(KIRAMS/송경희, 유상영*, 송지영*)
PURPOSE
In contrast to high-dose therapeutic irradiation, definitive research detailing the physiological effects of low-dose irradiation is limited. Notably, the immunological response elicited after low-dose irradiation remains controversial.
MATERIALS AND METHODS
Female C57BL/6 mice were whole- body-irradiated with a single or three daily fractions up to a total dose of 0.1, 1, or 10 cGy. Blood and spleen were harvested 2, 7 and 14 days after irradiation.
RESULTS
The splenic CD4+ T cell subpopulations were temporarily increased at 2 days after single or fractionated irradiation, whereas the percentage of dendritic cells (DC) and macrophages was decreased. Whereas CD8+ T cell populations were decreased in single-dose irradiated mice at day 7, early and sustained reduction of CD8+ T cell numbers was observed in fractionated- dose-irradiated mice from day 2 until day 14. In addition, single-dose irradiation resulted in a Th1 cytokine expression profile, whereas fractionated-dose irradiation drove a Th2 shift. Additionally, increased expression of immune-related factors was observed at early time-points with single-dose irradiation, in contrast to the dose-independent induction following fractionated-dose irradiation.
CONCLUSIONS
Our results demonstrate that low-dose irradiation modulates the immune response in mice, where the sensitivity and kinetics of the induced response vary according to the dosing method.
Author Information
Song KH1, Kim MH, Kang SM, Jung SY, Ahn J, Woo HJ, Nam SY, Hwang SG, Ryu SY, Song JY.
1Division of Radiation Cancer Research, Korea Institute of Radiological & Medical Sciences , Seoul , Republic of Korea.