Point-of-care diagnostic test for T. cruzi (Chagas) infection

克氏锥虫（恰加斯）感染的即时诊断测试

• 批准号: 9757680
• 负责人: Andrew E. Levin
• 金额: $ 29.93万
• 依托单位: KEPHERA DIAGNOSTICS, LLC
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-07 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9757680
• 关键词: Acute; Address; Algorithms; Antigen-Antibody Complex; Antigenic Diversity; Antigenic Variation; Antigens; Area; Bedside Testings; Biological Assay; Blood; Blood Screening; Blood Transfusion; Blood specimen; Blood-Borne Pathogens; Bolivia; Bolivian; CD69 antigen; Cardiomyopathies; Caring; Chagas Cardiomyopathy; Chagas Disease; Chromatography; Clinical; Clinical Research; Clinical Sensitivity; Crude Extracts; Data; Detection; Development; Devices; Diagnosis; Diagnostic; Diagnostic tests; Disease; Enzyme-Linked Immunosorbent Assay; Epidemiologic Monitoring; Etiology; Exhibits; Family; Filtration; Fingers; Generations; Genotype; Geography; Goals; Gold; HIV; HIV diagnosis; Hepatitis C virus; Human; Immigrant; Immune Evasion; Individual; Infection; Infrastructure; Insect Vectors; International; Ion Exchange; Laboratories; Laboratory Diagnosis; Lateral; Latex Bead; Latin America; Leishmania; Mass Spectrum Analysis; Measures; Medical; Megacolon; Megaesophagus; Methods; Molecular; Morbidity - disease rate; Organ Transplantation; Outcome; Parasites; Parasitic Diseases; Parasitic infection; Pathologic; Patients; Performance; Phase; Planets; Plasma; Population; Preparation; Prevalence; Procedures; Proteins; Public Health; Publishing; Reader; Recombinants; Resources; Risk; Sampling; Sensitivity and Specificity; Serologic tests; Serum; Specificity; System; Test Result; Testing; Transfusion; Trypanosoma; Trypanosoma cruzi; Underserved Population; Universities; Vascular blood supply; Vero Cells; Western Blotting; Whole Blood; Wireless Technology; World Health Organization; assay development; base; chronic infection; clinical Diagnosis; cost; cost effective; cross reactivity; experience; falls; gel electrophoresis; in vitro testing; innovation; meetings; mortality; point of care; point-of-care diagnostics; portability; preclinical study; prevent; prototype; research clinical testing; rural area; tool; transmission process; vector-borne; virtual laboratory

Project Summary Chagas disease, caused by infection with the parasite Trypanosoma cruzi, is the most prevalent parasitic disease in the western hemisphere, infecting 8-11 million individuals and with over 70 million at risk. The infection is transmitted by an insect vector, but can also be acquired through blood transfusion, organ transplant, or congenitally. Following a brief acute phase, the parasite persists for years in infected carriers, often asymptomatically, but can cause cardiomyopathy and other pathological conditions leading to severe morbidity and mortality. In the U.S., the prevalence of T. cruzi infection measured in immigrant populations has led to the implementation of blood screening assays to prevent transfusion transmission. The gradual encroachment of the insect vector into the southernmost regions of the U.S. has also raised the threat of autochthonous transmission. Chagas disease is challenging to diagnose due to the combination of genotypic and hence antigenic variation across its geographical range, complex immunological interactions with the human host, and cross-reactivities with other parasites. Serology has become the mainstay for diagnosis, especially for chronic infection, but the above challenges have hampered the accuracy of serologic tests such that multiple assays are commonly used in a triangulation algorithm to establish final results. The majority of those at risk for T. cruzi infection live in low-resource, underdeveloped areas where contact with the vector insects is hard to avoid, but medical care is relatively primitive and laboratory infrastructure is absent. For these reasons, rapid, point-of-care tests have become increasingly desirable as tools for diagnosis and epidemiological surveillance of Chagas disease. The current generation of Chagas rapid tests is limited by suboptimal performance, both with respect to sensitivity and specificity, however, largely due to the reliance on recombinant antigens which are specific to certain T. cruzi strains or lineages or stages of infection. To date, only one Chagas rapid test has been cleared by FDA. In this project, we propose to develop a rapid test for Chagas disease, based on a semi-purified native protein preparation from cultured T. cruzi termed TESA (Trypanosomal Excreted/Secreted Antigens). In preliminary studies by applicants and others, TESA immunoblots have shown clinical sensitivity and specificity approaching 100% across a range of genotypes and lineages. We have developed a purification procedure to enrich and concentrate the antigenic component of TESA, making it suitable for use in a lateral flow assay format. We have used this antigen in a prototype simplified lateral flow assay, which exhibited greater analytical sensitivity than the FDA-cleared rapid test and broad detection of T. cruzi infections across Latin America. In Phase I, we will develop a complete, TESA- based lateral flow rapid test suitable for point-of-care use in low-resource settings. TESA lateral flow test results will be read using a field-friendly, ultraportable, low-cost reader that will provide objective interpretation and enable wireless upload of data to local devices or remote servers. Phase II will support complete development to commercial stage, clinical evaluation and FDA submission of the TESA lateral flow test for in vitro diagnosis of Chagas disease.

项目摘要 恰加斯病是最流行的寄生虫，由克氏锥虫感染引起。 这种疾病在西半球蔓延，感染800万至1100万人，有7000多万人处于危险之中。这个 感染是通过昆虫媒介传播的，但也可以通过输血、器官感染 移植，或先天的。在短暂的急性期之后，寄生虫在受感染的携带者体内持续多年， 通常无症状，但可引起心肌病等病理情况，导致严重 发病率和死亡率。在美国，在移民人口中测量的克鲁兹旋毛虫感染的流行率 已导致实施血液筛查检测，以防止输血传播。循序渐进 昆虫媒介对美国最南端地区的入侵也增加了 原生的传播。Chagas病的诊断具有挑战性，因为基因型别的组合 因此，它的地理范围内的抗原变异，与 人类宿主，以及与其他寄生虫的交叉反应。血清学已成为诊断的支柱， 尤其是慢性感染，但上述挑战阻碍了血清学检测的准确性，如 在三角测量算法中通常使用多个化验来确定最终结果。 大多数感染克鲁兹旋毛虫的人生活在资源匮乏、不发达地区，那里有接触者 与媒介昆虫很难避免，但医疗保健相对原始，实验室基础设施 缺席。由于这些原因，作为诊断工具的快速护理点检测已变得越来越受欢迎 和恰加斯病的流行病学监测。目前的Chagas快速检测方法是有限的。 然而，在敏感性和特异性方面表现不佳，这主要是由于依赖 针对某些克氏锥虫菌株或谱系或感染阶段的重组抗原。至 截至目前，只有一种Chagas快速检测方法获得了FDA的批准。在这个项目中，我们建议开发一种快速测试 对于恰加斯病，基于从培养的克氏锥虫中半纯化的天然蛋白制剂，称为TESA (锥虫排泄/分泌抗原)。在申请者和其他人的初步研究中，TESA 免疫印迹显示临床敏感性和特异性在一系列基因型别中接近100%。 和血统。我们已经开发了一种提纯程序来丰富和浓缩抗原成分 的TESA，使其适用于侧向流动分析形式。我们已经在一个原型中使用了这种抗原 简化的侧向流动试验，其分析灵敏度高于FDA批准的快速试验和 在拉丁美洲广泛检测到克鲁兹旋毛虫感染。在第一阶段，我们将开发一个完整的TESA- 基于侧向流动的快速检测，适用于低资源环境中的护理点使用。特萨侧向流动试验 结果将使用现场友好、超便携、低成本的读取器进行读取，该读取器将提供客观的解释 并允许将数据无线上传到本地设备或远程服务器。第二阶段将支持完成 开发到商业阶段，临床评估和FDA提交的TESA侧向流动试验 恰加斯病的体外诊断。