CD4 and colitis: Mice reconstituted with naive T cells showed a progressive weight loss and colitis development by day 50, while the prevention of weight loss, amelioration of immunopathology, and reduced CD4+ effector T cell numbers in colonic lamina propria and mesenteric lymph nodes (mLN) were observed in the presence of pentanoate-treated Bregs (Supplementary Fig. 4e, f).