Cell vacuolization induced by Helicobacter pylori VacA toxin: cell line sensitivity and quantitative estimation.
A major virulence factor released by Helicobacter pylori is a protein toxin, termed VacA, which induces the formation of large intracellular vacuoles characterised by a lumenal acidic pH. Consequently they accumulate membrane permeable weak bases. The increase in neutral red uptake by intoxicated cells is the only known in vitro procedure to estimate quantitatively the activity of VacA. With the goal to standardize this assay, several parameters were evaluated: cell type, serum concentration, cell density and toxin concentration. Among the different cell types tested, HeLa cells were found to be the most sensitive to VacA. Results show that several factors contribute to VacA activity and that optimal vacuolation is achieved at non-confluent cell density, in the presence of low serum concentrations.
de Bernard
M
M
Centro CNR Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, Italy.
Moschioni
M
M
Papini
E
E
Telford
J
J
Rappuoli
R
R
Montecucco
C
C
D001426:Bacterial Proteins / Q000633:toxicity*; D001427:Bacterial Toxins / Q000633:toxicity*; D002452:Cell Count; D002478:Cells, Cultured; D003603:Cytotoxins / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D009499:Neutral Red / Q000378:metabolism; D012680:Sensitivity and Specificity; D014617:Vacuoles / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; C074689:VacA protein, Helicobacter pylori; D009499:Neutral Red