Impaired proliferation and IL-2 secretion in pharmacologic cotreatment conditions. (A) Proliferative response and (B) IL-2 production of purified mature CD3⁺ T cells in the presence of inhibitors as specified. The panPKC LMWI and the PKA activator PDE4 LMWI reduce the proliferative and the IL-2 response significantly (P < .05). In combination, the additive effect on proliferation of the PDE4 LMWI and the panPKC LMWI (P = .067) is even stronger but not significantly different from the single compounds. Cells were left unstimulated or were stimulated with anti-CD3 (precoated at a concentration of 10 μg mL^–1) plus soluble anti-CD28 (1 μg mL^–1) or PDBu/ionomycin, as indicated. Results shown are the mean ± SD of at least 3 independent experiments.