Fig. 1

Induction of T-cell activation by anti-PD-1 monoclonal antibody (mAb) is associated with altered MDSC function in patient-derived tumor organoids. a Illustration depicting patient-derived tumor organoid (PDO) cultures from colorectal cancer (CRC) tissues, PD-1 antibody (20 μg/mL), and IgG control antibody (20 μg/mL). b Representative flow cytometry and statistical analysis of the activation of infiltrated T lymphocytes in organoid CRC tissues after anti-PD-1 treatment. The data shown are from anti-PD-1 therapy-responsive samples (n = 5). c Quantification of MDSCs in CRC tissues after PD-1 blockade therapy. R indicates that patients responded to anti-PD-1 therapy (n = 5) and NR indicates that patients had no response to anti-PD-1 therapy (n = 8). d Summarized data of the proportion of PMN-MDSCs (CD45⁺Lin⁻HLA-DR^low/−CD33⁺CD11b⁺CD15⁺CD14⁻) and M-MDSCs (CD45⁺Lin⁻HLA-DR^low/−CD33⁺CD11b⁺CD15⁻CD14⁺) in CRC tissues. e Annexin V expression on MDSCs was determined using fluorescence-activated cell sorting (FACS) in CRC tissues. f Representative immunofluorescence staining and statistical analysis of ARG-1 expression in CD11b⁺ cells in situ in CRC tissues. The data shown in d–f are from anti-PD-1 therapy-responsive samples (n = 5). g, h Correlation between the number of TNF-α⁺IFN-γ⁺ T cells and the proportion of apoptotic MDSCs and ARG-1 expression in CD11b⁺ cells in fresh CRC tissues (n = 10). The scale bar indicates 50 μm. Act. T represents activated T cells. The data are shown as the mean ± SEM. *p < 0.05; **p < 0.01