Cervid to human prion transmission

 描述(由申请人提供)：Pron病是可传播的，并且总是致命的。慢性消耗性疾病(CWD)是一种影响鹿、麋鹿和驼鹿的普恩病毒疾病，到目前为止，它是一种广泛且不断扩大的流行病，影响到美国22个州和加拿大2个省。CWD在北美构成了最严重的人畜共患病病毒传播风险，这是因为大量的鹿肉消费(仅在美国每年就有600万头鹿/麋鹿被猎杀和消费)，受CWD影响的宫颈的肌肉和其他组织/体液中有显著的Prion感染性，以及通常只有家人和朋友食用受影响的动物而导致个人接触CWD的高水平。然而，我们仍然不知道CWD普恩病毒是否可以感染人类的大脑或周围组织，或者是否已经发生了临床/无症状的CWD人畜共患病，我们也没有文章可靠地检测CWD在人类中的感染。我们假设：(1)经典的CWD病毒株可在脑和外周淋巴组织中低水平感染人类；(2)宫颈至人类的传播屏障依赖于CWD病毒株，并受宿主(人类)Prion蛋白(PrP)初级序列的影响；(3)可以建立可靠的论文来检测CWD在人类中的感染；以及(4)CWD已经向人类传播。我们将使用转基因(TG)小鼠模型和互补的体外方法在4个目标上验证这些假设。目的1通过使用不同剂量和途径的CWD分离株在一组表达常见人类PrP变异体的人源化TG小鼠品系中进行系统生物检测，证明经典的CWD毒株可以在低水平感染人类大脑或外周淋巴组织。目标2将通过检测和比较几个非典型/不寻常的CWD分离株/菌株以及来自其他物种的几个适应CWD PrP序列的PrP菌株的传播效率和表型，利用与目标1相同的人源化TG小鼠株系，验证宫颈到人类的PrP传播屏障依赖于PrP序列并受宿主(人)PrP序列影响的假设。从AIMS 1-2产生的现有和未来的实验性“人CWD”样本的生化和体外种子特性，并将它们与常见的散发性人类克雅氏病(SCJD)普恩病毒进行比较。AIM 4将利用AIM 3中建立的标准和论文，通过检测大量来自CWD流行区食用鹿肉的美国和加拿大受Pron影响的人类受试者的大脑样本，尝试检测临床CWD人类病例。这项建议的发现将极大地促进我们对CWD在人类中传播的潜在和特征的理解，建立可靠的CWD人畜共患病论文，并可能在人类中发现首例CWD感染病例(S)。

 DESCRIPTION (provided by applicant): Prion disease is transmissible and invariably fatal. Chronic wasting disease (CWD) is the prion disease affecting deer, elk and moose, and it is a widespread and expanding epidemic affecting 22 US States and 2 Canadian provinces so far. CWD poses the most serious zoonotic prion transmission risks in North America because of huge venison consumption (>6 million deer/elk hunted and consumed annually in the USA alone), significant prion infectivity in muscles and other tissues/fluids from CWD-affected cervids, and usually high levels of individual exposure to CWD resulting from consumption of the affected animal among often just family and friends. However, we still do not know whether CWD prions can infect humans in the brain or peripheral tissues or whether clinical/asymptomatic CWD zoonosis has already occurred, and we have no essays to reliably detect CWD infection in humans. We hypothesize that: (1) The classic CWD prion strain can infect humans at low levels in the brain and peripheral lymphoid tissues; (2) The cervid-to-human transmission barrier is dependent on the cervid prion strain and influenced by the host (human) prion protein (PrP) primary sequence; (3) Reliable essays can be established to detect CWD infection in humans; and (4) CWD transmission to humans has already occurred. We will test these hypotheses in 4 Aims using transgenic (Tg) mouse models and complementary in vitro approaches. Aim 1 will prove that the classical CWD strain may infect humans in brain or peripheral lymphoid tissues at low levels by conducting systemic bioassays in a set of "humanized" Tg mouse lines expressing common human PrP variants using a number of CWD isolates at varying doses and routes. Experimental "human CWD" samples will also be generated for Aim 3. Aim 2 will test the hypothesis that the cervid-to-human prion transmission barrier is dependent on prion strain and influenced by the host (human) PrP sequence by examining and comparing the transmission efficiency and phenotypes of several atypical/unusual CWD isolates/strains as well as a few prion strains from other species that have adapted to cervid PrP sequence, utilizing the same panel of humanized Tg mouse lines as in Aim 1. Aim 3 will establish reliable essays for detection and surveillance of CWD infection in humans by examining in details the clinical, pathological, biochemical and in vitro seeding properties of existing and future experimental "human CWD" samples generated from Aims 1-2 and compare them with those of common sporadic human Creutzfeldt-Jakob disease (sCJD) prions. Aim 4 will attempt to detect clinical CWD-affected human cases by examining a significant number of brain samples from prion-affected human subjects in the USA and Canada who have consumed venison from CWD-endemic areas utilizing the criteria and essays established in Aim 3. The findings from this proposal will greatly advance our understandings on the potential and characteristics of cervid prion transmission in humans, establish reliable essays for CWD zoonosis and potentially discover the first case(s) of CWD infection in humans.