Effect of an Fc Gamma Receptor Polymorphism on Antibody-Dependent Enhancement of Zika Virus Infection

项目摘要 抗体依赖性增强（ADE）是一种现象，通过这种现象，抗体响应于主要的免疫应答而产生。 感染在随后的感染中与类似的病原体发生交叉反应，导致病毒载量增加， 疾病的严重性。已假设寨卡病毒（ZIKV）感染由既存DENV抗体引起的ADE 在先天性ZIKV感染后观察到的严重不良妊娠结果中发挥作用。艾德是 通过病毒结合的IgG抗体和宿主细胞上的Fc γ受体（Fc γ R）之间的相互作用介导。在 在人类中，FCGR2A，rs1801274中的非同义单核苷酸多态性（SNP）导致氨基酸缺失。 在Fc区RIIA的IgG结合区中，位点131处的酸从精氨酸（Arg131）变为组氨酸（His131）。先前 体外研究表明，表达His 131受体变体的细胞与人IgG 1和IgG 2结合， 与表达Arg131受体变体的那些相比，具有显著更高的亲和力。我们假设个体 高亲和力His131等位基因纯合子的患者发生病毒感染ADE的风险高于个体 低亲和力Arg131等位基因纯合。在本申请中，我们将评估该SNP对ADE的影响。 使用衍生自K562细胞的细胞系，所述细胞系对于Arg131或His131等位基因是纯合的，并且主要 将通过基因型分层的人单核细胞（目的1）。我们还产生了IgG亚类开关 我们将使用黄病毒反应性单克隆抗体的变体来评估每个IgG亚类在 使用His131和Arg131纯合K562细胞通过不同的Fc ε RIIA变体介导ZIKV的ADE 细胞系、原代人单核细胞和从足月人胎盘分离的Hofbauer细胞（目的2）。一 全面了解影响ADE易感性的宿主遗传因素，包括描述的因素 在这项建议中，可能有助于确定由于以下原因而增加患严重疾病风险的人群： ZIKV感染，尤其是孕妇。拟议项目提供了一个极好的机会， 包含传统病毒学和免疫学技术的培训，专业发展，以及 导师，这将支持申请人的成长为一个独立的学术科学家。

PROJECT SUMMARY Antibody-dependent enhancement (ADE) is a phenomenon by which antibodies raised in response to a primary infection cross-react to a similar pathogen during a subsequent infection, resulting in increased viral load and severity of disease. ADE of Zika virus (ZIKV) infection by preexisting DENV antibodies has been hypothesized to play a role in the severe adverse pregnancy outcomes observed following congenital ZIKV infection. ADE is mediated by interactions between virus-bound IgG antibodies and Fc gamma receptors (FcRs) on host cells. In humans, a nonsynonymous single nucleotide polymorphism (SNP) in FCGR2A, rs1801274, results in an amino acid change at site 131 from arginine (Arg131) to histidine (His131) in the IgG-binding region of FcRIIA. Previous work in vitro has shown that cells expressing the His131 receptor variant bind human IgG1 and IgG2 with significantly higher affinity than those expressing the Arg131 receptor variant. We hypothesize that individuals homozygous for the high affinity His131 allele will be at greater risk for ADE of viral infection than individuals homozygous for the low affinity Arg131 allele. In this application, we will assess the effect of this SNP on ADE of ZIKV using cell lines derived from K562 cells that are homozygous for the Arg131 or His131 allele and primary human monocytes that will be stratified by genotype (Aim 1). We have also generated IgG subclass switch variants of a flavivirus-reactive monoclonal antibody that we will use to assess the role of each IgG subclass in mediating ADE of ZIKV through the different FcRIIA variants using His131 and Arg131 homozygous K562 cell lines, primary human monocytes, and Hofbauer cells isolated from full term human placentas (Aim 2). A comprehensive understanding of host genetic factors that affect susceptibility to ADE, including those described in this proposal, may help to identify populations at increased risk of developing severe disease as a result of ZIKV infection, particularly among pregnant women. The proposed project provides an excellent opportunity for training that encapsulates traditional virology and immunology techniques, professional development, and mentorship that will support the applicant’s growth as an independent academic scientist.