Identifying functional antibody responses that protect against malaria in children

该项目旨在确定决定疟疾结果的抗体反应的目标和特征。 非洲幼儿感染。它使用系统血清学，结合多维抗体分析 用机器学习方法研究恶性疟原虫红细胞膜蛋白1(PfEMP1)的免疫应答。 疟疾感染红细胞(IES)表面的优势抗原。我们还研究关键的裂殖子抗原， 它们涉及对无症状寄生虫血症(AP)或无并发症疟疾(UM)的保护。 反应包括抗体亚类、亚型、Fc受体和补体结合，以及 抗体糖基化和亲和力。一些PfEMP1类型与脑型疟疾(CM)有关；其他类型可能 影响结果的范围包括AP、寄生虫清除和进展到UM。我们的 早期的工作验证了这种方法。我们将系统血清学应用于妊娠疟疾，并能够 确定对介导胎盘性疟疾的PfEMP1(VAR2CSA)的七个关键反应， 受保护的妇女容易感染胎盘疟疾的妇女。这七种方法中有四种是基于IE的检测方法。 这项拟议的研究设在马拉维的布兰太尔，这是一个国际疟疾研究卓越中心 (ICEMR)站点。在正在进行的研究中，患有CM的儿童进行视网膜检查和MRI扫描以评估神经血管 分别是累及和脑肿胀。具有UM的控件和具有AP的社区控件队列为 已登记并维持有效。在目标1中，我们使用Luminex技术治疗急性期和恢复期的血浆和寄生虫 分离株对广泛的PfEMP1蛋白片段的抗体反应特征 疟疾。从这些分析中，我们将确定儿童缺乏的对PfEMP1结构域的抗体反应 患有CM的儿童，无论有没有视网膜病变和脑肿胀，都会出现不同的症状， 康复期。 在目标2中，利用基于细胞的吞噬分析对目标1中确定的优先PfEMP1进行了深入研究， PfEMP1片段和表达相似PfEMP1类型的寄生虫株的呼吸爆发和激活。 为此，我们已经建立了单核细胞、中性粒细胞、NK细胞和全血的检测方法。 AIM 3利用马拉维ICEMR招募的社区队列，包括患有AP的儿童，研究如何 针对PfEMP1和裂殖子抗原的抗体影响AP的进化，以识别抗体反应 防止进展为UM或导致感染清除的药物。这些全面、综合的研究将 比较和对比预防CM、UM和明确寄生虫血症的抗体反应。 识别与生命保护相关的PfEMP1抗体的靶点和特性 威胁非洲儿童的疟疾将是开发定制疫苗或疗法的关键，以预防或 治疗严重的疟疾。发现疟疾感染谱中关键的保护性抗体反应将 揭示PfEMP1抗体和裂殖子对控制和消除疟疾的重要性。

This project aims to identify the targets and features of antibody responses that determine the outcome of malaria infection in young African children. It uses Systems Serology, combining multi-dimensional antibody profiling with machine learning, to study responses to Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), the dominant antigen on the surface of malaria infected erythrocytes (IEs). We also study key merozoite antigens, which are implicated in protection from asymptomatic parasitemia (AP) or uncomplicated malaria (UM). Responses include antibody subclass, isotype, and Fc receptor and complement engagement, together with antibody glycosylation and avidity. Some PfEMP1 types are implicated in cerebral malaria (CM); others may influence outcomes across a spectrum which includes AP, clearance of parasites and progression to UM. Our earlier work validates this approach. We applied Systems Serology to pregnancy malaria and were able to identify seven key responses to the PfEMP1 that mediates placental malaria (VAR2CSA), that distinguished women susceptible to placental malaria from protected women. Four of these seven were IE based assays. The proposed study is based in Blantyre, Malawi, an International Center of Excellence in Malaria Research (ICEMR) site. In ongoing studies, children with CM have retinal exams and MRI scans to assess neurovascular involvement and brain swelling, respectively. Cohorts of controls with UM and community controls with AP are enrolled and sustained. In Aim 1, we use Luminex technology on acute and convalescent plasma and parasite isolates to characterize antibody response to a broad range of PfEMP1 protein fragments implicated in severe malaria. From these analyses we will identify antibody responses to PfEMP1 domains that are lacking in children with CM, that differ between children with or without retinopathy and brain swelling, and that develop in convalescence from CM. In Aim 2, priority PfEMP1s identified in Aim 1 are studied in depth using cell-based assays of phagocytosis, respiratory burst and activation with both PfEMP1 fragments and parasite lines expressing similar PfEMP1 types. We have established assays using monocytes, neutrophils, NK cells and whole blood for this purpose. Aim 3 uses community cohorts recruited by the Malawi ICEMR, including children with AP, to study how antibodies to PfEMP1 and to merozoite antigens influence the evolution of AP, to identify antibody responses that prevent progression to UM or lead to clearance of infection. These comprehensive, integrated studies will compare and contrast antibody responses that protect against CM, against UM, and that clear parasitemia. Identifying the targets and properties of antibodies to PfEMP1 that are associated with protection from life threatening malaria in African children will be key to developing tailored vaccines or therapeutics to prevent or treat severe malaria. Discovering key protective antibody responses across the malaria infection spectrum will reveal the importance of antibody to PfEMP1 and merozoites for malaria control and elimination.