PRNP and Creutzfeldt Jacob disease: In summary, Western blotting using a range of relevant anti-PrP antibodies (to detect different PrPres fragments) and two different sample enrichment methods (to increase PrPres detection sensitivity) failed to produce evidence of PrPres in these cases, similar to that which is found in CJD, sFI, FFI or VPSPr (Figures 4,5 and6).