Effect of recombinant DNA-produced tumor necrosis factor on various parameters of neutrophil function.

The effect of recombinant DNA-produced human tumor necrosis factor (TNF) on various parameters of neutrophil function was evaluated. TNF was a weak direct activator of oxygen radical production. It released the specific granule contents to a limited extent, but the azurophilic granule contents were retained even in the presence of cytochalasin B. It had a chemotactic activity for neutrophils, as determined by the use of a modified Boyden's chamber. Pretreatment of neutrophils with TNF increased phagocytosis of opsonized particles and markedly potentiated in a dose-dependent manner oxygen radical production induced by opsonized zymosan. The inhibitors of lipoxygenase, but not those of cyclooxygenase, reduced the potentiating effect of TNF on phagocytosis, suggesting that the products of lipoxygenase play an important role in mediating the effect of TNF on neutrophils.