Biochemical Characteristics and PrPSc Distribution Pattern in the Brains of Cattle Experimentally Challenged with H-type and L-type Atypical BSE

Besides the classical form of bovine spongiform encephalopathy (BSE) that has been known for almost three decades, two atypical forms designated H-type and L-type BSE have recently been described. While the main diagnostic feature of these forms is the altered biochemical profile of the accumulated PrP(Sc), it was also observed in the initial analysis that L-type BSE displays a distribution pattern of the pathological prion protein (PrP(Sc)), which clearly differs from that observed in classical BSE (C-type). Most importantly, the obex region in the brainstem is not the region with the highest PrP(Sc) concentrations, but PrP(Sc) is spread more evenly throughout the entire brain. A similar distribution pattern has been revealed for H-type BSE by rapid test analysis. Based on these findings, we performed a more detailed Western blot study of the anatomical PrP(Sc) distribution pattern and the biochemical characteristics (molecular mass, glycoprofile as well as PK sensitivity) in ten different anatomical locations of the brain from cattle experimentally challenged with H- or L-type BSE, as compared to cattle challenged with C-type BSE. Results of this study revealed distinct differences in the PrP(Sc) deposition patterns between all three BSE forms, while the biochemical characteristics remained stable for each BSE type among all analysed brain areas.