Opsonophagocytosis of Campylobacter pylori

The opsonic activity of human serum from various sources against Campylobacter pylori was compared. All sera, whether from control subjects with no symptoms of gastritis or peptic ulceration, or from symptomatic patients from whom C. pylori had or had not been isolated, opsonised C. pylori equally well. Opsonisation depended on the alternative pathway of complement activation but not on antibody. These findings suggest that antibody plays no role in protection against C. pylori and that the presence of antibody in patients' sera is mainly of diagnostic value.