programmed death-1
Also written as: PD-1 — programmed death-1
An immune checkpoint receptor on T cells that inhibits immune responses when activated.
Full Definition
Programmed death-1 (PD-1) is a cell surface receptor found on activated T cells, B cells, and natural killer cells that serves as an immune checkpoint protein. When PD-1 binds to its ligands (PD-L1 or PD-L2), it sends an inhibitory signal that suppresses T-cell activation and proliferation, effectively putting the brakes on immune responses. In cancer, tumor cells often exploit this pathway to evade immune detection. PD-1 inhibitors, such as pembrolizumab and nivolumab, block this interaction to enhance anti-tumor immunity and have revolutionized cancer treatment across multiple tumor types.
Usage
Usage note: Spell out on first use, then use PD-1. Note the hyphen in both full form and abbreviation.
In Context
- "The patient showed excellent response to PD-1 blockade therapy." — Clinical progress note
- "Programmed death-1 expression was evaluated by immunohistochemistry." — Laboratory report