Antigen Discovery and Vaccine Development for Human Babesia Parasites

人类巴贝虫寄生虫的抗原发现和疫苗开发

基本信息

批准号：
10386919
负责人：
CHOUKRI BEN MAMOUN
金额：
$ 41.88万
依托单位：
YALE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-05-13 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10386919
关键词：
Adjuvant Antibodies Antigens Babesia Babesia microti Babesiosis Biological Biology Black-legged Tick Blood Blood Transfusion Borrelia microti California Case Fatality Rates Case Study Cell membrane Cells Cellular biology Centers for Disease Control and Prevention (U.S.)Clinical Combined Modality Therapy Cytoplasm Dermacentor Disease Dose Environment Erythrocyte Membrane Erythrocytes Future Genomics Goals Human Immune response Immunization Immunobiology Immunocompetent Immunodominant Antigens Immunoglobulin G Immunoglobulin M Incidence Individual Infection Kinetics Life Cycle Stages Link Malaria Measures Membrane Molecular Mus Oregon Orthologous Gene Parasites Pathogenesis Pathologic Pharmaceutical Preparations Plasmodium falciparum Predisposition Protein Export Pathway Protein Secretion Proteins Proteome Proteomics Recombinants Reporting Research Serology Spleen Surface System Techniques Ticks United States Vaccines Virulence Virulence Factors Washington associated symptom base detection assay diagnostic assay immunogenicity in silico macrophage mouse model nano protective efficacy response side effect success tick-borne transcriptomics vaccine access vaccine development vaccine efficacy vaccine trial

项目摘要

Human babesiosis is a tick-borne malaria-like illness with a worldwide distribution and endemic in the United States. The disease joined the list of CDC-nationally notifiable diseases in 2011 due to the increasing number of reported cases. The majority of clinical cases in the US have been linked to Babesia microti whereas Babesia duncani cases have been reported primarily from Washington, Oregon, and California. However, due to the lack of specific diagnostic assays and because immune competent individuals can be asymptomatic, the true incidence of babesiosis cases in the US and worldwide is most likely underestimated. There is no vaccine against human babesiosis and current therapies are not effective, require high doses and some of them are associated with major side effects. Even with these drugs and other supportive measures, the case fatality rate exceeds 20% in susceptible hosts. During the past 8 years, we gained significant understanding of the biology, pathogenesis and drug susceptibility of Babesia parasites that infect humans: (1) we completed the first genomic and transcriptomic analyses and annotations of B. microti and B. duncani; (2) probed the genomic diversity of B. microti in human blood and ticks; (3) demonstrated that B. microti and B. duncani are inherently tolerant to clinically recommended therapies; (4) discovered a combination therapy that results in radical cure of B. microti infection in mice; (5) completed the first immunoproteomic analysis of B. microti, identified the main immunodominant antigens of this parasite, and developed the first diagnostic assay for detection of active B. microti infection; and (6) discovered a vesicular-based secretion system used by the parasite to export some of its proteins to the host. Of particular relevance to the current RFA, we used immunoproteomic and proteomic approaches to identify secreted and surface-displayed proteins of B. microti and B. duncani, and for more than 30 B. microti antigens determine their serological profile in sera from infected mice and humans. The main hypothesis of this proposal is that some of the exported antigens of B. microti and B. duncani could serve as vaccines to illicit antibodies to block Babesia invasion of host erythrocytes or to facilitate elimination of Babesia- infected erythrocytes by host macrophages. The primary goals of this application are to further characterize the immunogenicity profile of these secreted antigens, and to conduct vaccination studies in mice to identify those antigens that could be developed as vaccines against Babesia microti and B. duncani infections. In Aim 1, we will produce functional recombinant forms of secreted and surface displayed proteins of B. microti and B. duncani and use them to determine the serological profile and kinetics of the humoral immune responses using mouse and human sera. In Aim 2. We will conduct cell biological studies to determine the secretion and cellular distribution of the candidate exported antigens during the intraerythrocytic life cycle of these parasites. In Aim 3, we will conduct immunization studies in mouse models of B. microti and B. duncani infections to identify those antigens that are effective vaccines when administered in human-compatible adjuvants.

人类巴贝斯虫病是一种蜱传疟疾样疾病，在世界范围内分布，在美国流行国家。由于病例数量不断增加，该病于 2011 年被列入 CDC 国家法定传染病清单。报告的病例。美国的大多数临床病例与田鼠巴贝虫有关，而巴贝虫邓卡尼病例主要报告于华盛顿州、俄勒冈州和加利福尼亚州。然而，由于缺乏特定诊断测定的结果，并且由于具有免疫能力的个体可能无症状，因此真正的美国和全世界巴贝虫病病例的发病率很可能被低估。没有疫苗可以预防人类巴贝斯虫病和目前的治疗方法无效，需要高剂量，其中一些是相关的有重大副作用。即使使用这些药物和其他支持措施，病死率仍超过易感宿主中为20%。在过去的8年里，我们对生物学有了深入的了解，感染人类的巴贝虫寄生虫的发病机制和药物敏感性：（1）我们完成了第一个基因组研究以及 B. microti 和 B. ducani 的转录组分析和注释； (2)探讨了B.的基因组多样性。人类血液和蜱虫中的田鼠； (3) 证明 B. microti 和 B. ducani 具有固有的耐受性临床推荐的疗法； (4) 发现了一种可以根治田鼠芽孢杆菌的联合疗法小鼠感染； (5)完成了首次B. microti的免疫蛋白质组分析，鉴定了主要这种寄生虫的免疫显性抗原，并开发了第一个用于检测活性 B. 田鼠感染； (6) 发现了寄生虫使用的基于囊泡的分泌系统来输出一些它的蛋白质给宿主。与当前的 RFA 特别相关的是，我们使用了免疫蛋白质组学和蛋白质组学识别 B. microti 和 B. ducani 的分泌蛋白和表面展示蛋白的方法，并且超过 30 田鼠 B. 抗原决定了受感染小鼠和人类血清中的血清学特征。主要该提案的假设是，田鼠芽孢杆菌和邓氏芽孢杆菌的一些输出抗原可以作为非法抗体疫苗可阻止巴贝虫侵入宿主红细胞或促进消除巴贝虫宿主巨噬细胞感染红细胞。该应用的主要目标是进一步表征这些分泌抗原的免疫原性特征，并在小鼠中进行疫苗接种研究以鉴定这些抗原可开发为针对田鼠巴贝虫和邓肯巴贝虫感染的疫苗的抗原。在目标 1 中，我们将产生 B. microti 和 B. ducani 的分泌蛋白和表面展示蛋白的功能重组形式并用它们来确定小鼠体液免疫反应的血清学特征和动力学和人类血清。在目标 2 中，我们将进行细胞生物学研究，以确定分泌和细胞在这些寄生虫的红细胞内生命周期中候选输出抗原的分布。在目标 3 中，我们将在田鼠芽孢杆菌和邓氏芽孢杆菌感染的小鼠模型中进行免疫研究，以识别这些感染当与人类相容的佐剂一起施用时，抗原是有效的疫苗。