Comparison of Tumor Non-specific and PD-L1 Specific Imaging by Near-Infrared Fluorescence/Cerenkov Luminescence Dual-Modality In-situ Imaging

  • Mol Imaging. 2024 Jun 14:23:15353508241261473. doi: 10.1177/15353508241261473.
Linhan Zhang  1 ,  Lianmeng Zhao  2 ,  Xue Lin  3 ,  Sheng Zhao  3 ,  Wenbin Pan  3 ,  Dandan Wang  3 ,  Zhongqi Sun  3 ,  Jinping Li  3 ,  Zonghui Liang  4 ,  Rongjun Zhang  5 ,  Huijie Jiang  3
Affiliations
  • 1. Department of Nuclear Medicine, The First Affiliated Hospital of Harbin Medical University, Harbin, China.
  • 2. Ultrasound Department, Heilongjiang Provincial Hospital, Harbin, China.
  • 3. Department of Radiology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China.
  • 4. Department of Radiology, Jing'an District Centre Hospital (Jing'an Branch of Huashan Hospital), Shanghai, China.
  • 5. Jiangsu Institute of Nuclear Medicine, Wuxi, China.
PMID: 38952401 DOI: 10.1177/15353508241261473
Abstract

Background: 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.

Objectives: To explore factors affecting labeled antibody visualization by PD-L1 specific and non-specific imaging of nude mouse tumors.

Methods: 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.

Results: 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.

Conclusion: 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.

Keywords
colorectal cancer; molecular imaging; programmed cell death 1 ligand 1.
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