Figure 2. Biochemical characterization of the prion protein (PrPSc) associated with ARR/ARR cases in France and Germany. A) Western blot (stained by monoclonal antibody L42) illustrating that protein kinase (PK)– treated ovine bovine spongiform encephalopathy (BSE) PrPSc has ≈1-kDa lower molecular mass than PrPSc from the scrapie cases. Lane 1, S115/04, molecular mass (MM) 20.95 kDa; lane 2, S83, MM 19.96 kDa; lane 3, S95 classic scrapie, MM 19.64 kDa; lane 4, ovine BSE, MM 18.85 kDa. B) PrPSc PK sensitivity measured by using brain from S83 scrapie case (▲), ARR/ARR BSE in sheep (○), ARQ/ARQ BSE in sheep (●), BSE from bovines (■), an ARR/ARR atypical scrapie case (▼), and 20 randomly selected isolates from sheep with scrapie in France (2 cases shown, represented as □ and ◆). PrPSc ELISA measurements were performed by using the TeSeE Sheep/Goat rapid test (Bio-Rad) after brain homogenate digestion using a PK concentration ranging from 50 µg/mL to 500 µg/mL. Three tests were performed for each sample and PK concentration.