Persistence of Helicobacter pylori VacA toxin and vacuolating potential in cultured gastric epithelial cells

Patrizia Sommi, Vittorio Ricci, Roberto Fiocca, Vittorio Necchi, Marco Romano, John L. Telford, Enrico Solcia, Ulderico Ventura

Research output: Contribution to journalArticle

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Abstract

The vacuolating toxin A (VacA) is one of the most important virulence factors in Helicobacter pylori-induced damage to human gastric epithelium. Using human gastric epithelial cells in culture and broth culture filtrate from a VacA-producing H. pylori strain, we studied 1) the delivery of VacA to cells, 2) the localization and fate of internalized toxin, and 3) the persistence of toxin inside the cell. The investigative techniques used were neutral red dye uptake, ultrastructural immunocytochemistry, quantitative immunofluorescence, and immunoblotting. We found that VacA 1) is delivered to cells in both free and membrane-bound form (i.e., as vesicles formed by the bacterial outer membrane), 2) localizes inside the endosomal-lysosomal compartment, in both free and membrane-bound form, 3) persists within the cell for at least 72 h, without loss of vacuolating power, which, however, becomes evident only when NH4Cl is added, and 4) generally does not degrade into fragments smaller than ~90 kDa. Our findings suggest that, while accumulating inside the endosomal-lysosomal compartment, a large amount of VacA avoids the main lysosomal degradative processes and retains its apparent molecular integrity.

Original languageEnglish
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume275
Issue number4 38-4
Publication statusPublished - 1998

Fingerprint

Stomach
Epithelial Cells
Helicobacter pylori
Membranes
Investigative Techniques
Neutral Red
Virulence Factors
Immunoblotting
Fluorescent Antibody Technique
Coloring Agents
Epithelium
Cell Culture Techniques
Immunohistochemistry
Helicobacter pylori VacA protein

Keywords

  • Outer membrane vesicles
  • VacA immunocytochemistry
  • VacA internalization
  • VacA metabolism

ASJC Scopus subject areas

  • Gastroenterology
  • Physiology
  • Physiology (medical)

Cite this

Persistence of Helicobacter pylori VacA toxin and vacuolating potential in cultured gastric epithelial cells. / Sommi, Patrizia; Ricci, Vittorio; Fiocca, Roberto; Necchi, Vittorio; Romano, Marco; Telford, John L.; Solcia, Enrico; Ventura, Ulderico.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 275, No. 4 38-4, 1998.

Research output: Contribution to journalArticle

Sommi, Patrizia ; Ricci, Vittorio ; Fiocca, Roberto ; Necchi, Vittorio ; Romano, Marco ; Telford, John L. ; Solcia, Enrico ; Ventura, Ulderico. / Persistence of Helicobacter pylori VacA toxin and vacuolating potential in cultured gastric epithelial cells. In: American Journal of Physiology - Gastrointestinal and Liver Physiology. 1998 ; Vol. 275, No. 4 38-4.
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