目的:利用毕赤酵母表达系统表达mSDF1γ/GMCSF融合蛋白,研究该融合蛋白对辐射小鼠的促造血增殖作用和免疫增强作用。方法：化学合成mSDF1γ/GMCS基因，构建携带该基因的表达载体，转化酵母后分泌表达重组融合蛋白，离子交换柱纯化，SDSPAGE和Western blotting分析鉴定。60Co γ射线照射制备小鼠辐射模型，以融合蛋白皮下注射进行治疗，观察辐射小鼠骨髓造血细胞的增殖活性及免疫细胞的趋化活性。结果：成功构建表达载体pPIC9K SDF1rhGMCSF1，转化毕赤酵母菌株GS115后表达融合蛋白mSDF1γ/GMCS，其相对分子质量为32 000，含量为78 ng/ml。融合蛋白治疗后，辐射小鼠骨髓单个核细胞增殖活性、GMCFU形成能力明显提高（均P<0.01）、骨髓细胞凋亡率非常明显地降低（P<0.05或P<0.01），小鼠外周血CD3+CD4+T细胞数显著高于辐射组和GMCSF治疗组（均P<0.05）。结论： mSDF1γ/GMCSF融合蛋白具有促进造血和免疫细胞增殖的双重活性，有望在抗肿瘤免疫和造血调控中开发成为有应用前景的新型细胞因子。

Objective: To express mSDF1γ/GMCS fusion protein in the Pichia pastoris expression system and investigate its in vivo promoting effects on hematopoiesis function and immune function. Methods: The mSDF1γ/GMCS fusion gene was chemically synthesized and was cloned into pichia expression vector; the vector was then transfected into Pichia pastoris expression system. Then the expressed products were detected by SDSPAGE，Western blotting and purified by ion exchange columns．Rat irradiation model was established by 60Co γ ray and were subcutaneously injected with the fusion protein. The hematopoietic and chemotactic activities of the fusion protein were investigated in vivo. Results: The expression vector pPIC9KSDF1LGMCSF was successfully constructed, and mSDF1γ/GMCS fusion protein was successfully expressed by Pichia pastoris strain GSl15．The molecular weight of the protein was about 32000 D, with a concentration of 78 ng/ml. The numbers of bone marrow mononuclear cells and GMCFU were significantly increased in rats after subcutaneous injection of the fusion protein (P<0.01). The apoptotic rate of bone marrow cells was significantly decreased（P<0.05 or P<0.01）, and the numbers of CD3+CD4+T lymphocytes in the peripheral blood were significantly increased (P<0.05). Conclusion: The mSDF1γ/GMCS fusion protein can improve the hematopoietic function and immune function in irradiated rats, which might be a promising cytokine for regulating hematopoiesis and antitumor immune response．

上海市自然科学基金资助项目（No. 06ZR14114）