FIG. 4.
Specific trafficking and proliferation of RNA CARs in tumor-bearing mice. (A) NOD/SCID/γc–/– (NSG) mice were injected IV with 106 Nalm-6 cells followed 7 days later with 5×106 T cells 4 hr after electroporation with the indicated mRNA constructs. The T cells had been stably transfected with a lentiviral construct to express firefly luciferase, and mice were imaged for bioluminescence. The graph indicates average of individual total photon flux±the standard error for each of the indicated groups (n=8). (B) CD19 RNA CARs exhibit increasing bioluminescence signal and anatomic distribution consistent with migration to sites of disease and CAR T-cell proliferation. Photon density heat maps on day 3 post injection suggest that mock T cells or T cells expressing RNA CARs with irrelevant specificity against mesothelin pool passively in the spleen (left flank on heat map) and do not increase in photon density, indicating a lack of proliferation. Note that the 5×106 cells produce a p/sec/cm2 flux of ∼2×107, equivalent among all groups immediately after injection. Saline-treated mice represent the background autoluminescence of 5×105 p/sec/cm2.