Imaging T cells using positron emission tomography (PET) would be highly useful for diagnosis and monitoring in immunology and oncology patients. There are, however, no obvious targets that can be used to develop imaging agents for this purpose. We evaluated several potential target proteins with selective expression in T cells, and for which lead molecules were available: protein kinase C isozyme θ (PKC θ), lymphocyte‐specific protein tyrosine kinase (Lck), zeta‐chain‐associated protein kinase 70 (ZAP70), and interleukin‐2‐inducible T‐cell kinase (Itk). Ultimately, we focused on Itk and identified a tool molecule with properties suitable for in vivo imaging of T cells: (5aR)‐5,5‐difluoro‐5a‐methyl‐N‐(1‐((S)‐3‐(methylsulfonyl)phenyl)(tetrahydro‐2H‐pyran‐4‐yl)methyl)‐1H‐pyrazol‐4‐yl)‐1,4,4a,5,5a,6‐hexahydrocyclopropa[f]indazole‐3‐carboxamide (23). Although it does not have the optimal profile for clinical use, this molecule indicates that it might be possible to develop Itk‐selective PET ligands for imaging the distribution of T cells in patients.

中文翻译：

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T细胞的PET成像：目标识别和可行性评估

使用正电子发射断层扫描（PET）对T细胞进行成像对免疫学和肿瘤学患者的诊断和监测非常有用。但是，没有明显的目标可用于为此目的开发显像剂。我们评估了几种可能在T细胞中选择性表达的潜在靶蛋白，并提供了可用的先导分子：蛋白激酶C同工酶θ（PKCθ），淋巴细胞特异性蛋白酪氨酸激酶（Lck），与Zeta链相关的蛋白激酶70（ ZAP70）和白介素2诱导性T细胞激酶（Itk）。最终，我们专注于Itk并确定了一种具有适合T细胞体内成像特性的工具分子：（5a R）‐5,5‐difluoro‐5a‐methyl‐ N‐（1 ‐（（S）‐3‐（甲磺酰基）苯基）（四氢-2H-吡喃-4-基）甲基）-1 H-吡唑-4-基）-1,4,4a，5,5a，6-六氢环丙烷[ f ]吲唑-3-羧酰胺（23）。尽管它不具有临床应用的最佳特性，但该分子表明可能开发出Itk选择性PET配体来对患者T细胞的分布进行成像。