Related Experiment Videos
Experimental panencephalitis induced in suckling mice by parainfluenza I (6/94) virus. III. Ultrastructural studies
Abstract:
Intracerebral inoculation of newborn mice with Parainfluenza I (6/94) virus produces a chronic panencephalitis. Electron microscopic studies were carried out over 125 days of the infection. Productive infection of choroidal and ependymal epithelial cells was seen from postinoculation days 2nd to the 8th. Fusion of adjacent choroid and ependymal cells resulted in giant cell formation. Completed virions were seen adsorbed to circulating macrophages and these cells replicated intracytoplasmic nucleocapsids. Neuronal infection was evident on the 3rd postinoculation day, was widespread by the 6th day postinoculation and persisted to the 35th day postinoculation. Nucleocapsid alignment and budding from neuronal plasma membranes was never seen. An initially intense mononuclear cell infiltrate subsided by the 35th day but residual inflammation persisted throughout the study. Late in the course of the infection, vacuolation of the neuropil and a periventricular and deep cerebral spongiform change was seen which could not be directly associated with local viral replication. These ultrastructural findings are correlated with prior light microscopic, virological and immunofluorescent studies of the infection and compared to other experimental models of myxovirus central nervous system infections.
Insights
Parainfluenza virus infection in mice causes chronic brain inflammation and neuronal damage. Electron microscopy reveals viral replication in various brain cells, leading to neurological changes.
Area of Science:
- Neurovirology
- Pathology
- Electron Microscopy
Background:
- Parainfluenza virus infections can cause central nervous system (CNS) disease.
- Chronic viral encephalitis models are crucial for understanding persistent neurological disorders.
Purpose of the Study:
- To investigate the ultrastructural changes in the mouse brain following intracerebral inoculation with Parainfluenza I (6/94) virus.
- To characterize the cellular tropism and replication cycle of the virus within the CNS.
Main Methods:
- Intracerebral inoculation of newborn mice with Parainfluenza I (6/94) virus.
- Serial electron microscopic examination of brain tissue over 125 days postinoculation.
- Correlation of ultrastructural findings with light microscopy, virology, and immunofluorescence data.
Main Results:
- Productive viral infection observed in choroidal and ependymal cells (days 2-8), leading to giant cell formation.
- Neuronal infection was evident from day 3, widespread by day 6, and persisted for 35 days.
- Viral replication occurred within macrophages, but nucleocapsid alignment and budding from neurons were not observed.
- Late-stage spongiform changes and neuropil vacuolation were noted, not directly linked to local viral replication.
Conclusions:
- Parainfluenza virus induces chronic panencephalitis with distinct cellular targets and replication patterns.
- The study provides detailed ultrastructural insights into viral pathogenesis in the CNS.
- Late-onset spongiform changes suggest complex host-virus interactions or indirect mechanisms in chronic neuroinflammation.