Characterization of BSE and scrapie strains/isolates
Following the BSE epidemic in cattle and the emergence of a variant form of Creutzfeldt-Jakob disease in humans, the question was raised whether BSE has been transmitted to small ruminants by the inadvertent feeding of infectious meat and bone meal. Such infections could easily be conceiled in countries where scrapie is endemic. To address this issue by immuno-chemically analyzing the PrPSc fragments, we have developed two lines of research. Firstly we have focused on the development of criteria for the differential characterization of experimental BSE and scrapie strains/isolates in rodents. To date, three criteria have been identified: quantification of the relative banding intensities of PrPSc glycotypes using a photoimaging technique; the non-uniform kinetic of proteinase K degradation of PrPSc; and differences in the molecular masses of their nongly cosylated PrPSc fragments after PK cleavage in immunoblot. The second line of research focused on the implementation of the criteria described above to representative samples from scrapie diseased Irish sheep. Using these three criteria, no evidence was found for the presence of a BSE infection in these animals. However, the final conclusion must take into account the results of mouse incubation time and mouse lesion profile data which are currently being generated.
KeywordsPrion Protein Bovine Spongiform Encephalopathy Scrapie Strain Prpsc Type Scrapie Case
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