Neutrophil activation by Helicobacter pylori lipopolysaccharides.

Helicobacter pylori-induced release of toxic substances by neutrophils could be of potential importance in the pathogenesis of gastroduodenal inflammatory diseases. Lipopolysaccharide (LPS) has the ability to induce neutrophil activation at very low concentrations. Neutrophil oxidative metabolism and enzyme release were assessed after stimulation of neutrophils with various preparations of LPS from H. pylori and compared with that obtained with Salmonella typhimurium LPS. No direct activation of neutrophils by LPS was observed. Preincubation with LPS showed a significant priming for increased activity on subsequent stimulation, particularly with rough-form LPS. The potency of H. pylori LPS was 10-fold lower than that of S. typhimurium LPS, probably reflecting the unique biochemical structure of H. pylori LPS. Chronic low-grade stimulation by H. pylori LPS in the gastric mucosa may render neutrophils primed for the excessive release of detrimental substances into the tissue on stimulation by other mediators.