Effect of Sinc genotype, agent isolate and route of infection on the accumulation of protease-resistant PrP in non-central nervous system tissues during the development of murine scrapie

Mice congenic for the Sinc gene were infected intracerebrally with two scrapie strains, ME7 and 22A. At various times during the incubation period tissues were monitored for the infection-specific form of PrP (PrP(Sc)). PrP(Sc) was found in brain, spleen, lymph nodes, pancreas, submaxillary gland and thymus. After intraperitoneal inoculation PrP(Sc) was found in spleen, lymph nodes, pancreas and submaxillary glands prior to its detection in brain. The kinetics of accumulation of PrP(Sc) in these tissues was dependent on the infecting strain of agent, on the mouse Sinc genotype and on the route of infection. This study supports using the presence of PrP(Sc) as an indicator of infectivity in brain and extraneural tissues and defines some of the parameters which influence when and where PrP(Sc) is first found.