A rapid assay for determination of antiviral activity against human cytomegalovirus.

RC256, the recombinant human cytomegalovirus (HCMV) which expresses beta-galactosidase, was used as a tool for rapid screening of compounds for antiviral activity. The effective concentration of antiviral compound needed to inhibit RC256 was identical to the concentrations needed to inhibit other strains of HCMV as measured by plaque reduction assay or virus yield reduction assay. Measurement of beta-galactosidase activity in infected cell lysates allowed determination of effective concentrations 48 h postinfection with results comparable to the longer, more laborious assays.