title: Correlation between infectivity and disease associated prion protein in the nervous system and selected edible tissues of naturally affected scrapie sheep.
abstract: The transmissible spongiform encephalopathies (TSEs) or prion diseases are a group of fatal neurodegenerative disorders characterised by the accumulation of a pathological form of a host protein known as prion protein (PrP). The validation of abnormal PrP detection techniques is fundamental to allow the use of high-throughput laboratory based tests, avoiding the limitations of bioassays. We used scrapie, a prototype TSE, to examine the relationship between infectivity and laboratory based diagnostic tools. The data may help to optimise strategies to prevent exposure of humans to small ruminant TSE material via the food chain. Abnormal PrP distribution/accumulation was assessed by immunohistochemistry (IHC), Western blot (WB) and ELISA in samples from four animals. In addition, infectivity was detected using a sensitive bank vole bioassay with selected samples from two of the four sheep and protein misfolding cyclic amplification using bank vole brain as substrate (vPMCA) was also carried out in selected samples from one animal. Lymph nodes, oculomotor muscles, sciatic nerve and kidney were positive by IHC, WB and ELISA, although at levels 100-1000 fold lower than the brain, and contained detectable infectivity by bioassay. Tissues not infectious by bioassay were also negative by all laboratory tests including PMCA. Although discrepancies were observed in tissues with very low levels of abnormal PrP, there was an overall good correlation between IHC, WB, ELISA and bioassay results. Most importantly, there was a good correlation between the detection of abnormal PrP in tissues using laboratory tests and the levels of infectivity even when the titre was low. These findings provide useful information for risk modellers and represent a first step toward the validation of laboratory tests used to quantify prion infectivity, which would greatly aid TSE risk assessment policies.
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Francesca
authors: F
authors: Chianini
authors: Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
authors: Gian Mario
authors: GM
authors: Cosseddu
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Philip
authors: P
authors: Steele
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Scott
authors: S
authors: Hamilton
authors: Animal and Plant Health Agency (APHA -Weybridge), New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
authors: Jeremy
authors: J
authors: Hawthorn
authors: Animal and Plant Health Agency (APHA-Lasswade), Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Sílvia
authors: S
authors: Síso
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Yvonne
authors: Y
authors: Pang
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Jeanie
authors: J
authors: Finlayson
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Samantha L
authors: SL
authors: Eaton
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Hugh W
authors: HW
authors: Reid
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, United Kingdom.
authors: Mark P
authors: MP
authors: Dagleish
authors: Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
authors: Michele Angelo
authors: MA
authors: Di Bari
authors: Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
authors: Claudia
authors: C
authors: D'Agostino
authors: Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
authors: Umberto
authors: U
authors: Agrimi
authors: Animal and Plant Health Agency (APHA -Weybridge), New Haw, Addlestone, Surrey, KT15 3NB, United Kingdom.
authors: Linda
authors: L
authors: Terry
authors: Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
authors: Romolo
authors: R
authors: Nonno
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D007150:Immunohistochemistry; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D009420:Nervous System / Q000378:metabolism* / Q000473:pathology; D009801:Oculomotor Muscles / Q000378:metabolism / Q000473:pathology; D011328:Prions / Q000737:chemistry / Q000378:metabolism*; D012584:Sciatic Nerve / Q000378:metabolism / Q000473:pathology; D012608:Scrapie / Q000378:metabolism / Q000401:mortality / Q000473:pathology*; D012756:Sheep; D016019:Survival Analysis
chemical_list: D011328:Prions