Babesiosis: An Emerging Infectious Threat to Transfusion Medicine

巴贝斯虫病：对输血医学的新的感染威胁

• 批准号: 8022336
• 负责人: Cheryl Ann Lobo
• 金额: $ 40.6万
• 依托单位: NEW YORK BLOOD CENTER
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8022336
• 关键词: Affinity; Animals; Antibodies; Antigens; Apical; Appearance; Babesia; Babesia microti; Babesiosis; Binding; Biological Assay; Blood; Blood Screening; Blood Transfusion; Blood donor screening; Carbohydrates; Cattle; Cell physiology; Cells; Communicable Diseases; Confocal Microscopy; DNA; Development; Diagnosis; Diagnostic; Enzymes; Epidemiology; Erythrocytes; Event; Gel; Gene Deletion; Genes; Glycophorin; Glycophorin A; Glycophorin B; Glycoside Hydrolases; Goals; Human; Immunofluorescence Immunologic; Immunoglobulin Fragments; Immunoprecipitation; In Vitro; Infection; Intervention; Knowledge; Ligand Binding; Ligands; Malaria; Medicine; Membrane Proteins; Methodology; Methods; Microscopic; Molecular; New York; Organelles; Parasites; Parasitic infection; Pattern; Peptide antibodies; Peptides; Physiologic pulse; Play; Prevention; Process; Proteins; Reagent; Recombinant Proteins; Recombinants; Reporting; Rodent; Role; Safety; Screening procedure; Surface; System; Testing; Tight Junctions; Transfection; Transfusion; Western Blotting; Zoonoses; blood product; cDNA Library; experience; extracellular; in vitro Assay; interest; man; mutant; neglect; new therapeutic target; novel; parasite invasion; pathogen; receptor; sugar; tool; transmission process

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. PUBLIC HEALTH RELEVANCE: Babesiosis is a zoonosis, a disease communicable from animals to man and an important blood-borne human parasitic infection. Human to human transmission of the parasite is well recognized to occur through blood transfusion. Despite being a significant threat to the safety of blood transfusions, its study has largely been neglected. The long term objective of the present proposal is to develop a detailed mechanistic understanding of the erythrocytic invasion of the B. divergens parasite in order to develop novel therapies for treating the infection and effective strategies for screening of blood donors for babesia infection. We are specifically looking at interactions between the RBC receptors, glycophorins A and B and the Babesia molecules that bind to them so that we can define the steps in the invasion mechanism. Recognizing that Babesia is an expanding blood safety threat we are interested in the development of viable interventions to detect and halt transmission of these pathogens via blood transfusions.

描述（由申请人提供）：巴贝虫病是一种人畜共患疾病，是一种从动物传染给人类的疾病。迄今为止，全球报告的大多数人类感染都是由啮齿类寄生虫田鼠巴贝斯虫和牛病原体分歧巴贝斯虫引起的。从血液安全的角度来看，涉及巴贝虫属的输血传播感染。在美国，这一问题变得越来越严重，每年报告的数量都在增加。因此，对这种血源性寄生虫的研究应被视为输血医学的优先事项。我们的目的是了解分歧芽孢杆菌侵入人类红细胞（RBC）的过程，最终目的是利用在侵入中发挥关键作用的寄生虫分子作为诊断和血液筛查工具。我们用于研究分歧芽孢杆菌侵入人类红细胞的体外系统，允许使用分歧芽孢杆菌的活裂殖子直接探索与寄生虫侵入人类红细胞相关的事件。寄生虫表面的分子和顶端细胞器分泌的分子在宿主/寄生虫界面发挥作用，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。我们已经确定了一种假定的红细胞结合配体 Bd30，我们项目的重点是研究寄生虫入侵过程中其与红细胞（特别是糖蛋白）的相互作用。该提案有三个具体目标 (1) 表征血型糖蛋白 A (GPA) 和血型糖蛋白 B (GPB) 作为 B. divergens 入侵的 RBC 受体 (2) 验证 Bd30 作为结合血型糖蛋白 A (GPA) 的 B. divergens 配体) 和/或血型糖蛋白 B (GPB) 并表征寄生虫中的 Bd30，以及 (3) 评估 GPA 之间相互作用的功能意义和/或裂殖子入侵中的 GPB 和 Bd17。提出的方法包括使用红细胞的特定酶处理、缺乏确定的红细胞抗原的突变细胞以及使用抗体和竞争肽来抑制入侵测定；在侵袭测定中使用天然和重组 Bd30 配体蛋白和抗 Bd30 抗体进行红细胞结合测定，以及提议的基因删除以研究其功能。因此，该项目的主要目标是阐明分歧芽孢杆菌裂殖子进入红细胞的分子机制。预计该提案中详细的研究将产生用于人类巴贝斯虫病的诊断、流行病学以及治疗和预防的试剂，并协助开发用于筛选血液制品的产品。 公共卫生相关性：巴贝虫病是一种人畜共患疾病，是一种从动物传染给人类的疾病，也是一种重要的血源性人类寄生虫感染。众所周知，寄生虫的人际传播是通过输血发生的。尽管对输血安全构成重大威胁，但其研究在很大程度上被忽视。本提案的长期目标是对发散芽孢杆菌寄生虫红细胞侵袭形成详细的机制了解，以便开发治疗感染的新疗法以及筛选献血者巴贝虫感染的有效策略。我们专门研究红细胞受体、血型糖蛋白 A 和 B 以及与其结合的巴贝虫分子之间的相互作用，以便我们能够定义入侵机制的步骤。认识到巴贝虫病是一种不断扩大的血液安全威胁，我们有兴趣开发可行的干预措施来检测和阻止这些病原体通过输血的传播。