In vivo expression of the 25-kDa laminin-binding protein of Helicobacter pylori

The gastroduodenal pathogen Helicobacter pylori has been shown to inhibit the interaction between the extracellular matrix protein laminin and its receptor on gastric epithelial cells, potentially contributing to a loss of mucosal integrity. As a 25-kDa outer membrane protein of H. pylori in association with the bacterial lipopolysaccharides (LPS) mediates attachment to laminin, the aim of this study was to determine whether the 25-kDa protein is produced by H. pylori in infected hosts. We examined the immune response to the 25-kDa laminin binding protein in 12 paediatric patients; samples from a H. pylori-negative healthy adult were used as controls. In immunoblotting, antibodies to a 25-kDa protein were found in the serum and saliva of H. pylori-positive individuals only, and using the positive sera and saliva, laminin binding to the 25-kDa protein was inhibited. Thus, the 25-kDa laminin-binding protein is produced by H. pylori in infected hosts.