Comparison of in situ DNA hybridization and immunological staining with conventional virus isolation for the detection of human cytomegalovirus infection in cell cultures

The sensitivity of immunochemical staining and in situ DNA hybridization for the detection of human cytomegalovirus (HCMV) was compared with that of virus isolation. Human diploid fibroblasts were infected with serial, 10-fold dilutions of HCMV strain AD169 and examined at various intervals between 1 and 42 days after inoculation, using the three methods being compared. HCMV-DNA was detected by in situ hybridization using a biotin-labeled HCMV probe and CMV early antigen (EA) by immunochemistry using a specific monoclonal antibody. During the first 2 days after inoculation detection of EA appeared to be the most sensitive method. After the fifth day the sensitivity of the immunochemical and in situ hybridization methods was similar and equalled that of conventional virus isolation. However, 2-5 times more HCMV-DNA than HCMV-EA positive cells were detected. Our results indicate that both detection of HCMV-EA by immunological staining and HCMV-DNA by in situ hybridization are suitable methods for rapid and sensitive detection of HCMV infections.