Figure 2

Sepsis increases PD-L1 expression in the mouse intestine. C57BL/6 mice were subjected to sham or CLP. Twenty-four hours after surgery, PD-L1 protein levels in the ileum and colon tissue homogenates were determined by Western blot analyses and semiquantitated by densitometry expressed as integrated density (IDT) values of target protein versus IDT values of β-actin. (A) CLP induces a significant increase in PD-L1 protein expression in the ileum and colon tissues. Time course of rising gene and protein expression in intestinal epithelial cells (IECs) after CLP. IECs of the small intestine were isolated at 6, 24 and 48 h after surgery for PD-L1 expression analysis. (B) PD-L1 mRNA is significantly increased in the IECs at 6, 24 and 48 h post-CLP compared with sham IECs. (C) While not changed at 6 h, PD-L1 protein expression is markedly elevated by 24 and 48 h post-CLP. Significance indicated by * P < 0.05 versus sham; rank sum test, mean ± standard error of the mean (SEM); n = 4–8 mice/group.