NKTR and neoplasm: To better understand the mechanisms of improved antitumor activity and T cell trafficking with the ACT + NKTR-214 treatment, pmel-1 Thy1.1 + T cells were genetically modified to express firefly luciferase, which allows detection of T cells in vivo using bioluminescence imaging (BLI) to follow the biodistribution of the adoptively transferred T-cells and tumor-specific homing (Fig. 2a–c).