CD19 and cancer: To confirm these results in vivo, we tested the efficacy of h1218-CART19 against FMC63-CD19-epitope-masked cancer cells by engrafting immunodeficient NSG mice with 1 × 106 Nalm6-FMC63 cells on day -5 and randomized the mice to receive 0.75 × 106 UTD, FMC63-CART19, or h1218-CART19 T cells on day 0 (Fig. 3F).