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Cell vacuolization induced by Helicobacter pylori VacA toxin: cell line sensitivity and quantitative estimation
M de Bernard1, M Moschioni, E Papini
1Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Italy.
Toxicology Letters
|November 17, 1998
Summary
Helicobacter pylori cytotoxin VacA causes cell vacuolation. Standardizing the neutral red uptake assay revealed HeLa cells and specific conditions optimize VacA activity measurement.
Area of Science:
- Microbiology and Immunology
- Cell Biology
Background:
- Helicobacter pylori releases VacA, a major virulence factor.
- VacA induces intracellular vacuolation with acidic pH, accumulating weak bases.
- Neutral red uptake is the sole in vitro method to quantify VacA activity.
Purpose of the Study:
- To standardize the in vitro assay for quantifying VacA activity.
- To evaluate key parameters influencing VacA-induced vacuolation.
Main Methods:
- Tested various cell types, serum concentrations, cell densities, and toxin concentrations.
- Quantified VacA activity by measuring neutral red uptake in intoxicated cells.
- Identified optimal conditions for VacA-induced vacuolation using HeLa cells.
Main Results:
- HeLa cells demonstrated the highest sensitivity to VacA.
- VacA activity is influenced by multiple factors.
- Optimal vacuolation occurred at non-confluent cell density with low serum concentrations.
Conclusions:
- Standardization of the neutral red uptake assay is crucial for accurate VacA activity assessment.
- Optimized conditions enhance the reliability of VacA virulence factor studies.
- Findings provide a basis for reproducible in vitro analysis of H. pylori VacA.