scholarly journals Synaptic Clusters of MHC Class II Molecules Induced on DCs by Adhesion Molecule–mediated Initial T-Cell Scanning

2005 ◽  
Vol 16 (7) ◽  
pp. 3314-3322 ◽  
Author(s):  
Hortensia de la Fuente ◽  
María Mittelbrunn ◽  
Lorena Sánchez-Martín ◽  
Miguel Vicente-Manzanares ◽  
Amalia Lamana ◽  
...  
Keyword(s):  
T Cells ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Regulatory Pathway ◽  
Immune Synapse ◽  
Mhc Ii ◽  
Cytoskeleton Reorganization ◽  
Adhesive Contacts ◽  
Enhance Antigen Presentation ◽  
Mhc Class Ii Molecules

Initial adhesive contacts between T lymphocytes and dendritic cells (DCs) facilitate recognition of peptide-MHC complexes by the TCR. In this report, we studied the dynamic behavior of adhesion and Ag receptors on DCs during initial contacts with T-cells. Adhesion molecules LFA-1- and ICAM-1,3-GFP as well as MHC class II-GFP molecules were very rapidly concentrated at the DC contact area. Binding of ICAM-3, and ICAM-1 to a lesser extent, to LFA-1 expressed by mature but not immature DC, induced MHC-II clustering into the immune synapse. Also, ICAM-3 binding to DC induced the activation of the Vav1-Rac1 axis, a regulatory pathway involved in actin cytoskeleton reorganization, which was essential for MHC-II clustering on DCs. Our results support a model in which ICAM-mediated MHC-II clustering on DC constitutes a priming mechanism to enhance antigen presentation to T-cells.

scholarly journals Major Histocompatibility Complex Class II+ Invariant Chain Negative Breast Cancer Cells Present Unique Peptides that Activate Tumor-specific T Cells from Breast Cancer Patients

2012 ◽  
Vol 11 (11) ◽  
pp. 1457-1467 ◽  
Author(s):  
Olesya Chornoguz ◽  
Alexei Gapeev ◽  
Michael C. O'Neill ◽  
Suzanne Ostrand-Rosenberg
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
Cancer Cells ◽  
Cancer Patients ◽  
Mhc Class Ii ◽  
Breast Cancer Cells ◽  
Class Ii ◽  
Breast Cancer Patients ◽  
Mhc Ii ◽  
Peptide Loading

The major histocompatibility complex (MHC) class II-associated Invariant chain (Ii) is present in professional antigen presenting cells where it regulates peptide loading onto MHC class II molecules and the peptidome presented to CD4+ T lymphocytes. Because Ii prevents peptide loading in neutral subcellular compartments, we reasoned that Ii− cells may present peptides not presented by Ii+ cells. Based on the hypothesis that patients are tolerant to MHC II-restricted tumor peptides presented by Ii+ cells, but will not be tolerant to novel peptides presented by Ii− cells, we generated MHC II vaccines to activate cancer patients' T cells. The vaccines are Ii− tumor cells expressing syngeneic HLA-DR and the costimulatory molecule CD80. We used liquid chromatography coupled with mass spectrometry to sequence MHC II-restricted peptides from Ii+ and Ii− MCF10 human breast cancer cells transfected with HLA-DR7 or the MHC Class II transactivator CIITA to determine if Ii− cells present novel peptides. Ii expression was induced in the HLA-DR7 transfectants by transfection of Ii, and inhibited in the CIITA transfectants by RNA interference. Peptides were analyzed and binding affinity predicted by artificial neural net analysis. HLA-DR7-restricted peptides from Ii− and Ii+ cells do not differ in size or in subcellular location of their source proteins; however, a subset of HLA-DR7-restricted peptides of Ii− cells are not presented by Ii+ cells, and are derived from source proteins not used by Ii+ cells. Peptides from Ii− cells with the highest predicted HLA-DR7 binding affinity were synthesized, and activated tumor-specific HLA-DR7+ human T cells from healthy donors and breast cancer patients, demonstrating that the MS-identified peptides are bonafide tumor antigens. These results demonstrate that Ii regulates the repertoire of tumor peptides presented by MHC class II+ breast cancer cells and identify novel immunogenic MHC II-restricted peptides that are potential therapeutic reagents for cancer patients.

scholarly journals Major histocompatibility complex-restricted recognition of retroviral superantigens by V beta 17+ T cells.

1992 ◽  
Vol 176 (1) ◽  
pp. 275-280 ◽  
Author(s):  
M A Blackman ◽  
F E Lund ◽  
S Surman ◽  
R B Corley ◽  
D L Woodland
Keyword(s):  
T Cells ◽  
Major Histocompatibility Complex ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Major Histocompatibility ◽  
Direct Role ◽  
Histocompatibility Complex ◽  
Class Ii Mhc ◽  
Mhc Class Ii Molecules

It has been established that at least some V beta 17+ T cells interact with an endogenous superantigen encoded by the murine retrovirus, Mtv-9. To analyze the role of major histocompatibility complex (MHC) class II molecules in presenting the Mtv-9 encoded superantigen, vSAG-9 to V beta 17+ hybridomas, a panel of nine hybridomas was tested for their ability to respond to A20/2J (H-2d) and LBK (H-2a) cells which had been transfected with the vSAG-9 gene. Whereas some of the hybridomas recognized vSAG-9 exclusively in the context of H-2a, other hybridomas recognized vSAG-9 exclusively in the context of H-2d or in the context of both H-2d and H-2a. These results suggest that: (a) the class II MHC molecule plays a direct role in the recognition of retroviral superantigen by T cells, rather than serving simply as a platform for presentation; and, (b) it is likely that components of the TCR other than V beta are involved in the vSAG-9/TCR/class II interaction.

scholarly journals Activation of Human Dendritic Cells Is Modulated by Components of the Outer Membranes of Neisseria meningitidis

2003 ◽  
Vol 71 (10) ◽  
pp. 5590-5597 ◽  
Author(s):  
Tamara Al-Bader ◽  
Myron Christodoulides ◽  
John E. Heckels ◽  
Judith Holloway ◽  
Amanda E. Semper ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Neisseria Meningitidis ◽  
Mrna Expression ◽  
Mhc Class Ii ◽  
Human Monocyte ◽  
Class Ii ◽  
Effective Vaccine ◽  
Tlr4 Mrna ◽  
Mhc Class Ii Molecules

ABSTRACT Neisseria meningitidis serogroup B is a major cause of life-threatening meningitis and septicemia worldwide, and no effective vaccine is available. Initiation of innate and acquired immune responses to N. meningitidis is likely to be dependent on cellular responses of dendritic cells (DC) to antigens present in the outer membrane (OM) of the meningococcus. In this study, the responses of human monocyte-derived DC (mo-DC) to OM isolated from parent (lipopolysaccharide [LPS]-replete) meningococci and from a mutant deficient in LPS were investigated. Parent OM selectively up-regulated Toll-like receptor 4 (TLR4) mRNA expression and induced mo-DC maturation, as reflected by increased production of chemokines, proinflammatory cytokines, and CD83, CD80, CD86, CD40, and major histocompatibility complex (MHC) class II molecules. In contrast, LPS-deficient OM selectively up-regulated TLR2 mRNA expression and induced moderate increases in both cytokine production and expression of CD86 and MHC class II molecules. Preexposure to OM, with or without LPS, augmented the allostimulatory properties of mo-DC, which induced proliferation of naive CD4+ CD45RA+ T cells. In addition, LPS-replete OM induced a greater gamma interferon/interleukin-13 ratio in naive T cells, whereas LPS-deficient OM induced the reverse profile. These data demonstrate that components of the OM, other than LPS, are also likely to be involved in determining the levels of DC activation and the nature of the T-helper immune response.

scholarly journals In Vivo Evidence for the Contribution of Human Histocompatibility Leukocyte Antigen (Hla)-Dq Molecules to the Development of Diabetes

2000 ◽  
Vol 191 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Li Wen ◽  
F. Susan Wong ◽  
Jie Tang ◽  
Ning-Yuan Chen ◽  
Martha Altieri ◽  
...  
Keyword(s):  
T Cells ◽  
Transgenic Mice ◽  
Mhc Class Ii ◽  
Spontaneous Diabetes ◽  
Class Ii ◽  
Β Cells ◽  
Leukocyte Antigen ◽  
Hla Dqa1 ◽  
Mhc Class Ii Molecules

Although DQA1*0301/DQB1*0302 is the human histocompatibility leukocyte antigen (HLA) class II gene most commonly associated with human type 1 diabetes, direct in vivo experimental evidence for its diabetogenic role is lacking. Therefore, we generated C57BL/6 transgenic mice that bear this molecule and do not express mouse major histocompatibility complex (MHC) class II molecules (DQ8+/mII−). They did not develop insulitis or spontaneous diabetes. However, when DQ8+/mII− mice were bred with C57BL/6 mice expressing costimulatory molecule B7-1 on β cells (which normally do not develop diabetes), 81% of the DQ8+/mII−/B7-1+ mice developed spontaneous diabetes. The diabetes was accompanied by severe insulitis composed of both T cells (CD4+ and CD8+) and B cells. T cells from the diabetic mice secreted large amounts of interferon γ, but not interleukin 4, in response to DQ8+ islets and the putative islet autoantigens, insulin and glutamic acid decarboxylase (GAD). Diabetes could also be adoptively transferred to irradiated nondiabetic DQ8+/mII−/B7-1+ mice. In striking contrast, none of the transgenic mice in which the diabetes protective allele (DQA1*0103/DQB1*0601, DQ6 for short) was substituted for mouse MHC class II molecules but remained for the expression of B7-1 on pancreatic β cells (DQ6+/mII−/B7-1+) developed diabetes. Only 7% of DQ−/mII−/B7-1+ mice developed diabetes at an older age, and none of the DQ−/mII+/B7-1+ mice or DQ8+/mII+/B7-1+ mice developed diabetes. In conclusion, substitution of HLA-DQA1*0301/DQB1*0302, but not HLA-DQA1*0103/DQB1*0601, for murine MHC class II provokes autoimmune diabetes in non–diabetes-prone rat insulin promoter (RIP).B7-1 C57BL/6 mice. Our data provide direct in vivo evidence for the diabetogenic effect of this human MHC class II molecule and a unique “humanized” animal model of spontaneous diabetes.

scholarly journals The importance of the back–signal from T cells into antigen–presenting cells in determining susceptibility to parasites

1997 ◽  
Vol 352 (1359) ◽  
pp. 1327-1330 ◽  
Author(s):  
Brigitte Müller ◽  
Avrion Mitchison
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Activated T Cells ◽  
Ifn Gamma ◽  
Parasite Infections ◽  
Antigen Presenting ◽  
Mhc Class Ii Genes ◽  
Mhc Class Ii Molecules

It has long been known that certain MHC class II genes can dominantly suppress immune responses and so increase susceptibility to parasite infections, but the mechanism has been unclear. Recent work has revealed one way in which this form of suppression may operate through gating by MHC class II molecules of the back–signal from activated T cells into macrophages. The two known suppressive genes of the mouse are expressed in macrophages more extensively than are other class II genes. This is asscociated with suppresion of IL–4 production resulting, we infer, from overproduction in the macrophages of IL–12, the counter–cytokine to IL–4. The lack of IL–4 may itself be immunosuppressive, even for Th2 responses, and excess IL–12 can overinduce the antiproliferative cytokine IFN–gamma. Although this mechanism requires further substantiation, we believe that it offers a reasonable answer to an old conundrum.

scholarly journals Major Histocompatibility Complex Class II-Independent Generation of Neutralizing Antibodies against T-Cell-Dependent Borrelia burgdorferi Antigens Presented by Dendritic Cells: Regulation by NK and γδ T Cells

2001 ◽  
Vol 69 (4) ◽  
pp. 2407-2415 ◽  
Author(s):  
M. Lamine Mbow ◽  
Nordin Zeidner ◽  
Robert D. Gilmore ◽  
Marc Dolan ◽  
Joseph Piesman ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Major Histocompatibility Complex ◽  
Borrelia Burgdorferi ◽  
Mhc Class Ii ◽  
Γδ T Cells ◽  
Humoral Response ◽  
Class Ii ◽  
Histocompatibility Complex ◽  
Mhc Class Ii Molecules

ABSTRACT We previously showed that adoptive transfer of Borrelia burgdorferi-pulsed dendritic cells (DCs) into syngeneic mice protects animals from challenge with tick-transmitted spirochetes. Here, we demonstrate that the protective immune response is antibody (Ab) dependent and does not require the presence of major histocompatibility complex (MHC) class II molecules on DCs. Mice sensitized with B. burgdorferi-pulsed MHC class II-deficient (MHC class II−/−) DCs mounted a humoral response against protective antigens, includingB. burgdorferi outer surface protein A (OspA) and OspC. B-cell help for the generation of neutralizing anti-OspC immunoglobulin G Abs could be provided by γδ T cells. In contrast, anti-OspA Ab production required the presence of αβ T cells, although this pathway could be independent of MHC class II molecules on antigen-presenting cells. Moreover, depletion of NK cells prior to transfer of antigen-pulsed MHC class II−/− DCs resulted in significant increases in the levels of neutralizing Abs induced by DCs. Altogether, these data suggest that the initial interactions between DCs and innate immune cells, such as γδ and NK cells, can influence the generation of a protective humoral response againstB. burgdorferi antigens.

Peripheral Pool of CD8+T-Cells Contains Lymphocytes with Antigen-Specific Receptors That Recognize Syngeneic MHC Class II Molecules

2004 ◽  
Vol 35 (3) ◽  
pp. 142-147
Author(s):  
L. A. Pobezinsky ◽  
E. L. Pobezinskaya ◽  
T. S. Grinenko ◽  
A. V. Chervonskii ◽  
D. B. Kazansky
Keyword(s):  
T Cells ◽  
Mhc Class Ii ◽  
Cd8 T Cells ◽  
Class Ii ◽  
Specific Receptors ◽  
Mhc Class Ii Molecules

Humanized E17 Hemophilic Mice Are a Major Breakthrough in the Design of New Preclinical Models for Developing Factor VIII Products with Reduced Immunogenicity.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 782-782 ◽  
Author(s):  
Birgit M. Reipert ◽  
Christina Hausl ◽  
Maria Sasgary ◽  
Maria Schuster ◽  
Rafi U. Ahmad ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Factor Viii ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Plasma Cells ◽  
Hemophilia A ◽  
Class Ii ◽  
Mhc Class Ii Molecules

Abstract MHC class II molecules are crucial for regulating adaptive immune responses against self and foreign protein antigens. They determine the antigenic peptides that are presented to CD4+ T cells and are essential for shaping the CD4+ T-cell repertoire in the thymus. Thus, the structure of MHC class II molecules is a major determinant for protein antigen immunogenicity. Structural differences between murine and human MHC class II complexes fundamentally limit the use of conventional murine hemophilia A models for dissecting immune responses to human factor VIII and developing new factor VIII products with reduced immunogenicity. To overcome this limitation, we humanized the murine E17 model of hemophilia A by introducing the human MHC class II haplotype HLA-DRB1*1501 on the background of a complete knockout of all murine MHC class II genes. Any anti-FVIII antibody response in this new humanized hemophilia A model is driven by CD4+ T cells that recognize FVIII-derived peptides that are presented by human HLA-DRB1*1501. The MHC class II haplotype HLA-DRB1*1501 is particularly relevant for the situation in hemophilia A patients because it is found in about 25% of Caucasians and 32% of Africans and has been shown to be associated with an increased risk that patients with severe hemophilia A have for developing FVIII inhibitors. We validated the relevance of this new model by asking the question whether HLA-DRB1*1501 hemophilic E17 mice develop FVIII inhibitors that are similar to those observed in patients with hemophilia A. Furthermore, we wanted to show that anti-FVIII antibody responses in these mice depend on the expression of the human DRB1*1501 molecule. Mice were treated with 8 intravenous doses of human FVIII and tested for anti-FVIII antibodies, anti-FVIII antibody-producing plasma cells and FVIII-specific T cells. About 90% of all humanized hemophilic E17 mice tested developed anti-FVIII antibodies that were similar to FVIII inhibitors found in patients. These antibodies were not restricted isotypically and contained mainly IgG1, IgG2a and IgG2b antibodies. Detection of antibodies in the circulation correlated with the presence of anti-FVIII antibody-producing plasma cells in the spleen. Development of anti-FVIII antibodies depended on the activation of FVIII-specific T cells and strictly depended on the expression of the HLA-DRB1*1501 molecule. Mice that did not express any MHC class II molecules did not develop anti-FVIII antibodies. We conclude that this new humanized E17 model for hemophilia A is a major advance towards developing suitable animal models needed to design future immunomodulatory strategies for patients with FVIII inhibitors and develop new FVIII products with reduced immunogenicity. Furthermore, it provides a tool for identifying T-cell epitopes of human FVIII restricted by MHC class II molecules that can be used for monitoring FVIII-specific T cells in patients who receive replacement therapy with FVIII products.

IFN-γ/STAT1-Dependent Regulation Of Antigen Presenting Cell (APC) Function: Role In Graft-Versus-Host Disease (GVHD)

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3252-3252
Author(s):  
Caisheng Lu ◽  
Huihui Ma ◽  
Shirong Li ◽  
Suzanne Lentzsch ◽  
Markus Mapara
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Wild Type ◽  
Mhc Ii ◽  
Allogeneic Bmt ◽  
Stat1 Signaling ◽  
Ifn Γ ◽  
Cd40 Expression

Abstract Interferon-gamma (IFN-γ) is a pleiotropic cytokine that has diverse activities in mediating host defense and immunopathology and is involved in both innate an adaptive immunity. Furthermore, IFN-γ has been shown to be a key regulator of GVHD. STAT1 is the major downstream signal transducer for IFN-γ. IFN-γ has been shown to up-regulate MHC class II expression on macrophages and dendritic cells. In this study, we unexpectedly observed that STAT1-deficient mouse bone marrow-derived dendritic cells (BM-DCs) displayed significantly increased MHC class II, CD86, CD80, CD40 expression compared to wild type BM-DCs upon LPS stimulation. To determine whether these LPS-maturated STAT1-/- BM-DCs are functional, freshly isolated pan-T cells from BALB/c (H2d) mice were stimulated with either irradiated LPS-maturated STAT1+/+ or STAT1-/- BMDCs from 129Sv [H2b] mice at different DC/Responder ratios for 5 days. Pan-T cell proliferation was measured using by 3H-incorporation or in separate assays by CFSE dilution. Both proliferation assays clearly demonstrated that STAT1-/- BM-DCs were significantly more potent stimulators in Mixed Lymphocyte Reaction (MLR) assays compared to STAT1+/+ BM-DCs. Further studies demonstrated that this increased surface MHC II expression was also observed in LPS-stimulated IFNγR-/- BM-DCs or on wild type BM-DCs treated with neutralizing IFNγ Abs but not in LPS-treated IFNα-R-/- BM-DCs. STAT1 deficient DCs have been reported to be defective in IL-12 production upon stimulation with various Toll-like receptors (TLRs). However, we were able to observe that STAT1-/- BM-DCs had increased CD40 expression after LPS maturation, and more importantly, STAT1 deficient BM-DCs had significantly increased IL-12 production upon treatment with CD40-ligand. These data suggest that STAT1 deficiency in LPS-stimulated DCs results not only in increased expression of MHC class II and costimulatory molecules, but also in enhanced CD40-dependent IL-12 production promoting generation of Th1 and Tc1 cell of wildtype responder cells. To test the influence of IFNγ/STAT1 deficiency in host APC on GVHD induction, wild type or STAT1-deficient 129 mice (H2b) underwent allogeneic Bone Marrow Transplantation (BMT) following lethal irradiation (1044 rad) receiving BALB/c spleen cells. 129.STAT1-/- recipients had significantly accelerated GVHD mortality (MST 8 days vs. 5 days, log rank test p=0.004) compared with wild type recipients. In contrast, STAT1-deficient syngeneic controls did not show enhanced mortality or morbidity ruling out that the observed accelerated mortality following allogeneic BMT was due to conditioning toxicity. On day+4 post-BMT animals were sacrificed and splenocytes were analyzed by flow cytometry. We could observe a significantly enhanced expansion and activation of donor CD4 and CD8 T cells in STAT1-/- recipients. Importantly, the increased MHC II expression was confirmed in host CD11b+ and CD11c+ cell populations. To clarify that STAT1 deficiency in host APCs do contribute to increased GVHD induction, we generated STAT1-/-→STAT1+/+, and STAT1+/+→STAT1+/+ radiation chimeric mice as recipients so that only the hematopoietic cells were STAT1 deficient. We again observed significantly increased GVHD mortality and increased activation of fully MHC-mismatched donor T cells in STAT1-/-→STAT1+/+ recipients following allogeneic BMT and GVHD induction. Similar results i.e. increased GVHD mortality, increased donor cell activation and increased MHC II expression on host CD11c+, B220+ cells were also found in IFNγR-/- recipient mice when compared with control mice following full MHC-mismatched allogeneic BMT. In summary our data reveal previously unknown effects of IFNγ/STAT1 signaling on APCs function suggesting that LPS-driven maturation of APC’s is negatively regulated by IFNγ/STAT1 leading to enhanced expression of MHC class II, costimulatory molecules and responsiveness to CD40-ligation and subsequent IL-12 production in the absence of STAT1. Furthermore, our results explain the accelerated GVHD induction and demonstrate that IFN-γ/STAT1 signaling in host APC mitigates the development of GVHD. Disclosures: Lentzsch: Celgene: Research Funding.

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