Description
Type 1 regulatory T (Tr1) cells are induced by the interleukin-27 (IL-27) and have critical roles in the control of autoimmunity and resolution of inflammation. Here, we show that the transcription factors IRF1 and BATF are induced early during treatment with IL-27 and are required for the differentiation and function of Tr1 cells in vitro and in vivo . Epigenetic and transcriptional analyses reveal that both transcription factors influence chromatin accessibility and expression of genes required for Tr1 cell function. IRF1 and BATF deficiencies uniquely alter the chromatin landscape, suggesting that these factors serve a pioneering function during Tr1 cell differentiation.