PD-1 (programmed cell death-1)

The receptor in the PD-1 checkpoint pathway that sends negative signals to the T-cell when it connects to a PD-1 or PD-2 ligand (PD-L1 or PD-L2). These negative signals normally slow down or stop the immune response when it’s no longer necessary. Certain cancer cells can influence the engagement of this checkpoint, which puts the brakes on the immune response. [Patient Resource LLC]