Figure 1.

Comparison of structures of PD-1 in complex with nivolumab-Fab (A) (PDB code: 5WT9), pembrolizumab-Fab (B) (PDB code: 5JXE) and toripalimab-Fab (C) (PDB code: 6JBT). L chain, light chain; H chain, heavy chain; LCDRs, complementary determining regions of the light chain; HCDRs, complementary determining regions of the heavy chain; PD-1, programmed death protein 1. Images were acquired from Protein Data Bank and relevant research was conducted by Tan S et al., Na Z et al., and Liu H et al., respectively (12–16).