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目的 探讨低剂量辐射对脐血T淋巴细胞膜分子表达、IL 2分泌及LAK细胞体外抗肿瘤活性的影响。方法 新鲜分离的脐血淋巴细胞及LAK前体细胞接受低剂量γ射线照射 ,分别用直接免疫荧光标记流式细胞术、MTT法及3H TdR释放实验检测T淋巴细胞膜分子的表达、IL 2分泌和LAK体外杀伤肿瘤靶细胞 (K5 6 2 ,HL 6 0 )活性。结果 ① 6 2mGyγ射线照射后 ,脐血淋巴细胞CD3、TCR CD3复合物、CD4、CD8分子表达显著上调 ,且均在 4～ 2 4h内随时间推移而逐步增强 ,CD4 CD8比值无显著性变化 ;② 6 2mGyγ射线照射后 ,脐血单个核细胞上清IL 2活性随培养时间推移逐渐增强 ,不同时间点比较差异均有显著性 (P <0 0 5 ) ;③脐血LAK细胞对K5 6 2和HL 6 0的杀伤活性与成人外周血相比差异无显著性 (P >0 0 5 ) ,接受低剂量辐射的脐血LAK细胞对K5 6 2和HL 6 0的细胞毒性显著高于非照射组 (P <0 0 1)。结论 低剂量辐射可促进脐血T淋巴细胞的成熟、活化和信号的转导及IL 2的分泌 ,增强脐血LAK杀伤肿瘤靶细胞的细胞毒活性 ,从而可能在脐血移植中加速免疫功能重建 ,增强移植物抗白血病效应
Objective To investigate the effect of low dose radiation on the expression of membrane molecule of T lymphocyte, secretion of IL 2 and anti-tumor activity of LAK cells in vitro. Methods Freshly isolated cord blood lymphocytes and LAK precursor cells were irradiated with low dose γ-rays. The expression of membrane molecules of T lymphocytes, the secretion of IL-2 and the secretion of IL-2 were detected by direct immunofluorescence labeling, MTT assay and 3H TdR release assay LAK in vitro killing of tumor target cells (K562, HL60) activity. Results ① The expression of CD3, TCR CD3 complex, CD4 and CD8 in umbilical cord blood lymphocytes were significantly increased after 6 2mGy γ-ray irradiation, and all of them were gradually increased over time from 4 to 24 hours with no significant change of CD4 CD8 ratio; (2) IL-2 activity of cord blood mononuclear cell supernatant increased gradually with the passage of time after irradiation with 6mGy gamma ray, and the difference was significant at different time points (P <0.05); ③ The effect of cord blood LAK cells on K562 (P> 0.05). The cytotoxicity of LAK cells exposed to low doses of radiation on K562 and HL60 cells was significantly higher than that of non-irradiated cells (P <0 0 1). Conclusion Low-dose radiation can promote the maturation and activation of T lymphocytes in cord blood and the signal transduction and secretion of IL 2, and enhance the cytotoxicity of LAK to tumor target cells in umbilical cord blood, which may accelerate the immune reconstitution in umbilical cord blood transplantation , Enhance graft anti-leukemia effect