Receptor Binding and Activation of Polymorphonuclear Neutrophils by Tumor Necrosis Factor-Alpha

The interaction of highly purified recombinant human tumor necrosis factor-alpha (rTNF. a) with human polymorphonuclear neutrophils (PMN5) was investigated. Binding of 1251. rTNF.a to PMN reached maximum levels in 30 mm at 37CC and In 2 h at 4C. Scatchard analysis of competitive binding data indicated approximately 6000 receptor sites per cell and a K.� of 1.37 nM. Binding data at 37CC indicated a rapid internalization of rTNF-a, Following this receptor-mediated interaction, recombinant TNF-a was found to inhibit the migration of PMN5 under agarose and to enhance PMN production of superoxide anion (O�) in a dose-dependent manner. Furthermore, rTNF-ct-activated PMNs caused a