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.

项目概要 查加斯病是由寄生虫克氏锥虫感染引起的，是最常见的寄生虫 该疾病在西半球感染了 8-1100 万人，其中超过 7000 万人处于危险之中。这 感染通过昆虫媒介传播，但也可以通过输血、器官传播 移植或先天性。经过短暂的急性期后，寄生虫在受感染的携带者体内持续存在多年， 通常无症状，但可引起心肌病和其他病理状况，导致严重的 发病率和死亡率。在美国，移民人群中克氏锥虫感染的流行率 导致实施血液筛查检测以防止输血传播。渐进的 昆虫媒介侵入美国最南端地区也增加了威胁 本地传输。由于基因型的组合，恰加斯病的诊断具有挑战性 因此，在其地理范围内存在抗原变异，与抗原之间存在复杂的免疫相互作用 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 特别是对于慢性感染，但上述挑战阻碍了血清学检测的准确性，例如 三角测量算法中通常使用多种测定来确定最终结果。 大多数有克氏锥虫感染风险的人生活在资源匮乏、不发达的地区，这些地区接触过克氏锥虫。 媒介昆虫的感染是难以避免的，但医疗条件相对简陋，实验室基础设施也很落后 缺席的。由于这些原因，快速的现场检测作为诊断工具变得越来越受欢迎 恰加斯病的流行病学监测。目前这一代恰加斯快速测试是有限的 然而，在敏感性和特异性方面均表现不佳，这主要是由于对 对特定克氏锥虫菌株或谱系或感染阶段具有特异性的重组抗原。到 迄今为止，只有一项 Chagas 快速检测已获得 FDA 批准。在这个项目中，我们建议开发一种快速测试 针对恰加斯病，基于从培养的克氏锥虫中提取的半纯化天然蛋白质制剂，称为 TESA （锥虫分泌/分泌抗原）。根据申请人和其他人的初步研究，TESA 免疫印迹显示对一系列基因型的临床敏感性和特异性接近 100% 和血统。我们开发了一种纯化程序来富集和浓缩抗原成分 TESA，使其适合用于侧流检测形式。我们已经在原型中使用了这种抗原 简化的侧流检测，比 FDA 批准的快速检测具有更高的分析灵敏度 在整个拉丁美洲广泛检测克氏锥虫感染。在第一阶段，我们将开发一个完整的 TESA- 基于侧流的快速检测，适合资源匮乏环境下的护理点使用。 TESA侧向层析测试 结果将使用现场友好、超便携、低成本的读取器读取，该读取器将提供客观的解释 并支持将数据无线上传到本地设备或远程服务器。第二阶段将支持完整 TESA 侧向层析测试的开发到商业阶段、临床评估和 FDA 提交 恰加斯病的体外诊断。