Monoclonal Antibody against a Peptide of Human Prion Protein Discriminates between Creutzfeldt-Jacob's Disease-affected and Normal Brain Tissue

Abstract Current methods for diagnosing transmissible spongiform encephalopathies rely on the degradation of the cellular prion protein (PrPC) and the subsequent detection of the protease-resistant remnant of the pathological prion isoform PrPSc by antibodies that react with all forms of PrP. We report on a monoclonal antibody, V5B2, raised against a peptide from the C-terminal part of PrP, which recognizes an epitope specific to PrPSc. In cryostat sections from Creutzfeldt-Jacob's disease (CJD) patients' brains, V5B2 selectively labels various deposits of PrPSc without any pretreatment for removal of PrPC. V5B2 does not bind to non-CJD brain samples or to recombinant PrP, either in its native or denatured form. Specificity for PrP is confirmed by a sandwich enzyme-linked immunosorbent assay utilizing V5B2, which discriminates between CJD and normal samples without proteinase K treatment, and by immunoprecipitation from CJD brain homogenate. The PrPSc-specific epitope is disrupted by denaturation. We conclude that the C-terminal part of PrP in disease-associated PrPSc aggregates forms a structural epitope whose conformation is distinct from that of PrPC.