Project description:Single cell ATAC sequencing of SIINFEKL-reactive immune cell from intracranial murine GL261-SIINFEKL tumors 20 days after inoculation. SIINFEKL-reactive T cells were sorted based on dextramer staining. We show that loss of major histocompatibility complex (MHC) class II (MHCII)-restricted antigen presentation on bbm drives dysfunctional intratumoral tumor-reactive CD8+ T cell states through increased chromatin accessibility and expression of Tox, a critical regulator of T cell exhaustion.
Project description:Dendritic cells (DCs) process and present self and foreign antigens to induce tolerance or immunity. In vitro models suggest that induction of immunity is controlled by regulating the presentation of antigen, but little is known about how DCs control antigen presentation in vivo. To examine antigen processing and presentation in vivo we specifically targeted antigens to the two major subsets of DCs using chimeric monoclonal antibodies. Unlike CD8+ DCs that express the cell surface protein CD205, CD8- DCs, which are positive for the 33D1 antigen, are specialized for presentation on MHC class II. This difference in antigen processing is intrinsic to the DC subsets and associated with increased expression of proteins associated with MHC processing. Experiment Overall Design: This study includes data from cell sort purified dendritic cells, B cells and CD4 and CD8 T cells. The genearray was performed to identify the transmembrane molecule recognized by the antibody 33D1. The antibody 33D1 binds specifically to CD8-CD11cHigh DCs in the spleen. Therfore the data set was reduced in this way that all molecules that are expressed either in CD8=CD11cHigh DCs, B cells and T cells were diminished of the CD8+CD11cHigh DC data set. This Genearray was also used to analyze MHC class I and MHC class II associated moelcules as the DC subsets differ in the antigen presentation. Each Series consists of 3 individuall samples
Project description:Major Histocompatibility Complex Class II antigen presentation underlies a wide range of immune responses in health and disease. Although peptide ligand binding affinity has been the major focus for explaining and predicting class II antigens, we know that the levels and activities of accessory molecules, HLA-DM (DM) and HLA-DO (DO) can have strong effects on peptide repertoires. However, the extent to which these antagonistic proteins’ levels relative to one another shape the identities and properties of peptides selected for presentation remains unclear. Hence, after creating cell line panel with varying DO:DM ratios, of we set out to measure the effects these ratios can have on peptide presentation. Using a combined immunopeptidomic and proteomic discovery strategy, we profiled ligandome differences across this panel. By surveying over 10,000 unique HLA-DR4-presented peptides, we found marked increases in repertoire diversity and altered physical properties of presented peptides that corresponded with increasing DO:DM ratios.
Project description:Major Histocompatibility Complex of Class II (MHCII) antigen presentation is a key event of adaptive immunity. HLA-DM favors the presentation of kinetically stable peptide-MHCII complexes but does not bind peptides itself and exhibits only a low degree of polymorphism. To date, no evidence for altered function of DM due to natural variations has been reported. We define the presence of DM haplotypes in human populations covered by the 1000 Genomes Project and probe their activity in antigen presentation assays. Our results indicate a clear linkage between DMA*0103 and DMB*0107 never reported before. Thehe corresponding heterodimer features a distinct activity profile when compared to the most frequent allotype (DMA*0101-DMB*0101). In vitro experiments demonstrate a broader pH activity profile for the new allotype, explaining its characteristic cellular function. Together, our results suggest that natural variations of DM have important consequences for an individual’s adaptive immune response.
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
Project description:In contrast to adult mammals, adult zebrafish are able to fully regenerate injured cardiac tissue, and this regeneration process requires an adequate and tightly controlled immune response. However, which immune aspects drive particular aspects of the regenerative response are unclear. Here, we report the participation and requirement of the antigen presentation-adaptive immunity axis during zebrafish cardiac regeneration. We found that, in addition to immune cells, endocardial cells start expressing antigen presentation genes following the initial innate immune response. Consistent with this finding, we observed that helper T cells, a.k.a. Cd4+ T cells, are closely associated with phosphoERK+ (pERK+) (i.e., activated) endocardial cells at these stages. We inactivated major histocompatibility complex (MHC) class II antigen presentation by generating cd74a; cd74b double mutants, which display a defective immune response. In these mutants, both Cd4+ T cells and pERK+ endocardial cells fail to efficiently infiltrate the injured tissue. Notably, this model of compromised antigen presentation exhibits additional defects in cardiac regeneration including reduced cardiomyocyte dedifferentiation and proliferation. Altogether, these findings reveal a necessary role for antigen presentation during zebrafish cardiac regeneration and point to an immune crosstalk between T cells and endocardial cells, thereby further establishing a link between the adaptive immune response and tissue regeneration.
Project description:Dendritic cells (DCs) process and present self and foreign antigens to induce tolerance or immunity. In vitro models suggest that induction of immunity is controlled by regulating the presentation of antigen, but little is known about how DCs control antigen presentation in vivo. To examine antigen processing and presentation in vivo we specifically targeted antigens to the two major subsets of DCs using chimeric monoclonal antibodies. Unlike CD8+ DCs that express the cell surface protein CD205, CD8- DCs, which are positive for the 33D1 antigen, are specialized for presentation on MHC class II. This difference in antigen processing is intrinsic to the DC subsets and associated with increased expression of proteins associated with MHC processing. Keywords: cell type comparison of wildtype and Flt3L melonom spleen DCs and splenic B cells, CD4 and CD8 T cells