Spontaneous secretion of tumor necrosis factor-beta by human myeloma cell lines

Abnormal bone remodelling in the vicinity of tumor cells is a common, early feature of multiple myeloma, characterized by excessive bone resorption which is mediated by local soluble factors called osteoclast activating factors (OAF). Since interleukin-1 (IL-1) and tumor necrosis factors (TNF) are potent, synergistic OAF produced by cells of the B-cell lineage, the authors investigated the spontaneous secretion of these cytokines by 11 human myeloma cell lines (HMCL). No HMCL secreted either IL-1, the most powerful OAF, or contra IL-1. In contrast, all of the lymphoblastoid cell lines assayed produced significant IL-1 activity. Ten of the 11 HMCL secreted a significant TNF activity. This was completely eliminated by an anti-TNF beta monoclonal antibody but not affected by an anti-TNF alpha antiserum. The data from this study suggest that TNF beta is involved in myeloma bone resorption, but not IL-1, which is, however, known as one of the most potent OAF.