A new Helicobacter pylori vacuolating cytotoxin determinant, the intermediate region, is associated with gastric
Joanne L Rhead1, Darren P Letley, Marjan Mohammadi
1Wolfson Digestive Diseases Centre and Institute of Infection, Immunity and Inflammation, University of Nottingham, Nottingham, England.
Background & Aims:
Helicobacter pylori is the main cause of peptic ulceration and gastric adenocarcinoma. The vacuolating cytotoxin gene, vacA, is a major determinant of virulence. Two naturally polymorphic sites in vacA, the signal region and midregion, are well-characterized determinants of toxicity and markers of pathogenesis. The aim of this study was to characterize a new vacA polymorphic site, the intermediate (i) region.
Methods:
The vacA i-region was identified and characterized by constructing isogenic vacA exchange mutants and determining their vacuolating activity on HeLa, AGS, and RK13 cell lines. The vacA i-region types of H pylori isolates from patients undergoing routine endoscopy were determined by nucleotide sequencing and allele-specific polymerase chain reaction.
Results:
Two i-region types were identified, i1 and i2, and both were common among 42 Western clinical isolates. Interestingly, only naturally occurring s1/m2 strains varied in i-type; s1/m1 and s2/m2 strains were exclusively i1 and i2, respectively. Vacuolation assays showed that i-type determined vacuolating activity among these s1/m2 strains, and exchange mutagenesis confirmed that the i-region itself was directly responsible. Using a simple i-region polymerase chain reaction-based typing system, it was shown for 73 Iranian patients that i1-type strains were strongly associated with gastric adenocarcinoma (P < 10(-3)). Finally, logistic regression analysis showed this association to be independent of, and larger than, associations of vacA s- or m-type or cag status with gastric adenocarcinoma.
Conclusions:
Together these data show that the vacA i-region is an important determinant of H pylori toxicity and the best independent marker of VacA-associated pathogenicity.
More Related Videos
10:44One-step Negative Chromatographic Purification of Helicobacter pylori Neutrophil-activating Protein Overexpressed in Escherichia coli in Batch Mode
Published on: June 18, 2016
05:13Rapid Detection of Helicobacter pylori Virulence and Typing Using Quantum Dot Labeling Technology
Published on: June 13, 2025
Related Concept Videos
Pathophysiology of Peptic Ulcer Disease: Injurious Factors
In the antrum region, G cells secrete the gastrin hormone that binds to gastrin-cholecystokinin-B (CCK2) receptors on parietal and enterochromaffin-like (ECL) cells in the fundic glands. Simultaneously, the vagus nerve releases acetylcholine, which binds to M3...
Treating Helicobacter pylori in Peptic Ulcers: Antimicrobial Therapy
Microbiota of the Stomach and Small Intestine
Peptic Ulcer
Gastritis II: Pathophysiology
Peptic Ulcer Disease II: Pathophysiology
