CD19 and melanoma: To assess the solid tumor activity of mCD19 CAR T cells in vivo, we established orthotopic, syngeneic models of B16 and B16-mCD19 melanomas and treated the tumors with either intratumoral mCD19 CAR T cells or mock T cells immediately following a sub-lethal lymphodepletive regimen of 5 Gy total body irradiation (TBI) previously shown to be necessary for CD19 CAR activity in immunocompetent models.19