Mechanisms of Enhanced Neutralizing Antibody Responses to Rhinovirus C

项目总结： 鼻病毒(RV)是普通感冒的主要原因，也是病毒诱导的主要因素。 哮喘的恶化和患有轮状病毒感染而喘息的婴儿患哮喘的风险更高。 在三种轮状病毒(A、B和C)中，RV-C是引起喘息性疾病和加重的主要因素。 幼儿中的哮喘。与RV-A和B的血清学特征不同，目前的RV-C分类 仅基于VP1区的序列同一性以及这些基因型别是否对应于唯一 血清型尚不清楚。CDHR3基因单核苷酸多态(SNP，rs6967330)儿童 编码RV-C的细胞受体，是RV-C感染和疾病的最大风险。该编码的SNP 也是早发儿童哮喘的危险因素。目前还没有特定的抗病毒药物或疫苗可供治疗 和预防RV-C引起的疾病，但接种疫苗以防止RV感染(特别是RV-C 携带CDHR3SNP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方面的研究 已经证明了多价灭活轮状病毒疫苗抗原的可行性。与房车相关的新发现- C结构、自然获得性免疫和人类单抗的产生将帮助我们填补现有的 知识差距和开发适用于临床试验的轮状病毒-C疫苗方法。人们对此知之甚少 中和RV-C抗体应答的机制。绘制了RV-A和RV-B的中和表位图 到衣壳蛋白最突出的表面突起。有趣的是，第一个冷冻-EM原子结构 RV-C显示由VP1形成的独特的、突出的“指状”棘突，预测是显性免疫原性 表位。我们将在这些衣壳结构中测试特定类型和交叉反应的表位。最近的另一次 发现对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 假设感染RV-C可以诱导更强、更具交叉反应的中和抗体反应 与RV-A相比，持续时间更长，因为(I)它们有能力在幼儿中引发更严重的疾病， 以及(Ii)主要中和免疫原表位的一些关键结构和/或功能差异。为了测试 在这一假设下，我们提出了三个具体的目标：1)识别中和抗体的宿主和病毒决定因素 结合来自多个队列研究(n=14)的RV分型数据和滴度分析、时间 海岸儿童中这些抗体反应的出现和持续时间；2)确定RV-C 基因类型代表独特的血清型或共享共同的表位；3)使用人类单抗 与RV-C结合，绘制主要免疫原性表位图，确定RV-C抗体的作用机制 用低温EM进行中和和交叉中和。这些研究将为发展一种广泛的 保护性RV-C疫苗可能对感染RV-C风险增加的幼儿有显著好处 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.