Figure 3

PSCA-CAR-engineered T cells specifically degranulate upon antigen recognition and kill PSCA-expressing tumor cells. PSCA-CAR T cells were co-cultured with mel526(PSCA) target cells or mel526(TARP) control cells. In a separate experiment PSCA-CAR T cells and Mock T cells were co-cultured with relevant target mel526(PSCA) cells. T cells (CD3⁺) were analyzed for CD107a expression (degranulation) by flow cytometry after 16 hours. Pooled data of CD107a expression on T cells from (A) PSCA-CAR T cells against mel526(PSCA) or mel526(TARP) target cells (n = 4), (B) PSCA-CAR T cells and Mock T cells against mel526(PSCA) target cells (n = 4). Asterisks indicate significance (*** p < 0.001, paired Student’s t-test). Error bars represent standard deviation from four individual donors run in triplicates. (C) PSCA-CAR T cells from three donors (#1, #2, #3) were co-cultured with luciferase-expressing mel526(PSCA) or mel526(TARP) target cells for 2 days. (D) PSCA-CAR T cells or Mock T cells from three donors (#4, #5, #6) were co-cultured with luciferase-expressing mel526(PSCA) for 4 days. Luciferase expression in target cells was then measured. Target cell viability was related to the luciferase signal for target cells not exposed to T cells. Error bars represent standard deviation from triplicate samples.