Kir

KIR is the acronym for "killer-cell immunoglobulin-like receptor". KIR belongs to the family of anti-inflammatory immune checkpoints (ICs). Anti-inflammatory immune checkpoints inhibit the immune reactivity of T lymphocytes, in contrast to proinflammatory ICs, which increase the immune reactivity of T lymphocytes. Immune checkpoints are activated by cytokines (ligands) that are presented and released by other cells.

The "killer cell immunoglobulin-like receptors" are receptors that are mainly detectable in the cell membranes of natural killer cells (NK cells). Through KIR, the NK cell is able to recognize pathogenic cells, such as tumor cells or cells infected by microorganisms. This is done with the help of so-called short peptides that are expressed on the cell surface of these cells and to which KIR can bind. KIRis not limited to NK cells, but is also found on subpopulations of cytotoxic T lymphocytes.

The coding "KIR genes" form a gene family (in humans, 14 KIR genes are known to date) located on human chromosome 19 (gene locus 19q13.4), which belongs to the immunoglobulin superfamily.