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

描述(申请人提供)：由新型猪源甲型H1N1流感病毒(S-OIV)引起的甲型流感最近在全球范围内爆发，导致人们越来越关注高致病性禽流感H5N1病毒的大流行潜力，因为目前获得许可的季节性流感疫苗未能对新出现的甲型流感病毒产生交叉保护作用。因此，迫切需要开发一种安全有效的疫苗来对抗不同的IAV，特别是那些导致当前和未来流感大流行的IAV。我们和其他人已经报道，基质蛋白2的胞外区(M2e)和血凝素-2(HA2)的融合肽(FP)含有高度保守的表位，可以诱导强大的体液和细胞免疫反应，并对IAV具有广泛的保护作用。我们的初步研究还表明，将重组HA蛋白与Ig G的Fc片段融合作为免疫增强剂，可以诱导出较强的交叉中和抗体反应，并对各种H5N1病毒株产生交叉保护。因此，我们推测，含有M2e和FP高度保守表位的重组蛋白与Fc融合后，可能会诱导强大的体液和细胞免疫反应，包括中和抗体，并诱导对不同的IAV的交叉保护，包括当前流行的H1N1和HPAI H5N1毒株，以及其他可能导致未来大流行的分离株。这项建议的具体目的是：(1)设计一种含有IAV M2e和FP保守表位的流感疫苗(M2e-FP)与Fc免疫增强剂(M2e-FP-Fc)融合，并以M2e-FP、Fp-Fc和M2e-Fc为对照；(2)用这些抗原单独或联合(如M2e-Fp-Fc+Fp-Fc)免疫小鼠和兔子，并评估免疫动物中特异性的体液和细胞免疫反应和中和抗体；(3)在免疫小鼠模型中评价对IAV攻击的体内保护性免疫。这项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IAV。 公共卫生相关性：目前的H1N1流感大流行(俗称“猪流感”)以及未来可能爆发的H5N1流感对全球公共卫生构成严重威胁。这项拟议研究的目标是根据甲型流感病毒表面蛋白与分子相连的保守序列设计和开发一种“通用”疫苗，以增强抗原的免疫原性，这种流感疫苗有望在未来有效和安全地供人类使用，以预防流感流行。

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.