title: Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie.
abstract: Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641-a rare scrapie variant-could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrP(res)) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrP(res) found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrP(res) population. The existence of these 2 PrP(res) populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing.
authors.affiliation: a Department of Infection Biology ; Central Veterinary Institute part of Wageningen UR ; Lelystad , The Netherlands.
authors.forename: Jan P M
authors.initials: JP
authors.lastname: Langeveld
authors.forename: Jorg G
authors.initials: JG
authors.lastname: Jacobs
authors.forename: Jo H F
authors.initials: JH
authors.lastname: Erkens
authors.forename: Thierry
authors.initials: T
authors.lastname: Baron
authors.forename: Olivier
authors.initials: O
authors.lastname: Andréoletti
authors.forename: Takahashi
authors.initials: T
authors.lastname: Yokoyama
authors.forename: Lucien J M
authors.initials: LJ
authors.lastname: van Keulen
authors.forename: Fred G
authors.initials: FG
authors.lastname: van Zijderveld
authors.forename: Aart
authors.initials: A
authors.lastname: Davidse
authors.forename: Jim
authors.initials: J
authors.lastname: Hope
authors.forename: Yue
authors.initials: Y
authors.lastname: Tang
authors.forename: Alex
authors.initials: A
authors.lastname: Bossers
mesh_terms: D000818:Animals; D002417:Cattle; D016643:Encephalopathy, Bovine Spongiform / Q000378:metabolism / Q000473:pathology*; D006031:Glycosylation; D010447:Peptide Hydrolases / Q000378:metabolism; D018620:PrPSc Proteins / Q000032:analysis* / Q000378:metabolism; D012608:Scrapie / Q000378:metabolism / Q000473:pathology*; D012756:Sheep / Q000502:physiology*
chemical_list: D018620:PrPSc Proteins; D010447:Peptide Hydrolases
keywords: AVG, average; BSE, bovine spongiform encephalopathy; CH1641; IHC, immunohistochemistry; PK, proteinase K; PrPC ,prion protein in cellular form; PrPSc, prion protein in TSE associated form; PrPres, proteinase K resistant fragment of PrPSc; SD, standard deviation; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis; TE, tissue equivalents; TSE, transmissible spongiform encephalopathy; VC, variation coefficient.; Western blot; ic., intracerebrally; ip., intraperitoneally; prion; sheep; triplex-WB, triplex Western blotting method; typing