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) 是由结核分枝杆菌 (Mtb) 感染引起的，是全世界 5 岁以下儿童感染发病和死亡的主要原因。在结核病流行地区，全世界每年900万成人结核病病例中的绝大多数都居住在这些地区，5岁以下的儿童占患者总数的30-40%，而那些被感染的儿童往往病情更为严重，通常是致命的结核病。导致 5 岁以下儿童结核病致命的一个重要原因是该年龄组的标准结核病诊断效果不佳，特别是与成人相比。诊断不良会导致延误和漏诊，进而导致儿童发病率和死亡率增加。目前，我们需要一种简单、可靠的免疫诊断血液检测，以区分儿童结核性肺炎和非结核性肺炎。我们假设，针对 Mtb 肽的 CD8+ T 细胞检测可用于区分患有结核性肺炎的幼儿和非结核性肺炎的儿童。在这方面，CD8+ T 细胞优先识别严重 Mtb 感染的细胞，并且作为 OHSU 研究人员，我们在乌干达 < 5 岁儿童中观察到，在结核病儿童中检测到 Mtb 反应性 CD8+ T 细胞，而在无症状儿童中未检测到。结核分枝杆菌感染/暴露。总而言之，这些数据表明 CD8+ T 细胞与细菌负荷相关。与此同时，我们通过大规模抗原发现计划定义了 45 种免疫显性的、经过临床验证的 CD8 TB 抗原，这些抗原由 OHSU 独家授权给 ViTi, Inc.。为了开发改进的儿童诊断方法，在我们的 I 期研究中，我们使用生物信息学方法来定义这 45 种免疫显性 CD8 抗原中富含 HLA 高亲和力结合的区域。我们选择了代表这些可能含有免疫原性表位簇的区域的 166 个肽，并使用 IFN-α ELISPOT 测定测试了从有或没有潜伏性结核感染 (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 Mtb 感染的灵敏度进行了优化，另一种针对 Mtb 感染的特异性进行了优化，用于原型免疫诊断血液测试，我们随后将其分别称为 ViTi ONESENS 和 ViTi ONESPEC。在这个诊断准确性的 II 期提案中，我们将首先在因肺炎住院的 5 岁以下乌干达儿童队列中确定这些原型免疫诊断血液测试的敏感性和特异性。然后，为了进一步改进这些原型测试，我们将在 1 期研究中应用与 OHSU 授权给 ViTi Inc. 的其他新型免疫显性 CD8 抗原相同的策略，以创建改进的肽库，用于 ViTi TWOSENS 和 ViTi TWOSPEC 。最后，我们将确定 ViTi TWOSENS 和 ViTi TWOSPEC 在乌干达 5 岁以下因肺炎住院儿童的同一队列中的敏感性和特异性。