Newer biochemical and pathobiochemical knowledge in the genesis, development and prevention of scrapie

Scrapie is induced by transformation of instable prion proteins (PrPC) into stable, proteaseresistent prion proteins (PrPSC). The accumulation of PrPS C in nerve cells elicits a destruction and vacuolation; a spongiform enceph alopathy develops. There exist more than 50 different types of priongen-all eles, that code a different amino acid sequence in the prion proteins. The PrPSC are resorbed in the peyer plaques of the ileum into the mucosa. Then the infection spreads into the lymphatic and nervous tissue of the gastro-i ntestinal tract. By the N. vagus the formation of PrPSC reaches the brain a nd by vegetative ganglions the spinal marrow. Scrapie can be prevented by b reeding of sheep with certain types of prion gens.