Goat K222-PrP(C) polymorphic variant does not provide resistance to atypical scrapie in transgenic mice.

Host prion (PrP(C)) genotype is a major determinant for the susceptibility to prion diseases. The Q/K222-PrP(C) polymorphic variant provides goats and mice with high resistance against classical scrapie and bovine spongiform encephalopathy (BSE); yet its effect against atypical scrapie is unknown. Here, transgenic mice expressing the goat wild-type (wt) or the K222-PrP(C) variant were intracerebrally inoculated with several natural cases of atypical scrapie from sheep and goat and their susceptibility to the prion disease was determined. Goat wt and K222-PrP(C) transgenic mice were 100% susceptible to all the atypical scrapie isolates, showing similar survival times and almost identical disease phenotypes. The capacity of the K222-PrP(C) variant to replicate specifically the atypical scrapie strain as efficiently as the goat wt PrP(C), but not the classical scrapie or cattle-BSE as previously reported, further suggests the involvement of concrete areas of the host PrP(C) in the strain-dependent replication of prions.