title: Toxoplasma gondii: DNA vaccination with bradyzoite antigens induces protective immunity in mice against oral infection with parasite cysts.
abstract: Infection of the host by Toxoplasma gondii leads to an acute systemic dissemination of tachyzoites, followed by a chronic phase, in which bradyzoites, enclosed in cysts, persist in the brain, the heart, and other tissues. Among putative vaccine candidates, the bradyzoite antigens BAG1 and MAG1 look promising since they are preferentially expressed during the chronic stage of the parasite. This work focused on studying the immunogenicity of bradyzoite antigens in a mouse model of chronic toxoplasmosis. A mixture of plasmids directing the cytoplasmic expression of MAG1 and BAG1 in mammalian cells was used to immunize mice. We show here that immunized mice developed, preferentially, specific anti-MAG1 and anti-BAG1 IgG2a subclass antibodies, indicating a shift towards a Th1-like response after DNA immunization. We then demonstrated that DNA immunization followed by challenge infection elicited effective protection in mice, suggesting that bradyzoite antigens should be considered in the design of vaccines against toxoplasmosis.
authors.affiliation: Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Henrik V
authors.initials: HV
authors.lastname: Nielsen
authors.forename: Manlio
authors.initials: M
authors.lastname: Di Cristina
authors.forename: Elisa
authors.initials: E
authors.lastname: Beghetto
authors.forename: Andrea
authors.initials: A
authors.lastname: Spadoni
authors.forename: Eskild
authors.initials: E
authors.lastname: Petersen
authors.forename: Nicola
authors.initials: N
authors.lastname: Gargano
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology*; D001921:Brain / Q000469:parasitology; D019556:COS Cells; D002522:Chlorocebus aethiops; D004195:Disease Models, Animal; D005260:Female; D005455:Fluorescent Antibody Technique; D006360:Heat-Shock Proteins / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D008809:Mice, Inbred C3H; D010957:Plasmids / Q000276:immunology; D015800:Protozoan Proteins / Q000276:immunology*; D016052:Protozoan Vaccines; D014122:Toxoplasma / Q000276:immunology* / Q000302:isolation & purification; D014124:Toxoplasmosis, Animal / Q000276:immunology / Q000517:prevention & control*; D014162:Transfection; D019444:Vaccines, DNA
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; C106179:BAG1 protein, Toxoplasma; D006360:Heat-Shock Proteins; D007074:Immunoglobulin G; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA