Ultrastructural pathology of murine cytomegalovirus infection in cultured mouse nervous system tissue.

Mouse spinal cord-ganglia cultures were innoculated with murine cytomegalo-virus 14 days after explantation. Intranuclear virus was first observed 4 days after infection. The viruses, which occurred in four forms, were observed in increasing numbers during the ensuing 4 days. Differences were noted in the relative prevalence of certain of these forms in older as compared to younger cultures. This suggests that variations in virus form are related to virus maturation. Cytoplasmic viruses were occasionally observed, but their site of origin is not certain. A variety of cytoplasmic inclusions were seen, particularly in the older cultures. It seems likely that they represent specific cell responses to the presence of the virus. They were not observed in the control cultures, even though some of the latter did show severe degenerative changes.