标记抗体是肿瘤学中出色的成像剂，可以非侵入性地可视化癌症相关抗原的表达水平。然而，在某些情况下，体内特异性抗体的肿瘤示踪剂摄取（TTU）可能不如非特异性IgG。通过裸鼠肿瘤的PD-L1特异性和非特异性成像探讨影响标记抗体可视化的因素。TTU是在 RKO 模型中观察到放射性核素 131I 或标记 Atezolizumab 和 IgG 的 NIRF 染料的 Cerenkov 发光 (CL) 和近红外荧光 (NIRF) 成像。注射NIRF染料标记的Atezolizumab和131I标记的IgG的混合物，通过NIRF/CL双模态原位成像在RKO和HCT8模型中观察到TTU。通过131I标记的Atezolizumab和IgG体外分布观察TTU。标记的IgG比Atezolizumab更集中在肿瘤中。 24至168小时内的NIRF/CL成像显示，TTU随时间逐渐下降，与NIRF成像相比，CL成像下降得更慢。体外分布数据显示，131I标记的IgG在任何时间点的TTU均高于131I标记的Atezolizumab。在比较裸体内肿瘤PD-L1表达时，非特异性IgG可能不适合作为Atezolizumab的对照在某些情况下通过标记抗体光学成像对小鼠进行观察。© 作者 2024。

Labeled antibodies are excellent imaging agents in oncology to non-invasively visualize cancer-related antigens expression levels. However, tumor tracer uptake (TTU) of specific antibodies in-vivo may be inferior to non-specific IgG in some cases.To explore factors affecting labeled antibody visualization by PD-L1 specific and non-specific imaging of nude mouse tumors.TTU was observed in RKO model on Cerenkov luminescence (CL) and near-infrared fluorescence (NIRF) imaging of radionuclide 131I or NIRF dyes labeled Atezolizumab and IgG. A mixture of NIRF dyes labeled Atezolizumab and 131I-labeled IgG was injected, and TTU was observed in the RKO and HCT8 model by NIRF/CL dual-modality in-situ imaging. TTU were observed by 131I-labeled Atezolizumab and IgG in-vitro distribution.Labeled IgG concentrated more in tumors than Atezolizumab. NIRF/CL imaging in 24 to 168 h showed that TTU gradually decreased over time, which decreased more slowly on CL imaging compared to NIRF imaging. The distribution data in-vitro showed that TTU of 131I-labeled IgG was higher than that of 131I-labeled Atezolizumab at any time point.Non-specific IgG may not be suitable as a control for Atezolizumab in comparing tumor PD-L1 expression in nude mice via labeled antibody optical imaging under certain circumstances.© The Author(s) 2024.