Abstract
A rapid and sensitive assay method has been developed for herpes simplex virus in kidney cells of Cercopithecus aethiops. Using immunofluorescence, foci of infection produced by this virus can be scored within 20–22 hours after inoculation. It has been demonstrated that this procedure gives reproducible results and exhibits a direct relationship between virus concentration and the number of fluorescent foci. The technique is slightly more sensitive than the conventional plaque assay method using the same host system.