Serum immunoregulatory polypeptides and uses therefor

摘要

Previously unisolated serum immunoregulatory polypeptides (SIPs) having a molecular weight of approximately 14,000 to 31,000 are provided. The SIPs may be obtained from hemorrhagic serum of mammals and have been shown to activate suppressor T-cells and suppress lymphocyte proliferation and interleukin production. There is a significant homology between SIPs of different mammalian species. The amino acid sequence of an SIP having a molecular weight of about 16,000 is provided. In addition, immunosuppressive polypeptides are identified which have the formula (SEQ ID NO:2):X-Met-Asp-Ala-His-Pro-Pro-Arg-Leu-Phe-Ala-Cys-Ser-Ywherein X is an amino acid sequence having from 0 to 10 amino acids and Y is an amino acid sequence having from 0 to 110 amino acids.