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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 12
pubmed:dateCreated
2008-11-14
pubmed:abstractText
Despite intensive studies on sheep scrapie, a number of questions remain unanswered, such as the natural mode of transmission and the amount of infectivity which accumulates in edible tissues at different stages of scrapie infection. Studies using the mouse model proved to be useful for recognizing scrapie strain diversity, but the low sensitivity of mice to some natural scrapie isolates hampered further investigations. To investigate the sensitivity of bank voles (Myodes glareolus) to scrapie, we performed end-point titrations from two unrelated scrapie sources. Similar titres [10(5.5) ID50 U g(-1) and 10(5.8) ID50 U g(-1), both intracerebrally (i.c.)] were obtained, showing that voles can detect infectivity up to 3-4 orders of magnitude lower when compared with laboratory mice. We further investigated the relationships between PrPSc molecular characteristics, strain and prion titre in the brain and tonsil of the same scrapie-affected sheep. We found that protease-resistant PrPSc fragments (PrPres) from brain and tonsil had different molecular features, but induced identical disease phenotypes in voles. The infectivity titre of the tonsil estimated by incubation time assay was 10(4.8) i.c. ID50 U g(-1), i.e. fivefold less than the brain. This compared well with the relative PrPres content, which was 8.8-fold less in tonsil than in brain. Our results suggest that brain and tonsil harboured the same prion strain showing different glycoprofiles in relation to the different cellular/tissue types in which it replicated, and that a PrPSc-based estimate of scrapie infectivity in sheep tissues could be achieved by combining sensitive PrPres detection methods and bioassay in voles.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-1317
pubmed:author
pubmed:issnType
Print
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2975-85
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
The bank vole (Myodes glareolus) as a sensitive bioassay for sheep scrapie.
pubmed:affiliation
Department of Veterinary Public Health and Food Safety, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Evaluation Studies