Time-dependent effects of IL-4, IL-13 and IFN-γ on SOCS-1 (A) and SOCS-3 (B) mRNA and protein expression. HASM were incubated with IL-4 (5 ng/ml), IL-13 (5 ng/ml) or IFN-γ (10 ng/ml) for 3, 6, 12 and 24 hours. SOCS-1, SOCS-3 and 18S mRNA expression was quantitated using real-time PCR. Data are expressed as the relative expression in SOCS/18S mRNA ratio and compared to unstimulated (vehicle) value of 1 at time 0, for 5 independent experiments. * p < 0.05 compared to cells treated with vehicle (ANOVA). SOCS-1 (C) and SOCS-3 (D) protein expression was assessed by Western analysis. Data are presented as mean ± SEM of densitometric values normalized to β-actin of 3–5 independent experiments.