Molecular determinants of cellular resistance to Newcastle disease virus infection

纽卡斯尔病（ND）是世界上最严重的禽类疾病之一，ND的爆发代表了对加拿大家禽业的永远存在的威胁：这是一项数十亿美元的业务，大大增加了加拿大经济。ND是由副粘病毒科Avulavirus属的纽卡斯尔病病毒（NDV）引起的。在世界范围内，通过大规模的疫苗接种计划来控制ND。尽管如此，50多年的广泛疫苗接种未能阻止病毒在全球范围内的传播和演变。事实上，尽管在最佳施用时能够预防临床体征，但疫苗不赋予无菌免疫力，并且不能防止攻击病毒的复制和脱落。由于缺乏无菌免疫和NDV突变率高，ND已被证明在许多国家几乎不可能根除。如果利用对NDV具有降低的感染率的动物，则有可能显著降低病毒传播、进化的速率并降低控制ND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纽卡斯尔病病毒感染的抗性的决定因素，这可能最终导致通过新的克隆或选择性育种策略产生抗新城疫病毒的鸟类。鉴定NDV核糖核蛋白复合物中通过重叠感染排斥（SE）现象诱导抗NDV感染的组分.鉴定能抑制NDV复制的抗NDV RNP胞内抗体.利用基因组步移策略在单倍体细胞系中发现NDV感染和复制所必需的细胞基因。拟议的目标重点是在细胞水平上发现和表征对NDV感染产生抗性的决定因素。重复感染排除现象的表征和NDV特异性胞内抗体的发现致力于表征用于生产不仅对NDV而且对家禽的其他传染因子具有抗性的转基因鸟类的平台的首要目标。发现和鉴定负责细胞对NDV的抗性的宿主基因最终可以导致更合理的亲本家禽种群的选择性育种策略。拟议的研究，同时调查对NDV感染的抗性的基本机制，有可能提高我们在全球范围内控制ND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.