Immune responses to Helicobacter pylori infection

World J Gastroenterol. 2014 May 21;20(19):5583-93. doi: 10.3748/wjg.v20.i19.5583.


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

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Proteins / genetics
  • CD4-Positive T-Lymphocytes / immunology
  • Gastritis / immunology
  • Gastritis / microbiology
  • Gastrointestinal Tract / immunology
  • Gastrointestinal Tract / microbiology
  • Helicobacter Infections / immunology*
  • Helicobacter pylori*
  • Humans
  • Immunity, Innate
  • Immunoglobulin A / immunology
  • Immunoglobulin G / immunology
  • Inflammation / immunology
  • Inflammation / microbiology
  • Peptic Ulcer / immunology
  • Peptic Ulcer / microbiology
  • Stomach / immunology
  • Stomach / microbiology


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Immunoglobulin A
  • Immunoglobulin G