Fig. 1.

Regulation of IL-17A-producing human γδ T cells. Human Vγ2Vδ2 T cells are peripherally programmed to become Tγδ17 through the effects of IL-6, IL-1β, and TGF-β in the presence of HMBPP. These cells can then be maintained as Tγδ17 through the action of IL-23, IL-1β, and TGF-β, or they can acquire IFN-γ potential through IL-23 signaling. Tγδ1/17 T cells commonly lose the ability to produce IL-17A altogether and revert functionally to Tγδ1-like cells through IL-12 signaling