Figure 6: PK-resistant PrP C-terminal fragments (PrP-CTF12/13). (A) Detection of PrPCTF12/13 in vCJD and sCJD by Western blotting with anti-C antibody against human PrP220-231. While the PrP-CTF12/13 fragments were detectable in all three sCJD cases, they were undetectable in all three vCJD (see dotted line rectangle). (B) Western blot analysis of PrPCTF12/13 in iCJD and sCJD. All three sCJD cases exhibited PrP-CTF12/13. In contrast, only one out of three iCJD had PrP-CTF12/13 (dotted line rectangle). (C) Western blot analysis of PrP-CTF12/13 inPrPSc from sCJD or iCJD, after treatment with PK and PNGase F (dotted line rectangle), confirmed the absence of PrP-CTF12/13 fragments.