We describe two subclones of Helicobacter pylori, isolated contemporaneously from a human stomach, which differ markedly in the vacuolating cytotoxin gene, vacA, but whose near identity in sequences outside this locus implies a very recent common origin. The differences are consistent with homologous recombination with DNA from another strain and result in a changed vacA midregion and, importan...

There are two alleles of the vacuolating cytotoxin gene from Helicobacter pylori, which code for toxins with different cell specificities. By analyzing the phenotypes of natural and artificial chimeras between the two forms of the protein, we have delimited a short stretch of amino acids which determine the cell specificity.

A vacuolating cytotoxin encoded by vacA in Helicobacter pylori is known as a potential virulent determinant. The relationship between different vacA alleles, vacuolating ability, and H. pylori-related diseases was investigated. Genetic analysis of 119 isolates from Taiwanese patients revealed that 104 strains were s1a/m2, 13 strains were characterized as the s1a/m1T type, which was more homolog...

A Vibrio cholerae cytotoxin, designated VcVac, was found to cause vacuolation in Vero cells. It was originally detected in the pathogenic O1 Amazonia variant of V. cholerae and later shown to be produced in environmental strains and some El Tor strains. Comparison of VcVac production in various strains suggested that hemolysin was responsible for the vacuolating phenotype. Genetic experiments e...

Culture supernatants of nontoxigenic nonepidemic clinical strains of Vibrio cholerae belonging to diverse serogroups were found to induce vacuolation of nonconfluent HeLa cells. The vacuoles became prominent 18 h after introduction of culture supernatant, and vacuolated cells survived for 48 h and then died. Only a fraction of the vacuolated cells took up neutral red dye, implying that there we...

We show here that Helicobacter pylori broth culture supernatants disrupt the actin cytoskeleton of epithelial cell lines, leading to cell rounding and apoptosis through anoikis. We demonstrate that there are marked quantitative differences between strains and that there are different cell line sensitivities. By constructing VacA null isogenic mutants, we show that the effect is not due to the v...

The vacuolating cytotoxin of Helicobacter pylori, VacA, enters the cytoplasm of target cells and causes vacuolar degeneration by interfering with late stages of endocytosis. By using indirect immunofluorescence and flow cytometry, we have demonstrated that VacA binds to specific high-affinity cell surface receptors and that this interaction is necessary for cell intoxication.

We describe the rarity of Helicobacter pylori strains of vacuolating cytotoxin type s1a (the type most commonly associated with peptic ulceration in the United States) among black and mixed-race South Africans. We also provide the first description of a naturally occurring strain with the vacA allelic structure s2/m1.