Tumor Lysing Genetically Engineered T Cells Loaded with Multi-Modal Imaging Agents

Abstract

Genetically-modified T cells expressing chimeric antigen receptors (CAR) exert anti-tumor effect by identifying tumor-associated antigen (TAA), independent of major histocompatibility complex. For maximal efficacy and safety of adoptively transferred cells, imaging their biodistribution is critical. This will determine if cells home to the tumor and assist in moderating cell dose. Here, T cells are modified to express CAR. An efficient, non-toxic process with potential for cGMP compliance is developed for loading high cell number with multi-modal (PET-MRI) contrast agents (Super Paramagnetic Iron Oxide Nanoparticles – Copper-64; SPION-64Cu). This can now be potentially used for 64Cu-based whole-body PET to detect T cell accumulation region with high-sensitivity, followed by SPION-based MRI of these regions for high-resolution anatomically correlated images of T cells. CD19-specific-CAR+SPIONpos T cells effectively target in vitro CD19+ lymphoma.

Engineering and Design of Chimeric Antigen Receptors

“…Sleeping Beauty (SB) transposon is the most developed system of its kind to engineer CAR T cells, 79 complying with current good manufacturing practice (cGMP), 80 and is currently under investigation in the clinic (ClinicalTrials.gov: NCT00968760 and NCT01653717). Multiple SB enzymes81, 82 have been used to deliver more than one transgene from a multi-cistronic single plasmid83, 84 or multiple plasmids 85 . Others have developed CAR T cells using the piggyBac transposon system,86, 87, 88 which can integrate larger transgenes 89, 90.…”

Imaging of cell-based therapy using 89Zr-oxine ex vivo cell labeling for positron emission tomography

“…18 F-FDG also suffers from relatively rapid efflux after labeling, due to dephosphorylation of 18 F-FDG-6-phosphate, the phosphorylated form of 18 F-FDG that will be trapped within the cell [42,45,46]. 64 Cu-SPION has been recently developed as a PET-MRI multi-modal imaging nanoparticle that has potential benefits for tracking cells in vivo, taking advantage of both the high sensitivity of PET and detailed anatomical information of MRI [47]. However, the half-life of 64 Cu, although longer than that of 18 F, is still insufficient for tracking cells beyond several days after transfer.…”

New Developments in Imaging Cell-Based Therapy

“…This loading approach increased the T-cell viability to 80% after 4 d when 2.22 • 10 4 Bq (0.6 mCi) was loaded into 1 • 10 8 CAR 1 T-cells. However, no in vivo data with this compound have been published (15).…”