Targeting the HIV reservoir using optimized anti-HIV antibodies

使用优化的抗 HIV 抗体靶向 HIV 储存库

• 批准号: 10179304
• 负责人: Pamela J Bjorkman
• 金额: $ 41.08万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10179304
• 关键词: ADCC Assay; AIDS/HIV problem; Anti-Retroviral Agents; Architecture; Avidity; Binding; Biological Assay; Cross-Linking Reagents; Crystallization; DNA; Drug resistance; Engineering; Epitopes; Evolution; Exhibits; Generations; Goals; HIV; HIV Antibodies; HIV-1; Half-Life; Homo; Immunity; Immunoglobulin G; In Vitro; Individual; Infection; Libraries; Linker DNA; Measures; Mediating; Molecular; Mutation; Patients; Persons; Pharmaceutical Preparations; Play; Population; Predisposition; Production; Public Health; Reagent; Research; Resistance; Role; Serum; Structural Protein; Structure; Therapeutic; Therapeutic Uses; Time; Vaccines; Viral; Viral Load result; Viral reservoir; Virion; Virus; Virus Latency; antigen binding; antiretroviral therapy; base; cost; crosslink; density; design; experimental study; immunogenicity; improved; natural antibodies; neonatal Fc receptor; neutralizing antibody; novel; prevent; receptor; side effect; small molecule; synergism; viral rebound; viral resistance

Summary The rapid mutation rate of HIV-1 results in many thousands of viral strains, thus thwarting current vaccine efforts. Although HIV-1 infection can be controlled by anti-retroviral therapy (ART), the virus rebounds within weeks of ART cessation because complete elimination of HIV-1 is prevented by latent viral reservoirs. Broadly neutralizing antibodies (bNAbs) against the HIV-1 envelope spike (Env) that have been isolated from a subset of HIV-1–infected donors are protective against HIV-1 infection and can lower the viral load after infection, and it has been suggested that bNAbs could play a role in eliminating the viral reservoir. However, HIV-1 can evade even the most potent bNAbs by mutation. Here we seek to engineer bNAbs to be resistant to viral mutation so they could be used to eliminate viral reservoirs. Our strategy relies upon harnessing avidity effects to prevent viral resistance to bNAbs at both an individual and population level. We hypothesize that HIV-1 hinders IgGs from using both antigen-binding Fabs to bind bivalently. This is accomplished by the small number and low density of HIV-1 Env spikes, which prevent most IgGs from inter-spike crosslinking (bivalent binding between spikes), and the architecture of the Env trimer, which impedes intra-spike crosslinking (bivalent binding within a spike). We suggested that predominantly monovalent binding expands the range of HIV-1 mutations permitting Ab evasion, whereas reagents capable of bivalent binding through intra-spike crosslinking would be more potent across multiple strains of HIV-1. This hypothesis was supported by our demonstration of up to 100-fold increases in geometric mean potency achieved with our first generation intra- spike crosslinking reagents (homo- and hetero-diFabs joined by rigid DNA linkers). These results support the hypothesis that HIV's low spike density contributes to vulnerability of HIV-1 bNAbs to spike mutations and suggests that the ideal anti-HIV therapeutic for eliminating HIV reservoirs would utilize avidity to achieve intra- spike crosslinking because this sort of therapeutic would reduce the concentration required for sterilizing immunity and be resistant to Env mutations. Here we propose to design, produce, and evaluate second generation intra-spike crosslinking reagents with two improvements: (i) they will contain an IgG Fc to mediate effector functions and increase the serum half-life, and (ii) the DNA will be replaced by structured protein linkers. We will also evaluate the effects of Fc substitutions designed to enhance Fc-mediated effector functions through tighter binding to activating FcγR receptors and improve serum half-life through enhanced binding to FcRn, including a novel computational design strategy to improve binding to FcRn under conditions that promote increased IgG half-life. These more potent bNAbs could be used therapeutically at lower concentrations and thus reduce cost and/or production time, increase the number of patients being treated, and lower the potential for immunogenicity or other side-effects related to bNAb administration.

概括 HIV-1的快速突变导致数千种病毒株，从而挫败了电流疫苗 尽管HIV-1感染可以通过抗逆转录病毒疗法（ART）控制，但病毒反弹 数周的戒烟是因为由潜在病毒储层阻止了完全消除HIV-1。广泛 与已从子集分离的HIV-1信封尖峰（ENV）中和抗体（BNABS） HIV-1感染者的供体受到保护，免受HIV-1感染，并可以降低感染后的病毒载量，并且 有人提出，BNAB可以在消除病毒库中发挥作用。但是，HIV-1可以 通过突变逃避最潜在的bnabs。在这里，我们试图设计bnabs以抵抗病毒 突变，因此可以用来消除病毒库。我们的策略依赖于利用亲发效应 为了防止在个体和人口水平上对BNAB的病毒抗性。我们假设HIV-1 阻碍IgG使用两种抗原结合晶圆厂以偶性结合。这是由小的 HIV-1 env峰值的数量和低密度，这阻止了大多数IgG的尖峰交联（二价 尖峰之间的绑定）和env架子的结构，这会阻碍尖峰交联 （在尖峰中二价结合）。我们建议主要单价结合扩大了 HIV-1突变允许AB逃避，而试剂能够通过尖峰内的二价结合 在多种HIV-1菌株中，交联将更有潜力。这个假设得到了我们的支持 我们的第一代内部的几何平均效力最多增加了100倍 尖峰交联试剂（由刚性DNA接头连接的同型和异型键）。这些结果支持 假设HIV的低峰值密度有助于HIV-1 BNABS对峰值突变和 提出理想的抗HIV疗法来消除HIV储藏剂将利用亲戚来实现内部 尖峰交联，因为这种疗法会降低消毒所需的浓度 免疫力并抗性突变。在这里，我们建议设计，生产和评估第二 具有两个改进的生成尖峰交联试剂：（i）它们将包含IgG FC进行介导 效应子功能并增加血清半衰期，（ii）DNA将被结构化蛋白取代 链接器。我们还将评估旨在增强FC介导的效应器的FC取代的影响 通过与激活FcγR受体的紧密结合并通过增强来改善血清半衰期的功能 与FCRN结合，包括一种新型的计算设计策略，以改善条件下与FCRN的结合 这促进了IgG半衰期的增加。这些潜在的BNAB可以在较低的地方热使用 浓度，从而减少成本和/或生产时间，增加接受治疗的患者数量， 并降低与BNAB给药有关的免疫原性或其他副作用的潜力。