AIM: To develop an oral DNA vaccine against gastric cancer and evaluate its efficacy in mice.METHODS: The genes of the MG7-Ag mimotope and a universal Th epitope (Pan-DR epitope, PADRE) were included in the PCR primer...AIM: To develop an oral DNA vaccine against gastric cancer and evaluate its efficacy in mice.METHODS: The genes of the MG7-Ag mimotope and a universal Th epitope (Pan-DR epitope, PADRE) were included in the PCR primers. By PCR, the fusion gene of the two epitopes was amplified. The fusion gene was confirmed by sequencing and was then cloned into pcDNA3.1(+) plasmid. The pcDNA3.1 (+)-MG7/PADRE was used to transfect an attenuated Salrmonella typhimuriurm.C57BL/6 mice were orally immunized with 1x108 cfu Salrmonella transfectants. Salmonella harboring the empty pcDNA3.1(+) plasmid and phosphate buffer saline (PBS)were used as negative controls. At the 6th week, serum titer of MG7-Ag specific antibody was detected by ELtSA.At the 8th week cellular immunity was detected by an unprimed proliferation test of the spleenocytes by using a [3H]-thymidine incorporation assay. Ehrlich ascites carcinoma cells expressing MG7-Ag were used as a model in tumor challenge assay to evaluate the protective effect of the vaccine.RESULTS: Serum titer of antibody against MG7-Ag was significantly higher in mice immunized with the vaccine than that in control groups (0.841 vs 0.347, P＜0.01; 0.841 vs 0.298,P＜0.01), while in vitro unprimed proliferation assay of the spleenocytes showed no statistical difference between those three groups. Two weeks after tumor challenge, 2 in 7 immunized mice were tumor free, while all the mice in the control groups showed tumor formation.
CONCLUSION: Oral DNA vaccine against the MG7-Ag momitope of gastric cancer is immunogenic. It can induce significant humoral immunity against tumor in mice, and the vaccine has partially protective effects.展开更多
基金the National Natural Science Foundation of China, No.39870742
文摘AIM: To develop an oral DNA vaccine against gastric cancer and evaluate its efficacy in mice.METHODS: The genes of the MG7-Ag mimotope and a universal Th epitope (Pan-DR epitope, PADRE) were included in the PCR primers. By PCR, the fusion gene of the two epitopes was amplified. The fusion gene was confirmed by sequencing and was then cloned into pcDNA3.1(+) plasmid. The pcDNA3.1 (+)-MG7/PADRE was used to transfect an attenuated Salrmonella typhimuriurm.C57BL/6 mice were orally immunized with 1x108 cfu Salrmonella transfectants. Salmonella harboring the empty pcDNA3.1(+) plasmid and phosphate buffer saline (PBS)were used as negative controls. At the 6th week, serum titer of MG7-Ag specific antibody was detected by ELtSA.At the 8th week cellular immunity was detected by an unprimed proliferation test of the spleenocytes by using a [3H]-thymidine incorporation assay. Ehrlich ascites carcinoma cells expressing MG7-Ag were used as a model in tumor challenge assay to evaluate the protective effect of the vaccine.RESULTS: Serum titer of antibody against MG7-Ag was significantly higher in mice immunized with the vaccine than that in control groups (0.841 vs 0.347, P＜0.01; 0.841 vs 0.298,P＜0.01), while in vitro unprimed proliferation assay of the spleenocytes showed no statistical difference between those three groups. Two weeks after tumor challenge, 2 in 7 immunized mice were tumor free, while all the mice in the control groups showed tumor formation.
CONCLUSION: Oral DNA vaccine against the MG7-Ag momitope of gastric cancer is immunogenic. It can induce significant humoral immunity against tumor in mice, and the vaccine has partially protective effects.
