CD103+ GALT DCs promote Foxp3+ regulatory T cells.

There is evidence that Foxp3(+) regulatory T (T(R)) cells contribute to intestinal homeostasis and that deficiencies in this population can lead to chronic intestinal inflammation. Here, we review recent studies that demonstrate that the gut is a site of peripheral generation of T(R) cells. Functionally specialized gut dendritic cell populations promote T(R) cells through a transforming growth factor-beta and retinoic acid-dependent mechanism. Gut-driven T(R) cells may represent a tissue-specific mechanism to broaden the repertoire of T(R) cells focussed on the gut.