• Purity

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

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Meassure by its ability to enhance anti-CD3-induced IFN-gamma secretion of mouse CD3    ⁺ T cells. The ED    ₅₀ for this effect is 0.4-2 μg/mL.

• Source

  Mouse myeloma cell line, NS0-derived Ala20-Pro223, with a C-terminal 6-His tag

• Accession #

• N-terminal Sequence    
  Analysis

  Ala20

• Predicted Molecular Mass

  23.7 kDa

• SDS-PAGE

  35-41 kDa, reducing conditions

Background: CD84/SLAMF5

CD84, also known as Ly‑9B and SLAMF5, is a type I transmembrane protein in the SLAM subgroup of the CD2 family. SLAM family proteins regulate multiple aspects of immune system function (1). Mature mouse CD84 consists of a 200 amino acid (aa) extracellular domain (ECD) with two Ig‑like domains, a 21 aa transmembrane segment, and a 87 aa cytoplasmic domain with two immunoreceptor tyrosine‑based switch motifs (ITSMs) (2). Alternate splicing generates an additional isoform that is truncated following the first Ig‑like domain. CD84 exhibits homophilic binding which is mediated by the N‑terminal Ig‑like domain (3). Ligation induces tyrosine phosphorylation in the cytoplasmic ITSMs which then recruit the signaling adaptor molecules SAP (SLAM‑associated protein) and EAT‑2 (EWS/Fli1‑activated transcript 2) (4, 5). CD84 is expressed as a 60‑90 kDa molecule with extensive and cell type‑specific glycosylation (6‑8). It is widely expressed among hematopoietic cells including hematopoietic stem cells (8), myeloid cells (  e.g. macrophages, monocytes, dendritic cells, granulocytes, and mast cells) (4, 7‑10), platelets and megakaryocytes (3, 7, 8, 11), and lymphocytes. Within the T cell lineage, CD84 is expressed on thymocytes, CD4  ^-CD8  ^- cells, single positive CD4 or CD8 cells, NKT cells, and on mouse but not human NK cells (3, 4, 8, 9, 12). Within the B cell lineage, it is expressed on pro‑ and pre‑, mature, marginal zone, and memory B cells as well as plasma cells (4, 8, 13). CD84 signaling inhibits Fc epsilon RI-induced mast cell activation (10) but enhances platelet activation (11), LPS‑induced macrophage activation (8), T cell proliferation and IFN‑ gamma production (3, 5), and the interactions between T cells and B cells that are required for germinal center formation (14).

• References:

1. Cannons, J.L. et al. (2011) Annu. Rev. Immunol.  29:665.

2. de la Fuente, M.A. et al. (1999) Immunogenetics 49:249.

3. Martin, M. et al. (2000) J. Immunol. 167:3668.

4. Tangye, S.G. et al. (2002) Eur. J. Immunol. 32:1640.

5. Tangye, S.G. et al. (2003) J. Immunol. 171:2485.

6. de la Fuente, M.A. et al. (1997) Blood. 90:2398.

7. Krause, S.W. et al. (2000) Biochem. J. 346:729.

8. Sintes, J. et al. (2010) J. Leukoc. Biol. 88:687.

9. Romero, X. et al. (2004) Tissue Antigens 64:132.

10. Alvarez-Errico, D. et al. (2011) J. Immunol. 187:5577.

11. Nanda, N. et al. (2005) Blood 106:3028.

12. Wang, N. et al. (2010) J. Immunol. 185:5683.

13. De Salort, J. et al. (2011) Immunol. Lett. 134:129.

14. Cannons, J.L. et al. (2010) Immunity 32:253.

• Long Name:

  SLAM Family Member 5

• Entrez Gene IDs:

  8832 (Human)

• Alternate Names:

  CD84 antigen (leukocyte antigen); CD84 antigen; CD84 molecule; CD84; Cell surface antigen MAX.3; DKFZp781E2378; hCD84; hly9-beta; leucocyte differentiation antigen CD84; leukocyte antigen CD84; Leukocyte differentiation antigen CD84; Ly-9B; mCD84; Signaling lymphocytic activation molecule 5; SLAM family member 5; SLAMF5; SLAMF5LY9B