KIR2DS4, Fc Chimera, Recombinant, Human (Killer Cell Immunoglobulin-Like Receptor 2DS4, CD158 Antige

KIR2DS4 (2DS4), previously called NKAT-8 and designated CD158i, is a type I transmembrane glycoprotein that belongs to the killer cell Ig-like receptor (KIR) family. KIRs are expressed on CD56dim NK cells and T cell subsets where they differentiate normal from abnormal cells and regulate effector functions in the innate immune system. KIRs are named for the number of Ig-like domains (2D or 3D) in the extracellular domain (ECD), and whether they have long or short (L, S) cytoplasmic tails. KIR2DS4 cDNA encodes 304aa including a 21aa signal sequence, a 224aa ECD, a 20aa transmembrane sequence and a 39aa cytoplasmic domain. KIR receptors have no structural orthologs in nonprimates, although mouse 49aa proteins perform similar functions. Like other activating KIRs, KIR2DS4 has a short tail and a positively charged aa within the transmembrane domain that interacts with the ITAM-bearing signaling adaptor, DAP12. Expression of activating KIR is balanced with inhibitory KIR to impart specificity to the immune response. KIR2DS4 recognizes six HLA-C allotypes and two HLA-A allotypes (A*1101 and A*1102) but no HLA-B allotypes. It has also been suggested that KIR2DS4 recognizes a non-MHC ligand, based on specific binding to melanoma cells that lack MHC Class I. A common allele, KIR2DS4*003, is present in up to 89% of Caucasians and ~30% of Asians, it creates a prematurely terminated, soluble, inactive form. Lack of functional KIR2DS4 can potentially create unbalanced inhibition of killer cell function. Source: Recombinant corresponding to aa22-245 from human KIR2DS4 expressed in mouse Murine myeloma cell line, NS0. Molecular Weight: ~51.2kD, Biological Activity: Measured by its ability to bind BJAB human Burkitt's lymphoma cells in a flow cytometry assay. Endotoxin: ~1EU/1ug (LAL) , Storage and Stability:, Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 3 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.