A monoclonal antibody that enables specific immunohistological detection of prion protein in bovine spongiform encephalopathy cases.

The specificity of a monoclonal antibody (mAB) raised against recombinant bovine prion protein (PrP) for the immunohistological detection of PrP accumulation in the medulla oblongata of bovine spongiform encephalopathy (BSE) and ovine scrapie cases was investigated. mAB KG9 showed a diffuse low intensity reaction with the cytoplasm of neurones in normal cattle and sheep sections. In BSE sections the mAB detected widespread granular deposits of PrP associated with neurones and the neuropil. Although scrapie sections showed similar levels of granular deposits with another antibody to PrP these were not detected by KG9 which did however detect diffuse staining in neuronal cytoplasm. Possible explanations for the specificity of binding of KG9 are discussed.