卡介苗HSP70基因转染对小鼠淋巴细胞白血病细胞免疫原性的影响

BCG HSP70 gene transfection and its effect on immunogenicity of murine lymphocytic leukemia

目的探讨卡介苗热休克蛋白70(BCG HSP70)基因转染对小鼠淋巴细胞白血病细胞(L1210)致瘤性及免疫原性的影响。方法利用脂质体2000将BCG HSP70基因转入小鼠淋巴细胞白血病细胞系L1210表面,获得高表达HSP70分子的L1210-HSP70细胞,作为肿瘤疫苗分别对裸鼠及同系小鼠致瘤性、瘤苗对荷瘤小鼠的免疫治疗作用以及瘤苗对L1210细胞攻击的免疫保护作用进行研究。结果 BCG HSP70成功表达在转染后的L1210细胞表面,并具有与野生型细胞同样的致瘤性。同系小鼠DBA/2皮下接种L1210-HSP70细胞后肿瘤生长缓慢或不成瘤;相对于L1210组和L1210-neo组,生存期明显延长,小鼠脾淋巴细胞中针对L1210细胞的特异性T细胞数量明显增加,差异有统计学意义(P<0.05);瘤体病理切片示彻底凝固性坏死,周边可见淋巴样细胞,免疫组化检测示大量CD8+T淋巴细胞浸润。L1210-HSP70细胞瘤苗具有对荷瘤小鼠的免疫治疗作用,以及抗肿瘤攻击的免疫保护作用,均表现为肿瘤出瘤时间明显延长,生长受到显著抑制,瘤体平均直径明显减小;荷瘤小鼠生存时间明显长于L1210组、L1210-neo组和PBS组,差异有统计学意义(P<0.05)。结论BCG HSP70基因转染能有效增强肿瘤细胞的免疫原性,激活特异性T细胞,降低肿瘤细胞的致瘤性;并具有提高宿主抗瘤免疫作用。

Objective To assess the effect of heat shock protein 70 of BCG（BCG HSP70） gene transfection on tumorigenicity and immunogenicity of murine lymphocytic leukemia cells（L1210）. Methods BCG HSP70 gene was transfected onto the surface of murine lymphocytic leukemia cells（L1210） by lipofectamine 2000. And then the positive clone（L1210-HSP70） highly expressing HSP70 was selected as the tumor vaccine to study the tumorigenicity experiments in nude mice and syngeneic mice, the therapeutic experiments, and the immunoprotective effects. Results The expression of BCG HSP70 on the L1210 cells surface was detected, and the L1210-HSP70 cells had the same tumorigenicity as the parental L1210 cells did. Tumorigenicity experiments in syngeneic mice： In L1210-HSP70 group, tumor growth was slow or without the formation of tumor. As compared with L1210 group and L1210-neo group the mice survival time was significantly prolonged, showing a marked stimulating effect on L1210 specific Th1 cells,. Tumor-bearing mice showed complete coagulation necrosis and abundant CD8^＋ T lymphocyte infiltration（P〈0.05）. The tumor vaccine of L1210-HSP70 cells had the antitumor therapeutic efficacy and immune protection effect, demonstrating that the tumor growth was significantly inhibited, tumor diameter was markedly reduced and the survival time of tumor-bearing DBA/2 mice was further prolonged. Conclusions BCG HSP70 gene transfection could effectively improve the immunogenicity of tumor cells, activate specific T cells and enhance the anti-tumor immunity in vivo. Meanwhile, the host anti-tumor immunity could be enhanced.