Project description:Chronic viral infections represent a major public health problem. Although it is well understood that neonates and adults respond differently to chronic viral infections (HIV, HCV), the underlying mechanisms remain poorly understood. In this study, we transferred neonatal and adult CD8+ T cells into a mouse model of chronic infection (LCMV clone 13) and dissected out the key cell-intrinsic differences that alter their ability to protect the host. Interestingly, we found that neonatal CD8+ T cells preferentially become effector cells early in chronic infection when compared to adult CD8+ T cells, and resist commitment to the exhausted differentiation trajectory. Further, neonatal CD8+ T cells are preferentially maintained as stem-like exhausted progenitors rather than terminally exhausted cells during the chronic phase of infection. The altered differentiation trajectories of neonatal and adult CD8+ T cells is functionally significant, for the neonatal cells protect from viral replication. Together, our work demonstrates how cell-intrinsic differences between neonatal and adult CD8+ T cells influences key cell fate decisions during chronic infection.
Project description:Chronic viral infections represent a major public health problem. Although it is well understood that neonates and adults respond differently to chronic viral infections (HIV, HCV), the underlying mechanisms remain poorly understood. In this study, we transferred neonatal and adult CD8+ T cells into a mouse model of chronic infection (LCMV clone 13) and dissected out the key cell-intrinsic differences that alter their ability to protect the host. Interestingly, we found that neonatal CD8+ T cells preferentially become effector cells early in chronic infection when compared to adult CD8+ T cells, and resist commitment to the exhausted differentiation trajectory. Further, neonatal CD8+ T cells are preferentially maintained as stem-like exhausted progenitors rather than terminally exhausted cells during the chronic phase of infection. The altered differentiation trajectories of neonatal and adult CD8+ T cells is functionally significant, for the neonatal cells protect from viral replication at the cost of early-onset immunopathology. Together, our work demonstrates how cell-intrinsic differences between neonatal and adult CD8+ T cells influences key cell fate decisions during chronic infection.
Project description:Identifying signals that govern the differentiation of tumor-infiltrating CD8 + T cells (CD8 + TILs) towards exhaustion can improve current therapeutic approaches for cancer. Here, we show that type I interferons (IFN-Is) act as environmental cues enhancing terminal CD8 + T cell exhaustion in tumors. We found enrichment of IFNIs-stimulated genes (ISGs) within exhausted CD8 + T cells (Tex cells) in patients across various cancer types, with heightened ISG levels correlating with poor response to immune checkpoint blockade (ICB) therapy. In preclinical models, CD8 + TILs devoid of IFN-Is signaling developed less exhaustion features, provided better tumor control and showed greater response to ICB-mediated rejuvenation. Mechanistically, chronic IFN-Is stimulation perturbed lipid metabolism and redox balance in Tex cells, leading to aberrant lipid accumulation and elevated oxidative stress. Collectively, these defects promoted lipid peroxidation, which potentiated metabolic and functional exhaustion of Tex cells. Thus, cell intrinsic IFN-Is signaling regulates the extent of CD8+ TIL exhaustion, and has important implications for immunotherapy.
Project description:Identifying signals that govern the differentiation of tumor-infiltrating CD8 + T cells (CD8 + TILs) towards exhaustion can improve current therapeutic approaches for cancer. Here, we show that type I interferons (IFN-Is) act as environmental cues enhancing terminal CD8 + T cell exhaustion in tumors. We found enrichment of IFNIs-stimulated genes (ISGs) within exhausted CD8 + T cells (Tex cells) in patients across various cancer types, with heightened ISG levels correlating with poor response to immune checkpoint blockade (ICB) therapy. In preclinical models, CD8 + TILs devoid of IFN-Is signaling developed less exhaustion features, provided better tumor control and showed greater response to ICB-mediated rejuvenation. Mechanistically, chronic IFN-Is stimulation perturbed lipid metabolism and redox balance in Tex cells, leading to aberrant lipid accumulation and elevated oxidative stress. Collectively, these defects promoted lipid peroxidation, which potentiated metabolic and functional exhaustion of Tex cells. Thus, cell intrinsic IFN-Is signaling regulates the extent of CD8+ TIL exhaustion, and has important implications for immunotherapy.
Project description:Identifying signals that govern the differentiation of tumor-infiltrating CD8 + T cells (CD8 + TILs) towards exhaustion can improve current therapeutic approaches for cancer. Here, we show that type I interferons (IFN-Is) act as environmental cues enhancing terminal CD8 + T cell exhaustion in tumors. We found enrichment of IFNIs-stimulated genes (ISGs) within exhausted CD8 + T cells (Tex cells) in patients across various cancer types, with heightened ISG levels correlating with poor response to immune checkpoint blockade (ICB) therapy. In preclinical models, CD8 + TILs devoid of IFN-Is signaling developed less exhaustion features, provided better tumor control and showed greater response to ICB-mediated rejuvenation. Mechanistically, chronic IFN-Is stimulation perturbed lipid metabolism and redox balance in Tex cells, leading to aberrant lipid accumulation and elevated oxidative stress. Collectively, these defects promoted lipid peroxidation, which potentiated metabolic and functional exhaustion of Tex cells. Thus, cell intrinsic IFN-Is signaling regulates the extent of CD8+ TIL exhaustion, and has important implications for immunotherapy.
Project description:The failure of T-cells to control tumor growth has been associated with several functional defects that collectively lead to T-cell “exhaustion.” This phenotype results from chronic antigen stimulation within the tumor microenvironment, but how repetitive antigenic stimulation leads to T-cell exhaustion remains poorly defined. Here we show that persistent antigen stimulation induces mitochondrial oxidative stress that reduces tricarboxylic acid (TCA) cycle activity. The resultant bioenergetic compromise impairs nucleotide triphosphate synthesis, induces endoplasmic reticulum (ER) stress, and activates an exhaustion-associated gene expression program. Reversal of oxidative stress with N-acetylcysteine effectively restores T-cell proliferation, effector function, and memory-associated gene expression and enhances anti-tumor T-cell efficacy in vivo. These data reveal that induction of mitochondrial oxidative stress is a critical component of terminal T-cell dysfunction. Furthermore, treatments that restore mitochondrial redox are sufficient to prevent T-cell exhaustion and enhance anti-tumor immunity.