胃癌MG7-Ag模拟表位与HSP70融合基因疫苗的构建及其诱导小鼠免疫反应的研究  

Study on immune response induced by the fusion gene vaccine of gastric cancer MG7-Ag mimotope and heat shock protein 70 in mice

作　　者：宁晓暄[1] 吴开春[1] 李源[1] 时永全[1] 徐立[1] 乔太东[1] 陈宝军[1] 樊代明[1] 

机构地区：[1]第四军医大学西京医院,西安710032

出　　处：《解放军医学杂志》2004年第3期240-242,共3页Medical Journal of Chinese People's Liberation Army

基　　金：国家高技术研究发展计划 (863计划 ) (编号 2 0 0 1AA2 1 542 1 );国家自然科学基金 (编号 39870 742 )资助课题

摘　　要：目的　以热休克蛋白 70 (HSP70 )为载体 ,构建胃癌MG7 Ag模拟表位与HSP70融合基因的DNA疫苗 ,并观察该疫苗诱导C5 7BL/ 6小鼠产生MG7 Ag特异性免疫反应的作用。方法　将胃癌MG7 Ag模拟表位 (九肽 )的编码序列设计在HSP70下游引物的 5′末端 ,通过PCR方法获得HSP70与模拟表位的融合基因片段。将PCR产物克隆入真核表达载体pcDNA3.1(+) ,构建融合基因疫苗。将该融合基因疫苗接种C5 7BL/ 6小鼠股四头肌 ,每隔 3周加强免疫一次 ,共接种 3次。分别在每次接种后 3周收集免疫血清 ,用细胞ELISA法检测小鼠血清中抗MG7 Ag抗体的水平。末次免疫后 3周 ,收集脾细胞 ,用51Cr释放法检测MG7 Ag特异性CTL的杀伤活性。结果　PCR扩增得到大小约 2 .0kb的片段 ,与预期大小一致。将该片段克隆入pcDNA3.1(+) ,DNA序列测定证实MG7 Ag模拟表位的编码序列已成功融合于HSP70cDNA的 3′末端。基因疫苗免疫后 ,融合基因免疫组小鼠于第 9周出现抗MG7 Ag抗体 ,而对照组小鼠无MG7 Ag抗体产生 (P <0 0 5 )。51Cr释放实验结果表明 ,融合基因免疫组小鼠脾细胞对靶细胞的杀伤率与对照组相比无显著差异 (P >0 0 5 )。结论　MG7 Ag模拟表位与HSP70融合基因疫苗构建成功 ;该融合基因疫苗能够诱导MG7Objective To construct a fusion gene vaccine of gastric cancer MG7-Ag mimotope and heat shock protein 70, and to investigate the humoral and cellular immune response in mice induced by the vaccine. Methods The coding sequence of MG7 mimotope was incorporated with HSP70 gene at the 3' terminus by PCR amplification. Then the PCR product was cloned into pcDNA3.1(+) vector to construct the eukaryotic expression vector. The pcDNA3.1/MG7+hsp70 was sequenced to ensure the proper encoding. C57BL/6 mice were immunized with the fusion gene vaccine, and pcDNA3.1/hsp70 and empty pcDNA3.1 were used as controls. The serum was collected at the 3rd week after each immunization. Cellular ELISA was performed to evaluate the induced humoral immunity. The splenocytes were first separated at the 9th week for the assay of antigen specific CTL lysis activity by 51Cr release. Results A fragment about 2.0 kb was obtained by PCR amplification. Sequence analysis revealed that the sequence of mimotope was connected successfully to 3' terminus of hsp70 and the fusion gene was cloned into the pcDNA3.1(+) successfully. Cellular ELISA results suggested that the serum level of MG7-Ag antibody appeared in the vaccinated mice at 9th week, while no MG7-Ag antibody was detected in the controls. The results of the specific lysis rate of splenocytes showed no statistical difference between fusion gene vaccine group and control groups. Conclusion The fusion gene vaccine was constructed successfully and the specific humoral immune response was induced by the fusion gene vaccine.

关 键 词：胃肿瘤 疫苗 基因 热休克蛋白质类70 分子模拟 

分 类 号：R73-362[医药卫生—肿瘤]