IL-23 is essential for T cell-mediated colitis and promotes inflammation via IL-17 and IL-6.

This study shows that in these models, IL-23 is essential for manifestation of chronic intestinal inflammation, whereas IL-12 is not, and a critical target of IL- 23 is a unique subset of tissue-homing memory T cells, which are specifically activated by IL-21 to produce the proinflammatory mediators IL-17 and IL-6.