Journal of Nuclear Medicine, published on November 6, 2020 as doi:10.2967/jnumed.120.249078 18F-FAraG PET for CD8 Profiling of Tumors and Assessment of Immunomodulation by Chemotherapy Jelena Levi1*, Samuel Goth1, Lyna Huynh1, Tina Lam1, Tony L Huynh2, Brailee Schulte2, Juliet A Packiasamy1 1CellSight Technologies Incorporated, San Francisco, California; 2Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California; *Corresponding Author Jelena Levi, PhD 185 Berry street, San Francisco, 94107, CA Email:
[email protected] Running Title: [18F]F-AraG for CD8 profiling of tumors Financial statement: This work was supported by National Institutes of Health Grants NCI SBIR HHSN261201800024C (JL). Conflict of Interest Statement: JL, SG, LH, TL and JP are or were employed by CellSight Technologies. CellSight Technologies Incorporated is commercializing [18F]F-AraG as a PET tracer for evaluation of immune response in immunotherapy. No other potential conflicts of interest relevant to this article exist. ABSTRACT Majority of the clinical trials exploring various combinations of chemo- and immunotherapy rely on serial biopsy to provide information on immune response. The aim of this study was to assess the value of 18F-FAraG as a non-invasive tool that could profile tumors based on the key players in adaptive antitumor response, CD8+ cells, and evaluate immunomodulatory effects of chemotherapy. Methods. To evaluate the ability of 18F-FAraG to report on the presence of CD8+ cells within the TME, we imaged a panel of syngeneic tumor models (MC38, CT26, LLC, A9F1, 4T1 and B16F10), and correlated the signal intensity with the number of lymphocytes found in the tumors.