Broadly neutralizing antibody combinations with single virions in HIV+ plasma

最近广泛发现的艾滋病毒中和抗体(BNAbs)正在积极研究艾滋病毒/艾滋病 治疗、功能治愈和/或预防。各种这样的bNAb是已知的，并根据它们的 HIV包膜上的表位簇(Env)。严格的临床前研究表明， 比目前使用的抗逆转录病毒药物(ARV)更具工程价值的bNAbs；包括不经常使用，风险较低 副作用和遗传毒性、针对潜在艾滋病毒宿主的能力、促进宿主抗病毒免疫 对常规抗逆转录病毒耐药性不敏感。当前，实现这一目标的主要障碍是 单个bNAbs的临床潜力在于，它们在覆盖表位变异方面都表现出局限性，这使得病毒 逃走。一种合乎逻辑的缓解策略是利用三个bNAb的组合，每个bNAb针对不同的表位 集群。促进bNAbs与相同靶点(病毒粒子或三聚体)的广泛并发结合的组合 在血浆中，病毒群体预计会特别具有抗逃逸能力。然而，这个目标是否以及如何能够 为预防或治疗艾滋病毒而获得的药物仍不清楚。传统的中和分析不能直接 测量bNab-病毒粒子结合，但已经表明组合bNab类可以提高广度和效力。 模型预测，bNab类组合可以共同作用于单一病毒株。然而，临床试验 建议用一幅更复杂的图景。几项试验已经测试了联合的bNAbs，但持续抑制 病毒血症尚未得到证实。总的来说，这些发现提出了几个重要的问题 关于体内并发的bNab结合：某些bNab类组合在 在血浆病毒群的主要部分中建立并发病毒粒子/三聚体结合？如何始终如一 这种令人满意的覆盖范围是否发生在个人和亚型之间？HIV+人类血浆中是否含有 免疫活性颗粒(外体、未成熟的病毒粒子)；循环中的抗环境病毒抗体或其他 扰乱理想的并发绑定模式？该项目的目标是通过直接分析来回答这些问题 天然血浆中bNab-病毒粒子相互作用的研究。我们的假设是，这一独特的努力是可以实现的 通过新的定量单分子和荧光相关光谱(FCS)检测方法 应用于血浆病毒粒子的原位检测。目的1.建立bNab的免疫反应模式 针对单个病毒粒子或包膜三聚体的组合；目的2.表征bNAbs和bNab的相互作用 与HIV+血浆中单个病毒粒子的组合。项目输出将是史无前例的数据层 体内bNab联合作用的性质以及三种bNab组合对抗艾滋病毒逃逸的前景。 我们的数据将独一无二地定义使用bNab组合来瞄准循环的原则、限制和机会 HIV+人群中的病毒粒子。这些知识应该会影响bNab类组合的选择 用于未来的临床试验，并告知过去和正在进行的临床试验的结果。此外，质的和 来自该项目的定量数据将为开发针对患者的bNab级鸡尾酒的可行性提供依据。

Recently discovered broadly HIV-neutralizing antibodies (bnAbs) are being actively investigated for HIV/AIDS treatment, functional cure and/or prevention. A variety of such bnAbs are known and classified according to their epitopes clusters on the HIV envelope (Env). Rigorous preclinical studies evince potential advantages of engineered bnAbs over currently used antiretroviral drugs (ARVs); including infrequent administration, lower risk of side effects and genotoxicity, capacity to target latent HIV reservoirs, promotion of host antiviral immune responses, and insensitivity to conventional ARV resistance. Currently, the major obstacle for realizing the clinical potential of single bnAbs is that all of them exhibit limits in covering epitope variability, which allows virus escape. One logical mitigation strategy is to utilize combinations of three bnAbs, each targeting a distinct epitope cluster. Combinations that promote extensive concurrent binding of bnAbs to the same targets (virions or trimers) in plasma virus populations are expected to be especially escape resistant. Yet whether and how this goal can be obtained for HIV prevention or therapy remains unclear. Conventional neutralization assays do not directly measure bnAb-virion binding but have shown that combining bnAb classes improves breadth and potency. Models predict that bnAb class combinations can act collectively on a single virus strain. However, clinical trials suggest a more complex picture. Several trials have tested combined bnAbs, but sustained suppression of viremia has not yet been demonstrated. Collectively, these findings introduce several important questions regarding concurrent bnAb binding in vivo: Are certain bnAb class combinations distinguishable as “superior” in establishing concurrent virion/trimer binding within major fractions of plasma virus swarms? How consistently does such desirable coverage occur across individuals and subtypes? Does HIV+ human plasma contain immunoreactive particles (exosomes, immature virions); circulating anti-Env antibodies or other factors that perturb desirable concurrent binding patterns? Goal of the project is to answer these questions by direct analyses of bnAb-virion interactions in native plasma. Our hypothesis is that this unique endeavor can be accomplished by novel quantitative single molecule and fluorescence correlation spectroscopy (FCS) detection methods applied to plasma virions in situ. Two Specific Aims are: Aim 1. Establish the immunoreactivity patterns of bnAb combinations against single virions or envelope trimers; Aim 2. Characterize interactions of bnAbs and bnAb combinations with single virions in HIV+ plasma. Project output will be an unprecedented tier of data informing the nature of combined bnAb action in vivo and prospects for triple bnAb combinations to counter HIV escape. Our data will uniquely define principles, limits, and opportunities in using bnAb combinations to target circulating virions in the HIV+ human population. This knowledge should impact the selection of bnAb class combinations for future clinical testing and inform the outcomes of past and ongoing clinical trials. Further, the qualitative and quantitative data from this project will inform the feasibility of developing patient-specific bnAb class cocktails.