OPSONIC ACTIVITY OF SPECIFIC HUMAN-IGG AGAINST HELICOBACTER-PYLORI

There is a strong association between chronic gastroduodenal disease in adults and children and the recovery of Helicobacter pylori(formerly Campylobacter pylori) from gastric biopsy specimens. However, data relevant to host defense mechanisms directed against this organism are scarce. The ability of H. pylori-specificantibody and complement to enhance the in vitro phagocytosis and killing of H. pylori byhuman peripheral blood polymorphonuclear leukocytes (pMNL) were studied. Sera with IgG antibody to H. pylorifrom five children with culture-proven H. pylori gastric disease markedly enhanced complement-dependent phagocytosis of H. pyloriin an assay using flow cytometry to measure uptake of fluorescent-labeled bacteria by PMNL. Absorption of specific antibody from patient sera with an excessof H. pyloriorganisms completely abrogated this enhancement. IgG purified from plasma with high IgG antibody titers to H. pylorienhanced complement-dependent phagocytosis of H. pyloriand increased the killing of this organism by PMNL in the presence of5% human opsonic complement byone full log. IgG antibody to H. pylori appears to be highly functional in vitro in promoting complement-dependent phagocytosis and killing of H. pylori by PMNL. © 1990 by The University of Chicago.