Bcakground

Interleukin-13 (IL-13) is a monomeric 17 kDa immunoregulatory cytokine that plays a key role in the pathogenesis of allergy, cancer, and tissue fibrosis. It is secreted by several helper T cell subsets, NK cells, mast cells, eosinophils, basophils, and visceral smooth muscle cells (1-3). Mature human IL-13 shares approximately 58% amino acid sequence identity with mouse and rat IL-13. Despite the low homology, it exhibits cross-species activity between human, mouse, and rat (4). IL-13 suppresses the production of proinflammatory cytokines and other cytotoxic substances by macrophages, fibroblasts, and endothelial cells. On B cells, it promotes cellular activation, immunoglobulin class switching to IgE, and the up-regulation of CD23/Fc epsilon RII (1, 5). IL-13 binds with low affinity to the transmembrane IL-13 R alpha 1 which then forms a signaling complex with the transmembrane IL-4 R alpha (6-8). This high affinity receptor complex also functions as the type 2 IL-4 receptor (6, 7). IL-13 R alpha 2 inhibits responses to both IL-13 and IL-4. It binds IL-13 with high affinity (9, 10) and prevents IL-13 from signaling through the IL-13 R alpha 1/IL-4 R alpha complex (11, 12). It also blocks signaling through IL-4-occupied IL-13 R alpha 1/IL-4 R alpha receptor complexes (12, 13). In addition, IL-13-bound IL-13 R alpha 2 can directly promote tumor cell invasiveness and the development of tissue fibrosis (14-16).

Reference

1. Saggini, A. et al. (2011) Int. J. Immunopathol. Pharmacol. 24:305.

2. Gallo, E. et al. (2012) Eur. J. Immunol. 42:2322.

3. Liang, H.E. et al. (2012) Nat. Immunol. 13:58.

4. Ruetten, H. and C. Thiemermann (1997) Shock 8:409.

5. McKenzie, A.N. et al. (1993) Proc. Natl. Acad. Sci. USA 90:3735.

6. Aman, M.J. et al. (1996) J. Biol. Chem. 271:29265.

7. Zurawski, S.M. et al. (1995) J. Biol. Chem. 270:13869.

8. Andrews, A.L. et al. (2002) J. Biol. Chem. 277:46073.

9. Chen, W. et al. (2009) J. Immunol. 183:7870.

10. Daines, M.O. et al. (2007) J. Allergy Clin. Immunol. 119:375.

11. Kasaian, M.T. et al. (2011) J. Immunol. 187:561.

12. Andrews, A.-L. et al. (2006) J. Allergy Clin. Immunol. 118:858.

13. Rahaman, S.O. et al. (2002) Cancer Res. 62:1103.

14. Fujisawa, T. et al. (2009) Cancer Res. 69:8678.

15. Fujisawa, T. et al. (2011) Int. J. Cancer 131:344.

16. Fichtner-Feigl, S. et al. (2006) Nat. Med. 12:99.

Specifications

Synonyms	Human IL13; interleukin-13; IL13; IL-13; interleukin 13; MGC116786
Accession #	AAK53823
Source	Human embryonic kidney cell, HEK293-derived human IL-13 protein
Source	Gly21-Asn132
Predicted Moleucular weight	13.3 kDa

Components and Storage

Formulation	Solution protein.
	Dissolved in sterile PBS buffer.
	This solution can be diluted into other aqueous buffers. Centrifuge the vial prior to opening.
Storage and Stability	Avoid repeated freeze-thaw cycles.
	It is recommended that the protein be aliquoted for optimal storage.
	12 months from date of receipt, -20 to -70 °C as supplied.
Shipping	Shipping with dry ice

Quality

Purity	> 95%, determined by SDS-PAGE.
Endotoxin Level	<0.010 EU per 1 ug of the protein by the LAL method.
Activity	Measured in a cell proliferation assay using TF-1 human erythroleukemic cells.
Activity	The EC50 for this effect is 0.5-2.0 ng/mL.

SDS-PAGE

Gel filtration

Bioactivity

Documents

Human IL13