KIR2DL5 (2DL5, designated CD158f) is a 60kD 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 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. Like other inhibiting KIRs, KIR2DL5 has two ITIM domains within its long tail, however, one of these is atypical and may cause KIR2DL5 to be less inhibitory than most inhibiting KIRs. Gene duplication is thought to have resulted in individual genes coding for KIR2DL5 A and B proteins that vary by only 2aa. Individuals may express either KIR2DL5A or KIR2DL5B, both proteins, or neither protein. Within the KIR family, KIR2DL5 and KIR2DL4 form a subfamily. The two share 79% aa sequence identity, have longer cytoplasmic tails than other KIR, and each has one D0 and one D2-type Ig-like domain. However, KIR2DL5 is only inhibitory, while KIR2DL4 has characteristics of both activating and inhibiting KIR. Source: Recombinant corresponding to aa22-240 from human KIR2DL5 expressed in Murine myeloma cell line, NS0. Molecular Weight: ~50.1kD Biological Activity: Measured by its ability to bind HLA on MDA-MB-231 human breast adenocarcinoma cells (ATCC: HTB-26). The ED50 for this effect is typically 0.9-3.6ug/ml. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. 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.
