The microbiota regulates type 2 immunity through RORγt ⁺ T cells

TLDR

Gut microbiota shape intestinal T cell populations, with Clostridium species inducing regulatory T cells that promote host–microbe tolerance. The authors identified a microbiota‑dependent RORγt⁺ regulatory T cell subset essential for immune homeostasis; mice lacking this transcription factor were more susceptible to colitis and displayed elevated allergy‑associated proinflammatory mediators. Ohnmacht et al.

Abstract

Gut microbes make T cells keep the peace Our guts harbor trillions of microbial inhabitants, some of which regulate the types of immune cells that are present in the gut. For instance, Clostridium species of bacteria induce a type of T cell that promotes tolerance between the host and its microbial contents. Ohnmacht et al. and Sefik et al. characterized a population of gut regulatory T cells in mice, which required gut microbiota to survive. Multiple bacterial species of the microbiota could induce transcription factor–expressing regulatory T cells that helped maintain immune homeostasis. Mice engineered to lack these transcription factors exhibited enhanced susceptibility to colonic inflammation and had elevated amounts of proinflammatory molecules associated with allergies (see the Perspective by Hegazy and Powrie). Science , this issue pp. 989 and 993