Analysis of Helicobacter pylori vacA gene and serum antibodies to VacA in Japan

Vacuolating cytotoxin, VacA, is one of the most important pathogenetic fact ors produced by Helicobacter pylori. However, it is not clear whether the d iversity in disease outcome may be ascribed to variations in strain and/or to the host responses to virulence factors. In this study, we analyzed the vacA middle region sequence among 65 Japanese isolates to clarify the varia tion in strain and assayed antibody titer to VacA by ELISA using purified V acA to evaluate the host response to cytotoxin. The nucleotide sequence ide ntities compared among Japanese isolates were 92.8 +/- 3.56%, and compared to 88.3 +/- 2.89% in tox(+) strains reported in GenBank. Positive correlati on was found between the antibody titers and the severity of atrophic chang e of the stomach. In Japan the nucleotide sequences of the vacA middle regi on were highly homologous and genetically closer to tox strains. Antibody t iters and host response to cytotoxin may be associated with atrophy of the stomach.