The IL-17 family of cytokines contains six members: IL-17 (also known as IL-17A), IL-17B, IL-17C, IL-17D, IL-17E (also known as IL-25) and IL-17F. These cytokines consist of 163-202 amino acids with molecular masses of 20-30 kDa. They share four conserved cysteine residues at the C-terminal region that may participate in the formation of intermolecular disulfide linkages. IL-17A is the most extensively researched cytokine in this family. It is a disulfide-linked homodimeric glycoprotein which binds to and activates a heterodimeric transmembrane receptor complex consisting of IL-17RC and IL-17RA subunits...