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[Infectious activity of cell fractions isolated from the brain of mice with scrapie]
Abstract:
The agent of scrapie was found to induce clinically similar diseases in BALB/c and NIH mice but differing in the duration of the incubation period (155-180 days and 110-140 days, respectively) and pathomorphological manifestations. Differentiated examinations of a brain cell pool from mice with scrapie revealed more infectious activity not neutralized with nucleases and pronasa in membrane-free cell fractions than in fractions of slowly sedimenting membranes.
Insights
Scrapie disease in mice shows varied incubation periods and brain changes. Infectious activity in scrapie-infected mouse brain cells is concentrated in membrane-free fractions, unaffected by nucleases or pronase.
Area of Science:
- Neuroscience
- Virology
- Pathology
Background:
- Scrapie is a transmissible spongiform encephalopathy affecting the central nervous system.
- Understanding the pathogenesis of scrapie is crucial for developing diagnostic and therapeutic strategies.
Purpose of the Study:
- To investigate the clinical and pathological differences in scrapie infection between BALB/c and NIH mice.
- To characterize the distribution and properties of the infectious agent within brain cells.
Main Methods:
- Inoculation of BALB/c and NIH mice with the scrapie agent.
- Monitoring of clinical signs and incubation periods.
- Biochemical fractionation of infected mouse brain homogenates.
- Nuclease and pronase treatment of cell fractions to assess infectivity.
Main Results:
- Scrapie induced clinically similar diseases in both mouse strains, but with distinct incubation periods (BALB/c: 155-180 days; NIH: 110-140 days) and varied pathomorphological changes.
- Higher infectious activity was detected in membrane-free cell fractions compared to slowly sedimenting membrane fractions.
- The infectious activity in these fractions was resistant to neutralization by nucleases and pronase.
Conclusions:
- Mouse strain influences scrapie incubation period and neuropathology.
- The scrapie agent is predominantly localized in non-membranous cellular components of the brain.
- The infectious agent's resistance to enzymatic degradation suggests a non-nucleic acid or protein-protected nature.