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

项目总结 抗体依赖增强(ADE)是一种抗体产生的现象 在随后的感染中，感染与类似的病原体发生交叉反应，导致病毒载量增加和 疾病的严重程度。寨卡病毒(ZIKV)感染由先前存在的DENV抗体引起的假说 在先天性ZIKV感染后观察到的严重不良妊娠结局中发挥作用。艾德是 通过病毒结合的免疫球蛋白抗体和宿主细胞上的Fc-受体(Fc-GMAR)之间的相互作用而介导。在……里面 人类，FCGR2Ars1801274的非同义单核苷酸多态(SNP)导致氨基 FcRIIA免疫球蛋白结合区第131位氨基酸由精氨酸(Arg131)变为组氨酸(His131)。上一首 体外研究表明，表达His131受体变体的细胞与人IgG1和IgG2结合 亲和力明显高于表达Arg131受体变异体的亲和力。我们假设每个人 高亲和力His131等位基因纯合子患病毒感染ADE的风险比个体更大 低亲和力Arg131等位基因纯合。在本应用程序中，我们将评估该SNP对ADE的影响 使用Arg131或His131等位基因纯合的K562细胞系和原代细胞株检测ZIKV 将按基因分层的人类单核细胞(目标1)。我们还生成了免疫球蛋白亚类开关 一种黄病毒反应性单抗的变种，我们将使用它来评估每一种免疫球蛋白亚类在 利用His131和Arg131纯合子K562细胞通过不同FcRia变异体介导ZIKV的ADE 从足月人胎盘分离的原代人类单核细胞和霍夫鲍尔细胞(目标2)。一个 全面了解影响ADE易感性的宿主遗传因素，包括所描述的因素 在这项建议中，可能有助于识别因以下原因而患严重疾病风险增加的人群 寨卡病毒感染，特别是在孕妇中。拟议的项目提供了一个极好的机会 培训包括传统病毒学和免疫学技术、专业发展和 将支持申请者成长为独立学术科学家的导师。

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.