人4-1BB配体基因真核表达载体的构建、表达及其体外抗肿瘤效应

目的： 构建人4-1BB配体（h4-1BBL）全长基因的真核表达载体, 并在肿瘤细胞HT-29中转染表达; 探讨人4-1BBL基因转染的肿瘤细胞体外诱导的抗肿瘤活性.方法： 用RT-PCR从Raji细胞中克隆h4-1BBL全长基因, 测序后, 构建重组真核表达载体pcDNA3.1（-）-h4-1BBL.通过脂质体法以重组载体转染HT-29细胞, 用RT-PCR检测转染细胞中h4-1BBL mRNA的表达; 用流式细胞术检测转染细胞表面h4-1BBL分子的表达.分离外周血单个核细胞（PBMC）, 用抗CD3 mAb扩增T细胞, 并与h4-1BBL基因转染及未转染的HT-29细胞混合培养.用MTT比色法检测CTL的增殖及杀伤活性; 用流式细胞术检测分泌IFN-γ的T细胞.结果： 从Raji细胞中克隆到h4-1BBL全长cDNA, 测序完全正确.构建的h4-1BBL基因真核表达载体在HT-29中获得稳定表达.与未转染的细胞相比较, h4-1BBL基因转染的肿瘤细胞HT-29能更有效地刺激T细胞活化、增殖, 促进IFN-γ分泌, 并能有效地诱导CTL产生针对野生型HT-29细胞的特异性杀伤.结论： 成功地构建pcDNA3.1（-）h4-1BBL重组真核表达载体.4-1BBL基因转染的肿瘤细胞介导的协同刺激信号, 能增强野生型肿瘤细胞的免疫原性, 诱导T细胞产生有效的抗肿瘤免疫应答.

Construction and expression of eukaryotic expression vector of human 4-1BB ligand gene in tumor cells and its antitumor activity in vitro

AIM: To construct eukaryotic expression vector of human 4-1BB ligand (4-1BBL) gene and express it in HT-29 cell line. To explore the effect on activation and cytotoxicity of human cytotoxic T lymphocytes(CTLs) induced by human 4-1BBL gene transfection into tumor cells in vitro. METHODS: RT-PCR was applied to amplify the full-length of human 4-1BBL gene from Raji cells. After sequencing, the cDNA was recombinated into the eukaryotic expression vector pcDNA3.1(-) and transfected into HT-29 cells through Lipofect AMINE 2000. Human 4-1BBL mRNA and protein expression of transfected cells was detected by RT-PCR and FACS respectively. Human peripheral blood mononuclear cells were stimulated with anti-CD3 mAb and incubated with non-transfected or transfected HT-29 cells, respectively. The MTT colorimetry was used to detect the proliferation and cytotoxic effect of T lymphocytes. Meanwhile, the expression of intracellular IFN-gamma was detected by FCM. RESULTS: The HT-29 cells transfected by pcDNA3.1(-)-h4-1BBL could express human 4-1BBL efficiently. As compared with wild type HT-29 cells, the transfected HT-29 cells had more effect for proliferation, IFN-gamma production and cytotoxic activity of lymphocytes. CONCLUSION: The recombinant eukaryotic expression vector of pcDNA3.1(-)-h4-1BBL is successfully constructed. The transfection of human 4-1BBL gene in HT-29 cells is effctive in enhancing its immunogenicity and inducing antitumor immune response in vitro.