Animal-free IL-17 (IL-17A) is expressed in human 293 cells as a homodimeric glycoprotein with an apparent molecular mass of 30 to 35 kDa. The IL-17 family is comprised of at least 6 proinflammatory cytokines that share a conserved cystine-knot structure but diverage at the N-terminus. IL-17 family members are glycoproteins secreted as dimers that induce local cytokine production and recruit granulocytes to sites of inflammation.