CD274 and Sepsis: In various pre-clinical studies employing different rodent models of sepsis such as cecal ligation and puncture (CLP) and burn wound infection with Pseudomonas aeruginosa, PD-1 expression has been shown to be upregulated on T cells and PD-L1 expression was increased on innate immune cells including monocytes, dendritic cells, Kuppfer cells and neutrophils [17,21,35,36,37,38,39,40,41].