Pre-symptomatic detection of prions by cyclic amplification of protein misfolding

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders affecting humans and animals. At present, it is not possible to recognize individuals incubating the disease before the clinical symptoms appear. We investigated the effectiveness of the "Protein Misfolding Cyclic Amplification" (PMCA) technology to detect the protease-resistance disease-associated prion protein (PrPres) in pre-symptomatic stages. PMCA allowed detection of PrPres in the brain of pre-symptomatic hamsters, enabling a clear identification of infected animals as early as two weeks after inoculation. Furthermore, PMCA was able to amplify minute quantities of PrPres from a variety of experimental and natural TSEs. Finally, PMCA allowed the demonstration of PrPres in an experimentally infected cow 32 month post-inoculation, that did not show clinical signs and was negative by standard Western blot analysis. Our findings indicate that PMCA may be useful for the development of an ultra-sensitive diagnostic test to minimize the risk of further propagation of TSEs. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.