[Cytotoxin vacuolization of Helicobacter pylori]

Helicobacter pylori is now recognized as the major causative agent of chronic superficial gastritis in humans. The virulence factors of H. pylori are still poorly understood. Vacuolating cytotoxin (VacA) is one of the factors that has been identified so far. VacA induces cytoplasmic vacuolation in eukaryotic cells. The vacA gene encodes a precursor protein of 140 kDa which consists of a 33-amino acid signal sequence, the 87 kDa cytotoxin and a 50 kDa C-terminal domain. The 50 kDa domain is involved in translocation of VacA across outer membrane. Sequence analysis of vacA gene derived from different strains of H. pylori revealed the existence of several families of vacA gene allels. Analysis of a clinically isolated strains of H. pylori showed the correlation between presence of specific vacA allels, VacA activity and peptic ulceration.