Interleukin-21 (IL-21) is a type I cytokine that modulates functions of T, B, natural killer (NK), and myeloid cells. IL-21 is produced by activated T follicular helper cells (Tfh), Th17 cells, and NKT cells. Tfh-derived IL-21 plays an important role in the development of humoral immunity through its autocrine effects on the Tfh cell and paracrine effects on immunoglobulin affinity maturation, plasma cell differentiation, and B cell memory responses.The 133 amino acid (aa) mature human IL-21 protein shares 63% and 61% aa sequence identity with mouse and rat IL-21 protein, respectively. Alternative splicing generates an additional isoform with a substitution of the C-terminal 16 amino acids. IL-21 shows having much relation with clinical illnesses, including cancer immunotherapy, viral infections and allergies. And it suppresses cutaneous hypersensitivity reactions by limiting allergen-specific IgE production and mast cell degranulation. Product Properties Synonyms Interleukin-21, IL-21, Za11 Accession A3QPB9 GeneID 365769 Source E.coli-derived rat IL-21 protein, His18-Ser146. Molecular Weight Approximately 15.2 kDa under reducing conditions. AA Sequence HKSSPQRPDH LLIRLRHLMD IVEQLKIYEN DLDPELLTAP QDVKGQCEHE AFACFQKAKL KPSNTGNNKT FINDLLAQLR RRLPAKRTGN KQRHMAKCPS CDLYEKKTPK EFLERLKWLL QKMIHQHLS Tag None Physical Appearance Sterile Filtered White lyophilized (freeze-dried) powder. Purity > 96% by SDS-PAGE and HPLC analyses. Biological Activity The ED50 as determined by a cell proliferation assay using human N1186 cells is less than 50 ng/mL, corresponding to a specific activity of > 2.0 × 104 IU/mg. Fully biologically active when compared to standard. Endotoxin < 1.0 EU per 1μg of the protein by the LAL method. Formulation Lyophilized from a 0.2 μm filtered concentrated solution in PBS, pH 7.4. Reconstitution We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20℃. Further dilutions should be made in appropriate buffered solutions. Shipping and Storage The products are shipped with ice pack and can be stored at -20℃ to -80℃ for 1 year. Recommend to aliquot the protein into smaller quantities when first used and avoid repeated freeze-thaw cycles. Cautions 1. Avoid repeated freeze-thaw cycles. 2. For your safety and health, please wear lab coats and disposable gloves for operation. 3. For research use only!
