title: Stimulation of tumor cell growth in humans by a mononuclear cell-derived factor.
abstract: Serum-free supernatants of peripheral blood mononuclear cell cultures significantly stimulated [3H]thymidine incorporation of human hematopoietic and nonhematopoietic tumor cell lines. For assay we used a low number of tumor cells per well and medium enriched with dithiothreitol-treated fetal calf serum. The growth-stimulatory activity was detected in the supernatant of peripheral blood mononuclear cell culture within the first 24 h and decreased thereafter. Treatment of mononuclear cells with OKT3 monoclonal antibodies and rabbit complement decreased only moderately the factor production while treatment with anti-Leu-M2 and rabbit complement decreased it significantly. Supernatants of concanavalin A-stimulated peripheral blood mononuclear cell cultures enhanced nonsignificantly [3H]thymidine incorporation by tumor cell cultures unless antibodies against tumor necrosis factor alpha and gamma-interferon were added to the supernatants. Growth-stimulatory activity was heat inactivated partially at 60 degrees C and totally at 80 degrees C. It was abolished at pH 2.5 within 2 h as well as by treatment with dithiothreitol and partially lost by dialysis.
mesh_terms: D000911:Antibodies, Monoclonal; D001688:Biological Products / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D003470:Culture Media; D004229:Dithiothreitol / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007371:Interferon-gamma / Q000276:immunology; D015846:Monokines; D013936:Thymidine / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D001688:Biological Products; D003470:Culture Media; D015846:Monokines; D014409:Tumor Necrosis Factor-alpha; D003208:Concanavalin A; D007371:Interferon-gamma; D004229:Dithiothreitol; D013936:Thymidine