Interleukin-8 Production in Primary Cultures of Human Gastric Epithelial Cells Induced by Helicobacter pylori

Interleukin-8 (IL-8) production by the gastricmucosa is increased in Helicobacter pylori infection.Previous studies indicated that H. pylori induces IL-8synthesis in cancer cell lines, and the ability of H. pylori to stimulate IL-8 production issupposed to be associated with cag A and other cagpathogenicity island genes, including pic B gene. In thepresent study, we investigated the induction of IL-8 in primary cultures of normal human gastricepithelial cells to elucidate the IL-8 induction by wildtype strains and by the pic B knockout strain. Humangastric epithelial cells were obtained from surgically resected specimens from four patients. Three H.pylori strains (TN2F4; type 1 clinical isolate, TN2F4m1;isogenic pic B mutant of TN2F4, Tx30a; type 2 strain)were cocultured with the normal gastric epithelial cells or the transformed MKN-28. IL-8 levels inculture medium were determined by enzyme immunoassay.Human gastric epithelial cells produced IL-8 at a 10 -50times higher level than MKN-28 did when cocultured with TN2F4. The mutant TN2F4m1 induced IL-8 atsignificantly lower levels than the parent strain. Cellsfrom four patients behaved similarly on IL-8 production.The results of the present study demonstrated the induction of IL-8 in normal gastricepithelial cells, suggesting that pic B gene product mayplay an essential role in vivo.