scholarly journals Generation of PLZF+ CD4+ T cells via MHC class II–dependent thymocyte–thymocyte interaction is a physiological process in humans

2009 ◽  
Vol 207 (1) ◽  
pp. 237-246 ◽  
Author(s):  
You Jeong Lee ◽  
Yoon Kyung Jeon ◽  
Byung Hyun Kang ◽  
Doo Hyun Chung ◽  
Chung-Gyu Park ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Zinc Finger Protein ◽  
Cell Subset ◽  
Cell Receptor ◽  
Class Ii ◽  
Inkt Cells ◽  
Mhc Class Ii Molecules

Human thymocytes, unlike mouse thymocytes, express major histocompatibility complex (MHC) class II molecules on their surface, especially during the fetal and perinatal stages. Based on this observation, we previously identified a novel developmental pathway for the generation of CD4+ T cells via interactions between MHC class II–expressing thymocytes (thymocyte–thymocyte [T–T] interactions) with a transgenic mouse system. However, the developmental dissection of this T–T interaction in humans has not been possible because of the lack of known cellular molecules specific for T–T CD4+ T cells. We show that promyelocytic leukemia zinc finger protein (PLZF) is a useful marker for the identification of T–T CD4+ T cells. With this analysis, we determined that a substantial number of fetal thymocytes and splenocytes express PLZF and acquire innate characteristics during their development in humans. Although these characteristics are quite similar to invariant NKT (iNKT) cells, they clearly differ from iNKT cells in that they have a diverse T cell receptor repertoire and are restricted by MHC class II molecules. These findings define a novel human CD4+ T cell subset that develops via an MHC class II–dependent T–T interaction.

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.

Antigen presentation by mouse CD4+ T cells involving acquired MHC class II:peptide complexes: another mechanism to limit clonal expansion?

Blood ◽  
2003 ◽  
Vol 101 (7) ◽  
pp. 2704-2710 ◽  
Author(s):  
Julia Y. S. Tsang ◽  
Jian Guo Chai ◽  
Robert Lechler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Antigen Presentation ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Interleukin 2 ◽  
Clonal Expansion ◽  
Class Ii ◽  
Hybridoma Cells ◽  
Mhc Class Ii Molecules

Antigen presentation by activated human and rat CD4+ T cells has long been known to induce hyporesponsiveness due to a combination of anergy and apoptosis. It has been assumed that no such phenomenon occurs in mice due to the inability of mouse T cells to synthesize major histocompatibility complex (MHC) class II molecules. There have been several recent descriptions of the transfer of molecules, including MHC molecules, from antigen-presenting cells (APCs) to T cells. Here, we describe the acquisition of MHC class II molecules by T-cell receptor (TCR)–transgenic T cells and T-hybridoma cells following culture with APCs. Acquisition was markedly enhanced by T-cell activation either due to cognate recognition of antigen or anti-CD3 activation. When activation was induced by antigen recognition, preferential acquisition of complexes of class II molecules displaying cognate peptide was observed; in contrast, following activation by anti-CD3 the acquisition of class II molecules was MHC unrestricted. T cells that had acquired MHC class II:peptide complexes were able to act as APCs and induced proliferation and interleukin-2 secretion by resting T cells. However, when activated T cells that had acquired MHC class II:peptide complexes engaged in T:T interactions, this led to an increase in apoptosis and the induction of hyporesponsiveness. These results raise the possibility that the acquisition of MHC class II:peptide complexes by T cells during an immune response may serve to limit clonal expansion, including that induced by alloantigen following tissue or stem cell transplantation.

A T Cell Receptor Signaling Mutant Reveals Two Distinct Populations of IL-17 Producing CD4+ T Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 186-186
Author(s):  
Jiyeon S Kim ◽  
Jennifer E Smith-Garvin ◽  
Martha S Jordan ◽  
Gary A Koretzky
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Th17 Cells ◽  
Critical Role ◽  
Cell Receptor ◽  
Class Ii ◽  
Interleukin 17

Abstract Abstract 186 Interleukin-17 (IL-17) producing CD4+ T cells (Th17 cells) are essential for immune responses in mucosal and epithelial sites which are the first line of host defense. Th17 cells play a critical role in the pathogenesis of many inflammatory and autoimmune diseases, and the role of IL-17 and Th17 cells in cancer has recently become the focus of extensive investigation. Most studies to date have focused on elucidating the cell extrinsic requirements for differentiation of Th17 cells from naïve CD4+ T cells in peripheral effector sites. Here we report an unconventional population of Th17 cells, “natural Th17 cells” (nTh17), that acquire effector function during development in the thymus, thereby distinguishing them from conventional Th17 cells which require antigen encounter and differentiation in the periphery. We show that these nTh17 cells are present and indeed develop in the thymus using fetal thymic organ culture. nTh17 cells express surface markers consistent with an innate and/or activated phenotype and their development is dependent on selection by MHC class II in the thymus. Yet unlike conventional CD4+ T cells, MHC class II expression on thymic cortical epithelium is not sufficient for their development, rather expression on medullary epithelium is necessary. In addition, T cell receptor (TCR) repertoire analysis of nTh17 cells revealed unique characteristics in TCR gene usage compared to conventional Th17 cells. A mouse model with a mutation in the TCR signaling protein SLP76 (SLP76 Y145F mice) further highlights the difference between the two distinct Th17 populations. SLP76 Y145F mice have increased numbers of nTh17 cells in the thymus compared to wild-type mice. However, peripheral naïve CD4+ T cells from these mice showed severely defective IL-17 production when cultured in vitro under conditions promoting Th17 cell differentiation. This defect was reflected in vivo as CD4+ T cells in the small intestinal lamina propria of SLP76 Y145F mice fail to produce IL-17. Using mixed radiation bone marrow chimeras, we found that the aberrant Th17 phenotype in the thymus and periphery of SLP76 Y145F mice is cell-intrinsic. Finally, adoptive transfer of purified nTh17 cells into RAG-deficient host mice revealed preferential homing of nTh17 cells to thymus and lung compared to other comparison/competitive populations that were co-transferred. Taken together, our data suggest a distinct population of Th17 cells that have characteristics of innate lymphocytes that function at the interface between innate and adaptive immunity. Understanding the biology of nTh17 cells will provide insight into the recently identified Th17 cells in human thymi and umbilical cord blood. Disclosures: No relevant conflicts of interest to declare.

Self-recognition is crucial for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment

Blood ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 270-277 ◽  
Author(s):  
Bruno Martin ◽  
Chantal Bécourt ◽  
Boris Bienvenu ◽  
Bruno Lucas
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Cell Pool ◽  
Self Recognition ◽  
Mhc Class Ii Molecules

The role of self-recognition in the maintenance of the peripheral CD4+ T-cell pool has been extensively studied, but no clear answer has so far emerged. Indeed, in studies of the role of self-major histocompatibility complex (MHC) molecules in CD4+ T-cell survival, several parameters must be taken into account when interpreting the results: (1) in a lymphopenic environment, observations are biased by concomitant proliferation of T cells arising in MHC-expressing mice; (2) the peripheral T-cell compartment is qualitatively and quantitatively different in nonlymphopenic, normal, and MHC class II-deficient mice; and (3) in C57BL/6 Aβ-/- mice (traditionally considered MHC class II-deficient), the Aα chain and the Eβ chain associate to form a hybrid AαEβ MHC class II molecule. In light of these considerations, we revisited the role of interactions with MHC class II molecules in the survival of peripheral CD4+ T cells. We found that the answer to the question “is self-recognition required for CD4+ T cells to survive?” is not a simple yes or no. Indeed, although long-term survival of CD4+ T cells does not depend on self-recognition in lymphopenic mice, interactions with MHC class II molecules are required for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment. (Blood. 2006;108:270-277)

scholarly journals MHC control of CD4+ T cell subset activation.

1989 ◽  
Vol 170 (6) ◽  
pp. 2135-2140 ◽  
Author(s):  
J S Murray ◽  
J Madri ◽  
J Tite ◽  
S R Carding ◽  
K Bottomly
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Cell Subset ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Selective Activation ◽  
Ifn Gamma

The present results demonstrate that CD4+ T cells activated in the primary in vivo response to antigen produce distinct patterns of cytokines depending upon the MHC class II haplotype of the responding mice. I-As mice were found to selectively activate IL-2/IFN-gamma-producing CD4+ T cells, whereas I-Ab mice exhibited selective activation of IL-4-producing CD4+ T cells in response to collagen IV. The effector response phenotype was found to correlate with the cytokine phenotype of CD4+ T cells activated in vivo; IL-2/IFN-gamma-producing cells giving rise to proliferative (cell-mediated) responses, IL-4-producing cells leading to secondary IgG (humoral) responses. Together the data support the notion that the outcome of a given immune response (e.g., protection vs. onset, tolerance vs. autoimmunity) may be determined in part by the type of CD4+ T cells initially activated by antigen. Moreover, the present experiments demonstrate for the first time that polymorphism in class II MHC can determine such selective activation of different cytokine-producing CD4+ T cell phenotypes.

scholarly journals CD4+ T-cell epitopes associated with antibody responses after intravenously and subcutaneously applied human FVIII in humanized hemophilic E17 HLA-DRB1*1501 mice

Blood ◽  
2012 ◽  
Vol 119 (17) ◽  
pp. 4073-4082 ◽  
Author(s):  
Katharina N. Steinitz ◽  
Pauline M. van Helden ◽  
Brigitte Binder ◽  
David C. Wraith ◽  
Sabine Unterthurner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Structural Features ◽  
Cd4 T Cell ◽  
T Cell Epitopes ◽  
Mhc Class Ii Molecules

Abstract Today it is generally accepted that B cells require cognate interactions with CD4+ T cells to develop high-affinity antibodies against proteins. CD4+ T cells recognize peptides (epitopes) presented by MHC class II molecules that are expressed on antigen-presenting cells. Structural features of both the MHC class II molecule and the peptide determine the specificity of CD4+ T cells that can bind to the MHC class II–peptide complex. We used a new humanized hemophilic mouse model to identify FVIII peptides presented by HLA-DRB1*1501. This model carries a knockout of all murine MHC class II molecules and expresses a chimeric murine-human MHC class II complex that contains the peptide-binding sites of the human HLA-DRB1*1501. When mice were treated with human FVIII, the proportion of mice that developed antibodies depended on the application route of FVIII and the activation state of the innate immune system. We identified 8 FVIII peptide regions that contained CD4+ T-cell epitopes presented by HLA-DRB1*1501 to CD4+ T cells during immune responses against FVIII. CD4+ T-cell responses after intravenous and subcutaneous application of FVIII involved the same immunodominant FVIII epitopes. Interestingly, most of the 8 peptide regions contained promiscuous epitopes that bound to several different HLA-DR proteins in in vitro binding assays.

510 Helping the killers: innovative cancer immunotherapy harnessing quasi-universal tumor antigen-specific CD4 T cells

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A546-A546
Author(s):  
Margaux Saillard ◽  
Amelie Cachot ◽  
Georg Alexander Rockinger ◽  
Philippe Guillaume ◽  
Julien Schmidt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Cells ◽  
Mhc Class Ii ◽  
Tumor Antigen ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Cell Clones ◽  
Mhc Class Ii Molecules

BackgroundWhile cancer immunotherapy has mainly focused on exploiting CD8 T cells given their role in the direct elimination of tumor cells, increasing evidence highlights the crucial roles played by CD4 T cells in anti-tumor immunity. However, their very low frequency, the lack of robust algorithms to predict peptide binding to MHC class II molecules and the high polymorphism of MHC class II molecules render the study and use of circulating tumor antigen-specific CD4 T cells challenging. In this regard, the HLA-DRB3*02:02 gene encoding an HLA allele that is expressed by half of the Caucasian population, offers a way to identify CD4 T cell-defined tumor antigens with broad cancer patient coverage.MethodsHere, we aim to identify, isolate and functionally characterize ‘quasi-universal’ human tumor antigen-specific HLA-DRB3*02:02-restricted CD4 T cells in cancer patients. Using an algorithm we recently developed in house,1 tumor-associated antigenic peptides binding to this allele are identified. We have generated a large collection of HLA-DRB3*02:02-restricted CD4 T cell clones of different tumor-antigen specificities. We will perform in vitro co-cultures of CD4 T cell clones with tumor cells to measure cytokine secretion, their tumor cell killing and their phenotypic profile (PD-1, TIM3, TIGIT, 4-1BB, CD40L, LAG3, VISTA, OX40). We will sequence and clone the TCR of the most promising candidates for adoptive cell transfer therapy. Lastly, we will directly evaluate the presence of these cells ex-vivo and longitudinally monitor them in patients.ResultsN/AConclusionsTogether, these results should contribute valuable targets for coordinated CD4 and CD8 T cell-based immunotherapy of cancer.ReferenceRacle, J., et al., Robust prediction of HLA class II epitopes by deep motif deconvolution of immunopeptidomes. Nat Biotechnol 2019. 37(11): p. 1283–1286.

scholarly journals Small amounts of superantigen, when presented on dendritic cells, are sufficient to initiate T cell responses.

1993 ◽  
Vol 178 (2) ◽  
pp. 633-642 ◽  
Author(s):  
N Bhardwaj ◽  
J W Young ◽  
A J Nisanian ◽  
J Baggers ◽  
R M Steinman
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Dendritic Cell ◽  
Mhc Class Ii ◽  
Cell Receptor ◽  
Class Ii ◽  
Cell Mediated Immunity ◽  
Quiescent T Cells ◽  
Antigen Presenting

Dendritic cells are potent antigen-presenting cells for several primary immune responses and therefore provide an opportunity for evaluating the amounts of cell-associated antigens that are required for inducing T cell-mediated immunity. Because dendritic cells express very high levels of major histocompatibility complex (MHC) class II products, it has been assumed that high levels of ligands bound to MHC products ("signal one") are needed to stimulate quiescent T cells. Here we describe quantitative aspects underlying the stimulation of human blood T cells by a bacterial superantigen, staphylococcal enterotoxin A (SEA). The advantages of superantigens for quantitative studies of signal one are that these ligands: (a) engage MHC class II and the T cell receptor but do not require processing; (b) are efficiently presented to large numbers of quiescent T cells; and (c) can be pulsed onto dendritic cells before their application to T cells. Thus one can relate amounts of dendritic cell-associated SEA to subsequent lymphocyte stimulation. Using radioiodinated SEA, we noted that dendritic cells can bind 30-200 times more superantigen than B cells and monocytes. Nevertheless, this high SEA binding does not underlie the strong potency of dendritic cells to present antigen to T cells. Dendritic cells can sensitize quiescent T cells, isolated using monoclonals to appropriate CD45R epitopes, after a pulse of SEA that occupies a maximum of 0.1% of surface MHC class II molecules. This corresponds to an average of 2,000 molecules per dendritic cell. At these low doses of bound SEA, monoclonal antibodies to CD3, CD4, and CD28 almost completely block T cell proliferation. In addition to suggesting new roles for MHC class II on dendritic cells, especially the capture and retention of ligands at low external concentrations, the data reveal that primary T cells can generate a response to exceptionally low levels of signal one as long as these are delivered on dendritic cells.

Induction and Break of Immune Tolerance to Human FVIII in a HLA-DRB1*1501 Humanized Hemophilic Mouse Model

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2280-2280
Author(s):  
Katharina Nora Steinitz ◽  
Brigitte Binder ◽  
Christian Lubich ◽  
Rafi Uddin Ahmad ◽  
Markus Weiller ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Mouse Model ◽  
Mhc Class Ii ◽  
Immune Tolerance ◽  
Cd4 T Cells ◽  
Hemophilia A ◽  
Class Ii ◽  
T Cell Epitopes

Abstract Abstract 2280 Development of neutralizing antibodies against FVIII is the major complication in the treatment of patients with hemophilia A. Although several genetic and environmental risk factors have been identified, it remains unclear why some patients develop antibodies while others do not. Understanding the underlying mechanisms that drive the decision of the immune system whether or not to make antibodies against FVIII would help to design novel therapeutics. We used a new humanized hemophilic mouse model that expresses the human MHC-class II molecule HLA-DRB1*1501 on the background of a complete knock out of all murine MHC-class II genes. Initial studies had indicated that only a fraction of these mice developed antibodies when intravenously (i.v.) treated with human FVIII. These findings which resemble the situation in patients with severe hemophilia A, evoked the question if the lack of antibody development in non-responder mice reflects the induction of specific immune tolerance after i.v. application of FVIII or represent non-responsiveness for other reasons. We addressed this question by choosing another application route (subcutaneous, s.c.) and by combining i.v. application with a concomitant activation of the innate immune system applying LPS, a well characterized ligand for toll-like receptor 4, together with FVIII. Both strategies resulted in the development of antibodies in all mice included in the study what suggested that non-responsiveness against i.v. FVIII does not reflect an inability to develop antibodies against FVIII. Next, we asked if i.v. FVIII does induce immune tolerance in non-responder mice. We pretreated mice with i.v. FVIII, selected non-responder mice and challenged them with s.c. FVIII. None of the mice developed antibodies what indicated that i.v. pretreatment had induced immune tolerance in non-responder mice. Currently, we test the hypothesis that immune tolerance after i.v. application is induced and maintained by FVIII-specific regulatory T cells. The differences in responder rates after i.v. and s.c. application of FVIII raised the question if there are differences in FVIII T-cell epitopes involved in the initial activation of FVIII-specific CD4+ T cells. We obtained spleen cells from mice treated with either i.v. or s.c. FVIII and generated CD4+ T-cell hybridoma libraries that were tested for peptide specificities. For this purpose we used a FVIII peptide library containing 15 mers with an offset of 3 amino acids. Our results indicate that the pattern of FVIII-specific T-cell epitopes involved in the activation of FVIII-specific CD4+ T cells after i.v. and s.c. application of FVIII is almost identical and represents a small set of FVIII peptides distributed over the A1, A2, B, A3 and C1 domains. Based on our results we conclude that the new HLA-DRB1*1501 hemophilic mouse model represents an interesting opportunity to uncover the mechanisms that drive the decision of the immune system whether or not to develop antibodies against FVIII. Disclosures: Steinitz: Baxter BioScience: Employment. Binder:Baxter BioScience: Employment. Lubich:Baxter BioScience: Employment. Ahmad:Baxter BioScience: Employment. Weiller:Baxter BioScience: Employment. de la Rosa:Baxter BioScience: Employment. Schwarz:Baxter BioScience: Employment. Scheiflinger:Baxter BioScience: Employment. Reipert:Baxter Innovations GmbH: Employment.

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