Recombinant Human IL-13

Interleukin 13 (IL-13), also known as ALRH, is a single-chain, glycosylated polypeptide and a cytokine that is critical in regulating inflammatory and immune responses.¹ It is produced primarily by activated Th2 cells, as well as mast cells and Natural Killer (NK) cells.¹ The functions of IL-13 overlap considerably with those of IL-4 but these effects are probably less important given the more potent role of IL-4.² IL-13 exerts its effects through a multi-subunit receptor comprising the alpha chain of the IL-4 receptor (IL-4Rα), and at least one of two known IL-13-specific binding chains (IL13 Rα1 and IL13 Rα2). Most of the biological effects of IL-13, like those of IL-4, are linked to signal transducer and activator of transcription 6 (STAT6).² Although IL-13 is associated primarily with the induction of airway disease, it also has anti-inflammatory properties. It exerts these anti-inflammatory effects on monocytes and macrophages, and inhibits the expression of inflammatory cytokines such as IL-1beta, TNF-alpha, IL-6 and IL-8. IL-13 has also been shown to enhance B cell proliferation and to induce isotype switching resulting in increased production of IgE.³ Blocking of IL-13 activity inhibits the pathophysiology of asthma.⁴ Targeted deletion of IL-13 in mice results in impaired Th2 cell development and indicates an important role for IL-13 in the expulsion of gastrointestinal parasites.⁵ In addition, studies have identified IL-13 expression as a common feature of cHL (classical Hodgkin lymphoma).⁶ Human and murine IL-13 are cross-species reactive.

The biological activity of Human IL-13 was determined in a cell proliferation assay using a human factor-dependent cell line, TF-1 (Kitamura, T. et al., 1989, J. Cell Physiol. 140:323). The expected ED₅₀ for this effect is typically 0.75 - 3.5 ng/ml. The cell number is assessed in a fluorometric assay using the redox sensitive dye, Resazurin.

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Gly21

Lyophilized

The predicted molecular weight of Recombinant Human IL-13 is Mr 12.3 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 9 kDa. The 110 residue protein is C-terminally truncated.

12.3

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.

Next Day Ambient

1. Wynn, TA. et al. (2003) Annu Rev Immunol. 21: 425
2. Citrin, DE. et al. (2016) Sci Rep. 6:39714.