title: Susceptibility to scrapie and disease phenotype in sheep: cross-PRNP genotype experimental transmissions with natural sources.
abstract: It has long been established that the sheep Prnp genotype influences the susceptibility to scrapie, and some studies suggest that it can also determine several aspects of the disease phenotype. Other studies, however, indicate that the source of infection may also play a role in such phenotype. To address this question an experiment was set up in which either of two different natural scrapie sources, AAS from AA136 Suffolk and VVC from VV136 Cheviot sheep, were inoculated into AA136, VA136 and VV136 sheep recipients (n = 52). The immunohistochemical (IHC) profile of disease-associated PrP (PrPd) accumulation in the brain of recipient sheep was highly consistent upon codon 136 homologous and semi-homologous transmission, but could be either similar to or different from those of the inoculum donors. In contrast, the IHC profiles were highly variable upon heterologous transmission (VVC to AA136 and AAS to VV136). Furthermore, sheep of the same Prnp genotype could exhibit different survival times and PrPd profiles depending on the source of infection, and a correlation was observed between IHC and Western blot profiles. It was found that additional polymorphisms at codons 112 or 141 of AA136 recipients resulted in a delayed appearance of clinical disease or even in protection from infection. The results of this study strongly suggest that the scrapie phenotype in sheep results from a complex interaction between source, donor and recipient factors, and that the Prnp genotype of the recipient sheep does not explain the variability observed upon codon 136 heterologous transmissions, arguing for other genetic factors to be involved.
authors: Animal Health and Veterinary Laboratories Agency, Pentlands Science Park, Bush Loan, Midlothian, EH26 0PZ, United Kingdom. lorenzo.gonzalez@ahvla.gsi.gov.uk.
authors: Lorenzo
authors: L
authors: González
authors: Martin
authors: M
authors: Jeffrey
authors: Mark P
authors: MP
authors: Dagleish
authors: Wilfred
authors: W
authors: Goldmann
authors: Sílvia
authors: S
authors: Sisó
authors: Samantha L
authors: SL
authors: Eaton
authors: Stuart
authors: S
authors: Martin
authors: Jeanie
authors: J
authors: Finlayson
authors: Paula
authors: P
authors: Stewart
authors: Philip
authors: P
authors: Steele
authors: Yvonne
authors: Y
authors: Pang
authors: Scott
authors: S
authors: Hamilton
authors: Hugh W
authors: HW
authors: Reid
authors: Francesca
authors: F
authors: Chianini
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D004198:Disease Susceptibility / Q000662:veterinary; D005260:Female; D008297:Male; D010641:Phenotype; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011110:Polymorphism, Genetic; D011328:Prions / Q000235:genetics* / Q000378:metabolism; D012608:Scrapie / Q000235:genetics* / Q000378:metabolism / Q000635:transmission*; D012756:Sheep
chemical_list: D011328:Prions