Vaccination of mice with the protective F3G3 antigen of Toxoplasma gondii activates CD4+ but not CD8+ T cells and induces Toxoplasma specific IgG antibody.
A major cytoplasmic Toxoplasma gondii (T. gondii) antigen recognized by monoclonal antibody F3G3 (F3G3-Ag), as well as two surface antigens recognized by monoclonal antibodies 2G11 and 1E11 respectively (2G11-Ag; 1E11-Ag), were isolated from crude Toxoplasma sonicates using affinity chromatography. Purified F3G3-Ag induced long term protection against Toxoplasma infection in mice and induced Toxoplasma specific IgG antibody. CD4+ but not CD8+ T cells from immune animals proliferated and produced IL-2 upon restimulation with either Toxoplasma sonicate or F3G3-Ag in vitro. Furthermore, CD4+ T cells from mice immunized with F3G3-Ag responded to purified 2G11- and 1E11-Ag. In contrast, CD4+ T cells from mice immunized with 2G11-Ag responded to Toxoplasma sonicate and 2G11-Ag, but not to F3G3- or 1E11-Ag. The results may indicate that the protective F3G3-Ag shares immunogenic epitopes present also on 2G11- and 1E11-Ag, since the F3G3-Ag used for the vaccination did not contain detectable amounts of 2G11- or 1E11-Ag, and none of the antigens displayed any mitogenicity. Taken together the results show that the cytoplasmic F3G3-Ag of T. gondii induces CD4+ T helper cells, Toxoplasma specific IgG antibodies and long term protection against Toxoplasma infection, but does not induce detectable sensitization of the CD8+ T cell compartment.
Brinkmann
V
V
Department of Medicine, Stanford University School of Medicine, CA 94305.
Remington
J S
JS
Sharma
S D
SD
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects*; D016827:CD8 Antigens / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000096:biosynthesis* / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008808:Mice, Inbred CBA; D015800:Protozoan Proteins / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014124:Toxoplasmosis, Animal / Q000276:immunology / Q000517:prevention & control; D014611:Vaccination
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016827:CD8 Antigens; C080361:F3G3 antigen, Toxoplasma gondii a; D007074:Immunoglobulin G; D007376:Interleukin-2; D015800:Protozoan Proteins; D016052:Protozoan Vaccines