Broad-Range VLP Vaccine Against H5N1 Influenza

描述(申请人提供)：高致病性禽流感(HPAI)病毒是C类NIAID优先病原体和全球生物防御威胁。提供对HPAI病毒的保护的疫苗是生物防御和大流行防备所必需的。在过去十年中，H5N1 HPAI病毒在基因和抗原性上多样化，导致需要多种H5N1疫苗。尽管已经准备好了H5N1分支1疫苗，但它们不太可能预防其他H5N1分支。此外，准备工作 为每一种潜在威胁病毒提供疫苗是昂贵的，在经济上是不可行的，并可能引起严重的生物安全和生物保障问题。重组病毒样颗粒(VLP)是预防HPAI的一种很有前途的策略。VLP在安全性、有效性和制造方面具有优势，因为它们避免了病毒生长缓慢、产量不可预测和宿主适应性突变等问题。已有研究表明，与标准流感疫苗相比，VLP可诱导对不同毒株更广泛的免疫力，特别是在黏膜接种的情况下(Bright等人，2007年；Perrone等人，2009年)。此外，我们最近制备了多亚型VLP，其中几种不同的血凝素亚型(HA)共定位在同一VLP结构中，从而提供了对多种挑战病毒的保护(Pushko等人，2011年；Tretyakova等人，2013年)。多亚型疫苗具有诱导广泛的、但传统的针对几种流感亚型的病毒中和免疫反应的优势。 在这里，我们建议使用多HA VLP平台来开发多H5 VLP作为独特的多分支H5N1 VLP疫苗。多个H5 VLP将被合理地设计为在VLP内共定位来自三个不同H5N1分支的三个H5蛋白。由此产生的三重H5 VLP预计将产生对多种H5N1 HPAI病毒的有效保护，从而产生安全有效、具有广泛保护性的H5N1疫苗。特别是，我们建议制备共定位来自Clade 1、Clade 2.2.1.1和Clade 2.3.2.1病毒的H5蛋白的VLP，这些病毒都是WHO推荐用于H5N1疫苗开发的。将利用重组杆状病毒表达技术制备多个H5 VLP，并对VLP的遗传稳定性、生化、结构和抗原性进行评价(SP。目标1)。将与疾病控制和预防中心(CDC)合作，在实验性雪貂攻击模型中评估三重H5 VLP的免疫原性和有效性。两个同源(Sp.目标2)和异源(Sp.目的3)提出H5N1 HPAI挑战，以评估这种新型广谱H5N1疫苗。幼年和年长的雪貂将被纳入挑战研究，以模仿最脆弱的人类种群。将评估肌肉和鼻腔接种途径对免疫反应的影响。广泛的免疫机制将被阐明，包括体液免疫、细胞免疫和粘膜免疫。将进行工艺开发和技术转移到制造环境中。在完成临床前试验和工艺开发活动后，将计划与FDA举行IND前会议。如果成功，这项新技术可能代表着快速和具有成本效益的多价流感疫苗制备的创新平台，用于生物防御和大流行预防。

DESCRIPTION (provided by applicant): Highly pathogenic avian influenza (HPAI) viruses are Category C NIAID priority pathogens and a global biodefense threat. Vaccines that provide protection against HPAI viruses are required for biodefense and pandemic preparedness. During the past decade, the H5N1 HPAI viruses have diversified genetically and antigenically leading to the need for multiple H5N1 vaccines. Although H5N1 clade 1 vaccines have been prepared, it is unlikely that they will protect against other H5N1 clades. In addition, preparation of vaccines for each potential threat virus is expensive, economically not feasible and can raise serious biosafety and biosecurity concerns. Recombinant virus-like particles (VLPs) represent a promising strategy for prevention of HPAI. VLPs have advantages in safety, efficacy, and manufacturing because they circumvent problems like slow virus growth, unpredictable yields, and host-adaptive mutations. It has been shown that VLPs induce broader immunity against divergent strains than standard influenza vaccines, especially if administered mucosally (Bright et al., 2007; Perrone et al., 2009). Furthermore, we have recently prepared multi-subtype VLP, in which several distinct subtypes of hemagglutinin (HA) were co-localized within the same VLP structure thus providing protection against multiple challenge viruses (Pushko et al., 2011; Tretyakova et al., 2013). The multi-subtype vaccines have advantage of inducing broad-range, yet traditional virus-neutralizing immune responses directed against several influenza subtypes. Here we propose the use of multi-HA VLP platform for the development of multi-H5 VLPs as a unique multi-clade H5N1 VLP vaccine. The multi-H5 VLPs will be rationally designed to co-localize within the VLP the three H5 proteins derived from three distinct H5N1 clades. The resulting triple-H5 VLPs are expected to elicit effective protection against multiple H5N1 HPAI viruses resulting in a safe and effective, broadly protective H5N1 vaccine. Particularly, we propose preparation of VLPs that co-localize H5 proteins derived from Clade 1, Clade 2.2.1.1, and Clade 2.3.2.1 viruses, all recommended by the WHO for H5N1 vaccine development. Multi-H5 VLPs will be prepared by using recombinant baculovirus expression, and genetic stability, biochemical, structural, and antigenic characteristics of VLPs will be evaluated (Sp. Aim 1). Immunogenicity and efficacy of triple-H5 VLPs will be evaluated in experimental ferret challenge model in collaboration with the Centers for Disease Control and Prevention (CDC). Both the homologous (Sp. Aim 2) and heterologous (Sp. Aim 3) H5N1 HPAI challenges are proposed in order to evaluate this novel broad-spectrum H5N1 vaccine. Young and aged ferrets will be included into the challenge studies to mimic the most vulnerable human populations. The effects of intramuscular and intranasal routes of vaccination on immune responses will be evaluated. Mechanisms of broad immunity will be elucidated including humoral, cell-mediated, and mucosal immunity. Process development and technology transfer into manufacturing environment will be carried out. Following completion of preclinical trials and process development activities, a pre-IND meeting with FDA will be planned. If successful, this novel technology may represent an innovative platform for rapid and cost-effective preparation of multivalent influenza vaccines for biodefense and pandemic preparedness.