IL‐17D is a disulfide‐linked homodimer of two 185 amino acid polypeptide chains. It belongs to the IL‐17 family of structurally‐related cytokines that share a highly conserved C‐terminal region, but differ from one another in their N‐terminal regions and in their distinct biological roles. The six known members of this family, IL‐17A through IL‐17F, are secreted as homodimers. IL‐17D has the ability to stimulate the production of IL‐6, IL‐8 and GM‐CSF, and inhibits hemopoiesis of myeloid progenitor cells in colony‐forming assays. Recombinant Murine IL-17D is a 40.6 kDa, disulfide-linked homodimer of two 183 amino acid, polypeptide chains.