摘要 目的：研究B7基因修饰的肿瘤细胞诱导抗大肠癌CTL的活化。方法：采用电击法将B7基因导入小鼠大肠癌细胞CMT93，G418筛选阳性克隆，免疫组化显示B7分子有高效表达，B7⁺ CMT93(CMT93-B7)接种于C57BL/6小鼠背部皮下，其致瘤性显著下降(P<0.01)；CMT93-B7致敏的小鼠对野生型瘤细胞具有免疫保护作用(P<0.05)；用CMT93和CMT93-B7细胞分别经腹腔免疫小鼠，得到腹腔浸润淋巴细胞及致敏脾细胞，MTT法进行体外杀伤实验。结果：CMT93-B7诱导的CTL(cytotoxicTlymphocyte)对CMT93的杀伤活性显著高于野生型CMT93诱导的CTL对相同靶细胞的杀伤活性(P<0.05)，并且CMT93-B7诱导的CTL对CMT93-B7的杀伤率显著高于对野生型CMT93的杀伤率(P<0.05)。结论：B7分子有效地促进抗大肠癌CTL的活化，在CTL的效应阶段B7分子也发挥重要作用。

Anti - colonic Cancer Active Immunity Induced by B7 Gene Modified Tumor Cells

Hu Jinyue Wang Sa Zhu Jiangao et al
(Cancer Research Institute, Hunan Medical University, Changsha)

Abstract Objective : To study the activation of CTLs against colorectal cancer cells induced by B7 gene modified tumor cells.Methods : B7 gene was transfected into mouse colorectal cancer CMT93 cells. The positive clones were selected by G418..The immunohistochemistry showed that B7 molecules were highly expressed. The B7 + CMT93 (CMT93 - B7) cells were inoculated into the back of C57B1/6 mice subcutaneously and then it decreased their tumorigenicity greatly (P< 0.01). The CMT93 - B7 cell sensitized mice obtained the protective immune activity against the rechanllenge of wild type CMT93 cells (P< 0.05). The abdominal infiltrating lymphocytes and sensitizing spleen cells were obtained from the mice who were immunized with CMT93 - B7 or wild type CMT93 cells intraperitoneally., and the cytotoxicity of these CTLs against tumor cells was detected by MTT assay. Results : It showed that the cytotoxicity of CTL induced by CMT93 - B7 against CMT93 was significantly higher than the cytotoxicity of CTL induced by wild CMT93 against the same target cells (P< 0.05). Conclusion : The results suggest that the B7 molecules can effectively promote the activity of CTL against colorectal cancer
cells, and B7 molecules play an important role in CTL cytotoxicity function as well.
Key Words Colorectal cancer Immunology Therapy B7 gene Gene transfer

T细胞活化需要两个信号的作用^[1] ......