Development and maintenance of intestinal regulatory T cells

Gut-resident forkhead box P3 (FOXP3)(+)CD4(+) regulatory T cells (T-reg cells) are distinct from those in other organs and have gut-specific phenotypes and functions. Whereas T-reg cells in other organs have T cell receptors (TCRs) specific for self antigens, intestinal T-reg cells have a distinct set of TCRs that are specific for intestinal antigens, and these cells have pivotal roles in the suppression of immune responses against harmless dietary antigens and commensal microorganisms. The differentiation, migration and maintenance of intestinal T-reg cells are controlled by specific signals from the local environment. In particular, certain members of the microbiota continuously provide antigens and immunoregulatory small molecules that modulate intestinal T-reg cells. Understanding the development and the maintenance of intestinal T-reg cells provides important insights into disease-relevant host-microorganism interactions.