Killer Cell Immunoglobulin-like Receptor (KIR)

Killer cell immunoglobulin-like receptors (KIRs) are a family of type I transmembrane glycoproteins primarily expressed on natural killer (NK) cells and some T lymphocytes. KIRs regulate NK cell activity by interacting with MHC class I molecules (HLA class I alleles) on target cells. They can be inhibitory or activating, allowing NK cells to distinguish between healthy self-cells and abnormal targets. KIR genes are highly polymorphic, contributing to diverse immune responses. KIRs play roles in immunity, tumor surveillance, autoimmunity, pregnancy, and transplantation.

Modulation of NK/T-cell activity via interaction with HLA class I molecules; inhibition or activation of cytotoxic responses.