Adenoviral Vector-based Pandemic Influenza Vaccine

描述(由申请人提供)：甲型流感病毒(IFV)仍然是一个严重的全球公共卫生问题。在美国，每年有2万到4万人死于IFV。由于自然发生的抗原转变或由于生物恐怖主义而引入新的抗原亚型，可能会导致一场具有毁灭性后果的大流行。目前可用的灭活IFV疫苗和亚单位IFV疫苗对流感大流行株的成功有限。下一次流感大流行可能在任何时候发生，而且几乎没有警告。最近在人类中出现的H5N1、H7N7和H9N2型禽流感病毒突显了至少一些禽流感亚型跨越物种障碍进入人类的能力。此类事件可通过出现能够在幼稚人群中迅速传播的人-禽重组病毒而导致流感的大流行暴发。 众所周知，腺病毒载体可以激活先天免疫，并可通过粘膜或肠外途径给药。一般来说，腺病毒载体是体液免疫(包括粘膜免疫)和细胞免疫(CMI)的强诱导因子。在特定目标1下，将发展表达H5N1的血凝素(HA)、核蛋白(NP)或基质蛋白2(M2)的腺病毒载体，并在小鼠模型中评价其诱导体液和CMI反应的能力以及对IFV攻击的保护程度。NP和M2蛋白在IFV亚型中相对保守，诱导良好的细胞免疫，从而拓宽了对流感的免疫应答范围。防御素是由Toll样受体激活诱导的小分子蛋白质，可以招募炎性细胞并放大先天和获得性免疫反应。用纯化的H5N1病毒HA免疫研究表明，该HA具有较低的免疫原性，因此，用腺病毒载体表达的禽流感病毒(H5N1、H7N7和H9N2)的HA免疫原性可以通过表达防御素的腺病毒载体进一步增强。在特定目标2下，将评估通过顺序注射非人腺病毒载体和人腺病毒载体，利用表达新型HA或HA、NP和M2的腺病毒载体的组合，以及在有或没有防御素的情况下，发展持久和广泛的IFV免疫的策略。幼稚的近交系小鼠和近交系的雪貂将被用于免疫和挑战试验，以解决人类可能存在的复杂的免疫谱。该项目的成功完成将促进我们对有效预防大流行IFV所需的持久和广泛免疫所需的免疫和免疫原类型/S的了解。

DESCRIPTION (provided by applicant): Influenza virus A (IFV) continues to be a significant public health problem worldwide. Between 20,000 and 40,000 deaths are attributed to IFV every year in the United States. Introduction of a new antigenic subtype either due to naturally occurring antigenic shift or by bioterrorism could lead to a pandemic with devastating consequences. The currently available killed and subunit IFV vaccines will have only limited success against pandemic strains of influenza. The next influenza pandemic could occur at any time and with little warning. The recent emergence of avian influenza H5N1, H7N7 and H9N2 viruses in humans has highlighted the ability of at least some avian subtypes to cross the species barrier into humans. Such events can cause pandemic outbreaks of influenza by the emergence of an avian-human reassortant virus with the ability to spread rapidly in a naive human population. Adenoviral vectors are known to activate innate immunity and can be administered via the mucosal or parenteral route. In general, adenoviral vectors are strong inducers of both humoral (including mucosal) and cell-mediated immunity (CMI). Under Specific Aim 1, adenoviral vectors expressing hemagglutinin (HA), nucleoprotein (NP), or matrix protein 2 (M2) from H5N1 or HA from H7N7 or H9N2 will be developed and evaluated for their ability to induce humoral and CMI responses and degree of protection to IFV challenge in a mouse model. NP and M2 proteins are relatively conserved among IFV subtypes and induce good cellular immunity, thus broadening the scope of immune responses against influenza. Defensins, small molecular weight proteins induced by toll-like receptor activation, can recruit inflammatory cells and amplify innate and adaptive immune responses. Immunization studies with purified HA of H5N 1 virus indicate that this HA is poorly immunogenic, therefore, the immunogenicity of HA of avian IFVs (H5N 1, H7N7 and H9N2) expressed by adenoviral vectors could be further enhanced by the use of adenoviral vectors expressing defensin. Under Specific Aim 2, the strategies for developing long-lasting and broad IFV immunity with a combination of adenoviral vectors expressing novel HA types or HA, NP, and M2 with or without defensin by sequential administration of nonhuman and human adenoviral vectors will be evaluated. Naive and primed inbred mice and outbred ferrets will be used for immunization and challenge trials to address the complex spectrum of immunity that would exist in humans. The successful completion of this project will advance our understanding towards the type of immunity and immunogen/s required for long-lasting and broad immunity for effective protection against pandemic IFV.