Plasminogen binds to disease-associated prion protein of multiple species

The protein-only hypothesis states that the causative agent of transmissible spongiform encephalopathies is PrPSc, a conformer of the cellular protein PrPc. Therefore, reagents differentiating between PrPc and PrPSc could be diagnostically useful. Plasminogen, when immobilised onto magnetic beads, selectively precipitates PrPSc from mice with prion infected brains. We have shown that human plasminogen also precipitates PrPSc from brain homogenate of patients with sporadic Creutzfeldt-Jakob disease, as well as from sheep with scrapie and cows of various breeds with bovine spongiform encephalophathy (BSE). Our findings suggest that the binding of plasminogen to PrPSc could have diagnostic application.