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的变化，导致影响疾病进展和结果的感染晚期病毒学事件。了解这些事件的影响是理解发病机制和急性感染后治疗方法的关键。病毒群体从早期使用CCR5 （R5）到后期使用CXCR4 （X4）作为进入辅受体的频繁切换可能是一个关键的晚期事件。无论是在没有治疗的情况下还是在HAART治疗下，X4病毒都与不良预后和更快的疾病进展有关。如果这种转换被阻止，进程就会减慢。进展的标志是初始CD4+ t细胞和胸腺新近产生的细胞的耗竭。这些细胞的丢失可能导致艾滋病发病前t细胞稳态的失败。幼稚t细胞优先表达CXCR4，因此X4病毒晚出现可能导致免疫缺陷。但目前尚不清楚X4病毒本身的特性，如复制适应性和细胞致病性，或X4宿主细胞范围本身，是否主要决定了X4在HIV发病机制中的作用。病毒适应性是病毒特性在不断变化的宿主环境中进化的复杂结果。健康、细胞病变和疾病是相关的，但不是完全相同的。为了阐明病毒进化与晚期感染发病机制之间的关系，我们建议：1)确定表征艾滋病进展的病毒遗传变化，以及HAART治疗下艾滋病进展和免疫重建的临床相关遗传预测因子；2)确定对辅助受体使用和病毒适应性重要的病毒遗传变化；3)阐明细胞群体生物学、病毒表型和适应度与疾病转归之间的关系。为了实现这些目标，我们将分析在多中心艾滋病队列研究（MACS）中从30名纵向采样的hiv感染男性中获得的T细胞群、原代病毒和病毒序列。其他患者的测序将不那么广泛，为基线基因型和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育方法进行分析，并对辅助受体的使用进行基因分型。病毒的适应性将通过体外竞争来评估，病毒的细胞致病性将通过体外凋亡/半胱天冬酶试验来测试。数据将与疾病进展标志物相关联，并通过对其他受试者的针对性分析，评估相关因素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.