Polymyxin B inhibits induction of IL6 mRNA by LPS, but had no effect against peptidoglycan. Cells were treated with 100 μg/ml polymyxin B for 30 minutes before treatment with LPS (100 ng/ml) and PEP (10 μg/ml PEP) for 6 hours. Induction of IL6 gene expression by LPS treatment was significantly suppressed in the presence of polymyxin, but not PEP induction of IL6. Bars represent means and ± SEM of this normalized expression from 4 different replicates. Bars with different superscripts are different (P < 0.05).