FIG 5.

ΔTgPL1-infected mice have delayed TE and reduced brain inflammatory foci. (A) C57BL/6 mice were infected with 1,000 tachyzoites and monitored for survival. The graph is a compilation of 4 independent experiments, with 17 total mice infected with WT parasites, 18 mice infected with ΔTgPL1 parasites, and 12 mice infected with complemented ΔTgPL1 (comp) parasites. For statistical analysis, log rank (Mantel-Cox) values for WT versus ΔTgPL1 had a P value of <0.0001 and for ΔTgPL1 versus comp they had a P value of 0.0147, and differences were not significant for WT versus comp. (B) WT (W), ΔTgPL1 (Δ), or complemented ΔTgPL1 (C) parasites were grown as tachyzoites (Tachy) or bradyzoites (Brady) for 5 days. The bradyzoites were syringe lysed and grown under tachyzoite conditions for 24 (B→T 24 hr), 48 (B→T 48 hr), or 72 (B→T 72 hr) hours. The parasites were assessed for protein expression by Western analysis with anti-SAG1 (SAG1), anti-BAG1 (BAG1), or anti-β-tubulin (β-tub) as a loading control. Shown is a representative immunoblot from three independent experiments. (C) Example of a section of a wild-type-infected brain at 8 weeks postinfection. Sections were stained with hematoxylin and eosin and then scanned using light microscopy to identify aggregates of 10 or more inflammatory cells. The arrowheads indicate examples of foci. Scale bar = 50 μm. (D) Three C57BL/6 mice from two independent experiments (a total of 6 mice per strain) were infected with either WT (diamonds), TgPL1 (circles), or complemented (Comp) (triangles) parasites and allowed to establish a chronic infection for 8 weeks. After fixation, 5-μm sections were taken every 100 μm, providing 36 total sections per animal. Each symbol represents the total number of inflammatory loci counted in the 36 sections for each individual mouse, and the horizontal bars indicate the mean of each group. Significance was analyzed by one-way ANOVA. ***, P < 0.0001.