• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to inhibit anti-KIR2DL4 antibody induced IFN-gamma secretion by NK‑92 human natural killer lymphoma cells. The ED    ₅₀ for this effect is 0.3-1 µg/mL in the presence of 1 µg/mL of immobilized mouse anti-hKIR2DL4 antibody (Catalog # MAB2238).

• Source

  Mouse myeloma cell line, NS0-derived

  Human KIR2DL4 (His24 - His242) Accession # Q99706	IEGRMD	Human IgG1 (Pro100 - Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  His24

• Predicted Molecular Mass

  24.4 kDa (monomer)

• SDS-PAGE

  65 kDa, reducing conditions

Background: KIR2DL4/CD158d

KIR2DL4 (also known as 2DL4, p49, CD158d, KIR103) is a type I transmembrane protein of the killer cell Ig-like receptor (KIR) family expressed on NK and subsets of gamma δT and memory/effector alpha beta T cells. KIR2DL4 is a unique KIR (1 - 3); alleles are not clonally restricted but are expressed codominantly (4) in all activated NK cells and constitutively on CD56^hi NK cells. KIR members with two Ig-like domains (2D) usually express domains D1 and D2, but KIR2DL4 expresses D0 and D2. Other long-tailed (L) KIR have two cytoplasmic inhibitory signaling domains (ITIM), but KIR2DL4 has one ITIM and also exhibits characteristics of activating KIR (2). An arginine within the transmembrane sequence of KIR2DL4 interacts with the signaling molecule Fc epsilon RI-gamma, while in activating KIR, a transmembrane lysine interacts with DAP12 (1, 5). The KIR2DL4 gene is highly polymorphic. Seven splice variants missing one or more exons have been identified, but it is not clear whether these are expressed. Several of the nine alleles identified encode a frameshift creating a prematurely truncated protein. It is estimated that up to 25% of humans do not express KIR2DL4 capable of reaching the cell surface (1, 7, 10). Human KIR2DL4 is 65 - 83% amino acid identical to other primates. KIR receptors have no structural orthologs in non-primates, although mouse Ly49 proteins are functional orthologs. Cross-linking of KIR2DL4 induces NK cells to produce IFN-gamma (6, 7); stimulation with IL-2 upregulates cell surface expression on CD56^dim cells and allows cytotoxicity (7). Although a role in immune privilege of the fetus has been suggested due to reported recognition of fetal trophoblast HLA-G by KIR2DL4 in the maternal decidua (11), subsequent data have not supported this recognition (1, 9).

• References:

1. Lanier, L.L. (2005) Annu. Rev. Immunol. 23:225.

2. Faure, M. and E.O. Long (2002) J. Immunol. 168:6208.

3. Selvakumar, A. et al. (1996) Tissue Antigens 48:285.

4. Chan, H.-W. et al. (2003) J. Exp. Med. 197:245.

5. Kikuchi-Maki, A. et al. (2005) J. Immunol. 174:3859.

6. Rajagopalan, S. et al. (2001) J. Immunol. 167:1877.

7. Kikuchi-Maki, A. et al. (2003) J. Immunol. 171:3415.

8. Gedil, M.A. et al. (2005) Tissue Antigens 65:402.

9. Witt, C.S. et al. (2002) Eur. J. Immunol. 32:18.

10. Goodridge, J.P. et al. (2003) J. Immunol. 171:1768.

11. Ponte, M. et al. (1999) Proc. Natl. Acad. Sci. USA 96:5674.

• Long Name:

  Killer Cell Immunoglobulin-like Receptor, Two Domain Long Cytoplasmic Tail, 4

• Entrez Gene IDs:

  3805 (Human)

• Alternate Names:

  103AS; 15.212; CD158 antigen-like family member D; CD158d antigen; CD158d; CD158DKIR103ASKiller cell inhibitory receptor 103AS; G9P; killer cell immunoglobulin-like receptor 2DL4; killer cell immunoglobulin-like receptor, two domains, long cytoplasmic tail, 4; killer Ig receptor; KIR103; KIR-103AS; KIR2DL4; MHC class I NK cell receptor KIR103AS; natural killer cell inhibitory receptor; NK cell receptor