小鼠白细胞介素21瘤苗的构建及其抗肿瘤效应研究

目的:建立稳定表达小鼠白细胞介素21(mIL-21)的肿瘤细胞瘤苗,观察其在小鼠体内是否能够诱导有效的抗肿瘤免疫反应及免疫记忆效应。方法:将已鉴定的重组质粒pcDNA3.1/mIL-21用脂质体法转染Sp2/0细胞制备瘤苗,RT-PCR法鉴定瘤苗中mIL-21的表达。通过流式细胞仪检测细胞周期来反映瘤苗体外增殖活性,再将其接种BALB/c小鼠,监测肿瘤生长情况,观察mIL-21瘤苗诱导的抗肿瘤效应;用ELISA法检测血清IFN-γ和IL-4含量。结果:得到稳定表达mIL-21的瘤苗Sp2/0-mIL-21。与对照组相比,体外增殖活性无差异。皮下接种BALB/c小鼠后,肿瘤生长缓慢,部分小鼠无瘤体生长并长期存活;用野生株Sp2/0瘤细胞再次攻击未长肿瘤的实验小鼠,4周后亦未见肿瘤生长。接种瘤苗小鼠血清中IFN-γ水平明显上升,IL-4无明显增高。结论:成功构建了mIL-21瘤苗Sp2/0-mIL-21,其能诱导有效的抗肿瘤免疫反应及免疫记忆效应。

Construction and its Antitumor Efficiency of Murine Interleukin 21 Tunor Vaccine

Objective: To construct the tumor vaccine expressing murine interleukin 21(mIL-21) stably and evaluate its anti-tumor effects in mice. Methods: The identified recombinant plasmid pcDNA3.1/mIL-21 was transfected into Sp2/0 cells via LipofectAMINE. The expression of mIL-21 was detected by RT-PCR. The proliferation activity of tumor cells reflected the cell cycle in vitro were respectively detected by flow cytometry. The anti-tumor effects were evaluated from surveying the tumor growth state after the tumor vaccine was inoculated into s.c BALB/c mice. Results: The Sp2/0-mIL-21 tumor vaccine expressing mIL-21 was successfully constructed. The tumors developed slowly in BALB/c mice injected with tumor vaccine, compared with the control mice injected with Sp2/0 and Sp2/0-pcDNA cells. Some of those mice even lived for a long time without tumors. The mice without tumor were rechallenged with Sp2/0 cells. After 4 weeks, there was only one mice from four mice growth a small tumor in challenged mice. The level of IFN-g was higher in mice inoculated with tumor vaccine than that of control mice, but no difference was found in the levels of IL-4 between the mice inoculated with tumor vaccine and the control mice. Conclusion: The mIL-21 tumor vaccine is successfully constructed and it has a higher immunogenicity and lower tumorigenesis than those the Sp2/0 cells. The mIL-21 tumor vaccine can also induce immune memory response to tumor cells.