Extrathymically Generated Regulatory T Cells Establish a Niche for Intestinal Border-Dwelling Bacteria and Affect Physiologic Metabolite Balance (Immunity)

Extrathymically generated regulatory (pTreg) cells are induced by bacterial products at mucosal sites. In this issue, Campbell et al. show that pTreg cell deficiency impedes the establishment of a subset of intestinal bacteria due to heightened immune responses, with significant effects on host metabolites and fitness.