Transplantation Biology Research Division, State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.
Radiat Res. 2010 Feb;173(2):148-57. doi: 10.1667/RR0978.1.
Abstract CD4(+)CD25(+) regulatory T cells (Treg cells) are an important subset of T cells for keeping proper immune responses and tolerance. However, the effects of gamma radiation on CD4(+)CD25(high) Foxp3(+) Treg cells have not been examined previously. In the present study, we compared the sensitivity of mouse CD4(+)CD25(high) Foxp3(+) Treg cells and CD4(+)CD25(-) T cells to gamma radiation in vitro and in vivo. After C57BL/6 mice received a whole-body dose of 5 Gy gamma rays, the numbers of lymphocyte subsets in blood, lymph nodes, spleens and thymuses clearly decreased. However, gamma radiation significantly enhanced the ratios of CD4(+)CD25(high) Treg cells and CD4(+)CD25(high) Foxp3(+) Treg cells to CD4(+) T cells in the blood, lymph nodes, spleens and thymuses of mice. More dead cells were observed in CD4(+)CD25(-) T cells than in CD4(+)CD25(high) Treg cells or CD4(+)CD25(high) Foxp3(+) Treg cells when the cells were irradiated in vitro, indicating that CD4(+)CD25(high) Foxp3(+) Treg cells are more resistant to gamma radiation than other T cells. Moreover, a higher expression of Bcl-2 in CD4(+)CD25(high) Treg cells was detected compared with that in CD4(+)CD25(-) T cells. CD4(+)CD25(+) Treg cells from irradiated mice were functional, though their immunosuppressive ability was somewhat impaired compared to those from nonirradiated mice as determined by an in vitro assay. These results indicate that mouse CD4(+)CD25(+) Treg cells and CD4(+)CD25(-) T effector cells have different sensitivities to gamma radiation in mice.
摘要 CD4(+)CD25(+)调节性 T 细胞（Treg 细胞）是维持适当免疫反应和耐受的重要 T 细胞亚群。然而，γ 射线对 CD4(+)CD25(high)Foxp3(+)Treg 细胞的影响以前尚未被检测到。在本研究中，我们比较了体外和体内小鼠 CD4(+)CD25(high)Foxp3(+)Treg 细胞和 CD4(+)CD25(-)T 细胞对γ射线的敏感性。在 C57BL/6 小鼠接受全身 5 Gy γ射线照射后，血液、淋巴结、脾脏和胸腺中的淋巴细胞亚群数量明显减少。然而，γ 射线显著增加了小鼠血液、淋巴结、脾脏和胸腺中 CD4(+)CD25(high)Treg 细胞和 CD4(+)CD25(high)Foxp3(+)Treg 细胞与 CD4(+)T 细胞的比例。体外照射时，观察到 CD4(+)CD25(-)T 细胞中的死亡细胞多于 CD4(+)CD25(high)Treg 细胞或 CD4(+)CD25(high)Foxp3(+)Treg 细胞，表明 CD4(+)CD25(high)Foxp3(+)Treg 细胞比其他 T 细胞对 γ 射线更具抵抗力。此外，与 CD4(+)CD25(-)T 细胞相比，CD4(+)CD25(high)Treg 细胞中 Bcl-2 的表达更高。与未照射小鼠相比，照射小鼠的 CD4(+)CD25(+)Treg 细胞的功能正常，但体外测定其免疫抑制能力略有受损。这些结果表明，在小鼠中，CD4(+)CD25(+)Treg 细胞和 CD4(+)CD25(-)T 效应细胞对 γ 射线的敏感性不同。
