Rapid detection of cytomegalovirus in cell culture by indirect immunoperoxidase staining with monoclonal antibody to an early nuclear antigen

A method for the rapid detection of cytomegalovirus (CMV) in MRC-5 cells 48 h after inoculation with clinical specimens was developed. A commercially available monoclonal antibody to a CMV early nuclear antigen was used in an indirect immunoperoxidase (IPA) staining procedure performed directly on acetone-fixed cell monolayers in standard tubes (16 by 125 mm). Of 190 clinical specimens tested, 30 specimens produced CMV cytopathic effect in tissue culture (TC-CPE) within 14 days after inoculation and, of these 30, 28 were positive for CMV after 48 h by the IPA staining procedure (sensitivity, 93%). Of the remaining 160 clinical specimens negative by TC-CPE within 14 days, 7 were positive by the IPA stain (specificity, 96%). However, three of these seven specimens were positive by TC-CPE upon subculture after the initial 14-day incubation period, and one specimen was overgrown by herpes simplex virus type 2 before CMV cytopathic effect could develop. The mean time to appearance of cytopathic effect for the 30 specimens positive by TC-CPE within 14 days was 6.7 days. These findings indicate that this IPA staining is a useful method for the rapid detection of CMV in cell monolayers inoculated with clinical specimens.