Molecular determinants of cellular resistance to Newcastle disease virus infection

新城疫病（ND）是世界上最严重的禽类疾病之一，ND的爆发对加拿大家禽业构成了永远存在的威胁：这是一个数十亿美元的行业，大大增加了加拿大的经济。新城疫是由新城疫病毒（NDV）毒株引起的，NDV是副粘病毒科阿武拉病毒属的一员。ND的控制是通过大规模疫苗接种规划在世界范围内进行的。尽管如此，50多年来的广泛疫苗接种未能阻止病毒在世界范围内的传播和演变。事实上，疫苗虽然能够在适当的情况下预防临床症状，但不能提供无菌免疫，也不能防止挑战病毒的复制和脱落。由于缺乏无菌免疫和NDV高突变率，ND在许多国家已被证明几乎不可能根除。如果使用对新城疫感染率较低的动物，就有可能大大降低病毒传播和进化的速度，并降低控制新城疫的成本。这项新研究计划的长期目标是在细胞水平上发现和表征对新城疫病病毒感染的抗性决定因素，这可能最终导致通过新的克隆或选择性育种策略产生耐新城疫病病毒的鸟类。根据这个总体目标，我的短期目标是：1。鉴定通过重复感染排斥（SE）现象诱导对NDV感染产生抗性的NDV核糖核蛋白（RNP）复合物组分。鉴定抗新城疫病病毒RNP的体内抗体，抑制新城疫病病毒复制。在单倍体细胞系中使用基因组行走策略发现对新城疫病病毒感染和复制至关重要的细胞基因。提出的目标侧重于在细胞水平上发现和表征对NDV感染的抗性决定因素。对重复感染排斥现象的表征，以及NDV特异性体内体的发现，都是一个重要的目标，即表征一个生产转基因鸟类的平台，该平台不仅对NDV具有抗性，而且对家禽的其他传染性病原体也具有抗性。对NDV细胞抗性的宿主基因的发现和鉴定，最终可以为亲本家禽种群提供更合理的选择育种策略。本研究旨在探讨新城疫感染的基本耐药机制，有可能提高我们在全球范围内控制新城疫的能力。

Newcastle disease (ND) is one of the most severe avian diseases worldwide, and ND outbreaks represent an ever-present threat to the Canadian poultry industry: a multibillion dollar business that significantly adds to the Canadian economy. ND is caused by strains of Newcastle disease virus (NDV), a member of the Avulavirus genus, Paramyxoviridae family. Control of ND is carried out worldwide through large-scale vaccination programs. Nonetheless, over 50 years of extensive vaccination has failed to prevent the spread and evolution of the virus worldwide. In fact, although able to prevent clinical signs when optimally administered, vaccines do not confer sterile immunity, and cannot prevent replication and shedding of the challenge virus. Because of lack of sterile immunity and the high NDV mutation rates, ND has proven all but impossible to eradicate in many countries. If animals that have a reduced rate of infection against NDV are utilized, it may be possible to considerably decrease the rate of viral spread, evolution and to decrease the cost of controlling ND.The long-term goal of this new research program is to discover and characterize determinants of resistance to Newcastle disease virus infection at a cellular level, which could ultimately lead to generation of NDVresistant birds through novel cloning or selective breeding strategies.Pursuant to this overarching goal, my short-term objectives are:1. To identify components of the NDV ribonucleoprotein (RNP) complex that can induce resistance to NDV infection through the superinfection exclusion (SE) phenomenon.2. To identify intrabodies against NDV RNP that can inhibit NDV replication.3. To discover cellular genes that are essential for NDV infection and replication, using a genome walking strategy in a haploid cell line.Significance. The proposed Objectives focus on discovery and characterization of determinants of resistance to NDV infection at a cellular level. Characterization of the superinfection exclusion phenomenon, and discovery of NDV-specific intrabodies commits to an over-riding goal to characterize a platform for production of transgenic birds that are resistant not only to NDV, but also to other infectious agents of poultry. Discovery and characterization of host genes responsible for cellular resistance to NDV can eventually lead to more rational selective breeding strategies of parent poultry stocks. The proposed research, while investigating basic mechanisms of resistance to NDV infection, has the potential to improve our ability to control ND on a global scale.