Figure 2.

PD-1/PD-L1 checkpoint molecules regulate T cell activation. Upon peptide-MHC interaction with its T cell receptor in concurrence with costimulatory signals, T cells are activated, resulting in T cell-mediated killing and the release of cytokines, such as IFN-γ and TNFα. The interaction between PD-1 and PD-L1 results in the downregulation of anti-tumor T cell signaling. An agonistic anti-PD-(L)1 antibody will disrupt this interaction and subsequently help with T cell activation.