HIV Neutralizing Antibodies: Isolation, characterization, and interaction with viral variants

抗HIV-1的中和抗体（NAb）可能是有效疫苗诱导的免疫应答的主要成分。交叉反应性NAb通常在HIV-1感染期间出现，尽管只有一小部分感染患者产生具有高宽度和效力的NAb。相比之下，迄今为止测试的HIV-1包膜糖蛋白（Env）疫苗免疫原未能引发交叉反应性中和抗体。因此，研究广泛中和抗体（bNAbs）在感染个体中的发展可能为疫苗设计提供重要的经验教训。此外，从选择的供体和接种疫苗的动物中分离bNAb极大地帮助我们理解HIV-1 Env结构和对中和抗体的脆弱性，并且这样的抗体具有预防或治疗HIV-1感染的潜力。 几年来，我们的实验室一直是从HIV感染者中分离和鉴定广泛中和抗体领域的领导者。我们率先开发了用于分离表位特异性B细胞的试剂，以及用于高通量筛选人B细胞的方法。通过这些方法之一鉴定后，我们通过单细胞PCR、亚克隆和在哺乳动物细胞中表达从B细胞回收IgG。测定所得抗体的病毒结合和中和，并分析其宽度、效力、表位和识别模式。我们还使用下一代深度测序来寻找抗体的克隆亲属，并了解它们在B细胞发育中的起源。对于后一项研究，我们从HIV感染时起就有纵向样本的捐赠者特别有价值。此外，我们将这些技术应用于研究用候选疫苗免疫的动物。 在过去的一年里，我们的工作包括：从多个成人和儿童HIV感染患者中分离出单克隆抗体，这些患者产生了广泛中和的血清，包括几年感染的纵向样本;从接种了候选HIV疫苗的恒河猴中分离出抗体并进行下一代测序分析，其中一些恒河猴随后感染了模型嵌合SIV-HIV病毒。

Neutralizing antibodies (NAb) against HIV-1 are likely to be a major component of an effective vaccine-induced immune response. Cross-reactive NAbs commonly arise during HIV-1 infection, though only a small subset of infected patients produce NAbs with high breadth and potency. In contrast, the HIV-1 envelope glycoprotein (Env) vaccine immunogens tested to date have failed to elicit cross-reactive neutralizing antibodies. Thus, studying the development of broadly neutralizing antibodies (bNAbs) in infected individuals may provide important lessons for vaccine design. In addition, the isolation of bNAbs from selected donors and vvaccinated animals has greatly aided our understanding of HIV-1 Env structure and vulnerability to neutralizing antibodies and such antibodies have potential for prevention or treatment of HIV-1 infection. For several years our lab has been a leader in the field of isolating and characterizing broadly neutralizing antibodies from HIV-infected donors. We have pioneered the development of reagents for isolating epitope-specific B cells, as well as a method for high-throughput screening of unselected B cells. After identification by one of these methods, we recover IgG from the B cells by single-cell PCR, subcloning, and expression in mammalian cells. The resulting antibodies are assayed for virus binding and neutralization, and their breadth, potency, epitopes, and modes of recognition analyzed. We also use next-generation deep sequencing to find clonal relatives of the antibodies and to understand their origins in B cell development. For the latter studies, donors for whom we have longitudinal samples from the time of HIV infection are particularly valuable. In addition, we apply these techniques to the study of animals that were immunized with candidate vaccines. In the past year, our work has included: isolation of monoclonal antibodies from multiple adult and pediatric HIV-infected patients that developed broadly neutralizing serum, including longitudinal samples over several years of infection; isolation and next-generation sequencing analysis of antibodies from rhesus macaques vaccinated with candidate HIV vaccines, some of which were subsequently infected with the model chimeric SIV-HIV virus.