Immunoblotting of Creutzfeldt-Jakob disease prion proteins: host species-specific epitopes.

Creutzfeldt-Jakob disease (CJD) is a rare dementia that is generally found in older people and is caused by unusual infectious pathogens or prions. Using rabbit antisera raised against hamster scrapie prion proteins (HaPrPSc), we identified by immunoblotting human CJD prion proteins (HuPrPCJD) in the brains of 14 patients dying of CJD. Extracts from 6 of the patients were transmitted to mice after prolonged incubation. The rabbit antisera raised against HaPrPSc also reacted with the mouse CJD prion proteins (MoPrPCJD) found in the brains of these experimentally infected mice. When mice were immunized with HuPrPCJD, they produced antibodies that reacted with HuPrPCJD but not with MoPrPCJD. Mice immunized with MoPrPCJD produced antibodies to neither murine nor human prion proteins. Our results provide evidence for host species-specific epitopes on prion proteins. The existence of such epitopes is consistent with the apparent lack of an immune response during prion infections and the finding that prion protein molecules are encoded by host genes.