The influence of host barriers on viral quasispecies diversity and pathogenesis

宿主屏障对病毒准种多样性和发病机制的影响

基本信息

批准号：
7566022
负责人：
Julie K Pfeiffer
金额：
$ 31.4万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-02-15 至 2013-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7566022
关键词：
Accounting Animals Attenuated Attenuated Live Virus Vaccine Biological Assay Biological Models Blood - brain barrier anatomy Cells Complex Development Disease Drug resistance Equilibrium Evolution Gastrointestinal tract structure Genetic Genetic Recombination Genetic Variation Genome Human Human poliovirus Immune Injection of therapeutic agent Integration Host Factors Interferons Life Measures Mediating Mus Mutagenesis Mutation Natural Immunity Neuraxis Neurons Oral Paralysed Pathogenesis Patients Peripheral Poliomyelitis Poliovirus Vaccines Polioviruses Population RNA Viruses Research Role Route Safety Site TMEV Testing Time Transgenic Mice Vaccination Vaccine Design Vaccines Variant Viral Viral Vaccines Virulence Virulent Virus base cell type design experience fitness human poliovirus receptor laser capture microdissection microbial mutant novel pathogen poliovirus receptor public health relevance tool trafficking transmission process

项目摘要

DESCRIPTION (provided by applicant): Due to extensive genome variability, RNA virus populations exist as complex mutant populations called quasispecies. The diversity in the quasispecies complicates vaccine design, facilitates immune escape, and even confers drug resistance. For poliovirus, the ability to diversify its genome by mutagenesis is required for full virulence in infected animals. However, in infected mice, viral diversity is limited by bottlenecks that block quasispecies spread from the periphery to the CNS, thereby potentially limiting viral fitness. This bottleneck effect could explain why vaccine-associated poliomyelitis in humans is rare, despite the presence of virulent virus in the gut after vaccination with the attenuated Sabin poliovirus vaccine. The objective of this proposal is to use poliovirus as a model system to examine the mechanism of RNA virus bottlenecks, and to determine the effects of such bottlenecks on viral populations. The central hypothesis of this proposal is that physical barriers contribute to the bottleneck, and that the bottlenecked viral population has limited evolution capacity and reduced fitness. The contribution of physical barriers to the bottleneck following virus injection or oral inoculation will be determined in Aims 1 and 2 using a novel hybridization-based quasispecies diversity assay. Infected cells in the gut will be identified in Aim 3 using laser-capture microdissection and purification of live cells. In Aim 4, viral fitness and virulence thresholds will be measured in the presence or absence of the bottleneck. Elucidating this virulence threshold likely will be important for establishing the rational design of many live-attenuated viral vaccines. PUBLIC HEALTH RELEVANCE: RNA viruses such as poliovirus have incredible genome diversity, which complicates vaccine design, and can result in drug resistance. However, natural barriers called bottlenecks within an infected host can limit viral diversity, and possibly increase the safety of live-attenuated vaccines. The proposed research will determine which host factors contribute to the poliovirus bottleneck, and the effect of the bottleneck on the virulence of the virus.

描述（由申请人提供）：由于广泛的基因组变异性，RNA病毒群体作为称为准特性的复杂突变群存在。准特性的多样性使疫苗设计复杂化，促进免疫逃生，甚至赋予耐药性。对于脊髓灰质炎病毒，需要通过诱变来使受感染动物的全部毒力多样化。然而，在感染的小鼠中，病毒多样性受到瓶颈的限制，这些瓶颈阻断了从外围传播到中枢神经系统的准植物，从而可能限制了病毒适应性。这种瓶颈的作用可以解释为什么与疫苗相关的人类脊髓灰质炎在人类中很少见，尽管与减毒的Sabin脊髓灰质炎病毒疫苗接种后肠道中存在毒性病毒。该建议的目的是使用脊髓灰质炎病毒作为模型系统来检查RNA病毒瓶颈的机理，并确定此类瓶颈对病毒群体的影响。该提议的核心假设是物理障碍有助于瓶颈，并且瓶颈病毒种群的进化能力有限，并且适应性降低。病毒注射或口服接种后物理障碍对瓶颈的贡献将在AIMS 1和2中使用新型的基于杂交的准精子多样性分析确定。肠道中的感染细胞将在AIM 3中使用激光捕获显微解剖和活细胞的纯化。在AIM 4中，将在存在或不存在瓶颈的情况下测量病毒适应性和毒力阈值。阐明这种毒力阈值对于建立许多活体侵蚀病毒疫苗的合理设计可能很重要。公共卫生相关性：诸如脊髓灰质炎病毒之类的RNA病毒具有令人难以置信的基因组多样性，使疫苗设计复杂化，并可能导致耐药性。但是，受感染宿主中称为瓶颈的自然屏障可以限制病毒多样性，并可能提高活体内疫苗的安全性。拟议的研究将确定哪些宿主因素有助于脊髓灰质炎病毒瓶颈，以及瓶颈对病毒毒力的影响。