粒细胞-巨噬细胞集落刺激因子基因修饰的树突状细胞疫苗增强体外抗肿瘤免疫效应

GM-CSF gene-modified dendritic cell vaccine enhances antitumor immunity in vitro

目的 研究粒细胞-巨噬细胞集落刺激因子（GM-CSF）基因修饰树突状细胞（DC）后形态、表型及功能的变化,以及增强DC疫苗对肿瘤细胞的体外杀伤作用.方法 小鼠尾静脉注射趋化因子配体3（CCL3）,分选得到B220- CDllc＋细胞,经细胞因子培养诱导分化DC.在体外用含GM-CSF基因的重组腺病毒（AdGM-CSF）转染DC,酶联免疫吸附试验（ELJSA）检测转染后GM-CSF的水平.通过细胞形态学观察、表型分析及混合淋巴细胞反应（MLR）,检测GM-CSF基因修饰前后DC的变化.反复冻融法制备胃癌可溶性抗原,将其与GM-CSF基因修饰的DC共同培养,制备DC疫苗,四甲基偶氮唑蓝（MTT）法检测活化的T淋巴细胞在体外对小鼠前胃癌细胞（MFC）的杀伤作用,ELISA法检测干扰素γ（INF-γ）的分泌情况.结果 CCL3注射后,外周血中B220- CD11c＋细胞明显增加,48 h达到高峰[占外周血单个核细胞的（13.88±1.10）%].AdGM-CSF转染后,培养液上清中GM-CSF浓度升高,当感染复数（MOI）为1：100时达到高峰[（130.00±12.61）pg/m1].经GM-CSF.基因修饰的DC在形态上更趋成熟,MHCⅡ类分子、CD80、CD86等细胞表型明显上调,具有更强的刺激T细胞增殖的能力.荷载胃癌抗原的DC激活的T淋巴细胞对MFC细胞具有特异性杀伤作用,并产生高水平的INF-γ[（1245.00±13.75）pg/ml].结论 GM-CSF转染DC后,能大量表达GM-CSF,DC形态及细胞表型更趋成熟,刺激T细胞增殖能力明显增强.GM-CSF基因修饰的DC在体外可诱导出针对靶肿瘤细胞的特异性杀伤作用.

Objective To investigate if granulocyte-macrophage colony stimulating factor （GM-CSF） gene-modified dendritic cells （ DC） enhance antitumor immunity in vitro. Methods Mice were injected with chemokine ligand 3 （CCL3） via the tail vein. Fresh B220-CD11c＋ cells were sorted from the peripheral blood mononuclear cells （PBMCs） and cultured into DCs by cytokines. DCs were transfected with AdGM-CSF gene at different ratios of multiplicity of infection （ MOI） to determine the optimal gene transfection conditions, and the expression of GM-CSF was detected after transfection. The variation of GM-CSF gene-modifiedDCs were analyzed by morphological examination, phenotype analysis, and mixed lymphocyte reaction （MLR）. DCs were loaded with gastric cancer antigen obtained by freezing and thawing method. The killing effect of DCs vaccine-stimulated T lymphocytes on gastric cancer cells was assessed by MTT assay. INF-γ production was determined with the INF-γ ELISA kit. Results B220- CD11c＋ cells increased obviously after CCL3 injection. The ELISA results showed that after GM-CSF gene modification, DCs could produce high level of GM-CSF. When DCs were transfected with AdGM-CSF gene at MOI equal to 100, the GM-CSF level in culture supematants reached saturation [（130.00±12.61） pg/ml]. After GM-CSF gene-modification, DCs tend to be more maturated as detected by morphological observation and phenotype analysis. At the same time, the capacity of activating the proliferation of allogeneic T lymphocytes was enhanced greatly. T lymphocytes stimulated by DCs transfected with GM-CSF gene showed a specific killing effect on gastric carcinoma cells and produced high level of INF-γ[ （ 1245. 00±13. 75） pg/ml].Conclusion After GM-CSF gene modification, DCs can produce high level of GM-CSF, which tend to be more maturated, and the capacity of activating the proliferation of allogeneic T lymphocytes is enhanced greatly. GM-CSF gene modified DCs can induce specific CTL to target tumor cells in vitro.