Fig 8.

Immunization with AS15 peptide lowers the cyst burden and parasite load in the brains of infected mice. C57BL/6 mice were immunized with LPS-activated BMDCs pulsed with AS15 or control peptide (OVAp). Seven days postimmunization, these mice were infected with 1 × 10⁴ live T. gondii tachyzoites, intraperitoneally. Panels show analysis of CD4 responses and parasite loads from infected mice. (A) IFN-γ response by brain CD4 T cells as measured by ICCS for IFN-γ using flow cytometry after ex vivo restimulation with AS15-pulsed APCs. Data are background corrected based on the values from APCs pulsed with irrelevant peptide. (B) MHC class II I-A^b–AS15 tetramer staining on brain leukocytes. Cells were also costained with CD4 antibody. (C) Number of cysts in the brain as measured by staining a portion of the brain with fluorescent lectin to detect the cysts. (D) The parasite load in the brain measured using semiquantitative PCR on genomic DNA extracted from the tissue. The data in panels A through D are compiled from three experimental groups analyzed at days 28 and 30 after challenge with at least 4 mice per condition in each experiment. *, P < 0.05; **, P < 0.01.