NR AOWL
AU Mazza,M.; Martucci,F.; Crescio,M.I.; Casalone,C.; Maniaci,M.G.; Nodari,S.; Caramelli,M.; Acutis,P.L.
TI PrPsc Detection in Neural and Extraneural Tissues of Sheep from a Scrapie Outbreak by Western Blot Using Sodium Phosphotungstic Acid (NaPTA) Precipitation
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - DG-42
PT Konferenz-Poster
AB PrPsc detection in peripheral tissues has been considered in many studies for a preclinical diagnosis of scrapie. However, some authors found that PrPsc doesn't always accumulate earlier in lymphoid tissue than in central nervous system (CNS), probably owing to genotype influence. Some scrapie cases with positivity only at CNS were also reported. PrPsc detection is technically more difficult in extraneural tissues and diagnostic tests may loose sensitivity. Therefore we used a highly sensitive immunoblot, based on NaPTA precipitation, to study an Italian scrapie outbreak and verify the possible role of peripheral tissues in scrapie diagnosis. Fifty over 1 year old Biellese sheep were analysed. Brainstem, lymph nodes, spleen, ileum from all the animals and placenta from ewes in advanced pregnancy were examined. Brainstem and lymph nodes were also analysed by immunohistochemistry. Genotype of the PrP gene was determined in all the sheep and foetuses. Only two positive animals were found: one showed the presence of PrPsc in all tissues except in placenta, while the second was positive in brainstem but negative in peripheral tissues. Genetic analysis revealed the following results: ARQ/ARQ(62%), ARQ/ARR(22%), ARQ/AHQ(6%), ARR/ARR(4%), ARQ/VRQ(4%), AHQ/ARH(2%). Positive animals were ARQ/ARQ. The absence of PrPsc in the placenta of scrapie-positive ewe, despite a susceptible fetal genotype (ARQ/ARQ), could be referred to absence of PrPsc in this tissue or to an erroneous sampling. The negativity of the lymphoid tissue in the second scrapie-positive animal may be attributed, as reported by other authors, to genetic factors or to a higher dose peripheral infection. Our results showed that NaPTA precipitation can be a useful and easy method to detect PrPsc in the more difficult to treat peripheral tissues but that these tissues are not always the right target for a preclinical diagnosis.This research was founded by the Ministry of Health (1AA/F3).
AD M. Mazza, F. Martucci, M.I. Crescio, C. Casalone, M.G. Maniaci, S. Nodari, M. Caramelli, P.L. Acutis, CEA- Istituto Zooprofilattico Sperimenta del Piemonte, Liguria e Valle d'Aosta
SP englisch
PO Deutschland