Human IL-31 is a T cell-derived cytokine that shares several structural and functional characteristics with IL-6, Oncostatin M, LIF, and Cardiotrophin-1. It signals through a receptor complex comprised of GPL (also known as gp130-like receptor or IL-31RA) and Oncostatin-M receptor (OSMR). GPL/OSMR signaling is a strong activator of STAT3 and STAT5, and can also activate STAT1, JAK1, and JAK2 signaling pathways. IL-31-regulated immune responses have been implicated in skin physiology and inflammatory skin diseases. Recombinant Human IL-31 is a 15.8 kDa protein containing 141 amino acid residues.