Figure 4.

Quantification of total and antigen-experienced CD8⁺ T cells in the brains of infected mice. (A) Time course of total cerebral lymphocyte counts during the late stages of blood infection. Mice were infected with WT (blue) or PRF (red) sporozoites by intravenous injection (n = 6 each), and cerebral lymphocytes were isolated and analyzed at indicated time points. Shown are total CD8⁺ T cell numbers. The dotted line represents the mean cerebral CD8⁺ T cell number in all naïve animals (n = 16). The scatter dot plots represent mean values (±SD). ^**P < 0.01 (Mann-Whitney test). (B) Gating strategy for detection of intracellular IFN-γ expression in CD3⁺CD8⁺ cells after re-stimulation with PbGAP50₄₀₋₄₈ peptide. Shown are representative plots for naïve animals, as well as mice infected with WT or PRF sporozoites. (C) Quantification of cerebral CD8⁺ T cells expressing intracellular IFN-γ after re-stimulation with PbGAP50₄₀₋₄₈ peptide. Shown are numbers of this population in the brain. The scatter dot plots represent mean values (±SD) from samples isolated on day 8 from three independent experiments (n = 10 each for infected mice; n = 4 for naïve mice). IFN-γ-secreting antigen-specific CD8⁺ T cells number from WT vs. PRF infected animals is non-significant. ^**P < 0.01 (Mann-Whitney test).