Manipulating Epitope Immunodominance and Tracking B-cell-Antigen Interactions for Vaccine Design.

项目总结/摘要 传染病是严重和经常性的健康威胁。尤其令人担忧的是， 在短时间内变异并产生新的多样性。这些病毒适应新的宿主， 环境，并不断逃避宿主的抗病毒免疫反应。预防性疫苗是 非常可取;然而，没有明确的指导方针存在的有效疫苗的设计，迅速 变异病毒，如HIV-1、流感或目前的SARS-CoV 2，具有多种不同的流行变体。 尽管它们具有高度多样性，但病毒变体存在对于病毒适应性和适应性至关重要的保守区域。 传染性这些保守的表位是它们的致命弱点，也是基于抗体的疫苗设计的重点 努力针对高度变异病毒的疫苗应能引发特异性靶向 它可以识别病毒的保守区域，因为它可以识别并中和其变体的广泛多样性。 该领域的重大努力集中在工程化病毒免疫原以使其保守表位 更容易被抗体识别。不幸的是，靶向特异性保守的抗体应答， 感兴趣的表位是非常具有挑战性的。复杂抗原，例如病毒刺突蛋白，引发多克隆 由针对非保守表位的抗体主导的应答。这些抗体没有潜力广泛地 中和病毒，也干扰生发中心广泛保护性抗体的成熟。 为了诱导针对HIV-1保守表位的广泛中和抗体（bNAbs），我们最近 设计并评估了一种新的基于HIV-1包膜（Env）的引发免疫原， 野生型小鼠和猕猴中针对Env的保守表位的抗体;尽管取得了这一成就，这些 抗体显示对HIV-1没有中和活性，这表明额外的免疫接种将是必要的。 需要诱导bNAb。然而，在猕猴中进一步免疫引起多克隆抗体， 只有有限的效力和广度的反应，由Env的非保守表位的抗体主导。 基于这些观察，我假设减少对非保守病毒的干扰抗体应答， 表位，并跟踪有可能成为bNAb的抗体反应，将为bNAb铺平道路 开发和为疫苗设计工作提供信息。在这个建议中，我们将设计和评估一个新的 调节表位免疫优势的策略，这将使我们能够记录和跟踪 体内抗原-B细胞相互作用的历史。所提出的技术将用于定制 复合抗原的免疫显性特性，以指导抗体应答的表位 兴趣此外，我们将使用我们的新技术来条形码B细胞对多种免疫的反应， 追踪它们的命运并记录它们接触抗原的历史这项突破性的技术将提供非常 阐明B细胞对疫苗接种和感染应答的机制的有价值的信息， 并将大大有助于建立疫苗设计的指导方针。

PROJECT SUMMARY/ ABSTRACT Infectious diseases are serious and recurrent health threats. Particularly concerning are viruses with the capacity to mutate and generate de novo diversity in short periods of time. These viruses adapt to new hosts and environments, and continuously escape from the host anti-viral immune response. Preventative vaccines are highly desirable; however, no defined guidelines exist for the design of efficacious vaccines against rapidly mutating viruses such as HIV-1, influenza, or the current SARS-CoV2, with multiple different circulating variants. Despite their high diversity, viral variants present conserved regions that are essential for viral fitness and infectivity. These conserved epitopes are their Achilles heels, and the focus of antibody-based vaccine design efforts. A vaccine against a highly mutating virus should elicit an antibody response that specifically targets the conserved regions of the virus, as it would recognize and neutralize the broad diversity of its variants. Significant efforts in the field have focused on engineering viral immunogens to make their conserved epitopes more available for antibody recognition. Unfortunately, targeting antibody responses to specific conserved epitopes of interest is incredibly challenging. Complex antigens, such as viral spike proteins, elicit polyclonal responses dominated by antibodies to non-conserved epitopes. These antibodies have no potential to broadly neutralize the virus, and also interfere with the maturation of broadly protective antibodies in the germinal centers. Aiming to elicit broadly neutralizing antibodies (bNAbs) against a conserved epitope of HIV-1, we recently designed and evaluated a new HIV-1 Envelope (Env)-based priming immunogen, which elicited bNAb-like antibodies against a conserved epitope of Env in wild type mice and macaques; despite this achievement, these antibodies showed no neutralization activity against HIV-1, suggesting that additional immunization would be required to induce bNAbs. Nevertheless, further immunization in macaques elicited a polyclonal antibody response of only limited potency and breadth, dominated by antibodies to non-conserved epitopes of Env. Based on these observations, I hypothesize that reducing interfering antibody responses to non-conserved viral epitopes, and tracking the antibody responses with potential to become bNAbs, will pave the path towards bNAb development and inform vaccine design efforts. In this proposal, we will design and evaluate a novel strategy to modulate epitope immunodominance, which in addition, will allow us to record and track the history of antigen-B-cell interactions in vivo. The proposed technology will be used to customize the immunodominance properties of complex antigens in order to direct the antibody response to the epitopes of interest. In addition, we will use our new technology to barcode B cells responding to multiple immunizations, track their fates and record their history of antigen encounters. This groundbreaking technology will provide very valuable information to elucidate the mechanisms governing the B cell responses to vaccination and infection, and will significantly contribute to establish guidelines for vaccine design.