Clinically compliant spatial and temporal imaging of chimeric antigen receptor T-cells.

The unprecedented efficacy of chimeric antigen receptor (CAR) T-cell immunotherapy of CD19 B-cell malignancy has established a new therapeutic pillar of hematology-oncology. Nonetheless， formidable challenges remain for the attainment of comparable success in patients with solid tumors. To accelerate progress and rapidly characterize emerging toxicities， systems that permit the repeated and non-invasive assessment of CAR T-cell bio-distribution would be invaluable. An ideal solution would entail the use of a non-immunogenic reporter that mediates specific uptake of an inexpensive， non-toxic and clinically established imaging tracer by CAR T cells. Here we show the utility of the human sodium iodide symporter (hNIS) for the temporal and spatial monitoring of CAR T-cell behavior in a cancer-bearing host. This system provides a clinically compliant toolkit for high-resolution serial imaging of CAR T cells in vivo， addressing a fundamental unmet need for future clinical development in the field.