Alicon AG, Schlieren, Switzerland.
PLoS One. 2006 Dec 20;1(1):e71. doi: 10.1371/journal.pone.0000071.
Prions are known to cause transmissible spongiform encephalopathies (TSE) after accumulation in the central nervous system. There is increasing evidence that prions are also present in body fluids and that prion infection by blood transmission is possible. The low concentration of the proteinaceous agent in body fluids and its long incubation time complicate epidemiologic analysis and estimation of spreading and thus the risk of human infection. This situation is particularly unsatisfactory for food and pharmaceutical industries, given the lack of sensitive tools for monitoring the infectious agent.
METHODOLOGY/PRINCIPAL FINDINGS: We have developed an adsorption matrix, Alicon PrioTrap, which binds with high affinity and specificity to prion proteins. Thus we were able to identify prion protein (PrP(C))--the precursor of prions (PrP(Sc))--in milk from humans, cows, sheep, and goats. The absolute amount of PrP(C) differs between the species (from microg/l range in sheep to ng/l range in human milk). PrP(C) is also found in homogenised and pasteurised off-the-shelf milk, and even ultrahigh temperature treatment only partially diminishes endogenous PrP(C) concentration.
CONCLUSIONS/SIGNIFICANCE: In view of a recent study showing evidence of prion replication occurring in the mammary gland of scrapie infected sheep suffering from mastitis, the appearance of PrP(C) in milk implies the possibility that milk of TSE-infected animals serves as source for PrP(Sc).
已知朊病毒在中枢神经系统中积累后会引起传染性海绵状脑病(TSE)。越来越多的证据表明,朊病毒也存在于体液中,并且通过血液传播可能会感染朊病毒。体液中蛋白质剂的浓度低,潜伏期长,这使得流行病学分析和传播风险的评估变得复杂。对于食品和制药行业来说,这种情况尤其令人不满意,因为缺乏监测感染剂的敏感工具。
方法/主要发现:我们开发了一种吸附基质 Alicon PrioTrap,它与朊病毒蛋白具有高亲和力和特异性。因此,我们能够在来自人类、牛、羊和山羊的牛奶中识别出朊病毒蛋白(PrP(C))——朊病毒(PrP(Sc))的前体。物种之间 PrP(C)的绝对数量不同(从绵羊的μg/l 范围到人类牛奶的 ng/l 范围)。PrP(C)也存在于均质化和巴氏杀菌的现成牛奶中,甚至超高温处理也只能部分降低内源性 PrP(C)浓度。
结论/意义:鉴于最近的一项研究表明,在患有乳腺炎的感染朊病毒的绵羊的乳腺中存在朊病毒复制的证据,牛奶中出现 PrP(C)意味着 TSE 感染动物的牛奶可能成为 PrP(Sc)的来源。