Bioactivity and immunological evaluation of LPS from different serotypes of Helicobacter pylori

BACKGROUND AND OBJECTIVES Helicobacter pylori is the causative agent of peptic ulcer disease and a co-factor in development of gastric malignancies. LPS are among toxic substances produced by H. pylori exhibiting low endotoxic activity compared to typical bacterial LPS. The aim of this study was to investigate bioactivity of LPS produced by different serotypes of Helicobacter pylori compared to Escherichia coli and Brucella abortus LPS. MATERIALS AND METHODS Bacterial LPS was extracted by the hot phenol-water method. Biological activities of LPS were determined via the limulus lysate assay, pyrogenic assay, and blood pressure and PBMC induction test in rabbits. RESULTS Biological activity of O2 serotype LPS of H. pylori was less than the biological activity of other H. pylori serotypes. CONCLUSION Our data supported the hypothesis that the unique bacterial LPS of the O2 serotype must be included in the formulation of a multivalent H. pylori vaccine.