Comparison of serum antibody titers to Helicobacter pylori lipopolysaccharides, CagA, VacA and partially purified cellular extracts in a Japanese population

We examined the levels of antibody titers against Helicobacter pylori antig ens, three types of lipopolysaccharides (LPSs), recombinant CagA antigen, r ecombinant VacA antigen and partially purified cellular antigens in the ser a of Japanese volunteers. The three types of LPSs are LPS carrying the high ly antigenic epitope, LPS carrying the weakly antigenic epitope and rough L PS, classified on the basis of antigenicity in humans. Ige titers against a ll H. pylori antigens tested were significantly different between gastroduo denal patients and healthy adults without H. pylori infection. IgG titers a gainst LPS carrying the weakly antigenic epitope, rough LPS and VacA antige n, as well as IgA titers against the partially purified cellular extract we re significantly higher in gastroduodenal patients than in H. pylori-positi ve healthy adults. However, IgG titers against LPS carrying the highly anti genic epitope, CagA antigen or the partially purified cellular extract show ed no significant difference between patients and H. pylori-positive health y adults. The results indicated that increases in IgG titers against VacA a ntigen and the weakly antigenic and core epitopes of LPS, and in IgA titer against the partially purified cellular extract, were associated with disea se state and may be useful in identifying active infection of H. pylori. (C ) 2000 Federation of European Microbiological Societies. Published by Elsev ier Science B.V. All rights reserved.