DNA vaccine ROP29 from Toxoplasma gondii containing R848 enhances protective immunity in mice

Aims: Toxoplasma gondii is an intracellular parasite that causes a global epidemic parasitic disease. Studies using DNA vaccines for the control of toxoplasmosis have made considerable progress. ROP proteins were proven to be excellent candidates for T. gondii DNA vaccine development. Methods and Results: Here, a ROP29 DNA vaccine was successfully produced and injected into mice in combination with R848 to evaluate its ability to provide protection against T. gondii challenge. Compared with other mice, the mice injected with R848/pROP29 produced higher levels of IgG, IgG2a, interleukin (IL)-12, and interferon gamma (IFN-gamma). Moreover, after a challenge of 20 T. gondii cysts, the number of brain cysts was lower in the R848/pROP29-immunized mice than in the other experimental mice. Conclusions: R848 could improve the productions of IL-12 and IFN-gamma, thus enhancing the immune responses stimulated by the pROP29 DNA vaccine.