Figure 5.

PD-L1 is upregulated during the monocyte-macrophage maturation/differentiation process

(A and B) Freshly isolated PBMCs from newly diagnosed patients with BC (n = 12) were ex vivo rested in RPMI 1640 with 10% FBS for 8 h. PD-L1⁺% peripheral blood monocytes are shown in representative flow plots (A) and compared between fresh vs. rested monocytes (B).

(C and D) PD-L1⁺% between in suspension vs. adherent monocytes after 8 h resting (n = 8) are shown in representative flow plots (C) and compared (D).

(E and F) PD-L1⁺% monocytes between flow sorted fresh PBMCs vs. 8 h rested PBMCs (n = 5) are shown in representative flow plots (E) and compared (F). Paired t test.

(G and H) MFI ratio of surface protein levels (G) and phosphorylated signal transduction protein levels (H) on PD-L1⁺ vs. PD-L1^– monocytes in 8 h rested PBMCs from patients with BC. Wilcoxon paired test.

(I) Peripheral blood monocytes from patients with BC (n = 6) were treated with small-molecule inhibitors (Selleck) against ERK1/2 (SCH772984 at 0. 5 μM), STAT1 (fludarabine at 50 μM), Akt1/2/3 (MK-2206 2HCl at 0.5 μM), PI3Kα/δ/β (LY294002 at 5 μM), NF-κB (QNZ at 5 μM), and mTOR (rapamycin at 0.1 μM) during the 8 h resting. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗p < 0.0001. Shown are mean ± SEM.