Tumor necrosis factor alpha induces migration of human eosinophils

In order to evaluate the role of tumor necrosis factor alpha (TNF alpha) in the recruitment of eosinophils and neutrophils into the tissues, we studied the effect of TNF alpha on the migration of those cells in vitro, employing a modified Boyden's chamber technique. TNF alpha induced a significant migration of human eosinophils in a dose-dependent manner, and the preincubation of eosinophils with TNF alpha enhanced platelet activating factor (PAF)-induced eosinophil migration. Checkerboard analysis revealed that the eosinophil migration induced by TNF alpha was mainly due to chemokinesis. On the other hand, TNF alpha induced neither neutrophil migration nor enhancement of PAF-induced neutrophil migration. These results indicate that TNF alpha possesses a chemokinetic effect on human eosinophils and that TNF alpha augments the migration of eosinophils by PAF.