• 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 in a cell proliferation assay using anti-IgM stimulated mouse B cells.

  The ED₅₀ for this effect is 0.2-1.2 ng/mL.

• Source

  Chinese Hamster Ovary cell line, CHO-derived Ala134-Leu285

• Accession #

• N-terminal Sequence    
  Analysis

  Ala134

• Structure / Form

  High Molecular Weight Multimer

• Predicted Molecular Mass

  17.0 kDa (monomer)

• SDS-PAGE

  19 kDa, reducing conditions

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: BAFF/BLyS/TNFSF13B

B-cell activating factor (BAFF), also known as BLyS, TALL-1, THANK, and TNFSF13B, is a 32 kDa transmembrane glycoprotein in the TNF ligand superfamily. It is involved in multiple aspects of immune system regulation, particularly towards B cells (1, 2). Mature human BAFF consists of a 46 amino acid (aa) cytoplasmic domain, a 21 aa transmembrane segment, and a 218 aa extracellular domain (ECD) with a stalk region and one TNF-like domain (3, 4). Within aa 134-285 of the ECD, human BAFF shares 72% aa sequence identity with mouse BAFF. It can be expressed as a homo-oligomer or as a heteromer in association with the related TNFSF member APRIL (4, 5). A 18 kDa fragment containing the TNF-like domain can be released by proteolysis between Arg133 and Ala134 (4). Soluble BAFF is stored intracellularly in neutrophils and released upon inflammatory stimulation (6). Alternative splicing generates an isoform termed deltaBAFF that lacks 19 aa between the proteolytic cleavage site and the TNF-like domain. deltaBAFF can form heteromers with BAFF and negatively regulates BAFF function (7). BAFF is produced by many hematopoietic cell types including monocytes, macrophages, neutrophils, dendritic cells, and T cells and also by adipocytes (1, 2, 8). Both BAFF and APRIL are functional ligands for the TNF receptor superfamily members BCMA and TACI, and BAFF additionally binds and signals through BAFF R (9, 10). All three receptors are primarily expressed by B cells (10). BAFF plays a critical role in the development and survival of B lineage cells (2, 11, 12). Mice that overexpress BAFF exhibit elevated B cell numbers, increased formation and size of germinal centers, and symptoms of autoimmunity (13). Soluble BAFF is elevated in B cell malignancies, autoimmunity, and other immune disorders (1). In addition, BAFF co‑stimulates T cell activation, promotes a Th1 biased immune response, and promotes the expansion of Treg cells (14‑16). BAFF also promotes monocyte survival, proinflammatory cytokine secretion, and differentiation to macrophages (17).

• References:

1. Lied, G.A. and A. Berstad (2011) Scand. J. Immunol. 73:1.

2. Mackay, F. et al. (2010) Immunol. Rev. 237:205.

3. Moore, P.A. et al. (1999) Science 285:260.

4. Schneider, P. et al. (1999) J. Exp. Med. 189:1747.

5. Roschke, V. et al. (2002) J. Immunol. 169:4314.

6. Scapini, P. et al. (2003) J. Exp. Med. 197:297.

7. Gavin, A.L. et al. (2003) J. Biol. Chem. 278:38220.

8. Alexaki, V.-I. et al. (2009) J. Immunol. 183:5948.

9. Yu, G. et al. (2000) Nat. Immunol. 1:252.

10. Thompson, J.S. et al. (2001) Science 293:2108.

11. Schiemann, B. et al. (2001) Science 293:2111.

12. Litinskiy, M.B. et al. (2002) Nat. Immunol. 3:822.

13. Batten, M. et al. (2000) J. Exp. Med. 192:1453.

14. Huard, B. et al. (2001) J. Immunol. 167:6225.

15. Sutherland, A.P.R. et al. (2005) J. Immunol. 174:5537.

16. Walters, S. et al. (2009) J. Immunol. 182:793.

17. Chang, S.K. et al. (2006) Blood 108:2687.

• Long Name:

  B cell Activating Factor

• Entrez Gene IDs:

  10673 (Human); 24099 (Mouse); 498666 (Rat)

• Alternate Names:

  ApoL related ligand TALL-1; B lymphocyte stimulator; BAFF; BAFFB-cell activating factor; B-cell-activating factor; BLyS; BLYSB-lymphocyte stimulator; CD257 antigen; CD257; Dendritic cell-derived TNF-like molecule; DTL; TALL1; TALL-1delta BAFF; TALL1Delta4 BAFF; THANK; TNF- and APOL-related leukocyte expressed ligand 1; TNF and ApoL-related leukocyte expressed ligand 1; TNF homolog that activates apoptosis; TNFSF13B; TNFSF20; tumor necrosis factor (ligand) superfamily, member 13b; tumor necrosis factor (ligand) superfamily, member 20; tumor necrosis factor ligand superfamily member 13B; tumor necrosis factor superfamily, member 13b; tumor necrosis factor-like protein ZTNF4; ZTNF4