In vivo imaging of T Cells using engineered antibodies and PET

描述（由申请人提供）：炎症和免疫反应在影响人类健康的大多数主要疾病中起核心作用，包括癌症、心血管疾病、自身免疫、神经炎症过程、糖尿病和其他疾病。此外，免疫调节疗法和过继性细胞疗法已成为癌症的有力治疗方法。监测和区分免疫细胞亚群（例如T和B淋巴细胞、巨噬细胞、中性粒细胞等）的能力非侵入性地在体内将是非常宝贵的有效治疗的发展。正电子发射断层扫描（PET）提供高灵敏度、非侵入性和定量成像，其可与基于抗体的探针组合以基于细胞表面表型提供体内组织和细胞的分子成像。此外，已经开发了具有最佳动力学的工程化抗体片段（微抗体和cys-双抗体），其能够通过免疫PET快速体内靶向和清除成像应用。在拟议的工作中，将开发免疫PET来解决免疫细胞亚群直接成像的挑战。工程化抗体片段将被优化用于表达CD 8的T淋巴细胞的体内检测、成像和定量，CD 8是细胞毒性T细胞的标志物。具体目标1将专注于生产稳定、优化的抗CD 8微抗体和来自大鼠抗小鼠单克隆抗体的cys-双抗体。具体目标2将建立最佳的成像剂，剂量和成像方案，用于正常（野生型）小鼠淋巴器官的可视化。具体目标3将重点关注正常和免疫刺激小鼠中T细胞的定量，以确定小鼠模型中的参数和检测限。一旦得到验证，CD 8 T细胞的免疫PET探针将成为研究小鼠模型中免疫过程的宝贵工具，从而更深入地了解活生物体中的免疫反应，并将为临床前模型和最终人类中免疫细胞亚群的成像和定量方法打开大门。

DESCRIPTION (provided by applicant): Inflammation and immune responses play a central role in most of the major diseases that impact human health, including cancer, cardiovascular disease, autoimmunity, neuroinflammatory processes, diabetes and other diseases. In addition, immunomodulatory therapies and adoptive cell therapies have become established as powerful therapeutic approaches in cancer. The ability monitor and distinguish immune cell subsets (e.g. T and B lymphocytes, macrophages, neutrophils, etc.) noninvasively in vivo will be invaluable to the development of effective treatments. Positron emission tomography (PET) provides highly sensitive, non- invasive and quantitative imaging, which can be combined with antibody-based probes to provide molecular imaging of tissues and cells in vivo based on cell surface phenotype. Furthermore, engineered antibody fragments (minibodies and cys-diabodies) have been developed with optimal kinetics enabling rapid in vivo targeting and clearance for imaging applications by immunoPET. In the proposed work, immunoPET will be developed to address the challenge of direct imaging of immune cell subsets. Engineered antibody fragments will be optimized for in vivo detection, imaging, and quantitation of T lymphocytes that express CD8, a marker that is a hallmark of cytotoxic T cells. Specific Aim 1 will focus on production of stable, optimized anti-CD8 minibodies and cys-diabodies derived from rat anti-mouse monoclonal antibodies. Specific Aim 2 will establish the optimal imaging agent, dose, and imaging protocol for visualization of the lymphoid organs in normal (wild-type) mice. Specific Aim 3 will focus on quantitation of T cells in normal and immune-stimulated mice to determine the parameters and limits of detection in mouse models. Once validated, immunoPET probes for CD8 T cells will be valuable tools to study immune processes in mouse models, providing a deeper understanding of immune responses in living organisms, and will open the door to broad methods for imaging and quantitating immune cell subsets in preclinical models and eventually humans.