Development of a broadly neutralizing influenza virus vaccine

描述（由申请人提供）：流感病毒每年都会造成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）的高度可变抗原结构是这一问题的核心。流感病毒疫苗依赖于对血凝素的抗体反应，而疫苗的生产是基于对在特定季节哪种毒株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”爆发所代表的大流行毒株的出现。每年的疫苗接种运动也很昂贵，而且在很大一部分人口中，对疫苗接种的抵抗力越来越强。一种通用流感病毒疫苗，提供对季节性和大流行毒株的终身保护，将是解决这些问题的办法。我们提出了一种开发这种通用流感病毒疫苗的新策略。该策略是基于最近在流感HA中发现的广泛中和表位。我们计划将该抗原表位移植到基于昆虫病毒禽舍病毒（FHV）的病毒样颗粒（VLP）平台表面。FHV VLPs允许外源表位以多价方式呈现，并诱导有效的抗体反应。显示HA表位的嵌合FHV颗粒将通过低温电镜和图像重建以及使用广泛中和的单克隆抗体的结合试验进行结构表征。然后，这些颗粒将用于给小鼠接种疫苗，它们的抗体反应将通过酶联免疫吸附试验和微量中和试验来表征。预计免疫小鼠产生中和抗体，这将通过活病毒攻击研究得到证实。如果成功，这项研究将消除目前与流感疫苗接种相关的挑战，从而导致流感疫苗接种的转变。

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.