• 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 bind fluorescein-conjugated     S. aureus Bioparticles. Jiang, Y.     et al. (2006) J. Biol. Chem.     281:11834. The ED    ₅₀ for this effect is 0.4-2 µg/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human LILRB3/CD85a/ILT5 (Gly24-Glu443)  Accession # AAB68668	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Gly24

• Structure / Form

  Disulfide linked homodimer

• Predicted Molecular Mass

  72.6 kDa (monomer)

• SDS-PAGE

  95-105 kDa, reducing conditions

Background: LILRB3/CD85a/ILT5

Leukocyte immunoglobulin-like receptor subfamily B (LILRB3), also known as ILT5, LIR3, and CD85a, is an immunoglobulin superfamily member that is involved in immune regulation. Subfamily B members have cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs) that inhibit signaling events via phosphatase SHP-1. Subfamily A members are activating receptors that lack ITIMs and signal through association with FcR gamma (1, 2). Mature LILRB3 is a highly polymorphic  
85-95 kDa glycoprotein that consists of a 420 amino acid (aa) extracellular domain (ECD) with four Ig-like domains, a 21 aa transmembrane segment, and a 167 aa cytoplasmic domain with three ITIMs (3). Alternative splicing generates an isoform with a 17 aa insertion in the juxtamembrane ECD. In mouse and rat, the LILRB3 gene encodes the PIR-B protein which has six Ig-like domains. Rodent PIR-B and human LILRB3 share 55% aa sequence identity within common regions of their ECDs. LILRB3 is expressed on the surface of peripheral monocytes, neutrophils, eosinophils, basophils, and mast cell progenitors (4-6). Triggering of LILRB3 inhibits the activation of macrophages, mast cells, neutrophils, basophils, and B cells (5, 7). On osteoclast precursors, LILRB3 ligation inhibits RANK L/TRANCE or M-CSF induced differentiation (8). LILRB3 can also bind to ligands exposed on necrotic tumor cells (9). Both PIR-B and LILRB3 are receptors for S. aureus, and activation of these receptors by bacteria influences the innate immune response triggered by TLRs (3). R&D Systems in-house testing indicates that LILRB3 binds to  
Angiopoietin-like 7, consistent with the demonstrated functional interactions between other members of these protein families (10). In the mouse CNS, PIR-B functions as a receptor for the myelin proteins Nogo, MAG, and OMgp and mediates their inhibitory action on neurite outgrowth and axon regeneration (11). Upon binding to MAG, PIR-B associates with TrkB and NGF R/p75 in cerebellar granule neurons (12).

• References:

1. Thomas, R. et al. (2010) Clin. Rev. Allergy Immunol. 38:159.

2. Anderson, K.J. and R.L. Allen (2009) Immunology 127:8.

3. Nakayama, M. et al. (2007) J. Immunol. 178:4250.

4. Tedla, N. et al. (2003) Proc. Natl. Acad. Sci. USA 100:1174.

5. Sloane, D.E. et al. (2004) Blood 104:2832.

6. Tedla, N. et al. (2008) J. Leukoc. Biol. 83:334.

7. Uehara, T. et al. (2001) J. Clin. Invest. 108:1041.

8. Mori, Y. et al. (2008) J. Immunol. 181:4742.

9. Jones, D.C. et al. (2016) Oncotarget PMID 26769854.

10. Zheng, J. et al. (2012) Nature 485:656.

11. Atwal, J.K. et al. (2008) Science 322:967.

12. Fujita, Y. et al. (2011) Cell Death Dis. 2:e198.

• Entrez Gene IDs:

  11025 (Human)

• Alternate Names:

  CD85 antigen-like family member A; CD85a antigen; CD85a; HL9Immunoglobulin-like transcript 5; ILT5; ILT-5; ILT5CD85a; Leukocyte immunoglobulin-like receptor 3; leukocyte immunoglobulin-like receptor subfamily B member 3; leukocyte immunoglobulin-like receptor, subfamily B (with TM and ITIM domains); LILRB3; LIR3; LIR3CD85A; LIR-3MGC138403; member 3; Monocyte inhibitory receptor HL9; PIRB