Defining targets of protective immunity in Plasmodium vivax using human monoclonal antibodies

间日疟原虫（Plasmodium vivax，Pv）是世界范围内疟疾的主要病因， 义务军人。它也是退伍军人患疟疾的一个重要原因，因为寄生虫会产生一种 潜伏期感染，可能在数年后复发。我们的目标是开发一种疫苗和新的疗法 对于PV。疫苗开发工作的目标是一种多组分疫苗，其靶向多个阶段的 PV在人体内的生命周期在这个建议中，我们的重点是两个必要的Pv蛋白所需的寄生 红细胞（在这种情况下是网织红细胞）的入侵。这些是达菲结合蛋白（DBP）和 网织红细胞结合蛋白2b（RBP 2b）。我们的方法是产生人单克隆抗体（mAb） 来自对PV具有天然获得性免疫的个体。使用来自具有强大免疫力的供体的B细胞 反应，我们将鉴定特异性针对DBP和RBP 2 B的B细胞，并产生针对这两种必需的mAb。 入侵蛋白我们将测试单克隆抗体是否可以阻断Pv蛋白与其受体的结合， 网织红细胞，如果是这样，他们是否可以在体外抑制Pv入侵的网织红细胞。然后我们将决定 哪些Pv蛋白靶（表位）被最有效的mAb识别。我们将确定mAb靶点 其可能在全球范围内存在于Pv毒株中，因此可用于包含在泛全球疫苗中。的 然后将测试最有希望的mAb在Aotus中保护免受Pv血液阶段感染的能力。 Pv感染的猴模型。与我们在秘鲁NAMRU-6灵长类动物单位的合作者合作， 被动地转移给非洲长尾猴，并监测动物对Pv疟疾的保护。 在动物保护实验取得结果之前，我们将继续进一步发展一种 候选疫苗（一种免疫原），包含已鉴定的Pv基本靶点。我们会用一本小说 这是一种基于动物的方法，以产生稳定的免疫原，称为纳米抗体或VHH抗体。我们的研究 将涉及由在退伍军人医院从事疟疾研究的经验丰富的科学家精心策划的合作， 美国俄亥俄州克利夫兰市医学事务中心;凯斯西储全球健康与疾病中心 俄亥俄州克利夫兰大学;柬埔寨巴斯德研究所疟疾股;沃尔特和伊丽莎霍尔研究所， 澳大利亚;以及秘鲁的NAMRU-6部队。我们的研究结果将使多组分疫苗的进展成为可能。 反对PV。他们还将推进抗体治疗重症患者和 在季节性传播和图尔斯执勤期间需要持续预防。 !

Plasmodium vivax (Pv) is a major cause of malaria worldwide and frequently results in illness among active duty military personnel. It is also an important cause of malaria in veterans because the parasite develops a latent stage of infection that can relapse years later. Our aim is to develop a vaccine and novel therapeutics for Pv. The goal for vaccine development efforts is a multi-component vaccine that targets multiple stages of the Pv life cycle in humans. In this proposal, our focus is on two essential Pv proteins required for parasitic invasion of red blood cells (in this case, reticulocytes). These are the Duffy Binding Protein (DBP) and the Reticulocyte Binding Protein 2b (RBP2b). Our approach is to generate human monoclonal antibodies (mAbs) from individuals with naturally-acquired immunity to Pv. Using B cells from donors with robust immune responses, we will identify B cells specific for DBP and RBP2b and generate mAbs against these two essential invasion proteins. We will test whether the mAbs can block the binding of Pv proteins to their receptors on reticulocytes and if so, whether they can inhibit Pv invasion of reticulocytes in vitro. We will then determine which Pv protein targets (epitopes) are recognized by the most effective mAbs. We will identify the mAb targets that are likely to be present in Pv strains globally and thus useful for inclusion in a pan-global vaccine. The most promising mAbs will then be tested for their ability to protect against Pv blood stage infection in an Aotus monkey model of Pv infection. Working with our collaborators at the NAMRU-6 primate unit in Peru, mAbs will be passively transferred to Aotus monkeys and the animals monitored for protection against Pv malaria. Pending the outcome of our animal protection experiments, we will proceed with further development of a vaccine candidate (an immunogen) that incorporates the essential Pv targets identified. We will use a novel animal-based approach to generate stable immunogens known as nanobodies or VHH antibodies. Our studies will involve a carefully orchestrated collaboration by experienced scientists working on malaria at the Veterans Affairs Medical Center in Cleveland, OH; Center for Global Health and Diseases at Case Western Reserve University in Cleveland, OH; Malaria Unit, Institute Pasteur, Cambodia; Walter and Eliza Hall Institute, Australia; and the NAMRU-6 unit in Peru. Our results will enable progress toward a multi-component vaccine against Pv. They will also advance the potential of antibody therapies for severely ill individuals and those in need of sustained prophylaxis during seasonal transmission and tours of duty. !