Location: Virus and Prion ResearchTitle: RT-QuIC seeding activity using elk recombinant prion proteins discriminates scrapie isolates Author
Submitted to: Prion
Publication Type: Abstract Only
Publication Acceptance Date: 4/22/2018
Publication Date: 5/22/2018
Citation: Hwang, S., Greenlee, J.J., Vance, N.M., Nicholson, E.M. 2018. RT-QuIC seeding activity using elk recombinant prion proteins discriminates scrapie isolates. Prion 2018. Poster No. P58, p. 85.
Technical Abstract: Aims: Prions are amyloid-forming proteins that cause transmissible spongiform encephalopathies through a process involving conversion from the normal cellular prion protein (PrPC) to the pathogenic misfolded conformation (PrPSc). This conversion has been used for in vitro assays including serial protein misfolding amplification and real-time quaking induced conversion (RT-QuIC). RT-QuIC has been used for the detection of prions in a variety of biological tissues from humans and animals. Extensive work has been done to demonstrate that RT-QuIC is a rapid, specific, and highly sensitive prion detection assay. RT-QuIC uses recombinant prion protein to detect minute amounts of PrPSc. RT-QuIC has been successfully used for the detection of prions and for strain discrimination in a variety of biological tissues from humans and animals. However, RT-QuIC has not been shown to be useful to detect or discriminate different genotypes of sheep scrapie with recombinant elk prion proteins. Methods: To do this, we used RT-QuIC assay as a measure of prion seeding activity. Elk recombinant prion protein was seeded with brain tissue samples from different strains and different genotypes of sheep infected with scrapie. We also inoculated transgenic mice expressing M132 elk PRNP (Tg12) with scrapie from different genotypes of sheep to compare with our RT-QuIC results. Results: We found that reaction mixtures seeded with genotype VRQ/VRQ sheep brains have better conversion efficiency with elk substrate M132 compared to reactions seeded with the genotype ARQ/ARQ sheep brains regardless of strain types used. Our bioassay data also supported RT-QuIC results showing significantly shorter incubation period for inoculum from VRQ/VRQ sheep when compared to inoculum from ARQ/ARQ sheep. Conclusions: Therefore, we conclude that genotypic background of both source and recipient can strongly influence susceptibility, so pooled inocula historically used in the prion transmission studies may make drawing concrete conclusions regarding strains difficult.