Invitrogen™ Mouse IL-15/IL-15R Complex

Interleukin-15 (IL-15) is a 14 kDa proinflammatory protein that has been shown to play a role in the activation of neutrophils, dendritic cells, and macrophages, and is essential to the development and survival of NK cells and CD8 T-cells. IL-15 activates Jak/Stat pathways by signaling through a heterotrimeric receptor. Two of the subunits of this receptor, beta and gamma, are shared with the IL-2 receptor, while the alpha subunit is unique to IL-15.Despite the expression of IL-15 mRNA in many cell types, the secreted protein is rarely detectable in biological samples. Recent research suggests that IL-15 is retained inside the cell and is only secreted in complex with its unique receptor, IL-15R alpha. This chaperoning is required from the ER to Golgi through to secretion. The cytokine/receptor complex may stay bound to the cell surface, where it can be trans-presented to cells expressing the beta/gamma subunits of the receptor, or may be secreted in a soluble form that lacks the transmembrane domain of the receptor. The soluble IL-15/IL-15R complex is produced by mouse dendritic cells, fibroblasts, and macrophages, and demonstrates a 10-100-fold increase in agonistic activity over IL-15 alone. Description: This recombinant protein is the heterocomplex of the mouse IL-15 linked to soluble IL-15 receptor alpha chain (sushi domain) via a GS linker. Interleukin 15 (IL-15) is a cytokine that stimulates T and NK cell proliferation and differentiation. IL-15 regulates macrophage proinflammatory and chemotactic protein production. In addition, it induces differentiation of monocytes towards dendritic cells. The receptor for IL-15 is a high affinity heterotrimeric receptor composed of IL-15Ralpha and 2 additional subunits of the IL-2 receptor (beta and gamma). Upon activation, the receptor complex signals via the Stat and JAK pathways. It has been reported that the soluble form of IL-15Ralpha corresponding to the entire extracellular domain, cleaved by MMP′s, behaves as a high affinity IL-15 antagonist, whereas the recombinant extracellular domain comprised of the sushi domain together with the ligand, IL-15, behaves as a potent agonist by enhancing binding of IL-15 to the receptor complex. In fact, this receptor-ligand complex has approximately 10-100 fold increased proliferative activity. Applications Reported: Recombinant mouse IL-15/IL-15RA complex is biologically active. Applications Tested: The ED50 of this protein, as measured by CTLL-2 cell proliferation assay, is less than or equal to 4ng/mL. This corresponds to a specific activity of greater than or equal to 2.5 x 10e5 Units/mg. Source: Insect cell expressed N-terminal His-Tagged mIL-15Ra Gly33-Ala132 accession &Num; NP_032384-GS linker-mIL-15 Asn49-Ser162 accession &Num; NP_032383. Bioactivity: The ED50 of this protein, as measured by CTLL-2 cell proliferation assay, is less than or equal to 4ng/mL. This corresponds to a specific activity of greater than or equal to 2.5 x 10e5 Units/mg. Endotoxin: Less than 0.1ng/ug cytokine as determined by the LAL assay. Purity: >98% as determined by SDS-PAGE. Molecular Weight: 29.4 kDa. Storage and handling: For best recovery, quick-spin vial prior to opening. Use in a sterile environment. Purity: Greater than 90%, as determined by SDS-PAGE. Aggregation: Less than 10%, as determined by HPLC. Filtration: 0.2μm post-manufacturing filtered.