Figure 2.

NOS2 is not required for the CD8⁺ T cell-initiated immune process to remove T. gondii cysts from the brain. RAG1^−/− and RAG1^−/−NOS2^−/− mice were infected with 20 cysts of the ME49 strain perorally and treated with sulfadiazine beginning at 9 days after infection to establish a chronic infection in their brains. At 3 weeks after infection, the mice received a systemic transfer of CD8⁺ immune T cells (3.2 ×10⁶ cells) from chronically infected BALB/c mice (Day 0). As a control, a group of infected RAG1^−/− and RAG1^−/−NOS2^−/− mice received CD8⁺ normal T cells from uninfected BALB/c mice in the same manner. Seven days after the T cell transfer (Day 7), numbers of T. gondii cysts (A) and the amounts of bradyzoite-specific BAG1 mRNA (B) in their brains were measured. All data represent mean ± SEM. The data from two independent studies were combined. There were 3 or 4 mice in each experimental group in each experiment. *Pc<0.05, **Pc<0.01, and ***Pc<0.001. N.S.: not significant.