人重组C3片段通过IL-2自分泌效应对CTLL-2细胞产生促增殖作用

Stimulating effect of recombinant human C3 fragment on CTLL 2 cells by a pathway of autocrine of interleukin 2

目的研究补体Ｃ３片段的体外生物学活性及其作用机理，进一步探讨Ｃ３片段与免疫细胞的关联。方法利用重组ＤＮＡ技术表达纯化Ｃ３活性片段（命名为Ｃ３３），观察其对ＩＬ－２依赖性的小鼠杀伤性Ｔ细胞株ＣＴＬＬ－２细胞的促增殖效应，并通过抗体封闭途径和分子杂交技术研究Ｃ３３作用的机理。结果发现Ｃ３３蛋白对ＣＴＬＬ－２细胞具有明显的促增殖作用，并呈剂量依赖关系；这一作用能够部分地被抗小鼠ＣＤ１１ｂ抗体所封闭，能够完全被抗小鼠ＩＬ－２抗体所封闭；分子杂交显示Ｃ３３蛋白能够明显刺激ＣＴＬＬ－２细胞的ＩＬ－２ｍＲＮＡ表达。结论人重组Ｃ３片段Ｃ３３可通过ＩＬ－２的自分泌效应对ＣＴＬＬ细胞产生促增殖作用，补体受体ＣＲ３参与这一作用。

Objective To study the in vitro bioactivity of complement C3 fragment and research for its mechanism. Methods A bioactive fragment of C3 with RGD sequence(namely C33)was expressed and purified by using recombinant DNA techniques and its effect on the murine cytotoxicity T cell line(CTLL 2 cells)was studied.In order to research the mechanism of the C33,different antibodies were used to block the effects of C33 and molecular hybridization technique was used to study the transcription of IL 2 mRNA. [WT5”HZ〗 Results It was showed that the C33 proteins could dose dependently stimulate the proliferation of CTLL 2 cells.The effect of C33 could be partly inhibited by anti mouse CD11b antibody and completely inhibited by anti mouse interleukin 2(IL 2) antibody.RNA hybridization determined that C33 protein stimulated significantly the expression of IL 2 mRNA in CTLL 2 cells. [WT5”HZ〗 Conclusions \ The results suggest that recombinant human C3 fragments possess stimulating effect on CTLL 2 cells by a pathway of autocrine of IL 2 and the complement receptor CR3 involved their interaction.