Figure 1
Study timelines. (a) In vitro measurements of cell health and function of 89Zr labeled and unlabeled non-transduced (mock) T-cells and CAR T-cells were obtained in a separate experimental trial. Percent lysis of target Raji cells (cytotoxicity) and released cytokine levels in situ by the effector 89Zr-oxine labeled and unlabeled mock and CAR T-cells were measured 24 h after incubation of the effector cells with the target cells. Incubation of effector and target cells began 3 h post 89Zr-oxine labeling. Aliquots of 89Zr-oxine labeled and unlabeled mock and CAR T-cells were subcultured for in vitro viability and live cell number counts on the same in vivo scan timepoints. (b) In vivo biodistribution measurement of 89Zr-oxine labeled CAR T-cells began with CAR T-cell preparation and inoculation of NSG mice with Raji cells 12 days prior 89Zr-oxine labeling and IV administration. NSG mice were randomized to receive either a low (126.7 ± 2.5 kBq, 1.87 ± 0.04 × 106 cells, n = 3 mice), middle (542.6 ± 92.1 kBq, 7.14 ± 0.45 × 106 cells, n = 5 mice), or high (1491.7 ± 36.1 kBq, 16.83 ± 0.41 × 106 cells, n = 3 mice) dose of 89Zr-oxine labeled huLym-1-BB3z-CAR T-cells and underwent PET/MRI scans on day 0, 1, 2, and 5 time points, which corresponded to 3, 24, 48, and 120 h after CAR T-cell injection. Activity concentrations were obtained from PET scans and expressed as percent injected dose per gram of tissue of manually defined regions of interests that were identified on T1-weighted MRI anatomical scans. Coplanar PET and MRI scans were acquired simultaneously and were registered to the same space. Invasive ex vivo biodistribution was performed on day 6 post injection to complement the in vivo PET imaging study arm. 89Zr-oxine labeled and unlabeled CAR T-cells were subcultured for in vitro viability and live cell number counts on the same scan timepoints.
