基于SOE-PCR的核酸疫苗pIRES2-MLAA34-HSP70的构建及免疫效果研究

目的 构建pIRES2-MLAA34-HSP70重组质粒,并检测其免疫效果.方法 采用逆转录PCR(RT-PCR)的方法提取急性单核细胞白血病相关抗原基因MLAA-34和热休克蛋白(HSP) 70基因,设计特异性重叠引物,以重叠延伸PCR(SOE-PCR)技术扩增MLAA34-HSP70融合基因,构建核酸疫苗pIRES2-MLAA34-HSP70.将核酸疫苗免疫BALB/c小鼠,检测小鼠脾淋巴细胞对U937细胞的杀伤作用及小鼠脾细胞悬液中白细胞介素(IL)-2、IL-4和γ干扰素(IFN-γ)水平.结果 扩增出MLAA34-HSP70融合基因2 956 bp,成功构建了核酸疫苗pIRES2-MLAA34-HSP70,经鉴定与预期结果一致;脾淋巴细胞杀伤活性结果显示,核酸疫苗pIRES2-MLAA34-HSP70对U937细胞的杀伤效率明显高于其他实验组及对照组(P＜0.01);核酸疫苗pIRES2-MLAA34-HSP70组细胞因子IL-2、IL-4和IFN-γ水平亦明显高于其他实验组及对照组(P＜0.01).结论 成功构建了pIRES2-MLAA34-HSP70核酸疫苗,该核酸疫苗能诱发强烈的体液免疫,增强机体对肿瘤细胞的免疫应答,对MLAA34阳性细胞具有特异性杀伤作用.

Study on immune effect of DNA vaccine pIRES2-MLAA34-HSP70 constructed by SOE-PCR

Objective To construct the DNA vaccine pIRES2-MLAA34-HSP70,and to detect its immune effect.Methods The acute monocytic leukemia associated antigen gene MLAA-34 and heat-shock protein (HSP)70 gene were extracted by using RT-PCR.The specific overlapping primer was designed,and the fusion gene MLAA34-HSP70 was amplified by using SOE-PCR technique.Then the DNA vaccine pIRES2-MLAA34-HSP70 was constructed,and BALB/c mice were immunized with this DNA vaccine.The splenic lymphocyte killing activity was detected by using MTT,levels of IL-2,IL-4 and IFN-γ were also detected by using ELISA.Results The MLAA34-HSP70 gene (2 956 bp) and the DNA vaccine pIRES2-MLAA34-HSP70 was amplified and constructed successfully.The killing efficiency of DNA vaccine pIRES2-MLAA34-HSP70 in U937 cells was significantly higher than that in other experimental groups and control group (P＜0.01),and levels of IL-4,IL-2 and IFN-γin DNA vaccine pIRES2-MLAA34-HSP70 group were significantly higher than those in the other experimental groups and control group (P＜0.01).Conclnsion The DNA vaccine pIRES2-MLAA34-HSP70 is constructed successfully.It is shown that the DNA vaccine induces strong humoral immunity,which could enhance immune responses to tumor cells and specificlly kill MLAA34 positive cells.