DNA-liposome Vaccination With Genes Encoding Toxoplasma Gondii Antigens SAG1 And ROP1 Induces Partially Protective Immunity Against Lethal Challenge In Mice

IntroductionToxoplasma gondii is an intracellular protozozan parasite that infects a wide variety of vertebrate hosts, including humans. Although Toxoplasma gondii most often causes subclinical infection, primary infection during preganency can induce fetal pathology and abortion in both humans and lower animals. In the chronic phase, reactivation of the infection can be life-threatening for immunocompromised individuals such as AIDS patients, some organ-transplanters and tumor suffers. So the prevetion to the infection with the parasite is an acute problem which associates with public health and social economy. A vaccine against Toxoplasma gondii would be extremely valuable for preventing both fetal infection and reactivation in immunopromised people. It might reduce economic losses due to abortion in farm animals.In the present study, mice were immunized with plasmid DNAs encoding two distinct Toxoplasma antigens: SAG1 and/or ROP1, which are expressed respectively in the tachyzoite and bradyzoite life stages of the parasite. SAG1 (P30) is a major surface antigen that has been demonstrated development of significant protection in animal models. ROP1 is one of the immunogenic rhoptry proteins, which is related to the penetration enhancing factor of the parasite. It has been determinated that the antibodies against the two antigens could offer protection of host cells from invasion of Toxoplasma gondii. We describe here the development and evaluation of DNA...