Figure 4

Absence of PD-L1 led to increased expression of PD-1 on T cells with no difference in Foxp3 ⁺ T cells in the spleens. Splenocytes from WT, PD-L1^-/-, and PD-L2^-/- mice were harvested at 96 hours post-MCAO or sham-treatment and assessed for expression. (A) PD-1 expression on gated CD4⁺ T cells. (B) PD-1 expression on gated CD8⁺ T cells. (C) Expression of Foxp3⁺CD4⁺ T cells. Values represent mean numbers (± SEM) of indicated cell subsets from four to five mice of each group, from two separate experiments. Statistical analysis was performed with ANOVA followed by Tukey’s multiple comparison post-hoc test. Significant differences between sample means are indicated (#P ≤0.05 and ###P ≤0.001 as compared to their respective sham;*P ≤0.05 and **P ≤0.01 compared to the PD-L1^-/- mice post-MCAO). ^-/^-, knockout; ANOVA, analysis of variance; MCAO, middle cerebral artery occlusion; PD-1, programmed death-1; PD-L1, programmed death-1 ligand 1; PD-L2, programmed death-1 ligand 2; SEM, standard error of the mean; WT, wild-type.