Prolonged infection of mouse brain neurons with murine cytomegalovirus after pre- and perinatal infection

The susceptibility of mice at different developmental stages to a relatively low titer of cell culture-passaged murine cytomegalovirus (MCMV) infection was compared in terms of the urinary excretion of MCMV examined by plaque assay and in terms of the distribution of viral infection, determined by immunohistochemistry, using antibodies specific to the early nuclear antigen of MCMV. Viral infection on day 8.5 of gestation (E8.5) into the conceptus and intraperitoneal infection on day 15.5 of gestation (E15.5), postnatal day 2 (P2), postnatal day 11 (P11), and 30 days after birth (P30), respectively, were performed. Embryonal and perinatal mice were more susceptible to MCMV in terms of urinary excretion of the virus and the presence of viral antigen-positive cells in the brain, lungs, and kidneys. In the embryonal and perinatal infection, the viral antigen-positive cells in the neurons of the cerebral cortex and hippocampus were retained late after birth, even though the positive cells in the lungs and kidneys had disappeared. In the mice infected on E8.5, small clusters of viral antigen-positive cells were detected only in the cortex and hippocampus late after birth, without the urinary excretion of virus. These results suggest that when mice are infected with MCMV at the embryonal and perinatal stages, elimination of the infected neurons is delayed compared with that of the other cells in the lungs and kidneys. These findings provide a model for the analysis of pathogenesis of the subclinical congenital CMV infection that manifested clinically late after birth in humans as brain disorders.

The status of CMV as a human pathogen

Cytomegalovirus (CMV) is a common infectious agent which is well adapted to its host. Following primary infection, which is almost always asymptomatic in people with normal immunity, the virus establishes latency at sites which are unknown. The virus is probably maintained in this latent state by immune surveillance mechanisms since immunosuppression frequently leads to reactivation of virus.

Cytomegalovirus has been identified in most anatomical areas of the human body. The aim of this article is to define criteria for pathogenicity so that clinical and experimental data can be reviewed to determine if CMV is likely to cause disease at these various clinical sites. Thus, patients have been shown to die frequentlywithCMV but do they diefromit?

Glomerulonephritis caused by murine cytomegalovirus. Potentiation by antithymocyte serum

Murine cytomegalovirus was found to be highly nephrotropic in mice treated with antithymocyte serum. The earliest histologic change was characteristic intranuclear inclusions in the glomerular endothelial cells. This change was followed by an eosinophilic thickening of the glomerular capillary loops. In later stages, proliferation of capsular epithelial cells and glomerular sclerosis was prominent. Tubular casts were present, and perivascular lymphoid aggregations were seen in the medulla and juxtamedullary section 56 days after inoculation. No conspicuous lesions occurred in uninfected mice treated with antithymocyte serum or in untreated infected mice. The possible mechanisms of the renal lesions are discussed.