HIV-1 Resistance to Chemokine Receptor Antagonists

描述（由申请人提供）：HIV-1进入靶细胞涉及病毒包膜蛋白与特定细胞表面受体的相互作用，最终导致病毒和宿主细胞膜的融合。这个多步骤的过程为药物开发提供了许多潜在的靶点。在目前的资助期内，在了解ENF耐药性的病毒动力学、适应性后果和临床意义方面取得了重大进展。我们现在建议将这些研究扩展到接受CCR5抑制剂治疗的患者的HIV-1分离株。由于趋化因子共受体在病毒侵入过程中的关键作用，它们是药物开发的重要靶点。几种小分子CCR5抑制剂在体外和hiv -1感染受试者中显示出有效的抗hiv -1活性，其中两种（马拉维洛克和维里维洛克）处于临床开发的后期阶段。对体外传代选择的马拉韦洛克和维里韦洛克耐药HIV-1分离株的研究表明，这些耐药病毒保留了它们的R5表型，并继续依赖CCR5进入[Pugach]。然而，对暴露于这些抑制剂的HIV-1分离株的特性知之甚少。此外，关于在药物压力下感染双性或混合R5和X4病毒的人的病毒准种变化的信息很少。因此，我们建议分析病毒在CCR5抑制剂vicriviroc存在下的复制适应性，使用从vicriviroc 2期研究中病毒学失败的受试者中获得的样本，艾滋病临床试验小组协议A5211。提出了以下四个具体目标：1)从维里维洛克治疗的CCR5抑制剂易感性降低的受试者中鉴定HIV-1包膜；2)在体内鉴定HIV-1 env基因型变化与病毒抗性相关；3)确定维氏抗性对病毒适合度的影响；4)检测抗维氏菌的HIV-1的进入动力学。对于后一个目标，我们将使用微制造皮升反应器大规模平行测序的新技术。这些实验的结果将与理解这类新型HIV-1治疗药物耐药性的机制和后果高度相关，并将为正确使用这些药物治疗HIV-1感染者提供必要的数据。

DESCRIPTION (provided by applicant): Entry of HIV-1 into target cells involves the interaction of viral envelope proteins with specific cell surface receptors, leading ultimately to fusion of viral and host cell membranes. This multi-step process offers a number of potential targets for drug development. During the current funding period, significant progress was made towards understanding the viral dynamics, fitness consequences and clinical significance of ENF resistance. We now propose to extend these studies to HIV-1 isolates from patients treated with CCR5 inhibitors. Because of their critical role in virus entry, the chemokine co-receptors are attractive targets for drug development. Several small-molecule CCR5 inhibitors have demonstrated potent anti-HIV-1 activity in vitro and in HIV-1-infected subjects, two of which (maraviroc and vicriviroc) are in advanced stages of clinical development. Studies of maraviroc- and vicriviroc-resistant HIV-1 isolates selected by in vitro passage show that these resistant viruses retain their R5 phenotype and continue to rely on CCR5 for entry [Pugach]. However, little is known about the properties of HIV-1 isolates selected by exposure to these inhibitors in vivo. In addition, scant information is available on shifts in the viral quasispecies in persons infected with dual-tropic or mixed R5 and X4 viruses under drug pressure. We therefore propose to analyze viral adaptation to replication in the presence of the CCR5 inhibitor vicriviroc using samples obtained from subjects with virologic failure in the phase 2 study of vicriviroc, AIDS Clinical Trials Group protocol A5211. The following four specific aims are proposed: 1) To identify HIV-1 envelopes from vicriviroc-treated subjects with reduced CCR5 inhibitor susceptibility; 2) to identify genotypic changes in HIV-1 env associated with vicriviroc resistance in vivo; 3) to determine the effect of vicriviroc resistance on viral fitness; 4) to examine the entry kinetics of vicriviroc-resistant HIV-1. For this latter aim we will use the novel technology of massively parallel sequencing using microfabricated picoliter reactors. Results of these experiments will be highly relevant to understanding the mechanisms and consequences of resistance to this novel class of HIV- 1 therapeutics and will provide data that are essential to their proper use in the treatment of HIV-1-infected individuals.