Extraction of the Outer Membrane Proteins of H. pylori and Evaluation of Their Presence in Stool of the Infected Individuals

Helicobacter pylori infections are accompanied with the release of some antigenic material into the stool. Outer membranes proteins (OMP) are among the major antigens of bacteria, which in comparison with other bacterial constituents have less cross-reactivity. In this study, OMP of H. pylori were isolated from 11 clinical isolates and rabbit antiserum against them was used to detect possible antigens of H. pylori, which are released into the stool. We used immunoblotting and affinity chromatography to detect such antigens in fecal antigenic extracts of infected individuals. By immunoblotting, we were able to detect a 26 kDa band under reducing and non-reducing conditions, but many more antigens (at least 5 antigens with molecular weights of about 14, 26, 52, 57.5 and 66 kDa) were isolated by affinity chromatography. The 26 kDa antigen had a higher concentration and is seen in nearly all positive samples. Since the 26 kDa antigen is detectable by these two techniques, we suggest that this antigen is one of the major antigens of H. pylori which is released into the stool and can be considered as a candidate diagnostic antigen to be used in diagnostic kit development.