Open Access Research

The interpretation of disease phenotypes to identify TSE strains following murine bioassay: characterisation of classical scrapie

Katy E Beck1, Christopher M Vickery1, Richard Lockey2, Thomas Holder1, Leigh Thorne1, Linda A Terry3, Margaret Denyer1, Paul Webb1, Marion M Simmons1 and John Spiropoulos1*

Author Affiliations

1 Animal Health and Veterinary Laboratories Agency, Addlestone, Surrey KT15 3NB, United Kingdom

2 University of Southampton, University Road, Southampton, SO17 1BJ, United Kingdom

3 Université de Genève, 1 Rue Michel Servet, 1211, Geneva, 4, Switzerland

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Veterinary Research 2012, 43:77  doi:10.1186/1297-9716-43-77

Published: 1 November 2012

Abstract

Mouse bioassay can be readily employed for strain typing of naturally occurring transmissible spongiform encephalopathy cases. Classical scrapie strains have been characterised historically based on the established methodology of assessing incubation period of disease and the distribution of disease-specific vacuolation across the brain following strain stabilisation in a given mouse line. More recent research has shown that additional methods could be used to characterise strains and thereby expand the definition of strain “phenotype”. Here we present the phenotypic characteristics of classical scrapie strains isolated from 24 UK ovine field cases through the wild-type mouse bioassay. PrPSc immunohistochemistry (IHC), paraffin embedded tissue blots (PET-blot) and Western blotting approaches were used to determine the neuroanatomical distribution and molecular profile of PrPSc associated with each strain, in conjunction with traditional methodologies. Results revealed three strains isolated through each mouse line, including a previously unidentified strain. Moreover IHC and PET-blot methodologies were effective in characterising the strain-associated types and neuroanatomical locations of PrPSc. The use of Western blotting as a parameter to define classical scrapie strains was limited. These data provide a comprehensive description of classical scrapie strain phenotypes on isolation through the mouse bioassay that can provide a reference for further scrapie strain identification.