摘要
目的 利用减毒鼠伤寒沙门氏菌研制胃癌MG7 Ag模拟表位的口服DNA疫苗 ,并观察其对小鼠的免疫效能及保护作用。方法 构建MG7 Ag模拟表位和通用性辅助性T细胞表位融合基因的真核表达载体。将真核表达载体转入减毒鼠伤寒沙门氏菌得到模拟表位的口服DNA疫苗。以 1× 10 8cfu疫苗菌口服免疫C5 7BL/6J小鼠 ,以携带空载体的沙门氏菌和PBS口服作为对照。以ELISA法检测小鼠血清中抗MG7 Ag抗体的滴度 ,以H TDR掺入法检测小鼠脾淋巴细胞对人工合成的MG7 Ag抗原肽刺激的增殖能力。同时 ,用表达MG7 Ag的小鼠艾氏腹水瘤细胞进行肿瘤攻击 ,观察疫苗对小鼠的保护作用。结果 口服疫苗可诱导小鼠产生MG7抗体 ,但各组小鼠脾淋巴细胞体外刺激增殖实验差异无显著性。肿瘤攻击 2周后 ,疫苗免疫组 7只小鼠中有 2只未见肿瘤形成 ,而对照组 4只小鼠则全部成瘤。结论 胃癌MG7 Ag模拟表位的口服DNA疫苗具有免疫原性 ,可以诱导小鼠产生抗肿瘤免疫 。
Objective To develop an oral DNA vaccine based on MG 7 Ag mimotope of gastric cancer using attenuated Salmonella typhimurium and evaluate its efficacy and protective effect. Methods The eukaryotic expression vector including the MG 7 Ag mimotope and a Th epitope was constructed, and then transduced into an attenuated Salmonella typhimurium to get the oral DNA vaccine. C57BL/6 J mice were orally immunized with 1×10 8 cfu Salmonella transfectants, with Salmonella harboring empty plasmid, with phophate buffered saline (PBS) as control. At the 6th week, serum titer of MG 7 antibody was detected by ELISA. In the 8 th week, a thymidine incorporation assay was performed to test the proliferation of murine spleen cells to the stimulant of MG 7 Ag mimicry peptide. At the same time, Ehrlich ascites carcinoma cells expressing MG 7 Ag were used in tumor challenge assay to evaluate the protective effect of the immunization. Results The oral DNA vaccine induced MG 7 antibody in mice, while in vivo unprimed proliferation assay of the spleenocytes showed no difference among the three groups. Two weeks after tumor challenge, 2 in 7 immunized mice were tumor free, while none in the control group was protected.Conclusion Oral DNA vaccine based on the MG 7 Ag momitope is immunogenic. It is able to induce specific immunity response against tumor in mice, and the vaccine is partially protective. [
出处
《中华肿瘤杂志》
CAS
CSCD
北大核心
2002年第2期110-113,共4页
Chinese Journal of Oncology
基金
国家自然科学基金资助项目 (3 9870 7423 980 0 0 5 7)
