FIG. 6.

CD4⁺ T cells are the main producers of T-cell-associated IFN-γ within the brains of V3533-infected μMT mice. Female μMT mice (7 to 10 weeks old) were inoculated with 10³ PFU of V3533 by injection in the left rear footpad. At the times indicated, mice were perfused with PBS and brain-infiltrating leukocytes were isolated. (A and B) Harvested cells were then pooled and either cultured in the presence of PMA-ionomycin for 6 h with brefeldin A with or without monensin added for the final 4 h (A) or cultured in the presence of brefeldin A with or without monensin with no additional stimulus for 4 h (B). Following treatment, cells were surface stained for CD3α, CD4, and CD8 and then stained for the intracellular presence of multiple cytokines. Each bar represents the number of cells of a given cell type that stained as positive for the indicated cytokine-surface marker per brain (days 8 and 15) or the percentage of pooled cells that stained as positive (day 70). (C) Percentages of T cells positive for CD69 surface expression in the absence of ex vivo stimulation. Data shown were generated in a single experiment but are representative of 2 to 3 independent experiments.