Comparison between McCoy cell line and HeLa cell line for detecting Helicobacter pylori cytotoxicity: clinical and pathological relevance.

Background: Cell culture assay is an accurate test for detecting Helicobacter pylori cytotoxicity.

Aims: To evaluate McCoy cells for detecting Helicobacter pylori cytotoxicity by comparing with HeLa cells, and determine the association of cytotoxic strains with endoscopic and histological findings.

Methods: Helicobacter pylori isolates from 68 dyspeptic patients and 11 asymptomatic volunteers were tested. 180 microl (1.8 x 10(4) cells) of grown McCoy or HeLa cell suspension was seeded into each well of a 96-well microtitre tray and the medium was replaced once after 24 hours. Sonicate (20 microl) of each isolate was then added to the wells, in duplicate. After 24 and 48 hours incubation, intracellular vacuolation was assessed by inverted light microscopy.

Results: Using McCoy cells 57% of isolates showed cytotoxicity (23% weak and 34% strong), while using HeLa cells 30% of isolates showed strong cytotoxicity. All isolates toxic in HeLa cells were also toxic in McCoy cells. The prevalence of cytotoxic strains was not significantly different between the endoscopic findings; 50% in normal endoscopy, 60% in non-ulcer dyspepsia and 59% in peptic ulcer disease. However, cytotoxic strains were more common in subjects with severe histological gastritis than in those with normal mucosa or mild gastritis (66% vs 30%, p<0.01). Similarly, the prevalence of cytotoxic strains was also higher in subjects with active gastritis than in those without (64% vs 23%, p<0.01).

Conclusions: McCoy cells are more sensitive than HeLa cells for detecting Helicobacter pylori cytotoxicity in vitro. There is an association between cytotoxic strains and the severity and activity of histological gastritis.