Fig. 7

Inhibitory neutrophils induce T lymphocytes trans-differentiation and immunosuppression via PD-L1 pathway. a PD-L1 was knocked out (KO) in C57BL/6 mice. Expression of PD-L1 was detected by PCR. b LPS-stimulated wild type and PD-L1^−/− neutrophils for 12 h, and the expression of PD-L1 was detected by western blot. c Survival rate of wild type and PD-L1^−/− mice with sepsis. Sepsis was induced by CLP. Sixteen mice per group. d Effect of neutrophils on lymphocytes’ trans-differentiation. Lymphocytes co-culture with neutrophils in 4 days, neutrophils were stimulated with LPS (1 μg/mL) in 4 h. The results of transwell (TW) insert co-culture model were also observed (n = 4). e Effect of PD-L1-deficient LPS-stimulated neutrophils on lymphocytes’ trans-differentiation. Lymphocytes co-culture with neutrophils in 4 days, WT and PD-L1^−/− neutrophils were stimulated with LPS (1 μg/mL) in 4 h. The CD4, CD25 and FOXP3 were observed (n = 4). f–g Effect of PD-L1-deficient and LPS-stimulated neutrophils on lymphocytes’ activation and apoptosis (n = 5). Cell intervention and culture methods were consistent with d. *p < 0.05, **p < 0.01