Abstract: 　AIM: To observe the immune responses in BALB/c mice vaccinated with the constructed recombinant plasmid, pcDNA3, containing ROP1 gene from Toxoplasma gondii. METHODS: The plasmid DNA obtained by alkaline lysis were injected into the left leg of each mouse at a dosage of 100 μg. A booster vaccine was given using the same dosage two weeks later. Control groups were injected with the pcDNA3 blank plasmid and normal saline, respectively. 30, 50 and 70 days after the booster injection, the proliferation activity of T lymphocytes and the NK cell activity were determined using MTT assay, the number of CD4+/CD8+ T cells with indirect immunofluorescence assay and the titer of IgG antibody by ELISA. RESULTS: The spleens of mice enlarged obviously after immunization with pcDNA3-ROP1. The activity of proliferation of spleen T lymphocytes was higher in the immunization group than in the control groups; The NK cell activity in the immunization group was higher than those of control ones. The number of CD4+ T cells showed no obvious increase but CD8+ T cells obviously increased. The titer of IgG antibody in the immunization group showed no significant increase until 90 days later. CONCLUSION: Vaccination of mice with the recombinant plasmid, pcDNA3-ROP1, could elicit cellular and humoral immune response in mice. \;

Key words: Toxoplasma gondii, rhoptry protein1(ROP1), pcDNA3-ROP1 recombinant plasmid, DNA vaccination