Avicenna J Med Biotech arij002 Avicenna Journal of Medical Biotechnology 2008-2835 2008-4625 Avicenna Research Institute ajmb297 Evaluation of Immune Responses Induced by <i>GRA7</i> and <i>ROP2</i> Genes by DNA Vaccine Cocktails Against Acute Toxoplasmosis in BALB/c Mice VaziniHosseinGasteroenterohepatology Research Center, Nemazee Hospital, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IranDepartment of Biochemistry, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, IranGhafarifarFatemehEndocrinology and Metabolism Research Center, Nemazee Hospital, Shiraz University of Medical Sciences, Shiraz, IranDepartment of Biochemistry, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, IranSharifiZohrehDepartment of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, IranDalimiAbdolhossein 10 1 2 8 7 11 2016 4 3 2017

<p>Background: The severe damages of toxoplasmosis clearly indicate the need for the development of a more effective vaccine. Immunization with plasmid DNA is a promising vaccination technique. Therefore, <em>GRA7</em> plasmid was prepared to be used as a vaccine. The purpose of this study was evaluation of immunization with cocktail DNA vaccine including plasmids encoding <em>Toxoplasma gondii</em> <em>ROP2</em> and <em>GRA7</em> in BALB/c mice.<br /> Methods: In this study, 733 <em>bp</em> of <em>GRA7</em> gene was cloned in pCDNA3.1 plasmid as an expression vector. The plasmids containing <em>GRA7</em> and <em>ROP2</em> genes were administered via <em>IM </em>according to immunized mice three times with a 3 week interval. For lymphocyte proliferation and cytokine assay, splenocytes of immunized mice were cultured for proliferation and cytokine assay. The other mice in each group were inoculated by the parasite and mortality of the mice was evaluated on a daily basis.<br /> Results: The cytokine assay results and lymphocyte proliferation response in cocktail DNA vaccines showed that IFN-&gamma; levels were significantly higher than controls (p&lt;0.05), whereas IL-4 expression level in BALB/c mice immunized with cocktail was lower than that in control groups and these results are confirmed by MTT test. Predominance of the levels of IgG2a over IgG1 was observed in sera of the immunized mice. Furthermore, IgG2a values in cocktail DNA vaccines pcGRA7 were significantly higher than control group (p&lt;0.01). In contrast, IgG1 antibodies were similar between the two groups (p&gt;0.5). So, survival time in the immune groups was significantly prolonged in comparison to control ones (p&lt;0.01).<br /> Conclusion: The immunized mice by DNA vaccine produce higher titration of IFN&gamma;, indicated with Th1 response which is confirmed by high level of IgG2a. These data demonstrate that the cocktail <em>GRA7/ROP2</em> is a potential vaccine candidate against toxoplasmosis.</p>