The following prion isolates were tested: sCJD (three subtypes: MM1, MM2, and VV2); vCJD; sCJD(MM1) prions passaged in Tg mice expressing the M129 variant of human PrP [Tg(HuPrP) mice]; cattle BSE; elk CWD; sheep scrapie isolate SSBP/1; sCJD(MM1) prions passaged in guinea pigs; hamster-adapted scrapie strain Sc237; mouse-adapted scrapie strain RML; mouse-adapted BSE strain 301V [maintained in mice expressing either the PrP-A or PrP-B allotype of mouse PrP and denoted 301V(A) and 301V(B), respectively]; MV-adapted RML; and MV-adapted Sc237 prions. Here, PRNP is linked to scrapie.