A comparative study of immunohistochemical methods for detecting abnormal prion protein with monoclonal and polyclonal antibodies

Transmissible spongiform encephalopathies are associated with the accumulat ion of abnormal prion protein (PrPSc) in the central nervous system which c an be detected immunohistochemically. Using a monoclonal antibody (L42) to an epitope on the first alpha-helix of ruminant PrP, we compared previously reported immunohistochemical antigen unmasking and "visualization" systems . Tn addition, a variety of polyclonal and monoclonal antibodies to other e pitopes:on ruminant PrP were assessed. Antigen unmasking by hydrated autocl aving and proteinase K treatments, and antigen detection with L42 and an av idin-biotin complex system, enabled intra- and extra-neuronal PrPSc:to be d emonstrated in scrapie-affected sheep carrying three different PrP alleles, as well as in cases of bovine spongiform encephalopathy. (C) 2000 Harcourt Publishers Ltd.