title: Emergence of multiple prion strains from single isolates of ovine scrapie.
abstract: The infectious agent associated with prion diseases such as ovine scrapie shows strain diversity. Ovine prion strains have typically been identified by their transmission properties in wild-type mice. However, strain typing of ovine scrapie isolates in wild-type mice may not reveal properties of the infectious prion agent as they exist in the original host. This could be circumvented if ovine scrapie isolates are passaged in ovine prion protein (PrP)-transgenic mice. This study used incubation time, lesion profile, immunohistochemistry of the disease-associated PrP (PrP(Sc)) and molecular profile to compare the range of ovine prion strains that emerged from sheep scrapie isolates following serial passage in wild-type and ovine PrP transgenic mice. It was found that a diverse range of ovine prion strains emerged from homozygous ARQ and VRQ scrapie isolates passaged in wild-type and ovine PrP transgenic mice. However, strain-specific PrP(Sc) deposition and PrP27-30 molecular profile patterns were identified in ovine PrP transgenic mice that were not detected in wild-type mice. Significantly, it was established that the individual mouse brain selected for transmission during prion strain typing had a significant influence on strain definition. Serial passage of short- and long-incubation-time animals from the same group of scrapie-inoculated mice revealed different prion strain phenotypes. These observations are consistent with the possibility that some scrapie isolates contain more than one prion strain.
authors.affiliation: University of Cambridge, Department of Veterinary Medicine, Madingley Road, Cambridge CB3 0ES, UK.
authors.forename: Alana M
authors.initials: AM
authors.lastname: Thackray
authors.affiliation: University of Cambridge, Department of Veterinary Medicine, Madingley Road, Cambridge CB3 0ES, UK.
authors.forename: Lee
authors.initials: L
authors.lastname: Hopkins
authors.affiliation: Veterinary Laboratories Agency, Department of Pathology and Host Susceptibility, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Lockey
authors.affiliation: Veterinary Laboratories Agency, Department of Pathology and Host Susceptibility, Weybridge, New Haw, Addlestone, Surrey KT15 3NB, UK.
authors.forename: John
authors.initials: J
authors.lastname: Spiropoulos
authors.affiliation: University of Cambridge, Department of Veterinary Medicine, Madingley Road, Cambridge CB3 0ES, UK.
authors.forename: Raymond
authors.initials: R
authors.lastname: Bujdoso
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011328:Prions / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012608:Scrapie / Q000378:metabolism* / Q000473:pathology; D012692:Serial Passage; D012756:Sheep
chemical_list: D011328:Prions