HIV-1 and Host Cell Changes in Disease Progression

描述(由申请人提供)：病毒进化过程和宿主细胞群体的变化导致影响疾病进展和结果的晚期感染病毒学事件。了解这些事件的影响是理解发病机制以及急性感染后治疗最能使患者受益的方法的关键。病毒群体从早期使用CCR5(R5)到后来使用CXCR4(X4)作为进入辅助受体的频繁转换可能是一个关键的晚期事件。无论是在缺乏治疗的情况下还是在HAART下，X4病毒都与预后较差和疾病进展较快有关。如果这一转变被阻止，进展可能会放缓。进展的标志是原始的CD4+T细胞和最近由胸腺产生的细胞耗尽。这些细胞的丧失可能是艾滋病发病前T细胞内稳态失调的原因之一。幼稚T细胞优先表达CXCR4，因此X4病毒出现较晚可能导致免疫缺陷。但目前还不清楚是X4病毒本身的特性，如复制适合性和细胞致病性，还是X4宿主细胞本身的范围，主要定义了X4在HIV致病中的作用。病毒适合性是在不断变化的宿主环境中进化的病毒特性的复杂结果。健康、细胞病变和疾病是相关的，但不是相同的。为了阐明病毒进化和晚期感染发病机制之间的关系，我们建议：1)确定以艾滋病进展为特征的病毒基因变化，以及HAART下进展和免疫重建的临床相关基因预测因子；2)确定对辅助受体使用和病毒适合性重要的病毒基因变化；以及3)澄清细胞群体生物学、病毒表型和适应性以及疾病结局之间的关系。为了实现这些目标，我们将分析多中心艾滋病队列研究(MACS)中从30名纵向采样的HIV感染者中获得的T细胞群、主要病毒和病毒序列。更多的患者将不那么广泛地进行测序，为基线基因和疾病进展之间的相关性研究提供数据。病毒包膜基因将使用系统发生学方法进行分析，并为辅助受体的使用进行基因分型。病毒的适合性将通过体外竞争来评估，病毒的细胞致病性将使用体外细胞凋亡/半胱氨酸天冬氨酸氨基转移酶试验来测试。数据将与疾病进展的标志相关联，并将通过对其他受试者的有针对性的分析，评估相关者预测导致疾病的关键事件的能力。

DESCRIPTION (provided by applicant): Processes of viral evolution, and changes in host cell populations, lead to late-infection virological events that impact disease progression and outcome. Understanding the effects of such events is key to comprehending pathogenesis and the ways that post-acute-infection therapy can best benefit patients. The frequent switch of the viral population from the early use of CCR5 (R5) to the later use of CXCR4 (X4) as entry coreceptor may be a critical late event. X4 virus is associated with poor prognosis and faster disease progression, both in the absence of therapy and under HAART. Were this switch prevented, progression could be slowed. Progression is marked by depletion of naive CD4+ T-cells and cells recently produced by the thymus. Loss of these cells may contribute to the failure of T-cell homeostasis that precedes AIDS onset. Naive T-cells preferentially express CXCR4, so that late appearance of X4 virus may lead to immune deficiency. But it is not clear if properties of X4 viruses themselves, such as replicative fitness and cytopathicity, or X4 host cell range per se, mainly define the X4 role in HIV pathogenesis. Viral fitness is the complex result of evolving virus properties in the changing host environment. Fitness, cytopathicity, and disease are related, but not identical. In an effort to clarify the relationship between viral evolution and late-infection pathogenesis, we propose to 1) identify viral genetic changes that characterize progression to AIDS, and clinically relevant genetic predictors of progression and immune reconstitution under HAART; 2) identify viral genetic changes important to coreceptor usage and viral fitness; and, 3) clarify the relationships among cell population biology, viral phenotype and fitness, and disease outcome. To achieve these aims, we will analyze T cell populations, primary viruses and viral sequences obtained from 30 longitudinally-sampled HIV-infected men in the Multicenter AIDS Cohort Study (MACS). Additional patients will be sequenced less extensively, providing data for a study of correlation between baseline genotype and progression. Viral envelope genes will be analyzed using phylogenetic methods, and genotyped for coreceptor usage. Fitness of viruses will be assessed by in vitro competition, and cytopathicity of viruses will be tested using an in vitro apoptosis/caspase assay. Data will be correlated with markers of disease progression, and correlates will be assessed for their ability to predict the critical events leading to disease, by targeted analysis of additional subjects.