Fluorescent Plaque Assay of Rubella Virus Infectivity

Plaques of rubella virus infected cells demonstrating granular, cytopathic fluorescence were counted in RK13 cell cultures fixed 72 hr after infection. There was a linear relationship between virus concentration and fluorescent plaque count. Counts on replicate cultures have demonstrated that the technique is very precise. The sensitivity of the fluorescent plaque assay was equal to that of the conventional GMK-interference titration method.