Functional assays of Plasmodium vivax DBP, EBP, and RBP2b in erythrocyte invasion in Duffy-Negative Africans

项目摘要 间日疟原虫红细胞入侵机制与体液免疫 达菲阴性非洲人的反应 非洲血统的人被认为受到保护，免受间日疟原虫的侵袭 感染是因为他们的红细胞表面缺乏Duffy抗原的表达 使间日疟原虫不能入侵它们的红细胞。然而，越来越多的人 非洲各地报告的间日疟病例和达菲阴性患者对此提出了挑战 传统的教条，增加了间日疟原虫的一些谱系可能有 进化到使用Duffy结合蛋白以外的配体来侵袭红细胞。这个 Duffy阴性个体对P. 间日疟原虫感染在很大程度上是未知的。在此应用程序中，我们将调查 达菲阴性间日疟原虫红细胞结合基因的表达及功能 达菲阴性个体对间日疟原虫侵袭的抗体应答 蛋白质。有三个具体的目标：1)识别差异表达的基因 间日疟原虫达菲阳性与阴性间日疟原虫的RNA-SEQ比较；2)体外检测 间日疟原虫配基蛋白Aim 1与Duffy-1结合和侵袭活性的研究 红细胞阴性；以及3)检测靶向间日疟原虫的体内抗体水平 Duffy阴性患者与红细胞侵袭相关的抗原。作为我们的研究 埃塞俄比亚的一些地点有大量间日疟病例，占相当大的比例。 对于达菲阴性的人，我们有一个独特的机会来研究入侵 间日疟原虫在非洲的传播机制，并填补关键的知识空白 现象时有发生。我们已建立的实验室培养设施靠近健康中心 从培养的裂殖体中获得的成功的间日疟原虫转录组数据 论证了拟议研究的可行性。间日疟原虫的比较 达菲阴性和达菲阳性个体之间的转录本将提供第一个 间日疟原虫允许感染达菲的遗传和功能属性的描述 红细胞为阴性。这些数据将对开发分子标记具有价值 鉴定能够感染达菲阴性个体的间日疟原虫菌株。这样的标记将 能够对这一现象进行大范围的筛查和表征，并可能从根本上 改变我们对非洲间日疟原虫流行病学的理解。此外，对 间日疟原虫关键配体蛋白(S)用于Duffy阴性红细胞的侵袭和宿主 免疫应答对间日疟原虫疫苗的研制具有重要意义。

Project Summary Title: Plasmodium vivax Erythrocyte Invasion Mechanisms and Humoral Immune Response in Duffy Negative Africans Individuals of African ancestry are thought to be protected from Plasmodium vivax infection because they lack Duffy antigen expression on the surface of their erythrocytes rendering P. vivax unable to invade their red blood cells. However, an increasing number of P. vivax cases reported across Africa and in Duffy-negative individuals challenges this conventional dogma, raising the possibility that that some lineages of P. vivax may have evolved to use ligands other than Duffy Binding Protein for erythrocyte invasion. The intrinsic invasion mechanism and immune response of Duffy-negative individuals to P. vivax infections are largely unknown. In this application, we will investigate the expression and function of erythrocyte binding genes in Duffy-negative P. vivax and the antibody response of Duffy-negative individuals to P. vivax invasion proteins. There are three specific aims: 1) to identify genes with differential expression between Duffy-positive and Duffy-negative P. vivax by RNA-seq; 2) to determine in vitro binding and invasion activities of P. vivax ligand proteins identified from Aim 1 to Duffy- negative red blood cells; and 3) to examine in vivo antibody levels to targeted P. vivax antigens associated with erythrocyte invasion in Duffy-negative patients. As our study sites in Ethiopia have a large number of P. vivax cases and a significant proportion of Duffy-negative individuals, we have a unique opportunity to study the invasion mechanisms of P. vivax in Africa and fill critical knowledge gaps in how this phenomenon occurs. Our established lab culture facility close to the health centers and successful P. vivax transcriptome data obtained from cultured schizonts have demonstrated the feasibility of the proposed research. Comparison of P. vivax transcriptomes between Duffy-negative and Duffy-positive individuals will provide the first description of the genetic and functional attributes of P. vivax that permit infection of Duffy- negative erythrocytes. These data will be valuable to develop molecular markers that identify P. vivax strains able to infect Duffy-negative individuals. Such markers would enable wide-scale screening and characterization of this phenomenon and could radically change our understanding of P. vivax epidemiology in Africa. Further, the identification of key ligand protein(s) P. vivax uses for Duffy-negative erythrocyte invasion and host immune response will have important implications for P. vivax vaccine development.