AUTOCRINE GROWTH BY 2 CYTOKINES, INTERLEUKIN-6 AND TUMOR NECROSIS FACTOR-ALPHA, IN THE MYELOMA CELL-LINE KHM-1A

The effects of tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) on the cell growth of the myeloma cell line KHM-1A were studied. TNF-α strongly induced KHM-1A proliferation, while IL-6 weakly enhanced growth only at low cell densities. When TNF-α was combined with IL-6, TNF-α-induced growth enhancement was reduced. According to Northern blotting analysis, the m-RNA of both TNF-α and IL-6 were detected in KHM-1A. Moreover, monoclonal antibody capable of neutralizing the cytotoxic activity of TNF-α inhibited the proliferation of this cell line. These findings suggest that this cell line operates under an autocrine growth mechanism with respect to these two cytokines, IL-6 and TNF-α