DESCRIPTION Gene Name Synonym IL21, Za11, Interleukin-21 Species Human A ccession Q9HBE4 Source HEK293 cells SPECIFICATIONS Amino acid sequence His25-Ser162 is expressed with a 10×His tag at the C terminus Molecular Weight 17.4 kDa Purity >95.0% as determined by SDS-PAGE Endotoxin <5 EU·mg -1 Formulation Lyophilized from sterile PBS, pH 7.4.Normally 5%-8% trehalose and mannitol are added as protectants before lyophilization. Reconstitution Dissolved in sterile water, it is recommended to add 0.1% HSA or BSA for long-term preservation. STORAGE Stability and Storage 12 months from date of receipt at -20°C to -70°C. After reconstitution, it is stable at 4°C for 1 week or -20°C for almost 6 months (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage. BACKGROUND Interleukin-21 (IL-21) produced predominantly by CD4+ T cells and natural killer T (NKT) cells. Interleukin-21 (IL-21) is a secreted protein which belongs to the IL-15 / IL-21 family. It binds to a composite receptor consisting of a private receptor (IL21R) and the common cytokine receptor gamma chain (gamma(C)). Interleukin-21 / IL-21 impacts a number of cell types, including CD8+ memory T cells, NK cells and subsets of CD4 memory T cells. The IL-21R is widely distributed on lympho-haematopoietic cells. IL-21 is a pleiotropic cytokine produced by CD4+ T cells in response to antigenic stimulation. Its action generally enhances antigen-specific responses of immune cells. IL-21 promotes the anti-tumor activity of CD8+ T-cells and NK cells. IL-21 exerts its effect through binding to a specific type I cytokine receptor, IL-21R, which also contains the γ chain (γc) found in other cytokine receptors including IL-2, IL-4, IL-7, IL-9 and IL-15. The IL-21/IL-21R interaction triggers a cascade of events which includes activation of the tyrosine kinases JAK1 and JAK3, followed by activation of the transcription factors STAT1 and STAT3. Data SDS-PAGE Bioactivity Recombinant Human IL-21 Protein was determined by SDS-PAGE with Coomassie Blue, showing a band at 11-20 kDa. Measured by its ability to induce Interferon-gamma secretion by human natural killer lymphoma NK-92 cells. The ED50 for this effect is typically 10-50 ng/ml. 仅供科研用途，不可用于临床诊断！