Biological role of surface Toxoplasma gondii antigen in development of vaccine

Figure 1 A strong band at 30 ku position after reaction with serum from mice infected with T. r-SAG1 of Toxoplasma gondii tachyzoites. The band was electrophoresed on SDS-12% polyacrylamide gel and then transferred onto a nitrocellulose membrane probed with sera (diluted at 1:100) from PBS-inoculated mice (lanes 1 and 2) or from mice infected with crude antigens of T. gondii (lanes 3 and 4). Bound antibodies were detected using anti-mouse-alkaline phosphatase conjugate. The positions of molecular masses are shown on the left.

Figure 2 Protection of r-SAG1 against infection with tachyzoites of Toxoplasma gondii. Sixteen BALB/C mice were immunized with r-SAG1 of T. gondii and 11 mice were injected with PBS as a control. The mice were challenged with 1X10⁵ tachyzoites of Toxoplasma gondii RH at 9 wk post immunization. The number of the dead mice was counted.

Figure 3 Antibody responses to r-SAG1. BALB/C mice were immunized with 30 µg r-SAG1 of T gondii or with PBS as a control. Booster was done with Freund’s incomplete adjuvant 2 wk after the first injection. Three weeks post-immunization, sera were collected from 5 mice of each group. Antibodies were tested individually by ELISA.

Figure 4 Profile of cytokines induced by r-SAG1 in PBS-inoculated mice (A) or r-SAG1 of T gondii immunized mice (B). Crude antigens of Toxoplasma gondii tachyzoites were electrophoresed on SDS-12% polyacrylamide gel and then transferred onto a nitrocellulose membrane probed with sera (diluted at 1:100). Bound antibodies were detected using anti-mouse-alkaline phosphatase conjugate. The positions of molecular masses are shown on the left.

Figure 5 Production of cytokines induced by r-SAG1. BALB/C mice were immunized with r-SAG1 of T gondii or with PBS as a control. Six weeks after immunization, cytokines were tested individually by ELISA in 5 mice of each group.

Figure 6 Effects of monoclonal antibody to r-SAG1 on tachyzoites of Toxoplasma gondii. A: Agglutination of the parasites, hole and gap formation on the surface, destroyed parasites and membrane thickness; B: Deformed parasite; C: Swollen parasites.Toxoplasma gondii tachyzoites were collected from mice and washed with PBS. Monoclonal antibody mAb2B3 to r-SAG1 from mouse ascites fluid was diluted and reacted with the parasites and observed under electro-microscope at 6800 x.