title: Modulation of lymphocyte proliferation induced by gastric MALT lymphoma-associated Helicobacter pylori strains.
abstract: BACKGROUND
  Helicobacter pylori infection leads to different chronic diseases, suggesting that this bacterium can evade the host immune defense system. The ability to control lymphocyte proliferation may be a mechanism leading to the development of gastric pathologies. Our aim was to characterize the effects of mucosa-associated lymphoid tissue (MALT) associated H. pylori strains on lymphocyte proliferation.
  
  
  METHODS
  We measured the in vitro proliferation of human lymphocytes originally from blood or tonsil samples in the presence or absence of viable bacteria or lysates.
  
  
  RESULTS
  We showed that MALT lymphoma-associated strains are not likely to be directly responsible for anarchical B-cell proliferation in vitro. On the other hand, proliferation of prestimulated T lymphocytes was abolished in vitro by the presence of all H. pylori strains, whether associated with MALT lymphoma or not.
  
  
  CONCLUSIONS
  Inhibition of T-cell proliferation may be of major importance in the gastric colonization and in the persistence of the infection. Furthermore, this inhibition may favor anarchical B-cell proliferation in vivo and predispose the host to gastric MALT lymphoma, whereas MALT-associated H. pylori strains do not appear to possess a specific capability to directly stimulate B-lymphocyte proliferation.
authors.affiliation: INSERM U853, Bordeaux, F 33076 France, and Université Victor Segalen Bordeaux 2, Bordeaux, F33076, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Ferrand
authors.forename: David
authors.initials: D
authors.lastname: Roumanes
authors.forename: Vincent
authors.initials: V
authors.lastname: Pitard
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Moreau
authors.forename: Francis
authors.initials: F
authors.lastname: Mégraud
authors.forename: Philippe
authors.initials: P
authors.lastname: Lehours
mesh_terms: D049109:Cell Proliferation; D005753:Gastric Mucosa / Q000382:microbiology*; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000145:classification / Q000502:physiology*; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D018442:Lymphoma, B-Cell, Marginal Zone / Q000276:immunology / Q000382:microbiology* / Q000473:pathology