ANALYSIS OF INTERLEUKIN-8 SECRETION INDUCED BY HELICOBACTER-PYLORI FROM THE GASTRIC EPITHELIAL-CELL LINE MKN45 - A MECHANISM INDEPENDENT OFTHE INTENSITY OF CYTOTOXICITY

Interleukin (IL)-8, a potent chemoattractant and activator of neutroph ils, has been implicated to have a major role in the pathogenesis of g astric mucosal injury by Helicobacter pylori infection. We examined th e relationship between cytotoxicity and IL-8 secretion induced by H, p ylori. Furthermore, whether the vacuolating cytotoxin of H. pylori med iates IL-8 secretion from gastric epithelial cell lines was examined. Among the inflammatory cytokines, messages for IL-6, IL-8 and transfor ming growth factor-beta(1) were produced by gastric cancer (MKN45) cel ls in response to exposure to the cytotoxic strain of H. pylori. MKN45 incubated with the viable cytotoxic strain of N. pylori secreted IL-8 . In contrast, the supernatant. of neither the cytotoxic nor the non-c ytotoxic strain induced IL-8 secretion. There was no correlation betwe en IL-8 secretion and the intensity of cytotoxicity. In conclusion, th ese findings suggest that IL-8 secretion from MKN45 induced by H. pylo ri is mediated by factors other than cytotoxicity.