Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 14 4 2019 12 29 552 562 EN Hai-Ting GUO Guangxi Key Laboratory for Brain and Cognitive Neurosciences, Guilin Medical College, Guilin, China AND College of Biological Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China Zhong-Yuan LI Guangxi Key Laboratory for Brain and Cognitive Neurosciences, Guilin Medical College, Guilin, China AND State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China Jin-Lei WANG State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China Zhao-Yu GENG College of Animal Science and Technology, Anhui Agricultural University, Hefei, China Xing-Quan ZHU State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China 2018 05 21 2018 10 20 Background: Toxoplasma gondii can infect all the warm-blooded vertebrates and cause serious toxoplasmosis. Extracellular signal-regulated kinase 7 in T. gondii (TgERK7) mediated the proliferation of this parasite may be a potential vaccine candidate. Thus, immune responses induced by TgERK7 were investigated in this study using a DNA vaccine strategy. Methods: pVAX/TgERK7 plasmid was constructed and used to immunize BALB/c mice for three times with two-week intervals. The challenge and the investigation of humoral and cellular immune responses were performed at two weeks post the last immunization, and the survival times of the infected mice were daily recorded until all of them were dead. Results: The innate immune response with higher concentrations of IFN-γ, TNF-α, IL2 and IL12p70 in sera (P < 0.05), and the adaptive immune responses were evoked by the DNA immunizations, including specific antibody, lymphocyte proliferation, and the CD3e+CD4+ and CD3e+CD8a+ T cell-mediated response effects. Interestingly, no significant difference was detected in their survival times among all the experimental groups of mice that were challenged with GT1 tachyzoites or PRU cysts (P>0.05). Conclusion: The successive immunizations with pVAX/TgERK7 can provoke the innate and adaptive immune responses of BALB/c mice, whereas the DNA vaccine-induced immunological efficacy is not sufficient for complete protection the host against T. gondii infection. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/2139