目的　获得稳定表达人衰变加速因子 (humandecay acceleratingactivity ,hDAF)的中国仓鼠卵巢 (Chineseham sterovary ,CHO)细胞系 ,观察在补体活化情况下 ,hDAF对异种细胞的保护作用。方法　构建真核表达载体DAF pcDNA3 .1,用脂质体转染法将其导入CHO细胞 ,有限稀释法筛选稳定表达hDAF的单细胞克隆 ,流式细胞仪检测hDAF的表达 ,C3沉积实验和51 Cr释放法测定其促补体衰变活性。结果　成功构建了真核表达载体DAF pcDNA3 .1,并获得了表达hDAF的单细胞克隆 ,表达hDAF的CHO能减少补体C3的沉积 ,减弱补体的杀伤作用。结论　获得在细胞膜上稳定表达具功能活性的hDAF的CHO克隆 ,为进一步研究其结构与功能的关系准备了条件。 Objective To obtain the Chinese hamster ovary (CHO) cell line stably expressing human decay accelerating factor (hDAF), and to observe the protective effect of hDAF on xenogeneic cells under the condition of complement activation. Methods The eukaryotic expression vector DAF pcDNA3.1 was constructed and transfected into CHO cells by lipofection. The single cell clones stably expressing hDAF were screened by limiting dilution, the expression of hDAF was detected by flow cytometry, Cr release assay to determine its complement promoting activity. Results The eukaryotic expression vector DAF pcDNA3.1 was successfully constructed and a single cell clone expressing hDAF was obtained. CHO expressing hDAF reduced the deposition of complement C3 and attenuated the killing effect of complement. Conclusion Obtaining CHO clone stably expressing hDAF with functional activity on the cell membrane provides a condition for further study on the relationship between its structure and function.