Babesiosis: An Emerging Infectious Threat to Transfusion Medicine

描述（由申请方提供）：巴贝虫病是一种人畜共患病，是一种可从动物传染给人的疾病。啮齿类寄生虫小巴贝虫和牛病原体分歧巴贝虫是迄今为止全球报告的大多数人类感染的原因。从血液安全的角度来看，涉及巴氏杆菌属的输血传播感染。在美国已经变得越来越成问题，每年报道的越来越多。因此，对这种血液传播的寄生虫的研究应被视为输血医学的优先事项。我们的目的是了解B的入侵过程。该研究的最终目的是利用在入侵中发挥关键作用的寄生虫分子作为诊断和血液筛查工具。本研究建立了体外研究B对人红细胞侵袭的实验系统。分歧者，允许使用B的活裂殖子直接探索与寄生虫侵入人RBC相关的事件。分歧者寄生虫表面的分子和顶端细胞器分泌的分子在宿主/寄生虫界面起作用，如果我们要定义入侵机制的步骤并确定新的治疗靶点，我们需要识别它们并确定它们的相互作用和功能。我们已经确定了这样一个假定的红细胞结合配体，Bd 30和我们的项目的重点是研究其相互作用的红细胞，特别是血型糖蛋白，在寄生虫入侵。本研究的目的有三：（1）鉴定血型糖蛋白A（GPA）和血型糖蛋白B（GPB）作为B的红细胞受体。（2）证实Bd 30为趋异侵袭的B。（3）探讨结合血型糖蛋白A（GPA）和/或血型糖蛋白B（GPB）的趋异配体与Bd 30的相互作用在裂殖子侵袭中的功能意义。所提出的方法包括使用RBC的特定酶处理的侵袭测定抑制、缺乏确定的RBC抗原的突变细胞以及使用抗体和竞争肽;在侵袭测定中使用天然和重组Bd 30配体蛋白和针对Bd 30的抗体的红细胞结合测定，以及提出的基因缺失以研究其功能。因此，该项目的主要目标是阐明参与B进入的分子机制。使裂殖子进入红细胞。预计本提案中详述的研究将产生用于诊断、流行病学和治疗及预防人类巴贝虫病的试剂，并有助于开发用于筛查血液制品的产品。

DESCRIPTION (provided by applicant): Babesiosis is a zoonosis, a disease communicable from animals to man. The rodent parasite, Babesia microti and the bovine pathogen, Babesia divergens are responsible for most of the human infections that have been reported to date, globally. From a blood safety perspective, transfusion-transmitted infections involving Babesia spp. have become increasingly problematic in the USA, with progressively more reported each year. Therefore the study of this blood-borne parasite should be considered as a priority for transfusion medicine. Our purpose is to understand the invasion process of B. divergens into the human red blood cell (RBC), with the ultimate aim of exploiting parasite molecules found to play key roles in invasion as diagnostic and blood screening tools. The in-vitro system that we use for studying invasion of the human red cell by B. divergens, permits direct exploration of the events associated with parasite invasion of the human RBC, using viable merozoites of B. divergens. Molecules on the surface of the parasite and those secreted by apical organelles function at the host/parasite interface, and we need to identify them and determine their interactions and function, if we are to define the steps in the invasion mechanism and identify new therapeutic targets. We have identified one such putative RBC binding ligand, Bd30 and the focus of our project is the study of its interaction with the RBC, specifically the glycophorins, during parasite invasion. There are three specific aims in this proposal (1) To characterize glycophorin A (GPA) and glycophorin B (GPB) as RBC receptors for B. divergens invasion (2) To validate Bd30 as the B. divergens ligand that binds glycophorin A (GPA) and/or glycophorin B (GPB) and to characterize Bd30 in the parasite and (3) To evaluate the functional significance of the interaction between GPA and/or GPB and Bd17 in merozoite invasion. Methodology that is proposed includes inhibition of invasion assays using specific enzyme treatments of the RBC, mutant cells lacking defined RBC antigens and the use of antibodies and competitor peptides; erythrocyte binding assays using native and recombinant Bd30 ligand protein and antibodies against Bd30 in invasion assays, as well as proposed gene deletion to study its function. Thus, the major goal of the project is to elucidate the molecular mechanisms involved in the entry of B. divergens merozoites into the erythrocyte. It is anticipated that studies detailed in this proposal will result in reagents for diagnosis, epidemiology and treatment and prevention of human babesiosis, and assist in developing products to screen blood products.