Broadly Specific Needle-Free Vaccines against Emerging and Biothreat Viruses

描述(由申请人提供)：埃博拉丝状病毒(EBOV)和马尔堡丝状病毒(Marburg)疫苗的开发因这些病毒的多个物种和毒株同时传播而受阻，包括那些没有或具有有限抗原性的病毒。目前正在开发的候选疫苗包括作为丝状病毒主要保护性抗原的GP蛋白。这些候选人中的每一个都有严重的局限性。这些问题包括需要非常高或多次的剂量进行保护，在存在媒介特异性抗体的情况下缺乏免疫原性，媒介的潜在毒力，生产成本高，以及缺乏可行的无针给药技术。此外，最重要的是 现有候选疫苗的局限性在于，它们都需要多种成分来防御个别种类的丝状病毒，而且它们对目前未确定的物种或毒株的保护程度尚不清楚，这些物种或毒株将在未来出现，与已知物种的抗原性有限。我们以前的数据表明，以表达EBOV gP的减毒呼吸道副粘病毒为基础的载体对豚鼠和非人类灵长类动物(NHP)的粘膜呼吸道免疫可诱导强大的血清EBOV中和抗体反应，使动物对高致死量EBOV腹腔攻击具有“灭菌”免疫力，并在呼吸道诱导粘膜抗体反应。最近开发针对H5N1高致病性禽流感病毒的单组分疫苗的突破性方法是基于从多个病毒产生的共识、祖先或计算优化的广谱反应抗原(COBRA)序列，该序列对没有或有限抗原相关性的多个不同的病毒分支具有保护作用。此外，过去对流感病毒的研究表明，经粘膜而不是肠外注射流感疫苗可诱导粘膜免疫球蛋白和免疫球蛋白A与血清免疫球蛋白产生交叉反应，并可诱导B细胞对抗原性不同的异型流感病毒的保护作用。该建议包括开发一种广泛特异的泛丝病毒疫苗，该疫苗基于EBOV和MARV的祖传、共识或COBRA GP蛋白，由减毒的呼吸道副粘病毒表达，通过呼吸道粘膜给药将进一步增强其保护范围，并将对目前和未来传播的所有丝状病毒具有保护作用。具体的 目标如下：(1)通过获得EBOV或MARV的祖先蛋白、共识蛋白或COBRA GP蛋白，开发和测试能够诱导针对这两种病毒的多价反应的单一疫苗组件；(2)提高疫苗的免疫原性和保护效力，并通过选择最有效的载体变异体、优化剂量和疫苗接种方案，最大限度地减少诱导保护性免疫反应所需的时间；(3)分析免疫接种的系统和局部免疫反应，以确定临床试验的有效保护相关性。

DESCRIPTION (provided by applicant): Development of a vaccine against the filoviruses Ebola (EBOV) and Marburg (MARV) is hindered by the simultaneous circulation of multiple species and strains of these viruses, including those with no or limited antigenic relatedness. Vaccine candidates currently in development include the GP protein as the major protective antigen of filoviruses. Each of these candidates has severe limitations. These include the need for very high or multiple doses for protection, the lack of immunogenicity in the presence of vector-specific antibodies, the potential virulence of vectors, high cost of production, and the lack of feasible technologies for their needle-free administration. In addition, the most important limitations of the existing vaccine candidates is that they all require multiple components to protect against individual species of filoviruses, and their unclear level of protection against currently unidentified species or strains which will appear in the future and have a limited antigenic relatedness to the known species. Our previous data demonstrate that mucosal respiratory tract immunization of guinea pigs and non-human primates (NHP) with vectors based on attenuated respiratory paramyxoviruses expressing EBOV GP induces a robust serum EBOV-neutralizing antibody response; confers to the animals "sterilizing" immunity against intraperitoneal challenge with a highly lethal dose of EBOV; and induces mucosal antibody response in the respiratory tract. Recent breakthrough approaches for development of single-component vaccines against the H5N1 highly pathogenic avian influenza viruses were based on the generation of consensus, ancestral or Computationally-Optimized Broadly Reactive Antigen (COBRA) sequences derived from multiple viruses, which conferred protection against multiple diverse clades of the virus with no or limited antigenic relatedness. Moreover, a past study with influenza virus demonstrated that a mucosal, but not parenteral delivery of an influenza vaccine induced cross-reactive mucosal IgG and IgA and serum IgG, and B-cell dependent protection against antigenically different heterosubtypic influenza viruses. The proposal includes development of a broadly specific, pan-filovirus vaccine based on ancestral, consensus, or COBRA GP proteins of EBOV and MARV, expressed by attenuated respiratory paramyxoviruses, whose breadth of protection will be further enhanced by their mucosal administration through the respiratory tract, and which will be protective against all filoviruses that circulate at the present time as well as those that will circulate in the future. The Specific Aims are the following: (1) Develop and test single vaccine components capable of inducing multivalent responses against EBOV or MARV by deriving ancestral, consensus, or COBRA GP proteins for each of the two viruses; (2) Improve immunogenicity and protective efficacy of the vaccine, and minimize time required for induction of the protective immune response by selecting the most potent vector variants and optimizing dosage and the vaccination regimen; (3) Analyze the systemic and local immune responses to immunizations to determine valid correlates of protection for clinical trials.