The relationships between irradiation and B7.1 costimula-tory molecule expression of human tumor cells were studied to explore reason of tumorcell's immunogenicity enhanced. The effect of γ rays irradiation on B7.1 molecule ex-pression in human tumor cells which was irradiated with 30, 40, 50, 60Gy γ rays wasinvestigated. At 24, 48, 72, 96h after irradiation the change of B7.1 molecule wasmeasured by flow cytometry (FCM) with immunofluorescence technique. B7.1mRNAwas determined by reverse transcription polymerase chain reaction(RT-PCR). Thecytotoxicity of lymphocyte upon tumor target cell after exposure was measured by3H-thymidine(3H-TdR) release assay. The results showed that after γ rays irradiationSMMC-7721 hepatoma, PC-12 pheochromacytoma, A-459 lung cancer cell lines ex-press B7.1 costimulatory molecule. RT-PCR showed that expression of B7.1 moleculein SMMC-7721 is resulted from B7.1mR NA expression. Furthermore, B7.1 moleculemembrane expression after γ rays irradiation is shown to enhance the cytotoxicityof lymphocyte. The data could explain the enhanced immunogenicity of tumor cellsafter irradiation, and could lead to new immunotherapy protocols. The experimentssuggested that γ rays irradiation could selectively induce human tumor cells to expressB7.1 costimulatory molecules and enhance immunogenicity of tumor cell.%为研究电离辐射与人肿瘤细胞B7.1分子表达之间的关系,探讨肿瘤细胞在照射后免疫原性增强的机理.采用间接免疫荧光-流式细胞仪测定技术,用30、40、50、60Gy γ射线照射5种肿瘤细胞和一种非肿瘤细胞后,观察不同培养时间(24、48、72、96h)内这些细胞B7.1分子的表达水平.用3H-TdR释放试验测定肿瘤细胞和淋巴细胞共反应后细胞毒活性.结果表明,未经照射的肿瘤细胞不表达B7.1分子.经40Gy照射后,SMMC-7721肝癌细胞、PC-12嗜铬神经瘤细胞、A-549肺癌细胞表达B7.1共刺激分子,与对照组相比有非常显著性差异,但SHG胶质瘤细胞和HOS骨肉瘤细胞经60Gy照射后仍未B7.1分子的表达.淋巴细胞与表达B7.1分子的肿瘤细胞共反应后细毒胞活性明显高于未照射组(p<0.01).实验提示,γ射线能诱导人肿瘤细胞表达B7.1分子,增强肿瘤细胞的免疫原性.
展开▼
