SERUM ANTIBODY-RESPONSE AGAINST HELICOBACTER-PYLORI NCTC-11637 SMOOTH-LIPOPOLYSACCHARIDE AND ROUGH-LIPOPOLYSACCHARIDE PHENOTYPES IN PATIENTS WITH H-PYLORI-RELATED GASTROPATHY

The antigenicity of the Helicobacter pylori lipopolysaccharide (LPS) m olecule during the course of natural H. pylori infection in humans was investigated, The IgG and IgA responses against smooth (S)- and rough (R)-form LPS were evaluated in H. pylori positive patients with chron ic gastritis (CG, n = 30) and duodenal ulcer disease (DU, n = 16), and in 15 H. pylori-negative dyspeptic subjects. The results demonstrated that anti H. pylori LPS IgG and IgA antibody levels were significantl y enhanced in both groups of H. pylori-positive patients compared with H. pylori-negative subjects, thus confirming that H. pylori LPS is pa rt of the immunogenic antigen profile of the bacterium. In addition, a marked response against R-LPS, which significantly correlated with th at observed against S-LPS, was found for both IgG and IgA, thus indica ting that core oligosaccharide plays a powerful immunogenic role. Sinc e the O-side chain of LPS from H. pylori NCTC 11637 contains epitopes which mimic Lewis x (Le(x)) antigens, the presence of antibodies to mo nomeric, trimeric, and polymeric Le(x) was also investigated. Antibodi es against polymeric Le(x) were detected in two patients suffering fro m chronic atrophic gastritis and active chronic gastritis, respectivel y.