Quasispecies Evolution During Lentivirus Persistence

描述(申请人提供)：这些研究的长期目标是描绘慢病毒病和持久性的病毒决定因素。遗传多样性是慢病毒感染的一个标志。体内的病毒群体是由相关的遗传型和表型变种的异质混合组成的，每个变种都有可能在面对环境变化时成为主导。这项研究的目的是确定在免疫成熟和临床潜伏期是否优先选择复制适合性改变的病毒变体。由于已知慢病毒的环境随疾病进展而变化，这项研究可能提供第一个确凿的证据，证明其他基因的选择与宿主免疫环境的变化有关。这项初步研究将利用特征明确的马传染性贫血病毒(EIAV)模型来检验这一假设，即免疫成熟和临床静止的开始与REV活性降低的病毒变异的选择有关。在第一个具体目标中，来自感染EIAV的马的回溯性样本将用于临床疾病期间REV准种的纵向和横断面分析。遗传和计算工具将在临床疾病和免疫成熟的不同阶段建立准种进化的一般模式。在第二个特定目的中，在特定目的1中确定的REV基因类型将在瞬时表达分析中进行功能鉴定。准种REV表型将使用单个变种活性的加权平均值来确定，统计分析将确定准种REV表型的变化是否与临床疾病的特定阶段相关。将构建REV嵌合前病毒以确定REV变异对病毒复制的影响。第三个具体目标将开发一个表型变异和免疫成熟的数学模型，以探索在具有成熟免疫反应的宿主中可能选择不太适合的变种的假设。这些研究的完成将证明次级基因座在疾病进展中的重要性，揭示多基因座模型的生物学相关性和实用性，并为包括疾病进展的额外病毒和宿主参数在内的更现实和更复杂的模型奠定基础。

DESCRIPTION (provided by applicant): The long range goal of these studies is to delineate viral determinants of lentivirus disease and persistence. Genetic diversity is a hallmark of lentivirus infections. In vivo populations of virus are comprised of a heterogeneous mix of related genotypic and phenotypic variants, each with the potential to become dominant in the face of environmental change. The goal of this study is to determine if virus variants with altered replication fitness are preferentially selected during periods of immune maturation and clinical latency. As lentiviruses are already known to vary in env with disease progression, this study may provide the first definitive evidence that other genes are selected in association with changes in the host immune environment. This pilot study will utilize the well-characterized equine infectious anemia virus (EIAV) model to test the hypothesis that immune maturation and the onset of clinical quiescence are associated with selection of viral variants with decreased Rev activity. In the first specific aim, retrospective samples from EIAV-infected horses will be used in longitudinal and cross-sectional analyses of Rev quasispecies during clinical disease. Genetic and computational tools will establish the general patterns of quasispecies evolution at different stages of clinical disease and immune maturation. In the second specific aim, Rev genotypes identified in Specific Aim 1 will be functionally characterized in transient expression assays. The quasispecies Rev phenotype will be determined using a weighted average of the activity of individual variants, and statistical analyses will determine if changes in quasispecies Rev phenotype correlate with specific stages of clinical disease. Rev chimeric proviruses will be constructed to determine the effect of Rev variation on virus replication. The third specific aim will develop a mathematical model of phenotype variation and immune maturation to explore in silico the hypothesis that less fit variants may be selected in a host with a mature immune response. Completion of these studies will demonstrate the importance of secondary loci in disease progression, reveal the biological relevance and utility of multi-locus modets, and form a basis for more realistic and complex models that include additional virus and host parameters of disease progression.