摘要目的 探讨转染小鼠带有信号肽的AFP_1 cDNA和去掉信号肽的AFP_2 cDNA树突状细胞(DC)在体外的免疫活性,以及其对Balb/c小鼠皮下移植瘤的抑制作用.方法 应用磷酸钙纳米颗粒将带有信号肽的AFP_1 cDNA和去掉信号肽的AFP_2 cDNA 真核表达载体pcDNA3.1转染DC,将DC疫苗与同源小鼠脾淋巴细胞混合培养,采用酶联免疫吸附(ELISA)法,检测上清液中干扰素γ(IFN-γ)的表达情况.采用四甲基偶氮唑蓝(MTT)法,检测AFP_1/DC和AFP_2/DC刺激同基因小鼠脾淋巴细胞增殖能力及诱导特异性细胞毒性T淋巴细胞(CTL)的杀伤能力.观察AFP_1/DC和AFP_2/DC对Balb/c小鼠皮下移植瘤生长的抑制作用.结果 AFP_2/DC能明显促进脾淋巴细胞增殖并提高CTL的特异性杀伤作用.AFP_1/DC和AFP_2/DC瘤内注射均可显著抑制肝癌移植瘤的生长,但AFP_2/DC的抑制作用更明显,治疗2周后,AFP_2/DC组小鼠肿瘤体积为(726.7±298.2)mm3,明显小于AFP_1/DC组[(1486.2±457.2)mm~3]和空质粒对照组[(2137.2±547.2)mm~3,P<0.05].AFP_2/DC组和AFP_1/DC组的抑瘤率分别达79.2%和39.7%,而空质粒对照组和空白对照组的抑瘤率为0.AFP_2/DC组和AFP_1/DC 组小鼠的生存时间分别为(58.5±4.2)d和(45.2±4.8)d,较空质粒对照组[(30.6±6.2)d]显著延长(P<0.05).结论 AFP_2/DC 疫苗在体外能够诱导出高效而特异的抗肿瘤免疫效应,在体内具有抑制Balb/c小鼠皮下移植瘤生长的作用.

abstractsObjective To investigate the antitumor immune response induced by dendritic cells vaccine coding AFPcDNA fragment with signal peptide (AFP_1) and without signal peptide ( AFP_2), and to determine the inhibiting effect of the vaccine on the growth of bepatocarcinoma xenograft in Balb/c mice. Methods pcDNA3.1/AFP_1 and pcDNA3.1/AFP_2 were transfected into dendritic cells(DCs) by calcium phosphate nanoparticles and became DCs vaccine. Mouse spleen lymphoeytes were stimulated by AFP_1/DC and AFP_2/DC. A Balb/c mouse model bearing mouse HCC xenograft was established on the day 14 after transplantation. Forty mice were divided equally into AFP_2DC group, AFP_1/DC group and plasmid control group. The treated mice received DCs vaccine and the same amount of control plasmid. Results AFP_2/DC stimulated T lymphocytel proliferation in vitro and improved CTL activity. The effects were better than AFP_1/DC. The tumor-bearing mice injected intralesionally with AFP_1/DC and AFP_2/DC at a dose of 0.5 ml per mouse showed inhibition of tumor growth and prolongation of survival time. The tumor inhibition rate of the AFP_2/DC group was 79.2% and the AFP_1/DC group was 39.7% at 2 weeks after treatment. The tumor volume of AFP_2/DC group was (726.7±298.2) mm~3, significantly smaller than the (1486.2±457.2) mm~3 of the AFP_1/DC group and ( 2137.2±547.2 ) mm~3 of the plasmid control group ( P < 0.05 ). The mean survival time of mice in the AFP_2/DC group [ (58.5±4.2) d] and AFP_1/DC group [ ( 45.2±4.8 ) d ] were significantly longer than that of plasmid control group [ ( 30.6±6.2 ) d, P < 0. 05 ]. Bax-positive cell percentage was increased in the xenografts of AFP_2/DC-treatment group compare with that of plasmid control group. Conclusion AFP_2/DC and AFP_1/DC vaccines show evident inhibiting effect on the growth of H22 xenograft in Balb/c mice through inducing efficient and specific immune response against the hepatocarcinoma cells.