Objective To compare the in vitro inhibition activity of three mimic peptides at lipopolysaccharide binding protein (LBP)／CD14 binding sites for LPS-induced inflammatory response.Methods Enzyme-linked immunoSorbent assay(ELISA)was applied for the detection of the affinity between the mimic peptides and CD14 as well as the competitive inhibition activity of LBP.Mature U937 cells induced by PMA were co-cultured with LPS and intervened by mimic peptide.The effect of the mimic peptide on the TNF-α expression of U937 was detected by RT-PCR.Alveolar macrophages(AMs)of rats were co-cultured with FITC-LPS，and mimic peptide intervention was conducted.The effect of the mimic peptide on combination of LPS and AMs was observed by fluorescence microscope . Results Affinity between No.1 mimic peptide(FHRWPTWPLPSP，10 μg／mL)and CD14 was significantly higher than those of No.2 and No.3(20.3±4.1 11.8±2.4 and 13.7±3.3，Plt;0.01 or Plt;0.05).The competitive inhibitory activity of No.1 mimic peptide(10 μg／mL)for LBP was higher than those of No.2 and No.3[(57.2土11.2)％ vs(39.4±9.7)％ and(37.9±8.3)％ ，Plt;0.01].All of the three mimic peptides(10 μg／mL)could significantly inhibit the LPS-induced expression of TNF-α by U937 at mRNA level(Plt;0.01 or Plt;0.05)，moreover，the inhibitory activity of No.1 peptide was the highest(0.239±0.053 vs 0.406±0.112 and 0.493±0.121，Plt;0.01).In addition，No.1 mimic peptide markedly inhibited LPS combination with rat lung AMs(2157±514 vs 2763±453，plt;0.01).Conclusion No.1 mimic peptide(FHRWPTWPLPSP)have a relatively higher affinity with CD14 and high competitive inhibition activity for LBP，therefore it have the potential ability of anti-inflammatory response induced by LPS.
