title: Cell-culture system for continuous production of Toxoplasma gondii tachyzoites.
abstract: The aim of this study was to identify a sustainable cell line and culture method that could continuously provide a sufficient quantity of Toxoplasma gondii tachyzoites to serve the needs of a general hospital laboratory. Three continuous cell lines (HeLa, LLC and Vero) and three cell-culture methods (culture in conventional flasks, culture in membrane-based flasks and an automated culture system) were investigated. In multiplicity-of-infection and time-course experiments, HeLa was the cell line of choice. Harvests from HeLa cells had significantly higher tachyzoite yields than those from LLC cells (P<0.00005) or Vero cells (P<0.05). Membrane-based flasks gave higher yields (6.15x10(6) tachyzoites/ml) than conventional flasks (1-2x10(6) tachyzoites/ml) initially, but these were not sustained. The automated cell-culture system was unsuitable for parasite culture. Continuous passage in 25 cm2 flasks was successful, yielding 1x10(6) tachyzoites/ml; viability exceeded 90% after 96-120 h of infection throughout 38 passes, during which time the viability improved and the time to harvest became more consistent. Toxoplasma gondii grown in continuous culture in HeLa cells can provide a regular supply of viable tachyzoites. Demonstration that HeLa-derived tachyzoites could be used for the dye test confirms the potential of this in vitro system for use in general hospital laboratories.
authors.affiliation: Microbiology Department, Raigmore Hospital, Highland Acute Hospitals NHS Trust, Scotland, UK.
authors.forename: R
authors.initials: R
authors.lastname: Evans
authors.forename: J M
authors.initials: JM
authors.lastname: Chatterton
authors.forename: D
authors.initials: D
authors.lastname: Ashburn
authors.forename: A W
authors.initials: AW
authors.lastname: Joss
authors.forename: D O
authors.initials: DO
authors.lastname: Ho-Yen
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods*; D002460:Cell Line; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D008751:Methylene Blue; D051381:Rats; D014122:Toxoplasma / Q000254:growth & development*; D014709:Vero Cells
chemical_list: D008751:Methylene Blue