RT Journal Article
SR Electronic
T1 Toxoplasma dye test using cell culture derived tachyzoites
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 630
OP 633
DO 10.1136/jcp.53.8.630
VO 53
IS 8
A1 D Ashburn
A1 R Evans
A1 J M W Chatterton
A1 A W L Joss
A1 D O Ho-Yen
YR 2000
UL http://jcp.bmj.com/content/53/8/630.abstract
AB Aims—To assess the diagnostic usefulness of Toxoplasma gondii tachyzoites produced by serial passage in HeLa cell culture. Methods—Tachyzoites derived from serial passage in cell culture were used in the dye test. Human sera were also examined to determine their suitability for use as accessory factor. Using the optimum conditions, the dye test using cell culture derived tachyzoites was compared with the current method of production (animal culture) on 105 randomly selected sera. Start up and maintenance costs of each system were compared. Results—Tachyzoites in most cell culture harvests (84%) from both early and later passes were useable. Tachyzoite yield and viability were maintained during serial passage in cell culture. Sodium citrate was used to modify accessory factor and improve its suitability. The performance of the accessory factor was improved by the addition of 1% and 3% sodium citrate for the current and cell culture systems, respectively. Under optimum conditions, dye test titres using cell culture and current systems were compared on 105 randomly selected sera. The results from 92 of 105 (87.6%) patients agreed or were within one dilution, but all discrepancies were resolved on re-testing. Start up costs for the current system would be 2.5 times and overall maintenance three times more expensive than cell culture. Conclusions—Tachyzoites derived from cell culture can be used routinely in the dye test. Production in cell culture is more cost effective than animal culture. It is possible for general hospitals to perform the dye test, thus obtaining faster and more specific results.