Differential effector functions of tumor-specific human primary T cells overexpressing IL-2, IL-7, IL-15, or IL-21. (A) Antigen-specific cytotoxic activity of transduced T cells. On day 6 after AAPC stimulation, T cells were assessed for cytolytic potential in a 4-hour chromium-release assay using EL4-hCD19 and EL4-hPSMA as the relevant and irrelevant targets (T). Effectors (E) were defined as 19z1⁺CD8⁺ T cells. Data are average (± SEM) from 4 donors. *P < .05, ^#P < .005 versus 19z1-ΔLNGFR. (B) Intracellular expression of granzyme A by transduced T cells. On day 7 after AAPC stimulation, T cells were analyzed by flow cytometry for the cytolytic molecule granzyme A. Average percent granzyme A⁺ T cells (± SEM) of 19z1⁺CD4⁺ and 19z1⁺CD8⁺ subsets from 7 donors is indicated. (C) IFN-γ, TNF-α, and IL-2 expression by transgenic T cells. On day 7 after AAPC stimulation, 19z1⁺ T cells were purified and treated with no stimulation (unstimulated) or anti-CD3/anti-CD28 antibodies (CD3/CD28) in the presence of brefeldin A and monensin. After 6 hours, T cells were analyzed for cytokine expression by intracellular flow cytometry. The percentage of CD4⁺ (top row) or CD8⁺ (bottom row) T cells that express the indicated effector cytokine from 5 donors is indicated. Horizontal bar indicates average. *P < .05, **P < .01, ^#P < .005 versus 19z1-ΔLNGFR.