Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 15 3 2020 09 12 349 356 Meysam SHOKRI Department of Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran Khosro HAZRATI TAPPEH Department of Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran Elyar MESHKINI Department of Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran Arash AMINPOUR Department of Parasitology and Mycology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran 2020 09 12 Background: In this study, the effect of total lysate antigen (TLA) of Toxoplasma gondii on spleen lymphocyte prolifration, secretion of IL5, INF-γ, and mice survival time was evaluated using agonist of toll-like receptor (TLR) 11, as an adjuvant. Results: Mice immunized with TLA + adjuvant showed higher immunization index than the two other groups and combination of TLR11 (as an adjuvant) and TLA significantly elevated the effect of TLA by increasing the production of INF-γ and IL-5 and by the shift of the immune system to Th1. In addition, the combination of TLA and TLR11 adjuvant increased the proliferation of lymphocytes and survival time in mice against T. gondii. Conclusion: Profilin (as an adjuvant) in combination with TLA could be a potent vaccine candidate that evokes a powerful specific immune response and significantly improves the efficacy of TLA vaccine by increasing the induction of INF-γ production and by shifting the immune responses to Th1 profile through increasing the INF-γ/IL-5 ratio. It causes significant protection against T. gondii after i.p. injection. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/3061 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/3061/1064