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 查加斯病由寄生虫克氏锥虫感染引起，是最普遍的寄生虫病。 在西半球，有800万至1100万人感染了这种疾病，有7000多万人处于危险之中。的 感染是通过昆虫传播的，但也可以通过输血、器官移植、 移植或先天性的。在短暂的急性期之后，寄生虫在感染的携带者体内持续多年， 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，T.在移民人口中测得的克氏感染 已导致实施血液筛查检测以防止输血传播。逐步 这种昆虫媒介对美国最南端地区的入侵也增加了 本地传播。恰加斯病是具有挑战性的诊断，由于基因型的组合， 以及因此在其地理范围内的抗原性变异， 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主要手段， 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， 在三角测量算法中通常使用多个测定来建立最终结果。 大多数有T.克鲁兹感染者生活在低资源、不发达地区， 与病媒昆虫的接触是难以避免的，但医疗保健相对原始，实验室基础设施 无托叶由于这些原因，快速的即时检测作为诊断工具变得越来越受欢迎 和流行病学监测。目前这一代查加斯病快速检测是有限的 然而，在灵敏度和特异性方面， 对某些T.克氏菌株或谱系或感染阶段。到 迄今为止，只有一种查加斯病快速检测方法得到了FDA的批准。在这个项目中，我们建议开发一种快速检测方法， 对于恰加斯病，基于从培养的T. cruzi称TESA （锥虫排泄/分泌抗原）。在申请人和其他人的初步研究中，TESA 免疫印迹显示，在一系列基因型中，临床灵敏度和特异性接近100 和血统。我们已经开发了一种纯化程序来富集和浓缩抗原成分 的TESA，使其适用于侧流测定形式。我们已经用这种抗原做了一个原型 简化的侧向流测定，其表现出比FDA批准的快速检测更高的分析灵敏度， T.克鲁兹病毒在拉丁美洲蔓延。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。TESA侧流试验 结果将使用一种现场友好的、超便携的、低成本的阅读器来阅读，该阅读器将提供客观的解释 并且能够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 TESA侧流试验的商业化阶段开发、临床评价和FDA提交， 南美锥虫病的体外诊断。