Roles of two tumor necrosis factor receptors in induction of differentiation of ML-1 cells.

The individual roles of two types of TNF receptors (55 kDa and 75 kDa) in induction of differentiation of human myeloblastic leukemia ML-1 cells were investigated using three monoclonal antibodies. The antibody htr-9, which recognizes the 55 kDa receptor, induced differentiation of ML-1 cells. Utr-1, which recognizes the 75 kDa receptor, blocked 125I-TNF binding by about 80% and inhibited by about 80% the TNF-induced NBT reducing activity. Htr-5 recognizes the 55 kDa receptor, blocked 125I-TNF binding by about 20% and inhibited by about 60% the TNF-induced NBT reducing activity. The data suggest that either of the two TNF receptors alone can mediate signals for the differentiation of ML-1 cells, and that simultaneous stimulation of both receptors will induce differentiation more effectively.