Western Immunoblot Mapping of a Swedish Case of NOR98

Nor98 is an atypical form of sheep scrapie, which recently has been identified in 5 cases in Sweden. These cases are the first recorded animal TSEs in Sweden since 1988. Nor98 was first described in Norway in 1998 and differs from classical scrapie in several features, among others, its epidemiology and proteolytic profile of the pathological prion protein. We have extracted Nor98 prion from brain suspensions of affected sheep and mapped the proteinase K-resistant fragment by immunoblotting, using various anti-prion antibodies. In brain material extracted from Nor98 case a proteinase-resistant fragment around 10 kDa was demonstrated. This fragment has its N-terminal end between amino acid residue 40 to 93, and its C-terminal end around amino acid residue 145. In addition, a proteinase-resistant fragment of around 19 kDa (after glycosylation9 could be detected by Mab 6H4, but not by Mab P4. This complex fragmental pattern after proteinase K treatment suggested that the prion protein in the brain of sheep affected by Nor98 exists in several conformational forms