树突状细胞融合瘤苗体内外诱导特异性抗白血病免疫的实验研究

本研究观察615鼠骨髓来源树突状细胞(DC)与白血病细胞L615融合瘤苗L615/DC体内外诱导特异性抗白血病免疫的能力。分别制备615鼠骨髓来源DC,用PEG融合法将DC与照射灭活的L615制备L615/DC融合瘤苗并免疫动物,用MTT法和LDH法测定L615/DC融合瘤苗免疫鼠脾细胞体外MLR反应和对L615特异性杀伤活性,同时通过免疫治疗实验检测L615/DC融合瘤苗的体内抗白血病作用。结果表明:研究获得了具有特征形态的树突状细胞,MLR反应表现出强大的异基因免疫刺激功能,当L615/DC融合瘤苗免疫鼠的脾细胞再次接触L615抗原时表现出强烈的增殖活性;LDH实验显示,融合瘤苗组、共培瘤苗组和灭活L615组均可在体外诱导扩增出L615特异性CTL,但融合瘤苗组的CTL在不同效靶比、不同孵育时间的特异性杀伤活性均明显高于另两组(P<0.01)。体内免疫治疗实验中L615/DC融合瘤苗治疗组平均寿命为25.7±1天,有1/4小鼠长期存活,而对照组全部死亡,平均寿命17.5±1天。2个月后对治疗组存活鼠用致死剂量L615攻击不发病。结论:L615/DC融合瘤苗可诱导强大的特异性抗L615免疫,它不仅在体外能特异性识别并杀伤L615细胞,还可有效抑制荷瘤鼠体内肿瘤的生长,延长存活时间,并产生免疫记忆,抵抗肿瘤的二次攻击。L615/DC融合瘤苗为肿瘤免疫治疗提供了新的手段。

Anti-leukemia Immunity Induced by Dendritic Cells Fused with L615 Tumor Cells

This study was aimed to investigate the specific anti-L615 leukemia cell immunity induced by L615/DC fused cell vaccine in vivo and in vitro. BM-derived DCs were generated from bone marrow of 615 mice by culturing for 9 - 10 days in culture medium supplemented with GM-CSF and IL-4. Irradiated L615 tumor cells were fused with DC by using PEG to form fused cell vaccine, with which 615 mice were immunized. After immunization, the specific proliferation ability and cytotoxicity against L615 leukemia cells in vitro were examined by MTT and LDH methods. Anti-leukemia effect of fused cell vaccine in vivo was studied by observing the immunotherapy effects on L615 tumor-bearing mice. The results showed that fully mature and functional bone marrow-derived DC were obtained. L615/DC fused cell vaccine could elicit potent specific proliferation response of spleen T cells from immunized mice when contacting with the same antigen at the second time, and could also elicit the effective cytotoxic activity against L615 leukemia cells in vitro, which were significantly different from other groups. In vivo the average survival time of the tumor-bearing mice received immunotherapy with L615/DC fused cell vaccine was 25.7 +/- 1 days, and one fourth of treated tumor-bearing mice survived for long time, but the mice of control group died all, their average of survival time was 17.5 +/- 1 days. The immunized mice survived with no evidence of recurrence when exposed to the second attack of lethal dose of living L615 cells 2 months later. It is concluded that L615/DC fused cell vaccine can improve the immunogenecity of L615 and induce effectively the specific anti-leukemia immunity against L615 leukemia cells to eliminate the residual leukemia cells, prolong the survival time and induce the immune memory to avoid the relapse. Thus, the fused cell vaccine may be an attractive strategy for malignance immunotherapy.