Project description:Tumors express a wide variety of both mutated and non-mutated antigens. Whether these tumor antigens are broadly recognized as âselfâ or âforeignâ by the immune system is currently unclear. Using an autochthonous prostate cancer model in which hemagglutinin (HA) is specifically expressed in the tumor (ProHA x TRAMP mice), as well as an analogous model wherein HA is expressed in normal tissues as a model self-antigen (C3HAHigh), we examined the transcriptional profile of CD4 T cells undergoing antigen-specific division. Consistent with our previous data, transfer of antigen-specific CD4 T cells into C3HAHigh resulted in a functionally inactivated CD4 T cell profile. Conversely, adoptive transfer of an identical CD4 T cell population into ProHA x TRAMP resulted in the induction of a regulatory phenotype (Treg) both at the transcriptional and functional level. Interestingly, this Treg skewing was a property of even early-stage tumors, suggesting Treg induction as an important tolerance mechanism during tumor development. The goal of this microarray is to detail the transcriptional profile differences between CD4 T cells that recognize their cognate antigen in the context of tumor (ProHA x TRAMP model) or self-antigen recognition (C3HA) or viral-antigen recognition (VaccHA) models or unprimed naïve state (Nontransgenic). The comparison contains both upregulated and downregulated transcripts. Experiment Overall Design: TCR transgenic CD4 T cells specific for hemagglutinin (HA) were adoptively transferred into tumor-antigen recognition model (ProHA x TRAMP), Self-antigen recognition model (C3HA), viral-antigen recognition model (VaccHA), and naïve control (Nontrangenic). Divided (CFSE diluted) CD4 T cells were sorted by FACS, RNA was extracted, and biological replicated were hybridized to an Affymetrix Mouse 430 Plus 2 expression array, followed by interrogation with an Affymetrix GeneChip Scanner 3000. RMA normalization was employed to identify differentially expressed transcripts.
Project description:Tumors express a wide variety of both mutated and non-mutated antigens. Whether these tumor antigens are broadly recognized as “self” or “foreign” by the immune system is currently unclear. Using an autochthonous prostate cancer model in which hemagglutinin (HA) is specifically expressed in the tumor (ProHA x TRAMP mice), as well as an analogous model wherein HA is expressed in normal tissues as a model self-antigen (C3HAHigh), we examined the transcriptional profile of CD4 T cells undergoing antigen-specific division. Consistent with our previous data, transfer of antigen-specific CD4 T cells into C3HAHigh resulted in a functionally inactivated CD4 T cell profile. Conversely, adoptive transfer of an identical CD4 T cell population into ProHA x TRAMP resulted in the induction of a regulatory phenotype (Treg) both at the transcriptional and functional level. Interestingly, this Treg skewing was a property of even early-stage tumors, suggesting Treg induction as an important tolerance mechanism during tumor development. The goal of this microarray is to detail the transcriptional profile differences between CD4 T cells that recognize their cognate antigen in the context of tumor (ProHA x TRAMP model) or self-antigen recognition (C3HA) or viral-antigen recognition (VaccHA) models or unprimed naïve state (Nontransgenic). The comparison contains both upregulated and downregulated transcripts. Keywords: Transcriptional Profile comparison, context dependent antigen recognition and T Cell differentiation
Project description:Tumor antigen-specific CD4+ T cells are required for the efficacy of immune checkpoint inhibitors in murine models but their contributions in human cancer are less understood. We used targeted single cell RNA sequencing and matching of T cell receptor sequences to identify signatures and functional correlates of tumor antigen-specific CD4+ T cells infiltrating human melanoma tumors. CD4+ T cells that recognize tumor-specific neoantigens express CXCL13 and are subdivided into clusters expressing memory and T follicular helper markers, and those expressing cytolytic markers, exhaustion markers and IFN-. In a cohort of melanoma patients, the frequency of CXCL13+ CD4+ T cells in the tumor correlated with the transcriptional states of CD8+ T cells and macrophages, maturation of B cells, and patient survival. Similar correlations were observed in a breast cancer cohort. These results identify distinct phenotypes and functional correlates of tumor antigen-specific CD4+ T cells in melanoma and suggest the possibility of using such cells to modify the tumor microenvironment.
Project description:The immune system must be able to distinguish self from non-self. During pregnancy, the mother’s immune system does not recognize the placenta as foreign because proteins expressed by tropbholasts, the placental cells that interface with the maternal immune system, do not activate maternal T cells. These activation defects have been previously attributed to suppression by regulatory T cells, while mechanisms of maternal B cell tolerance to trophoblast antigens have not been identified. In this study, we provide evidence that glycan-mediated B cell suppression plays a key role in establishing fetomaternal tolerance in mice. We find that trophoblast antigen-specific B cells are profoundly suppressed via CD22/LYN inhibitory signaling, in turn implicating the antigens’ sialic acids as key suppressive determinants. We also find that B cells mediate the antigen’s MHCII-restricted presentation to CD4 T cells, leading to T cell suppression. The specific goal of the mass spectrometry undertaking deposited here was to identify sialylated “true” placental-derived proteins present in the human and mouse serum proteome during pregnancy. Overall, our findings reveal protein glycosylation as a fundamental feature of placental “self-recognition” and may have relevance to pregnancy complications and tumor immune evasion. Furthermore, we anticipate these findings will enhance synthetic efforts to harness glycans to control antigen-specific immune responses in the treatment of autoimmune diseases.
Project description:CD4 T follicular helper (Tfh) cells provide the required signals to B cells for germinal center reactions that are necessary for longlived antibody responses. However, it remains unclear whether there are CD4+ memory T cells committed to the Tfh lineage after antigen clearance. Using adoptive transfer of antigen-specific memory CD4+ subpopulations (based on CXCR5 and Ly6c expression)in the LCMV infection model, we found that there are distinct memory CD4+ T cell populations with commitment to the Tfh and Th1 lineages. Our conclusions are based on gene expression profiles, epigenetic studies and phenotypic and functional analysis. The gene expression profiles of virus-specific CD4 T cell subets at effector and memory stages is presented here. The SMARTA TCR transgenic / adptive transfer system was used to identify and sort subsets of antigen-specific CD4 T cells (based on their expression of Ly6c and CXCR5) elicited after acute infection with LCMV (Arm).
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and mRNA vaccination induce robust CD4+ T cell responses. Using single-cell transcriptomics, here, we evaluated CD4+ T cells specific for the SARS-CoV-2 spike protein in the blood and draining lymph nodes (dLNs) of individuals 3 months and 6 months after vaccination with the BNT162b2 mRNA vaccine. We analyzed 1,277 spike-specific CD4+ T cells, including 238 defined using Trex, a deep learning-based reverse epitope mapping method to predict antigen specificity. Human dLN spike-specific CD4+ follicular helper T (TFH) cells exhibited heterogeneous phenotypes, including germinal center CD4+ TFH cells and CD4+IL-10+ TFH cells. Analysis of an independent cohort of SARS-CoV-2-infected individuals 3 months and 6 months after infection found spike-specific CD4+ T cell profiles in blood that were distinct from those detected in blood 3 months and 6 months after BNT162b2 vaccination. Our findings provide an atlas of human spike-specific CD4+ T cell transcriptional phenotypes in the dLNs and blood following SARS-CoV-2 vaccination or infection.
Project description:Despite antiretroviral therapy (ART), HIV-1 persists in latently-infected CD4+ T cells, preventing cure. Antigen (Ag) drives proliferation of infected cells, preventing latent reservoir decay. However, the relationship between antigen recognition and HIV-1 gene expression is poorly understood since most studies of latency reversal use agents that induce non-specific global T cell activation. Here, we isolated rare CD4+ T cells responding to cytomegalovirus (CMV) or HIV-1 Gag antigens from participants on long-term ART and assessed T cell activation and HIV-1 RNA expression upon co-culture with autologous dendritic cells (DCs) presenting cognate antigens. Physiological presentation of cognate antigens induced broad T cell activation (median 42-fold increase in CD154+CD69+ cells) and significantly increased HIV-1 transcription (median 4-fold), mostly through the induction of rare cells with higher viral expression. Thus, despite low proviral inducibility, physiologic antigen recognition can promote HIV-1 expression, potentially contributing to spontaneous reservoir activity on ART and viral rebound upon ART interruption. Additionally, we observed striking differences in the transcriptome profiles of Ag-responding CD4+ T cells after stimulations with Ag or global T cell activators. This analysis revealed quantitative differences between NFAT and NFkB target genes and may guide future approaches to Ag-mediated HIV-1 latency reversal.
Project description:CD4+ T cell activation by recognition of Human Leukocyte Antigen II (HLAII)-presented peptides is a key step in the development of unwanted immunogenicity against biotherapeutics
Project description:The gut epithelium is populated by intraepithelial lymphocytes (IELs), a heterogeneous T cell population with cytotoxic and regulatory properties, which can be imprinted on CD4+ T cells at the epithelium. However, the role of the T cell receptor (TCR) in this process remains unclear. Single-cell transcriptomic analyses revealed distinct clonal expansions between cell states, with CD4-IELs being one of the least diverse populations. Conditional deletion of TCR on differentiating CD4+ T cells or of MHCII on intestinal epithelial cells prevented CD4-IEL differentiation. However, TCR ablation on differentiated CD4-IELs, or long-term cognate antigen withdraw, did not affect their maintenance. TCR re-engaging of antigen-specific CD4-IELs during Listeria monocytogenes infection did not alter their state but correlated with reduced bacteria invasion. Thus, local antigen recognition is an essential signal for differentiation of T cells at the epithelium but differentiated CD4-IELs are able to preserve an effector program in the absence of TCR signaling.