Replication cost to HIV-1 after escape from broadly neutralizing antibodies

逃离广泛中和抗体后 HIV-1 的复制成本

• 批准号: 9326905
• 负责人: Rebecca Marie Lynch
• 金额: $ 10.67万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-05 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9326905
• 关键词: Adult; Aftercare; Antibodies; Antibody Response; Autologous; Binding; Binding Sites; Biological Assay; CD4 Antigens; CD4 Positive T Lymphocytes; Cells; Chronic; Cloning; Data; Effectiveness; Employee; Epitopes; Exhibits; Genetic Drift; Glycoproteins; Goals; HIV Infections; HIV therapy; HIV-1; Human; Impairment; In Vitro; Individual; Infant; Infection; Infusion procedures; Longevity; Maps; Measures; Methods; Molecular Cloning; Monoclonal Antibodies; Monoclonal Antibody Therapy; Mutation; Neutralization Tests; Passive Immunization; Pathway interactions; Phenotype; Plasma; Prevention; Reproducibility; Research; Resistance; Satellite Viruses; Site; Site-Directed Mutagenesis; Surface; Testing; Vaccines; Vertebral column; Viral; Viral Load result; Viral Physiology; Viral reservoir; Virus; Virus Replication; antiretroviral therapy; cost; design; fitness; global health; improved; in vitro Assay; in vitro testing; in vivo; insight; interest; neutralizing antibody; neutralizing monoclonal antibodies; pressure; public health relevance; receptor; receptor binding; viral fitness; viral rebound

 DESCRIPTION (provided by applicant): HIV-1 is a major global health challenge, and although highly effective antiretroviral therapy (ARV) suppresses virus replication and extends lifespan, these ARV-treated individuals must maintain daily therapy to avoid viral rebound because a persistent viral reservoir is seeded early in infection. Recently, monoclonal antibodies (mAbs) that exhibit expanded breadth and potency against HIV-1 have been isolated, renewing interest in antibody treatment for chronic infection. Viral escape during mAb treatment; however, remains a concern. One class of broadly neutralizing antibodies (bNAbs) in particular, the VRC01-class, targets the highly conserved CD4 receptor-binding site (CD4bs) that is critical for viral function. Therefore, bNAbs could aid in treatment of chronic HIV infection by inducing unfavorable mutations that impair viral replication and lower viral burden in the instance of escape. To date, it remains unclear if viral escape from bNAbs impairs viral replication and if this effect would be reproducible across HIV-1 clades. As human trials with these bNAbs are currently in progress, these questions must be answered for the design of optimal mAb therapy. In this application we hypothesize that there is a replicative fitness cost to escape from the CD4bs directed VRC01-class of antibodies. We have preliminary data demonstrating that specific escape mutations from CD4bs bNAbs can impair viral replication in vitro. Here we propose to evaluate the potential replicative fitness cost after VRC01 escape in vivo by studying the escape pathway in the donor of VRC01. We will then assess selection pressure and viral escape in HIV-1 infected subjects passively infused with VRC01. Finally, we will develop in vitro replication assays to assess selection pressure of various bNAb combinations on genetically diverse viruses, including non-clade B viruses. HIV-1 is highly genetically diverse, presenting a problem for vaccine elicited antibodies, or passive infusion of antibodies for prevention or treatment. Therefore, there is great interest in using antibodies that target conserved sites of the virus, such as the CD4 receptor-binding site (CD4bs) found on the surface envelope glycoprotein (Env) of the virus. Recently, several CD4bs-directed broadly neutralizing antibodies have been isolated and characterized, but questions remain as to the mechanism of viral escape from these antibodies and whether there is a fitness cost associated with this neutralization escape. I hypothesize that because the epitope of these antibodies overlaps with the receptor-binding site, the virus will be less efficiet at binding to target cells (and therefore have lower replicative fitness) after escaping neutralization. My goal is to perform a detailed analysis of viral escape in a subject who developed a broadly neutralizing antibody response and from whom a potent monoclonal (VRC01) was isolated, and then compare this escape pathway to the potential escape pathway in chronically infected viremic adults who are treated with VRC01 as a therapy. I will employee well-described methods of molecular cloning, site-directed mutagenesis PCR, neutralization assays and in-vitro replication to achieve this goal. The overall aim of this proposal is to document how the virus escapes from monoclonal VRC01, what the functional consequences are in terms of viral fitness, and therefore to provide key insights as to how to improve the effectiveness of passive immunization therapy for use in HIV-1 infected individuals.

 描述（由申请人提供）：HIV-1是一个主要的全球健康挑战，尽管高效的抗逆转录病毒治疗（ARV）抑制病毒复制并延长寿命，但这些接受ARV治疗的个体必须维持每日治疗以避免病毒反弹，因为持久的病毒储存库在感染早期就被播种。最近，已经分离出针对HIV-1表现出扩展的宽度和效力的单克隆抗体（mAb），重新引起了对慢性感染的抗体治疗的兴趣。mAb治疗期间的病毒逃逸;然而，仍然是一个问题。一类广泛中和抗体（bNAb），特别是VRC 01类，靶向对病毒功能至关重要的高度保守的CD 4受体结合位点（CD 4 bs）。因此，bNAb可以通过诱导不利的突变来帮助治疗慢性HIV感染，这些突变会损害病毒复制并在逃逸的情况下降低病毒负荷。迄今为止，尚不清楚病毒从bNAb逃逸是否会损害病毒复制，以及这种效应是否会在HIV-1进化枝中重现。由于这些bNAb的人体试验目前正在进行中，这些问题必须得到回答，以设计最佳的mAb治疗。 在本申请中，我们假设存在从CD 4 bs指导的VRC 01类抗体逃逸的复制适应性成本。我们有初步的数据表明，特异性逃逸突变的CD 4 bs bNAb可以损害病毒复制在体外。在这里，我们建议通过研究VRC 01供体的逃逸途径来评估VRC 01逃逸后体内潜在的复制适应性成本。然后，我们将评估被动输注VRC 01的HIV-1感染受试者的选择压力和病毒逃逸。最后，我们将开发体外复制试验，以评估各种bNA B组合对遗传多样性病毒（包括非进化枝B病毒）的选择压力。 HIV-1具有高度的遗传多样性，这给疫苗引发的抗体或被动输注用于预防或治疗的抗体带来了问题。因此，人们对使用靶向病毒保守位点的抗体非常感兴趣，例如在病毒表面包膜糖蛋白（Env）上发现的CD 4受体结合位点（CD 4 bs）。最近，已经分离出几种CD 4 b定向的广泛中和抗体并进行了表征，但关于病毒从这些抗体逃逸的机制以及是否存在与这种中和逃逸相关的适应性成本的问题仍然存在。我假设，由于这些抗体的表位与受体结合位点重叠，病毒在逃避中和后与靶细胞结合的效率较低（因此具有较低的复制适应性）。我的目标是对一名产生广泛中和抗体应答并从中分离出强效单克隆（VRC 01）的受试者进行病毒逃逸的详细分析，然后将该逃逸途径与接受VRC 01治疗的慢性感染病毒血症成人的潜在逃逸途径进行比较。我将采用分子克隆、定点突变PCR、中和试验和体外复制等精心描述的方法来实现这一目标。本提案的总体目标是记录病毒如何从单克隆VRC 01中逃逸，就病毒适应性而言功能性后果是什么，因此提供关于如何提高被动免疫治疗用于HIV-1感染者的有效性的关键见解。