Compromised CD8 effector function in the central nervous system of CD4-depleted B7-H1
mice. Infected B7-H1−/− mice were treated with α-CD4 or control α-βgalactosidase (α-βgal) monoclonal antibody at 4 and 6 days post-infection (p.i) (A) Pooled brain cells (n ≥ 4/group) isolated at days 7 and 10 p.i. were stained for CD8, Db/S510-specific T-cell receptor and intracellular granzyme B. Representative density plots gated on CD8 T cells depict α-granzyme B and Db/S510 tetramer staining. Mean fluorescence intensity (MFI) of granzyme B in Db/S510 tetramer+ CD8 T cells is shown in the upper right-hand quadrant. Data are representative of three independent experiments. (B) CNS interferon (IFN)-γ protein determined by ELISA at the indicated days p.i. Data represent the mean ± SEM (n ≥ 6/group) of two separate experiments. Significant differences were determined by the unpaired t-test. *** P<0.001. (C) Transcript levels of IFN-γ, perforin and interleukin (IL)-10 in CD8 T cells purified by fluorescence-activated cell sorting from the pooled brains of n = 6 to 8 mice collected at 7 and 10 days p.i. assessed by PCR. Transcript levels relative to GAPDH × 1000 are presented as fold change with levels from B7-H1−/− α-βgal day 7 p.i. samples set to 1. Data depict the mean ± SEM of two independent experiments.