Virus-like particle vaccines against respiratory syncytial virus

描述(申请人提供)：我们的长期目标是开发一种安全、有效的疫苗来预防呼吸道合胞病毒(RSV)疾病。呼吸道合胞病毒是导致毛细支气管炎、病毒性肺炎、呼吸衰竭和婴儿机械通气的主要原因。在美国，它每年导致12万名婴儿住院，是婴儿病毒性死亡的主要原因。在老年人中，呼吸道合胞病毒导致三分之一的肺炎住院。在儿童和成人中，呼吸道合胞病毒感染是哮喘急性加重的主要原因。目前还没有获得许可的疫苗。实验中的RSV疫苗包括灭活疫苗、减毒活疫苗、亚单位疫苗、病毒载体疫苗和DNA疫苗，并已在动物模型和小型临床试验中进行了测试。然而，这些努力在很大程度上没有成功。灭活疫苗和亚单位疫苗有引起免疫病理的历史。RSV减毒活疫苗是安全的。然而，与野生型RSV一样，减毒RSV具有诱导瞬时/弱免疫的特点。 我们正在开发新型病毒样颗粒(VLP)RSV疫苗。VLP是一种经过基因工程的蛋白质复合体，其结构类似于病毒，缺乏病毒遗传物质，因此无法复制。以VLP形式呈现的病毒蛋白具有高度的免疫原性，并诱导保护性体液、细胞和粘膜免疫反应。我们有在VLP上表达病毒蛋白和评估VLP诱导免疫的丰富经验。RSV融合蛋白(F)和附着糖蛋白(G)包含所有已知的中和抗体表位和几个T细胞表位。我们推测，表达RSV F和G表面或同时表达F和G表面的VLP将诱导强烈的RSV特异性免疫反应和免疫。 在目标1中，我们将利用重组杆状病毒系统在昆虫细胞中表达VLP蛋白，并通过梯度超速离心法纯化VLP。我们在这些方法方面有经验，这些方法是FDA批准用于人类使用的，并可扩展用于生产。我们将以流感基质M1蛋白为VLP核心，通过共表达这些蛋白产生RSV-G、RSV-F和RSV-GF VLP。共表达粒细胞-巨噬细胞集落刺激因子(GM-CSF)蛋白的VLP表现出增强的细胞和体液反应。我们将在有或没有锚定GM-CSF的情况下产生RSV VLP。此外，我们还将通过测试三种不同的联合给药佐剂来优化免疫原性：氢氧化铝(明胶)、CpG寡核苷酸(CpG ODN)和单磷脂(MPL)。后两种佐剂刺激Toll样受体信号通路，已知对抗RSV反应很重要。在目标2中，我们将在小鼠模型中确定这些RSV VLP疫苗的免疫原性和效力。小鼠将接受VLP鼻腔注射和增强。RSV特异性抗体(Ig G和Ig A)和T细胞反应将在免疫后进行量化。为了确定保护作用，我们将用一种重组嵌合RSV毒株挑战小鼠，已知该毒株在BALB/c小鼠身上具有比实验室RSV毒株更高的肺部病毒载量。总的来说，这些实验将推进RSV VLP疫苗的开发，并可能导致亟需的批准的RSV疫苗。 公共卫生相关性：呼吸道合胞病毒(RSV)在美国每年导致大约12万名婴儿住院，是毛细支气管炎和婴儿病毒性死亡的主要原因。尽管对传统疫苗方法进行了数十年的研究，但还没有批准的RSV疫苗。我们正在开发RSV的病毒样颗粒(VLP)疫苗，我们预测RSV VLP将是预防RSV疾病的有效和安全的疫苗。

DESCRIPTION (provided by applicant): Our long term goal is to develop a safe, effective vaccine to prevent respiratory syncytial virus (RSV) disease. RSV is the leading cause of bronchiolitis, viral pneumonia, respiratory failure, and mechanical ventilation in infants. It causes >120,000 infant hospitalizations per year in the USA and is the leading cause of infant viral death. In the elderly, RSV causes one third of pneumonia hospitalizations. In children and adults, RSV infection is a major cause of acute asthma exacerbations. There is no licensed vaccine. Experimental RSV vaccines including inactivated, live attenuated, subunit, viral-vectored, and DNA have been developed and tested in animal models and small clinical trials. However, these have been largely unsuccessful. Inactivated and subunit vaccines have a history of causing immunopathology. Live attenuated RSV vaccines are safe. However, attenuated RSVs characteristically induce transient/poor immunity like wild-type RSV. We are developing novel virus-like particle (VLP) RSV vaccines. VLPs are genetically engineered complexes of proteins in a particulate virus-like structure that lacks viral genetic material and therefore cannot replicate. Viral proteins presented as VLPs are highly immunogenic and induce protective humoral, cellular, and mucosal immune responses. We have extensive experience expressing viral proteins on VLPs and evaluating VLP-induced immunity. The RSV fusion (F) and attachment glycoprotein (G) contain all known neutralizing antibody epitopes and several T cell epitopes. We hypothesize that VLPs expressing RSV F, G, or both F and G surface will induce strong RSV-specific immune responses and immunity. In Aim 1, we will generate VLPs using a recombinant baculovirus system to express VLP proteins in insect cells and gradient ultracentrifugation to purify VLPs. We have experience with these methods which are FDA approved for human use and scalable for production. We will generate RSV-G, RSV-F, and RSV-GF VLPs by co-expressing these proteins with influenza matrix M1 protein as the VLP core. VLPs co-expressing granulocyte-macrophage colony-stimulating factor (GM-CSF) proteins exhibit enhanced cellular and humoral responses. We will generate RSV VLPs with and without anchored GM-CSF. Also, we will optimize immunogenicity by testing three different co-administered adjuvants, aluminum hydroxide (alum), CpG oligodeoxynucleotides (CpG ODN), and monophosphoryl lipid (MPL). The latter two adjuvants stimulate toll- like receptor signaling pathways known to be important for anti-RSV responses. In Aim 2, we will define the immunogenicity and efficacy of these RSV VLP vaccines in a mouse model. Mice will be primed and boosted with VLPs intranasally. RSV-specific antibody (IgG and IgA) and T cell responses will be quantified after immunization. To determine protection, we will challenge mice with a recombinant, chimeric RSV strain known to give higher lung viral loads than laboratory RSV strain in BALB/c mice. Collectively, these experiments will advance RSV VLP vaccine development and may lead to a much needed approved RSV vaccine. PUBLIC HEALTH RELEVANCE: Respiratory syncytial virus (RSV) causes apprimately 120,000 infant hospitalizations in the US each year and is the leading cause of bronchiolitis and viral death in infants. Despite decades of research with traditional vaccine approaches, there are no approved RSV vaccines. We are advancing virus-like particle (VLP) vaccines for RSV, and we predict RSV VLPs will be effective and safe vaccines that prevent RSV disease.