Cross-sequence transmission of sporadic Creutzfeldt-Jakob disease creates a new prion strain

The genotype ( methionine or valine) at polymorphic codon 129 of the human prion protein (PrP) gene and the type ( type 1 or type 2) of abnormal isoform of PrP ( PrPSc) are major determinants of the clinicopathological phenotypes of sporadic Creutzfeldt-Jakob disease (sCJD). Here we found that the transmission of sCJD prions from a patient with valine homozygosity (129V/V) and type 2 PrPSc (sCJD-VV2 prions) to mice expressing human PrP with methionine homozygosity (129M/M) generated unusual PrPSc intermediate in size between type 1 and type 2. The intermediate type PrPSc was seen in all examined dura mater graft-associated CJD cases with 129M/M and plaque-type PrP deposits (p-dCJD). p-dCJD prions and sCJD-VV2 prions exhibited similar transmissibility and neuropathology, and the identical type of PrPSc when inoculated into PrP-humanized mice with 129M/M or 129V/V. These findings suggest that p-dCJD could be caused by cross-sequence transmission of sCJD-VV2 prions.