甲胎蛋白基因转染树突状细胞瘤苗对诱发性小鼠肝癌发生发展的免疫抑制作用

目的 构建小鼠甲胎蛋白(mAFP)基因转染的树突状细胞(DC)瘤苗,评价其在C57BL/6J小鼠自然肝癌诱发过程中的免疫保护作用.方法 诱导、扩增DC.将表达mAFP的重组腺病毒颗粒转染DC,检测转染前后DC细胞表面分子MHC Ⅰ、MHC Ⅱ、CDl8a(LFA)、CD54(ICAM)、CD80(B7.1)和CD86(B7.2)等的变化.80只C57BL/6J雄性小鼠随机分为单纯接种DC组、接种转mAFP基因DC(pAdBM5-mAFP-DC)组、单纯接种重组质粒(pAdBM5-mAFP)组和正常对照组,每组20只.实验组在每只小鼠的左肋部注射5×105个细胞,连续免疫3 d,以后每7 d接种疫苗1次,继续免疫4次;正常对照组仅注射0.1 ml PBS.在接种免疫的同时,给以二乙基亚硝胺(DEN)、四氯化碳(CCl4)和乙醇联合诱癌.诱癌20周后处死小鼠,检查成瘤情况,并对肝脏标本进行组织病理学检查.结果成功构建了转基因pAdBM5-mAFP-DC瘤苗;mAFP基因转染后的DC表面高表达MHC Ⅰ、MHC Ⅱ、CD18a、CD54、CD80和CD86等共刺激分子,其分子表达率分别为69.3%、41.0%、42.1%、63.2%、39.4%和38.6%,与转染前差异有统计学意义(P＜0.05).单纯接种DC组、pAdBM5-mAFPDC组、pAdBM5.mAFP组和正常对照组的肝癌发生率分别为65.0%、25.0%、70.0%和75.0%,pAdBM5-mAFP-DC组与其他组比较,差异有统计学意义(P＜0.05).结论 pAdBM5-mAFP-DC瘤苗免疫自然诱癌的C57BL/6J小鼠,可降低肝癌的发生率,对肝癌的发生有免疫保护作用.

Dendritic cell vaccine modified by routine mAFP gene enhances immunoprotective effect on liver carcinogenesis and tumor development in mice

Objective To construct a dendritic cell vaccine transduced by murine Mpha-fetoprotein (mAFP)gene,and evaluate its immunoprotective effect on C57BL/6J mice during the induction of hepatoeellular carcinoma by diethylnitrosamines,carbon tetrachloride and ethan01.Methotis Dendritic ceils(DCs)were induced and augmented by murine IL-4 and GM-CSF,and transfected by recombinant adenovirus engineered with mAFP gene.Major MHC class Ⅰ and Ⅱ,B7.1(CD80),B7.2(CD86),CDl8a.and CD54 molecules on DC were analyzed by FACS.80 C57BI/6J male mice were randomly divided into 4 groups(20 mice per group):Simple DC inoculated group,pAdBM5-mAFP-DC inoculated group,pAdBM5-mAFP plasmid inoculated group,and PBS control group.They were immunized once with 5 ×105DCs (0.1 ml)/mouse administered s.c.in the left flank or 100 mg pAdBM5-mAFP plasmid/mouse administered i.m.in the left tibialis anterior muscle.Inoculation was conducted once a week for 4 weeks after 3 times consecutive immunization initially.At the same time of immunization,DEN/CCl4/ethanol were given to induce hepatocellular carcinoma.Tumor incidence was assessed after 20 weeks.Results A transgenic DC vaccine was successfully constructed and the mAFP transgenie DCs expressed high level molecules of major MHC class Ⅰ andⅡ,B7.1,B7.2,CD18a,and CD54.After the 20-week induction,the incidence of primary hepatocellular carcinoma(PLC)was 70.0%in simple DC inoculated group,25.O%in pAdBM5-mAFP-DC inoculated group,65.0%in pAdBM5-mAFP plasmid inoculated group,and 75.0%in PBS control group.There was a significant difference between group B and other groups (P＜0.05).Conclusion mAFP transgenic DC tumor vaccine inoculation may induce strong immunoprotection against liver carcinogenesis and tumor development and reduce PLC incidence induced by DEN/CCl4/ethanol.