Induction of human beta-defensin-2 mRNA expression by Helicobacter pylori in human gastric cell line MKN45 cells on cag Pathogenicity Island

Helicobacter pylori is an etiological agent of gastritis, peptic ulcer, and gastric cancer. Human beta-defensin-2 (hBD-2) is an antimicrobial peptide which belongs to one of the most important host defense systems against bac terial infection in several epithelial tissues. We studied the effect of H. pylori on the expression of hBD-2 mRNA in MKN45 gastric mucosal cells. H. pylori, but not culture filtrate, increased the hBD-2 mRNA level in MKN45 c ells; the inductive effect of H. pylori was not detected with Intestine 407 cells. Among H. pylori strains, strain OHPC0002, which lacks a cag Pathoge nicity Island (PAI), did not induce hBD-2 mRNA in MKN45 cells. These result s suggested that H; pylori cag PAI is critical for the induction of hBD-2 m RNA in MKN45 cells. Exposure of MKN45 cells to Salmonella typhimurium, S. e nteritidis, S. typhi, and S. dublin, but not Escherichia coli ML35, also re sulted in induction of hBD-2 mRNA. (C) 1999 Academic Press.