Antibody response to Helicobacter pylori excretory antigen and the cross reaction study.

Helicobacter pylori is recognized as a major case of gastritis and peptic ulcer and a key factor in the development of gastric cancer, gastric lymphoma, and non-ulcerative dyspepsia in man. The detection of antibodies specific for strains of H. pylori has demonstrated the value of serology for providing evidence of infection. The present study was conducted to detect the antigenic proteins of excretory antigen of H. pylori with Western blotting and examine whether anti-H. pylori IgG and IgA antibodies from H. pylori positive patients cross-react with antigens from other common bacterial pathogens. By using SDS-PAGE, 20 different proteins were found in the excretory antigen. By Western blotting and absorption studies, there were indications that anti-H. pylori IgA antibodies directed against 54 kDa, 50 kDa and 27 kDa cross-reacted with antigens from other bacteria, and that H. pylori proteins of 99 kDa, 88 kDa and 81 kDa possibly shared similar epitope with antigens of other pathogens not tested in the absorption studies. The cross-reactivity occurred in this study was not significantly affect the performance of the in-house ELISA.