ELISA for the production of IFN-γ and IL-4 in the supernatants of stimulated effector cells (7 days, irradiated HMECs, 50 U/mL IL-2). PBMCs were left unseparated or were negatively selected for CD8+ T cells as given for the experiments in Figure 6. Results are given as mean pg/mL cytokine ± SD of 3 independent experiments.