Study on antitumor effect of minigene DNA vaccine derived from Carcinoembry-onic Antigen ( CEA) gene in mice / 中国免疫学杂志

ABSTRACT

Objective:To observe the immunological activity of haploid vaccine and three tandem repeats of minigene DNA vac -cine derived from Carcinoembryonic Antigen (CEA) gene.Methods:The immunoreaction was induced by intramuscular injection with pc-DNA3.0,pcDNA-CEA625-667 and pcDNA-triCEA625-667 in BALB/c.Four weeks after injection,the spleen cells and serum were separa-ted respectively from the mice for the in vitro assessment .Changes of the T lymphocytes subset was analyzed by flow cytometry .Lymph proliferation responses were tested by 3 H-TdR incorporation ,IFN-γ,IL-4 and GM-CSF in their cultural supernatants were detected with ELISA and seral IgG antibody against CEA were detected with Western blot and ELISA .Results:The difference of the ratio of CD 4+/CD8+of the mice immuned by pc-DNA3.0,pcDNA-CEA625-667 or pcDNA-triCEA625-667 was not significant.Lymph proliferation responses were more significant in the mice immuned by pcDNA-CEA625-667 and pcDNA-triCEA625-667 in a shorter time by contrast with na ?ve mice.Low tilter IgG antibody against CEA was detected in the antiserum of the mice immuned by repeats of minigene DNA vaccine , which suggested the activation of helper T-cell.ELISA showed that the level of IFNγin the 3 days culture of the splenocytes was rela-tively higher in the groups of minigene DNA vaccination than in the control groups ,while IL-4 expression was absent in all groups .The immune response level elicited by three tandem repeats of minigene DNA vaccine pcDNA -triCEA625-667 was superior to that elicited by pcDNA-CEA625-667 ,which showed that any immunogenic inadequacies in minigene presentation can be rectified by linking itself in a string-of-beads vaccine.Conclusion:The haploid vaccine and three tandem repeats of minigene DNA vaccine derived from CEA geneboth can not change the ratio of CD 4+/CD8+but can induce the activation of helper T-cell and skew T -cells toward Th -1 response.The immune response level elicited by three tandem repeats of minigene DNA vaccine was superior to thatelicited by haploid vaccine .