Retrospective analysis of sheep scrapie by western blotting with formalin-fixed paraffin-embedded (FFPE) tissues.

An abnormal isoform of prion protein (PrP(Sc)) was extracted from formalin-fixed paraffin-embedded (FFPE) tissues from sheep and analyzed by western blotting. PrP(Sc) immunoreactivity against anti-PrP monoclonal antibody T2, which recognizes discontinuous PrP sequences, differed amongst individual scrapie sheep cases. This may reflect structural differences in PrP(Sc) that have been formalin-fixed prior to their extraction. This study indicates that western blotting by using FFPE tissues is useful for the retrospective analysis of transmissible spongiform encephalopathies in which only formalin-fixed samples are available and in conducting transmissible spongiform encephalopathies surveillance where freezing system is insufficient.