The placenta is important in the horizontal transmission of the aetiological agent in scrapie-affected sheep. It has been demonstrated that the placentas of fetuses carrying the dimorphism Q171R of the gene is resistant to pathological prion protein (PrP) accumulation in the placenta. To test whether other polymorphisms are associated with a lack of placental PrP deposition, we carried out a study on 26 naturally and 11 experimentally scrapie-affected ewes with or without clinical signs. PrP was detected in the placenta of ARQ/ARQ fetuses by Western blot and immunohistochemical analysis, but not in ARQN/ARQK or, as expected, ARQ/ARR samples. Furthermore, three of four ALRQ/AFRQ placentas were also PrP negative, suggesting that the dimorphism at codon 141 may also mediate placental deposition of PrP. This finding demonstrates for the first time that fetal polymorphisms, other than those at codon 171, are associated with the lack of placental deposition of PrP.


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vol. , part 9, pp. 2402 - 2407

Quantification of PrP in ARQ/ARQ and AL RQ/AF RQ placental homogenates from the twin pregnancy [PDF](253 KB)


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