PRODUCTION OF CHEMOATTRACTANT BY HELICOBACTER-PYLORI

Helicobacter pylori is present in the antral region of the stomach in a majority of patients with gastritis type R The specific mechanism wh ereby the organism participates in the development of disease remains uncertain. Since the organism is not invasive, we postulate that H. py lori produces a chemoattractant that recruits inflammatory cells to th e antral region of the stomach. H. pylori was grown under microaerophi lic conditions at 37-degrees-C for 72-hr in Brucella broth containing 1% fetal bovine serum. Culture supernates were harvested after removal of organisms by centrifugation and filtration. The putative chemoattr actant in culture supernates as well as that which might be present en dogenously in the growth medium (negative control) was assayed against human neutrophils (PMN) in modified Boyden blind-well chambers using 3.0-mum membranes. We found that H. pylori supernates are chemotactic and showed up to 130% activity when compared to the positive chemoattr actant control (zymosan-activated serum, a source of C5a). Minimal act ivity was observed with virgin growth medium. The chemoattractant acti vity is proportional to the number of colony forming units (CFU) of H. pylori. Preliminary characterization of the activity shows that the c hemoattractant is stable in a boiling water bath for 15 min, activity is lost within 1 hr in acid or alkali, and the chemotactic factor has an approximate molecular weight of 8500 daltons. The factor has no ami no-sugar and is negative for the lipid A portion of lipopolysaccharide . The chemotactic factor may be related to the recruitment of PMN into the lamina propria of the stomach in patients with gastritis, and it may afford an additional target for design of unique therapeutic inter ventions in chronic gastritis.