Development of a broadly neutralizing influenza virus vaccine

描述(申请人提供)：流感病毒每年都会导致严重的发病率和死亡率。预防流感病毒感染的疫苗是可用的，但它们必须每年重新配制，因为它们的效力仅限于季节性毒株。流感病毒的高突变率，特别是病毒表面蛋白血凝素(HA)高度可变的抗原结构是这一问题的核心。流感病毒疫苗依赖于对HA的抗体反应，疫苗的生产是基于对哪些毒株在特定季节最有可能传播的预测。这些预测可能不准确，导致疫苗无效。此外，它们没有考虑到2009年H1N1“猪流感”爆发所体现的大流行毒株的出现。每年的疫苗接种活动也很昂贵，而且在相当一部分人口中，对疫苗接种的抵抗力越来越强。一种针对季节性和大流行毒株提供终身保护的通用流感病毒疫苗将是解决这些问题的办法。我们提出了一种新的策略来开发这种通用的流感病毒疫苗。该策略是基于最近在流感HA中发现的一个广泛中和表位。我们计划将这个表位嫁接到基于昆虫病毒鸡舍病毒(FHV)的病毒样颗粒(VLP)平台的表面。FHV VLP允许以多价方式呈现外源表位，并诱导强大的抗体反应。显示HA表位的嵌合FHV颗粒将通过冷冻EM和图像重建以及使用广泛中和的单抗进行结合分析来表征其结构。然后这些颗粒将被用来接种小鼠，它们的抗体反应将通过ELISA法和微量中和试验来表征。预计免疫的小鼠会产生中和抗体，这一点将通过对活病毒的挑战研究来证实。如果成功，拟议的研究可能会通过消除目前与这一努力相关的挑战来导致流感疫苗接种的转变。 公共卫生相关性：在这项申请中，我们建议开发一种新的流感病毒疫苗，只需接种一次，然后终身预防所有季节性和大流行毒株。我们将使用的策略是基于最近的一项发现，即流感血凝素蛋白中有一个区域不会突变，可以产生抗体，中和许多不同的流感病毒。我们将分离血凝素蛋白的这一区域，并将其移植到已知能诱导非常有效的免疫反应的载体颗粒上。

DESCRIPTION (provided by applicant): Influenza viruses cause significant morbidity and mortality every year. Vaccines that protect from influenza virus infection are available but they have to be re-formulated annually because their effectiveness is limited to seasonal strains. The high mutation rate of influenza virus, specifically the highly variable antigenic structure of the viral surface protein hemagglutinin (HA) is at the core of this problem. The influenza virus vaccine is reliant on an antibody response to HA and vaccines are manufactured based on predictions of which strains are the most likely to circulate in a given season. These predictions can be inaccurate, leading to ineffective vaccines. Moreover, they do not account for the emergence of pandemic strains as exemplified by the H1N1 "swine flu" outbreak in 2009. Annual vaccination campaigns are also costly and there is increasing resistance to vaccination in a significant segment of the population. A universal influenza virus vaccine that affords lifetime protection against seasonal and pandemic strains would be a solution to these problems. We propose a novel strategy to develop such a universal influenza virus vaccine. The strategy is based on the recent discovery of a broadly neutralizing epitope in the influenza HA. We plan to graft this epitope onto the surface of a virus-like particle (VLP) platform that is based on the insect virus Flock House virus (FHV). FHV VLPs allow presentation of foreign epitopes in a polyvalent manner and induce a potent antibody response. Chimeric FHV particles displaying the HA epitope will be structurally characterized by cryoEM and image reconstruction as well as binding assays using the broadly neutralizing monoclonal antibodies. The particles will then be used to vaccinate mice and their antibody response will be characterized by ELISA and microneutralization assays. It is expected that immunized mice generate neutralizing antibodies and this will be confirmed by challenge studies with live virus. If successful, the proposed research could lead to a transformation in flu vaccination by eliminating the challenges currently associated with this endeavor. PUBLIC HEALTH RELEVANCE: In this application we propose to develop a new influenza virus vaccine that needs to be administered only once and then protects for a lifetime against all seasonal and pandemic strains. The strategy that we will use is based on a recent discovery that there is a region in the influenza hemagglutinin protein that does not mutate and can give rise to antibodies that neutralize many different influenza viruses. We will isolate this region of the hemagglutinin protein and graft it on a carrier particle that is known to induce a very potent immune response.