| Summary: | <p>Abstract</p> <p>Background</p> <p>Protein misfolding cyclic amplification (PMCA) is a method that facilitates the detection of prions from many sources of transmissible spongiform encephalopathy (TSE). Sheep scrapie represents a unique diversity of prion disease agents in a range of susceptible <it>PRNP</it> genotypes. In this study PMCA was assessed on a range of Great Britain (GB) sheep scrapie isolates to determine the applicability to veterinary diagnosis of ovine TSE.</p> <p>Results</p> <p>PrP<sup>Sc</sup> amplification by protein misfolding cyclic amplification (PMCA) was assessed as a diagnostic tool for field cases of scrapie. The technique was initially applied to thirty-seven isolates of scrapie from diverse geographical locations around GB, and involved sheep of various breeds and <it>PRNP</it> genotypes. All samples were amplified in either VRQ and/or ARQ PrP<sup>C</sup> substrate. For PrP<sup>Sc</sup> from sheep with at least one VRQ allele, all samples amplified efficiently in VRQ PrP<sup>C</sup> but only PrP<sup>Sc</sup> from ARH/VRQ sheep amplified in both substrates. PrP<sup>Sc</sup> from ARQ/ARQ sheep displayed two amplification patterns, one that amplified in both substrates and one that only amplified in ARQ PrP<sup>C</sup>. These amplification patterns were consistent for a further 14/15 flock/farm mates of these sheep. Furthermore experimental scrapie strains SSBP1, Dawson, CH1641 and MRI were analysed. SSBP1 and Dawson (from VRQ/VRQ sheep) amplified in VRQ but not ARQ substrate. MRI scrapie (from ARQ/ARQ sheep) nor CH1641 did not amplify in ARQ or VRQ substrate; these strains required an enhanced PMCA method incorporating polyadenylic acid (poly(A)) to achieve amplification.</p> <p>Conclusions</p> <p>PrP<sup>sc</sup> from 52 classical scrapie GB field isolates amplified in VRQ or ARQ or both substrates and supports the use of PMCA as a rapid assay for the detection of a wide range of ovine classical scrapie infections involving multiple <it>PRNP</it> genotypes and scrapie strains.</p>
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