Comparison of human cytomegalovirus growth in MRC-5 human fibroblasts, brain, and choroid plexus cells in vitro.

Cell cultures derived from human brain, choroid plexus, and human lung fibroblasts (MRC-5) were infected with the Towne strain of human cytomegalovirus (CMV). The cytopathic effect, beginning 24-48 hours after infection, was characterized by foci of enlarged rounded cells that spread slowly and eventually coalesced to destroy the entire monolayer within one week. Cowdry type A inclusion bodies and herpes virus nucleocapsids were seen in infected cells. CMV-specific antigen was demonstrated by immunofluorescence in fibroblasts and astrocytic cells of brain cultures and in cells of choroid plexus cultures as well as in MRC-5 fibroblasts. Despite these morphologic and immunochemical similarities the growth of CMV differed in cells of brain and choroid plexus origin as compared with MRC-5 cells. In brain and choroid plexus cell cultures most of the virus remained cell-associated throughout the observation period of one week, whereas in MRC-5 cells the CMV was found in both cell-associated and cell-free fractions of harvested material.