Human Killer Cell Immunoglobulin-Like Receptor 2Dl1 (KIR2DL1) Protein

Background

Killer cell immunoglobulin-like receptors (KIRs) are a family of proteins primarily expressed on the surface of natural killer (NK) cells and some T-cell subsets, where they play a crucial role in the innate immune system. KIR2DL1, a member of this family, specifically recognizes certain human leukocyte antigen (HLA) class I molecules, allowing NK cells to monitor cellular health by detecting variations in HLA expression. KIR2DL1 is an inhibitory receptor, meaning that its engagement generally suppresses NK cell cytotoxic activity. The interaction between KIR2DL1 and HLA class I molecules is part of a broader system known as immune surveillance, where NK cells detect and respond to stress or infection signals on potential target cells, such as virally infected or transformed cells. KIRs are highly polymorphic and exhibit considerable variability among individuals. This diversity contributes to the versatility of NK cell responses, enhancing the immune system's adaptability. The genes encoding KIR proteins, including KIR2DL1, are located on chromosome 19q13.4 in the leukocyte receptor complex (LRC). KIR2DL1 recognizes HLA-C molecules, specifically those with the C2 epitope (HLA-C group 2), which consists of specific amino acid sequences.