Identification of novel immunogenic proteins of Helicobacter pylori by proteome technology.

Cell surface proteins of the human gastric pathogen Helicobacter pylori, reference strain CCUG 17874, were extracted with acid glycine and fractionated by heparin affinity chromatography. The extracts were subsequently analysed using high-resolution two-dimensional gel electrophoresis (2-DE) and immunoblotting. Four proteins of low molecular masses (25-30 kDa) stained by Coomassie R-350, were identified by peptide ESI-MS/MS sequencing after in-gel tryptic digestion. The identified proteins were recognised by sera from H. pylori-infected patients. Two of them are now described for the first time as immunogenic proteins of which one protein was determined to be distinct from all H. pylori proteins previously described. In addition, the specificity of the identified peptides was evaluated using both 1-D and 2-D immunoblotting against a panel of sera from patients with various bacterial infections. The present identification of highly specific antigens of H. pylori will encourage the improvement of serological diagnostic tests to diagnose and monitor H. pylori infection.