[Construction of human MAGE-3 DNA vaccine and its immune effects observed in vivo].

To investigate the antitumor immune responses induced by MAGE-3 DNA vaccine, the recombinant mammalian expression plasmid pcDNA3.1/MAGE-3 was constructed by ligating MAGE-3 gene, which was amplified by RT-PCR, and the pcD-NA3.1 + vector. The recombinant plasmids were transfected into B16 cells by liposome, the expression of MAGE-3 was checked by RT-PCR, immunocytochemistry and Western blot. Then, 100 ug recombinant plasmids were injected intramuscularly per C57BL/6 mouse on 0, 10 and 20 days, with pcDNA3.1 + plasmid and PBS as controls. Splenocytes CTLs, the level of antibodies against MAGE-3 the changes of the T lymphocyte subsets and the levels of cytokines were checked after 3 times immunization. As a result, the mice immunized with pcDNA3.1/MAGE-3 plasmid can produce MAGE-3 specific immune response. The CTLs kill activities against B16/MAGE-3 cells was 51.08 +/- 7.41%, and had significant difference (P < 0.01) compared with that of pcDNA3.1 + group (8.44 +/- 1.89%) and PBS group (5.76 +/- 1.75%). The titre of antibody against MAGE-3 was 1:15, while controls were negtive. The number of CD4 + CD8 + and the levels of IFN-gamma IL-2 increased significantly after immunization with pcDNA3.1/MAGE-3 plasmid as compared with those of control groups (P < 0.01). It is concluded that the pcDNA3.1-MAGE-3 DNA vaccine are able to induce both cellular and humoral immune responses in vivo.