RESUMO
Objective:To analyze whether the OAZI-1 (ornithine decarboxylase antizyme inhibitor-1) protein complex isolated from tumor cells could induce specific antitumor effects in the experiment mice .Methods:OAZI-1 protein complexes were isolated from B16-F1 melanoma cells by immune magnetic beads coated with OAZI-1 antibody and used as the vaccine to immune the C 57BL/6 mice.After immunization,the mice were inoculated subcutaneously with live B 16-F1 cells and then tumor formation and growth were ob-served.ELISA was used to determine the level of cytokine IFN-γin the serum of immunized mice.Lactate dehydrogenase assay (LDH) was performed to evaluate killing effect of spleen lymphocytes on B 16-F1 cells.The mice immunized by purified OAZI-1 from prokaryotic expression and PBS were used as controls in the animal experiment .Results: Compared with the control mice ,the spleen lymphocytes ( effector cells ) from the mice inoculated with OAZI-1 protein complexes had stronger killing ability on B 16-F1 cells (target cells).At three different effector:target ratio (10:1,50:1,100:1),the killing ability of these spleen lymphocytes were 46.2%, 59.5%and 92.5% respectively,which was significantly higher than the spleen lymphocytes from the mice inoculated with purified AZIN-1 protein (36.1%,26.8% and 45.9%) or inoculated with PBS (24.6%,24.0% and 27.2%).In addition,the content of serum anti-tumor cytokine IFN-γwas also significantly higher in the mice inoculated with OAZI-1 protein complexes (538.3 pg/ml) than the mice inoculated with purified AZIN-1 ( 256.2 pg/ml ) or with PBS ( 131.0 pg/ml ) .When B16-F1 live cells were subcutaneously inoculated into the immunized mice described above ,the tumor formation rate was only 40%in the mice immunized with OAZI-1 protein complex ,but 100%in the mice immunized with PBS or purified OAZI-1.The growth of inoculated tumors in the mice immunized with OAZI-1 protein complex was also much slower than the control mice .Conclusion:The results in this study suggest that the OAZI-1 protein complex isolated from B 16-F1 tumor cells could contain some tumor antigens .When used as tumor vaccine to inoculate mice ,this complex can induce anti-tumor immune killing activity in experimental animals .
RESUMO
Objective To investigate whether ornithine decarboxylase antizyme inhibitor-1(OAZI-1) can enhance the immunogenicity of Melan-A and induce antitumor immune effect in the experimental animals.Methods The eukaryotic expression plasmid pcDNA3.1(-) /OAZI-1, pcDNA3.1 (-)/Melan-A and pcDNA3.1(-)/Melan-A-OAZI-1 were constructed and used to immunize BALB/c mice.The spleen lymphocytes were prepared from the immunized mice and then used to determine the lymphocyte subsets by flow cytometry assay and tumor-killing activity by LDH release assay.The blood samples were collected from the immunized mice and used to test the serum INF-γ by ELISA.Results The eukaryotic expression plasmid pcDNA3.1(-)/OAZI-1, pcDNA3.1(-)/Melan-A and pcDNA3.1(-)/Melan-A-OAZI-1 were successfully constructed.All three gene vaccines could increaseCD4+ T cell ratio (P<0.05), among of them, the ratio in the pcDNA3.1(-)/Melan-A-OAZI-1 and pcDNA3.1(-)/Melan-A immunized groups increased more significantly than other groups but no obvious differences was observed between these two groups.Similarly, all three gene vaccines could also increased CD8+T cells ratio significantly (P<0.05), but, comparing with all other groups, the highest increase was observed in the pcDNA3.1(-)/Melan-A-OAZI-1 immune group (P<0.05).The pcDNA3.1(-)/Melan-A-OAZI-1 gene vaccines significantly increased cytotoxic activity of the spleen lymphocyte in the immune mice(P<0.05).Among the three gene vaccines only pcDNA3.1(-)/Melan-A-OAZI-1 could significantly increased the INF-γ level in the mice serum (P<0.05).Conclusions OAZI-1 can improve antitumor immunity by promoting tumor antigen presentation.