Abstract
Helicobacter pylori is a spiral microaerophilic Gram-negative bacterium which colonizes the mucus layer overlaying the gastric epithelium. Infection with H. pylori is associated with several gastrointestinal diseases, including gastritis, gastric ulcer, duodenal ulcer and gastric cancer. The blood-group antigen-binding adhesin (BabA) targeting human Lewisb surface epitopes is considered as an essential factor to mediate the epithelial attachment of H. pylori. Vacuolating toxin (VacA) is a protein of 87 kDa that has been shown to vacuolated epithelial cells. The aim of this study was to investigate the relationship between bab genotypes of H. pylori and different gastrointestinal diseases and to generate antibodies against BabA for further biochemical studies. The relationship with another clinically related cytotoxin, VacA, was also studied. The babA gene was detected in 73.23% of 127 clinical isolates. No significant difference was seen among different diseases. The proportion of vacAm1 (p = 0.011) and vacAm1/babA+ (p = 0.025) showed significant difference from gastric cancer and duodenal ulcer, respectively suggesting vacAm1 and vacAm1/babA+ genotype might be useful as a marker for gastric cancer. An intein-fused protein of BabA middle region from strain v344 (344L) was expressed in Escherichia coli. Polyclonal antibody raised against 344L was able to detect BabA in the crude extracts of babA+ strains. Two monoclonal antibodies against 344L, 2G2 and 16C4, were also obtained which would be useful to study the mechanism of H. pylori adherence to gastric epithelium.