Multiscale imaging of therapeutic anti-PD-L1 antibody localization using molecularly defined imaging agents

Journal of Nanobiotechnology

Ferenc A. Scheeren¹  Janneke D. M. Molkenboer-Kuenen²  Sandra Heskamp²  Peter J. Wierstra²  Martin Gotthardt²  Johan M. S. van der Schoot³  Martin ter Beest³  Kas Steuten⁴  Martijn Verdoes⁴  Iris M. Hagemans⁴  Olga Ilina⁴  Duco van Dalen⁴  Carl G. Figdor⁵ 

[1] Department of Dermatology, Leiden University Medical Centre, Leiden, The Netherlands;Department of Medical Imaging, Nuclear Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;Institute for Chemical Immunology, Nijmegen, The Netherlands;Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands;Institute for Chemical Immunology, Nijmegen, The Netherlands;Division of Immunotherapy, Oncode Institute, Radboud University Medical Center, Nijmegen, The Netherlands;

关键词: Fluorescence imaging;    Nuclear imaging;    Immune checkpoints;    Antibody;    Cancer;   

DOI  :  10.1186/s12951-022-01272-5

来源: Springer

【 摘 要 】

BackgroundWhile immune checkpoint inhibitors such as anti-PD-L1 antibodies have revolutionized cancer treatment, only subgroups of patients show durable responses. Insight in the relation between clinical response, PD-L1 expression and intratumoral localization of PD-L1 therapeutics could improve patient stratification. Therefore, we present the modular synthesis of multimodal antibody-based imaging tools for multiscale imaging of PD-L1 to study intratumoral distribution of PD-L1 therapeutics.ResultsTo introduce imaging modalities, a peptide containing a near-infrared dye (sulfo-Cy5), a chelator (DTPA), an azide, and a sortase-recognition motif was synthesized. This peptide and a non-fluorescent intermediate were used for site-specific functionalization of c-terminally sortaggable mouse IgG1 (mIgG1) and Fab anti-PD-L1. To increase the half-life of the Fab fragment, a 20 kDa PEG chain was attached via strain-promoted azide-alkyne cycloaddition (SPAAC). Biodistribution and imaging studies were performed with 111In-labeled constructs in 4T1 tumor-bearing mice. Comparing our site-specific antibody-conjugates with randomly conjugated antibodies, we found that antibody clone, isotype and method of DTPA conjugation did not change tumor uptake. Furthermore, addition of sulfo-Cy5 did not affect the biodistribution. PEGylated Fab fragment displayed a significantly longer half-life compared to unPEGylated Fab and demonstrated the highest overall tumor uptake of all constructs. PD-L1 in tumors was clearly visualized by SPECT/CT, as well as whole body fluorescence imaging. Immunohistochemistry staining of tumor sections demonstrated that PD-L1 co-localized with the fluorescent and autoradiographic signal. Intratumoral localization of the imaging agent could be determined with cellular resolution using fluorescent microscopy.ConclusionsA set of molecularly defined multimodal antibody-based PD-L1 imaging agents were synthesized and validated for multiscale monitoring of PD-L1 expression and localization. Our modular approach for site-specific functionalization could easily be adapted to other targets.Graphical Abstract

【 授权许可】

CC BY