CD40-signalling abrogates induction of RORγt Treg cells by intestinal CD103 DCs and causes fatal colitis.

Immune homeostasis in intestinal tissues depends on the generation of regulatory T (Treg) cells. CD103 dendritic cells (DCs) acquire microbiota-derived material from the gut lumen for transport to draining lymph nodes and generation of receptor-related orphan γt (RORγt) Helios-induced Treg (iTreg) cells. Here we show CD40-signalling as a microbe-independent signal that can induce migration of CD103 DCs from the lamina propria (LP) to the mesenteric lymph nodes.