[Development of oral DNA vaccine based on MG(7)-Ag mimotope of gastric cancer].
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 x 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 8th week, a [(3)H]-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.


CONCLUSIONS
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.
Guo
Changcun
C
PLA Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China.
Ding
Jie
J
Yu
Zhaocai
Z
Han
Quanli
Q
Meng
Fanping
F
Liu
Na
N
Fan
Daiming
D
D000284:Administration, Oral; D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm / Q000097:blood / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D018716:Molecular Mimicry / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000276:immunology; D016896:Treatment Outcome; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use*
D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D000939:Epitopes; D019444:Vaccines, DNA