Relevant up-regulation of IκBα mRNA by LPS and expression of oscillatory kinetics under prolonged stimulation. (A) PMNs were incubated with 1 μg/mL LPS, 20 ng/mL GM-CSF (CSF), or 10^–7 M DEX for the indicated time points and synthesis of IκBα mRNA was assessed by quantitative RT-PCR (n = 6 for LPS; n = 3 for GM-CSF and DEX). Total RNAs were isolated according to a Qiagen protocol including DNase treatment; quantification was checked for each sample using probes for GAPDH mRNA. The oligonucleotides used for IκBα are described in “Materials and methods.” The values represent mean ± SEM. (B) To investigate the time kinetics of LPS-induced expression of IκBα, mRNA cells were treated up to 180 minutes with 1 μg/mL LPS (n = 3). A representative figure is shown.