树突状细胞靶向性DNA疫苗的抗肿瘤免疫效应

Immunological efficiency of DNA vaccine targeting dendritic cells against tumor

目的:构建含OVA-Fc融合基因并对树突状细胞具有靶向性的DNA疫苗,评价其在肿瘤治疗中的作用。方法:构建真核表达载体OVA-Fc-pcDNA3.1,以脂质体转染法将其导入CHO细胞,用流式细胞术和ELISA法检测融合蛋白OVA-Fc的表达。建立E.G7-OVA荷瘤小鼠模型,用51Cr释放实验测定免疫小鼠脾脏细胞毒性T淋巴细胞(CTL)的抗肿瘤活性。通过观察荷瘤小鼠肿瘤的体积和生存期评价该肿瘤疫苗的疗效。结果:酶切鉴定和序列测定证明,真核表达载体OVA-Fc-pcDNA3.1构建正确。用流式细胞术和ELISA法均表明,转染的CHO细胞能表达OVA-Fc融合蛋白。OVA-Fc能激发CTL的杀伤活性,发挥抗肿瘤作用,从而减缓肿瘤的生长,延长荷瘤小鼠的生存期。结论:含OVA-Fc-pcDNA3.1的树突状细胞靶向性DNA疫苗能在体内有效地激发抗瘤免疫应答,为进一步开展临床实验奠定了基础。

AIM： To construct the DNA vaccine containing ovalbumin （OVA） and Fc fusion gene targeting dentritic cells （DCs） and evaluate its anti-tumor efficiency in an E. G7-OVA-bearing tumor model. METHODS - Constructed OVA-Fc-pcDNA3.1 plasmids were transfected into CHO cells with lipofectamine and the in vitro expression of OVAFc was determined by flow cytometry and ELISA. ^51 Cr-relaese assay was used to determine the anti-tumor activity of cytotoxic T lymphocytes （CTLs） from splenocytes of immunized mice. According to tumor volume and survival time of the mice, the therapeutic effect of this vaccine was evaluated in E. GT-OVA-bearing tumor model. RESULTS： DNA sequencing and restriction endonuclease digestion analysis indicated that the recombinant expression vector OVA-FcpcDNA3. I had been constructed successfully. OVA-Fc expression could be detected in CHO cells transfected with OVA-Fc-pcDNA3. I by ELISA and flow cytometry. The DNA vaccine containing OVA-Fc fusion gene inhibited tumor＇s growth and prolonged the time of tumor-bearing mice due to elicit the CTL-mediated anti-tumor immunity. CONCLUSION： OVA-Fc-pcDNA3. I DNA vaccine targeting dendritic cells can elicit the CTL-mediated anti-tumor immunity, which lays the foundation for further clinical experiments.