Splenic distribution of PD-L1 expression after infection. (A and B) The geometric mean fluorescent intensity (GMFI) of PD-L1 expression (mean ± SD) was quantified on splenic marginal zone macrophages (CD45⁺ Thy1.2⁻ F4/80⁻ CD209b⁺; MZM), myeloid dendritic cells (CD45⁺ Thy1.2⁻ F4/80⁻ CD169⁻ CD209b⁻ CD11c⁺ CD11b⁺; mDCs), red pulp macrophages (CD45⁺ Thy1.2⁻ CD169⁻ CD209b⁻ CD11c⁻ CD11b⁺ F4/80⁺; red pulp Mϕ), metallophilic macrophages (CD45⁺ Thy1.2⁻ F4/80⁻ CD169⁺; MMM), CD8α DCs (CD45⁺ Thy1.2⁻ F4/80⁻ CD169⁻ CD209b⁻ CD11b⁻ CD11c⁺ CD8α⁺), CD8 T cells (CD45⁺ Thy1.2⁺ CD8α⁺), and CD4 T cells (CD45⁺ Thy1.2⁺ CD4⁺) at days 4 and 7 after Arm or CL13 infection. Total expression of PD-L1 on the denoted cell populations was defined as PD-L1 GMFI minus the isotype control GMFI. Naive mice were used as a control at both time points (n = 4–5 mice). Asterisks denote statistically significant differences between the Arm and CL13 groups (P < 0.05). (C) Representative 3-color splenic images show the distribution of PD-L1 (red), LCMV (blue), and laminin (green) in naive, day 7 Arm, and day 7 CL13-infected mice (n = 4 mice). All data in this figure are representative of two independent experiments.