Figure 1.

VECs express PD-L1 and CD80, but not PD-1. A: We isolated mRNA from MS1 cells, and primary VECs from heart (HEC) and lung (LEC) in vitro. The mRNA expression levels of PD-L1, CD80, and PD-1 in these three types of VECs were tested by real-time reverse transcription-polymerase chain reaction and represented as mRNA copies per 10⁶ copies of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression. B: The protein expression levels of PD-L1 and CD80 in these cells were detected by flow cytometry after staining with anti–PD-L1-FITC or anti–CD80-FITC. Isotype control is shown as a gray area.