Langeveld Jan P M, Jacobs Jorg G, Erkens Jo H F, Baron Thierry, Andréoletti Olivier, Yokoyama Takahashi, van Keulen Lucien J M, van Zijderveld Fred G, Davidse Aart, Hope Jim, Tang Yue, Bossers Alex
a Department of Infection Biology ; Central Veterinary Institute part of Wageningen UR ; Lelystad , The Netherlands.
Prion. 2014;8(4):296-305. doi: 10.4161/19336896.2014.983396.
Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641-a rare scrapie variant-could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrP(res)) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrP(res) found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrP(res) population. The existence of these 2 PrP(res) populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing.
区分朊病毒感染绵羊的牛海绵状脑病（BSE）和羊瘙痒病的努力已经产生了判定不存在BSE的有效方法。在极少数情况下，由于假设BSE、经典羊瘙痒病和CH1641（一种罕见的羊瘙痒病变体）可能以混合形式出现，仍存在不确定性。在包括死亡家畜样本在内的现场样本中，对朊病毒蛋白（PrP(res)）疾病相关形式的蛋白酶K抗性部分的分子特性变化进行三联免疫印迹分析，是一种用于快速鉴别目的的强大工具。在本研究中，我们检查了7例偏离典型特征的羊瘙痒病现场病例，以了解在CH1641型羊瘙痒病、经典羊瘙痒病和BSE中发现的PrP(res)的一些典型分子特征。其中1例在非糖基化部分的分子量和N端12B2表位含量方面与羊瘙痒病最为接近。2例与经典羊瘙痒病不同，但特征不够明显，无法区分是BSE还是CH1641。其他4例表现出介于羊瘙痒病和CH1641之间的特征，分子量和12B2表位含量降低，同时存在第二个PrP(res)群体。通过PNGaseF去糖基化进一步证实了这两个PrP(res)群体的存在。研究结果表明，使用当前的生化方法，经典羊瘙痒病、CH1641和BSE之间的鉴别诊断可能无法得出明确结论。这些中间病例是否代表传染性海绵状脑病（TSE）毒株的混合物，应进一步研究，例如在对易感性不同的啮齿动物品系进行生物测定或采用其他适合毒株分型的技术。
