Description: IL-17A and IL-17F are members of the IL-17 family of proinflammatory cytokines. They share 50% amino acid sequence homology, which is the highest within the group. Both cytokines exist as homodimers although the individual subunits from each protein can also associate into a heterodimer known as IL-17AF.
Expression of IL-17A, F, and AF is most often associated with the Th17 subset of CD4+ T cells, but has also been observed in NKT cells and γδ T cells. They play an important role in the activation of neutrophils and induce inflammatory cytokine production in epithelial cells, endothelial cells, macrophages, and fibroblasts through NF-κB signaling. The heterodimer displays bioactivity intermediate to that of the two homodimers, with IL-17A being the most potent. IL-17AF and Th17 cells have been implicated in various autoimmune disorders, including rheumatoid arthritis, psoriasis, irritable bowel syndrome, and asthma.
