Figure 4.

Effects of transfer of CD8⁺ T cells on cyst burden in the brain. (a) Wild-type (WT) CD8⁺ T cells (CD8/WT), WT CD4⁺ T cells (CD4/WT) and signal transducer and activator of transcription (STAT) 6^−/− CD8⁺ T cells (CD8/ST) were purified from infected mice on day 14 post-infection (pi). Then 5 × 10⁶ of these cells were injected intravenously into STAT6^−/− mice that had been infected 14 days previously. The cyst burden in the brain was then determined on day 28 pi. (b) The percentage of CD25⁺ CD8⁺ T cells in CD8⁺ T cells in cerebrospinal fluid (CSF) was determined on day 28 pi. Data are mean ± standard deviation (SD) (n = 5). (c) Five million CD8⁺ T cells from uninfected WT mice (naïve CD8/WT) were transferred into STAT6^−/− mice which were simultaneously infected with Toxoplasma gondii. The percentage of CD25⁺ CD8⁺ T cells in CD8⁺ T cells in peripheral blood was determined on day 14 pi. (d) Cysts in the brains of these mice were determined on day 28 pi. Data are mean ± SD (n = 5). Experiments were carried out three times, with similar results. *Significantly different (P <0·05).