Methods Proprietary anti-CD19 CAR reagents and healthy donor transduced cells were provided by Kite Pharma for assay development: KIP-1 (16-6) rabbit mAb, KIP-3 (14-1) rabbit mAb, and CDL (anti-FMC63 scFv) mouse mAb. Commercially available antibodies include anti-human CD20 clone 2H7 mouse IgG2bk (Biolegend, 302302), anti-human CD22 clone S-HCL-1 mouse IgG2b (Biolegend, 363502), anti-human CD19 clone FMC63 mouse IgG2a (Sigma-Aldrich, MAB1794), anti-human CD19 clone LE-CD19 mouse IgG1 (Dako,...