• Purity

  >90%, 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 the ability of the immobilized protein to induce IFN-gamma secretion in NK‑92 human natural killer lymphoma cells. The ED    ₅₀ for this effect is 3-15 μg/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human CD72 (Arg117-Asp359) Accession # P21854	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Arg117

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  54.6 kDa (monomer)

• SDS-PAGE

  60-65 kDa, reducing conditions

Background: CD72

CD72, also known as Lyb‑2, is a 40‑45 kDa type II transmembrane glycoprotein that plays a role in immune system regulation (1). Mature human CD72 consists of a 95 amino acid (aa) cytoplasmic domain with two immunoreceptor tyrosine‑based inhibitory motifs (ITIMs), a 21 aa transmembrane segment, and a 243 aa extracellular domain with a coiled‑coil domain and a C‑type lectin domain (2). Within the ECD, human CD72 shares 48% and 44% aa sequence identity with mouse and rat CD72, respectively. CD72 is expressed on B lineage cells, NK cells, monocytes, dendritic cells, and mast cells (2‑6). CD72 binds to CD5 with mouse/human cross‑reactivity and to Semaphorin 4D/CD100 (5, 7‑9). It associates with CD79A in the B cell antigen receptor (BCR) complex following antigen stimulation and dampens BCR signaling through interactions with the phosphatase SHP‑1 (10). CD72 ligation with antibodies or with Semaphorin 4D induces tyrosine dephosphorylation of the CD72 cytoplasmic domain and its dissociation from SHP‑1, leading to B cell proliferation (5, 9). Both CD72 and Semaphorin 4D are required for the maintenance of B cell anergy and the regulation of peripheral B cell tolerance as shown by the development of autoimmunity in mice that lack either molecule (10, 11). In addition to its negative regulation of BCR signaling, CD72 can induce positive signaling in B cells independent of the BCR (12). CD72 binding to Semaphorin 4D induces cytokine production by monocytes and dendritic cells, inhibits SCF R/c‑kit induced mast cell proliferation and activation, and inhibits the cytolytic activity of NK cells (4‑6). Semaphorin 4D is expressed on activated NK cells and contributes to the adhesive interaction between NK and CD72  ⁺ target cells leading to a more efficent killing and enhanced IFN-gamma secretion (13).

• References:

1. Nykimbeng-Takwi, E. and S.P. Chapoval (2011) Immunol. Res. 50:10.

2. Von Hoegen, I. et al. (1990) J. Immunol. 144:4870.

3. Nakayama, E. et al. (1989) Proc. Natl. Acad. Sci. 86:1352.

4. Alcon, V.L. et al. (2009) Eur. J. Immunol. 39:826.

5. Ishida, I. et al. (2003) Int. Immunol. 15:1027.

6. Kataoka, T.R. et al. (2010) J. Immunol. 184:2468.

7. Van de Velde, H. et al. (1991) Nature 351:662.

8. Luo, W. et al. (1992) J. Immunol. 148:1630.

9. Kumanogoh, A. et al. (2000) Immunity 13:621.

10. Kumanogoh, A. et al. (2005) Int. Immunol. 17:1277.

11. Li, D. H.-H. et al. (2008) Arthritis Rheum. 58:3192.

12. Wu, H.-J. et al. (2001) J. Immunol. 167:1263.

13. Mizrahi, S. et al. (2007) PLoS ONE 9:e818.

• Entrez Gene IDs:

  971 (Human); 12517 (Mouse)

• Alternate Names:

  CD72 antigenB-cell differentiation antigen CD72; CD72 molecule; CD72; CD72b; Ly-19.2; Ly-32.2; Lyb-2; LYB2lyb-2