PAD-Beads enrichment enhances detection of PrP(Sc) using real-time quaking-induced conversion

OBJECTIVE: Scrapie is a transmissible spongiform encephalopathy (TSE) that naturally occurs in sheep and goats. This fatal neurodegenerative disease results from misfolding of the normal cellular prion protein (PrP(C)) to a pathogenic prion protein form (PrP(Sc)). This pathogenic form, PrP(Sc), accumulates in the brain and lymphoid tissues. The presence of PrP(Sc) can be detected by an in vitro conversion assay known as real-time quaking induced conversion (RT-QuIC). RT-QuIC has been used to detect PrP(Sc) in a variety of biological tissues from brains to fluids. While this technique is both rapid and sensitive, enhancing the detection of prions would be valuable in the diagnostic laboratories. RESULTS: In this study, we assessed whether PrP(Sc) detection sensitivity of RT-QuIC can be increased by enriching PrP(Sc) in scrapie tissue homogenates using commercially available aggregated protein binding ligands coated magnetic beads (PAD-Beads). Coupling of RT-QuIC to PAD-Beads based cleanup allowed detection of PrP(Sc) rapidly and without dilution of scrapie sheep brain homogenates prior to RT-QuIC. The PAD-Beads sample pretreatment step prior to RT-QuIC is a useful enhancement in the diagnosis of TSEs.