Early interactions between human cytomegalovirus and cells.

Adsorption of cytomegalovirus (CMV) to human fibroblasts was not inhibited by preincubation with other herpes viruses (HSV-1, HSV-2, VZV). Transport of virus to the nucleus was studied using virus labelled with 3H-thymidine. Radioactivity was found in the nucleus 20 minutes after virus had been added to the cells. In order to assess the expression of the virus genome, synthesis of early (EA) and late (LA) antigens was studied. Assayed on permissive human lung fibroblasts, a plaque purified virus contained more EA inducing than both EA and LA inducing viral units. Since this was a consistent finding with virions of all densities, it seems to be an effect of viral dose rather than of virion density. Alternatively, LA-defectiveness is a virion property which does not vary with virion density.