负载EB病毒潜伏膜蛋白基因的树突状细胞疫苗的体内抗肿瘤免疫作用

Antitumor immune effect induced by dendritic cell transfected with EBV-LMP2 gene in mice

目的观察负载EB病毒潜伏膜蛋白(EBV-LMP2)基因的树突状细胞(DC)疫苗体内激活的细胞毒T细胞(CTLs),在严重联合免疫缺陷(SCID)小鼠体内对人鼻咽癌(NPC)细胞株CNE-2的免疫保护作用。方法人外周血来源的单核细胞(PBMC)经细胞因子扩增培养为成熟DC,rAd-EBV-LMP2重组腺病毒转染DC制备疫苗,对疫苗进行致瘤性检测;采用人外周血T细胞悬液腹腔注射建立人外周血淋巴细胞-严重联合免疫缺陷小鼠(hu-PBL-SCID)模型,随机分为4组:对照组、T细胞组、未转染DC组、LMP2-DC组。末次免疫7d后,接种CNE-2细胞,观察小鼠成瘤率、成瘤潜伏期、肿瘤体积及重量;定期检测小鼠血清中人IgG水平;测定小鼠脾淋巴细胞的特异性细胞毒淋巴细胞(CTL)活性。结果 rAd-EBV-LMP2-DC疫苗接种于小鼠体内未见肿瘤形成,脾、肺、肝和肾等器官未出现肿瘤病变;小鼠血清均检测出人IgG,hu-PBL-SCID嵌合模型重建成功;LMP2-DC组肿瘤的潜伏期明显延长,肿瘤生长速度、体积及重量显著减小(P<0.01),且LMP2-DC组小鼠脾淋巴细胞显示出对肿瘤细胞强大的杀伤活性(P<0.01)。结论 EBV-LMP2-DC疫苗能在hu-PBL-SCID小鼠体内诱导产生强大的CTL反应,保护小鼠免受肿瘤细胞的攻击,对肿瘤细胞具有有效的免疫保护作用。

Objective To study the immunopreventive effects of CTLs actived by dendritic cells（DCs）-based cancer vaccine（EBV-LMP2-DC） on CNE-2 cells in SCID mice. Methods DC-enriched populations derived from hu-man peripheral blood mononuclear cells （PBMC） were induced by cytokines, and then the EBV-LMP2 recombinant adenovirus were transfected into DCs to prepare the vaccine. Tumorigenicity of the vaccines were detected. The SCID mice were intraperitoneal injected with human peripheral blood lymphocytes （PBLs） for immune reconstruction. The mice were randomly divided into 4 groups： control group; T lymphocyte group; utransfected DC group and LMP2-DC group. Seven days after the last immunization, each group of mice subcutaneously implanted CNE-2 cells. The gener-ating rate of transplanted tumor, tumor latency and tumor size were detected. Human IgG in mouse serum were tested periodically and the specific CTL activity of mouse spleen lymphocytes were determined. Results No tumor was found inspleen, lung, liver and kidney after the EBV-LMP2-DC vaccine injection. The hum-PBL-SCID models were established successfully with human IgG in mouse serum detected out. The tumor latent period of LMP2-DC group were increased and the tumor generating rate, the volume and the weight of tumor were decreased （P〈0.01）. The spe- cific cytotoxieity against tumor cells of the mouse spleen lymphocytes in LMP2-DC group was significantly higher than that in controls（P〈0.01）. Conclusion The EBV-LMP2-DC vaccine could elicit strong CTL response in hu-PBL-SCID mice and could protect mice from attack by tumor cells, which indicates its potent immuno-preventive effects on tu-mor.