中文摘要：

目的研究低剂量x射线对人树突状细胞（DC）体外迁移能力影响并探讨其机制。方法分离人外周血单个核细胞（PBMC），以人GM-CSF和IL-4共同诱导分化为DC，于培养的第5天加入TNF—a促进成熟，在培养的第6天用x射线照射DC，受照剂量分别是0、0．05、0．1、0．2、0．5Gy，照射后48h收获DC；采用RT-PCR法及Westernblot法分别检测CCR7mRNA及蛋白表达水平；Transwell迁移实验法检测DC的体外迁移能力。结果与0Gy相比，0．2和0．5Gy照射后，CCR7mRNA的相对表达量显著高于其他剂量（t=14．72、4．72，P〈0．05）；0．2Gy照射后，CCR7蛋白表达量高于其他剂量（t=4．46，P〈0．05），DC迁移能力显著高于其他剂量（t=2．95，P〈0．05）；以抗CCR7单克隆抗体封闭CCR7蛋白活性，在接受同等剂量照射时，DC细胞迁移能力显著降低（t=4．63—8．96，P〈0．05）。结论受到0．2GyX射线照射的DC，体外迁移能力显著增强，其机制可能与受照后DC表达CCR7mRNA及蛋白水平升高有关。

英文摘要：

Objective To study the effect of low dose X-ray irradiation on the migration of human dendritic cells and its mechanism in vitro. Methods The human peripheral blood mononuclear cells （PBMC） were separated and treated with rhGM-CSF and rhIL-4 in order to differentiate them to dendritic cells （DC） in vitro. To enhance cell maturation, 50 mg/L TNF-ct was added into the medium at 5 d of culture. At 6 d of cell culture, DCs were radiated with X-rays of 0.05, 0.1, 0.2 and 0.5 Gy, respectively. At 8 d, the dendrite cells were collected for further analysis. The expressions of CC- Chemokine Receptor 7 （CCR7） mRNA and its protein were detected by RT-PCR and Western blot, respectively. Transwell culture inserts were used to measure the amount of migrated cells. Results After 0.2 and 0. 5 Gy radiation, the expression of CCR7 mRNA of DCs was remarkably increased （t = 14.72, 4.72,P 〈0.05）, but the expression of CCR7 protein in the DCs irradiated with O. 2 Gy was higher than that irradiated with other doses（ t = 4.46, P 〈 0.05 ）, meanwhile the amount of migrated DCs was obviously increased（t = 2. 95, P 〈 0.05 ）. Furthermore, DCs treated with anti-CCR7 monoclone antibody decreased the ability of radiation-induced migration （ t = 4. 63 - 8. 96, P 〈 0. 05 ）. Conclusions 0. 2 Gy X-ray irradiation significantly can enhance the migration ability of DCs in vitro, which may be correlated with the increase of CCR7 expression.