title: Studies with a human plasma-derived immunosuppressive, anti-lymphoma factor.
abstract: A low-molecular-weight (1,400) factor isolated from a human plasma alpha-globulin concentrate by acid-salt dissociation and ultrafiltration inhibits proliferation of mitogen-stimulated T cells and L1210 leukemia cells. The factor (UM05R) inhibits DNA, RNA, and protein synthesis in sensitive cells, acts in G1 of the cell cycle, and appears to suppress mitogen-responsive T cells without an accessory cell requirement. UM05R activity is enhanced by known cAMP-elevating agents and by sulfhydryl compounds. The results of the present study are consistent with the hypothesis that the plasma-derived agent inhibits lympho-proliferation as a result of elevation of intracellular cAMP.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D006131:Growth Inhibitors / Q000302:isolation & purification*; D006801:Humans; D007165:Immunosuppression Therapy; D007700:Kinetics; D007939:Leukemia L1210 / Q000276:immunology / Q000628:therapy; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008970:Molecular Weight; D014176:Protein Biosynthesis / Q000187:drug effects; D013601:T-Lymphocytes / Q000276:immunology; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D006131:Growth Inhibitors