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Studies on the pathogenicity of human-origin parainfluenza virus in the brain of mice
Abstract:
The pathogenicity of parainfluenza type 2 (croup-associated) virus known to cause infections of the respiratory tract in the early life of man was studied in the brain of mice. One- to 4-day-old sucklings and 4-week-old mice were inoculated intracerebrally with the virus. The virus multiplied in sucklings, but not in adults. Most mice inoculated intracerebrally with the virus appeared healthy. Histological examination showed minimum inflammatory changes, although moderate hydrocephalus developed in three of twenty-one sucklings by 6 weeks post-infection. Immunofluorescent study in sucklings showed viral antigens in ependymal lining cells and choroid plexus epithelium during the first two weeks, and parenchymal cells for more than two months. Virus specific antibody response was observed in adults, but not in sucklings. One interesting finding was that viral antigens persisted in six out of 11 suckling brains for one to two months.
Insights
Parainfluenza type 2 virus can infect young mice brains, causing persistent viral antigens and mild hydrocephalus. Adult mice showed an antibody response, but the virus did not multiply in their brains.
Area of Science:
- Virology
- Neuroscience
- Pediatric Infectious Diseases
Background:
- Parainfluenza type 2 virus is a common cause of respiratory infections in young children.
- The neurotropic potential and long-term effects of this virus, particularly in early-life infections, are not well understood.
Purpose of the Study:
- To investigate the pathogenicity of parainfluenza type 2 virus in the brains of young and adult mice.
- To determine viral replication, persistence, and host response following intracerebral inoculation.
Main Methods:
- Intracerebral inoculation of parainfluenza type 2 virus into 1- to 4-day-old suckling mice and 4-week-old adult mice.
- Monitoring for clinical signs, histological examination for inflammatory changes and hydrocephalus.
- Immunofluorescence assays to detect viral antigens in brain tissues.
- Serological testing for virus-specific antibody response.
Main Results:
- The virus replicated in suckling mice brains but not in adult mice brains.
- Viral antigens persisted in suckling mice brains for up to two months, primarily in ependymal and choroid plexus cells.
- Moderate hydrocephalus developed in a subset of infected sucklings.
- Adult mice developed a virus-specific antibody response, while sucklings did not.
Conclusions:
- Parainfluenza type 2 virus exhibits neurotropism in early-life infections, with potential for long-term viral antigen persistence in the brain.
- The findings suggest a differential host response between young and adult mice, with implications for understanding viral pathogenesis in the central nervous system.
- Further research is warranted to explore the clinical significance of persistent viral antigens and hydrocephalus in neonatally infected hosts.