Figure 5. Comparison of protease-resistant PrPres from moose (Alces alces) with chronic wasting disease and from sheep with scrapie, Europe. Representative blots show epitope mapping analysis of PrPres (lane 4, CH1641; lane 5, moose no. 1; lane 6, moose no. 2) in comparison with different ovine transmissible spongiform encephalopathy isolates (lane 1, atypical/Nor98; lane 2, classical scrapie; and lane 3, CH1641). A chronic wasting disease isolate from Canada was loaded as control (lane 7). The antibodies used are indicated on the left. Protein standards are shown in lane M (10, 15, 20, 25, 37, and 50 kDa). The small amount of PrPres with intact 12B2 epitope in moose no.1 had a molecular weight higher than that observed with more C-terminal monoclonal antibodies (18.7 +0.3 kDa measured with 12B2 vs. 17.2 +0.1 kDa measured with L42). Even if the increase of the apparent molecular weight might be a known behavior when proteinase K cleavage occurs near the epitope, we noted that, in the case of moose no. 1, the 12B2-positive PrPres had a molecular weight higher than scrapie (18.1 +0.1 kDa measured with 12B2) and CH1641-like sample (18.1 +0.4 kDa when detected with 12B2). PrPres, protease-resistant core of abnormal form of prion protein.