Rapid quantitative assay of cytomegalovirus infectivity.

A rapid quantitative assay was developed to determine cytomegalovirus infectious units. The assay yielded results in three days. The rapid quantitation of cytomegalovirus infectivity was developed by evaluating the number of cells that expressed cytomegalovirus-late antigens at the end of a single replication cycle (62 h post-infection). Late antigens were visualized by immunoalkaline phosphatase staining using a monoclonal antibody against the major viral capsid protein (66.8 kDa). Thirty-five cytomegalovirus samples were examined. The values of the infectious units obtained by immunoalkaline phosphatase staining were correlated significantly with the values determined by the classical plaque-forming technique.