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: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:T cell exhaustion is a major impediment to anti-tumor immunity. However, it remains elusive how other immune cells in the tumor microenvironment (TME) contribute to this dysfunctional state. Here we show that the biology of tumor-associated macrophages (TAM) and exhausted T cells (Tex) in the TME is extensively linked. We demonstrate that in vivo depletion of TAM reduces exhaustion programs in tumor-infiltrating CD8+ T cells and reinvigorates their effector potential. Reciprocally, transcriptional and epigenetic profiling reveals that Tex express factors that actively recruit monocytes to the TME and shape their differentiation. Using lattice light sheet microscopy, we show that TAM and CD8+ T cells engage in unique long-lasting antigen-specific synaptic interactions that fail to activate T cells, but prime them for exhaustion, which is then accelerated in hypoxic conditions. Spatially resolved sequencing supports a spatiotemporal self-enforcing positive feedback circuit that is aligned to protect rather than destroy a tumor.
Project description:T cell exhaustion is a major impediment to anti-tumor immunity. However, it remains elusive how other immune cells in the tumor microenvironment (TME) contribute to this dysfunctional state. Here we show that the biology of tumor-associated macrophages (TAM) and exhausted T cells (Tex) in the TME is extensively linked. We demonstrate that in vivo depletion of TAM reduces exhaustion programs in tumor-infiltrating CD8+ T cells and reinvigorates their effector potential. Reciprocally, transcriptional and epigenetic profiling reveals that Tex express factors that actively recruit monocytes to the TME and shape their differentiation. Using lattice light sheet microscopy, we show that TAM and CD8+ T cells engage in unique long-lasting antigen-specific synaptic interactions that fail to activate T cells, but prime them for exhaustion, which is then accelerated in hypoxic conditions. Spatially resolved sequencing supports a spatiotemporal self-enforcing positive feedback circuit that is aligned to protect rather than destroy a tumor.
Project description:T cell exhaustion is a major impediment to anti-tumor immunity. However, it remains elusive how other immune cells in the tumor microenvironment (TME) contribute to this dysfunctional state. Here we show that the biology of tumor-associated macrophages (TAM) and exhausted T cells (Tex) in the TME is extensively linked. We demonstrate that in vivo depletion of TAM reduces exhaustion programs in tumor-infiltrating CD8+ T cells and reinvigorates their effector potential. Reciprocally, transcriptional and epigenetic profiling reveals that Tex express factors that actively recruit monocytes to the TME and shape their differentiation. Using lattice light sheet microscopy, we show that TAM and CD8+ T cells engage in unique long-lasting antigen-specific synaptic interactions that fail to activate T cells, but prime them for exhaustion, which is then accelerated in hypoxic conditions. Spatially resolved sequencing supports a spatiotemporal self-enforcing positive feedback circuit that is aligned to protect rather than destroy a tumor.
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.