Fig. 2. IL-17F is produced by activated T cells and stimulates cytokine production. (A) IL-17F expression in T cells. Relative mRNA expression is shown. PI, treated with PMA and ionomycin. Induction of IL-8 (B) and G-CSF (C) in fibroblasts by IL-17F. Human primary foreskin fibroblasts were cultured for 24 h in the presence of the indicated concentrations of IL-17F. Conditioned medium was then analyzed by ELISA for the presence of IL-8 and G-CSF.