Programed death ligand-1 (PD-L1) expression is currently the only predictive biomarker for cancer immunotherapy. Since PD-L1 expression in tumors is largely heterogeneous, in-vivo detection and quantification of PD-L1 in intact tumors is of major interest. Here we employ fluorescence lifetime (FLT) imaging for in-vivo detection and quantification of PD-L1 expression using an anti-PD-L1 antibody conjugated to IRDye800CW (αPDL1-800). We show that FLT imaging accurately identifies heterogeneous PD-L1 expression in tumors. Tumor areas of high PD-L1 levels were spatially correlated to significantly longer FLTs of αPDL1-800 and the distribution of PD-L1 in deep-seated (>1cm depth) tumors was achieved using FLT tomography.
Fluorescence imaging of cancers using continuous wave (CW) detection of receptor targeted probes offer poor sensitivity and specificity due to background autofluorescence and non-specific probe accumulation. Here we show that fluorescence lifetime (FLT) imaging can significantly improve tumor contrast using epidermal growth factor receptor (EGFR) and programed death ligand 1 (PD-L1) targeted probes in a preclinical model of human breast cancer. Our results suggest that these probes have significantly longer FLTs in tumors than in normal tissue and the FLT enhancement is receptor dependent. We also show potential for simultaneous quantification of EGFR and PD-L1 using in vivo FLT multiplexing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.