Increased IFN-γ production upon mitogenic stimulation by tc-ptp^-/- splenic T cells. The mRNA levels for IFN-γ from splenic T cells from 19-day-old mice. The cells were either left unstimulated or stimulated overnight with 2.5 μg/mL ConA. Bars represent the mean values ± SE from triplicate cultures, with tc-ptp^-/- values (▪) shown as fold increase from those of age-matched tc-ptp^+/+ cells (□). Three separate experiments were performed and all gave similar results. The results shown are from one representative experiment.