Modulation of lymphocyte proliferation induced by gastric MALT lymphoma-associated Helicobacter pylori strains.
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.
Ferrand
Jonathan
J
INSERM U853, Bordeaux, F 33076 France, and Université Victor Segalen Bordeaux 2, Bordeaux, F33076, France.
Roumanes
David
D
Pitard
Vincent
V
Moreau
Jean-François
JF
Mégraud
Francis
F
Lehours
Philippe
P
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