Molecular Analysis of the PfEMP1 Binding Activity

由恶性疟原虫引起的疟疾是人类最重要的传染病之一。 据估计，每年有3亿-6.6亿次临床恶性疟疾发作，100万-200万次 死于感染。在恶性疟原虫中，var基因家族编码红细胞膜蛋白 (PfEMPI)，它们作为毒力因子，既导致抗原变异，又与受感染的 从红细胞到内皮。每个寄生虫基因组编码大约60个不同的PfEMPI蛋白 在寄生虫菌株之间，并结合不同的宿主受体。感染时会发生严重疟疾 红细胞滞留在大脑或胎盘中。这项拟议研究背后的具体假设是 特定的粘合剂类型可能由于其粘合取向而易患严重疟疾。这项研究将 确定PfEMPI蛋白的结合特性以及它们如何影响感染的红细胞对 不同的微血管内皮细胞。PfEMPI结合将从一种特征良好的寄生虫中进行研究 已适应在实验室中生长的分离物。表达特定PfEMPI变异体的寄生虫系 将通过有限稀释克隆或在不同宿主受体上进行选择而产生。实时荧光聚合酶链式反应 使用针对var基因家族的基因特异性引物的方法将被用于定义var基因。 在不同的行中表达。将确定每个PfEMPI蛋白的特定黏附特性 通过表征受感染的红细胞与广泛的宿主受体和 微血管内皮细胞。这些研究将有助于详细描述 寄生虫的细胞黏附特性，使人们能够更好地了解疟疾的分子基础 发病机制。

Malaria caused by Plasmodium falciparum is one of the most important infectious diseases of humankind. Each year there is an estimated 300-660 million episodes of clinical P. falciparum malaria and 1-2 million will die from the infection. In P. falciparum, the family of var genes encode erythrocyte membrane proteins (PfEMPI), which act as virulence factors responsible for both antigenic variation and binding of infected erythrocytes to endothelium. Each parasite genome encodes approximately 60 PfEMPI proteins that differ between parasite strains and bind different host receptors. Severe malaria occurs when infected erythrocytes sequester in brain or placenta. The specific hypothesis behind the proposed research is that particular adhesive types may predispose to severe malaria because of their binding tropism. This study will determine the binding properties of PfEMPI proteins and how they affect infected erythrocyte selectivity for different microvascular endothelial cells. PfEMPI binding will be studied from a well characterized parasite isolate that has been adapted to grow in the laboratory. Parasite lines expressing specific PfEMPI variants will be generated by limited dilution cloning or by selection on different host receptors. Real-time PCR approaches with gene-specific primers to the family of var genes will be used to define the var genes expressed in the various lines. The specific adhesion properties of each PfEMPI protein will be determined by characterizing infected erythrocyte adhesion against an extensive panel of host receptors and microvascular endothelial cells. These studies will contribute to a detailed characterization of the cytoadhesive properties of a parasite and enable a greater understanding of the molecular basis of malaria pathogenesis.