微囊化小鼠白介素12基因工程细胞的长效抗肿瘤作用

目的　探讨通过微囊化能否获取长效抗肿瘤的小鼠白介素 12 (mIL 12 )基因工程细胞。方法　构建pcDNA3.1/mIL 12重组表达质粒 ,然后稳定转染CHO细胞 ,采用海藻酸钠微囊制作技术 ,将mIL 12基因修饰的CHO细胞包裹。观察微囊化mIL 12基因工程细胞的mIL 12释放 ,并将微囊化细胞植入荷瘤小鼠体内 ,测定小鼠的抗肿瘤免疫功能及抑瘤效应。结果　微囊化mIL 12基因工程细胞产生的mIL 12蛋白可自由透过微囊膜。植入荷瘤小鼠体内2 1d后 ,微囊化mIL 12基因工程细胞治疗组血清中mIL 12 ,mIL 2及mIFN γ水平分别为 (5 49± 5 3) ,(180± 2 9)和 (10 0 8± 15 6 )ng·L- 1,而mIL 4 ,mIL 10水平则显著降低。脾脏细胞毒T淋巴细胞 (CTL)活性及自然杀伤细胞 (NK)活性均显著增高 ,肿瘤生长受到显著性抑制 ,荷瘤小鼠的存活期明显延长。结论微囊化mIL 12基因工程细胞在体内可持续、稳定地释放mIL 12 ,能激发机体产生持久而强大的抗肿瘤免疫反应 ,对实验小鼠产生明显的抗肿瘤效应并延长其生存期。

Long-term anti-tumor effects of microencapsulated murine interleukins-12 engineered cells

AIM To investigate if long-term antitumoric murine interleukin-12(mIL-12) gene- engineering cells could be obtained by microencapsulation. METHODS Reconstructed plasmid pcDNA3.1/mIL-12 was transfected into CHO cells stably by Superfect^TM, then CHO/pcDNA3.1/mIL-12 cells were encapsulated in alginate microcapsules. mIL- 12 release from the microencapsulated CHO/pcDNA3.1/mIL- 12 cells was confirmed using ELISA assay. Microencapsulated CHO/pcDNA3.1/mIL-12 cells were transplanted subcutaneously into the tumor-bearing mice with CT26 cells. The anti- tumor immunoreaction responses and the anti-tumor activities of the microencapsulated CHO/pcDNA3.1/mIL- 12 cells were evaluated. RESULTS mIL- 12 protein could release freely from the microencapsulated CHO/pcDNA3.1/mIL-12 cells. After the microencapsulated CHO/pcDNA3.1/mIL- 12 cells were transplanted subcutaneously into the tumor- bearing mice for 21 d, the serum average concentrations of mIL-12, mIL- 2 and mIFN-γ in the mice treated with microencapsulated CHO/pcDNA3.1/mIL- 12 cells were（549±53）, （180±29）and （1008±156）ng·L^-1，respectively, but the serum concentrations of mIL-4 and mIL- 10 were decreased significantly compared to the controls. The cytotoxicity of the CTL from the splenocytes and the NK activity were significantly higher in the mice treated with microencapsulated CHO/pcDNA3.1/mIL-12 cells. Moreover, mIL- 12 released from the microencapsulated CHO/pcDNA3.1/mIL-12 cells continuously and stably brought a significantly inhibition of tumor proliferation and a prolonged survival time of tumor-bearing mice. CONCLUSION The results showed that microencapsulated CHO/pcDNA3.1/mIL- 12 cells expressed significant antitumor effects in the experimental tumor- bearing mice by activating anti-tumor immune responses in vivo.