H pylori colocalises with MUC5AC in the human stomach

Background-The bacterium Helicobacter pylori is able to adhere to and to co lonise the human gastric epithelium, yet the primary gene product responsib le as a receptor for its adherence has not been identified. Aims-To investigate the expression of the gastric mucins MUC5AC and MUC6 in the gastric epithelium in relation to H pylori colonisation in order to ex amine their possible roles in the binding of H pylori. Patients-Seventy two consecutive patients suspected of having H pylori infe ction. Methods-MUC5AC, MUC6, and H pylori were detected in single sections of antr al biopsy specimens using immunohistochemical triple staining. Results-MUC5AC was expressed in the superficial epithelium and the upper pa rt of the gastric pits. MUC6 expression was detected in the lower part of t he gastric pits. The expression of both mucins in the epithelium was comple mentary. In each patient, there was a sharply delineated transition between MUC5AC and MUC6 producing cell populations. In all H pylori positive patie nts there was a striking colocalisation of H pylori and MUC5AC; more than 9 9% of the bacteria were associated with either extracellular MUC5AC or the apical domain of MUC5AC producing cells. Conclusion-H pylori is very closely associated with extracellular MUC5AC an d epithelial cells that produce MUC5AC. This indicates that MUC5AC, but not MUC6, plays a role in the adhesion of H pylori to the gastric mucosa.