• Purity

  >97%, 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

  Measured in a cell proliferation assay using PHA-activated human peripheral blood lymphocytes (PBL). Yokota, T.     et al. (1986) Proc. Natl. Acad. Sci. USA     83:5894. The ED    ₅₀ for this effect is 0.1-0.5 ng/mL.    
  The specific activity of Recombinant Human IL-7 is approximately 4.4 x 10    ⁵ IU/μg, which is calibrated against human IL-7 WHO International Standard (NIBSC code: 90/530).    
   

• Source

  E. coli-derived Asp26-His177, with an N-terminal Met

• Accession #

• N-terminal Sequence    
  Analysis

  Met

• Predicted Molecular Mass

  17 kDa

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: IL-7

IL-7 (interleukin-7) is a 25 kDa cytokine of the hemopoietin family that plays important roles in lymphocyte differentiation, proliferation, and survival (1‑4). Human
IL‑7 cDNA encodes 177 amino acids (aa) that include a 25 aa signal peptide (3). Human IL-7 shares approximately 60-63% aa sequence identity with mouse, rat, canine and feline IL-7, and 72-76% with equine, bovine, ovine, porcine, feline and canine IL-7.  Human and mouse IL-7 exhibit cross-species activity (2, 3). IL-7 is produced by a wide variety of cells in primary and secondary lymphoid tissues, including stromal epithelial cells of the thymus, bone marrow, and intestines (1, 2, 5). Circulating IL-7 is limiting in healthy animals, but increases during lymphopenia (1, 6). IL-7 signals through a complex of the IL-7 Receptor alpha subunit (IL-7 R alpha, also known as CD127) with the common gamma chain ( gamma _c) (1). The gamma _c is also a subunit of the receptors for IL-2, -4, -9, -15, and -21 (1). IL-7 R alpha is expressed on double negative (CD4^-CD8^-) and CD4⁺ or CD8⁺ single positive naïve and memory T cells, but undergoes IL-7-mediated down‑regulation and shedding during antigen-driven T cell proliferation, and is absent on regulatory T cells (1, 2, 6-11). IL-7 contributes to the maintenance of all naïve and memory T cells, mainly by promoting expression of the anti-apoptotic protein Bcl-2 (9-11). It is required for optimal T cell-dendritic cell interaction (6). IL-7 is expressed early in B cell development prior to the appearance of surface IgM (1, 5, 9). In mouse, IL-7 activation of IL-7 R alpha is critical for both T cell and B cell lineage development, while in humans, it is required for T cell but not for B cell development (4, 9, 12, 13). However, IL-7 functions in both mouse and human pro-B cells to suppress premature Ig light chain recombination during proliferative growth (14, 15).

• References:

1. Sasson, S.C. et al. (2006) Curr. Drug Targets 7:1571.

2. Barata, J.T. et al. (2006) Exp. Hematol. 34:1133.

3. Goodwin, R.G. et al. (1990) Proc. Natl. Acad. Sci. USA 86:302.

4. Namen, A.E. et al. (1988) Nature 333:571.

5. Shalapour, S. et al. (2012) PLoS ONE 7: e31939.

6. Saini, M. et al. (2009) Blood 113:5793.

7. Park, J.H. et al. (2004) Immunity 21:289.

8. Vranjkovic, A. et al. (2007) Int. Immunol. 19:1329.

9. Sudo, T. et al. (1993) Proc. Natl. Acad. Sci. 90:9125.

10. Seddon, B. et al. (2003) Nat. Immunol. 4:680.

11. Schluns, K.S. et al. (2000) Nat. Immunol. 5:426.

12. Peschon, J.J. et al. (1994) J. Exp. Med. 180:1955.

13. Pribyl, J.A. and T.W. LeBien (1996) Proc. Natl. Acad. Sci. 93:10348.

14. Johnson, K. et al. (2012) J. Immunol. 188:6084.

15. Nodland, S.E. et al. (2011) Blood 118:2116.

• Long Name:

  Interleukin 7

• Entrez Gene IDs:

  3574 (Human); 16196 (Mouse); 25647 (Rat)

• Alternate Names:

  IL7; IL-7; IL-7interleukin-7; interleukin 7; Lymphopoietin-1; PBGF