NR AXLV
AU Everest,D.J.; Waterhouse,S.; Kelly,T.; Velo-Rego,E.; Sauer,M.J.
TI Effectiveness of Capillary Electrophoresis Fluoroimmunoassay of Blood PrPsc for Evaluation of Scrapie Pathogenesis in Sheep
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Pathology and Pathogenesis P03.143
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Background: Development of a blood test for transmissible spongiform encephalopathies (TSEs) remains a high priority in order to minimize the possibility of iatrogenic transmission through blood transfusion, to further understanding of pathogenesis, and to facilitate pre-clinical diagnosis and management of disease in both humans and livestock. An immuno capillary electrophoresis (ICE) technique (capillary electrophoresis fluoroimmunoassay) has shown appreciable promise for detection of abnormal prion protein, and presents the possibility of diagnostic application and of advancing our limited understanding of the relationship between PrP genotype, infectivity, and the presence of PrPsc in blood.
Aim: To apply the ICE technique to investigate in detail the temporal occurrence of blood PrPsc with disease progression and thus to establish the potential of the test for pre-symptomatic scrapie diagnosis.
Methods: ICE 1,2 was used to analyse PrPsc in the white cell (buffy coat) fraction of blood, in a routine laboratory environment. The test sheep population was of various breeds (Swaledale, Welsh Mountain and Dorset) and PrP genotypes (ARQ/ARQ, ARQ/VRQ and VRQ/VRQ) which had been exposed to natural infection from birth. Control sheep were direct progeny of scrapie-free New Zealand stock.
Results: Analysis of extracted blood from test sheep (n=87, 347 samples) at various stages of incubation, and from control sheep (n=194, 489 samples), indicated that overall, test values for these populations were not significantly different, and that a similar proportion of control (7%) and test (10%) sheep were classified as positive. Over 2- 3 month intervals from birth until clinical disease, test specificity and sensitivity ranged from 66.7-100% and 0-66.7%, respectively, indicating poor diagnostic performance at all stages of pathogenesis.
Conclusion: In routine application, in its present form, the capillary electrophoresis fluoroimmunoassay procedure proved to be insufficiently robust for use as a blood test for scrapie diagnosis.3
References:
1. Schmerr MJ, Jenny AL, Bulgin MS, et al. (1999) J Chromatogr A 853:207-214. 2. Jackman R, Everest DJ, Schmerr MJ, et al. (2006) J AOAC Int 89:720-727. 3. Everest D, Waterhouse S, Kelly T, Velo-Rego, E and Sauer MJ. (2007) J Vet Diagn Invest 19: (5) (in press).
AD D.J. Everest, M.J. Sauer, Veterinary Laboratories Agency - Weybridge, Molecular Pathogenesis and Genetics, UK; S. Waterhouse, T. Kelly, E. Velo-Rego, Veterinary Laboratories Agency - Langford, UK
SP englisch
PO Schottland