, *Fatemeh GHAFFARIFAR

Background: Severe and fatal complications of toxoplasmosis urge development of effective vaccines against the disease. The current study was performed to evalu-ate cocktail DNA vaccine containing plasmids encoding GRA5, SAG1, and ROP2 genes of Toxoplasma gondii in BALB/c mice in Tarbiat Modares University in 2012. Methods: The plasmids containing complete GRA5, SAG1, and ROP2 genes were mass extracted and then the recombinant plasmids were administered via intramus-cular injections according to immunized mice three times with three-week intervals. Then splenocytes were cultured, and proliferation as well as cytokine assays were carried out. The other mice in each group were inoculated by the parasite and mor-tality of the mice was evaluated on a daily basis. Results: The results of cytokine assay for INF-γ were higher in the mice that re-ceived the cocktail DNA containing recombinant plasmids. Evaluation of prolifera-tion of splenocytes using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetra-zolium bromide) assay indicated induction of cellular response. Measurement o