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From: TSS ()
Dynamics and genetics of PrPSc placental accumulation in sheep 1 UMR INRA ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, 31076 Toulouse, France Placentae from scrapie-affected ewes are an important source of contamination. This study confirmed that scrapie-incubating ewes bearing susceptible genotypes could produce both abnormal prion protein (PrPSc)-positive and -negative placentae, depending only on the PRP genotype of the fetus. The results also provided evidence indicating that scrapie-incubating ARR/VRQ ewes may be unable to accumulate prions in the placenta, whatever the genotype of their progeny. Multinucleated trophoblast cells appeared to play a key role in placental PrPSc accumulation. PrPSc accumulation began in syncytiotrophoblasts before disseminating to uninucleated trophoblasts. As these result from trophoblast/uterine epithelial cell fusion, syncytiotrophoblast cells expressed maternal and fetal PrPC, whilst uninucleated trophoblast cells only expressed fetal PrPC. In ARR/VRQ scrapie-infected ewes, expression of the ARR allele by syncytiotrophoblasts appeared to prevent initiation of PrPSc placental deposition. The absence of prions in affected ARR/VRQ sheep placentae reinforces strongly the interest in ARR selection for scrapie control. http://vir.sgmjournals.org/cgi/content/abstract/88/3/1056?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=prion&searchid=1&FIRSTINDEX=0&volume=88&issue=3&resourcetype=HWCIT TSS
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