293 cells were transfected with FMC63-scFv and RFP tag. 2e5 of the cells were first stained with B. Human CD19 (20-291) Protein, Fc Tag, low endotoxin (Super affinity) (Cat. No. CD9-H5251, 3 µg/ml) and C. Human Fc Tag Protein Control, followed by FITC-conjugated Anti-human IgG Fc Antibody. A. Non-transfected 293 cells and C. Human Fc Tag Protein Control were used as negative control. RFP was used to evaluate CAR (anti-CD19-scFv) expression and FITC was used to evaluate the binding activity of Human CD19 (20-291) Protein, Fc Tag, low endotoxin (Super affinity) (Cat. No. CD9-H5251).