Selective blockade of IFN-γ production in c-Rel–deficient T cells. Normal and c-Rel–deficient CD4+ T cells were purified and cultured at 106 cells/ml with or without plate-bound anti-CD3 mAb (2 μg/ml) and anti-CD28 mAb (2 μg/ml). Culture supernatants were collected 48 hours later and cytokine concentrations were determined by ELISA. Results are representative of two experiments.