Effects of Helicobacter pylori vacuolating cytotoxin on primary cultures of human gastric epithelial cells

Abstract

Background. Many Helicobacter pylori strains produce a cytotoxin that induces cytoplasmic vacuolation in various types of eukaryotic cells. In contrast with the marked cell vacuolation that occurs in vitro in response to this cytotoxin, comparatively little epithelial vacuolation has been observed in the gastric mucosa of H. pylori infected persons. Aims. Experiments were performed to determine the susceptibility of human gastric epithelial cells in vitro to H. pylori vacuolating cytotoxin activity. Methods. Human gastric epithelial cells, harvested from upper gastrointestinal endoscopic biopsy specimens, were incubated overnight with broth culture supernatants from either a wild type cytotoxin producing (tox+) H. pylori strain or an isogenic mutant strain that lacks cytotoxin activity. Results. Prominent cytoplasmic vacuolation occurred in response to tox+ supernatant, but not supernatant from the isogenic mutant strain. Primary human gastic epithelial cells were significantly more sensitive to H. pylori vacuolating cytotoxin activity than were either HeLa or AGS cells. Exposure of human gastic epithelial cells to high concentrations of tox+ supernatant for 48 hours caused lethal cell injury. Conclusions. These studies indicate that primary human gastric epithelial cells are highly sensitive to H. pylori vacuolating cytotoxin activity.