Mechanisms of Enhanced Neutralizing Antibody Responses to Rhinovirus C

项目概要： 鼻病毒（Rhinovirus，RV）是引起普通感冒的主要原因，是病毒诱导的 哮喘急性发作和伴有RV感染喘息的婴儿发生哮喘的风险增加。 在三种RV种类（A、B和C）中，RV-C是喘息性疾病和呼吸道感染加重的主要原因。 儿童哮喘与血清学表征的RV-A和B相反，RV-C的当前分类 是完全基于VP 1区的序列同一性，以及这些基因型是否对应于独特的 血清型未知。CDHR 3基因单核苷酸多态性（SNP，rs6967330）儿童， 编码RV-C的细胞受体的人是RV-C感染和疾病的最大风险。这种编码SNP 也是儿童哮喘早发的危险因素。目前还没有特异性的抗病毒药物或疫苗可用于治疗 和预防RV-C引起的疾病，但接种疫苗以预防RV感染（特别是RV-C， 携带CDHR 3 SNP的幼儿）可能会对公共卫生产生重大影响。我们最近在动物模型上的研究 已经证明了多价灭活RV疫苗抗原的可行性。与RV相关的新发现- C结构、自然获得性免疫和人单克隆抗体的生产将有助于我们填补现有的 知识差距，并开发适合临床试验的RV-C疫苗方法。很少有人知道的 对RV-C的中和抗体应答的机制。绘制了RV-A和RV-B的中和表位 到衣壳蛋白最突出的表面突起。有趣的是，第一个低温电磁原子结构的 RV-C显示独特的突出的“指状”刺突，由VP 1形成，预测为显性免疫原性 表位我们将测试这些衣壳结构中的类型特异性和交叉反应性表位。最近的另一 一项新的发现是，对RV-C的体液免疫（与其他RV相比）随着年龄的增长而更快地获得。我们 假设RV-C感染可诱导更强、交叉反应性更强的中和抗体应答， 与RV-A相比，持续时间更长，原因是（i）它们能够在幼儿中诱发更严重的疾病， 和（ii）主要中和免疫原性表位中的一些关键结构和/或功能差异。测试 基于这一假设，我们提出了三个具体目标：1）确定中和抗体的宿主和病毒决定簇 结合来自多个队列研究（n=14）的RV分型数据和滴度分析的应答， COAST儿童中这些抗体反应的出现和持续时间; 2）确定RV-C是否 基因型代表独特的血清型或共享共同的表位; 3）使用人单克隆抗体 与RV-C复合，绘制主要免疫原性表位并确定RV-C抗体的机制 通过冷冻EM进行中和和交叉中和。这些研究将为制定一个广泛的 保护性RV-C疫苗可能对RV-C诱导风险增加的幼儿有显著益处 下呼吸道感染

PROJECT SUMMARY: Rhinovirus (RV) is the predominant cause of the common cold, a major contributor to virus-induced exacerbations of asthma, and infants who wheeze with RV infections are at increased risk for developing asthma. Of the three RV species (A, B and C), RV-C is a major contributor to wheezing illnesses and exacerbations of asthma in young children. In contrast to serologically characterized RV-A and B, current classification of RV-C is based solely on sequence identity in the VP1 region and whether these genotypes correspond to unique serotypes is unknown. Children with a single nucleotide polymorphism (SNP, rs6967330) in CDHR3 gene, encoding the cellular receptor for RV-C, are at greatest risk for RV-C infections and illnesses. This coding SNP is also a risk factor for early onset childhood asthma. There are no specific antivirals or vaccines for treatment and prevention of RV-C induced illnesses but vaccination to prevent RV infections (and particularly RV-C in young children with the CDHR3 SNP) could have major public health impact. Our recent studies in animal models have demonstrated the feasibility of polyvalent inactivated RV vaccine antigens. New discoveries related to RV- C structure, naturally-acquired immunity and human monoclonal antibody production will help us to fill existing knowledge gaps and develop RV-C vaccine approaches suitable for clinical trials. Little is known about the mechanisms of neutralizing antibody responses to RV-C. Neutralizing epitopes for RV-A and RV-B were mapped to the most prominent surface protrusions of capsid proteins. Interestingly, the first cryo-EM atomic structure of RV-C revealed unique, protruding “finger-like” spikes, formed by VP1, predicted to be dominant immunogenic epitopes. We will test for type-specific and cross-reactive epitopes in these capsid structures. Another recent discovery is that humoral immunity to RV-C (compared to other RVs) is more rapidly acquired with age. We hypothesize that infections with RV-C can induce stronger, more cross-reactive neutralizing antibody responses of longer duration compared to RV-A, due to (i) their ability to induce more severe illnesses in young children, and (ii) some key structural and/or functional differences in major neutralizing immunogenic epitopes. To test this hypothesis, we propose three specific aims: 1) to identify host and viral determinants of neutralizing antibody responses combining the RV typing data from multiple cohort studies (n=14) and analysis of titers, time of appearance and duration of these antibody responses in the COAST children; 2) to determine whether RV-C genotypes represent unique serotypes or share common epitopes; 3) using human monoclonal antibodies complexed with RV-C, map major immunogenic epitopes and determine the mechanisms of RV-C antibody neutralization and cross-neutralization by cryo-EM. These studies will inform the development of a broadly protective RV-C vaccine that could be of significant benefit to young children at increased risk for RV-C induced lower respiratory tract infections.