Jacobs Jorg G, Langeveld Jan P M, Biacabe Anne-Gaëlle, Acutis Pier-Luigi, Polak Miroslaw P, Gavier-Widen Dolores, Buschmann Anne, Caramelli Maria, Casalone Cristina, Mazza Maria, Groschup Martin, Erkens Jo H F, Davidse Aart, van Zijderveld Fred G, Baron Thierry
Central Institute for Animal Disease Control (CIDC-Lelystad), 8203 AA 2004, Lelystad. The Netherlands.
J Clin Microbiol. 2007 Jun;45(6):1821-9. doi: 10.1128/JCM.00160-07. Epub 2007 Apr 18.
Transmissible spongiform encephalopathy strains can be differentiated by their behavior in bioassays and by molecular analyses of the disease-associated prion protein (PrP) in a posttranslationally transformed conformation (PrPSc). Until recently, isolates from cases of bovine spongiform encephalopathy (BSE) appeared to be very homogeneous. However, a limited number of atypical BSE isolates have recently been identified upon analyses of the disease-associated proteinase K (PK) resistance-associated moiety of PrPSc (PrPres), suggesting the existence of at least two additional BSE PrPres variants. These are defined here as the H type and the L type, according to the higher and lower positions of the nonglycosylated PrPres band in Western blots, respectively, compared to the position of the band in classical BSE (C-type) isolates. These molecular PrPres variants, which originated from six different European countries, were investigated together. In addition to the migration properties and glycosylation profiles (glycoprofiles), the H- and L-type isolates exhibited enhanced PK sensitivities at pH 8 compared to those of the C-type isolates. Moreover, H-type BSE isolates exhibited differences in the binding of antibodies specific for N- and more C-terminal PrP regions and principally contained two aglycosylated PrPres moieties which can both be glycosylated and which is thus indicative of the existence of two PrPres populations or intermediate cleavage sites. These properties appear to be consistent within each BSE type and independent of the geographical origin, suggesting the existence of different BSE strains in cattle. The choice of three antibodies and the application of two pHs during the digestion of brain homogenates provide practical and diverse tools for the discriminative detection of these three molecular BSE types and might assist with the recognition of other variants.
传染性海绵状脑病毒株可通过其在生物测定中的行为以及对疾病相关朊病毒蛋白（PrP）在翻译后转化构象（PrPSc）中的分子分析来区分。直到最近，牛海绵状脑病（BSE）病例的分离株似乎非常单一。然而，最近在对PrPSc（PrPres）的疾病相关蛋白酶K（PK）抗性相关部分进行分析时，鉴定出了少数非典型BSE分离株，这表明至少还存在另外两种BSE PrPres变体。根据与经典BSE（C型）分离株中条带位置相比，在蛋白质印迹中未糖基化PrPres条带的较高和较低位置，这里将它们分别定义为H型和L型。对来自六个不同欧洲国家的这些分子PrPres变体进行了共同研究。除了迁移特性和糖基化谱（糖谱）外，与C型分离株相比，H型和L型分离株在pH 8时对PK的敏感性增强。此外，H型BSE分离株在对N端和更C端PrP区域特异的抗体结合方面表现出差异，并且主要包含两个均可被糖基化的无糖基化PrPres部分，因此这表明存在两个PrPres群体或中间切割位点。这些特性在每种BSE类型中似乎是一致的，并且与地理来源无关，这表明牛中存在不同的BSE毒株。在脑匀浆消化过程中选择三种抗体并应用两种pH值，为区分检测这三种分子BSE类型提供了实用且多样的工具，并且可能有助于识别其他变体。
