MUTAGENICITY FROM NEUTROPHILS AFTER CHALLENGE WITH HELICOBACTER-PYLORI AND BILE

Objective: To study some mechanisms involved in Helicobacter pylori (H pylori)-induced gastric carcinogenesis. Design: In vitro study. Setti ng: Medical centre hospital, Sweden. Interventions: Mutagenicity in Am es' test of neutrophils challenged for 2 hours or more by two differen t strains of H pylori. One strain designated NCTC 11637 by the Nationa l College of Type Cultures activated neutrophils to an oxidative burst and producing vacuolating cytotoxin, the other strain C-7050 lacked t hese abilities. Mutagenicity was also studied with sterile human gall bladder bile alone added to neutrophils or in combination with both ne utrophils and H pylori. Results: There was no increase in the number o f revertants with the crude suspension or the supernatant of neutrophi ls challenged for 1 hour or less with H pylori, bile, or the combinati on of both. However, in 5 out of 19 experiments there was significant mutagenicity after challenge of neutrophils for 2 hours or more with e ither strain of H pylori, bile, or the combination of the two. The str ongest mutagenicity was obtained after challenge over night (18 hours) with the combination of H pylori and bile. Conclusion: Mutagenicity o ccurs when neutrophils are challenged with H pylori and bile. Factors other than reactive oxygen metabolites seem to be responsible.