Fig. 4

Examination of assays sensitivity when using the cryopreserved CAR/TCR T-cell flow cytometry quality controls. The cryopreserved flow cytometry quality control cells were thawed and diluted serially with the corresponding untransduced (UT) cells (1:1, 1:2, 1:4, 1:8, 1:16 and 1:32). The expression of transduction efficiency and identity markers: protein L, CD22-Fc (Siglec-2) and CD19-Fc for CD19/CD22 bispecific CAR-T cell (A), EGFR for FGFR4 CAR T-cell (B) and murine TCR-beta for KK-LC-1 TCR T-cell (C) were measured by flow cytometry. Data are shown as the correlation between the Log2 of the percentage of transduction efficiency and identity and the Log2 of dilution factor. The representative flow cytometry histograms or plots for protein L (A), EGFR (B) and TCR-beta (C) were gated on viable CD3⁺ cells. Data are representative of two independent experiments with similar results. For CD19/CD22 bispecific CAR T-cell, the study was performed in triplicates. For FGFR4 CAR T-cell and KK-LC-1 TCR T-cell, the study was performed in duplicates