In Vitro Detection of prionemia in TSE-Infected Cervids and Hamsters

Abstract

Blood-borne transmission of infectious prions during the symptomatic and asymptomatic stages of disease occurs for both human and animal transmissible spongiform encephalopathies (TSEs). The geographical distribution of the cervid TSE, chronic wasting disease (CWD), continues to spread across North America and the prospective number of individuals harboring an asymptomatic infection of human variant Creutzfeldt-Jakob Disease (vCJD) in the United Kingdom has been projected to be ~1 in 3000 residents. Thus, it is important to monitor cervid and human blood products to ensure herd health and human safety. Current methods for detecting blood-associated prions rely primarily upon bioassay in laboratory animals. While bioassay provides high sensitivity and specificity, it requires many months, animals, and it is costly. Here we report modification of the real time quaking-induced conversion (RT-QuIC) assay to detect blood-borne prions in whole blood from prion-infected preclinical white-tailed deer, muntjac deer, and Syrian hamsters, attaining sensitivity of >90% while maintaining 100% specificity. Our results indicate that RT-QuIC methodology as modified can provide consistent and reliable detection of blood-borne prions in preclinical and symptomatic stages of two animal TSEs, offering promise for prionemia detection in other species, including humans.

Factors intrinsic and extrinsic to blood hamper the development of a routine blood test for human prion diseases

“…The RT-QuIC assay was shown to be applicable for the detection of PrP TSE in the whole blood of CWD-infected cervids and TME-infected hamsters, during both the preclinical and clinical phases of the disease, with approximately 94 % sensitivity and 100 % specificity (Elder et al, 2013). Moreover, it has been shown that limited cycles of freeze-thawing of the blood samples enhances the sensitivity of blood-borne prion detection by RT-QuIC during the preclinical phase of the disease (Elder et al, 2013).…”

“…The RT-QuIC assay was shown to be applicable for the detection of PrP TSE in the whole blood of CWD-infected cervids and TME-infected hamsters, during both the preclinical and clinical phases of the disease, with approximately 94 % sensitivity and 100 % specificity (Elder et al, 2013). Moreover, it has been shown that limited cycles of freeze-thawing of the blood samples enhances the sensitivity of blood-borne prion detection by RT-QuIC during the preclinical phase of the disease (Elder et al, 2013). This increased sensitivity may be due to the damaging effect of the thermal shock on the membranes of infected blood cells, which releases the intracellular components, including prions, thus increasing the in vitro nucleation and consequently the detection of PrP Cconverting activity (Elder et al, 2013).…”

“…Moreover, it has been shown that limited cycles of freeze-thawing of the blood samples enhances the sensitivity of blood-borne prion detection by RT-QuIC during the preclinical phase of the disease (Elder et al, 2013). This increased sensitivity may be due to the damaging effect of the thermal shock on the membranes of infected blood cells, which releases the intracellular components, including prions, thus increasing the in vitro nucleation and consequently the detection of PrP Cconverting activity (Elder et al, 2013).…”

In utero transmission and tissue distribution of chronic wasting disease-associated prions in free-ranging Rocky Mountain elk

“…In some infected populations, CWD is a leading cause of cervid mortality and may negatively impact population dynamics (Dulberger et al, 2010;Sargeant et al, 2011). Both clinically and preclinically infected cervids harbour sufficient infectious prions to efficiently transmit disease (Hill & Collinge, 2003;Bishop et al, 2013;Elder et al, 2013). CWD can be transmitted by direct contact with infected animals, carcasses, bodily fluids, secretions or excreta (Mathiason et al, 2006;Saunders et al, 2012;Lacroux et al, 2014), or indirectly through uptake of infectious material shed into the environment (Miller & Williams, 2004;Mathiason et al, 2006;Saunders et al, 2012).…”

First Demonstration of Transmissible Spongiform Encephalopathy-associated Prion Protein (PrPTSE) in Extracellular Vesicles from Plasma of Mice Infected with Mouse-adapted Variant Creutzfeldt-Jakob Disease by in Vitro Amplification

“…PrP TSE has been successfully detected in the following: in whole blood of experimentally infected mice and hamsters, in sheep with natural scrapie and experimental BSE, and in white-tailed deer afflicted with CWD (21)(22)(23); in buffy coats of hamsters and sheep experimentally infected with scrapie (24 -26), as well as in plasma of mice and hamsters with scrapie; and in sheep and white-tailed deer naturally and experimentally infected with scrapie and CWD, respectively (27)(28)(29)(30). However, it is still not fully understood in what blood component TSE infectivity and/or PrP TSE reside and whether and how blood contributes to the spread of the disease from the periphery to the brain.…”