• Purity

  >95%, by SDS-PAGE with silver staining

• Endotoxin Level

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

• Activity

  Measured by its ability to bind KG?1A human acute myelogenous leukemia cells in a flow cytometry assay. When 250 ng of Recombinant Human KIR2DL1/CD158a Fc Chimera is added to 1 x 10    ⁶ KG-1A cells, >55% of the cells will bind to the protein.

• Source

  Mouse myeloma cell line, NS0-derived

  Human KIR2DL1/CD158a (His22-Arg242) Accession # P43626	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  His22

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  51 kDa (monomer)

• SDS-PAGE

  72-80 kDa, reducing conditions

Background: KIR2DL1/CD158a

KIR2DL1 (2DL1, formerly NKAT1, designated CD158a) is a 348 amino acid (aa) type I transmembrane glycoprotein that belongs to the human killer cell Ig-like receptor (KIR) family (1, 2). KIRs are expressed on human CD56dim NK cells and T cell subsets, and regulate effector functions in the innate immune system (1-3). 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 (1-3). Individuals will express varying subsets of inhibiting and activating KIRs with varying polymorphisms (1, 4). Like other inhibiting KIRs, KIR2DL1 has two ITIM domains within its long tail that block activating receptor clustering (2, 5). Within the ECD, KIR2DL1 shares high aa sequence identity (92%) with KIR2DL2. KIR2DL1 targets Lys80-containing HLA-C2 allotypes while KIR2DL2 rather recognizes Ans80 containing HLA-C1 (1, 6-8). Three KIRs proteins together (2DL1-3) recognize and inhibit NK cytotoxicity against cells expressing any HLA-C allotype, allowing self-recognition, but also conferring susceptibility to leukemia (1-3). In primary human NK cell clones, KIR2DL1 regulates the level of MHC I proteins expression required for NK cell inhibition (9).

• References:

1. Purdy, A.K. and Campbell, K.S. (2009) Cancer Biol. Ther. 8:13.

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

3. Kulkarni, S. et al. (2008) Sem. Immunol. 20:343.

4. Middleton, D. and F. Gonzelez (2009) Immunology 129:8.

5. Abeyweera, T.P. et al. (2011) J. Cell Biol. 192:675.

6. Moesta, A.K. et al. (2008) J. Immunol. 180:3969.

7. Boyington, J.C. et al. (2000) Nature 405:537.

8. Snyder, G.A. et al. (1999) Proc. Natl. Acad. Sci. USA 96:3864.

9. Almeida, C.R. et al. (2011) PLoS ONE. 6:e24927.

• Long Name:

  Killer Cell Immunoglobulin-like Receptor, Two Domain Long Cytoplasmic Tail, 1

• Entrez Gene IDs:

  3802 (Human)

• Alternate Names:

  CD158 antigen-like family member A; CD158a antigen; CD158a; CD158Ankat1; cl-42; killer cell immunoglobulin-like receptor 2DL1; killer cell immunoglobulin-like receptor, two domains, long cytoplasmic tail, 1; killer Ig receptor; killer inhibitory receptor 2-2-1; KIR221; KIR2DL1; MHC class I NK cell receptor; Natural killer-associated transcript 1; NKAT; NKAT-1; NKAT1KIR-K64; p58 killer cell inhibitory receptor KIR-K64; p58 natural killer cell receptor clones CL-42/47.11; p58 NK cell inhibitory receptor NKR-K6,47.11; p58 NK receptor CL-42/47.11; p58.1 MHC class-I-specific NK receptor; p58.1