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World J Gastroenterol. May 21, 2014; 20(19): 5583-5593
Published online May 21, 2014. doi: 10.3748/wjg.v20.i19.5583
Immune responses to Helicobacter pylori infection
Mati Moyat, Dominique Velin
Mati Moyat, Dominique Velin, Service of Gastroenterology and Hepatology, Department of Medicine, Lausanne University Hospital, CH-1011 Lausanne, Switzerland
Author contributions: Moyat M and Velin D wrote the paper.
Supported by the Swiss National Foundation grants 310030_141145, to Velin D
Correspondence to: Dominique Velin, PhD, Service of Gastroenterology and Hepatology, Department of Medicine, Lausanne University Hospital, BH18-521, Rue du Bugnon 46, CH-1011 Lausanne, Switzerland. dominique.velin@chuv.ch
Telephone: +41-21-3140685 Fax: +41-21-3149653
Received: September 27, 2013
Revised: December 14, 2013
Accepted: February 20, 2014
Published online: May 21, 2014
Processing time: 232 Days and 21.3 Hours
Abstract

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 as γ-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 cytotoxin-associated 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.

Keywords: Helicobacter pylori; Vaccine; Immune response; Peptic ulcer; Gastric cancer

Core tip:Helicobacter pylori (H. pylori) infection is one of the most common infections in human beings worldwide. H. pylori actively induce tolerogenic signals and can be considered as a commensal bacteria belonging to the stomach microbiota. However, H. pylori also promote a chronic inflammation in the gastric mucosa and the direct action of virulence factors confers 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.