Effect of secreting type and transmembrane type of tumor necrosis factor-α on the biological functions of neutrophils
Objective To compare the effect of transmembrane type tumor necrosis factor α (TM TNF α) and secreting type TNF α (S TNF α) on the biological functions of neutrophils so as to explore the role of the both type of TNF α in inflammation. Methods Effect of the two type of TNF α on the functions of neutrophils was examined by phagocytosis, respiratory burst and in situ hybridization assay. Results S TNF α was found to be able to promote neutrophil phagocytosis markedly ( P 0.001), induce a striking respiratory burst ( P 0.005) and enhance the expression of IL 1β mRNA in neutrophils, while TM TNF α showed little influence on them. TM TNF α caused a two fold increase in NO production by neutrophils ( P 0.001) while S TNF α in a wide dosage range(10 1?000U) failed to exert any effect on NO production. Conclusions These results suggested that the mechanisms of two type of TNF α may be explained as that S TNF α promotes the inflammation in early phase, while TM TNF α plays an important role in the regulation of inflammation.