FIG. 2.

(Top) Time from inoculation until severe clinical disease in NSE-HaPrP/MoPrP(−/−) and Tg7-HaPrP/MoPrP(−/−) transgenic mice infected with hamster scrapie strain 263K by the i.c., oral, and i.p. routes. The doses used were 1 × 10⁷ i.c. LD₅₀ for the i.c. and i.p. routes and 2 × 10⁸ i.c. LD₅₀ for the oral route. (Bottom) Effect of splenectomy on the susceptibility of transgenic mice to i.p. infection with 10⁷ i.c. LD₅₀ of hamster scrapie strain 263K. Splenectomy was done 10 to 14 days prior to scrapie infection.