Objective: To assess the contribution of the vacuolating cytotoxin to Helicobacter pylori virulence. Design: Approximately 50% of clinical isolates of H. pylori produce a potent vacuolating cytotoxin and a cytotoxin-associated protein with a molecular weight of 128 000 (CagA). A molecular genetic analysis of cytotoxin-positive and -negative strains was performed to clarify the effects of this cytotoxin in H. pylori virulence. Methods: We used the polymerase chain reaction and molecular cloning to obtain the gene coding for the cytotoxin. Cytotoxin-positive and -negative strains of H. pylori were analysed by DNA hybridization and the use of antisera raised against the recombinant cytotoxin. Results: We cloned the entire gene coding for the cytotoxin and raised antisera against the gene product. This gene proved to be unrelated to the gene coding for the cytotoxin-associated protein (cagA gene). The protein was not produced by cytotoxin-negative strains of H. pylori, although cagA gene sequences were present in the genome. Conclusions: Although the cagA gene was absent in cytotoxin-negative H. pylori strains, the cytotoxin gene was present, but not expressed, suggesting that the cagA gene may regulate cytotoxicity.

Telford, J.L., Dell'Orco, M., Burroni, D., Comanducci, M., Bugnoli, M., Figura, N., et al. (1993). Molecular analysis of the Helicobacter pylori cytotoxin gene. EUROPEAN JOURNAL OF GASTROENTEROLOGY & HEPATOLOGY, 5(Supplement 2), S22-S24.

Molecular analysis of the Helicobacter pylori cytotoxin gene

Figura, N.;
1993

Abstract

Objective: To assess the contribution of the vacuolating cytotoxin to Helicobacter pylori virulence. Design: Approximately 50% of clinical isolates of H. pylori produce a potent vacuolating cytotoxin and a cytotoxin-associated protein with a molecular weight of 128 000 (CagA). A molecular genetic analysis of cytotoxin-positive and -negative strains was performed to clarify the effects of this cytotoxin in H. pylori virulence. Methods: We used the polymerase chain reaction and molecular cloning to obtain the gene coding for the cytotoxin. Cytotoxin-positive and -negative strains of H. pylori were analysed by DNA hybridization and the use of antisera raised against the recombinant cytotoxin. Results: We cloned the entire gene coding for the cytotoxin and raised antisera against the gene product. This gene proved to be unrelated to the gene coding for the cytotoxin-associated protein (cagA gene). The protein was not produced by cytotoxin-negative strains of H. pylori, although cagA gene sequences were present in the genome. Conclusions: Although the cagA gene was absent in cytotoxin-negative H. pylori strains, the cytotoxin gene was present, but not expressed, suggesting that the cagA gene may regulate cytotoxicity.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11365/2657
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