低剂量X射线照射对小鼠肝癌H-22细胞膜相关抗原肽提取物抑瘤作用的影响

目的：观察低剂量X射线照射对小鼠肝癌H-22细胞膜相关抗原肽（TAP）提取物抑瘤作用的影响，为低剂量辐射与肿瘤疫苗联合治疗肿瘤提供实验依据。 方法：采用微酸洗脱法制备分子量≤3 000的细胞膜TAP提取物，皮下免疫小鼠，免疫前12 h给予75 mGy X射线全身照射，检测胸腺细胞周期时相、脾细胞Con A反应性及脾T细胞CD4、CD8亚组的变化，同时观察体内抑瘤效应。 结果：TAP提取物免疫小鼠后，移植肿瘤的发生率降低，平均出现时间延迟，生长速度减慢；脾细胞Con A反应性增强，胸腺细胞周期百分数无显著变化。小鼠免疫前12 h给予75 mGy全身照射可增强TAP提取物的抑瘤效应，与单纯TAP组相比，胸腺细胞S期百分数明显增加，脾细胞CD8+ T细胞百分数增高。 结论：低剂量辐射能进一步激发免疫系统功能，增强小鼠肝癌H-22细胞膜TAP提取物的抑制肿瘤作用。

Influences of low dose radiation on inhibitory effects of tumor-associated antigen peptide extract of H-22 hepatocarcinoma in mice

Objective To investigate the influences of low dose radiation (LDR) on the inhibitory effects of tumor-associated antigen peptide (TAP) extract of H-22 hepatocarcinoma in mice. Methods Mild acid elution method was applied to prepare TAP extract (MW≤3 000) from tumor cell membrane. The mice were given by whole-body irradiation (WBI) with 75 mGy X-rays 12 h before immunization with TAP extract. After immunization, the cell cycle progression of the thymocytes was detected with flow cytometry, the response of the splenocytes to Con A and the percentage of T cell subsets in splenocytes were analyzed. Meantime, the tumor-inhibited effect was observed in vivo. Results The present experiment showed that the TAP extract reduced the incidence of the transplanted tumor, delayed the average appearing time and decreased the growth speed of the tumor. The response of the splenocytes to Con A increased significantly as compared with that in the control group after mice were immunized with TAP extract, but there were no changes in the cell cycle progression of thymocytes. WBI with 75 mGy X-rays given to the mice 12 h before immunization could enhance the inhibitory effects of TAP extract, the percentage of S phase increased significantly as compared with that in the TAP extract group, and the percentage of the CD8~+ splenocytes increased. Conclusion The results suggest that LDR can efficiently activate the function of immune system, and enhance the inhibitory effects of the TAP extract.