Adenoviral Vector-based Pandemic Influenza Vaccine

描述（由申请方提供）：甲型流感病毒（IFV）仍然是全球重大的公共卫生问题。在美国，每年有2万至4万人死于IFV。由于自然发生的抗原转变或生物恐怖主义而引入新的抗原亚型可能导致具有破坏性后果的大流行。目前可用的灭活和亚单位IFV疫苗对流感大流行株的成功率有限。下一次流感大流行可能在任何时候发生，而且几乎没有预警。最近在人类中出现的禽流感H5 N1、H7 N7和H9 N2病毒突出了至少一些禽类亚型跨越物种屏障进入人类的能力。此类事件可通过出现具有在未感染人群中快速传播能力的禽-人应答病毒而引起流感大流行暴发。 已知腺病毒载体可激活先天免疫，并可通过粘膜或肠胃外途径给药。一般而言，腺病毒载体是体液（包括粘膜）和细胞介导的免疫（CMI）的强诱导剂。在特定目标1下，将开发表达来自H5 N1的血凝素（HA）、核蛋白（NP）或基质蛋白2（M2）或来自H7 N7或H9 N2的HA的腺病毒载体，并评价其在小鼠模型中诱导体液和CMI应答的能力以及对IFV攻击的保护程度。NP和M2蛋白在IFV亚型中相对保守，并诱导良好的细胞免疫，从而拓宽了针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量蛋白质，可以募集炎性细胞并增强先天性和适应性免疫反应。用纯化的H5 N1病毒HA免疫研究表明，该HA的免疫原性差，因此，腺病毒载体表达的禽IFV（H5 N1、H7 N7和H9 N2）的HA的免疫原性可通过使用表达防御素的腺病毒载体进一步增强。在具体目标2下，将评价通过非人和人腺病毒载体的顺序施用，用表达新型HA类型或HA、NP和M2的腺病毒载体与或不与防御素的组合来开发持久和广泛的IFV免疫的策略。将使用未经处理和致敏的近交系小鼠和远系繁殖的雪貂进行免疫和攻毒试验，以解决人类中存在的复杂免疫谱。该项目的成功完成将促进我们对有效预防大流行性IFV所需的持久和广泛免疫力的免疫类型和免疫原的理解。

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.