PRDM1 and colitis: However, adoptively transferred butyrate-treated Prdm1−/− Th1 cells induced colitis at levels similar to control Prdm1−/− Th1 cells in Rag−/− mice, suggesting that butyrate-treated Th1 cells could be endowed with regulatory properties like Tr1 cells in a Blimp-1-dependent fashion.