Immune checkpoint: PD1 binding to PD-L1 - Stock-Fotografie

Programmed cell death protein 1 (PD-1) and its ligand PD-L1 belong to the family of immune checkpoint proteins that act as co-inhibitory factors, which can halt or limit the development of the T cell response. When PD-L1 binds to PD-1, an inhibitory signal is transmitted into the T cell, which reduces cytokine production and suppresses T-cell proliferation. PD1/PD-L1 interaction ensures that the immune system is activated only at the appropriate time in order to minimize the possibility of chronic autoimmune inflammation. Tumor cells exploit this immune-checkpoint pathway as a mechanism to evade detection and inhibit the immune response.