Effect of blocking IL-13α2 on cytokine-mediated inhibition of IL-13-induced STAT6 phosphorylation. HASM were pre-treated with IFN-γ (10 or 100 ng/ml), IL-4 (5 ng/ml) or IL-13 (5 ng/ml) 24 hours prior to IL-13 stimulation in the presence or absence of neutralizing concentration of anti-IL-13α2 polyclonal antibody (5 μg/ml). Phosphorylated STAT6 expression was assessed by Western analysis. A and C: Representative Western blots. B and D: Band densities were measured and the densitometric values were normalized to the IL-13-stimulated value. Data are shown as the mean values ± SEM of three independent experiments. * p < 0.05 (ANOVA).