Project description:To identify unique chromatin regions predicting the anti-tumor efficacy of Nrf2-deleted smart CD8+ T cell therapy, we performed an assay for transposase-accessible chromatin sequencing (ATAC-seq) using tumor-infiltrating CD8+ T cells from tumor-bearing mice transferred Nrf2-deficient CD8+ T cells. From the analysis of ATAC-seq data, we identified quantitatively distinct open regions of chromatin that distinguish Nrf2-deficient CD8+ T cells or WT CD8+ T cells.
Project description:The regulatory circuits dictating CD8+ T cell responsiveness vs. exhaustion during anti-tumor immunity are incompletely understood. Here, we report that tumor-infiltrating antigen-specific PD-1+ TCF-1- CD8+ T cells express the immunosuppressive cytokine Fgl2. Conditional deletion of Fgl2 from antigen-specific CD8+ T cells prolonged CD8+ T cell persistence, decreased phenotypic and transcriptomic signatures of T cell exhaustion, and improved tumor control. Melanoma patients who died of their disease exhibited increased expression of Fgl2 in tumor-infiltrating CD8+ T cells as compared to those who survived. PD-1+CD8+ T cell-derived Fgl2 also negatively regulated virus-specific T cell responses in a model of chronic viral infection. Mechanistically, the enhanced responsiveness of Fgl2-deficient CD8+ T cells is underpinned by the interaction of Fgl2 with CD8+ T cell-expressed FcγRIIB, ligation of which results in caspase 3/7-mediated apoptosis. These data illuminate a novel cell-autonomous regulatory axis by which PD-1+ CD8+ T cell responses are regulated in vivo.
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:In patients with pancreatic ductal adenocarcinoma (PDAC), we show that response to radiation therapy (RT) is characterized by increased IL2R and IL2R expression, decreased ILR2 and exhaustion markers. The bispecific PD-1-targeted IL-2 variant (IL2v) immunocytokine with engineered IL-2 cis-targeted to PD-1 and abolished IL2R binding targets the activation of tumor-antigen specific T cells while rescuing them from Treg suppression. Using aPD1-IL2v in orthotopic PDAC KPC-driven tumor models, we show marked improvement in local and metastatic survival along with profound increase in tumor-infiltrating polyfunctional CD8 T cell subsets with a transcriptionally and metabolically active phenotype, and preferential activation of antigen-specific CD8 T cells. In combination with single dose RT, aPD1-IL2v treatment results in a robust, durable expansion of polyfunctional CD8 T cells, T cell stemness, tumor-specific memory immune response, NK cell activation, and decreased Tregs. These data show that the novel aPD1-IL2v, leads to profound local and distant response in PDAC.
Project description:During persistent antigen stimulation, CD8+ cytolytic T cells (CTL) show a gradual decrease in effector function, or “exhaustion”, which impairs the immune response to tumors and infections. Here we show that NFAT, a transcription factor with an established role in T cell activation, in parallel controls a second transcriptional program conferring the characteristic features of CD8+ T cell exhaustion, including upregulation of genes encoding inhibitory cell surface receptors and diminished TCR signaling. Expression of an engineered NFAT1, which induces this negative regulatory program in the absence of the effector program, interferes with the ability of CD8+ T cells to protect against Listeria infection or attenuate tumor growth in vivo. NFAT elicits this second program of gene expression in large part by binding to a subset of the sites occupied by NFAT during a typical effector response, suggesting that a balance between the two pathways determines the outcome of TCR signaling. Determination of NFAT1 binding sites in CD8 T cells in vitro
Project description:T cell exhaustion is a progressive loss of effector function and memory potential due to persistent antigen exposure, which occurs in chronic viral infections and cancer. Here we investigate the relation between gene expression and chromatin accessibility in CD8+ tumor-infiltrating lymphocytes (TIL) that recognize a model tumor antigen and have features of both activation and functional exhaustion. By filtering out accessible regions observed in bystander, non-exhausted, TIL and in acutely restimulated CD8+ T cells, we define a pattern of chromatin accessibility specific for T cell exhaustion, characterized by enrichment for consensus binding motifs for Nr4a and NFAT transcription factors. Anti-PD-L1 treatment of tumor-bearing mice results in cessation of tumor growth and partial rescue of cytokine production by the dysfunctional TIL, with only limited changes in gene expression and chromatin accessibility. Our studies provide a valuable resource for the molecular understanding of T cell exhaustion in cancer and other inflammatory settings.