Application of Prionics Western blotting procedure to screen for BSE in cattle regularly slaughtered at Swiss abattoirs

Disease-specific PrP (PrPSc) is at least part of the infectious particle (p rion) causing bovine spongiform encephalopathy (BSE) or scrapie in sheep Di gestion with protease allows a distinction between normal PrP (PrPC) and Pr PSc i.e. PrPC is completely digested while PrPSc is cleaved at the N-termin us leading to a fragment of reduced molecular weight (PrP 27-30). Detection of this fragment by Western blotting has been described more than a decade ago for rodent PrP. We have now optimized the technique in order to allow rapid analysis of hundreds of samples per day. Here we report the applicati on of this technique to the analysis of 3000 regularly slaughtered cattle f rom Swiss abattoirs. For comparison all the animals were subsequently exami ned by classical methods (i.e. histology and immunohistochemistry). All but one animal were negative for BSE by all methods. The Western blot positive animal was confirmed to be a BSE case and the carcass was removed from the food chain. We conclude that it is feasible to examine slaughtered cattle on a routine basis without causing delays to the meat processing industry.