Respiratory Syncytial Virus G proteins to improve safety/efficacy of vaccines

 描述(申请人提供)：呼吸道合胞病毒(RSV)感染几乎所有2岁以下的儿童，是全球幼儿严重下呼吸道疾病的主要原因。然后，RSV会导致反复感染，这种感染可能会严重并危及生命。据估计，RSV每年导致全球16万人死亡，在美国，5岁以下儿童住院治疗多达15万人。呼吸道合胞病毒疾病的负担导致人们正在为幼小的呼吸道合胞病毒幼稚儿童和接种了合胞病毒的较大儿童和成年人开发合胞病毒疫苗。第一个RSV疫苗，福尔马林灭活的RSV明胶佐剂(FI-RSV)，导致更严重的疾病，后来自然感染。FI-RSV增强型疾病的经历引起了人们对RSV幼稚儿童的任何非活病毒疫苗的担忧。因此，该领域已经为幼儿开发了减毒活疫苗，而为RSV免疫的较大儿童和成年人寻求了多种方法，包括灭活疫苗和亚单位疫苗。然而，尽管进行了50多年的研究，仍没有疫苗可用。未能开发出有效的疫苗表明，需要新的方法和对现有疫苗的改进。这项提议的目标是开发可被纳入现有或新疫苗中的G蛋白，以提高其安全性和有效性。提出这一建议的理由是：1)自然感染和注射高滴度的RSV中和抗体仅提供了对疾病的部分保护，2)G蛋白诱导了导致疾病的宿主反应，以及3)结合G与抗体可以预防大部分G相关疾病。G蛋白是两种RSV蛋白之一，被证明可以诱导保护性免疫反应，大多数疫苗都专注于诱导与F蛋白结合的中和抗体。由于针对G中央保守区(CCR-G)的抗体在不减少病毒复制的情况下减少了动物的疾病，我们假设G蛋白构建专门用于增加抗CCR-G抗体的水平将消除疾病增强反应，使疫苗更安全和更有效。由于Ccr-G也是最保守的区域，它是G区域中最适合诱导免疫的区域，可以跨不同的RSV毒株进行保护。CCR-G确实包含与疾病相关的氨基酸序列，但这些序列将被突变，以确保安全性。我们建议通过两个目的来制备和测试各种G蛋白结构，并鉴定出1或2个能够诱导高滴度抗CCR-G抗体，减少以后感染的疾病，并可用于亚单位和/或活病毒疫苗平台的G蛋白结构：目的1：鉴定能够诱导高滴度抗CCR-G抗体的G蛋白结构，并在RSV攻击的小鼠中减少疾病。目的2：在小鼠模型中检测G修饰的活RSVs的疫苗潜能。

 DESCRIPTION (provided by applicant): Respiratory syncytial virus (RSV) infects nearly all children by 2 years of age and the leading cause of serious lower respiratory tract disease in young children worldwide. RSV then causes repeat infections that can be serous and life threatening throughout life. It is estimated that RSV leads to 160,000 deaths each year globally and up to 150,000 hospitalizations in the United States in children <5 years of age. The burden of RSV disease has led RSV vaccines are being developed for the young RSV naïve child and RSV primed older children and adults. The first RSV vaccine, formalin-inactivated RSV with alum adjuvant (FI-RSV), led to more severe disease with later natural infection. The experience of FI-RSV enhanced disease has generated concern for any non-live virus vaccine in RSV naïve children. Therefore, the field has developed live- attenuated vaccines for young children whereas multiple approaches, including inactivated and subunit vaccines, are pursued for RSV primed older children and adults. Despite over 50 years of research, however, no vaccine is available. The failure to develop an effective vaccine suggests that novel approaches and improvements to existing vaccines are needed. The goal of this proposal is to develop G proteins that can be incorporated into existing or new vaccines to improve their safety and efficacy. The rationale for this proposal follows from the fact that 1) natural infection and administration of high titer of RSV neutralizing antibodies provides only partial protection from disease, 2) the G protein induces host responses that contribute to disease, and 3) binding G with antibodies can prevent much of the G-associated disease. The G protein is one of two RSV proteins shown to induce protective immune responses and most vaccines have focused on induced neutralizing antibodies with the F protein. Since antibodies against the central conserved region of G (CCR-G) decrease disease in animals without decreasing virus replication, we hypothesize that G protein constructs specifically designed to increase the level of anti-CCR-G antibodies will eliminate disease enhancing responses and make a vaccine safer and more effective. Since CCR-G is also the most conserved region, it is the region in G best suited to elicit immunity that protects across different RSV strains. The CCR-G does contain amino acid sequences associated with disease but these sequences will be mutated to ensure safety. We propose to make and test a variety of G protein constructs and identify 1 or 2 that induce high titer of anti-CCR-G antibodies, decrease disease with later infection, and can be used in subunit and/or live virus vaccine platforms through two aims: Aim 1: Identify G protein constructs that induce high titers of anti-CCR-G antibodies and decrease disease in RSV-challenged mice after vaccination. Aim 2: Test the vaccine potential of G-modified live RSVs in a mouse model.