NR ATQI
AU Chianini,F.; Finlayson,J.; Hamilton,S.; Eaton,S.L.; Steele,P.; Jeffrey,M.J.; Reid,H.W.; Rodger,S.M.; Gonzalez,L.
TI PrPsc distribution in the placentas of Suffolk ewes from a flock naturally infected with scrapie
QU International Conference - Prion 2005: Between fundamentals and society's needs - 19.10.-21.10.2005, Congress Center Düsseldorf - Poster Session: Pathogenesis PATH-45
PT Konferenz-Poster
AB
Infectivity of the placenta was demonstrated at the beginning of the 1970's but the interpretation of results lacked precision as disease diagnosis relied on clinical signs and histopathology and PrPsc and the influence of genotype susceptibility were unknown. In light of the improved understanding of the disease, our aim is to re-examine placentas to provide more precise information.
Samples of placentas from ARQ/ARQ, ARR/ARQ and ARR/ARR Suffolk ewes from a naturally infected flock were collected at lambing in 2002, 2004 and 2005. The lambs were genotyped and serial tonsil biopsies as well as samples at post-mortem (brain and lymphoid tissues) were taken from the ewes to assess PrPsc status by immunohistochemistry (IHC). The samples of placenta were examined with immunohistochemical and immunochemical methods to assess the distribution of PrPsc. For IHC a panel of antibodies recognising different epitopes of PrP were used (R145, L42, P4 and 6H4). Western blot analysis was performed using NaPTA precipitation and SDS-PAGE (Novex system) and PrPsc visualised by chemiluminescence after probing with P4 and 6H4 monoclonal antibodies. Studies with an ELISA to detect PrPsc, adapted to peripheral tissue, are ongoing and will add further information. So far, results have shown that positive placentas are from ARQ/ARQ ewes carrying ARQ/ARQ lambs as previously reported by other authors, however in one such case results were negative. This ewe was found to be negative by tonsil biopsy on 4 occasions, 3 before and 1 after placenta was collected. However, following the development of clinical signs of scrapie, the ewe was culled and positive labelling was confirmed in the brain and lymphoid tissues collected at post mortem. These findings show that in a number of sheep PrPsc detection in peripheral tissues is only possible in an advanced phase of the disease, however further studies are needed to investigate whether placentas are infectious when PrPsc cannot be detected.
IN Nicht bei ARR/ARR-Schafen, aber bei ARQ/ARQ-Schafen mit ARQ/ARQ-Lämmern in einer Scrapie-Herde fanden die Autoren PrPsc in den Plazenten Scrapie-infizierter Tiere.
AD F.Chianini, J.Finlayson, S.Hamilton, S.L.Eaton, P.Steele, H.W.Reid, S.M.Rodger, Moredun Research Institute, Scotland, UK; M.Jeffrey, L.Gonzalez, Veterinary Laboratories Agency, Scotland, UK
SP englisch
PO Deutschland