Immunological studies of local antitumor effects by X ray irradiation

点击翻译按钮获取中文摘要

In order to investigate the effect of radiotherapy on the immunity in the tumor-bearing mice, the status of general immunity and local immune reaction were studied after irradiation of transplanted Meth-A tumor cells.After local irradiation against the tumors transplanted onto the legs, the growth of the non-irradiated tumors transplanted into opposite side legs was suppressed. It was suggested that these anti-tumor effects after local tumor irradiation resulted from the anti-tumor immunity by mouse spleen lymphocytes, especially natural killer(NK)and t cells. At the same time, NK activity of spleen lymphocyte was also increased. The histological findings showed that lymphocyte infiltration into the tumor tissue was recognized at the earlier stage and more markedly in the non-irradiated opposite side leg tumor tissue of mice, of which leg tumors in another side were irradiated,than in the tumor tissue of non-irradiated mice. The immunohistological analysis revealed that the subpopulations of these infiltrated lymphocytes were composed of mainly NK and T cells.Still more, the growth of tumors at the pre-irradiated tissue were studied. Tumor growth at the pre-irradiated legs was suppressed in any cases of high-dose or low-dose irradiation.It is suggested that, in the low-dose irradiation, the anttumor immunity mainly acted on the suppression of the tumor growth, and in the high-dose irradiation, suppression of the tumor growth was mainly induced by both the antitumor immunity and the radiation damage to blood vessels which was recognized in the histological analysis by the image analyzer.