Comparison of leukotriene B4-induced neutrophil migration through different cellular barriers.

Migration of neutrophils across epithelial or endothelial barriers in response to chemotactic stimuli occurs in inflammation and host defense. Leukotriene B4 (LTB4) may be synthesized by and certainly induces chemotaxis of neutrophils. To better understand the interaction between LTB4, neutrophils, and endothelium and epithelium, we compared the effects of LTB4 on human peripheral blood neutrophil migration through filters alone and on human umbilical vein endothelial (HUVE) cells and three different epithelial cell types, Madin-Darby canine kidney (MDCK) cells, human colon carcinoma (T84) cells, and rat type II alveolar cells, cultured on these filters. Significant LTB4-stimulated neutrophil migration occurred at the lowest (1 nM) dose and in the shortest period of time (15 min) across endothelial cells vs. all three epithelial cell types, and interestingly, vs. filters alone. Dose-response experiments (1-100 nM) indicated that at equimolar LTB4 concentrations neutrophil migration across endothelium was two- to threefold greater than that observed across filters alone and the three epithelial barriers. At higher LTB4 concentrations (100 nM), the degree of neutrophil migration through the three epithelial barriers was equivalent to that observed for filters alone. Overall, the data indicate that the various cellular barriers play an active role in inflammatory processes by regulating the transmigration of neutrophils in response to certain inflammatory chemotactic stimuli.