'Just 17 if you know what I mean' … but what do we really mean to say about Th17 immunity?

Th17-derived IL-17 might be considered the archetypal pro-inflammatory cytokine of adaptive immunity, to be targeted by new therapeutics for alleviation of autoimmune and inflammatory disease. However, the IL-17 family of cytokines is produced by diverse innate and adaptive cells, including Th17, Tc17, ILC3, NK cells and γδ T-cells. These responses are appreciated to underpin diverse aspects of protective, physiological immunity, from dialogue with the gut microbiota to bacterial and fungal immunity in the lung.