For prion protein detection, deparaffinization and hydration of tissue sections was performed manually using Pro-Par solvent and graded alcohols to distilled water. Antigen retrieval was accomplished using a Biocare Medical DC2002 Decloaking Chamber and Citrate Buffer pH 6.0 (0.01 M), ~ 20 min at 120 °C and 20 PSI. For staining of prion protein, a biotinylated monoclonal anti-prion antibody 3F4 (Covance Research Products) was used at a 1:50 dilution in antibody dilution buffer (Ventana ADB250), and applied for 60 min at 37 °C followed by detection using a DABMap detection kit and hematoxylin counterstain. Staining was performed on the automated Discovery XT staining system (Ventana Medical Systems).