APC anti-human CD158d (KIR2DL4)

CD158 molecules, also known as KIRs (killer cell immunoglobulin-like receptors), are a family of transmembrane proteins with either two (KIR2D) or three (KIR3D) Ig-like extracellular domains. Some KIRs, with long cytoplasmic domains, contain ITIMs and possess inhibitory functions and others, with short cytoplasmic regions, lack ITIM and have activation functions. Fourteen polymorphic KIR genes have been reported in humans. KIR2DL4 (CD158d) is a unique receptor which has an ITIM in its cytoplasmic domain and a charged residue in the transmembrane domain. It possesses both inhibitory and activation functions. Two common alleles (10A and 9A) of KIR2DL4 have been reported. The 10A allele (with 10 adenines at the end of the transmembrane exon) receptor is expressed on CD56high NK subset, whereas its expression on CD56dim NK cells is inducible upon culture. The major 9A allele receptor is a secreted form. HLA-G is the ligand of CD158d.