低剂量照射对树突状细胞表型及功能的影响

目的研究低剂量照射对未成熟树突状细胞（DCs）大肠癌抗原吞噬能力、未成熟DC表型及体外刺激T细胞能力的影响。方法取健康人外周血,密度梯度离心获取单个核细胞。铺板贴壁法分离淋巴细胞,贴壁细胞在重组人粒细胞巨噬细胞集落刺激因子（rhGM-CSF）和白细胞介素4（rhIL-4）的作用下体外诱导5d后收获,并分别以0.1、0.2、0.5和1.0Gy的X射线照射24h。检测照射后未成熟DCs的表型、抗原吞噬能力及负载大肠癌肿瘤抗原信息的DCs在体外刺激T细胞的能力。结果流式细胞仪检测结果显示,0.2Gy照射组成熟DCs的CD40、CD80、CD83、CD86表型及抗原吞噬能力均明显高于对照组（未照射）及其他照射组（均P〈0.05）;体外刺激T细胞的能力随照射剂量的增加而减弱。结论低剂量照射能促进DCs抗原的吞噬能力和成熟,但会减弱体外刺激T细胞的能力。

Effects of Low-dose Irradiation on Phenotype and Function of Dendritic Cells

Objective To study the effect of low-dose irradiation on antigen presenting capacity,phenotype and stimulatory activity of immature dendritic cells（DCs）.Methods Peripheral blood mononuclear cells were isolated from healthy volunteers.DCs were induced from monocytes with granulocytemacrophage colony-stimulating factor（rhGM-CSF） and interleukin-4（rhIL-4） for 5 days.Immature DCs were harvested and exposed to various irradiation doses（0.1,0.2,0.5 and 1.0 Gy） from X ray for 24 hours.The variation of phenotypes was analysised for the irradiated cells antigen presenting capacity and stimulatory activity was analysised for the irradiated cells in vitro.Results The expressions of costimulatory molecules,such as CD40,CD80,CD83,CD86,and antigen presenting capacity of mature DCs cells irradiated at a dose of 0.2 Gy was higher than that in the non-irradiated DCs（P 0.05）.However,the stimulatory activity of immature DCs irradiated at higher doses reduced in vitro.Conclusion Low-dose irradiation can augment antigen presenting capacity and reduce T cell-activation capacity of DCs.