title: Prion-seeding activity in cerebrospinal fluid of deer with chronic wasting disease.
abstract: Transmissible spongiform encephalopathies (TSEs), or prion diseases, are a uniformly fatal family of neurodegenerative diseases in mammals that includes chronic wasting disease (CWD) of cervids. The early and ante-mortem identification of TSE-infected individuals using conventional western blotting or immunohistochemistry (IHC) has proven difficult, as the levels of infectious prions in readily obtainable samples, including blood and bodily fluids, are typically beyond the limits of detection. The development of amplification-based seeding assays has been instrumental in the detection of low levels of infectious prions in clinical samples. In the present study, we evaluated the cerebrospinal fluid (CSF) of CWD-exposed (n=44) and naïve (n=4) deer (n=48 total) for CWD prions (PrP(d)) using two amplification assays: serial protein misfolding cyclic amplification with polytetrafluoroethylene beads (sPMCAb) and real-time quaking induced conversion (RT-QuIC) employing a truncated Syrian hamster recombinant protein substrate. Samples were evaluated blindly in parallel with appropriate positive and negative controls. Results from amplification assays were compared to one another and to obex immunohistochemistry, and were correlated to available clinical histories including CWD inoculum source (e.g. saliva, blood), genotype, survival period, and duration of clinical signs. We found that both sPMCAb and RT-QuIC were capable of amplifying CWD prions from cervid CSF, and results correlated well with one another. Prion seeding activity in either assay was observed in approximately 50% of deer with PrP(d) detected by IHC in the obex region of the brain. Important predictors of amplification included duration of clinical signs and time of first tonsil biopsy positive results, and ultimately the levels of PrP(d) identified in the obex by IHC. Based on our findings, we expect that both sPMCAb and RT-QuIC may prove to be useful detection assays for the detection of prions in CSF.
authors.affiliation: Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Haley
authors.forename: Alexandra
authors.initials: A
authors.lastname: Van de Motter
authors.forename: Scott
authors.initials: S
authors.lastname: Carver
authors.forename: Davin
authors.initials: D
authors.lastname: Henderson
authors.forename: Kristen
authors.initials: K
authors.lastname: Davenport
authors.forename: Davis M
authors.initials: DM
authors.lastname: Seelig
authors.forename: Candace
authors.initials: C
authors.lastname: Mathiason
authors.forename: Edward
authors.initials: E
authors.lastname: Hoover
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003670:Deer; D034081:Wasting Disease, Chronic / Q000134:cerebrospinal fluid*