DETERMINATION OF INFECTIOUS BURSAL DISEASE VIRUS TITRATION AND NEUTRALIZATION END-POINTS USING FLUOROGENIC STAINING

An automated method for determining infectious bursal disease virus (IBDV) titration and neutralization endpoints is described. The method employs the fluorogenic ester carboxyfluorescein-diacetate (CFDA) to stain cell monolayers in 96-well plates and a fluorescence-concentration analyzer. Titration results are compared with immunofluorescence and plaque assay titers. Virus-neutralization endpoint determination is objective, and the endpoints of replicate tests were equivalent or within one dilution of variability. Tests can be automatically screened as any percentage of a positive control or any standard deviation from a negative control.