A CD8+ T cell diagnostic to identify children with pulmonary tuberculosis

CD8 T 细胞诊断可识别患有肺结核的儿童

• 批准号: 8601417
• 负责人: Deborah A. Lewinsohn
• 金额: $ 99.68万
• 依托单位: VITI, INC.
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8601417
• 关键词: 5 year old; Accounting; Acid Fast Bacillae Staining Method; Adult; Affinity; Algorithms; Antigens; Bacillus (bacterium); Binding; Bioinformatics; Biological Assay; Blood Tests; CD8 Antigens; CD8B1 gene; Cells; Cessation of life; Child; Childhood; Clinical; Cohort Studies; Collaborations; Contracts; Country; Data; Detection; Development; Diagnosis; Diagnostic; Disease; Early Diagnosis; Early treatment; Epitopes; Evaluation; Goals; Human; Immunological Diagnosis; Immunology; Individual; Infection; Interferons; Lead; Licensing; Morbidity - disease rate; Mycobacterium tuberculosis; National Institute of Allergy and Infectious Disease; Patients; Peptides; Performance; Phase; Pneumonia; Pulmonary Tuberculosis; Research; Research Personnel; Risk; Sensitivity and Specificity; Specificity; T cell response; T-Lymphocyte; Testing; Tuberculosis; Uganda; United States National Institutes of Health; Work; age group; base; cohort; diagnostic accuracy; enzyme linked immunospot assay; immunogenic; improved; insight; mortality; novel; phase 1 study; prevent; programs; prototype; public health relevance; validation studies

DESCRIPTION (provided by applicant): Tuberculosis (TB) disease, which results from infection with Mycobacterium tuberculosis (Mtb), is a leading cause of infectious morbidity and mortality in children < 5 years old worldwide. In TB endemic regions, in which the vast majority of the world's annual 9 million adult cases of TB disease reside, children < 5 years old account for 30-40% of the total patients and those children who are infected tend to have more severe, often fatal forms of TB. A significant contributor to the deadliness of TB in children < 5 years ol is the poor performance of standard TB diagnostics in this age group, especially as compared to adults. Poor diagnostics result in delayed and missed diagnoses, which in turn lead to increased morbidity and mortality in children. Currently, what is needed is a simple, robust immunodiagnostic blood test that will differentiate childhood TB pneumonia from pneumonia not due to TB. We hypothesize that the detection of CD8+ T cells directed toward Mtb peptides can be utilized to distinguish young children with TB pneumonia from those with pneumonia not due to TB. In this regard, CD8+ T cells preferentially recognize heavily Mtb-infected cells and as OHSU investigators, we have observed in Ugandan children < 5 years old, that Mtb-reactive CD8+ T cells are detected in children with TB and not detected in asymptomatic children with Mtb infection/exposure. Taken together, these data suggest that CD8+ T cells correlate with bacterial burden. In parallel, we have defined 45 immunodominant, clinically-validated CD8 TB antigens through our large scale antigen discovery program that are exclusively licensed to ViTi, Inc. from OHSU. To develop an improved diagnostic for children, in our Phase I study, we used a bioinformatic approach to define regions enriched for high affinity binding to HLA within these 45 immunodominant CD8 antigens. We selected 166 peptides representing these regions likely to contain clusters of immunogenic epitopes, and using IFN-? ELISPOT assay, tested the recognition of these peptides by CD8+ T cells isolated from individuals with and without latent TB infection (LTBI). From these data, we selected sets of peptides comprising two peptide pools; one optimized for sensitivity and one for specificity for Mtb infection to be used in prototype immunodiagnostic blood tests, which we will subsequently refer to as ViTi ONESENS and ViTi ONESPEC, respectively. In this Phase II proposal of diagnostic accuracy, we will first determine the sensitivity and specificity of these prototype immunodiagnostic blood tests, in cohorts of Ugandan children < 5 years old hospitalized with pneumonia. Then to further improve upon on these prototype tests, we will apply the same strategy we used in the Phase 1 study to additional novel immunodominant CD8 antigens licensed by OHSU to ViTi Inc. to create improved peptide pools to be used in ViTi TWOSENS and ViTi TWOSPEC. Finally, we will determine the sensitivity and specificity of ViTi TWOSENS and ViTi TWOSPEC in the same cohorts of Ugandan children < 5 years old hospitalized with pneumonia.

描述（由申请人提供）：结核病（TB）疾病是由结核分枝杆菌（MTB）感染引起的，是全球<5岁儿童感染性发病和死亡率的主要原因。在结核病地区，世界上绝大多数900万成人结核病病例中的绝大多数居住在该地区，儿童<5岁的儿童占总患者的30-40％，而被感染的儿童往往往往具有更严重的，通常是致命的结核病形式。在<5岁的儿童中，结核病的致命性的重要原因是该年龄段的标准结核病诊断表现不佳，尤其是与成年人相比。诊断不佳导致延迟和错过的诊断，进而导致儿童发病率和死亡率增加。目前，需要的是一种简单，可靠的免疫诊断血液检查，它将不明显地将儿童结核病与肺炎区分开来。我们假设可以利用针对MTB肽的CD8+ T细胞的检测来区分TB肺炎的幼儿和肺炎的儿童，而不是由于TB而引起的。在这方面，CD8+ T细胞优先识别了MTB感染的细胞，并且作为OHSU研究者，我们已经观察到在<5岁的乌干达儿童中，MTB反应性CD8+ T细胞在TB的儿童中被检测到MTB感染/暴露/暴露/暴露于MTB的儿童中。综上所述，这些数据表明CD8+ T细胞与细菌负担相关。同时，我们通过我们的大规模抗原发现程序定义了45个免疫主导，临床验证的CD8 TB抗原，这些抗原计划仅从OHSU获得Viti，Inc。的许可。为了开发改进的儿童诊断，在我们的I期研究中，我们使用了一种生物信息学方法来定义这45种免疫降低CD8抗原中与HLA高亲和力结合的区域。我们选择了代表这些区域的166个肽，可能包含免疫原性表位簇，并使用IFN-？ ELISPOT分析测试了从有或没有潜在TB感染的个体（LTBI）的个体中分离出的CD8+ T细胞对这些肽的识别。从这些数据中，我们选择了包含两个肽池的肽组。一种针对敏感性进行了优化，一种用于MTB感染的特异性，用于原型免疫诊断血液测试，随后我们将分别称为Viti Onesens和Viti Onespec。在此II阶段的诊断准确性提案中，我们将首先确定这些原型免疫诊断血液测试的灵敏度和特异性，在患有肺炎住院的乌干达儿童<5岁的乌干达儿童中。然后，为了进一步改进这些原型测试，我们将应用与1期研究中使用的相同策略，以其他新型的免疫降低CD8抗原（由OHSU授权到Viti Inc.）创建改进的肽库，以在VITI TWOSENS和VITI TWOSPEC中使用。最后，我们将确定在同一群乌干达儿童<5岁的乌干达儿童中，Viti Twosens和Viti Twospec的敏感性和特异性，患有肺炎。