| Details of Functionality | Measured in a cell proliferation assay using TF‑1 human erythroleukemic cells. Kitamura, T. et al. (1989) J. Cell Physiol. 140:323. The ED50 for this effect is 0.0500-0.200 ng/mL. The specific activity of Recombinant Human IL-4 is >1.00 x 107 IU/mg, which is calibrated against human IL-4 WHO International Standard (NIBSC code: 88/656). |
| Source | E. coli-derived human IL-4 protein His25-Ser153, with an N-terminal Met Produced using non-animal reagents in an animal-free laboratory. |
| Accession # | |
| N-terminal Sequence | Met |
| Protein/Peptide Type | Animal-Free Recombinant Proteins |
| Gene | IL4 |
| Purity | >97%, by SDS-PAGE under reducing conditions and visualized by silver stain. |
| Purity Statement | Antigen Affinity-purified |
| Endotoxin Note | <0.01 EU per 1 μg of the protein by the LAL method. |
| Dilutions |
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| Theoretical MW | 15 kDa. Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors. |
| SDS-PAGE | 14 kDa, reducing conditions |
| Storage | Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
|
| Buffer | Lyophilized from a 0.2 μm filtered solution in PBS. |
| Purity | >97%, by SDS-PAGE under reducing conditions and visualized by silver stain. |
| Reconstitution Instructions | Reconstitute at 0.2 mg/mL in sterile PBS. |
Interleukin-4 (IL-4), also known as B cell-stimulatory factor-1, is a monomeric, approximately 13 kDa‑18 kDa Th2 cytokine that shows pleiotropic effects during immune responses (1‑3). It is a glycosylated polypeptide that contains three intrachain disulfide bridges and adopts a bundled four alpha -helix structure (4). Human IL-4 is synthesized with a 24 aa signal sequence. Alternate splicing generates an isoform with a 16 aa internal deletion. Mature human IL-4 shares 55%, 39% and 43% aa sequence identity with bovine, mouse, and rat IL-4, respectively. Human, mouse, and rat IL-4 are species-specific in their activities (5‑7). IL-4 exerts its effects through two receptor complexes (8, 9). The type I receptor, which is expressed on hematopoietic cells, is a heterodimer of the ligand binding IL-4 R alpha and the common gamma chain (a shared subunit of the receptors for IL-2, -7, -9, -15, and ‑21). The type II receptor on nonhematopoietic cells consists of IL-4 R alpha and IL‑13 R alpha 1. The type II receptor also transduces IL-13 mediated signals. IL-4 is primarily expressed by Th2-biased CD4+ T cells, mast cells, basophils, and eosinophils (1, 2). It promotes cell proliferation, survival, and immunoglobulin class switch to IgG4 and IgE in human B cells, acquisition of the Th2 phenotype by naïve CD4+ T cells, priming and chemotaxis of mast cells, eosinophils, and basophils, and the proliferation and activation of epithelial cells (10‑13). IL-4 plays a dominant role in the development of allergic inflammation and asthma (12, 14).
Animal-Free Manufacturing Conditions
Our dedicated controlled-access animal-free laboratories ensure that at no point in production are the products exposed to potential contamination by animal components or byproducts. Every stage of manufacturing is conducted in compliance with R&D Systems' stringent Standard Operating Procedures (SOPs). Production and purification procedures use equipment and media that are confirmed animal-free.
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