Abstract

CD8+ T cell exhaustion is a complex process that involves the differentiation of persistently activated CD8+ T cells into functionally distinct cell subsets. Here, we investigated the role of the key epigenetic regulator histone deacetylase 1 (HDAC1) in the differentiation of exhausted T (Tex) cells during chronic viral infection. We uncovered that HDAC1 controls the generation and maintenance of effector-like CX3CR1+ Tex cells in a CD8+ T cell-intrinsic manner. Deletion of HDAC1 led to expansion of an alternative Tex cell subset characterized by high expression of T cell exhaustion markers, and this was accompanied by elevated viremia. HDAC1 knockout altered the chromatin landscape in progenitor Tex cells, abrogated the expression of effector-like signature genes and interfered with cell fate specification toward the CX3CR1+ Tex cell subset. We conclude that HDAC1 is functionally required for controlling viral load during chronic infection by ensuring adequate CX3CR1+ Tex cell subset differentiation. HighlightsO_LIHDAC1 promotes the generation of CX3CR1+ effector-like Tex cell subsets in chronic viral infection in a CD8+ T cell-intrinsic manner. C_LIO_LIDeletion of HDAC1 leads to an increase of a cell subset enriched in exhaustion markers and is accompanied with elevated viremia. C_LIO_LIHDAC1 is required for the maintenance of the CX3CR1+ Tex cell pool. C_LIO_LIHDAC1 deletion alters the chromatin landscape at effector-like signature gene loci in progenitor Tex cells. C_LI