Fig. 3
From: Fibrinogen-like protein 1 (FGL1): the next immune checkpoint target
Classic and novel immune checkpoints between tumor cells and immune cells. The traditional marker PD-L1 (B7-H1/CD274), expressed on the surface of tumor cells, binds to PD-1 on the T cell surface, while the newly identified molecule FGL1 binds to another inhibitory receptor, LAG3, which has other ligands, such as MHC II, galectin-3 and LSECtin (degree of affinity: thick line > thin line > dashed line). In addition, CD80 and CD86 (B7) on the surface of APCs bind with CD28 or CTLA-4 to provide auxiliary stimulatory and suppressive signals, respectively