Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. To determine the in vivo relevance of this phenomenon, we sought to detect cytotoxin-neutralizing antibodies in sera from H. pylori-infected persons. As a group, sera from 29 H. pylori-infected patients neutralized the activity of the purified cytotoxin to a significantly...

Helicobacter pylori VacA is a secreted toxin that induces multiple structural and functional alterations in eukaryotic cells. Exposure of VacA to either acidic or alkaline pH ('activation') results in structural changes in the protein and a marked enhancement of its cell-vacuolating activity. However, the mechanism by which activation leads to increased cytotoxicity is not well understood. In t...

To investigate the role of the Helicobacter pylori cytotoxin in the pathogenesis of gastritis, gnotobiotic piglets were colonized with either toxigenic H. pylori or a nontoxigenic isogenic mutant. Only piglets given the toxigenic strain developed toxin-neutralizing antibodies (indicating that toxin is expressed in vivo), but there was no difference in bacterial colonization, epithelial vacuolat...

Vacuolating cytotoxin A, VacA, is one of the major virulence factors produced by H. pylori and its gene polymorphism might play a major role in strain virulence of H. pylori itself. VacA is produced as a 140 kDa protoxin which undergoes multiple cleavage reactions to give an 88 kDa mature toxin. The 88 kDa protoxin is further cleaved by unknown proteases into 55 kDa C terminal domain (p55) and ...

AIM To investigate the association of gastric histological and endoscopic findings in patients with Helicobacter pylori (H. pylori), according to presence of seropositivity to 12 bacterial virulence antigens. METHODS This is a cross-sectional single-center study of 360 consecutive outpatients referred in the period of one year to upper gastrointestinal endoscopy because of dyspeptic complaint...

background : helicobacter pylori ( h. pylori ) infection is known as a major etiologic factor for a variety of gastroduodenal diseases. in iran, with a high rate of h. pylori infection close to 90%, numerous studies have revealed many aspects of interaction between the bacterium, mucosal surface and induction of disease outcome. the organism is genetically diverse and several virulence factors ...

Objective(s): Helicobacter pylori, a human specific gastric pathogen is a causative agent of chronic active gastritis. The vacuolating cytotoxin (VacA) is an effective virulence factor involved in gastric injury. The aim of this study was to construct a recombinant protein containing antigenic region of VacA gene and determine its antigenicity.   Materials and Methods: The antigenic region of V...

BACKGROUND The cag pathogenicity island includes a number of genes, including cytotoxin-associated protein A (cagA) and vacuolating cytotoxin (vacA) genotypes, which are associated with bacterial virulence. Although the role of cagA and vacA in the virulence of Helicobacter pylori (H. pylori) is well-established in epidemiological studies, the relationship between the cagA and vacA genotypes in...