Detection of typical and atypical bovine spongiform encephalopathy and scrapie prion strains by prion protein motif-grafted antibodies.

To evaluate further the reactivity of prion-specific monoclonal antibodies containing the 89-112 or 136-158 prion protein (PrP) polypeptides, immunoprecipitations were performed on brain extracts from Italian bovines, sheep and goats with transmissible spongiform encephalopathies. No binding of IgG 89-112 or IgG 136-158 to PrP in normal brain extracts was detected. Conversely, both reagents immunoprecipitated PrP from bovine and bovine amyloidotic spongiform encephalopathies, and from typical and atypical scrapie brain extracts. The immunoprecipitated PrP bands mirrored the Western blot (WB) profile of the different prion strains, indicating universal affinity of two independent PrP regions for disease-associated PrP conformers regardless of species source and strain properties. Immunoprecipitation with motif-grafted antibodies increased the sensitivity of conventional detection methods based on centrifugation followed by WB, which was confirmed by assay of diluted samples using both methods. These reagents or derivative molecules may thus find broad applications in prion detection and research.