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

 描述（由申请方提供）：呼吸道合胞病毒（RSV）感染几乎所有2岁以下儿童，是全球幼儿严重下呼吸道疾病的主要原因。RSV然后引起反复感染，这些感染可能是浆液性的，并在整个生命中危及生命。据估计，RSV每年在全球导致160，000例死亡，在美国导致多达150，000例<5岁儿童住院。RSV疾病的负担导致RSV疫苗正在开发用于年轻的RSV初治儿童和RSV致敏的年龄较大的儿童和成人。第一个RSV疫苗，福尔马林灭活的RSV与明矾佐剂（FI-RSV），导致更严重的疾病与后来的自然感染。FI-RSV增强疾病的经验引起了对RSV初治儿童中任何非活病毒疫苗的关注。因此，该领域已经开发了用于幼儿的减毒活疫苗，而对于RSV致敏的较大儿童和成人，则采用多种方法，包括灭活疫苗和亚单位疫苗。然而，尽管经过50多年的研究，仍然没有疫苗可用。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。该提案的目标是开发可以纳入现有或新疫苗的G蛋白，以提高其安全性和有效性。该建议的基本原理来自以下事实：1）自然感染和施用高滴度RSV中和抗体仅提供部分疾病保护，2）G蛋白诱导导致疾病的宿主应答，3）G与抗体结合可预防大部分G相关疾病。G蛋白是显示诱导保护性免疫应答的两种RSV蛋白之一，并且大多数疫苗集中于用F蛋白诱导中和抗体。由于针对G的中央保守区（CCR-G）的抗体在不减少病毒复制的情况下减少动物中的疾病，因此我们假设专门设计用于增加抗CCR-G抗体水平的G蛋白构建体将消除疾病增强反应，并使疫苗更安全和更有效。由于CCR-G也是最保守的区域，因此它是G中最适合引发跨不同RSV毒株保护的免疫的区域。CCR-G确实含有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。我们提出制备和测试多种G蛋白构建体，并鉴定1种或2种诱导高滴度的抗CCR-G抗体，减少后期感染的疾病，并且可以通过两个目的用于亚单位和/或活病毒疫苗平台：目的1：鉴定G蛋白构建体，其诱导高滴度的抗CCR-G抗体，并在接种疫苗后减少RSV攻击的小鼠中的疾病。目的2：在小鼠模型中测试G修饰的活RSV的疫苗潜力。

 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.