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

Abstract

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‐TNFβ monoclonal antibody but not affected by an anti‐TNFα antiserum. The data from this study suggest that TNFβ is involved in myeloma bone resorption, but not IL‐1, which is, however, known as one of the most potent OAF.