicate that the human B cell response to sODN is polyclonal. Active sODN coupled to Sepharose beads stimulated B cells as effectively as the free sODN, suggesting that stimulation resulted from engagement of surface receptors. These data indicate that sODNs can directly induce polyclonal activation of human B cells in a T cell-independent manner by engaging as yet unknown B cell surface receptors. PMID:8787674

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

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

Gambhir, Lokesh; Checker, Rahul; Sharma, Deepak

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, CD71more » 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. - Highlights:: • Withaferin A (WA) inhibited T-cell and B-cell mediated immune responses. • WA increased basal ROS levels in lymphocytes. • WA directly interacted with GSH as studied using spectrophotometry and HPLC. • WA inhibited NF-κB nuclear translocation and binding of nuclear NF-κB to DNA. • WA inhibited induction of the graft-versus-host disease in mice.« less

Bacterially activated B-cells drive T cell differentiation towards Tr1 through PD-1/PD-L1 expression.

PubMed

Said, Sawsan Sudqi; Barut, Guliz Tuba; Mansur, Nesteren; Korkmaz, Asli; Sayi-Yazgan, Ayca

2018-04-01

Regulatory B cells (Bregs) play a crucial role in immunological tolerance primarily through the production of IL-10 in many diseases including autoimmune disorders, allergy, infectious diseases, and cancer. To date, various Breg subsets with overlapping phenotypes have been identified. However, the roles of Bregs in Helicobacter infection are largely unknown. In the present study, we investigate the phenotype and function of Helicobacter -stimulated B cells. Our results demonstrate that Helicobacter felis -stimulated IL-10- producing B cells (Hf stim - IL-10 + B) are composed of B10 and Transitional 2 Marginal Zone Precursor (T2-MZP) cells with expression of CD9, Tim-1, and programmed death 1 (PD-1). On the other hand, Helicobacter felis -stimulated IL-10- nonproducing B (Hf stim - IL-10 - B) cells are mainly marginal zone (MZ) B cells that express PD-L1 and secrete TGF-β, IL-6, and TNF-α, and IgM and IgG2b. Furthermore, we show that both Hf stim - IL-10 + B cells and Hf stim - IL-10 - B cells induce CD49b + LAG-3 + Tr1 cells. Here, we describe a novel mechanism for PD-1/PD-L1- driven B cell-dependent Tr1 cell differentiation. Finally, we explore the capability of Hf stim - IL-10 - B cells to induce Th17 cell differentiation, which we find to be dependent on TGF-β. Taken together, the current study demonstrates that Hf stim - B cells induce Tr1 cells through the PD-1/PD-L1 axis and Th17 cells by secreting TGF-β. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interleukin-4-dependent innate collaboration between iNKT cells and B-1 B cells controls adaptative contact sensitivity

PubMed Central

Campos, Regis A; Szczepanik, Marian; Itakura, Atsuko; Lisbonne, Mariette; Dey, Neelendu; Leite-de-Moraes, Maria C; Askenase, Philip W

2006-01-01

We showed that hepatic Vα14+ invariant natural killer T (iNKT) cells, via their rapid interleukin (IL)-4 production, activate B-1 cells to initiate contact sensitivity (CS). This innate collaboration was absent in IL-4–/– and signal transducer and activator of transcription (STAT)-6–/– mice and was inhibited by anti-IL-4 treatment. These mice have defective CS because they fail to locally recruit the sensitized effector T cells of acquired immunity. Their CS is reconstituted by transfer of downstream-acting 1-day immune B-1 cells from wild-type mice. Responses were not reconstituted with B-1 cells from IL-4 receptor-α–/– or STAT-6–/– mice, nor by IL-4 treatment of B cell-deficient mice at immunization. Finally, IL-4 was preferentially and transiently produced by hepatic iNKT cells within 7 min after sensitization to mediate collaboration between innate-like iNKT cells and the B-1 B cells that participate in the recruitment of effector T cells in vivo. PMID:16556268

Limited tumor infiltration by activated T effector cells restricts the therapeutic activity of regulatory T cell depletion against established melanoma

PubMed Central

Quezada, Sergio A.; Peggs, Karl S.; Simpson, Tyler R.; Shen, Yuelei; Littman, Dan R.; Allison, James P.

2008-01-01

Interference with inhibitory immunological checkpoints controlling T cell activation provides new opportunities to augment cancer immunotherapies. Whereas cytotoxic T lymphocyte–associated antigen-4 blockade has shown promising preclinical and clinical results, therapeutic CD4+CD25+ T reg cell depletion has failed to consistently enhance immune-based therapies. Using B16/BL6, a transplantable murine melanoma model, we show a dichotomy between the effects of T reg cell depletion on tumor rejection dependent on whether depletion occurs before (prophylactic) or after (therapeutic) tumor engraftment. Failure to promote rejection with therapeutic depletion is not related to lack of T reg cell depletion, to elimination of CD25+ effector T cells, or to a failure to enhance systemic antitumor T cell responses, but correlates with failure of effector cells to infiltrate the tumor and increase the intratumor ratio of effector T cell/T reg cell. Finally, systemic antitumor responses generated upon therapeutic T reg cell depletion are significantly stronger than those generated in the presence of T reg cells, and are capable of eliciting rejection of established tumors after transfer into immunoablated recipients receiving combination immunotherapy. The data demonstrate a dissociation between measurable systemic responses and tumor rejection during CD25-directed T reg cell depletion, and suggest an alternative, clinically applicable strategy for the treatment of established tumors. PMID:18725522

Bet v 1-specific T-cell receptor/forkhead box protein 3 transgenic T cells suppress Bet v 1-specific T-cell effector function in an activation-dependent manner.

PubMed

Schmetterer, Klaus G; Haiderer, Daniela; Leb-Reichl, Victoria M; Neunkirchner, Alina; Jahn-Schmid, Beatrice; Küng, Hans J; Schuch, Karina; Steinberger, Peter; Bohle, Barbara; Pickl, Winfried F

2011-01-01

Regulatory T (Treg) cells establish and maintain tolerance to self-antigens and many foreign antigens, such as allergens, by suppressing effector T-cell proliferation and function. We have previously shown that human T-cell receptor (TCR) αβ-chains specific for allergen-derived epitopes confer allergen specificity on peripheral blood T cells of individuals with and without allergy. To study the feasibility of generating allergen-specific human Treg cells by retroviral transduction of a transcription unit encoding forkhead box protein 3 (FOXP3) and allergen-specific TCR αβ-chains. cDNAs encoding the α and β-chains of a Bet v 1(142-153)-specific TCR (TCR alpha variable region 6/TCR beta variable region 20) and human FOXP3 were linked via picornaviral 2A sequences and expressed as single translational unit from an internal ribosomal entry site-green fluorescence protein-containing retroviral vector. Retrovirally transduced peripheral blood T cells were tested for expression of transgenes, Treg phenotype, and regulatory capacity toward allergen-specific effector T cells. Transduced T cells displayed a Treg phenotype with clear-cut upregulation of CD25, CD39, and cytotoxic T-lymphocyte antigen 4. The transduced cells were hyporesponsive in cytokine production and secretion and, like naturally occurring Treg cells, did not proliferate after antigen-specific or antigen-mimetic stimulation. However, proliferation was inducible upon exposure to exogenous IL-2. In coculture experiments, TRAV6(+)TRBV20(+)FOXP3(+) transgenic T cells, unlike FOXP3(+) single transgenic T cells or naturally occurring Treg cells, highly significantly suppressed T cell cytokine production and proliferation of corresponding allergen-specific effector T cells in an allergen-specific, dose-dependent manner. We demonstrate a transgenic approach to engineer human allergen-specific Treg cells that exert their regulatory function in an activation-dependent manner. Customized Treg cells might become

Aging Converts Innate B1a Cells into Potent CD8+ T Cell Inducers.

PubMed

Lee-Chang, Catalina; Bodogai, Monica; Moritoh, Kanako; Chen, Xin; Wersto, Robert; Sen, Ranjan; Young, Howard A; Croft, Michael; Ferrucci, Luigi; Biragyn, Arya

2016-04-15

B cell dysregulation in aging is thought to mostly occur in conventional B2 cells without affecting innate B1 cells. Elderly humans and mice also accumulate 4-1BBL(+)MHC class-I(Hi)CD86(Hi)B cells of unknown origin. In this article, we report that these cells, termed 4BL cells, are activated murine and possibly human B1a cells. The activation is mediated by aging human monocytes and murine peritoneal macrophages. They induce expression and activation of 4-1BBL and IFN-γR1 on B1a cells to subsequently upregulate membrane TNF-α and CD86. As a result, activated B1a/4BL cells induce expression of granzyme B in CD8(+)T cells by targeting TNFR2 via membrane TNF-α and providing costimulation with CD86. Thus, for the first time, to our knowledge, these results indicate that aging affects the function of B1a cells. Upon aging, these cells lose their tumor-supporting activity and become inducers of potentially antitumor and autoimmune CD8(+)T cells. Copyright © 2016 by The American Association of Immunologists, Inc.

DNA activates human immune cells through a CpG sequence-dependent manner

PubMed Central

Bauer, M; Heeg, K; Wagner, H; Lipford, G B

1999-01-01

While bacterial DNA and cytosine–guanosine-dinucleotide-containing oligonucleotides (CpG ODN) are well described activators of murine immune cells, their effect on human cells is inconclusive. We investigated their properties on human peripheral blood mononuclear cells (PBMC) and subsets thereof, such as purified monocytes, T and B cells. Here we demonstrate that bacterial DNA and CpG ODN induce proliferation of B cells, while other subpopulations, such as monocytes and T cells, did not proliferate. PBMC mixed cell cultures, as well as purified monocytes, produced interleukin-6 (IL-6), IL-12 and tumour necrosis factor-α upon stimulation with bacterial DNA; however, only IL-6 and IL-12 secretion became induced upon CpG ODN stimulation. We conclude that monocytes, but not B or T cells, represent the prime source of cytokines. Monocytes up-regulated expression of antigen-presenting, major histocompatibility complex class I and class II molecules in response to CpG DNA. In addition, both monocytes and B cells up-regulate costimulatory CD86 and CD40 molecules. The activation by CpG ODN depended on sequence motifs containing the core dinucleotide CG since destruction of the motif strongly reduced immunostimulatory potential. PMID:10457226

Intratumoral CpG-B promotes anti-tumoral neutrophil, cDC, and T cell cooperation without reprograming tolerogenic pDC.

PubMed

Humbert, Marion; Guery, Leslie; Brighouse, Dale; Lemeille, Sylvain; Hugues, Stephanie

2018-03-27

Cancer immunotherapies utilize distinct mechanisms to harness the power of the immune system to eradicate cancer cells. Therapeutic vaccines, aimed at inducing active immune responses against an existing cancer, are highly dependent on the immunological microenvironment, where many immune cell types display high levels of plasticity and, depending on the context, promote very different immunological outcomes. Among them, plasmacytoid dendritic cells (pDC), known to be highly immunogenic upon inflammation, are maintained in a tolerogenic state by the tumor microenvironment. Here we report that intratumoral (i.t.) injection of established solid tumors with CpG oligonucleotides-B (CpG-B) inhibits tumor growth. Interestingly, control of tumor growth was independent of tumor-associated (TA) pDC, which remained refractory to CpG-B stimulation and whose depletion did not alter the efficacy of the treatment. Instead, tumor growth inhibition subsequent to i.t. CpG-B injection depended on the recruitment of neutrophils into the milieu, resulting in the activation of conventional dendritic cells (cDC), subsequent increased anti-tumor T cell priming in draining lymph nodes, and enhanced effector T cell infiltration in the tumor microenvironment. These results reinforce the concept that intratumoral delivery of TLR9 agonists alters the tumor microenvironment by improving the anti-tumor activity of both innate and adaptive immune cells. Copyright ©2018, American Association for Cancer Research.

The lymphotoxin promoter is stimulated by HTLV-I tax activation of NF-kappa B in human T-cell lines.

PubMed

Paul, N L; Millet, I; Ruddle, N H

1993-07-01

The HTLV-I transcriptional activator tax was used to gain insight into the mechanism of lymphotoxin (LT; TNF-beta) gene induction. Tax-expressing cell lines produce LT biologic activity. An LT promoter (LT-293) CAT construct that contained an NF-kappa B site was active in the LT-producing C81-66-45 cell line, which contains defective HTLV-I but expresses tax. The observation that a mutated LT-kappa B construct (M1-CAT) was inactive in C81-66-45, confirmed the importance of NF-kappa B in LT gene expression. Tax was transfected into HTLV-I-negative human T-cell lines. Jurkat T cells stably expressing tax contained elevated levels of NF-kappa B that directly bound to the LT-kappa B site. Tax co-transfected with reporter constructs into Jurkat cells maximally activated HTLV-I-LTR-CAT and kappa B-fos-CAT and also activated LT-293 to a lesser extent. In JM T cells, tax induced LT-293 activity by two- to four-fold, though there was no induction of M1-CAT. The increase in LT-293 CAT activity mirrored the increase in LT biologic activity seen under these conditions. These studies, the first to demonstrate induction of LT promoter activity over basal levels, indicate that HTLV-I tax causes low-level activation of both endogenous LT and the LT promoter, at least in part through activation of NF-kappa B.

Tolerance without clonal expansion: self-antigen-expressing B cells program self-reactive T cells for future deletion.

PubMed

Frommer, Friederike; Heinen, Tobias J A J; Wunderlich, F Thomas; Yogev, Nir; Buch, Thorsten; Roers, Axel; Bettelli, Estelle; Müller, Werner; Anderton, Stephen M; Waisman, Ari

2008-10-15

B cells have been shown in various animal models to induce immunological tolerance leading to reduced immune responses and protection from autoimmunity. We show that interaction of B cells with naive T cells results in T cell triggering accompanied by the expression of negative costimulatory molecules such as PD-1, CTLA-4, B and T lymphocyte attenuator, and CD5. Following interaction with B cells, T cells were not induced to proliferate, in a process that was dependent on their expression of PD-1 and CTLA-4, but not CD5. In contrast, the T cells became sensitive to Ag-induced cell death. Our results demonstrate that B cells participate in the homeostasis of the immune system by ablation of conventional self-reactive T cells.

The Notch/Hes1 pathway sustains NF-κB activation through CYLD repression in T cell leukemia

PubMed Central

Espinosa, Lluis; Cathelin, Severine; D’Altri, Teresa; Trimarchi, Thomas; Statnikov, Alexander; Guiu, Jordi; Rodilla, Veronica; Inglés-Esteve, Julia; Nomdedeu, Josep; Bellosillo, Beatriz; Besses, Carles; Abdel-Wahab, Omar; Kucine, Nicole; Sun, Shao-Cong; Song, Guangchan; Mullighan, Charles C.; Levine, Ross L.; Rajewsky, Klaus; Aifantis, Iannis; Bigas, Anna

2010-01-01

SUMMARY It was previously shown that the NF-κB pathway is downstream of oncogenic Notch1 in T cell acute lymphoblastic leukemia (T-ALL). Here we visualize Notch-induced NF-κB activation using both human T-ALL cell lines and animal models. We demonstrate that Hes1, a canonical Notch target and transcriptional repressor, is responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by repressing the deubiquitinase CYLD, a negative IKK complex regulator. CYLD expression was found to be significantly suppressed in primary T-ALL. Finally, we demonstrate that IKK inhibition is a promising option for the targeted therapy of T-ALL as specific suppression of IKK expression and function affected both the survival of human T-ALL cells and the maintenance of the disease in vivo. PMID:20832754

The Notch/Hes1 pathway sustains NF-κB activation through CYLD repression in T cell leukemia.

PubMed

Espinosa, Lluis; Cathelin, Severine; D'Altri, Teresa; Trimarchi, Thomas; Statnikov, Alexander; Guiu, Jordi; Rodilla, Veronica; Inglés-Esteve, Julia; Nomdedeu, Josep; Bellosillo, Beatriz; Besses, Carles; Abdel-Wahab, Omar; Kucine, Nicole; Sun, Shao-Cong; Song, Guangchan; Mullighan, Charles C; Levine, Ross L; Rajewsky, Klaus; Aifantis, Iannis; Bigas, Anna

2010-09-14

It was previously shown that the NF-κB pathway is downstream of oncogenic Notch1 in T cell acute lymphoblastic leukemia (T-ALL). Here, we visualize Notch-induced NF-κB activation using both human T-ALL cell lines and animal models. We demonstrate that Hes1, a canonical Notch target and transcriptional repressor, is responsible for sustaining IKK activation in T-ALL. Hes1 exerts its effects by repressing the deubiquitinase CYLD, a negative IKK complex regulator. CYLD expression was found to be significantly suppressed in primary T-ALL. Finally, we demonstrate that IKK inhibition is a promising option for the targeted therapy of T-ALL as specific suppression of IKK expression and function affected both the survival of human T-ALL cells and the maintenance of the disease in vivo. Copyright © 2010 Elsevier Inc. All rights reserved.

Activation-Induced Killer Cell Immunoglobulin-like Receptor 3DL2 Binding to HLA-B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis.

PubMed

Ridley, Anna; Hatano, Hiroko; Wong-Baeza, Isabel; Shaw, Jacqueline; Matthews, Katherine K; Al-Mossawi, Hussein; Ladell, Kristin; Price, David A; Bowness, Paul; Kollnberger, Simon

2016-04-01

In the spondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin-like receptor 3DL2 (KIR-3DL2). The aim of this study was to determine the factors that induce KIR-3DL2 expression, and to characterize the relationship between HLA-B27 and the phenotype and function of KIR-3DL2-expressing CD4+ T cells in SpA. In total, 34 B27+ patients with SpA, 28 age- and sex-matched healthy controls (20 B27- and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template-switch anchored reverse transcription-polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme-linked immunosorbent assay. Cellular activation induced KIR-3DL2 expression on both naive and effector CD4+ T cells. KIR-3DL2 binding to B27+ cells promoted expression of KIR-3DL2, the Th17-specific transcription factor retinoic acid receptor-related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR-3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen-presenting cells, KIR-3DL2+CD4+ T cells produced less interleukin-2 (IL-2) but more IL-17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR-3DL2 to B27 heavy chains. KIR-3DL2 binding to HLA-B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA-B27-KIR-3DL2 interactions for the treatment of B27+ patients with SpA. © 2016 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of the American College of Rheumatology.

Non-T cell activation linker (NTAL) proteolytic cleavage as a terminator of activatory intracellular signals.

PubMed

Arbulo-Echevarria, Mikel M; Muñoz-Miranda, Juan Pedro; Caballero-García, Andrés; Poveda-Díaz, José L; Fernández-Ponce, Cecilia; Durán-Ruiz, M Carmen; Miazek, Arkadiusz; García-Cózar, Francisco; Aguado, Enrique

2016-08-01

Non-T cell activation linker is an adaptor protein that is tyrosine phosphorylated upon cross-linking of immune receptors expressed on B lymphocytes, NK cells, macrophages, basophils, or mast cells, allowing the recruitment of cytosolic mediators for downstream signaling pathways. Fas receptor acts mainly as a death receptor, and when cross-linked with Fas ligand, many proteins are proteolytically cleaved, including several signaling molecules in T and B cells. Fas receptor triggering also interferes with TCR intracellular signals, probably by means of proteolytic cleavage of several adaptor proteins. We have previously found that the adaptor linker for activation of T cells, evolutionarily related to non-T cell activation linker, is cleaved upon proapoptotic stimuli in T lymphocytes and thymocytes, in a tyrosine phosphorylation-dependent fashion. Here, we describe non-T cell activation linker proteolytic cleavage triggered in human B cells and monocytes by Fas cross-linking and staurosporine treatment. Non-T cell activation linker is cleaved, producing an N-terminal fragment of ∼22 kDa, and such cleavage is abrogated in the presence of caspase 8/granzyme B and caspase 3 inhibitors. Moreover, we have identified an aspartic acid residue at which non-T cell activation linker is cleaved, which similar to linker for activation of T cells, this aspartic acid residue is located close to tyrosine and serine residues, suggesting an interdependence of phosphorylation and proteolytic cleavage. Consistently, induction of non-T cell activation linker phosphorylation by pervanadate inhibits its cleavage. Interestingly, the truncated isoform of non-T cell activation linker, generated after cleavage, has a decreased signaling ability when compared with the full-length molecule. Altogether, our results suggest that cleavage of transmembrane adaptors constitutes a general mechanism for signal termination of immune receptors. © Society for Leukocyte Biology.

Aging Converts Innate B1a Cells into Potent CD8+ T Cell Inducers

PubMed Central

Lee-Chang, Catalina; Bodogai, Monica; Moritoh, Kanako; Chen, Xin; Wersto, Robert; Sen, Ranjan; Young, Howard A.; Croft, Michael; Ferrucci, Luigi; Biragyn, Arya

2016-01-01

B-cell dysregulation in aging is thought to mostly occur in conventional B2 cells without affecting innate B1 cells. Elderly humans and mice also accumulate 4-1BBL+ MHC class-IHi CD86Hi B cells of unknown origin. Here we report that these cells, termed 4BL cells, are activated murine and possibly human B1a cells. The activation is mediated by aging human monocytes and murine peritoneal macrophages. The 4BL cells induce expression of 4-1BBL and IFNγR1 on B1a cells resulting in subsequent up regulation of membrane TNFα (mTNFα) and CD86. As a result, B1a cells induce expression of granzyme B in CD8+T cells by targeting TNFR2 via mTNFα while providing co-stimulation with CD86. Thus, for the first time, these results indicate that aging affects the function of B1a cells. Upon aging, these cells lose their tumor-supporting activity and become inducers of potentially antitumor and autoimmune CD8+T cells. PMID:26983789

Activation of B Cells by a Dendritic Cell-Targeted Oral Vaccine

PubMed Central

Sahay, Bikash; Owen, Jennifer L.; Yang, Tao; Zadeh, Mojgan; Lightfoot, Yaíma L.; Ge, Jun-Wei; Mohamadzadeh, Mansour

2015-01-01

Production of long-lived, high affinity humoral immunity is an essential characteristic of successful vaccination and requires cognate interactions between T and B cells in germinal centers. Within germinal centers, specialized T follicular helper cells assist B cells and regulate the antibody response by mediating the differentiation of B cells into memory or plasma cells after exposure to T cell-dependent antigens. It is now appreciated that local immune responses are also essential for protection against infectious diseases that gain entry to the host by the mucosal route; therefore, targeting the mucosal compartments is the optimum strategy to induce protective immunity. However, because the gastrointestinal mucosae are exposed to large amounts of environmental and dietary antigens on a daily basis, immune regulatory mechanisms exist to favor tolerance and discourage autoimmunity at these sites. Thus, mucosal vaccination strategies must ensure that the immunogen is efficiently taken up by the antigen presenting cells, and that the vaccine is capable of activating humoral and cellular immunity, while avoiding the induction of tolerance. Despite significant progress in mucosal vaccination, this potent platform for immunotherapy and disease prevention must be further explored and refined. Here we discuss recent progress in the understanding of the role of different phenotypes of B cells in the development of an efficacious mucosal vaccine against infectious disease. PMID:24372255

Activated T cells sustain myeloid-derived suppressor cell-mediated immune suppression

PubMed Central

Damuzzo, Vera; Francescato, Samuela; Pozzuoli, Assunta; Berizzi, Antonio; Mocellin, Simone; Rossi, Carlo Riccardo; Bronte, Vincenzo; Mandruzzato, Susanna

2016-01-01

The expansion of myeloid derived suppressor cells (MDSCs), a suppressive population able to hamper the immune response against cancer, correlates with tumor progression and overall survival in several cancer types. We have previously shown that MDSCs can be induced in vitro from precursors present in the bone marrow and observed that these cells are able to actively proliferate in the presence of activated T cells, whose activation level is critical to drive the suppressive activity of MDSCs. Here we investigated at molecular level the mechanisms involved in the interplay between MDSCs and activated T cells. We found that activated T cells secrete IL-10 following interaction with MDSCs which, in turn, activates STAT3 phosphorylation on MDSCs then leading to B7-H1 expression. We also demonstrated that B7-H1+ MDSCs are responsible for immune suppression through a mechanism involving ARG-1 and IDO expression. Finally, we show that the expression of ligands B7-H1 and MHC class II both on in vitro-induced MDSCs and on MDSCs in the tumor microenvironment of cancer patients is paralleled by an increased expression of their respective receptors PD-1 and LAG-3 on T cells, two inhibitory molecules associated with T cell dysfunction. These findings highlight key molecules and interactions responsible for the extensive cross-talk between MDSCs and activated T cells that are at the basis of immune suppression. PMID:26700461

Novel Derivative of Benzofuran Induces Cell Death Mostly by G2/M Cell Cycle Arrest through p53-dependent Pathway but Partially by Inhibition of NF-κB*

PubMed Central

Manna, Sunil K.; Bose, Julie S.; Gangan, Vijay; Raviprakash, Nune; Navaneetha, Thota; Raghavendra, Pongali B.; Babajan, Banaganapalli; Kumar, Chitta S.; Jain, Swatantra K.

2010-01-01

The Dracaena resin is widely used in traditional medicine as an anticancer agent, and benzofuran lignan is the active component. In this report, we provide evidence that the synthetic derivative of benzofuran lignan (Benfur) showed antitumor activities. It induced apoptosis in p53-positive cells. Though it inhibited endotoxin-induced nuclear factor κB (NF-κB) activation in both p53-positive and -negative cells, the activation of caspase 3 was observed in p53-positive cells. It showed partial cell death effect in both p53-positive and -negative cells through inhibition of NF-κB. Cell cycle analysis using flow cytometry showed that treatment with this novel benozofuran lignan derivative to Jurkat T-cells, but not U-937 cells, resulted in a G2/M arrest in a dose- and time-dependent manner. It increased amounts of p21, p27, and cyclin B, but not phospho-Rb through p53 nuclear translocation in Jurkat T-cells, but not in U-937 cells. It inhibited amounts of MDM2 (murine double minute 2) by repressing the transcription factor Sp1, which was also proved in silico. It induced cell death in tumor cells, but not in primary T-cells. Overall, our data suggest that Benfur-mediated cell death is partially dependent upon NF-κB, but predominantly dependent on p53. Thus, this novel benzofuran lignan derivative can be effective chemopreventive or chemotherapeutic agent against malignant T-cells. PMID:20472557

Role of T-cell-specific nuclear factor κB in islet allograft rejection.

PubMed

Porras, Delia Lozano; Wang, Ying; Zhou, Ping; Molinero, Luciana L; Alegre, Maria-Luisa

2012-05-27

Pancreatic islet transplantation has the potential to cure type 1 diabetes, a chronic lifelong disease, but its clinical applicability is limited by allograft rejection. Nuclear factor κB (NF-κB) is a transcription factor important for survival and differentiation of T cells. In this study, we tested whether NF-κB in T cells is required for the rejection of islet allografts. Mice expressing a superrepressor form of NF-κB selectively in T cells (IκBαΔN-Tg mice) with or without the antiapoptotic factor Bcl-xL, or mice with impaired T-cell receptor (TCR)- and B cell receptor-driven NF-κB activity (CARMA1-KO mice) were rendered diabetic and transplanted with islet allografts. Secondary skin transplantation in long-term acceptors of islet allografts was used to test for the development of donor-specific tolerance. Immune infiltration of the transplanted islets was examined by immunofluorescence. TCR-transgenic CD4 T cells were used to follow T-cell priming and differentiation. Islet allograft survival was prolonged in IκBαΔN-Tg mice, although the animals did not develop donor-specific tolerance. Reduced NF-κB activity did not prevent T-cell priming or differentiation but reduced survival of activated T cells, as transgenic expression of Bcl-xL restored islet allograft rejection in IκBαΔN-Tg mice. Abolishing TCR- and B cell receptor-driven activation of NF-κB selectively by CARMA1 deficiency prevented T-cell priming and islet allograft rejection. Our data suggest that T cell-NF-κB plays an important role in the rejection of islet allografts. Targeting NF-κB selectively in lymphocytes seems a promising approach to facilitate acceptance of transplanted islets.

Doxycycline is an NF-κB inhibitor that induces apoptotic cell death in malignant T-cells

PubMed Central

Alexander-Savino, Carolina V.; Hayden, Matthew S.; Richardson, Christopher; Zhao, Jiyong; Poligone, Brian

2016-01-01

Cutaneous T-cell Lymphoma (CTCL) is a rare non-Hodgkin's lymphoma that can affect the skin, blood, and lymph nodes, and can metastasize at late stages. Novel therapies that target all affected disease compartments and provide longer lasting responses while being safe are needed. One potential therapeutic target is NF-λB, a regulator of immune responses and an important participant in carcinogenesis and cancer progression. As a transcription factor, NF-λB targets genes that promote cell proliferation and survival. Constitutive or aberrant activation of NF-λB is encountered in many types of cancer, including CTCL. Recently, while analyzing gene-expression profiles of a variety of small molecule compounds that target NF-λB, we discovered the tetracycline family of antibiotics, including doxycycline, to be potent inhibitors of the NF-λB pathway. Doxycycline is well-tolerated, safe, and inexpensive; and is commonly used as an antibiotic and anti-inflammatory for the treatment a multitude of medical conditions. In our current study, we show that doxycycline induces apoptosis in a dose dependent manner in multiple different cell lines from patients with the two most common subtypes of CTCL, Mycosis Fungoides (MF) and Sézary Syndrome (SS). Similar results were found using primary CD4+ T cells from a patient with SS. Doxycycline inhibits TNF induced NF-λB activation and reduces expression of NF-λB dependent anti-apoptotic proteins, such as BCL2α. Furthermore, we have identified that doxycycline induces apoptosis through reactive oxygen species. PMID:27732942

Doxycycline is an NF-κB inhibitor that induces apoptotic cell death in malignant T-cells.

PubMed

Alexander-Savino, Carolina V; Hayden, Matthew S; Richardson, Christopher; Zhao, Jiyong; Poligone, Brian

2016-11-15

Cutaneous T-cell Lymphoma (CTCL) is a rare non-Hodgkin's lymphoma that can affect the skin, blood, and lymph nodes, and can metastasize at late stages. Novel therapies that target all affected disease compartments and provide longer lasting responses while being safe are needed. One potential therapeutic target is NF-κB, a regulator of immune responses and an important participant in carcinogenesis and cancer progression. As a transcription factor, NF-κB targets genes that promote cell proliferation and survival. Constitutive or aberrant activation of NF-κB is encountered in many types of cancer, including CTCL.Recently, while analyzing gene-expression profiles of a variety of small molecule compounds that target NF-κB, we discovered the tetracycline family of antibiotics, including doxycycline, to be potent inhibitors of the NF-κB pathway. Doxycycline is well-tolerated, safe, and inexpensive; and is commonly used as an antibiotic and anti-inflammatory for the treatment a multitude of medical conditions.In our current study, we show that doxycycline induces apoptosis in a dose dependent manner in multiple different cell lines from patients with the two most common subtypes of CTCL, Mycosis Fungoides (MF) and Sézary Syndrome (SS). Similar results were found using primary CD4+ T cells from a patient with SS. Doxycycline inhibits TNF induced NF-κB activation and reduces expression of NF-κB dependent anti-apoptotic proteins, such as BCL2α. Furthermore, we have identified that doxycycline induces apoptosis through reactive oxygen species.

A pathway of costimulation that prevents anergy in CD28- T cells: B7- independent costimulation of CD1-restricted T cells

PubMed Central

1995-01-01

A class of molecules that is expressed on antigen presenting cells, exemplified by CD80 (B7), has been found to provide a necessary costimulatory signal for T cell activation and proliferation. CD28 and CTLA4 are the B7 counterreceptors and are expressed on the majority of human CD4+ T cells and many CD8+ T cells. The signal these molecules mediate is distinguished from other costimulatory signals by the finding that T cell recognition of antigen results in a prolonged state of T cell unresponsiveness or anergy, unless these costimulatory molecules are engaged. However, nearly half of the CD8+ and CD4-CD8- T cells lack CD28, and the costimulatory signals required for the activation of such cells are unknown. To understand the pathways of activation used by CD28- T cells, we have examined the costimulatory requirements of antigen-specific CD4-CD8- TCR(+)-alpha/beta circulating T cells that lack the expression of CD28. We have characterized two T cell lines, DN1 and DN6, that recognize a mycobacterial antigen, and are restricted not by major histocompatibility complex class I or II, but by CD1b or CD1c, two members of a family of major histocompatibility complex-related molecules that have been recently implicated in a distinct pathway for antigen presentation. Comparison of antigen-specific cytolytic responses of the DN1 and DN6 T cell lines against antigen-pulsed CD1+ monocytes or CD1+ B lymphoblastoid cell lines (B-LCL) demonstrated that these T cells recognized antigen presented by both types of cells. However, T cell proliferation occurred only when antigen was presented by CD1+ monocytes, indicating that the CD1+ monocytes expressed a costimulatory molecule that the B- LCL transfectants lacked. This hypothesis was confirmed by demonstrating that the T cells became anergic when incubated with the CD1(+)-transfected B-LCL in the presence of antigen, but not in the absence of antigen. The required costimulatory signal occurred by a CD28-independent mechanism since

Loss of Xist RNA from the inactive X during B cell development is restored in a dynamic YY1-dependent two-step process in activated B cells

PubMed Central

Syrett, Camille M.; Sindhava, Vishal; Hodawadekar, Suchita; Myles, Arpita; Liang, Guanxiang; Zhang, Yue; Nandi, Satabdi; Cancro, Michael; Atchison, Michael

2017-01-01

X-chromosome inactivation (XCI) in female lymphocytes is uniquely regulated, as the inactive X (Xi) chromosome lacks localized Xist RNA and heterochromatin modifications. Epigenetic profiling reveals that Xist RNA is lost from the Xi at the pro-B cell stage and that additional heterochromatic modifications are gradually lost during B cell development. Activation of mature B cells restores Xist RNA and heterochromatin to the Xi in a dynamic two-step process that differs in timing and pattern, depending on the method of B cell stimulation. Finally, we find that DNA binding domain of YY1 is necessary for XCI in activated B cells, as ex-vivo YY1 deletion results in loss of Xi heterochromatin marks and up-regulation of X-linked genes. Ectopic expression of the YY1 zinc finger domain is sufficient to restore Xist RNA localization during B cell activation. Together, our results indicate that Xist RNA localization is critical for maintaining XCI in female lymphocytes, and that chromatin changes on the Xi during B cell development and the dynamic nature of YY1-dependent XCI maintenance in mature B cells predisposes X-linked immunity genes to reactivation. PMID:28991910

Invariant NKT cells provide innate and adaptive help for B cells

PubMed Central

Vomhof-DeKrey, Emilie E.; Yates, Jennifer; Leadbetter, Elizabeth A.

2014-01-01

B cells rely on CD4+ T cells helper signals to optimize their responses to T-dependent antigens. Recently another subset of T cells has been identified which provides help for B cells, invariant natural killer T (iNKT) cells. INKT cells are unique because they provide both innate and adaptive forms of help to B cells, with divergent outcomes. iNKT cells are widely distributed throughout the spleen at rest, consolidate in the marginal zone of the spleen early after activation, and are later found in germinal centers. Understanding the activation requirements for iNKT cells has led to the development of glycolipid containing nanoparticles which efficiently activate iNKT cells, enhance their cooperation with B cells, and which hold promise for vaccine development. PMID:24514004

T cell-replacing factor for glucocorticosteroid-induced immunoglobulin production. A unique steroid-dependent cytokine

PubMed Central

1983-01-01

Glucocorticosteroids (GCS) added to otherwise unstimulated cultures of human peripheral blood mononuclear cells (PBMC) induce the synthesis and secretion of all classes of immunoglobulin. The magnitude of this response is similar to that seen with other polyclonal B cell activators such as pokeweed mitogen (PWM), and like that of PWM, the steroid effect is dependent on both T cells and monocytes. To determine the cellular target for GCS in these cultures, separated populations of T cells and non-T cells were preincubated with steroids and then recombined. No immunoglobulin was produced in any of these preincubation experiments. As a different approach to this question, supernatants were collected from various cell populations following stimulation with PWM, concanavalin A (Con A), phytohemagglutinin (PHA), alloantigens, or GCS. These supernatants were tested for their effects on GCS-induced Ig production by B cells. Supernatants from 3-d cultures of unstimulated, as well as GCS-treated, PBMC contained a T cell- replacing factor that permitted T-depleted PBMC to produce Ig upon steroid stimulation. This supernatant factor (TRF-S) could be produced in the absence of steroid stimulation, but both the factor and GCS were necessary for the induction of Ig synthesis. Production of the TRF-S required the presence of both T cells and adherent cells in culture and was found in the highest concentrations at 3-4 d of culture. Supernatants from cultures stimulated with PWM, PHA, Con A, and alloantigens did not contain detectable TRF-S activity, and TRF-S was unable to replace helper T cells for PWM-induced Ig production. TRF-S required the presence of adherent cells in the T cell-depleted responder population for its action. Further, it was effective in inducing Ig production along with GCS in the presence of a sufficient concentration of cyclosporin A to block all T cell helper activity for primary responses of PBMC to PWM or GCS. TRF-S was inactivated by trypsin treatment

A PKA survival pathway inhibited by DPT-PKI, a new specific cell permeable PKA inhibitor, is induced by T. annulata in parasitized B-lymphocytes.

PubMed

Guergnon, Julien; Dessauge, Frederic; Traincard, François; Cayla, Xavier; Rebollo, Angelita; Bost, Pierre Etienne; Langsley, Gordon; Garcia, Alphonse

2006-08-01

T. annulata, an intracellular pathogenic parasite of the Aplicomplexa protozoan family infects bovine B-lymphocytes and macrophages. Parasitized cells that become transformed survive and proliferate independently of exogenous growth factors. In the present study, we used the isogenic non parasitized BL3 and parasitized TBL3 B cell lines, as a model to evaluate the contribution of two-major PI3-K- and PKA-dependent anti-apoptotic pathways in the survival of T. annulata parasitized B lymphocytes. We found that T. annulata increases PKA activity, induces over-expression of the catalytic subunit and down-regulates the pro-survival phosphorylation state of Akt/PKB. Consistent with a role of PKA activation in survival, two pharmacological inhibitors H89 and KT5720 ablate PKA-dependent survival of parasitized cells. To specifically inhibit PKA pro-survival pathways we linked the DPTsh1 peptide shuttle sequence to PKI(5-24) and we generated DPT-PKI, a cell permeable PKI. DPT-PKI specifically inhibited PKA activity in bovine cell extracts and, as expected, also inhibited the PKA-dependent survival of T. annulata parasitized TBL3 cells. Thus, parasite-dependent constitutive activation of PKA in TBL3 cells generates an anti-apoptotic pathway that can protect T. annulata-infected B cells from apoptosis. These results also indicate that DPT-PKI could be a powerful tool to inhibit PKA pathways in other cell types.

Control of B-cell responses by Toll-like receptors

NASA Astrophysics Data System (ADS)

Pasare, Chandrashekhar; Medzhitov, Ruslan

2005-11-01

Toll-like receptors (TLRs) detect microbial infection and have an essential role in the induction of immune responses. TLRs can directly induce innate host defence responses, but the mechanisms of TLR-mediated control of adaptive immunity are not fully understood. Although TLR-induced dendritic cell maturation is required for activation of T-helper (TH) cells, the role of TLRs in B-cell activation and antibody production in vivo is not yet known. Here we show that activation and differentiation of TH cells is not sufficient for the induction of T-dependent B-cell responses. We find that, in addition to CD4+ T-cell help, generation of T-dependent antigen-specific antibody responses requires activation of TLRs in B cells.

ATP1B3 Protein Modulates the Restriction of HIV-1 Production and Nuclear Factor κ Light Chain Enhancer of Activated B Cells (NF-κB) Activation by BST-2*

PubMed Central

Nishitsuji, Hironori; Sugiyama, Ryuichi; Abe, Makoto; Takaku, Hiroshi

2016-01-01

Here, we identify ATP1B3 and fibrillin-1 as novel BST-2-binding proteins. ATP1B3 depletion in HeLa cells (BST-2-positive cells), but not 293T cells (BST-2-negative cells), induced the restriction of HIV-1 production in a BST-2-dependent manner. In contrast, fibrillin-1 knockdown reduced HIV-1 production in 293T and HeLa cells in a BST-2-independent manner. Moreover, NF-κB activation was enhanced by siATP1B3 treatment in HIV-1- and HIV-1ΔVpu-infected HeLa cells. In addition, ATP1B3 silencing induced high level BST-2 expression on the surface of HeLa cells. These results indicate that ATP1B3 is a co-factor that accelerates BST-2 degradation and reduces BST-2-mediated restriction of HIV-1 production and NF-κB activation. PMID:26694617

The pan-ErbB tyrosine kinase inhibitor canertinib induces caspase-mediated cell death in human T-cell leukemia (Jurkat) cells

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

Trinks, Cecilia, E-mail: Cecilia.trinks@liu.se; Severinsson, Emelie A., E-mail: Emelie.severinsson@liu.se; Holmlund, Birgitta, E-mail: Birgitta.holmlund@lio.se

2011-07-08

Highlights: {yields} Canertinib induces caspase-mediated apoptosis in T-cell leukemia cells in vitro. {yields} Canertinib mediates activation of the intrinsic apoptotic pathway. {yields} Canertinib induces apoptosis in an ErbB receptor independent manner. {yields} Lymphocyte specific proteins as well as survival kinases are inhibited. {yields} Canertinib may act as a multi-kinase inhibiting drug in human T-cell malignancies. -- Abstract: Canertinib is a novel ErbB-receptor inhibitor currently in clinical development for the treatment of solid tumors overexpressing ErbB-receptors. We have recently demonstrated that canertinib displays anti-proliferative and pro-apoptotic effects in human myeloid leukemia cells devoid of ErbB-receptors. The mechanism mediating these effects aremore » however unknown. In this study, we show that canertinib is able to act as a multi-kinase inhibitor by inhibition of several intracellular kinases involved in T-cell signaling such as Akt, Erk1/2 and Zap-70, and reduced Lck protein expression in the human T-cell leukemia cell line Jurkat. Treatment with canertinib at a concentration of 2 {mu}M caused accumulation of Jurkat cells in the G{sub 1} cell cycle phase and increased doses induced apoptosis in a time-dependent manner. Apoptotic signs of treated cells were detected by Annexin V staining and cleavage of PARP, caspase-3, -8, -9, -10 and Bid. A subset of the pro-apoptotic signals mediated by canertinib could be significantly reduced by specific caspase inhibitors. Taken together, these results demonstrate the dual ability of canertinib to downregulate important signaling pathways and to activate caspase-mediated intrinsic apoptosis pathway in human T-cell leukemia cells.« less

Gastrodin stimulates anticancer immune response and represses transplanted H22 hepatic ascitic tumor cell growth: Involvement of NF-κB signaling activation in CD4 + T cells

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

Shu, Guangwen; Yang, Tianming; Wang, Chaoyuan

2013-06-15

Gastrodia elata Blume (G. elata) is a famous restorative food in East Asia. It can be used as an auxiliary reagent in hepatocellular carcinoma (HCC) treatment. Previous studies unveiled that G. elata exhibited immunomodulatory activities. To explore the active ingredients contributing to its immunomodulatory activities, gastrodin, vanillin, and parishin B were purified from G. elata and their anti-HCC effects were assessed in vivo. Among these compounds, only gastrodin was capable of repressing transplanted H22 ascitic hepatic tumor cell growth in vivo with low toxicity. Further investigations were designed to explore the effects of gastrodin on the immune system of tumor-bearingmore » mice and potential molecular mechanisms underlying these effects. Our data showed that gastrodin ameliorated tumor cell transplantation-induced activation of endogenous pro-apoptotic pathway in CD4 + T cells and abnormalities in serum cytokine profiles in host animals. These events enhanced cytotoxic activities of natural killer and CD8 + T cells against H22 hepatic cancer cells. Gastrodin administration specifically upregulated mRNA levels of several nuclear factor κB (NF-κB) responsive genes in CD4 + T cells but not in CD8 + T cells. Chromatin immunoprecipitation assay showed that gastrodin increased the association of NF-κB p65 subunit to the promoter regions of IL-2 and Bcl-2 encoding genes in CD4 + T cells. Our investigations demonstrated that gastrodin is the main active ingredient contributing to the anticancer immunomodulatory properties of G. elata. Promoting NF-κB-mediated gene transcription in CD4 + T cells is implicated in its immunomodulatory activity. - Highlights: • Gastrodin stimulates anticancer immune response. • Gastrodin represses tumor transplantation-induced CD4 + T cell apoptosis. • Gastrodin activates NF-κB activity in CD4 + T cells.« less

CTLA4 Promotes Tyk2-STAT3-Dependent B-cell Oncogenicity.

PubMed

Herrmann, Andreas; Lahtz, Christoph; Nagao, Toshikage; Song, Joo Y; Chan, Wing C; Lee, Heehyoung; Yue, Chanyu; Look, Thomas; Mülfarth, Ronja; Li, Wenzhao; Jenkins, Kurt; Williams, John; Budde, Lihua E; Forman, Stephen; Kwak, Larry; Blankenstein, Thomas; Yu, Hua

2017-09-15

CTL-associated antigen 4 (CTLA4) is a well-established immune checkpoint for antitumor immune responses. The protumorigenic function of CTLA4 is believed to be limited to T-cell inhibition by countering the activity of the T-cell costimulating receptor CD28. However, as we demonstrate here, there are two additional roles for CTLA4 in cancer, including via CTLA4 overexpression in diverse B-cell lymphomas and in melanoma-associated B cells. CTLA4-CD86 ligation recruited and activated the JAK family member Tyk2, resulting in STAT3 activation and expression of genes critical for cancer immunosuppression and tumor growth and survival. CTLA4 activation resulted in lymphoma cell proliferation and tumor growth, whereas silencing or antibody-blockade of CTLA4 in B-cell lymphoma tumor cells in the absence of T cells inhibits tumor growth. This inhibition was accompanied by reduction of Tyk2/STAT3 activity, tumor cell proliferation, and induction of tumor cell apoptosis. The CTLA4-Tyk2-STAT3 signal pathway was also active in tumor-associated nonmalignant B cells in mouse models of melanoma and lymphoma. Overall, our results show how CTLA4-induced immune suppression occurs primarily via an intrinsic STAT3 pathway and that CTLA4 is critical for B-cell lymphoma proliferation and survival. Cancer Res; 77(18); 5118-28. ©2017 AACR . ©2017 American Association for Cancer Research.

MyD88-dependent expansion of an immature GR-1+CD11b+ population induces T cell suppression and Th2 polarization in sepsis

PubMed Central

Delano, Matthew J.; Scumpia, Philip O.; Weinstein, Jason S.; Coco, Dominique; Nagaraj, Srinivas; Kelly-Scumpia, Kindra M.; O'Malley, Kerri A.; Wynn, James L.; Antonenko, Svetlana; Al-Quran, Samer Z.; Swan, Ryan; Chung, Chun-Shiang; Atkinson, Mark A.; Ramphal, Reuben; Gabrilovich, Dmitry I.; Reeves, Wesley H.; Ayala, Alfred; Phillips, Joseph; LaFace, Drake; Heyworth, Paul G.; Clare-Salzler, Michael; Moldawer, Lyle L.

2007-01-01

Polymicrobial sepsis alters the adaptive immune response and induces T cell suppression and Th2 immune polarization. We identify a GR-1+CD11b+ population whose numbers dramatically increase and remain elevated in the spleen, lymph nodes, and bone marrow during polymicrobial sepsis. Phenotypically, these cells are heterogeneous, immature, predominantly myeloid progenitors that express interleukin 10 and several other cytokines and chemokines. Splenic GR-1+ cells effectively suppress antigen-specific CD8+ T cell interferon (IFN) γ production but only modestly suppress antigen-specific and nonspecific CD4+ T cell proliferation. GR-1+ cell depletion in vivo prevents both the sepsis-induced augmentation of Th2 cell–dependent and depression of Th1 cell–dependent antibody production. Signaling through MyD88, but not Toll-like receptor 4, TIR domain–containing adaptor-inducing IFN-β, or the IFN-α/β receptor, is required for complete GR-1+CD11b+ expansion. GR-1+CD11b+ cells contribute to sepsis-induced T cell suppression and preferential Th2 polarization. PMID:17548519

ONC201 selectively induces apoptosis in cutaneous T-cell lymphoma cells via activating pro-apoptotic integrated stress response and inactivating JAK/STAT and NF-κB pathways

PubMed Central

Ni, Xiao; Zhang, Xiang; Hu, Cheng-Hui; Langridge, Timothy; Tarapore, Rohinton S.; Allen, Joshua E.; Oster, Wolfgang; Duvic, Madeleine

2017-01-01

Cutaneous T-cell lymphomas (CTCLs) are extremely symptomatic and still incurable, and more effective and less toxic therapies are urgently needed. ONC201, an imipridone compound, has shown efficacy in pre-clinical studies in multiple advanced cancers. This study was to evaluate the anti-tumor activity of ONC201 on CTCL cells. The effect of ONC201 on the cell growth and apoptosis were evaluated in CTCL cell lines (n=8) and primary CD4+ malignant T cells isolated from CTCL patients (n=5). ONC201 showed a time-dependent cell growth inhibition in all treated cell lines with a concentration range of 1.25-10.0 μM. ONC201 also induced apoptosis in tested cells with a narrow concentration range of 2.5-10.0 μM, evidenced by increased Annexin V+ cells, accompanied by accumulated sub-G1 portions. ONC201 only induced apoptosis in CD4+ malignant T cells, not in normal CD4+ T cells. The activating transcription factor 4 (ATF4), a hallmark of integrated stress response, was upregulated in response to ONC201 whereas Akt was downregulated. In addition, molecules in JAK/STAT and NF-κB pathways, as well as IL-32β, were downregulated following ONC201 treatment. Thus, ONC201 exerts a potent and selective anti-tumor effect on CTCL cells. Its efficacy may involve activating integrated stress response through ATF4 and inactivating JAK/STAT and NF-κB pathways. PMID:28977902

ONC201 selectively induces apoptosis in cutaneous T-cell lymphoma cells via activating pro-apoptotic integrated stress response and inactivating JAK/STAT and NF-κB pathways.

PubMed

Ni, Xiao; Zhang, Xiang; Hu, Cheng-Hui; Langridge, Timothy; Tarapore, Rohinton S; Allen, Joshua E; Oster, Wolfgang; Duvic, Madeleine

2017-09-22

Cutaneous T-cell lymphomas (CTCLs) are extremely symptomatic and still incurable, and more effective and less toxic therapies are urgently needed. ONC201, an imipridone compound, has shown efficacy in pre-clinical studies in multiple advanced cancers. This study was to evaluate the anti-tumor activity of ONC201 on CTCL cells. The effect of ONC201 on the cell growth and apoptosis were evaluated in CTCL cell lines (n=8) and primary CD4 + malignant T cells isolated from CTCL patients (n=5). ONC201 showed a time-dependent cell growth inhibition in all treated cell lines with a concentration range of 1.25-10.0 μM. ONC201 also induced apoptosis in tested cells with a narrow concentration range of 2.5-10.0 μM, evidenced by increased Annexin V + cells, accompanied by accumulated sub-G1 portions. ONC201 only induced apoptosis in CD4 + malignant T cells, not in normal CD4 + T cells. The activating transcription factor 4 (ATF4), a hallmark of integrated stress response, was upregulated in response to ONC201 whereas Akt was downregulated. In addition, molecules in JAK/STAT and NF-κB pathways, as well as IL-32β, were downregulated following ONC201 treatment. Thus, ONC201 exerts a potent and selective anti-tumor effect on CTCL cells. Its efficacy may involve activating integrated stress response through ATF4 and inactivating JAK/STAT and NF-κB pathways.

Tumor cell-released TLR4 ligands stimulate Gr-1+CD11b+F4/80+ cells to induce apoptosis of activated T cells.

PubMed

Liu, Yan-Yan; Sun, Ling-Cong; Wei, Jing-Jing; Li, Dong; Yuan, Ye; Yan, Bin; Liang, Zhi-Hui; Zhu, Hui-Fen; Xu, Yong; Li, Bo; Song, Chuan-Wang; Liao, Sheng-Jun; Lei, Zhang; Zhang, Gui-Mei; Feng, Zuo-Hua

2010-09-01

Gr-1(+)CD11b(+)F4/80(+) cells play important roles in tumor development and have a negative effect on tumor immunotherapy. So far, the mechanisms underlying the regulation of their immunosuppressive phenotype by classical and alternative macrophage activation stimuli are not well elucidated. In this study, we found that molecules from necrotic tumor cells (NTC-Ms) stimulated Gr-1(+)CD11b(+)F4/80(+) cells to induce apoptosis of activated T cells but not nonstimulated T cells. The apoptosis-inducing capacity was determined by higher expression levels of arginase I and IL-10 relative to those of NO synthase 2 and IL-12 in Gr-1(+)CD11b(+)F4/80(+) cells, which were induced by NTC-Ms through TLR4 signaling. The apoptosis-inducing capacity of NTC-Ms-stimulated Gr-1(+)CD11b(+)F4/80(+) cells could be enhanced by IL-10. IFN-gamma may reduce the apoptosis-inducing capacity of Gr-1(+)CD11b(+)F4/80(+) cells only if their response to IFN-gamma was not attenuated. However, the potential of Gr-1(+)CD11b(+)F4/80(+) cells to express IL-12 in response to IFN-gamma could be attenuated by tumor, partially due to the existence of active STAT3 in Gr-1(+)CD11b(+)F4/80(+) cells and NTC-Ms from tumor. In this situation, IFN-gamma could not effectively reduce the apoptosis-inducing capacity of Gr-1(+)CD11b(+)F4/80(+) cells. Tumor immunotherapy with 4-1BBL/soluble programmed death-1 may significantly reduce, but not abolish the apoptosis-inducing capacity of Gr-1(+)CD11b(+)F4/80(+) cells in local microenvironment. Blockade of TLR4 signaling could further reduce the apoptosis-inducing capacity of Gr-1(+)CD11b(+)F4/80(+) cells and enhance the suppressive effect of 4-1BBL/soluble form of programmed death-1 on tumor growth. These findings indicate the relationship of distinct signaling pathways with apoptosis-inducing capacity of Gr-1(+)CD11b(+)F4/80(+) cells and emphasize the importance of blocking TLR4 signaling to prevent the induction of T cell apoptosis by Gr-1(+)CD11b(+)F4/80(+) cells.

Plasmacytoid dendritic cells induce NK cell-dependent, tumor antigen-specific T cell cross-priming and tumor regression in mice.

PubMed

Liu, Chengwen; Lou, Yanyan; Lizée, Gregory; Qin, Hong; Liu, Shujuan; Rabinovich, Brian; Kim, Grace J; Wang, Yi-Hong; Ye, Yang; Sikora, Andrew G; Overwijk, Willem W; Liu, Yong-Jun; Wang, Gang; Hwu, Patrick

2008-03-01

A prerequisite for strong adaptive antiviral immunity is the robust initial activation of the innate immune system, which is frequently mediated by TLR-activated plasmacytoid DCs (pDCs). Natural antitumor immunity is often comparatively weak, potentially due to the lack of TLR-mediated activation signals within the tumor microenvironment. To assess whether pDCs are capable of directly facilitating effective antitumor immune responses, mice bearing established subcutaneous B16 melanoma tumors were administered TLR9-activated pDCs directly into the tumor. We found that TLR9-activated pDCs induced robust, spontaneous CTL cross-priming against multiple B16 tumor antigens, leading to the regression of both treated tumors and untreated tumors at distant contralateral sites. This T cell cross-priming was mediated by conventional DCs (cDCs) and was completely dependent upon the early recruitment and activation of NK cells at the tumor site. NK cell recruitment was mediated by CCR5 via chemokines secreted by pDCs, and optimal IFN-gamma production by NK cells was mediated by OX40L expressed by pDCs. Our data thus demonstrated that activated pDCs are capable of initiating effective and systemic antitumor immunity through the orchestration of an immune cascade involving the sequential activation of NK cells, cDCs, and CD8(+) T cells.

Effects of overexpression of IL-1 receptor-associated kinase on NFkappaB activation, IL-2 production and stress-activated protein kinases in the murine T cell line EL4.

PubMed

Knop, J; Wesche, H; Lang, D; Martin, M U

1998-10-01

The association and activation of the IL-1 receptor-associated protein kinase (IRAK) to the IL-1 receptor complex is one of the earliest events detectable in IL-1 signal transduction. We generated permanent clones of the murine T cell line EL4 6.1 overexpressing human (h)IRAK to evaluate the role of this kinase in IL-1 signaling. Overexpression of hIRAK enhanced IL-1-stimulated activation of the transcription factor NFkappaB, whereas a truncated form (N-IRAK) specifically inhibited IL-1-dependent NFkappaB activity. In clones stably overexpressing hIRAK a weak constitutive activation of NFkappaB correlated with a low basal IL-2 production which was enhanced in an IL-1-dependent manner. Compared to the parental cell line the dose-response curve of IL-1-induced IL-2 production was shifted in both potency and efficacy. These results demonstrate that IRAK directly triggers NFkappaB-mediated gene expression in EL4 cells. Qualitatively different effects were observed for the IL-1-induced activation of stress-activated protein (SAP) kinases: permanent overexpression of IRAK did not affect the dose dependence but prolonged the kinetics of IL-1-induced activation of SAP kinases, suggesting that this signaling branch may be regulated by distinct mechanisms.

Ultraviolet B Radiation Stimulates the Interaction between Nuclear Factor of Activated T Cells 5 (NFAT5) and Nuclear Factor-Kappa B (NF-κB) in Human Lens Epithelial Cells.

PubMed

Chung, Inyoung; Hah, Young-Sool; Ju, SunMi; Kim, Ji-Hye; Yoo, Woong-Sun; Cho, Hee-Young; Yoo, Ji-Myong; Seo, Seong-Wook; Choi, Wan-Sung; Kim, Seong-Jae

2017-07-01

Nuclear factor-kappa B (NF-κB) has been proposed as a therapeutic target for the treatment of cataracts. The authors investigated the relationship between nuclear factor of activated T cells 5 (NFAT5) and NF-κB in ultraviolet B (UVB)-irradiated human lens epithelial (HLE) cells. Human lens epithelial B-3 (HLE-B3) cells were exposed to UVB light at a dose of 10 mJ/cm 2 and then incubated for 24 h. Cell viability was assessed by using the Cell Counting Kit-8 (CCK-8) assay. Gene expression level of NFAT5 was determined using real-time quantitative polymerase chain reaction (qPCR). Protein expression levels of NFAT5, NF-κB p65, and α-smooth muscle actin (α-SMA) and the association of NFAT5 with the NF-κB p65 subunit were measured by Western blot analysis and a co-immunoprecipitation assay, respectively. The cellular distribution of NFAT5 and NF-κB p65 was examined by triple immunofluorescence staining. At 24 h after UVB exposure, cell viability significantly decreased in a dose-dependent manner, and UVB light (15 and 20 mJ/cm 2 ) significantly increased the ROS generation. UVB irradiation increased NFAT5 mRNA and protein levels and increased phosphorylation of NF-κB in HLE-B3 cells. α-SMA protein levels were increased in the irradiated cells. In addition, NFAT5 and NF-κB translocated from the cytoplasm to the nucleus, and binding between the p65 subunit and NFAT5 was increased. Exposure to UVB radiation induces nuclear translocation and stimulates binding between NFAT5 and NF-κB proteins in HLE-B3 cells. These interactions may form part of the biochemical mechanism of cataractogenesis in UVB-irradiated HLECs.

CD22 Promotes B-1b Cell Responses to T Cell-Independent Type 2 Antigens.

PubMed

Haas, Karen M; Johnson, Kristen L; Phipps, James P; Do, Cardinal

2018-03-01

CD22 (Siglec-2) is a critical regulator of B cell activation and survival. CD22 -/- mice generate significantly impaired Ab responses to T cell-independent type 2 (TI-2) Ags, including haptenated Ficoll and pneumococcal polysaccharides, Ags that elicit poor T cell help and activate BCR signaling via multivalent epitope crosslinking. This has been proposed to be due to impaired marginal zone (MZ) B cell development/maintenance in CD22 -/- mice. However, mice expressing a mutant form of CD22 unable to bind sialic acid ligands generated normal TI-2 Ab responses, despite significantly reduced MZ B cells. Moreover, mice treated with CD22 ligand-binding blocking mAbs, which deplete MZ B cells, had little effect on TI-2 Ab responses. We therefore investigated the effects of CD22 deficiency on B-1b cells, an innate-like B cell population that plays a key role in TI-2 Ab responses. B-1b cells from CD22 -/- mice had impaired BCR-induced proliferation and significantly increased intracellular Ca 2+ concentration responses following BCR crosslinking. Ag-specific B-1b cell expansion and plasmablast differentiation following TI-2 Ag immunization was significantly impaired in CD22 -/- mice, consistent with reduced TI-2 Ab responses. We generated CD22 -/- mice with reduced CD19 levels (CD22 -/- CD19 +/- ) to test the hypothesis that augmented B-1b cell BCR signaling in CD22 -/- mice contributes to impaired TI-2 Ab responses. BCR-induced proliferation and intracellular Ca 2+ concentration responses were normalized in CD22 -/- CD19 +/- B-1b cells. Consistent with this, TI-2 Ag-specific B-1b cell expansion, plasmablast differentiation, survival, and Ab responses were rescued in CD22 -/- CD19 +/- mice. Thus, CD22 plays a critical role in regulating TI-2 Ab responses through regulating B-1b cell signaling thresholds. Copyright © 2018 by The American Association of Immunologists, Inc.

Using Antigen-Specific B Cells to Combine Antibody and T Cell-Based Cancer Immunotherapy.

PubMed

Wennhold, Kerstin; Thelen, Martin; Schlößer, Hans Anton; Haustein, Natalie; Reuter, Sabrina; Garcia-Marquez, Maria; Lechner, Axel; Kobold, Sebastian; Rataj, Felicitas; Utermöhlen, Olaf; Chakupurakal, Geothy; Theurich, Sebastian; Hallek, Michael; Abken, Hinrich; Shimabukuro-Vornhagen, Alexander; von Bergwelt-Baildon, Michael

2017-09-01

Cancer immunotherapy by therapeutic activation of T cells has demonstrated clinical potential. Approaches include checkpoint inhibitors and chimeric antigen receptor T cells. Here, we report the development of an alternative strategy for cellular immunotherapy that combines induction of a tumor-directed T-cell response and antibody secretion without the need for genetic engineering. CD40 ligand stimulation of murine tumor antigen-specific B cells, isolated by antigen-biotin tetramers, resulted in the development of an antigen-presenting phenotype and the induction of a tumor antigen-specific T-cell response. Differentiation of antigen-specific B cells into antibody-secreting plasma cells was achieved by stimulation with IL21, IL4, anti-CD40, and the specific antigen. Combined treatment of tumor-bearing mice with antigen-specific CD40-activated B cells and antigen-specific plasma cells induced a therapeutic antitumor immune response resulting in remission of established tumors. Human CEA or NY-ESO-1-specific B cells were detected in tumor-draining lymph nodes and were able to induce antigen-specific T-cell responses in vitro, indicating that this approach could be translated into clinical applications. Our results describe a technique for the exploitation of B-cell effector functions and provide the rationale for their use in combinatorial cancer immunotherapy. Cancer Immunol Res; 5(9); 730-43. ©2017 AACR . ©2017 American Association for Cancer Research.

Antigen-specific and nonspecific mediators of T cell/B cell cooperation. III. Characterization of the nonspecific mediator(s) from different sources.

PubMed

Harwell, L; Kappler, J W; Marrack, P

1976-05-01

T cell-containing lymphoid populations produce a nonantigen-specific mediator(s) (NSM) which can replace T cell helper function in vitro in the response of B cells to sheep red blood cells (SRBC), but not to the hapten-protein conjugate, trinitrophenyl-keyhole limpet hemocyanin, (TNP-KLH). NSM produced under three conditions: 1) stimulation of KLH-primed cells with KLH; 2) allogeneic stimulation of normal spleen cells; and 3) stimulation of normal spleen cells with Con A (but not PHA) are indistinguishable on the basis of their biologic activity and m.w., estimated as 30 to 40,000 daltons by G-200 chromatography. Production of NSM is dependent on the presence of T cells. The action of NSM on B cells responding to SRBC in the presence of 2-mercaptoethanol is unaffected by severe macrophage depletion. Extensive absorption of NSM with SRBC failed to remove its activity, confirming its nonantigen-specific nature.

Vav1 GEF activity is required for T cell mediated allograft rejection.

PubMed

Haubert, Dirk; Li, Jianping; Saveliev, Alexander; Calzascia, Thomas; Sutter, Esther; Metzler, Barbara; Kaiser, Daniel; Tybulewicz, Victor L J; Weckbecker, Gisbert

2012-06-01

The GDP exchange factor (GEF) Vav1 is a central signal transducer downstream of the T cell receptor and has been identified as a key factor for T cell activation in the context of allograft rejection. Vav1 has been shown to transduce signals both dependent and independent of its GEF function. The most promising approach to disrupt Vav1 activity by pharmacological inhibition would be to target its GEF function. However, the contribution of Vav1 GEF activity for allogeneic T cell activation has not been clarified yet. To address this question, we used knock-in mice bearing a mutated Vav1 with disrupted GEF activity but intact GEF-independent functions. T cells from these mice showed strongly reduced proliferation and activation in response to allogeneic stimulation. Furthermore, lack of Vav1 GEF activity strongly abrogated the in vivo expansion of T cells in a systemic graft-versus-host model. In a cardiac transplantation model, mice with disrupted Vav1 GEF activity show prolonged allograft survival. These findings demonstrate a strong requirement for Vav1 GEF activity for allogeneic T cell activation and graft rejection suggesting that disruption of Vav1 GEF activity alone is sufficient to induce significant immunosuppression. Copyright © 2012 Elsevier B.V. All rights reserved.

B cells and TCR avidity determine distinct functions of CD4+ T cells in retroviral infection1

PubMed Central

Ploquin, Mickaël J-Y; Eksmond, Urszula; Kassiotis, George

2011-01-01

The T-cell-dependent B-cell response relies on cognate interaction between B cells and CD4+ Th cells. However, the consequences of this interaction for CD4+ T cells are not entirely known. B cells generally promote CD4+ T-cell responses to pathogens, albeit to a variable degree. In contrast, CD4+ T-cell responses to self or tumor antigens are often suppressed by B cells. Here we demonstrated that interaction with B cells dramatically inhibited the function of virus-specific CD4+ T cells in retroviral infection. We have used Friend virus (FV) infection of mice as a model for retroviral infection, in which the behavior of virus-specific CD4+ T cells was monitored according to their TCR avidity. We report that avidity for antigen and interaction with B cells determine distinct aspects of the primary CD4+ T-cell response to FV infection. Virus-specific CD4+ T cells followed exclusive Th1 and T follicular helper (Tfh) differentiation. High avidity for antigen facilitated expansion during priming and enhanced the capacity for IFN-γ and IL-21 production. In contrast, Tfh differentiation was not affected by avidity for antigen. By reducing or preventing B-cell interaction we found that B cells promoted Tfh differentiation, induced programmed death 1 (PD-1) expression and inhibited IFN-γ production by virus-specific CD4+ T cells. Ultimately, B cells protected hosts from CD4+ T-cell-mediated immune pathology, at the detriment of CD4+ T-cell-mediated protective immunity. Our results suggest that B-cell presentation of vaccine antigens could be manipulated to direct the appropriate CD4+ T-cell response. PMID:21841129

Exposure of a distinct PDCA-1+ (CD317) B cell population to agonistic anti-4-1BB (CD137) inhibits T and B cell responses both in vitro and in vivo.

PubMed

Vinay, Dass S; Lee, Seung J; Kim, Chang H; Oh, Ho Sik; Kwon, Byoung S

2012-01-01

4-1BB (CD137) is an important T cell activating molecule. Here we report that it also promotes development of a distinct B cell subpopulation co-expressing PDCA-1. 4-1BB is expressed constitutively, and its expression is increased when PDCA-1(+) B cells are activated. We found that despite a high level of surface expression of 4-1BB on PDCA-1(+) B cells, treatment of these cells with agonistic anti-4-1BB mAb stimulated the expression of only a few activation markers (B7-2, MHC II, PD-L2), cytokines (IL-12p40/p70), and chemokines (MCP-1, RANTES), as well as sTNFR1, and the immunosuppressive enzyme, IDO. Although the PDCA-1(+) B cells stimulated by anti-4-1BB expressed MHC II at high levels and took up antigens efficiently, Ig class switching was inhibited when they were pulsed with T-independent (TI) or T-dependent (TD) Ags and adoptively transferred into syngeneic recipients. Furthermore, when anti-4-1BB-treated PDCA-1(+) B cells were pulsed with OVA peptide and combined with Vα2(+)CD4(+) T cells, Ag-specific cell division was inhibited both in vitro and in vivo. Our findings suggest that the 4-1BB signal transforms PDCA-1(+) B cells into propagators of negative immune regulation, and establish an important role for 4-1BB in PDCA-1(+) B cell development and function.

Force Dynamics During T Cell Activation

NASA Astrophysics Data System (ADS)

Garcia, David A.; Upadhyaya, Arpita

T cell activation is an essential step in the adaptive immune response. The binding of the T cell receptor (TCR) with antigen triggers signaling cascades and cell spreading. Physical forces exerted on the TCR by the cytoskeleton have been shown to induce signaling events. While cellular forces are known to depend on the mechanical properties of the cytoskeleton, the biophysical mechanisms underlying force induced activation of TCR-antigen interactions unknown. Here, we use traction force microscopy to measure the force dynamics of activated Jurkat T cells. The movements of beads embedded in an elastic gel serve as a non-invasive reporter of cytoskeletal and molecular motor dynamics. We examined the statistical structure of the force profiles throughout the cell during signaling activation. We found two spatially distinct active regimes of force generation characterized by different time scales. Typically, the interior of the cells was found to be more active than the periphery. Inhibition of myosin motor activity altered the correlation time of the bead displacements indicating additional sources of stochastic force generation. Our results indicate a complex interaction between myosin activity and actin polymerization dynamics in producing cellular forces in immune cells.

ErbB-targeted CAR T-cell immunotherapy of cancer.

PubMed

Whilding, Lynsey M; Maher, John

2015-01-01

Chimeric antigen receptor (CAR) based immunotherapy has been under development for the last 25 years and is now a promising new treatment modality in the field of cancer immunotherapy. The approach involves genetically engineering T cells to target malignant cells through expression of a bespoke fusion receptor that couples an HLA-independent antigen recognition domain to one or more intracellular T-cell activating modules. Multiple clinical trials are now underway in several centers to investigate CAR T-cell immunotherapy of diverse hematologic and solid tumor types. The most successful results have been achieved in the treatment of patients with B-cell malignancies, in whom several complete and durable responses have been achieved. This review focuses on the preclinical and clinical development of CAR T-cell immunotherapy of solid cancers, targeted against members of the ErbB family.

Role of the 2B4 Receptor in CD8+ T-Cell-Dependent Immune Control of Epstein-Barr Virus Infection in Mice With Reconstituted Human Immune System Components.

PubMed

Chijioke, Obinna; Marcenaro, Emanuela; Moretta, Alessandro; Capaul, Riccarda; Münz, Christian

2015-09-01

Patients with X-linked lymphoproliferative (XLP) disease due to deficiency in the adaptor molecule signaling lymphocytic activation molecule-associated protein (SAP) are highly susceptible to one specific viral pathogen, the Epstein-Barr virus (EBV). This susceptibility might result from impaired CD8(+) T-cell and natural killer cell responses to EBV infection in these patients. We demonstrate that antibody blocking of the SAP-dependent 2B4 receptor is sufficient to induce XLP-like aggravation of EBV disease in mice with reconstituted human immune system components. CD8(+) T cells require 2B4 for EBV-specific immune control, because 2B4 blockade after CD8(+) T-cell depletion did not further aggravate symptoms of EBV infection. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Antibody-Independent Control of γ-Herpesvirus Latency via B Cell Induction of Anti-Viral T Cell Responses

PubMed Central

McClellan, Kelly B; Gangappa, Shivaprakash; Speck, Samuel H; Virgin, Herbert W.

2006-01-01

B cells can use antibody-dependent mechanisms to control latent viral infections. It is unknown whether this represents the sole function of B cells during chronic viral infection. We report here that hen egg lysozyme (HEL)-specific B cells can contribute to the control of murine γ-herpesvirus 68 (γHV68) latency without producing anti-viral antibody. HEL-specific B cells normalized defects in T cell numbers and proliferation observed in B cell−/− mice during the early phase of γHV68 latency. HEL-specific B cells also reversed defects in CD8 and CD4 T cell cytokine production observed in B cell−/− mice, generating CD8 and CD4 T cells necessary for control of latency. Furthermore, HEL-specific B cells were able to present virally encoded antigen to CD8 T cells. Therefore, B cells have antibody independent functions, including antigen presentation, that are important for control of γ-herpesvirus latency. Exploitation of this property of B cells may allow enhanced vaccine responses to chronic virus infection. PMID:16789842

T-cell-dependent control of acute Giardia lamblia infections in mice.

PubMed

Singer, S M; Nash, T E

2000-01-01

We have studied immune mechanisms responsible for control of acute Giardia lamblia and Giardia muris infections in adult mice. Association of chronic G. lamblia infection with hypogammaglobulinemia and experimental infections of mice with G. muris have led to the hypothesis that antibodies are required to control these infections. We directly tested this hypothesis by infecting B-cell-deficient mice with either G. lamblia or G. muris. Both wild-type mice and B-cell-deficient mice eliminated the vast majority of parasites between 1 and 2 weeks postinfection with G. lamblia. G. muris was also eliminated in both wild-type and B-cell-deficient mice. In contrast, T-cell-deficient and scid mice failed to control G. lamblia infections, as has been shown previously for G. muris. Treatment of wild-type or B-cell-deficient mice with antibodies to CD4 also prevented elimination of G. lamblia, confirming a role for T cells in controlling infections. By infecting mice deficient in either alphabeta- or gammadelta-T-cell receptor (TCR)-expressing T cells, we show that the alphabeta-TCR-expressing T cells are required to control parasites but that the gammadelta-TCR-expressing T cells are not. Finally, infections in mice deficient in production of gamma interferon or interleukin 4 (IL-4) and mice deficient in responding to IL-4 and IL-13 revealed that neither the Th1 nor the Th2 subset is absolutely required for protection from G. lamblia. We conclude that a T-cell-dependent mechanism is essential for controlling acute Giardia infections and that this mechanism is independent of antibody and B cells.

Strong adhesion by regulatory T cells induces dendritic cell cytoskeletal polarization and contact-dependent lethargy.

PubMed

Chen, Jiahuan; Ganguly, Anutosh; Mucsi, Ashley D; Meng, Junchen; Yan, Jiacong; Detampel, Pascal; Munro, Fay; Zhang, Zongde; Wu, Mei; Hari, Aswin; Stenner, Melanie D; Zheng, Wencheng; Kubes, Paul; Xia, Tie; Amrein, Matthias W; Qi, Hai; Shi, Yan

2017-02-01

Dendritic cells are targeted by regulatory T (T reg) cells, in a manner that operates as an indirect mode of T cell suppression. In this study, using a combination of single-cell force spectroscopy and structured illumination microscopy, we analyze individual T reg cell-DC interaction events and show that T reg cells exhibit strong intrinsic adhesiveness to DCs. This increased DC adhesion reduces the ability of contacted DCs to engage other antigen-specific cells. We show that this unusually strong LFA-1-dependent adhesiveness of T reg cells is caused in part by their low calpain activities, which normally release integrin-cytoskeleton linkage, and thereby reduce adhesion. Super resolution imaging reveals that such T reg cell adhesion causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation, and skews Fascin-1-dependent actin polarization in DCs toward the T reg cell adhesion zone. Although it is reversible upon T reg cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. Our results reveal a dynamic cytoskeletal component underlying T reg cell-mediated DC suppression in a contact-dependent manner. © 2017 Chen et al.

B cells expressing the transcription factor T-bet drive lupus-like autoimmunity

PubMed Central

Rubtsov, Anatoly V.; Thurman, Joshua M.; Mennona, Johanna M.; Kappler, John W.; Marrack, Philippa

2017-01-01

B cells contribute to multiple aspects of autoimmune disorders and may play a role in triggering disease. Thus, targeting B cells may be a promising strategy for treating autoimmune disorders. Better understanding of the B cell subsets that are responsible for the development of autoimmunity will be critical for developing efficient therapies. Here we have reported that B cells expressing the transcription factor T-bet promote the rapid appearance of autoantibodies and germinal centers in spontaneous murine models of systemic lupus erythematosus (SLE). Conditional deletion of T-bet from B cells impaired the formation of germinal centers and mitigated the development of kidney damage and rapid mortality in SLE mice. B cell–specific deletion of T-bet was also associated with lower activation of both B cells and T cells. Taken together, our results suggest that targeting T-bet–expressing B cells may be a potential target for therapy for autoimmune diseases. PMID:28240602

Allelic Dependent Expression of an Activating Fc receptor on B cells Enhances Humoral Immune Responses

PubMed Central

Li, Xinrui; Wu, Jianming; Ptacek, Travis; Redden, David T; Brown, Elizabeth E; Alarcón, Graciela S; Ramsey-Goldman, Rosalind; Petri, Michelle A; Reveille, John D.; Kaslow, Richard A; Kimberly, Robert P; Edberg, Jeffrey C

2014-01-01

B cells are pivotal regulators of acquired immune responses and recent work in both experimental murine models and humans has demonstrated that subtle changes in the regulation of B cell function can significantly alter immunological responses. The balance of negative and positive signals in maintaining an appropriate B cell activation threshold is critical in B lymphocyte immune tolerance and autoreactivity. FcγRIIb (CD32B), the only recognized Fcγ receptor on B cells, provides IgG-mediated negative modulation through a tyrosine-based inhibition motif which down-regulates B cell receptor initiated signaling. These properties make FcγRIIb a promising target for antibody-based therapy. Here we report the discovery of allele-dependent expression of the activating FcγRIIc on B cells. Identical to FcγRIIb in the extracellular domain, FcγRIIc has a tyrosine-based activation motif in its cytoplasmic domain. In both human B cells and in B cells from mice transgenic for human FcγRIIc, FcγRIIc expression counterbalances the negative feedback of FcγRIIb and enhances humoral responses to immunization in mice and to BioThrax® vaccination in a human Anthrax vaccine trial. Moreover, the FCGR2C-ORF allele is associated with the risk of development of autoimmunity in humans. FcγRIIc expression on B cells challenges the prevailing paradigm of uni-directional negative feedback by IgG immune complexes via the inhibitory FcγRIIb, is a previously unrecognized determinant in human antibody/autoantibody responses, and opens the opportunity for more precise personalized use of B cell targeted antibody-based therapy. PMID:24353158

In vitro generation of helper T cells and suppressor T cells that regulate the cytolytic T lymphocyte response to trinitrophenyl-modified syngeneic cells.

PubMed

Gualde, N; Weinberger, O; Ratnofsky, S; Benacerraf, B; Burakoff, S J

1982-04-01

Helper T cells and suppressor T cells have been generated in vitro that regulate the cytolytic T lymphocyte (CTL) response to trinitrophenyl (TNP)-modified syngeneic cells. B6D2F1 helper cells generated to TNP-modified parental (P1) cells augment the CTL response to those P1-TNP-modified antigens but not to P2-TNP-modified antigens. The generation of these helper T cells requires the presence of splenic adherent cells and these helper T cells are radioresistant. A soluble factor can be obtained from the helper T cell cultures that can also augment the CTL response. The suppressor T cells generated in culture do not demonstrate the specificity observed with the helper T cells; however, they are antigen-dependent in their induction. Whether helper or suppressor activity is obtained depends upon the length of time cells are cultured in vitro.

In vitro generation of helper T cells and suppressor T cells that regulate the cytolytic T lymphocyte response to trinitrophenyl-modified syngeneic cells

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

Gualde, N.; Weinberger, O.; Ratnofsky, S.

1982-04-01

Helper T cells and suppressor T cells have been generated in vitro that regulate the cytolytic T lymphocyte (CTL) response to trinitrophenyl (TNP)-modified syngeneic cells. B6D2F1 helper cells generated to TNP-modified parental (P1) cells augment the CTL response to those P1-TNP-modified antigens but not to P2-TNP-modified antigens. The generation of these helper T cells requires the presence of splenic adherent cells and these helper T cells are radioresistant. A soluble factor can be obtained from the helper T cell cultures that can also augment the CTL response. The suppressor T cells generated in culture do not demonstrate the specificity observedmore » with the helper T cells; however, they are antigen-dependent in their induction. Whether helper or suppressor activity is obtained depends upon the length of time cells are cultured in vitro.« less

Raft-dependent endocytic movement and intracellular cluster formation during T cell activation triggered by concanavalin A.

PubMed

Yabuuchi, Satomi; Endo, Satoshi; Baek, KeangOk; Hoshino, Kunihide; Tsujino, Yoshio; Vestergaard, Mun'delanji C; Takagi, Masahiro

2017-12-01

Certain food ingredients can stimulate the human immune system. A lectin, concanavalin A (ConA), from Canavalia ensiformis (jack bean) is one of the most well-known food-derived immunostimulants and mediates activation of cell-mediated immunity through T cell proliferation. Generally, T cell activation is known to be triggered by the interaction between T cells and antigen-presenting cells (APCs) via a juxtacrine (contact-dependent) signaling pathway. The mechanism has been well characterized and is referred to as formation of the immunological synapse (IS). We were interested in the mechanism behind the T cell activation by food-derived ConA which might be different from that of T cell activation by APCs. The purpose of this study was to characterize T cell activation by ConA with regard to (i) movement of raft domain, (ii) endocytic vesicular transport, (iii) the cytoskeleton (actin and microtubules), and (iv) cholesterol composition. We found that raft-dependent endocytic movement was important for T cell activation by ConA and this movement was dependent on actin, microtubules, and cholesterol. The T cell signaling mechanism triggered by ConA can be defined as endocrine signaling which is distinct from the activation process triggered by interaction between T cells and APCs by juxtacrine signaling. Therefore, we hypothesized that T cell activation by ConA includes both two-dimensional superficial raft movement on the membrane surface along actin filaments and three-dimensional endocytic movement toward the inside of the cell along microtubules. These findings are important for developing new methods for immune stimulation and cancer therapy based on the function of ConA. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Strong adhesion by regulatory T cells induces dendritic cell cytoskeletal polarization and contact-dependent lethargy

PubMed Central

Mucsi, Ashley D.; Meng, Junchen; Yan, Jiacong; Zhang, Zongde; Wu, Mei; Hari, Aswin; Stenner, Melanie D.; Zheng, Wencheng; Kubes, Paul; Xia, Tie; Amrein, Matthias W.

2017-01-01

Dendritic cells are targeted by regulatory T (T reg) cells, in a manner that operates as an indirect mode of T cell suppression. In this study, using a combination of single-cell force spectroscopy and structured illumination microscopy, we analyze individual T reg cell–DC interaction events and show that T reg cells exhibit strong intrinsic adhesiveness to DCs. This increased DC adhesion reduces the ability of contacted DCs to engage other antigen-specific cells. We show that this unusually strong LFA-1–dependent adhesiveness of T reg cells is caused in part by their low calpain activities, which normally release integrin–cytoskeleton linkage, and thereby reduce adhesion. Super resolution imaging reveals that such T reg cell adhesion causes sequestration of Fascin-1, an actin-bundling protein essential for immunological synapse formation, and skews Fascin-1–dependent actin polarization in DCs toward the T reg cell adhesion zone. Although it is reversible upon T reg cell disengagement, this sequestration of essential cytoskeletal components causes a lethargic state of DCs, leading to reduced T cell priming. Our results reveal a dynamic cytoskeletal component underlying T reg cell–mediated DC suppression in a contact-dependent manner. PMID:28082358

Interleukin-7 induces HIV replication in primary naive T cells through a nuclear factor of activated T cell (NFAT)-dependent pathway

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

Managlia, Elizabeth Z.; Landay, Alan; Al-Harthi, Lena

2006-07-05

Interleukin (IL)-7 plays several roles critical to T cell maturation, survival, and homeostasis. Because of these functions, IL-7 is under investigation as an immune-modulator for therapeutic use in lymphopenic clinical conditions, including HIV. We reported that naive T cells, typically not permissive to HIV, can be productively infected when pre-treated with IL-7. We evaluated the mechanism by which IL-7-mediates this effect. IL-7 potently up-regulated the transcriptional factor NFAT, but had no effect on NF{kappa}B. Blocking NFAT activity using a number of reagents, such as Cyclosporin A, FK-506, or the NFAT-specific inhibitor known as VIVIT peptide, all markedly reduced IL-7-mediated inductionmore » of HIV replication in naive T cells. Additional neutralization of cytokines present in IL-7-treated cultures and/or those that have NFAT-binding sequences within their promotors indicated that IL-10, IL-4, and most significantly IFN{gamma}, all contribute to IL-7-induction of HIV productive replication in naive T cells. These data clarify the mechanism by which IL-7 can overcome the block to HIV productive infection in naive T cells, despite their quiescent cell status. These findings are relevant to the treatment of HIV disease and understanding HIV pathogenesis in the naive CD4+ T cell compartment, especially in light of the vigorous pursuit of IL-7 as an in vivo immune modulator.« less

Special regulatory T-cell review: T-cell dependent suppression revisited.

PubMed

Basten, Antony; Fazekas de St Groth, Barbara

2008-01-01

The concept of T-cell dependent regulation of immune responses has been a central tenet of immunological thinking since the delineation of the two cell system in the 1960s. Indeed T-cell dependent suppression was discovered before MHC restriction. When reviewing the data from the original wave of suppression, it is intriguing to reflect not just on the decline and fall of suppressor T cells in the 1980s, but on their equally dramatic return to respectability over the past decade. Hopefully their resurgence will be supported by solid mechanistic data that will underpin their central place in our current and future understanding of the immune system. Cannon to right of them, Cannon to left of them, Cannon in front of them Volley'd and thunder'd Storm'd at with shot and shell, Boldly they rode and well, Into the jaws of Death, Into the mouth of Hell, Rode the six hundred (suppressionists). (Adapted from The Charge of the Light Brigade, Alfred, Lord Tennyson)

The viral protein A238L inhibits cyclooxygenase-2 expression through a nuclear factor of activated T cell-dependent transactivation pathway.

PubMed

Granja, Aitor G; Nogal, Maria L; Hurtado, Carolina; Vila, Virginia; Carrascosa, Angel L; Salas, María L; Fresno, Manuel; Revilla, Yolanda

2004-12-17

Cyclooxygenase-2 is transiently induced upon cell activation or viral infections, resulting in inflammation and modulation of the immune response. Here we report that A238L, an African swine fever virus protein, efficiently inhibits cyclooxygenase-2 gene expression in Jurkat T cells and in virus-infected Vero cells. Transfection of Jurkat cells stably expressing A238L with cyclooxygenase-2 promoter-luciferase constructs containing 5'-terminal deletions or mutations in distal or proximal nuclear factor of activated T cell (NFAT) response elements revealed that these sequences are involved in the inhibition induced by A238L. Overexpression of a constitutively active version of the calcium-dependent phosphatase calcineurin or NFAT reversed the inhibition mediated by A238L on cyclooxygenase-2 promoter activation, whereas overexpression of p65 NFkappaB had no effect. A238L does not modify the nuclear localization of NFAT after phorbol 12-myristate 13-acetate/calcium ionophore stimulation. Moreover, we show that the mechanism by which the viral protein down-regulates cyclooxygenase-2 activity does not involve inhibition of the binding between NFAT and its specific DNA sequences into the cyclooxygenase-2 promoter. Strikingly, A238L dramatically inhibited the transactivation mediated by a GAL4-NFAT fusion protein containing the N-terminal transactivation domain of NFAT1. Taken together, these data indicate that A238L down-regulates cyclooxygenase-2 transcription through the NFAT response elements, being NFAT-dependent transactivation implicated in this down-regulation.

Endogenous antigen tunes the responsiveness of naive B cells but not T cells

PubMed Central

Zikherman, Julie; Parameswaran, Ramya; Weiss, Arthur

2012-01-01

In humans up to 75% of newly generated B cells and about 30% of mature B cells exhibit some degree of autoreactivity1. Yet, how B cells establish and maintain tolerance in the face of autoantigen exposure during and after development is not certain. Studies of model BCR transgenic systems have highlighted the critical role played by functional unresponsiveness or ‘anergy’2,3. Unlike T cells, evidence suggests that receptor editing and anergy, rather than deletion, account for much of B cell tolerance4,5. However, it remains unclear whether the mature diverse B cell repertoire of mice contains anergic autoreactive B cells, and if so, whether antigen was encountered during or after their development. By taking advantage of a reporter mouse in which B cell antigen receptor (BCR) signaling rapidly and robustly induces GFP expression under the control of the Nur77 regulatory region, antigen-dependent and – independent BCR signaling events in vivo during B cell maturation were visualized. Here we show that B cells encounter antigen during development in the spleen, and that this antigen exposure in turn tunes the responsiveness of BCR signaling in B cells at least partly by down-modulating expression of surface IgM but not IgD BCRs, and by modifying basal calcium levels. By contrast, no analogous process occurs in naive mature T cells. Our data demonstrate not only that autoreactive B cells persist in the mature repertoire, but that functional unresponsiveness or ‘anergy’ exists in the mature B cell repertoire along a continuum, a fact that has long been suspected, but never yet shown. These results have important implications for understanding how tolerance in T and B cells is differently imposed, and how these processes might go awry in disease. PMID:22902503

Stimulation of hair follicle stem cell proliferation through an IL-1 dependent activation of γδT-cells

PubMed Central

Dutta, Abhik; Pincha, Neha; Rana, Isha; Ghosh, Subhasri; Witherden, Deborah; Kandyba, Eve; MacLeod, Amanda; Kobielak, Krzysztof; Havran, Wendy L

2017-01-01

The cutaneous wound-healing program is a product of a complex interplay among diverse cell types within the skin. One fundamental process that is mediated by these reciprocal interactions is the mobilization of local stem cell pools to promote tissue regeneration and repair. Using the ablation of epidermal caspase-8 as a model of wound healing in Mus musculus, we analyzed the signaling components responsible for epithelial stem cell proliferation. We found that IL-1α and IL-7 secreted from keratinocytes work in tandem to expand the activated population of resident epidermal γδT-cells. A downstream effect of activated γδT-cells is the preferential proliferation of hair follicle stem cells. By contrast, IL-1α-dependent stimulation of dermal fibroblasts optimally stimulates epidermal stem cell proliferation. These findings provide new mechanistic insights into the regulation and function of epidermal cell–immune cell interactions and into how components that are classically associated with inflammation can differentially influence distinct stem cell niches within a tissue. PMID:29199946

Decreased Vδ2 γδ T cells associated with liver damage by regulation of Th17 response in patients with chronic hepatitis B.

PubMed

Wu, Xiaoli; Zhang, Ji-Yuan; Huang, Ang; Li, Yuan-Yuan; Zhang, Song; Wei, Jun; Xia, Siyuan; Wan, Yajuan; Chen, Weiwei; Zhang, Zheng; Li, Yangguang; Wen, Ti; Chen, Yan; Tanaka, Yoshimasa; Cao, Youjia; Wang, Puyue; Zhao, Liqing; Wu, Zhenzhou; Wang, Fu-Sheng; Yin, Zhinan

2013-10-15

 γδ T cells comprise a small subset of T cells and play a protective role against cancer and viral infections; however, their precise role in patients with chronic hepatitis B remains unclear.  Flow cytometry and immunofunctional assays were performed to analyze the impact of Vδ2 γδ (Vδ2) T cells in 64 immune-activated patients, 22 immune-tolerant carriers, and 30 healthy controls.  The frequencies of peripheral and hepatic Vδ2 T cells decreased with disease progression from immune tolerant to immune activated. In the latter group of patients, the decreases in peripheral and intrahepatic frequencies of Vδ2 T cells reversely correlated with alanine aminotransferase levels and histological activity index. These activated terminally differentiated memory phenotypic Vδ2 T cells exhibited impaired abilities in proliferation and chemotaxis, while maintained a relative intact interferon (IFN) γ production. Importantly, Vδ2 T cells, in vitro, significantly suppressed the production of cytokines associated with interleukin 17-producing CD4+ T (Th17) cells through both cell contact-dependent and IFN-γ-dependent mechanisms.  Inflammatory microenvironment in IA patients result in decreased numbers of Vδ2 T cells, which play a novel role by regulating the pathogenic Th17 response to protect the liver in patients with chronic hepatitis B.

Human immunodeficiency virus type 1 Nef protein inhibits NF-kappa B induction in human T cells.

PubMed Central

Niederman, T M; Garcia, J V; Hastings, W R; Luria, S; Ratner, L

1992-01-01

Human immunodeficiency virus type 1 (HIV-1) can establish a persistent and latent infection in CD4+ T lymphocytes (W. C. Greene, N. Engl. J. Med. 324:308-317, 1991; S. M. Schnittman, M. C. Psallidopoulos, H. C. Lane, L. Thompson, M. Baseler, F. Massari, C. H. Fox, N. P. Salzman, and A. S. Fauci, Science 245:305-308, 1989). Production of HIV-1 from latently infected cells requires host cell activation by T-cell mitogens (T. Folks, D. M. Powell, M. M. Lightfoote, S. Benn, M. A. Martin, and A. S. Fauci, Science 231:600-602, 1986; D. Zagury, J. Bernard, R. Leonard, R. Cheynier, M. Feldman, P. S. Sarin, and R. C. Gallo, Science 231:850-853, 1986). This activation is mediated by the host transcription factor NF-kappa B [G. Nabel and D. Baltimore, Nature (London) 326:711-717, 1987]. We report here that the HIV-1-encoded Nef protein inhibits the induction of NF-kappa B DNA-binding activity by T-cell mitogens. However, Nef does not affect the DNA-binding activity of other transcription factors implicated in HIV-1 regulation, including SP-1, USF, URS, and NF-AT. Additionally, Nef inhibits the induction of HIV-1- and interleukin 2-directed gene expression, and the effect on HIV-1 transcription depends on an intact NF-kappa B-binding site. These results indicate that defective recruitment of NF-kappa B may underlie Nef's negative transcriptional effects on the HIV-1 and interleukin 2 promoters. Further evidence suggests that Nef inhibits NF-kappa B induction by interfering with a signal derived from the T-cell receptor complex. Images PMID:1527859

Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells

PubMed Central

Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

2015-01-01

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells. PMID:25613934

Formalin-Inactivated Coxiella burnetii Phase I Vaccine-Induced Protection Depends on B Cells To Produce Protective IgM and IgG

PubMed Central

Peng, Ying; Schoenlaub, Laura; Elliott, Alexandra; Mitchell, William; Zhang, Yan

2013-01-01

To further understand the mechanisms of formalin-inactivated Coxiella burnetii phase I (PI) vaccine (PIV)-induced protection, we examined if B cell, T cell, CD4+ T cell, or CD8+ T cell deficiency in mice significantly affects the ability of PIV to confer protection against a C. burnetii infection. Interestingly, compared to wild-type (WT) mice, PIV conferred comparable levels of protection in CD4+ T cell- or CD8+ T cell-deficient mice and partial protection in T cell-deficient mice but did not provide measurable protection in B cell-deficient mice. These results suggest that PIV-induced protection depends on B cells. In addition, anti-PI-specific IgM was the major detectable antibody (Ab) in immune sera from PIV-vaccinated CD4+ T cell-deficient mice, and passive transfer of immune sera from PIV-vaccinated CD4+ T cell-deficient mice conferred significant protection. These results suggest that T cell-independent anti-PI-specific IgM may contribute to PIV-induced protection. Our results also suggested that PIV-induced protection may not depend on complement activation and Fc receptor-mediated effector functions. Furthermore, our results demonstrated that both IgM and IgG from PIV-vaccinated WT mouse sera were able to inhibit C. burnetii infection in vivo, but only IgM from PIV-vaccinated CD4+ T cell-deficient mouse sera inhibited C. burnetii infection. Collectively, these findings suggest that PIV-induced protection depends on B cells to produce protective IgM and IgG and that T cell-independent anti-PI-specific IgM may play a critical role in PIV-induced protection against C. burnetii infection. PMID:23545296

B7-H1 shapes T-cell-mediated brain endothelial cell dysfunction and regional encephalitogenicity in spontaneous CNS autoimmunity.

PubMed

Klotz, Luisa; Kuzmanov, Ivan; Hucke, Stephanie; Gross, Catharina C; Posevitz, Vilmos; Dreykluft, Angela; Schulte-Mecklenbeck, Andreas; Janoschka, Claudia; Lindner, Maren; Herold, Martin; Schwab, Nicholas; Ludwig-Portugall, Isis; Kurts, Christian; Meuth, Sven G; Kuhlmann, Tanja; Wiendl, Heinz

2016-10-11

Molecular mechanisms that determine lesion localization or phenotype variation in multiple sclerosis are mostly unidentified. Although transmigration of activated encephalitogenic T cells across the blood-brain barrier (BBB) is a crucial step in the disease pathogenesis of CNS autoimmunity, the consequences on brain endothelial barrier integrity upon interaction with such T cells and subsequent lesion formation and distribution are largely unknown. We made use of a transgenic spontaneous mouse model of CNS autoimmunity characterized by inflammatory demyelinating lesions confined to optic nerves and spinal cord (OSE mice). Genetic ablation of a single immune-regulatory molecule in this model [i.e., B7-homolog 1 (B7-H1, PD-L1)] not only significantly increased incidence of spontaneous CNS autoimmunity and aggravated disease course, especially in the later stages of disease, but also importantly resulted in encephalitogenic T-cell infiltration and lesion formation in normally unaffected brain regions, such as the cerebrum and cerebellum. Interestingly, B7-H1 ablation on myelin oligodendrocyte glycoprotein-specific CD4 + T cells, but not on antigen-presenting cells, amplified T-cell effector functions, such as IFN-γ and granzyme B production. Therefore, these T cells were rendered more capable of eliciting cell contact-dependent brain endothelial cell dysfunction and increased barrier permeability in an in vitro model of the BBB. Our findings suggest that a single immune-regulatory molecule on T cells can be ultimately responsible for localized BBB breakdown, and thus substantial changes in lesion topography in the context of CNS autoimmunity.

Deconvoluting Post-Transplant Immunity: Cell Subset-Specific Mapping Reveals Pathways for Activation and Expansion of Memory T, Monocytes and B Cells

PubMed Central

Grigoryev, Yevgeniy A.; Kurian, Sunil M.; Avnur, Zafi; Borie, Dominic; Deng, Jun; Campbell, Daniel; Sung, Joanna; Nikolcheva, Tania; Quinn, Anthony; Schulman, Howard; Peng, Stanford L.; Schaffer, Randolph; Fisher, Jonathan; Mondala, Tony; Head, Steven; Flechner, Stuart M.; Kantor, Aaron B.; Marsh, Christopher; Salomon, Daniel R.

2010-01-01

A major challenge for the field of transplantation is the lack of understanding of genomic and molecular drivers of early post-transplant immunity. The early immune response creates a complex milieu that determines the course of ensuing immune events and the ultimate outcome of the transplant. The objective of the current study was to mechanistically deconvolute the early immune response by purifying and profiling the constituent cell subsets of the peripheral blood. We employed genome-wide profiling of whole blood and purified CD4, CD8, B cells and monocytes in tandem with high-throughput laser-scanning cytometry in 10 kidney transplants sampled serially pre-transplant, 1, 2, 4, 8 and 12 weeks. Cytometry confirmed early cell subset depletion by antibody induction and immunosuppression. Multiple markers revealed the activation and proliferative expansion of CD45RO+CD62L− effector memory CD4/CD8 T cells as well as progressive activation of monocytes and B cells. Next, we mechanistically deconvoluted early post-transplant immunity by serial monitoring of whole blood using DNA microarrays. Parallel analysis of cell subset-specific gene expression revealed a unique spectrum of time-dependent changes and functional pathways. Gene expression profiling results were validated with 157 different probesets matching all 65 antigens detected by cytometry. Thus, serial blood cell monitoring reflects the profound changes in blood cell composition and immune activation early post-transplant. Each cell subset reveals distinct pathways and functional programs. These changes illuminate a complex, early phase of immunity and inflammation that includes activation and proliferative expansion of the memory effector and regulatory cells that may determine the phenotype and outcome of the kidney transplant. PMID:20976225

Deconvoluting post-transplant immunity: cell subset-specific mapping reveals pathways for activation and expansion of memory T, monocytes and B cells.

PubMed

Grigoryev, Yevgeniy A; Kurian, Sunil M; Avnur, Zafi; Borie, Dominic; Deng, Jun; Campbell, Daniel; Sung, Joanna; Nikolcheva, Tania; Quinn, Anthony; Schulman, Howard; Peng, Stanford L; Schaffer, Randolph; Fisher, Jonathan; Mondala, Tony; Head, Steven; Flechner, Stuart M; Kantor, Aaron B; Marsh, Christopher; Salomon, Daniel R

2010-10-14

A major challenge for the field of transplantation is the lack of understanding of genomic and molecular drivers of early post-transplant immunity. The early immune response creates a complex milieu that determines the course of ensuing immune events and the ultimate outcome of the transplant. The objective of the current study was to mechanistically deconvolute the early immune response by purifying and profiling the constituent cell subsets of the peripheral blood. We employed genome-wide profiling of whole blood and purified CD4, CD8, B cells and monocytes in tandem with high-throughput laser-scanning cytometry in 10 kidney transplants sampled serially pre-transplant, 1, 2, 4, 8 and 12 weeks. Cytometry confirmed early cell subset depletion by antibody induction and immunosuppression. Multiple markers revealed the activation and proliferative expansion of CD45RO(+)CD62L(-) effector memory CD4/CD8 T cells as well as progressive activation of monocytes and B cells. Next, we mechanistically deconvoluted early post-transplant immunity by serial monitoring of whole blood using DNA microarrays. Parallel analysis of cell subset-specific gene expression revealed a unique spectrum of time-dependent changes and functional pathways. Gene expression profiling results were validated with 157 different probesets matching all 65 antigens detected by cytometry. Thus, serial blood cell monitoring reflects the profound changes in blood cell composition and immune activation early post-transplant. Each cell subset reveals distinct pathways and functional programs. These changes illuminate a complex, early phase of immunity and inflammation that includes activation and proliferative expansion of the memory effector and regulatory cells that may determine the phenotype and outcome of the kidney transplant.

Arginine methylation catalyzed by PRMT1 is required for B cell activation and differentiation.

PubMed

Infantino, Simona; Light, Amanda; O'Donnell, Kristy; Bryant, Vanessa; Avery, Danielle T; Elliott, Michael; Tangye, Stuart G; Belz, Gabrielle; Mackay, Fabienne; Richard, Stephane; Tarlinton, David

2017-10-12

Arginine methylation catalyzed by protein arginine methyltransferases (PRMT) is a common post-translational modification in mammalian cells, regulating many important functions including cell signalling, proliferation and differentiation. Here we show the role of PRMT1 in B-cell activation and differentiation. PRMT1 expression and activity in human and mouse peripheral B cells increases in response to in vitro or in vivo activation. Deletion of the Prmt1 gene in mature B cells establishes that although the frequency and phenotype of peripheral B cell subsets seem unaffected, immune responses to T-cell-dependent and -independent antigens are substantially reduced. In vitro activation of Prmt1-deficient B cells with a variety of mitogens results in diminished proliferation, differentiation and survival, effects that are correlated with altered signal transduction from the B cell receptor. Thus PRMT1 activity in B cells is required for correct execution of multiple processes that in turn are necessary for humoral immunity.PRMT1 is an arginine methyltransferase involved in a variety of cell functions. Here the authors delete PRMT1 specifically in mature B cells to show the importance of arginine methylation for B cell proliferation, differentiation and survival, and thereby for humoral immunity.

T Follicular Helper Cells and B Cell Dysfunction in Aging and HIV-1 Infection

PubMed Central

Pallikkuth, Suresh; de Armas, Lesley; Rinaldi, Stefano; Pahwa, Savita

2017-01-01

T follicular helper (Tfh) cells are a subset of CD4 T cells that provide critical signals to antigen-primed B cells in germinal centers to undergo proliferation, isotype switching, and somatic hypermutation to generate long-lived plasma cells and memory B cells during an immune response. The quantity and quality of Tfh cells therefore must be tightly controlled to prevent immune dysfunction in the form of autoimmunity and, on the other hand, immune deficiency. Both Tfh and B cell perturbations appear during HIV infection resulting in impaired antibody responses to vaccines such as seasonal trivalent influenza vaccine, also seen in biologic aging. Although many of the HIV-associated defects improve with antiretroviral therapy (ART), excess immune activation and antigen-specific B and T cell responses including Tfh function are still impaired in virologically controlled HIV-infected persons on ART. Interestingly, HIV infected individuals experience increased risk of age-associated pathologies. This review will discuss Tfh and B cell dysfunction in HIV infection and highlight the impact of chronic HIV infection and aging on Tfh–B cell interactions. PMID:29109730

T Follicular Helper Cells and B Cell Dysfunction in Aging and HIV-1 Infection.

PubMed

Pallikkuth, Suresh; de Armas, Lesley; Rinaldi, Stefano; Pahwa, Savita

2017-01-01

T follicular helper (Tfh) cells are a subset of CD4 T cells that provide critical signals to antigen-primed B cells in germinal centers to undergo proliferation, isotype switching, and somatic hypermutation to generate long-lived plasma cells and memory B cells during an immune response. The quantity and quality of Tfh cells therefore must be tightly controlled to prevent immune dysfunction in the form of autoimmunity and, on the other hand, immune deficiency. Both Tfh and B cell perturbations appear during HIV infection resulting in impaired antibody responses to vaccines such as seasonal trivalent influenza vaccine, also seen in biologic aging. Although many of the HIV-associated defects improve with antiretroviral therapy (ART), excess immune activation and antigen-specific B and T cell responses including Tfh function are still impaired in virologically controlled HIV-infected persons on ART. Interestingly, HIV infected individuals experience increased risk of age-associated pathologies. This review will discuss Tfh and B cell dysfunction in HIV infection and highlight the impact of chronic HIV infection and aging on Tfh-B cell interactions.

B7-H1 limits the entry of effector CD8(+) T cells to the memory pool by upregulating Bim.

PubMed

Gibbons, Rachel M; Liu, Xin; Pulko, Vesna; Harrington, Susan M; Krco, Christopher J; Kwon, Eugene D; Dong, Haidong

2012-10-01

Protective T‑cell immunity against cancer and infections is dependent on the generation of a durable effector and memory T‑cell pool. Studies from cancer and chronic infections reveal that B7-H1 (PD-L1) engagement with its receptor PD-1 promotes apoptosis of effector T cells. It is not clear how B7-H1 regulates T‑cell apoptosis and the subsequent impact of B7-H1 on the generation of memory T cells. In immunized B7-H1-deficient mice, we detected an increased expansion of effector CD8(+) T cells and a delayed T‑cell contraction followed by the emergence of a protective CD8(+) T‑cell memory capable of completely rejecting tumor metastases in the lung. Intracellular staining revealed that antigen-primed CD8(+) T cells in B7-H1-deficient mice express lower levels of the pro-apoptotic molecule Bim. The engagement of activated CD8(+) T cells by a plate-bound B7-H1 fusion protein led to the upregulation of Bim and increased cell death. Assays based on blocking antibodies determined that both PD-1 and CD80 are involved in the B7-H1-mediated regulation of Bim in activated CD8(+) T cells. Our results suggest that B7-H1 may negatively regulate CD8(+) T‑cell memory by enhancing the depletion of effector CD8(+) T cells through the upregulation of Bim. Our findings may provide a new strategy for targeting B7-H1 signaling in effector CD8(+) T cells to achieve protective antitumor memory responses.

B cells and B cell products-helping to restore cellular immunity?

PubMed

Cascalho, Marilia; Platt, Jeffrey L

2006-01-01

T cells that provide vital protection against tumors, viruses and intracellular bacteria are thought to develop independently of B cells. However, recent discoveries suggest that development of T cells depends on B cells. One way B cells promote T cell development is by providing diverse peptides that may promote positive selection of thymocytes. Diverse peptides and B cells help in diversification of the T cell receptor repertoire and may decrease cross-reactivity in the mature T cell compartment. These new insights may provide the basis for the design of novel therapeutics.

The Major Histocompatibility Complex Class II Transactivator CIITA Inhibits the Persistent Activation of NF-κB by the Human T Cell Lymphotropic Virus Type 1 Tax-1 Oncoprotein

PubMed Central

Forlani, Greta; Abdallah, Rawan

2016-01-01

ABSTRACT Human T cell lymphotropic virus type 1 (HTLV-1) Tax-1, a key protein in HTLV-1-induced T cell transformation, deregulates diverse cell signaling pathways. Among them, the NF-κB pathway is constitutively activated by Tax-1, which binds to NF-κB proteins and activates the IκB kinase (IKK). Upon phosphorylation-dependent IκB degradation, NF-κB migrates into the nucleus, mediating Tax-1-stimulated gene expression. We show that the transcriptional regulator of major histocompatibility complex class II genes CIITA (class II transactivator), endogenously or ectopically expressed in different cells, inhibits the activation of the canonical NF-κB pathway by Tax-1 and map the region that mediates this effect. CIITA affects the subcellular localization of Tax-1, which is mostly retained in the cytoplasm, and this correlates with impaired migration of RelA into the nucleus. Cytoplasmic and nuclear mutant forms of CIITA reveal that CIITA exploits different strategies to suppress Tax-1-mediated NF-κB activation in both subcellular compartments. CIITA interacts with Tax-1 without preventing Tax-1 binding to both IKKγ and RelA. Nevertheless, CIITA affects Tax-1-induced IKK activity, causing retention of the inactive p50/RelA/IκB complex in the cytoplasm. Nuclear CIITA associates with Tax-1/RelA in nuclear bodies, blocking Tax-1-dependent activation of NF-κB-responsive genes. Thus, CIITA inhibits cytoplasmic and nuclear steps of Tax-1-mediated NF-κB activation. These results, together with our previous finding that CIITA acts as a restriction factor inhibiting Tax-1-promoted HTLV-1 gene expression and replication, indicate that CIITA is a versatile molecule that might also counteract Tax-1 transforming activity. Unveiling the molecular basis of CIITA-mediated inhibition of Tax-1 functions may be important in defining new strategies to control HTLV-1 spreading and oncogenic potential. IMPORTANCE HTLV-1 is the causative agent of human adult T cell leukemia

The Major Histocompatibility Complex Class II Transactivator CIITA Inhibits the Persistent Activation of NF-κB by the Human T Cell Lymphotropic Virus Type 1 Tax-1 Oncoprotein.

PubMed

Forlani, Greta; Abdallah, Rawan; Accolla, Roberto S; Tosi, Giovanna

2016-01-20

Human T cell lymphotropic virus type 1 (HTLV-1) Tax-1, a key protein in HTLV-1-induced T cell transformation, deregulates diverse cell signaling pathways. Among them, the NF-κB pathway is constitutively activated by Tax-1, which binds to NF-κB proteins and activates the IκB kinase (IKK). Upon phosphorylation-dependent IκB degradation, NF-κB migrates into the nucleus, mediating Tax-1-stimulated gene expression. We show that the transcriptional regulator of major histocompatibility complex class II genes CIITA (class II transactivator), endogenously or ectopically expressed in different cells, inhibits the activation of the canonical NF-κB pathway by Tax-1 and map the region that mediates this effect. CIITA affects the subcellular localization of Tax-1, which is mostly retained in the cytoplasm, and this correlates with impaired migration of RelA into the nucleus. Cytoplasmic and nuclear mutant forms of CIITA reveal that CIITA exploits different strategies to suppress Tax-1-mediated NF-κB activation in both subcellular compartments. CIITA interacts with Tax-1 without preventing Tax-1 binding to both IKKγ and RelA. Nevertheless, CIITA affects Tax-1-induced IKK activity, causing retention of the inactive p50/RelA/IκB complex in the cytoplasm. Nuclear CIITA associates with Tax-1/RelA in nuclear bodies, blocking Tax-1-dependent activation of NF-κB-responsive genes. Thus, CIITA inhibits cytoplasmic and nuclear steps of Tax-1-mediated NF-κB activation. These results, together with our previous finding that CIITA acts as a restriction factor inhibiting Tax-1-promoted HTLV-1 gene expression and replication, indicate that CIITA is a versatile molecule that might also counteract Tax-1 transforming activity. Unveiling the molecular basis of CIITA-mediated inhibition of Tax-1 functions may be important in defining new strategies to control HTLV-1 spreading and oncogenic potential. HTLV-1 is the causative agent of human adult T cell leukemia-lymphoma (ATLL). The viral

Roles of calpain-calpastatin system (CCS) in human T cell activation.

PubMed

Mikosik, Anna; Jasiulewicz, Aleksandra; Daca, Agnieszka; Henc, Izabella; Frąckowiak, Joanna E; Ruckemann-Dziurdzińska, Katarzyna; Foerster, Jerzy; Le Page, Aurelie; Bryl, Ewa; Fulop, Tamas; Witkowski, Jacek M

2016-11-22

The immune response is determined by the speed of the T cell reaction to antigens assured by a state of readiness for proliferation and cytokine secretion. Proliferation, apoptosis and motion of many cell types are controlled by cytoplasmic proteases - µ- and m-calpain - and their inhibitor calpastatin, together forming the "calpain-calpastatin system" (CCS), assumed to modify their targets only upon activation-dependent cytoplasmic Ca2+ increase. Contrastingly to this notion, using quantitative real time PCR and semiquantitative flow cytometry respectively, we show here that the CCS genes are constitutively expressed, and that both calpains are constitutively active in resting, circulating human CD4+ and CD8+ lymphocytes. Furthermore, we demonstrate that calpain inhibition in the resting T cells prevents them from proliferation in vitro and greatly reduces secretion of multiple cytokines. The mechanistic reason for these effects of calpain inhibition on T cell functions might be the demonstrated significant reduction of the expression of active (phosphorylated) upstream signalling molecules, including the phospholipase C gamma, p56Lck and NFκB, in the inhibitor-treated cells. Thus, we propose that the constitutive, self-regulatory calpain-calpastatin system activity in resting human T cells is a necessary, controlling element of their readiness for complex and effective response to antigenic challenge.

Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells.

PubMed

Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

2015-04-01

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

Curcumin Regulates Low-Linear Energy Transfer {gamma}-Radiation-Induced NF{kappa}B-Dependent Telomerase Activity in Human Neuroblastoma Cells

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

Aravindan, Natarajan, E-mail: naravind@ouhsc.ed; Veeraraghavan, Jamunarani; Madhusoodhanan, Rakhesh

2011-03-15

Purpose: We recently reported that curcumin attenuates ionizing radiation (IR)-induced survival signaling and proliferation in human neuroblastoma cells. Also, in the endothelial system, we have demonstrated that NF{kappa}B regulates IR-induced telomerase activity (TA). Accordingly, we investigated the effect of curcumin in inhibiting IR-induced NF{kappa}B-dependent hTERT transcription, TA, and cell survival in neuroblastoma cells. Methods and Materials: SK-N-MC or SH-SY5Y cells exposed to IR and treated with curcumin (10-100 nM) with or without IR were harvested after 1 h through 24 h. NF{kappa}B-dependent regulation was investigated either by luciferase reporter assays using pNF{kappa}B-, pGL3-354-, pGL3-347-, or pUSE-I{kappa}B{alpha}-Luc, p50/p65, or RelA siRNA-transfectedmore » cells. NF{kappa}B activity was analyzed using an electrophoretic mobility shift assay and hTERT expression using the quantitative polymerase chain reaction. TA was determined using the telomerase repeat amplification protocol assay and cell survival using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertrazolium bromide and clonogenic assay. Results: Curcumin profoundly inhibited IR-induced NF{kappa}B. Consequently, curcumin significantly inhibited IR-induced TA and hTERT mRNA at all points investigated. Furthermore, IR-induced TA is regulated at the transcriptional level by triggering telomerase reverse transcriptase (TERT) promoter activation. Moreover, NF{kappa}B becomes functionally activated after IR and mediates TA upregulation by binding to the {kappa}B-binding region in the promoter region of the TERT gene. Consistently, elimination of the NF{kappa}B-recognition site on the telomerase promoter or inhibition of NF{kappa}B by the I{kappa}B{alpha} mutant compromises IR-induced telomerase promoter activation. Significantly, curcumin inhibited IR-induced TERT transcription. Consequently, curcumin inhibited hTERT mRNA and TA in NF{kappa}B overexpressed cells. Furthermore, curcumin

Src-like adaptor protein (SLAP) regulates B cell receptor levels in a c-Cbl-dependent manner.

PubMed

Dragone, Leonard L; Myers, Margaret D; White, Carmen; Gadwal, Shyam; Sosinowski, Tomasz; Gu, Hua; Weiss, Arthur

2006-11-28

Src-like adaptor protein (SLAP) and c-Cbl recently have been shown to cooperate in regulating T cell receptor (TCR) levels in developing T cells. SLAP also is expressed in developing B cells, and its deficiency leads to alterations in B cell receptor (BCR) levels and B cell development. Hence, we hypothesized that SLAP and c-Cbl may cooperate during B cell development to regulate BCR levels. In mice deficient in both SLAP and c-Cbl, we found that B cell development is altered, suggesting that they function through intersecting pathways. To study the mechanism by which SLAP and c-Cbl alter BCR levels, we coexpressed them in a mature mouse B cell line (Bal-17). First we determined that SLAP associates with proximal components of the BCR complex after stimulation and internalization. Coexpression of SLAP and c-Cbl in Bal-17 led to decreased surface and total BCR levels. This decrease in BCR levels depended on intact Src homology 2 (SH2) and C-terminal domains of SLAP. In addition, a mutation in the SH2 domain of SLAP blocked its colocalization with c-Cbl and the BCR complex, whereas deletion of the C terminus did not affect its localization. Last, coexpression of SLAP and c-Cbl altered BCR complex recycling. This alteration in BCR complex recycling depended on enzymatically active c-Cbl and Src family kinases, as well as the intact SH2 and C-terminal domains of SLAP. These data suggest that SLAP has a conserved function in B and T cells by adapting c-Cbl to the antigen-receptor complex and targeting it for degradation.

Src-like adaptor protein (SLAP) regulates B cell receptor levels in a c-Cbl-dependent manner

PubMed Central

Dragone, Leonard L.; Myers, Margaret D.; White, Carmen; Gadwal, Shyam; Sosinowski, Tomasz; Gu, Hua; Weiss, Arthur

2006-01-01

Src-like adaptor protein (SLAP) and c-Cbl recently have been shown to cooperate in regulating T cell receptor (TCR) levels in developing T cells. SLAP also is expressed in developing B cells, and its deficiency leads to alterations in B cell receptor (BCR) levels and B cell development. Hence, we hypothesized that SLAP and c-Cbl may cooperate during B cell development to regulate BCR levels. In mice deficient in both SLAP and c-Cbl, we found that B cell development is altered, suggesting that they function through intersecting pathways. To study the mechanism by which SLAP and c-Cbl alter BCR levels, we coexpressed them in a mature mouse B cell line (Bal-17). First we determined that SLAP associates with proximal components of the BCR complex after stimulation and internalization. Coexpression of SLAP and c-Cbl in Bal-17 led to decreased surface and total BCR levels. This decrease in BCR levels depended on intact Src homology 2 (SH2) and C-terminal domains of SLAP. In addition, a mutation in the SH2 domain of SLAP blocked its colocalization with c-Cbl and the BCR complex, whereas deletion of the C terminus did not affect its localization. Last, coexpression of SLAP and c-Cbl altered BCR complex recycling. This alteration in BCR complex recycling depended on enzymatically active c-Cbl and Src family kinases, as well as the intact SH2 and C-terminal domains of SLAP. These data suggest that SLAP has a conserved function in B and T cells by adapting c-Cbl to the antigen-receptor complex and targeting it for degradation. PMID:17110436

T Cell Inactivation by Poxviral B22 Family Proteins Increases Viral Virulence

PubMed Central

Alzhanova, Dina; Hammarlund, Erika; Reed, Jason; Meermeier, Erin; Rawlings, Stephanie; Ray, Caroline A.; Edwards, David M.; Bimber, Ben; Legasse, Alfred; Planer, Shannon; Sprague, Jerald; Axthelm, Michael K.; Pickup, David J.; Lewinsohn, David M.; Gold, Marielle C.; Wong, Scott W.; Sacha, Jonah B.; Slifka, Mark K.; Früh, Klaus

2014-01-01

Infections with monkeypox, cowpox and weaponized variola virus remain a threat to the increasingly unvaccinated human population, but little is known about their mechanisms of virulence and immune evasion. We now demonstrate that B22 proteins, encoded by the largest genes of these viruses, render human T cells unresponsive to stimulation of the T cell receptor by MHC-dependent antigen presentation or by MHC-independent stimulation. In contrast, stimuli that bypass TCR-signaling are not inhibited. In a non-human primate model of monkeypox, virus lacking the B22R homologue (MPXVΔ197) caused only mild disease with lower viremia and cutaneous pox lesions compared to wild type MPXV which caused high viremia, morbidity and mortality. Since MPXVΔ197-infected animals displayed accelerated T cell responses and less T cell dysregulation than MPXV US2003, we conclude that B22 family proteins cause viral virulence by suppressing T cell control of viral dissemination. PMID:24832205

T cell inactivation by poxviral B22 family proteins increases viral virulence.

PubMed

Alzhanova, Dina; Hammarlund, Erika; Reed, Jason; Meermeier, Erin; Rawlings, Stephanie; Ray, Caroline A; Edwards, David M; Bimber, Ben; Legasse, Alfred; Planer, Shannon; Sprague, Jerald; Axthelm, Michael K; Pickup, David J; Lewinsohn, David M; Gold, Marielle C; Wong, Scott W; Sacha, Jonah B; Slifka, Mark K; Früh, Klaus

2014-05-01

Infections with monkeypox, cowpox and weaponized variola virus remain a threat to the increasingly unvaccinated human population, but little is known about their mechanisms of virulence and immune evasion. We now demonstrate that B22 proteins, encoded by the largest genes of these viruses, render human T cells unresponsive to stimulation of the T cell receptor by MHC-dependent antigen presentation or by MHC-independent stimulation. In contrast, stimuli that bypass TCR-signaling are not inhibited. In a non-human primate model of monkeypox, virus lacking the B22R homologue (MPXVΔ197) caused only mild disease with lower viremia and cutaneous pox lesions compared to wild type MPXV which caused high viremia, morbidity and mortality. Since MPXVΔ197-infected animals displayed accelerated T cell responses and less T cell dysregulation than MPXV US2003, we conclude that B22 family proteins cause viral virulence by suppressing T cell control of viral dissemination.

IL-22 promotes Fas expression in oligodendrocytes and inhibits FOXP3 expression in T cells by activating the NF-κB pathway in multiple sclerosis.

PubMed

Zhen, Jin; Yuan, Jun; Fu, Yongwang; Zhu, Runxiu; Wang, Meiling; Chang, Hong; Zhao, Yan; Wang, Dong; Lu, Zuneng

2017-02-01

Multiple sclerosis (MS) is characterized by an increase in interleukin-22 and Fas, and a decrease in FOXP3, among other factors. In this study, we examined patients with MS and healthy control subjects and used the experimental autoimmune encephalomyelitis (EAE) animal model to identify the effects of IL-22 on oligodendrocytes and T cells in MS development. In MS, the expression of Fas in oligodendrocytes and IL-22 in CD4 + CCR4 + CCR6 + CCR10 + T cells was enhanced. Ikaros and FOXP3 were both decreased in T cells. Depending on exogenous IL-22, Fas increased the phosphorylation of mitogen- and stress-activated protein kinase 1 and activated the nuclear factor-κB pathway in oligodendrocytes, leading to an increase in Fas and oligodendrocyte apoptosis. IL-22 decreased FOXP3 expression by activating NF-κB, and it further inhibited PTEN and Ikaros expression. Tregs reversed the functions of IL-22. Taken together, these findings help to elucidate the mechanisms of IL-22 in MS development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transcriptional Profiling of Antigen-Dependent Murine B Cell Differentiation and Memory Formation1

PubMed Central

Bhattacharya, Deepta; Cheah, Ming T.; Franco, Christopher B.; Hosen, Naoki; Pin, Christopher L.; Sha, William C.; Weissman, Irving L.

2015-01-01

Humoral immunity is characterized by the generation of Ab-secreting plasma cells and memory B cells that can more rapidly generate specific Abs upon Ag exposure than their naive counterparts. To determine the intrinsic differences that distinguish naive and memory B cells and to identify pathways that allow germinal center B cells to differentiate into memory B cells, we compared the transcriptional profiles of highly purified populations of these three cell types along with plasma cells isolated from mice immunized with a T-dependent Ag. The transcriptional profile of memory B cells is similar to that of naive B cells, yet displays several important differences, including increased expression of activation-induced deaminase and several antiapoptotic genes, chemotactic receptors, and costimulatory molecules. Retroviral expression of either Klf2 or Ski, two transcriptional regulators specifically enriched in memory B cells relative to their germinal center precursors, imparted a competitive advantage to Ag receptor and CD40-engaged B cells in vitro. These data suggest that humoral recall responses are more rapid than primary responses due to the expression of a unique transcriptional program by memory B cells that allows them to both be maintained at high frequencies and to detect and rapidly respond to antigenic re-exposure. PMID:17982071

Accumulation of cytolytic CD8{sup +} T cells in B16-melanoma and proliferation of mature T cells in TIS21-knockout mice after T cell receptor stimulation

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

Ryu, Min Sook; Woo, Min-Yeong; Department of Biomedical Sciences, The Graduate School, Ajou University

2014-10-01

In vivo and in vitro effects of TIS21 gene on the mature T cell activation and antitumor activities were explored by employing MO5 melanoma orthograft and splenocytes isolated from the TIS21-knockout (KO) mice. Proliferation and survival of mature T cells were significantly increased in the KO than the wild type (WT) cells, indicating that TIS21 inhibits the rate of mature T cell proliferation and its survival. In MO5 melanoma orthograft model, the KO mice recruited much more CD8{sup +} T cells into the tumors at around day 14 after tumor cell injection along with reduced tumor volumes compared with themore » WT. The increased frequency of granzyme B{sup +} CD8{sup +} T cells in splenocytes of the KO mice compared with the WT may account for antitumor-immunity of TIS21 gene in the melanoma orthograft. In contrast, reduced frequencies of CD107a{sup +} CD8{sup +} T cells in the splenocytes of KO mice may affect the loss of CD8{sup +} T cell infiltration in the orthograft at around day 19. These results indicate that TIS21 exhibits antiproliferative and proapoptotic effects in mature T cells, and differentially affects the frequencies of granzyme B{sup +} CD8{sup +} T-cells and CD107a{sup +} CD8{sup +} T-cells, thus transiently regulating in vivo anti-tumor immunity. - Highlights: • Constitutive expression of TIS21 in splenocytes and upregulation by TCR stimulation. • Proliferation of mature T-cells in spleen of TIS21KO mice after TCR stimulation. • Inhibition of cell death in mature T-cells of TIS21KO mice compared with the wild type. • Inhibition of melanoma growth in TIS21KO mice and CD8{sup +} T cell infiltration in tumor. • Reduction of CD 107{sup +}CD8{sup +} T cells, but increased granzyme B{sup +} CD8{sup +} T cells in TIS21KO mice.« less

B cells regulate thymic CD8+T cell differentiation in lupus-prone mice.

PubMed

Xing, Chen; Zhu, Gaizhi; Xiao, He; Fang, Ying; Liu, Xiaoling; Han, Gencheng; Chen, Guojiang; Hou, Chunmei; Shen, Beifen; Li, Yan; Ma, Ning; Wang, Renxi

2017-10-27

Previous studies have shown that under normal physiological conditions thymic B cells play a critical function in T cell negative selection. We tested the effect of thymic B cells on thymic T-cell differentiation in autoimmune diseases including systemic lupus erythematosus (SLE). We found that thymic B cells and CD8 - CD4 + and CD4 - CD8 + T cells increased, whereas CD4 + CD8 + T cells decreased in lupus-prone mice. Once B cells were reduced, the change was reversed. Furthermore, we found that B cells blocked thymic immature single positive (ISP) CD4 - CD8 + CD3 lo/- RORγt - T cells progression into CD4 + CD8 + T cells. Interestingly, we found a novel population of thymic immature T cells (CD4 - CD8 + CD3 lo RORγt + ) that were induced into mature CD4 - CD8 + CD3 + RORγt + T cells by B cells in lupus-prone mice. Importantly, we found that IgG, produced by thymic B cells, played a critical role in the differentiation of thymic CD8 + ISP and mature RORγt + CD8 + T cells in lupus-prone mice. In conclusion, B cells blocked the differentiation from thymic CD8 + ISP and induced the differentiation of a novel immature CD4 - CD8 + CD3 lo RORγt + T cells into mature RORγt + CD8 + T cells by secreting IgG antibody in lupus-prone mice.

Citric acid induces cell-cycle arrest and apoptosis of human immortalized keratinocyte cell line (HaCaT) via caspase- and mitochondrial-dependent signaling pathways.

PubMed

Ying, Tsung-Ho; Chen, Chia-Wei; Hsiao, Yu-Ping; Hung, Sung-Jen; Chung, Jing-Gung; Yang, Jen-Hung

2013-10-01

Citric acid is an alpha-hydroxyacid (AHA) widely used in cosmetic dermatology and skincare products. However, there is concern regarding its safety for the skin. In this study, we investigated the cytotoxic effects of citric acid on the human keratinocyte cell line HaCaT. HaCaT cells were treated with citric acid at 2.5-12.5 mM for different time periods. Cell-cycle arrest and apoptosis were investigated by 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining, flow cytometry, western blot and confocal microscopy. Citric acid not only inhibited proliferation of HaCaT cells in a dose-dependent manner, but also induced apoptosis and cell cycle-arrest at the G2/M phase (before 24 h) and S phase (after 24 h). Citric acid increased the level of Bcl-2-associated X protein (BAX) and reduced the levels of B-cell lymphoma-2 (BCL-2), B-cell lymphoma-extra large (BCL-XL) and activated caspase-9 and caspase-3, which subsequently induced apoptosis via caspase-dependent and caspase-independent pathways. Citric acid also activated death receptors and increased the levels of caspase-8, activated BH3 interacting-domain death agonist (BID) protein, Apoptosis-inducing factor (AIF), and Endonuclease G (EndoG). Therefore, citric acid induces apoptosis through the mitochondrial pathway in the human keratinocyte cell line HaCaT. The study results suggest that citric acid is cytotoxic to HaCaT cells via induction of apoptosis and cell-cycle arrest in vitro.

Cognate interactions between helper T cells and B cells. IV. Requirements for the expression of effector phase activity by helper T cells.

PubMed

Bartlett, W C; McCann, J; Shepherd, D M; Roy, M; Noelle, R J

1990-12-15

After activation with anti-CD3, activated Th (THCD3), but not resting Th, fixed with paraformaldehyde induce B cell RNA synthesis when co-cultured with resting B cells. This activity is expressed by Th of both Th1 and Th2 subtypes, as well as a third Th clone that is not classified into either subtype. It is proposed that anti-CD3 activation of Th results in the expression of Th membrane proteins that trigger B cell cycle entry. Kinetic studies reveal that 4 to 8 h of activation with anti-CD3 is sufficient for ThCD3 to express B cell-activating function. However, activation of Th with anti-CD3 for extended periods of time results in reduced Th effector activity. Inhibition of Th RNA synthesis during the anti-CD3 activation period ablates the ability of ThCD3 to induce B cell cycle entry. This indicates that de novo synthesis of proteins is required for ThCD3 to express effector function. The ability of fixed ThCD3 to induce entry of B cell into cycle is not due to an increase in expression of CD3, CD4, LFA-1, ICAM-1, class I MHC or Thy-1. Other forms of Th activation (PMA and A23187, Con A) also induced Th effector function. Furthermore, purified plasma membranes from anti-CD3 activated, but not resting Th, induced resting B cells to enter cycle. The addition of IL-4, but not IL-2, IL-5, or IFN-gamma amplified the DNA synthetic response of B cells stimulated with PM from activated Th. Taken together these data indicate that de novo expression of Th surface proteins on activated Th is required for Th to induce B cell cycle entry into G1 and the addition of IL-4 is required for the heightened progression into S phase.

SAP modulates B cell functions in a genetic background-dependent manner.

PubMed

Detre, Cynthia; Yigit, Burcu; Keszei, Marton; Castro, Wilson; Magelky, Erica M; Terhorst, Cox

2013-06-01

Mutations affecting the SLAM-associated protein (SAP) are responsible for the X-linked lympho-proliferative syndrome (XLP), a severe primary immunodeficiency syndrome with disease manifestations that include fatal mononucleosis, B cell lymphoma and dysgammaglobulinemia. It is well accepted that insufficient help by SAP-/- CD4+ T cells, in particular during the germinal center reaction, is a component of dysgammaglobulinemia in XLP patients and SAP-/- animals. It is however not well understood whether in XLP patients and SAP-/- mice B cell functions are affected, even though B cells themselves do not express SAP. Here we report that B cell intrinsic responses to haptenated protein antigens are impaired in SAP-/- mice and in Rag-/- mice into which B cells derived from SAP-/- mice together with wt CD4+ T cells had been transferred. This impaired B cells functions are in part depending on the genetic background of the SAP-/- mouse, which affects B cell homeostasis. Surprisingly, stimulation with an agonistic anti-CD40 causes strong in vivo and in vitro B cell responses in SAP-/- mice. Taken together, the data demonstrate that genetic factors play an important role in the SAP-related B cell functions. The finding that anti-CD40 can in part restore impaired B cell responses in SAP-/- mice, suggests potentially novel therapeutic interventions in subsets of XLP patients. Copyright © 2013 Elsevier B.V. All rights reserved.

Decoy receptor 3 suppresses TLR2-mediated B cell activation by targeting NF-κB.

PubMed

Huang, Zi-Ming; Kang, Jhi-Kai; Chen, Chih-Yu; Tseng, Tz-Hau; Chang, Chien-Wen; Chang, Yung-Chi; Tai, Shyh-Kuan; Hsieh, Shie-Liang; Leu, Chuen-Miin

2012-06-15

Decoy receptor 3 (DcR3) is a soluble protein in the TNFR superfamily. Its known ligands include Fas ligand, homologous to lymphotoxin, showing inducible expression, and competing with HSV glycoprotein D for herpes virus entry mediator, a receptor expressed by T lymphocytes, TNF-like molecule 1A, and heparan sulfate proteoglycans. DcR3 has been reported to modulate the functions of T cells, dendritic cells, and macrophages; however, its role in regulating B cell activation is largely unknown. In this study, we found that the DcR3.Fc fusion protein bound to human and mouse B cells and suppressed the activation of B cells. DcR3.Fc attenuated Staphylococcus aureus, IgM-, Pam(3)CSK(4)-, and LPS-mediated B cell proliferation but did not affect cytokine-induced B cell growth. In the presence of these mitogens, DcR3.Fc did not induce B cell apoptosis, suggesting that DcR3 may inhibit the signal(s) important for B cell activation. Because the combination of Fas.Fc, LT-βR.Fc (homologous to lymphotoxin, showing inducible expression, and competing with HSV glycoprotein D for herpes virus entry mediator, a receptor expressed by T lymphocytes receptor), and DR3.Fc (TNF-like molecule 1A receptor) did not suppress B cell proliferation and because the biological effect of DcR3.Fc on B cells was not blocked by heparin, we hypothesize that a novel ligand(s) of DcR3 mediates its inhibitory activity on B cells. Moreover, we found that TLR2-stimulated NF-κB p65 activation and NF-κB-driven luciferase activity were attenuated by DcR3.Fc. The TLR2-induced cytokine production by B cells was consistently reduced by DcR3. These results imply that DcR3 may regulate B cell activation by suppressing the activation of NF-κB.

Growth-dependent catalase localization in Exiguobacterium oxidotolerans T-2-2T reflected by catalase activity of cells.

PubMed

Hanaoka, Yoshiko; Takebe, Fumihiko; Nodasaka, Yoshinobu; Hara, Isao; Matsuyama, Hidetoshi; Yumoto, Isao

2013-01-01

A psychrotolerant and H2O2-resistant bacterium, Exiguobacterium oxidotolerans T-2-2(T), exhibits extraordinary H2O2 resistance and produces catalase not only intracellularly but also extracellularly. The intracellular and extracellular catalases exhibited the same enzymatic characteristics, that is, they exhibited the temperature-dependent activity characteristic of a cold-adapted enzyme, their heat stabilities were similar to those of mesophilic enzymes and very high catalytic intensity. In addition, catalase gene analysis indicated that the bacterium possessed the sole clade 1 catalase gene corresponding to intracellular catalase. Hence, intracellular catalase is secreted into the extracellular space. In addition to intracellular and extracellular catalases, the inner circumference of the cells showed the localization of catalase in the mid-stationary growth phase, which was observed by immunoelectron microscopy using an antibody against the intracellular catalase of the strain. The cells demonstrated higher catalase activity in the mid-stationary growth phase than in the exponential growth phase. The catalase localized in the inner circumference can be dissociated by treatment with Tween 60. Thus, the localized catalase is not tightly bound to the inner circumference of the cells and may play a role in the oxidative defense of the cells under low metabolic state.

Growth-Dependent Catalase Localization in Exiguobacterium oxidotolerans T-2-2T Reflected by Catalase Activity of Cells

PubMed Central

Hanaoka, Yoshiko; Takebe, Fumihiko; Nodasaka, Yoshinobu; Hara, Isao; Matsuyama, Hidetoshi; Yumoto, Isao

2013-01-01

A psychrotolerant and H2O2-resistant bacterium, Exiguobacterium oxidotolerans T-2-2T, exhibits extraordinary H2O2 resistance and produces catalase not only intracellularly but also extracellularly. The intracellular and extracellular catalases exhibited the same enzymatic characteristics, that is, they exhibited the temperature-dependent activity characteristic of a cold-adapted enzyme, their heat stabilities were similar to those of mesophilic enzymes and very high catalytic intensity. In addition, catalase gene analysis indicated that the bacterium possessed the sole clade 1 catalase gene corresponding to intracellular catalase. Hence, intracellular catalase is secreted into the extracellular space. In addition to intracellular and extracellular catalases, the inner circumference of the cells showed the localization of catalase in the mid-stationary growth phase, which was observed by immunoelectron microscopy using an antibody against the intracellular catalase of the strain. The cells demonstrated higher catalase activity in the mid-stationary growth phase than in the exponential growth phase. The catalase localized in the inner circumference can be dissociated by treatment with Tween 60. Thus, the localized catalase is not tightly bound to the inner circumference of the cells and may play a role in the oxidative defense of the cells under low metabolic state. PMID:24204687

T-cell/histiocyte-rich large B-cell lymphoma of stomach.

PubMed

Barut, Figen; Kandemir, Nilufer Onak; Gun, Banu Dogan; Ozdamar, Sukru Oguz

2016-07-01

T-cell/histiocyte-rich large B-cell lymphoma is an unusually encountered lymphoid neoplasm of stomach with aggressive course, and is an uncommon morphologic variant of diffuse large B-cell lymphoma. An ulcerated mass, 7x5x1 cm in size was observed within the gastrectomy specimen of a 76-year-old female patient. In cross sections, besides mature lymphoid cells displaying T-cell phenotype, a neoplastic formation composed of large, pleomorphic atypical lymphoid cells with, prominent nucleoli, vesicular nuclei and abundant eosinophilic cytoplasm displaying B-cell phenotype were observed. Meanwhile, histiocyte-like mononuclear cells and Reed-Sternberg-like multinuclear cells expressing CD68 and Mac387 were also observed. The diagnosis of the case was T cell/histiocyte-rich large B-cell lymphoma. This rarely encountered neoplasm should be kept in mind in the differential diagnosis of primary gastric lymphomas.