Related Experiment Videos
Modulatory action of Helicobacter pylori on histamine release from mast cells and basophils in vitro
D A Lutton1, K B Bamford, B O'Loughlin
1Department of Clinical Biochemistry, Queen's University of Belfast.
Abstract:
Helicobacter pylori is important in the aetiology of peptic ulceration. Despite inducing an inflammatory response in the mucosa, the organism persists, suggesting that it has efficient protective mechanisms. Some bacterial and viral products modulate histamine secretion from inflammatory cells. Therefore, this study examined the modulatory effects of H. pylori preparations on histamine release from rat peritoneal mast cells and human basophils. Eleven clinical isolates of H. pylori were prepared in different ways: as whole washed bacteria, washed sonicated bacteria, and formalin-killed bacteria, and as outermembrane and lipopolysaccharide (LPS) extracts. Histamine release from mast cells or basophils was not elicited by any of these bacterial preparations alone. However, when mixed with various secretory stimulants, the bacterial preparations caused inhibition of histamine release from rat mast cells (calcium ionophore A23187, compound 48/80, concanavalin A, anti-rat IgE) and human basophils (A23187, N-formyl Met-Leu-Phe). The degree of inhibition ranged from 48% to 97%. These results indicate that H. pylori exerts an inhibitory effect on cells of the immune system that contributes to its persistence within the gastric mucosa.
Insights
Helicobacter pylori preparations inhibit histamine release from immune cells. This immune modulation by H. pylori may explain its persistence in the stomach.
Area of Science:
- Immunology
- Microbiology
- Gastroenterology
Background:
- Helicobacter pylori is a key factor in peptic ulcer disease.
- H. pylori persists in the gastric mucosa despite causing inflammation, indicating effective evasion strategies.
- Bacterial and viral components can influence histamine release from immune cells.
Purpose of the Study:
- To investigate the modulatory effects of H. pylori preparations on histamine secretion.
- To determine if H. pylori impacts histamine release from rat mast cells and human basophils.
Main Methods:
- Prepared H. pylori isolates as whole bacteria, sonicated bacteria, formalin-killed bacteria, outer membrane extracts, and lipopolysaccharide (LPS) extracts.
- Assessed histamine release from rat mast cells and human basophils stimulated by various agents.
- Measured the effect of H. pylori preparations on histamine release.
Main Results:
- No H. pylori preparation alone induced histamine release.
- H. pylori preparations significantly inhibited histamine release from both rat mast cells and human basophils when combined with secretagogues.
- Inhibition levels ranged from 48% to 97%.
Conclusions:
- H. pylori possesses mechanisms to inhibit histamine release from immune cells.
- This immune-inhibitory effect likely contributes to H. pylori's persistence in the gastric environment.
- Understanding these mechanisms could offer new therapeutic targets for H. pylori infections.