In vitro amplification of PrP(Sc) derived from the brain and blood of sheep infected with scrapie

• Published in: Journal of general virology Vol. 89; pp. 3177 - 3184
• Main Authors: Thorne, Leigh, Terry, Linda A
• Format: Journal Article
• Language: English
• Published: 2008
• Subjects: blood; brain; protein misfolding cyclic amplification; PrPSc proteins; scrapie; sheep
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.2008/004226-0

Scrapie is a fatal, naturally transmissible, neurodegenerative prion disease that affects sheep and goats and is characterized by the accumulation of a misfolded protein, PrP(Sc), converted from host-encoded PrP(c), in the central nervous system of affected animals. Highly efficient in vitro conversion of host PrP(c) to PrP(Sc) has been achieved in models of scrapie and in natural prion diseases by protein misfolding cyclic amplification (PMCA). Here, we demonstrate amplification, by serial PMCA, of PrP(Sc) from individual sources of scrapie-infected sheep. Efficiency of amplification was affected by the pairing of the source of PrP(Sc) with the control brain substrate of different genotypes of PrP. In line with previous studies, efficiency of amplification was greatly enhanced with the addition of a synthetic polyanion, polyadenylic acid (PolyA), facilitating rapid detection of low levels of PrP(Sc) from body fluids such as blood. To this end PrP(Sc) was amplified, in a 3 day PMCA assay, from blood leukocyte preparations from VRQ/VRQ scrapie-affected sheep at clinical end point. While PolyA-assisted PMCA resulted in spontaneous conversion of PrP(c), we were able to distinguish blood samples from unaffected and affected sheep under controlled conditions. This study demonstrates that highly efficient amplification of PrP(Sc) can be achieved for ovine scrapie from both brain and blood from naturally infected sheep and shows potential applications for improvements in current diagnostics and pre-mortem testing.