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Virulence factors of Helicobacter pylori affecting its gastric colonization in Mongolian gerbils
1Research Laboratories, Yoshitomi Pharmaceutical Industries, Fukuoka, Japan.
Abstract:
Helicobacter pylori is recognized to possess a number of virulence factors. We investigated the role of motility, vacuolating cytotoxin, and urease in gastric colonization by H. pylori. Mongolian gerbils (SPF, 7 weeks old) were challenged orally with a single administration of a 24-h culture broth of H. pylori and then were killed 6 and 26 weeks after challenge. Gastric colonization, severe gastritis, ulceration, and high levels of serum anti-H. pylori immunoglobulin G were observed in the gerbils challenged with strains motile in the semisolid medium (ATCC43504, HPY-127, HPY-204), but not in gerbils challenged with strains nonmotile in the medium (ATCC49503, HPY-205, HPY-206). Only strains ATCC43504, ATCC49503, HPY-204, and HPY-206 had vacuolating cytotoxin activity against HeLa and Vero cells. Thus, motile strains were able to colonize regardless of their vacuolating cytotoxin activities, and vacuolating cytotoxin was not associated with epithelial damage in the gastric mucosa. Furthermore, the phenotypic variants of strains with the ability to colonize that lacked either motility or urease activity lost their ability to colonize. In conclusion, motility and urease activity, but not vacuolating cytotoxin activity, are essential for gastric colonization by H. pylori in Mongolian gerbils.
Insights
Motility and urease activity are essential for Helicobacter pylori (H. pylori) to colonize the stomach in gerbils. Vacuolating cytotoxin does not play a role in H. pylori colonization or cause gastric damage.
Area of Science:
- Microbiology
- Gastroenterology
- Infectious Diseases
Background:
- Helicobacter pylori is a significant human pathogen associated with various gastric diseases.
- Virulence factors are crucial for H. pylori's ability to establish and maintain infection in the stomach.
- Understanding the specific roles of these factors is key to developing effective treatment and prevention strategies.
Purpose of the Study:
- To investigate the essential virulence factors required for gastric colonization by H. pylori.
- To determine the specific roles of bacterial motility, vacuolating cytotoxin, and urease activity in H. pylori infection.
- To assess the contribution of these factors to gastric pathology in a Mongolian gerbil model.
Main Methods:
- Oral challenge of Mongolian gerbils with characterized H. pylori strains (motile/non-motile, with/without vacuolating cytotoxin and urease).
- Assessment of gastric colonization, gastritis, ulceration, and serum anti-H. pylori immunoglobulin G levels at 6 and 26 weeks post-infection.
- Phenotypic analysis of H. pylori variants to evaluate the loss of colonization ability upon loss of motility or urease activity.
Main Results:
- Motile H. pylori strains successfully colonized gerbil stomachs, inducing severe gastritis and ulceration, irrespective of vacuolating cytotoxin activity.
- Non-motile strains failed to colonize the gastric environment.
- H. pylori strains lacking either motility or urease activity lost their colonization capability, while vacuolating cytotoxin activity was not linked to epithelial damage.
Conclusions:
- Bacterial motility and urease activity are indispensable for H. pylori gastric colonization in Mongolian gerbils.
- Vacuolating cytotoxin activity is not essential for colonization and does not directly cause gastric mucosal damage in this model.
- These findings highlight key targets for therapeutic interventions against H. pylori infections.