TNF AND IL-6 ARE POTENT GROWTH-FACTORS FOR OH-2, A NOVEL HUMAN MYELOMA CELL-LINE

A novel human myeloma cell line, OH-2, was established from pleural fl uid of a myeloma patient in end stage of the disease. Effects of cytok ines on proliferation were analyzed by measuring uptake of H-3-thymidi ne. Cell surface antigens were detected by flow cytometry. The cell li ne is dependent on IL-6 for growth and proliferates in response to TNF . There is synergy between the stimulatory response of TNF and IL-6. T he cells express both the p55 and p75 TNF receptors. Neutralizing anti -IL-6 did not inhibit TNF-mediated proliferation, showing that TNF act s through a pathway that is independent of IL-6. TNF was more potent t han IL-6 in stimulating the growth of primary myeloma cultures (> 99% pure) from the same patient (OH-2-PC), indicating that TNF in selected myeloma patients has a growth-promoting effect equal to IL-6. OH-2 ce lls produce and secrete monoclonal IgG-kappa.