scholarly journals Ligation of MHC Class II Induces PKC-Dependent Clathrin-Mediated Endocytosis of MHC Class II

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1810
Author(s):  
Kento Masaki ◽  
Yuhji Hiraki ◽  
Hiroka Onishi ◽  
Yuka Satoh ◽  
Paul A. Roche ◽  
...  

In addition to antigen presentation to CD4+ T cells, aggregation of cell surface major histocompatibility complex class II (MHC-II) molecules induces signal transduction in antigen presenting cells that regulate cellular functions. We previously reported that crosslinking of MHC-II induced the endocytosis of MHC-II, which was associated with decreased surface expression levels in murine dendritic cells (DCs) and resulted in impaired activation of CD4+ T cells. However, the downstream signal that induces MHC-II endocytosis remains to be elucidated. In this study, we found that the crosslinking of MHC-II induced intracellular Ca2+ mobilization, which was necessary for crosslinking-induced MHC-II endocytosis. We also found that these events were suppressed by inhibitors of Syk and phospholipase C (PLC). Treatments with a phorbol ester promoted MHC-II endocytosis, whereas inhibitors of protein kinase C (PKC) suppressed crosslinking-induced endocytosis of MHC-II. These results suggest that PKC could be involved in this process. Furthermore, crosslinking-induced MHC-II endocytosis was suppressed by inhibitors of clathrin-dependent endocytosis. Our results indicate that the crosslinking of MHC-II could stimulate Ca2+ mobilization and induce the clathrin-dependent endocytosis of MHC-II in murine DCs.

1998 ◽  
Vol 187 (5) ◽  
pp. 693-702 ◽  
Author(s):  
Ferry Ossendorp ◽  
Erica Mengedé ◽  
Marcel Camps ◽  
Rian Filius ◽  
Cornelis J.M. Melief

This study shows that induction of tumor-specific CD4+ T cells by vaccination with a specific viral T helper epitope, contained within a synthetic peptide, results in protective immunity against major histocompatibility complex (MHC) class II negative, virus-induced tumor cells. Protection was also induced against sarcoma induction by acutely transforming retrovirus. In contrast, no protective immunity was induced by vaccination with an unrelated T helper epitope. By cytokine pattern analysis, the induced CD4+ T cells were of the T helper cell 1 type. The peptide-specific CD4+ T cells did not directly recognize the tumor cells, indicating involvement of cross-priming by tumor-associated antigen-presenting cells. The main effector cells responsible for tumor eradication were identified as CD8+ cytotoxic T cells that were found to recognize a recently described immunodominant viral gag-encoded cytotoxic T lymphocyte (CTL) epitope, which is unrelated to the viral env-encoded T helper peptide sequence. Simultaneous vaccination with the tumor-specific T helper and CTL epitopes resulted in strong synergistic protection. These results indicate the crucial role of T helper cells for optimal induction of protective immunity against MHC class II negative tumor cells. Protection is dependent on tumor-specific CTLs in this model system and requires cross-priming of tumor antigens by specialized antigen-presenting cells. Thus, tumor-specific T helper epitopes have to be included in the design of epitope-based vaccines.


2022 ◽  
Author(s):  
Emily M Eshleman ◽  
Tzu-Yu Shao ◽  
Vivienne Woo ◽  
Taylor Rice ◽  
Jordan Whitt ◽  
...  

Dysregulated immune responses to resident microbes promote pathologic inflammation, however, the mechanisms instructing commensal-specific T cells remain poorly understood. Here, we find that non-hematopoietic intestinal epithelial cells (IECs) represent the primary cells expressing major histocompatibility complex (MHC) II at the intestinal host-microbiota interface. Interestingly, epithelial MHCII and commensal-specific CD4+ T cells were concurrently induced by post-natal microbiota colonization, provoking the hypothesis that epithelial MHCII regulates local commensal-specific CD4+ T cells. While MHCII on classical antigen presenting cells directs expansion of antigen-specific CD4+ T cells, loss of IEC-intrinsic MHCII surprisingly led to elevated commensal-specific CD4+ T cells in the intestine. Further, epithelial MHCII expression actively limited accumulation of antigen-specific CD4+ T cells in adult mice. Expansion of commensal-specific Th17 cells was restricted by epithelial MHCII, and remarkably mice lacking epithelial MHCII were highly susceptible to microbiota-triggered inflammation. Collectively, these data indicate that impaired epithelial MHCII-T cell regulation within mucosal tissues alters microbiota-specific immunity and predisposes to chronic inflammation.


1992 ◽  
Vol 176 (1) ◽  
pp. 275-280 ◽  
Author(s):  
M A Blackman ◽  
F E Lund ◽  
S Surman ◽  
R B Corley ◽  
D L Woodland

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.


1996 ◽  
Vol 184 (5) ◽  
pp. 1747-1753 ◽  
Author(s):  
J F Katz ◽  
C Stebbins ◽  
E Appella ◽  
A J Sant

We have studied the consequences of invariant chain (Ii) and DM expression on major histocompatibility complex (MHC) class II function. Ii has a number of discrete functions in the biology of class II, including competitive blocking of peptide binding in the endoplasmic reticulum and enhancing localization in the endocytic compartments. DM is thought to act primarily in endosomes to promote dissociation of the Ii-derived (CLIP) peptide from the class II antigen-binding pocket and subsequent peptide loading. In this study, we have evaluated the functional role of Ii and DM by examining their impact on surface expression of epitopes recognized by a large panel of alloreactive T cells. We find most epitopes studied are influenced by both Ii and DM. Most strikingly, we find that surface expression of a significant fraction of peptide-class II complexes is extinguished, rather than enhanced, by DM expression within the APC. The epitopes antagonized by DM do not appear to be specific for CLIP. Finally, we found that DM was also able to extinguish recognition of a defined peptide derived from the internally synthesized H-2Ld protein. Thus, rather than primarily serving in the removal of CLIP, DM may have a more generalized function of editing the array of peptides that are presented by class II. This editing can be either positive or negative, suggesting that DM plays a specifying role in the display of peptides presented to CD4 T cells.


1993 ◽  
Vol 178 (2) ◽  
pp. 589-596 ◽  
Author(s):  
T M Laufer ◽  
M G von Herrath ◽  
M J Grusby ◽  
M B Oldstone ◽  
L H Glimcher

Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease marked by hyperglycemia and mononuclear cell infiltration of insulin-producing beta islet cells. Predisposition to IDDM in humans has been linked to the class II major histocompatibility complex (MHC), and islet cells often become aberrantly class II positive during the course of the disease. We have used two recently described transgenic lines to investigate the role of class II molecules and CD4+ T cells in the onset of autoimmune insulitis. Mice that are class II deficient secondary to a targeted disruption of the A beta b gene were bred to mice carrying a transgene for the lymphocytic choriomenigitis virus (LCMV) glycoprotein (GP) targeted to the endocrine pancreas. Our results indicate that class II-deficient animals with and without the GP transgene produce a normal cytotoxic T lymphocyte response to whole LCMV. After infection with LCMV, GP-transgenic class II-deficient animals develop hyperglycemia as rapidly as their class II-positive littermates. Histologic examination of tissue sections from GP-transgenic class II-deficient animals reveals lymphocytic infiltrates of the pancreatic islets that are distinguishable from those of their class II-positive littermates only by the absence of infiltrating CD4+ T cells. These results suggest that in this model of autoimmune diabetes, CD4+ T cells and MHC class II molecules are not required for the development of disease.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 196-196
Author(s):  
Nicoletta Sorvillo ◽  
Simon D van Haren ◽  
Wouter Pos ◽  
Eszter Herczenik ◽  
Rob Fijnheer ◽  
...  

Abstract Abstract 196 ADAMTS13 is a plasma metalloproteinase that regulates platelet adhesion and aggregation by virtue of its ability to process newly released ultra-large von Willebrand factor (VWF) multimers on the surface of endothelial cells. Autoantibodies directed against ADAMTS13 prohibit the processing of VWF multimers initiating a rare and life-threatening disorder called acquired thrombotic thrombocytopenic purpura (TTP). HLA-DRB1*11 has recently been identified as a risk factor for acquired TTP. This finding implies that formation of autoantibodies towards ADAMTS13 depends on appropriate presentation of ADAMTS13 derived peptides to CD4+ T-cells by antigen presenting cells. Here, we investigate endocytosis of recombinant ADAMTS13 by immature monocyte-derived dendritic cells (iDCs) using flow cytometry and confocal microscopy. Upon incubation of fluorescently labeled-rADAMTS13 with DCs, a time- and concentration dependent uptake of ADAMTS13 was observed. Endocytosis of ADAMTS13 was completely blocked upon addition of EGTA and mannan. We subsequently explored involvement of C-type lectins (CLRs) in the uptake of ADAMTS13 using specific blocking antibodies and siRNA silencing. We found that ADAMTS13 endocytosis was significantly decreased in cells treated with a monoclonal antibody directed towards macrophage mannose receptor (MR). Furthermore siRNA silencing of MR reduced the uptake of ADAMTS13 by dendritic cells. In vitro binding studies revealed that ADAMTS13 interacts with the carbohydrate recognition domains of MR. These data show that ADAMTS13 is internalized by iDCs in a MR-dependent manner. Antigen presenting cells continuously process endogenous and exogenous antigens into small peptides that are loaded on MHC class I or MHC class II for presentation to T lymphocytes. We have recently developed a method to analyze HLA-DR-presented peptide repertoires of dendritic cells pulsed with antigen (van Haren et al., 2011). Here, we addressed which ADAMTS13-derived peptides were presented on MHC class II alleles of a panel of both HLA-DRB1*11 positive and negative donors. Compared to previous studies with model antigens only a limited number of ADAMTS13-derived peptides were presented on MHC class II. Inspection of peptide-profiles obtained from DRB1*11 positive individuals revealed that two antigenic “core” peptides derived from the CUB1-2 domains of ADAMTS13 were presented by a DR11-positive donor. In addition to these immuno-dominant peptides several other peptides were also presented although with a markedly reduced efficiency. Our findings show that DRB1*11 expressing antigen presenting cells preferentially present antigenic “core” peptides derived from the CUB1-2 domains of ADAMTS13. We hypothesize that functional presentation of these peptides on HLA-DRB1*11 contributes to the onset of acquired TTP by stimulating low affinity self-reactive CD4+ T cells that have escaped negative selection in the thymus. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2147-2147
Author(s):  
Caisheng Lu ◽  
Huihui Ma ◽  
Liangsong Song ◽  
Shirong Li ◽  
Suzanne Lentzsch ◽  
...  

Abstract IFNγ signaling plays a critical role in the pathogenesis of GVHD. In this study, we observed that LPS-maturated bone marrow-derived dendritic cells (BMDCs) lacking IFNγ receptor (IFNγR, GRKO) or signal transducer and activator of transcription 1 (STAT1KO) had increased expression of major histocompatibility complex class II (MHC II), CD86, CD80, and enhanced allo-stimulatory capacity. This was further confirmed using fully MHC-mismatched bone marrow transplantation (BMT) studies. APC of GRKO or STAT1KO recipients had increased MHC II expression, which was associated with enhanced activation and expansion of donor CD4 and CD8 T cells and subsequently accelerated GVHD mortality compared to wild type (WT) controls. This increased GVHD mortality and increased MHC II expression on host APCs was further observed in the absence of recipient conditioning in the B6→CB6F1 mouse model. This was associated with increased presentation of host derived endogenous Eα52-68 peptide via I-Ab on recipient CD11c+ cells as detected by staining with the YA-e antibody. Furthermore, we could demonstrate that absence of IFNγR in BMDC promotes presentation Eα52-68 peptide and subsequently elicits pronounced activation, expansion and Th1 differentiation of TEa-TCR-tg CD4 T cells which recognize the Eα52-68 peptide presented by I-Ab. Next, we assessed the impact of this pathway on presentation of exogenous antigens. Interestingly, when lysate prepared from BALB/c splenocytes was incubated with BMDCs from B6 mice, Y-Ae expression on STAT1-/- BMDCs was significantly reduced compared to wild type BMDCs allowing us to hypothesize that IFNγ/STAT1 signaling may play an important role in promoting presentation of exogenous antigen while suppressing presentation of endogenous antigen. To further confirm this hypothesis, we used ovalbumin (OVA) as a second model antigen. To assess the impact of IFNγ/STAT1 signaling on presentation of exogenous antigen, WT, GRKO or STAT1KO BMDC were directly pulsed with OVA. To address the role in endogenous antigen presentation we studied act-mOVA-transgenic wildtype, act-mOVA.GRKO or act-mOVA.STAT1KO BMDCs. Transgenic OT-II CD4 T cells express a TCR specific for the OVA peptide 323-33 presented by I-Ab. The proliferation/activation of OT II T cells was monitored by flow cytometer as readout for effective Ag presentation. Our data demonstrated that IFNγR- or STAT1-deficient BMDCs loaded with exogenous intact OVA protein were compromised in promoting OT II proliferation. In contrast, responder OT-II CD4 T cells proliferated much more vigorously when stimulated with IFNγR/STAT1-deficient m-Act-OVA BMDCs compared to controls. We further observed significantly impaired OT-II cell proliferation in IFNγR or STAT1-deficient mice immunized with OVA indicating impaired presentation of exogenous antigens. However, OT-II CD4 T cells injected into lethally irradiated act-mOVA.STAT1KO transgenic mice proliferated more robustly and displayed increased Th1 differentiation compared to control mice when tested 3 days after OT II administration. We next started to assess several key factors (Ii [invariant chain, CD74], Cathepsin S [CTSS], H2-M, CIITA and MARCH1), known to be involved in the process of MHC class II antigen presentation and MHC II expression. We found retention of Invariant chain (CD74) expression as well as reduced CTSS and H2M expression in GRKO or STAT1KO BMDC following LPS-maturation. Furthermore, we observed significantly reduced lysosome formation/function in STAT1KO BMDCs compared to wild type BMDCs after LPS maturation. These data suggest that exogenous protein-derived peptide exchange in the MHCII compartment (MIIC) is impaired in STAT1KO BMDCs. Immature and LPS-maturated STAT1-/-BMDCs had significantly increased autophagy, which could explain enhanced endogenous Ag presentation since autophagy has been demonstrated to be critical in MHC II Ag presentation of cytoplasmic constituents. Finally, we found evidence of enhanced MHC II synthesis as supported by increased CIITA mRNA expression and conversely reduced MHC II degradation as indicated by reduced MARCH1 expression. In summary our data suggest that absence of IFNγR/STAT1 signaling in DC leads to abnormal surface MHC II turnover, promotes presentation of endogenous peptides and concomitantly impairs processing and presentation of exogenous antigens. Disclosures Lentzsch: BMS: Consultancy; Foundation One: Consultancy; Celgene: Consultancy, Honoraria.


1998 ◽  
Vol 187 (11) ◽  
pp. 1871-1883 ◽  
Author(s):  
Laurent Gapin ◽  
Yoshinori Fukui ◽  
Jean Kanellopoulos ◽  
Tetsuro Sano ◽  
Armanda Casrouge ◽  
...  

The positive selection of CD4+ T cells requires the expression of major histocompatibility complex (MHC) class II molecules in the thymus, but the role of self-peptides complexed to class II molecules is still a matter of debate. Recently, it was observed that transgenic mice expressing a single peptide–MHC class II complex positively select significant numbers of diverse CD4+ T cells in the thymus. However, the number of selected T cell specificities has not been evaluated so far. Here, we have sequenced 700 junctional complementarity determining regions 3 (CDR3) from T cell receptors (TCRs) carrying Vβ11-Jβ1.1 or Vβ12-Jβ1.1 rearrangements. We found that a single peptide–MHC class II complex positively selects at least 105 different Vβ rearrangements. Our data yield a first evaluation of the size of the T cell repertoire. In addition, they provide evidence that the single Eα52-68–I-Ab complex skews the amino acid frequency in the TCR CDR3 loop of positively selected T cells. A detailed analysis of CDR3 sequences indicates that a fraction of the β chain repertoire bears the imprint of the selecting self-peptide.


2001 ◽  
Vol 194 (4) ◽  
pp. 427-438 ◽  
Author(s):  
Steven J. Bensinger ◽  
Antonio Bandeira ◽  
Martha S. Jordan ◽  
Andrew J. Caton ◽  
Terri M. Laufer

CD4+25+ T cells are a unique population of immunoregulatory T cells which are critical for the prevention of autoimmunity. To address the thymic selection of these cells we have used two models of attenuated thymic deletion. In K14-Aβb mice, major histocompatibility complex (MHC) class II I-Ab expression is limited to thymic cortical epithelium and deletion by hematopoietic antigen-presenting cells does not occur. In H2-DMα–deficient mice, MHC class II molecules contain a limited array of self-peptides resulting in inefficient clonal deletion. We find that CD4+25+ T cells are present in the thymus and periphery of K14-Aβb and H2-DMα–deficient mice and, like their wild-type counterparts, suppress the proliferation of cocultured CD4+25− effector T cells. In contrast, CD4+25+ T cells from MHC class II–deficient mice do not suppress responder CD4+ T cells in vitro or in vivo. Thus, development of regulatory CD4+25+ T cells is dependent on MHC class II-positive thymic cortical epithelium. Furthermore, analysis of the specificities of CD4+25+ T cells in K14-Aβb and H2-DMα–deficient mice suggests that a subset of CD4+25+ T cells is subject to negative selection on hematopoietic antigen-presenting cells.


1997 ◽  
Vol 186 (8) ◽  
pp. 1223-1232 ◽  
Author(s):  
Thomas Brocker

Thymic T cell development is controlled by T cell receptor (TCR)–major histocompatibility complex (MHC) interactions, whereas a further dependence of peripheral mature T cells on TCR–MHC contact has not been described so far. To study this question, CD4 T cell survival was surveyed in mice lacking MHC class II expression and in mice expressing MHC class II exclusively on dendritic cells. Since neither of these mice positively select CD4 T cells in the thymus, they were grafted with MHC class II–positive embryonic thymic tissue, which had been depleted of bone marrow derived cells. Although the thymus grafts in both hosts were repopulated with host origin thymocytes of identical phenotype and numbers, an accumulation of CD4+ T cells in peripheral lymphoid organs could only be observed in mice expressing MHC class II on dendritic cells, but not in mice that were completely MHC class II deficient. As assessed by histology, the accumulating peripheral CD4 T cells were found to be in close contact with MHC class II+ dendritic cells, suggesting that CD4 T cells need peripheral MHC class II expression for survival and that class II+ dendritic cells might play an important role for the longevity of CD4 T cells.


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