Figure 5.

Lack ofTgMCA did not affect intracellular parasite replication but did affect parasite viability in the extracellular environment. (A) Plaque assay comparing growth of ΔTgMCA, Δku80, and TgMCA OE. Each well (HFF cell) was infected with 500 parasites, and plaques were stained 7 days later. Data were compiled from three independent assay. (B) The plaque areas were counting by randomly chosen at least 50 plaques and using the Pixel point in Photoshop C6S software (Adobe, USA), and the data were compiled from three independent experiment. Analysis of plaque area was performed using One-way ANOVA with Tukey's post-hoc comparison. Asterisks indicated significant results (p ≤ 0.05). (C) Intracellular parasite replication of ΔTgMCA, Δku80, and TgMCA OE. Data were compiled from three independent assay, and in each assay 100 total PVs of each strain were counted. Data were determined by Chi-square analysis. (D) Invasion ratio of ΔTgMCA, Δku80, and TgMCA OE, freshly isolated and pre-incubated in extracellular buffer for 1 or 2 h. The ratio was based on the number of cells infected with parasites divided by the number of total cells in one field of view. Asterisks indicated statistically significant results (p ≤ 0.05 as determined by Two-way ANOVA with Tukey's post-hoc comparison). Data are mean ± SD (error bars) of three independent experiment. (E,F) Mouse survival after infection with different doses of ΔTgMCA, Δku80, and TgMCA OE. Balb/c mouse were injected intraperitoneally (i.p.) with 100 or 10 indicated parasites. There were 5 female mice in each group, statistical analysis was performed using life test (life test data = surv) in statistical analysis system (SAS institute Inc., USA). The figures are representative of three experiments (a dose of 100 tachyzoites) and two experiments (a dose of 10 tachyzoites) with similar outcomes.