Figures & data
Figure 1. (A) CTLA4 expressed on tumor-specific T cell shows higher affinity for binding to CD80/CD86 ligands expressed on DC than CD28. The CTLA4/CD80/CD86 interaction inhibits T-cell activation. PD1 is also expressed on tumor-specific T cells and binds to PD-L1 ligand expressed on DC. The PD1/PD-L1 interaction inhibits T-cell activation. (B) Use of anti-CTLA4 and anti-PD1 Mabs to block immune checkpoints: CTLA4 is blocked by anti-CTLA4 and CD80/CD86 is released to bind with CD28. CD28/CD80/CD86 interaction activates T cell. PD1 is blocked by anti-PD1 and inhibition of PD1 checkpoint activates T cell. (C) PD1 is expressed on the surface of T cell after activation and binds to PD-L1 ligand expressed by tumor cell. The PD1/PD-L1 interaction inhibits the cytotoxic activity of T cell against the tumor cell. (D) Use of anti-PD1 MAb blocks the binding of PD1 to the ligand PD-L1. PD1/PD-L1 checkpoint blockade results in activation of T-cell cytotoxicity.
