title: Immune responses to Helicobacter pylori infection.
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.
authors.affiliation: Mati Moyat, Dominique Velin, Service of Gastroenterology and Hepatology, Department of Medicine, Lausanne University Hospital, CH-1011 Lausanne, Switzerland.
authors.forename: Mati
authors.initials: M
authors.lastname: Moyat
authors.affiliation: Mati Moyat, Dominique Velin, Service of Gastroenterology and Hepatology, Department of Medicine, Lausanne University Hospital, CH-1011 Lausanne, Switzerland.
authors.forename: Dominique
authors.initials: D
authors.lastname: Velin
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D005756:Gastritis / Q000276:immunology / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000276:immunology / Q000382:microbiology; D016481:Helicobacter Infections / Q000276:immunology*; D016480:Helicobacter pylori; D006801:Humans; D007113:Immunity, Innate; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D007249:Inflammation / Q000276:immunology / Q000382:microbiology; D010437:Peptic Ulcer / Q000276:immunology / Q000382:microbiology; D013270:Stomach / Q000276:immunology / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G
keywords: Gastric cancer; Helicobacter pylori; Immune response; Peptic ulcer; Vaccine