NY CELLTILLVEXTREGLERANDE FAKTOR

摘要

Novel cell growth regulatory compositions are provided. The compositions are obtainable from leukocytes, e.g., human peripheral blood lymphocytes (PBLs) or human histiocytic lymphoma lines cultured with one or more inducers. The naturally occurring peptide can be obtained by careful purification of the conditioned medium of such cells and is shown to have selective inhibitory activity against certain cell lines and selective stimulatory activity against other cell lines. The polypeptide may be isolated from conditioned medium of cultured human PBLs or of histiocytic lymphoma cell lines, may be synthesized, or may be prepared by cloning of the gene in an appropriate host. Mutants and fragments are also provided.