Morath Volker, Fritschle Katja, Warmuth Linda, Anneser Markus, Dötsch Sarah, Živanić Milica, Krumwiede Luisa, Bösl Philipp, Bozoglu Tarik, Robu Stephanie, Libertini Silvana, Kossatz Susanne, Kupatt Christian, Schwaiger Markus, Steiger Katja, Busch Dirk H, Skerra Arne, Weber Wolfgang A
Department of Nuclear Medicine, TUM University Hospital, School of Medicine and Health, Technical University of Munich, Munich, Germany.
Institute for Medical Microbiology, Immunology and Hygiene, School of Medicine and Health, Technical University of Munich, Munich, Germany.
Nat Biomed Eng. 2025 Jun 13. doi: 10.1038/s41551-025-01415-7.
The clinical translation of cell- and gene-based therapies is limited by the lack of non-invasive, quantitative and specific whole-body imaging tools. Here we present a positron emission tomography reporter system based on a membrane-anchored anticalin protein that binds a fluorine-18-labelled lanthanide complex with picomolar affinity via a bio-orthogonal interaction. The reporter was introduced into therapeutic cells, including CAR T cells and adeno-associated virus-transduced cells. In vitro, reporter expression conferred >800-fold higher radioligand binding versus controls. In mice, the radioligand demonstrated rapid renal clearance, showed no off-target accumulation and enabled high-contrast detection of as few as 1,200 CAR T cells in the bone marrow. Longitudinal positron emission tomography imaging over 4 weeks revealed precise tracking of CAR T cell expansion and migration, with signal intensity correlating linearly with flow cytometry data. The system also enabled the quantitative imaging of in vivo gene transfer using an adeno-associated viral vector. This depth-independent whole-body imaging platform offers a powerful tool for monitoring therapeutic cell dynamics and gene delivery in preclinical and potentially clinical settings.
基于细胞和基因的疗法的临床转化受到缺乏非侵入性、定量且特异性的全身成像工具的限制。在此，我们展示了一种基于膜锚定抗钙素蛋白的正电子发射断层扫描报告系统，该蛋白通过生物正交相互作用以皮摩尔亲和力结合氟-18标记的镧系元素复合物。该报告基因被引入治疗性细胞中，包括嵌合抗原受体（CAR）T细胞和腺相关病毒转导的细胞。在体外，与对照相比，报告基因的表达使放射性配体结合增加了800倍以上。在小鼠中，放射性配体显示出快速的肾脏清除率，未出现脱靶积累，并且能够在骨髓中高对比度检测低至1200个CAR T细胞。在4周内进行的纵向正电子发射断层扫描成像揭示了对CAR T细胞扩增和迁移的精确追踪，信号强度与流式细胞术数据呈线性相关。该系统还能够使用腺相关病毒载体对体内基因转移进行定量成像。这个不依赖深度的全身成像平台为在临床前以及潜在的临床环境中监测治疗性细胞动态和基因递送提供了一个强大的工具。
