Fig. 3

Tumor-derived factor TNF-α induces mast cells to express PD-L1. a Statistics analysis of PD-L1⁺ mast cell percentage in total mast cells in each samples of patients with GC (n = 26). Expression of molecule PD-L1 on mast cells by gating on CD45⁺CD117⁺FcεRI⁺ cells. Color histograms represent staining of PD-L1; black, isotype control. Tumor-infiltrating PD-L1⁺tryptase⁺ mast cells were defined by immunofluorescence staining. Green, Tryptase; red, PD-L1; and blue, DAPI-stained nuclei. Scale bars: 50 μm. b Expression of PD-L1 on hCBMCs exposed to 50% autologous TTCS and NTCS for 24 h, or exposed to 50% TTCS for 6, 12, 24 h, or exposed to 20, 40, 80% TTCS for 24 h. black, isotype control. c Clustering of microarray data for the expression of 40 pro-inflammatory cytokine genes in human tumor tissues from 8 GC patients. d Expression of PD-L1 on hCBMCs exposed to TNF-α for 24 h. black, isotype control. e TNF-α concentration between autologous tumor and non-tumor tissues (n = 24) or between autologous TTCS and NTCS (n = 8) was analyzed. f The correlations between TNF-α and PD-L1⁺ mast cells in human tumors were analyzed. Results are expressed as the number of PD-L1⁺ mast cells per million total cells and TNF-α concentration in tumor tissues. g Expression of PD-L1 on hCBMCs exposed to TTCS with anti-TNF-α antibody for 24 h. Each ring or dot in panels a and f represents 1 patient. *, P < 0.05, **, P < 0.01 for groups connected by horizontal lines