[Infectious activity of cell fractions isolated from the brain of mice with scrapie].

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.