抄録
We previously found that the suppressive effect of 0.5 Gy gamma rays irradiation on transplantation tumor growth in mice. To investigate the mechanisms of anti-tumor immune enhancement by low dose irradiation, in this study we examined the polarization of Th1/Th2 cytokine balance in splenocytes and peritoneal macrophages. Interferon (IFN)-gamma / interleukin (IL)-4 ratio produced by splenocytes of tumor-bearing mice was significantly increased by 0.5 Gy gamma rays irradiation. The capability to produce IL-12 upon IFN-gamma plus LPS stimulation of peritoneal macrophages from irradiated mice was also significantly increased. These results suggest that 0.5 Gy gamma rays activate cell-mediated immunity through Th1 predominance, resulting in the suppression of tumor growth. [J Radiat Res 44:390 (2003)]
