DNA (deoxyribonucleic acid) vaccine for preventing chronic toxoplasmosis of humans or animals

The invention discloses a DNA (deoxyribonucleic acid) vaccine for preventing the chronic toxoplasmosis of humans or animals. The recombinant DNA vaccine is obtained by respectively inserting three antigens SAG2C, SAG2D and SAG2X on toxoplasma gondii bradyzoite into a eukaryotic vector pVAX1 to obtain recombinant plasmids pVAX1-SAG2C, pVAX1-SAG2D and pVAX2-SAG2X and mixing the three recombinant plasmas. The DNA vaccine is used for carrying out active immunity on a BALB/c mouse, then evaluating the immunogenicity of the vaccine by measuring cell and humoral immunity indexes of the immune mouse and evaluating the immunizing protection by calculating the quantity of cysts in the brain after a toxoplasma gondii attack experiment of the mouse. The DNA vaccine disclosed by the invention can be used for effectively enhancing the humoral immunity and cellular immune response and effectively reducing the formulation rate of brain cysts after the immune mouse is attacked by a toxoplasma gondii PRU strain (II type). The