Helicobacter pylori strain-specific differences in genetic content, identified by microarray, influence host
D A Israel1, N Salama, C N Arnold
1Division of Gastroenterology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
The Journal of Clinical Investigation
|March 10, 2001
Summary
Helicobacter pylori strains differ in their ability to cause disease. An intact cag pathogenicity island in H. pylori is crucial for inducing inflammation and host cell responses, impacting ulcer development.
Area of Science:
- Microbiology
- Pathogenesis
- Host-pathogen interactions
Background:
- Helicobacter pylori infection is a major risk factor for peptic ulcers and gastric cancer.
- However, only a small percentage of infected individuals develop severe disease, suggesting strain-specific virulence factors are involved.
Purpose of the Study:
- To investigate differential host responses induced by two H. pylori isolates.
- To identify bacterial genetic determinants associated with pathogenesis using whole genome microarrays.
Main Methods:
- Comparison of gastric ulcer strain B128 and duodenal ulcer strain G1.1 in gerbil models (in vivo) and cell cultures (in vitro).
- Utilized H. pylori whole genome microarrays to analyze gene composition differences between strains.
- Assessed host responses including gastritis, proliferation, apoptosis, and IL-8 secretion.
Main Results:
- Gastric ulcer strain B128 induced more severe gastritis, proliferation, apoptosis, and gastric lesions in gerbils compared to duodenal ulcer strain G1.1.
- H. pylori strain G1.1 exhibited a deletion in the cag pathogenicity island, which was absent in strain B128.
- Disruption of the cag island in strain B128 attenuated IL-8 induction and reduced gastric inflammation in vivo.
Conclusions:
- The cag pathogenicity island is essential for H. pylori to modulate epithelial cell responses and induce inflammation.
- Whole genome microarrays are effective for identifying genetic differences between H. pylori strains correlating with distinct pathological outcomes.
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