Recombinant Human IL-4 Receptor Alpha (IL-4 Rα)

IL-4 receptor alpha (IL-4 Rα), also known as IL4RA and CD124, is the alpha chain of the Il-4 receptor which binds to both IL-4 and IL-13 to regulate immune and allergenic responses. Hematopoietic cellular responses to IL-4 are mediated by a high affinity receptor complex comprised of the IL-4 Rα subunit and the common cytokine γ chain (CD132) (1). In non-hematopoietic cells, the IL-4 Rα subunit associates with the IL-13 Rα chain and serves as a functional complex for IL-13. IL-4 Rα is a single-pass type I transmembrane protein and similar to those present in the IL-2 receptor and GM-CSF receptor ß-chains. As a receptor for both IL-4 and IL-13, IL4 Rα couples to the JAK1/2/3-STAT6 pathway, and is involved in regulating IgE production and chemokine and mucus production at sites of allergic inflammation, as well as promoting differentiation of Th2 cells (2). The secreted extracellular domain of IL4 Rα, called sIL-4 Rα, can inhibit IL-4-mediated cell proliferation and IL-5 up-regulation by T cells but it has no signaling abilities. Allelic variations in the IL-4 Rα gene have been associated with atopy, a condition that can manifest itself as allergic rhinitis, sinusitis, asthma or eczema (3).

The biological activity of Human Soluble Interleukin-4 Receptor α is determined by its ability to inhibit the IL-4 dependent proliferation of human TF-1 cells. The expected ED₅₀ for this effect is 2 x 10⁵ units/mg.

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Gly24

Lyophilized

The predicted molecular weight of Recombinant Human IL-4R Alpha is Mr 24 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 30-35 kDa.

24

This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.3 with no calcium, magnesium, or preservatives.

This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.

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1. Nelms, K. et al. (1999) Annu. Rev. Immunol. 17:701
2. Jiang, H. et al. (2000) J. Allergy Clin. Immunol. 105:1063
3. Hall, IP. et al. (2000) Respir. Res. 1:6