Heterogeneous morphologic features of plaques induced by five strains of human cytomegalovirus.

Five strains of human cytomegalovirus (CMV) were examined in three human fibroblastic cultural systems with respect to plaque size and morphologic features. Plaques produced in cultures of fibroblastic cells from thyroid, and to a lesser extent in those from human embryonic skin-muscle tissue, had strain-associated morphologic differences that were stable on repetitive examination. The variations in morphologic characteristics of plaques appeared to reflect cytopathic changes, and the five strains could be separated on the basis of morphologic characteristics into two polar groups. Comparison of the sensitivities of three human fibroblastic cell lines for the detection of CMV revealed that one line was consistently inferior.