Enhanced immune recognition of tumor cells by CD27-bearing CAR-T cells. (A) FR surface expression on human ovarian cancer and breast cancer cell lines by flow cytometry. FR-specific mAb MOv18 was used to measure FR expression on tumor cell lines (open empty histogram), compared with a matched isotype Ab control (filled gray histogram). (B) Antigen-specific cytokine production by FR CAR-transduced T cells. IFN-γ secretion of FR-z and 27z CAR-transduced T cells after 20 hours' coculture with the indicated tumor lines at a 1:1 ratio. Untransduced T cells (UNT) and CD19-27z CAR-T cells were used as negative controls. Anti-CD3/28 beads stimulation served as positive control. CD19⁺K562 cell line was used as positive target control for CD19 CAR. Results are expressed as a mean and SD of triplicate wells from 1 of at least 3 separate experiments.