内毒素结合肽模拟肽P11的体外活性研究

目的对从噬菌体展示随机肽库筛选获得的内毒素结合肽模拟肽进行体外拈抗内毒素活性鉴定。方法采用FMOC固相合成法化学合成内毒素结合肽模拟肽P11，并进行拮抗内毒素活性和细胞毒性测定。结果亲和ELISA检测显示P11与LPS有较高的亲和力，通过生长曲线和流式细胞学分析细胞周期显示P11对人U937细胞生长无明显影响。流式细胞检测显示P11呈剂量依赖性抑制FITC—LPS与人外周血单核细胞（PBMC）结合。细胞因子生成抑制实验显示10μg/mlP11可显著抑制LPS诱导PBMC和U937细胞TNF—αmRNA转录和蛋白表达。结论体外活性鉴定结果表明化学合成的模拟肽P11可抑制LPS诱导的炎性反应。

Bioactivity of Mimetic Peptide of Endotoxin Binding Peptide in vitro

Objective To identify the bioactivity of mimetic peptide of endotoxin binding peptide obtained from phage display random peptide library in vitro. Methods Mimetic peptide of endotoxin binding peptide （named P11 ） was synthesized by the solidphase peptide synthesis method on a peptide synthesizer by F-moc chemistry, antiendotoxin bioaetivity and eytotoxicity of which were determined. Results Affinity ELISA assays indicated that P11 were able to bind LPS with high binding activity. Cytotoxicity were not observed through comparing growth curves and cell cycles of U937 cells incubated with or without P11. Then the effects of P11 on the binding of FITC- LPS to human peripheral blood monouclear ceils （PBMC） were examined by flow cytometry, and results showed that Pll dose-dependently inhibited FITC-LPS binding to PBMC. Further, 10 μg/ ml P11 significantly reduced LPS-induced TNF-α production in PBMC and U937 cells supernatants, as well as TNF-o~ mRNA expression in U937 cells. Conclusion These results demonstrate that synthetic mimetic peptide P11 attenuates LPS-induced inflammatory responses in vitro.