Optimization of novel immunogen design to elicit broadly protective immune responses against influenza viruses

项目摘要 我们对针对保守性抗体的广泛中和抗体（bnAbs）的性质的理解 流感病毒表位在过去五年中迅速演变，但我们仍在解开关键特征 以及这类抗体的功能。整个计划项目资助的首要目标是 通过接种疫苗产生针对流感病毒的长期、广泛的保护性免疫应答。为此目的， 我们的研究小组已经开发出新的免疫原和疫苗接种方案， 基于嵌合血凝素（cHA）的动物模型和候选疫苗目前正朝着 I期临床试验。 项目1中提出的工作旨在促进下一代免疫原的开发， 2流感A病毒（IAV）和流感B病毒（IBV），努力克服免疫优势， HA的球状头部结构域，并允许提高对高度保守但免疫亚显性的 HA表位。应用我们先前在甲型流感cHA免疫原方面的专业知识， 推进新的第2组cHA结构。然而，开发真正通用的流感病毒疫苗 将需要联合努力以引起针对组1和2 IAV以及IBV的bnAb应答。因此，我们认为， 我们建议基于新的“镶嵌”HA设计， 免疫显性HA头部结构域中的哪些主要抗原位点已被消除。优化的cHA， 第2组IAV，或IBV的嵌合免疫原，将作为DNA、重组蛋白、灭活 流感疫苗（IIV）或减毒活流感疫苗（LAIV）制剂在小鼠中引起 广泛的和保护性的体液免疫应答识别保守的表位。与此同时，我们将继续 为了进一步阐明Fc介导的保护作用的决定因素，使用新的技术来探测相互作用， 广泛保护性HA抗体、受感染的靶细胞和效应细胞之间。这些机制将 扩展到研究识别其他流感病毒抗原的抗体的作用，包括 病毒神经氨酸酶（NA），与项目4合作。本工作计划将通过关闭 与其他项目的合作。我们将描述人和鼠的单克隆抗体 (mAb)由Project 4和mAb Core生产。疫苗构建体将与选定的佐剂一起配制 在项目2中，看看我们是否可以增强针对保守表位的抗体应答， 在项目3中，将在雪貂模型中评价先导疫苗免疫原的效力。因此， 我们的项目是确定广泛保护性免疫反应的独特特性， 进一步加强和帮助开发通用流感病毒疫苗。

PROJECT SUMMARY Our understanding of the properties of broadly-neutralizing antibodies (bnAbs) directed towards conserved influenza virus epitopes has rapidly evolved in the last five years and yet, we are still unraveling key features and functions of this antibody class. The overarching goal of this entire Program Project Grant is the generation of long-lived, broadly protective immune responses to influenza virus by vaccination. To this end, our group has developed novel immunogens and vaccination regimens that have yielded promising results in animal models and candidate vaccines based on chimeric hemagglutinins (cHA) are now advancing towards Phase I clinical trials. The work proposed in Project 1, seeks to advance the development of next-generation immunogens for group 2 influenza A viruses (IAVs) and influenza B viruses (IBVs), in an effort to overcome the immunodominance of the globular head domain of HA, and allow improved recognition of highly conserved, but immunosubdominant HA epitopes. The application of our prior expertise with influenza A cHA immunogens will allow us to rapidly advance new group 2 cHA constructs. However, the development of a truly universal influenza virus vaccine will require combined efforts to elicit bnAb responses against group 1 and 2 IAVs as well as IBVs. Therefore, we propose to generate new universal influenza B virus constructs, based on novel "mosaic" HA design in which major antigenic sites in the immunodominant HA head domain have been eliminated. Optimized cHA for group 2 IAVs, or mosaic immunogens for IBVs, will be tested as DNA, recombinant protein, inactivated influenza vaccine (IIV) or live attenuated influenza vaccine (LAIV) formulations in mice for their ability to elicit broad and protective humoral immune responses recognizing conserved epitopes. In parallel, we will continue to further elucidate the determinants of Fc-mediated protection using novel techniques to probe the interactions between broadly protective HA antibodies, infected target cells, and effector cells. These mechanisms will be extended to investigations of the role of antibodies recognizing additional influenza viral antigens, including the viral neuraminidase (NA), in collaboration with Project 4. This program of work will be executed through close collaborations with each of the other Projects. We will characterize human and murine monoclonal antibodies (mAb) produced by Project 4 and the mAb Core. Vaccine constructs will be formulated with adjuvants selected in Project 2 to see if we can enhance Ab responses directed towards conserved epitopes and the in vivo efficacy of lead vaccine immunogens will be evaluated in the ferret model in Project 3. Thus, the overall aim of our project is to identify unique properties of broadly protective immune responses that can be exploited to further enhance and aid in the development of universal influenza virus vaccines.