Anti-tumor efficacy and immune mechanism of gene vaccine expressing PSMA

AIM: To observe both the anti-tumor efficacy induced by gene vaccine expressing PSMA in mice and the feather of the specific immune responses, which may offer some theoretical knowledge and experimental foundation of the gene vaccine therapy for the prostate cancer.METHODS: pcDNA3.0-PSMA plasmids were injected into the hind-leg quadriceps muscle of the BALB/c mice. Anti-PSMA antibody was detected in sera of the animals. The proliferation and cytotoxicity of the spleen cells were observed. The immunized mice were inoculated subcutaneously in the right flank with sp2/0-PSMA cells. The anti-tumor efficacy of the gene vaccine was determined through the ratio of the tumor formation, tumor volume, tumor weight and the survival rate of immunized mice.RESULTS: High levels of anti-PSMA antibody were induced in the immunized mice. The splenocytes from vaccination group were stimulated to produce strong proliferative responses and significant cytotoxic T-cells (CTL) activity. Moreover, during a period of time, the antibody concentration, proliferation index and CTL activity appeared to go up as the time went by and the numbers of immunization increased. After DNA vaccine immunization, tumor occurrence decreased, the tumor-free time was prolonged and the growth velocity of tumor was markedly reduced (P<0.05).CONCLUSION: The humoral and cellular immunity is induced by PSMA gene vaccine. The anti-tumor efficacy in the immunized mice is produced strikingly.