Immunological studies of local antitumor effects by X ray irradiation

为了探讨放射治疗对荷瘤小鼠免疫功能的影响，研究了甲氧甲氧嘧啶肿瘤细胞移植后的全身免疫和局部免疫反应状况。对移植到腿上的肿瘤进行局部照射后，移植到对侧腿的未照射肿瘤的生长受到抑制。提示肿瘤局部照射后的抗肿瘤作用与小鼠脾淋巴细胞，特别是NK和t细胞的抗肿瘤免疫有关。同时，脾淋巴细胞NK活性升高。组织学结果显示，与未照射小鼠的肿瘤组织相比，未照射另一侧腿部肿瘤的对侧腿肿瘤组织中淋巴细胞浸润更早且更明显。免疫组织学分析显示，这些浸润淋巴细胞亚群主要由NK细胞和T细胞组成。进一步研究了肿瘤在辐照前组织中的生长情况。在任何高剂量或低剂量照射的情况下，照射前腿部的肿瘤生长都受到抑制。提示，在低剂量照射下，肿瘤免疫主要是抑制肿瘤生长，而在高剂量照射下，肿瘤生长的抑制主要是由抗肿瘤免疫和辐射对血管的损伤引起的，这一点在图像分析仪的组织学分析中得到了识别。

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.