Identification of a decapeptide region of human interferon-α with antiproliferative activity and homology to an immunosuppressive sequence of the retroviral transmembrane protein P15E

We have identified a 10-amino acid sequence (amino acid, 9-18) from interferon-alpha (IFN-alpha) that when presented as a synthetic peptide inhibits both the proliferation of the Daudi lymphoblastoid cell line and the antigen receptor-stimulated proliferation of fresh human T lymphocytes. This sequence, which was identified by virtue of its sequence similarity (70% identity) to the immunosuppressive sequence of the retroviral transmembrane protein p15E, represents the smallest fragment of IFN-alpha that has been shown to date to be biologically active.