The present invention relates to a novel IL-20 protein which is a member of the cytokine polypeptide family. In particular, isolated nucleic acid molecules are provided encoding the human IL-20 protein. IL-20 polypeptides are also provided as are vectors, host cells and recombinant methods for producing the same. The invention further relates to screening methods for identifying agonists and antagonists of IL-20 activity. Also provided are diagnostic methods for detecting immune system-related disorders and therapeutic methods for treating immune system-related disorders.
