Figure 2. Reduced cytokine production by p18^ink4c-deficient T cells.

T cells from p18^ink4c+/+ (dark gray symbols) or p18^ink4c−/− (light gray symbols) mice were stimulated with soluble anti-CD3 Ab (5 µg/mL) or anti-CD3 plus CTLA-4Ig (10 µg/mL). IL-2 (A and B) and IFNγ (C) in the supernatants of primary cultures was measured by ELISA at the indicated time points in A, at 24 hours in B, and at 72 hours in C. CD4+ T cells purified from the primary cultures in A–C were rested, restimulated with plate-bound anti-CD3 (1 µg/mL), and IL-2 secretion was measured by ELISA at 18 hours post-stimulation (D). Data are plotted as the mean +/−SEM of duplicate cultures, and are representative of 2–3 independent experiments.