Immune responses to Helicobacter pylori infection

摘要

Helicobacter pylori(H.pylori)infection is one of the most common infections in human beings worldwide.H.pylori express lipopolysaccharides and flagellin that do not activate efficiently Toll-like receptors and express dedicated effectors,such asγ-glutamyl transpeptidase,vacuolating cytotoxin(vacA),arginase,that actively induce tolerogenic signals.In this perspective,H.pylori can be considered as a commensal bacteria belonging to the stomach microbiota.However,when present in the stomach,H.pylori reduce the overall diversity of the gastric microbiota and promote gastric inflammation by inducing Nod1-dependent pro-inflammatory program and by activating neutrophils through the production of a neutrophil activating protein.The maintenance of a chronic inflammation in the gastric mucosa and the direct action of virulence factors(vacA and cytotoxinassociated gene A)confer pro-carcinogenic activities to H.pylori.Hence,H.pylori cannot be considered as symbiotic bacteria but rather as part of the pathobiont.The development of a H.pylori vaccine will bring health benefits for individuals infected with antibiotic resistant H.pylori strains and population of underdeveloped countries.