Immune effector cell cytotoxic receptors (NCRs/Activating Receptors)

Immune effector cell cytotoxic receptors represent a functional class of surface proteins found on cells such as Natural Killer (NK) cells and cytotoxic T lymphocytes that, upon ligation, trigger the direct killing of target cells. This group includes the natural cytotoxicity receptors (NCRs) like NKp30, NKp44, and NKp46, as well as NKG2D and the low-affinity Fc receptor CD16. In a physiological context, these receptors recognize ligands associated with viral infection, cellular stress, or malignant transformation, initiating the release of cytotoxic granules containing perforin and granzymes. In modern oncology, these receptors are primary targets for therapeutic intervention; bispecific antibodies (e.g., BiTEs) and chimeric antigen receptor (CAR) therapies are designed to cross-link these receptors with tumor-associated antigens to bypass traditional MHC-restriction and force immune-mediated tumor lysis. While highly effective, therapeutic activation of these receptors carries risks of systemic inflammatory responses, such as cytokine release syndrome.

Other names

Natural cytotoxicity receptorsActivating NK cell receptorsCytotoxic immune receptorsImmune effector cell activating receptors

Engagement of these receptors via bispecific antibodies or CAR-T cells triggers the release of perforin and granzymes from effector cells (NK cells or T cells), leading to the lysis of target (tumor) cells.