Project description:Inhibiting PD1:PDL1 signaling has transformed therapeutic immune restoration. CD4 T cells are critical to sustain immunity in chronic infections and cancer, yet little is known about how PD1/L1 modulates CD4 T helper (Th) responses or the ability to restore CD4 Th-mediated immunity by inhibiting PD1/L1 signaling. We demonstrate that PD1/L1 specifically suppresses CD4 Th1 cell amplification, prevents CD4 Th1 cytokine production, and abolishes CD4 CTL killing capacity during chronic infection. Inhibiting PDL1 during chronic infection rapidly restored these functions, while simultaneously enhancing Th1-like Treg amplification and activation, indicating a system-wide CD4-Th1 recalibration. Paradoxically, PDL1-blockade decreased TCR signaling, while re-directing intrinsically-suppressive type I interferon networks towards dominant IFNγ-mediated responses. Mechanistically, PDL1-blockade specifically targeted defined populations with pre-established, but actively-suppressed proliferative potential, with limited impact on minimally-cycling TCF1+ Tfh, despite high PD1 expression. Thus, CD4 T cells require unique differentiation and functional states to be targets of PDL1-directed suppression and therapeutic restoration.
Project description:Inhibiting PD1:PDL1 signaling has transformed therapeutic immune restoration. CD4 T cells are critical to sustain immunity in chronic infections and cancer, yet little is known about how PD1/L1 modulates CD4 T helper (Th) responses or the ability to restore CD4 Th-mediated immunity by inhibiting PD1/L1 signaling. We demonstrate that PD1/L1 specifically suppresses CD4 Th1 cell amplification, prevents CD4 Th1 cytokine production, and abolishes CD4 CTL killing capacity during chronic infection. Inhibiting PDL1 during chronic infection rapidly restored these functions, while simultaneously enhancing Th1-like Treg amplification and activation, indicating a system-wide CD4-Th1 recalibration. Paradoxically, PDL1-blockade decreased TCR signaling, while re-directing intrinsically-suppressive type I interferon networks towards dominant IFNγ-mediated responses. Mechanistically, PDL1-blockade specifically targeted defined populations with pre-established, but actively-suppressed proliferative potential, with limited impact on minimally-cycling TCF1+ Tfh, despite high PD1 expression. Thus, CD4 T cells require unique differentiation and functional states to be targets of PDL1-directed suppression and therapeutic restoration.
Project description:Transcriptome analysis of CD4+ PD1+ T cells during LCMV CL13 infection Gene expression in WT and ERt2-cre;TGFbRII flox virus specific CD4 T cells Mixed chimeras of WT:ERt2cre+TGFbRII flox/flox were infected 9 days with LCMV and splenic CD4+ PD1+CD49d+ Cd8a- T cells sorted from each compartment by congenic marker
Project description:IL-10-producing CD4+ type-1 regulatory T cells (Tr1) promote immune tolerance during chronic infection, autoimmunity, and transplantation. However, specific Eomes-dependent stages of Tr1 differentiation and function remain unclear. Using preclinical models of bone marrow transplantation (BMT) and chimeric antigen receptor (CAR) T cell immunotherapy, we demonstrate a Tr1 differentiation trajectory in vivo from Eomes+IL-10– to Eomes+IL-10+ subsets with the acquisition of cytokine, cytolytic and exhaustion features. The Eomes+CD4+ fraction represents the dominant cytotoxic subset after BMT, mediating graft-versus-leukemia effects while limiting inflammation. In CD19-targeted CAR T cell immunotherapy, Eomes drives the same CD4+ Tr1 phenotype that controls cytolysis, whilst mitigating immune toxicity and promoting persistence. In patients receiving commercial CD19-targeted CAR T cells with long term disease control, Eomes+ Tr1 cells represent a stable population comprising 40-80% of the CD4+ CAR T cell population. Hence, Eomes controls both regulatory and cytotoxic programs in CD4+ T cells, essential for curative immunotherapy outcomes.
Project description:IL-10-producing CD4+ type-1 regulatory T cells (Tr1) promote immune tolerance during chronic infection, autoimmunity, and transplantation. However, specific Eomes-dependent stages of Tr1 differentiation and function remain unclear. Using preclinical models of bone marrow transplantation (BMT) and chimeric antigen receptor (CAR) T cell immunotherapy, we demonstrate a Tr1 differentiation trajectory in vivo from Eomes+IL-10– to Eomes+IL-10+ subsets with the acquisition of cytokine, cytolytic and exhaustion features. The Eomes+CD4+ fraction represents the dominant cytotoxic subset after BMT, mediating graft-versus-leukemia effects while limiting inflammation. In CD19-targeted CAR T cell immunotherapy, Eomes drives the same CD4+ Tr1 phenotype that controls cytolysis, whilst mitigating immune toxicity and promoting persistence. In patients receiving commercial CD19-targeted CAR T cells with long term disease control, Eomes+ Tr1 cells represent a stable population comprising 40-80% of the CD4+ CAR T cell population. Hence, Eomes controls both regulatory and cytotoxic programs in CD4+ T cells, essential for curative immunotherapy outcomes.
Project description:CD4+ T cells play a critical role in sustaining the effector function of CD8+ T cells during chronic viral infection. When CD4+ T cell “help” is absent, CD8+ T cells enter a dysfunctional state, losing their capacity for viral control. Here, we applied spatial transcriptomics to explore cellular localization and potential interaction between key immune cell subsets during chronic LCMV Clone 13 infection.
Project description:During acute viral infections, naïve CD4+ T cells differentiate into effector CD4+ T cells and, after viral control, into memory CD4+ T cells. Memory CD4+ T cells are highly functional, proliferate rapidly upon reinfection and persist long-term without antigen. In contrast, during chronic infections, CD4+ T cells become less functional. To compare the development of functional memory T cells with poorly functional T cells from chronic viral infection, we generated longitudinal transcriptional profiles for each.
Project description:Regulatory T (Treg) cells act as terminators in the case of T cell immunity during the acute phase of viral infection. However, their roles in chronic viral infection are not completely understood. We compared the phenotype and function of Treg cells during acute and chronic viral infection using lymphocytic choriomeningitis virus-infected mouse models. Chronic infection, unlike acute infection, led to induction of Treg cells and upregulation of various inhibitory receptors. Treg cells isolated from chronically infected mice (chronic Treg cells) displayed greater suppressive capacity for inhibiting T cell proliferation and subsequent cytokine production than those from naM-CM-/ve (naive Treg cells) or acutely infected mice (acute Treg cells). These gene expression profiles provided evidence that chronic Treg cells display characteristics distinct from either naive or acute Treg cells. Mouse splenic CD4+CD25+ regulatory T cells were analyzed at 0 day and 16 day after acute or chronic viral infection with LCMV Arm or CL13, respectively.
Project description:CD4+ T cells play a critical role in sustaining the effector function of CD8+ T cells during chronic viral infection. When CD4+ T cell “help” is absent, following transient CD4+ T cell depletion, CD8+ T cells enter a dysfunctional state, losing their capacity for viral control. Here, we applied scRNA-seq to determine the CD4+ T cell subsets that repopulate following transient CD4+ T cell depletion, during LCMV Clone 13 infection.