PET Probes Targeting Immune Cells for Imaging Tuberculosis

针对结核病成像的免疫细胞 PET 探针

• 批准号: 9517694
• 负责人: Carolyn J. Anderson
• 金额: $ 69.22万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2020-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9517694
• 关键词: AIDS/HIV problem; Affect; Africa; Animals; Antibiotics; Antigens; Asia; Autopsy; Bacillus (bacterium); Bacteria; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Characteristics; Chronic Obstructive Airway Disease; Clinical; Clinical Trials; Communicable Diseases; Country; Data; Development; Diagnosis; Diagnostic; Diffuse; Disease; Drug resistance; Dyes; Early Diagnosis; Exhibits; Flow Cytometry; Future; Glucose; Granuloma; HIV; Heterogeneity; Histology; Human; Image; Imaging Device; Immune; Immune Targeting; Immunohistochemistry; Immunologist; Individual; Infection; Infectious Agent; Inflammation; Inflammatory; Integrin alpha4beta1; Label; Lesion; Leukocytes; Life; Liver; Lung; Lung Inflammation; Lymphocyte; Macaca; Mannose; Methods; Modeling; Monitor; Morbidity - disease rate; Mycobacterium tuberculosis; Pathogenesis; Peptides; Persons; Pharmaceutical Preparations; Pharmacotherapy; Population; Positron-Emission Tomography; Prevalence; Pulmonary Tuberculosis; Radio; Radiopharmaceuticals; Regimen; Reporting; Rest; Risk; Scientist; Signal Transduction; Surface; T-Lymphocyte; Testing; Time; Tracer; Translating; Tuberculosis; Tuberculosis Vaccines; United States; Vaccines; World Health Organization; X-Ray Computed Tomography; base; cell type; cellular imaging; chemokine receptor; co-infection; experience; fluorodeoxyglucose; high risk; improved; inflammatory lung disease; latent infection; macrophage; molecular imaging; mortality; mouse model; multidisciplinary; mycobacterial; neutrophil; novel vaccines; preclinical trial; public health relevance; reactivation from latency; response; screening; serial imaging; small molecule; targeted agent; therapeutic vaccine; treatment optimization; treatment response; tuberculosis drugs; tuberculosis granuloma; uptake

 DESCRIPTION (provided by applicant): Tuberculosis (TB) is responsible for substantial morbidity and mortality worldwide. It is estimated that there are 9 million new cases of active TB every year, representing both primary TB and reactivation of latent infection, resulting in 1.3 million deaths. Only a small fraction (5-10%) of individuals infected with Mycobacterium tuberculosis (Mtb) develop active TB, with the rest being latently infected. Persons with latent infection exhibit immune responsiveness to mycobacterial antigens and no clinical signs of disease but remain at risk of reactivation to active TB. HIV co-infection increases the reactivation risk to 10% annually. The estimated 2 billion people worldwide (11.2 million in the U.S.) with latent infection are a significant reservoir of potential active, infectious TB. Due to he lack of an effective vaccine and increasing prevalence of drug resistance, there is no clear path for control, and ultimately elimination, in countries where TB is endemic. Since one third of the world's population is infected with Mtb, there is a critical need for better vaccines, treatments, and methods to determine those at highest risk of reactivation. TB predominately affects the lungs where tuberculosis lesions (granulomas) form that consist of lymphocytes, activated macrophages and neutrophils, as well as Mtb bacilli. TB granulomas are heterogeneous in terms of cellular composition, even within the same individual and may influence the ability of antibiotics to effectively sterilize individual lesions. This lesional heterogeneity is recapitulatd in our cynomolgus macaque model of TB. While [18F]-labeled 2-deoxy-2-fluoro- D-glucose (FDG) PET/CT imaging has been helpful in serially tracking Mtb infection and disease, as well as in monitoring the response to drugs in the macaque model and in humans, it does not specifically target the immune cells that are the primary populations in TB granulomas. Having agents that target key immune cells present in TB-infected lungs (macrophages, T cells, and neutrophils) will help differentiate resolving from progressing lesions, which will be invaluable in monitoring therapeutic responses as well as shortening pre- clinical and clinical trials of novel vaccines and chemotherapeutics. We hypothesize that PET imaging agents targeting specific populations of immune cells will provide more detailed information about the composition of granulomas in Mtb-infected cynomolgus macaques, such as the levels of neutrophils, T cells and activated macrophages that are important for early diagnosis of activated disease and assessing the response to drug treatment. In Aim 1, we will determine the mechanism of uptake for 64Cu-LLP2A, a VLA-4 targeted tracer, in TB granulomas of Mtb-infected macaques by a) serially imaging of infected macaques throughout disease with FDG and 64Cu-LLP2A; and b) injecting dye-LLP2A conjugates pre-necropsy to correlate immune cell localization by immunohistochemistry and flow cytometry with FDG imaging. Aim 2 will develop radiopharmaceuticals that specifically target macrophages by a) developing 18F-labeled small molecule antagonists of chemokine receptor type 2 (CCR2); and b) imaging Mtb-infected macaques with 18F-labeled mannose. In Aim 3 we will optimize neutrophil-specific probes based on 64Cu-labeled cFlFlF-based peptides by a) screening probes in a mouse model of inflammation to improve targeting and reduce clearance through the liver; and b) testing the uptake of radio- and dye-cFlFlF probes in neutrophils of Mtb-infected macaques. For Aim 4 we will investigate two to three of the most promising tracers developed in Aims 1-3 to monitor the cellular composition of TB lesions in macaques before, during, and after one chemotherapeutic (antibiotic) regimen, to determine if tracer uptake correlates with lesional histology and the efficiency of drugs to sterilize individual lesions.

 描述（由申请人提供）：结核病 (TB) 是全世界发病率和死亡率的主要原因。据估计，每年有 900 万新发活动性结核病例，包括原发性结核病和潜伏性感染的重新激活，导致 130 万例活动性结核病病例。只有一小部分 (5-10%) 感染结核杆菌 (Mtb) 的人发展为活动性结核病，其余的人为潜伏感染者。潜伏感染者对分枝杆菌抗原表现出免疫反应，并且没有疾病的临床症状，但仍面临活动性结核病重新激活的风险，全球估计有 20 亿人（美国为 1120 万人），导致重新激活的风险增加至 10%。 ）潜伏感染是潜在活动性传染性结核病的重要储存库，由于缺乏有效的疫苗和耐药性的增加，因此没有明确的控制和最终消除途径。在结核病流行的国家，由于世界上三分之一的人口感染了结核分枝杆菌，因此迫切需要更好的疫苗、治疗方法和方法来确定结核病复发风险最高的人群。结核肉芽肿）由淋巴细胞、活化的巨噬细胞和中性粒细胞组成，结核杆菌肉芽肿的细胞组成也不同，即使在同一细胞内也是如此。这种病变异质性在我们的食蟹猴结核病模型中得到了体现，而[18F]标记的2-脱氧-2-氟-D-葡萄糖（FDG）PET/CT。成像有助于连续追踪结核分枝杆菌感染和疾病，以及监测猕猴模型和人类对药物的反应，但它并不专门针对免疫系统使用针对结核感染肺部中存在的关键免疫细胞（巨噬细胞、T 细胞和中性粒细胞）的药物将有助于区分病变的消退和进展，这对于监测治疗反应也非常有价值。缩短新型疫苗的临床前和临床试验以及 我们追求针对特定免疫细胞群的 PET 显像剂将提供有关 Mtb 感染的食蟹猴肉芽肿组成的更详细信息，例如中性粒细胞、T 细胞和活化巨噬细胞的水平，这对于早期诊断很重要。在目标 1 中，我们将确定 64Cu-LLP2A（一种 VLA-4 靶向药物）的摄取机制。通过 a) 使用 FDG 和 64Cu-LLP2A 对受感染的猕猴在整个疾病过程中进行连续成像；b) 在尸检前注射染料-LLP2A 缀合物，通过免疫组织化学和流式细胞术与 FDG 关联免疫细胞定位目标 2 将通过 a) 开发专门针对巨噬细胞的放射性药物。 18F 标记的 2 型趋化因子受体 (CCR2) 小分子拮抗剂；b) 使用 18F 标记的甘露糖对 Mtb 感染的猕猴进行成像 在目标 3 中，我们将通过以下方法优化基于 64Cu 标记的 cFlFlF 肽的中性粒细胞特异性探针。 ) 在小鼠炎症模型中筛选探针，以提高靶向性并减少通过肝脏的清除；b) 测试摄取；对于目标 4，我们将研究目标 1-3 中开发的两到三种最有希望的示踪剂，以监测猕猴结核病病变之前、期间的细胞组成。在一种化疗（抗生素）方案后，确定示踪剂摄取是否与病变组织学和药物对个体进行绝育的效率相关病变。