Optimizing the real-time prion inactivation assay to quantify humic acid inactivation of CWD prions

Chronic Wasting Disease (CWD) is a transmissible spongiform encephalopathy (TSE) affecting the Cervidae family. Transmission of CWD largely occurs horizontally, following exposure to excreted or secreted infectious prions. A concerning aspect of CWD transmission is infection via indirect routes. Urine, saliva, feces, blood and carcasses of infected animals containing PrPCWD can persist in the environment for years and remain bioavailable. Humic acids, major components of soil organic matter, were shown via western blot to reduce the amount of CWD prions (Kuznetsova et al. 2018). We are developing a prion inactivation assay to quantify the efficacy of humic acid in reducing prion infectivity. Our work looks to optimize the assay and prion purification protocol to ensure that the fluorescent dye thioflavin T accurately detects reductions in infectious prion content following humic acid treatment. Our preliminary data shows that the assay is sensitive to small changes in infectious prion content and is a promising candidate for future use.