IL-17 is a potent proinflammatory cytokine produced by activated memory T cells [1]. The IL-17 family is thought to represent a distinct signaling system that appears to have been highly conserved across vertebrate evolution [1].

1: IL-17: prototype member of an emerging cytokine family. Aggarwal S, Gurney AL; J Leukoc Biol 2002;71:1-8. PMID:11781375