电离辐射诱导免疫细胞旁效应的实验研究

目的 探讨不同剂量电离辐射在体外诱导免疫细胞的旁效应。方法用^3H-TdR掺入法观察未受照射的EL4细胞的增殖效应，用硝酸盐还原法测定受照射的J774A．1细胞分泌一氧化氮(NO)的含量。结果在受高、低剂量照射的抗原递呈细胞(J774A．1)和未受照射的T淋巴细胞(EL4)的共培养体系中，0．075Gy X射线照射的J774A．1细胞使EL4细胞的增殖增强，而2Gy X射线照射的J774A．1细胞则使EL4细胞的增殖抑制；较大剂量X射线照射后J774A．1细胞分泌NO量明显增多，可能影响共培养的T细胞的增殖反应。结论低剂量辐射可诱导兴奋性或有益的旁效应，其机理有待进一步阐明。

A study on the radiation-induced bystander effect of immune cells

Objective To study the radiation-induced bystander effect of immune cells in an in vitro system with different irradiation doses. Methods Incorporation of ~ 3H-TdR was used to observe the proliferation of EL-4 cells.Nitrate reduction was used to measure the amount of NO secreted by irradiated J774A.1 cells. Results The EL-4 cells when co-cultured with 0.075 Gy-irradiated J774A.1 cells were stimulated with up-regulated proliferation,while when co-cultured with 2 Gy-irradiated J774A.1 cells were suppressed with decreased proliferation.The possible mechanism of the differential effects of low versus high dose radiation was analyzed on the basis of difference in NO secreted by J774A.1 cells after low and high doses of X-irradiation. Conclusion~Bystander effect might participate in the realization of beneficial effect in the immune system caused by low dose radiation and its mechanism remains to be clarified.;