Figure 5.

Aged neutrophils play an immunosuppressive function through PD-L1 and arginase-1. (A, B) PBMCs were co-cultured with neutrophils derived from an in vitro culture for 0 h, 24 h at a 1:3 ratio. Statistical analysis of CD8⁺ T cells secreting IFN-γ (A) and TNF-α (B). (C, D) PBMCs were stimulated by anti-CD3 (1 μg/ml) and anti-CD28 (1 μg/ml) antibodies with or without neutrophils from TN patients at a 1:3 ratio for 12 h in the presence or absence of a specific PD-L1-blocking antibody or arginase-1 inhibitor (nor‐NOHA). Cumulative IFN-γ (C) and TNF-α (D) expression was measured via intracellular cytokine staining of CD8⁺ T cells. For statistical analyses, Mann–Whitney U-test was performed. *p < 0.05, **p < 0.01, ns, not significant.