Rational design of M2e-FP conserved epitope-based universal influenza A vaccines

描述（由申请方提供）：最近由新型猪源H1N1甲型流感病毒（S-OIV）引起的甲型流感全球爆发，导致人们越来越关注高致病性禽流感（HPAI）H5 N1病毒的大流行潜力，因为目前许可的季节性流感疫苗无法对新出现的甲型流感病毒（IAV）产生交叉保护。因此，迫切需要开发针对不同IAV，特别是引起当前和未来流感大流行的IAV的安全有效的疫苗。我们和其他人报道了含有高度保守表位的基质蛋白2（M2 e）的胞外结构域和血凝素-2（HA 2）的融合肽（FP）可以诱导强烈的体液和细胞免疫应答以及广泛的抗IAV保护。我们的初步研究还表明，与IgG的Fc片段融合的重组HA蛋白作为免疫增强剂可以诱导针对各种H5 N1病毒株的强烈的交叉中和抗体应答和交叉保护。因此，我们假设，含有M2 e和FP中高度保守的表位融合到Fc的重组蛋白可能会引发有效的体液和细胞免疫应答，包括中和抗体，并诱导针对不同IAV的交叉保护，包括当前流行的H1N1和HPAI H5 N1毒株，以及可能导致未来大流行的其他分离株。本提案的具体目的是：（1）设计含有IAV的M2 e和FP中的保守表位（M2 e-FP）与Fc免疫增强剂（M2 e-FP-Fc）融合的流感疫苗，并使用M2 e-FP、FP-Fc和M2 e-Fc作为对照;（2）用这些抗原单独或组合（例如，M2 e-FP-Fc + FP-Fc），并评估免疫动物的特异性体液和细胞免疫应答以及中和抗体;（3）评估免疫小鼠模型对IAV攻击的体内保护性免疫。拟议研究的长期目标是开发一种针对不同IAV的通用甲型流感疫苗，包括那些导致未来流感大流行的疫苗。 公共卫生相关性：目前的H1N1流感大流行（俗称“猪流感”）和未来可能爆发的H5 N1流感对全球公共卫生构成严重威胁。这项拟议研究的目的是设计和开发一种基于病毒表面蛋白保守序列的甲型流感病毒“通用”疫苗，该疫苗与一种分子连接，以增强抗原的免疫原性，预计这种流感疫苗将来可有效和安全地用于人类预防流感流行。

DESCRIPTION (provided by applicant): The recent global outbreak of influenza A caused by a novel swine-origin H1N1 influenza A virus (S-OIV) has led to a growing concern regarding the pandemic potential of the highly pathogenic avian influenza (HPAI) H5N1 viruses because the currently licensed seasonal influenza vaccines fail to produce cross-protection against the newly emerging influenza A viruses (IAVs). Therefore, development of a safe and effective vaccine against divergent IAVs, especially those causing current and future influenza pandemics, is urgently needed. We and others have reported that the extracellular domain of matrix protein 2 (M2e) and the fusion peptide (FP) of the hemagglutinin-2 (HA2) that contain highly conserved epitopes can induce strong humoral and cellular immune responses and broad protection against IAVs. Our preliminary studies also showed that the recombinant HA protein fused to Fc fragment of IgG as an immune enhancer could induce strong cross-neutralizing antibody responses and cross- protection against various strains of H5N1 viruses. We thus hypothesize that a recombinant protein containing the highly conserved epitopes in M2e and FP fused to Fc may elicit potent humoral and cellular immune responses, including the neutralizing antibodies, and induce cross-protection against divergent IAVs, including current epidemic H1N1 and HPAI H5N1 strains, and other isolates that might cause future pandemics. The specific aims of this proposal are: (1) to design an influenza vaccine containing conserved epitopes in M2e and FP of IAV (M2e-FP) fused with Fc immune enhancer (M2e-FP-Fc) and use M2e-FP, FP-Fc and M2e-Fc as controls; (2) to immunize mice and rabbits with these antigens, alone or in combination (e.g., M2e-FP-Fc + FP-Fc), and to assess specific humoral and cellular immune responses and neutralizing antibodies in the vaccinated animals; (3) to evaluate the in vivo protective immunity against IAV challenge in the immunized mouse models. The long-term goal of the proposed study is to develop a universal influenza A vaccine against divergent IAVs, including those causing future influenza pandemics. PUBLIC HEALTH RELEVANCE: The current H1N1 influenza pandemic (commonly known as the "swine flu") and the potential outbreak of H5N1 influenza in the future pose serious threats to public health worldwide. The goal of this proposed study is to design and develop a "universal" vaccine for influenza A viruses based on the conserved sequences of viral surface proteins linked with a molecule to enhance immunogenicity of the antigens and this influenza vaccine is expected to be effective and safe for human use for preventing influenza epidemics in the future.