重组人补体 C3 片段抑制小鼠内毒素休克

The inhibitory effect of recombinant human C3 fragment on murine endotoxic shock.

目的利用补体灭活片段ｉＣ３ｂ上含精氨酸－甘氨酸－天冬酰胺（ＲＧＤ）序列的重组蛋白，探索其抗炎治疗的应用价值。方法利用基因重组技术构建表达载体，在大肠杆菌中表达了含ＲＧＤ序列的重组蛋白（简称Ｃ３３），并进行体内外活性分析。结果电泳分析Ｃ３３分子量约１５０００，纯化后纯度可达９５％以上，氨基酸组成分析与理论计算值相符。低剂量醋酸苯汞刺激Ｕ９３７细胞可粘附于包被的Ｃ３３，抗ＣＤ１１ｂ的单克隆抗体可阻断这种粘附。提前静脉注射Ｃ３３可使小鼠内毒素休克的死亡率较未注射组明显降低。结论重组蛋白Ｃ３３可与ＣＤ１１ｂ／ＣＤ１８特异结合，Ｃ３３可降低小鼠的内毒素休克死亡率，作为预防性给药防治内毒素休克可能具有应用价值。

bjective\ To study the potentially practical use of C3 inactive fragment in anti inflammation.Methods A vector expressing RGD polypeptide derived from the αchain segment of human C3was constructed by using PCR and genetic engineering methods and a recombinant protein(namely C33) was expressed with high efficiency in E.coli.Results The analysis of SDS PAGE showed the molecular weight of C33 was about15KD.Its purity was above95%after purification.The amino acid composition was inconsistent with the theoretical values.U937cells stimulated by low dosage PMA adhered with coated C33,and the adhesion was blocked by anti CD 11b monoclonal antibody.After injection of purified C33 into mice which were consequently challenged by dead E.coli,the mortality of the endotoxic shock was significantly reduced.Conclusion C 33 can specifically bind to CD 11 b/CD 18.C33 as aligand for CD 11b/CD 18 might be potentially used as an anti inflammation agent.