IL-24, Recombinant, Mouse, aa66-220 (Interleukin 24, C49A, FISP, MDA-7, MOB-5, ST16)

Interleukin 24 (IL­24), also known as FISP (IL­4 induced secreted protein) in mouse, and mda­7 (melanoma differentiation associated gene­7) in humans, is a member of the IL­10 family of helical cytokines (1­3). The mouse IL­24 gene encodes for a 181 amino acid (aa) precursor that includes a 26 aa signal sequence and an 18kD (predicted), 155 aa mature segment (4). Unlike mature human IL­24, which contains three potential N­linked glycosylation sites, mouse mature IL­24 has only one. In human, both glycosylation and the presence of an intrachain disulfide bond have been found to be necessary for full activity (5). This requirement for glycosylation is unique among IL­10 family members. Presumably, the same structural modifications apply to mouse IL­24. Mouse IL­24 is a 27kD protein when secreted, and is active on human receptors (1, 3). Mature mouse IL­24 shares 69%, 84%, 69%, 68% and 61% aa sequence identity with human, rat, equine, canine and bovine IL­24, respectively. A 119 aa isoform termed FISP­sp diverges at aa 77. FISP­sp has been found mainly in the endoplasmic reticulum of Th2 cells. It can dimerize with intracellular IL­24, and antagonize the pro­apoptotic effects of IL­24 (6). Under physiological conditions, cytokine­stimulated monocytes/macrophages and Th2 cells produce most secreted IL­24, other sources include B cells, keratinocytes, NK cells, and differentiating melanoma cells (1­3, 7­9). Secreted IL­24 binds and signals through complexes of IL­20 Ralpha:IL­20 Rbeta, or IL­22 R:IL­20 Rbeta (10). The IL­20 Ralpha:IL­20 Rbeta complex is also a receptor for IL­19 and IL­20, while IL­22 R:IL­20 Rbeta binds IL­20 (2, 10). Both receptors are widely expressed, but have not been found on hematopoietic cells (3). Even so, IL­24 induces type I proinflammatory cytokines in monocytes, and inhibits plasma cell differentiation in germinal center B cells (8, 11). The phenotype of mice transgenic for IL­24 is similar to that of IL­20 and IL­22 transgenic mice, indicating overlap in their activities, particularly in the skin (12). Secreted IL­24 is anti­angiogenic, binding receptors on endothelial cells and blocking their differentiation (13). Intratumoral injection of adenovirus coding for IL­24 causes tumor­specific apoptosis in humans, but it is not clear whether secreted IL­24 contributes to this effect (14). Source: Recombinant protein corresponding to aa66-220 from mouse IL-24, NS0-derived. Molecular Weight: ~19-23kD, Endotoxin: <0.10EU/1ug (LAL method), Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute in sterile ddH2O or PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.