Interleukin (IL)-17A is an important cytokine responsible for control of various microbial infections. IL-17A, IL-17F and the IL-17AF heterodimer are the signature cytokines produced by a particular type of CD4+ T-helper cell, designated as “Th17”. When dysregulated, Th17 cells and their cytokines contribute to the pathogenesis of autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis, psoriasis, and inflammatory bowel disease, among others. Thus far, research into the mechanisms of IL-17 action has focused on the effect of these cytokines on various cell types, including endothelial cells, epithelial cells, fibroblasts, neutrophils, monocytes/macrophages.