Contents: Recombinant Human IL-21 Single-Use ELISA RSG Standard
Catalog Number: 39-8219
Formulation: Sterile liquid; phosphate buffered saline, pH 7.2, 150 mM NaCl, with 1.0% BSA. 0.22 µm filtered.
Storage Conditions: The frozen cytokine standard is already aliquoted at 20 µl per vial. Upon receipt, frozen cytokine standard should be immediately stored at -80°C; stable for at least 12 months. After thawing, quick-spin vial prior to opening. Do not re-aliquot into smaller fractions. These are single use vials. Use one time and discard.
Handling Conditions: For best recovery, always quick-spin vial prior to opening. For dilution of current stock, always include carrier protein (1% BSA or 10% FBS) in the buffered saline diluent.
Source: Protein expressed in E. coli.
Purity: Greater than 98%, as determined by SDS-PAGE
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Description
Human Interleukin-21 (IL-21) is a 162-amino acid protein with 57% identity to the mouse gene. It contains a 31-amino acid signal peptide and a 4-helix-bundle cytokine domain homologous to IL-2, IL-4 and IL-15. IL-21 stimulates B cell proliferation in an anti-CD40 dependent manner but inhibits B cell proliferation stimulated by IL-4 plus anti-IgM. IL-21 is induced by IL-6 in activated T cells, a process that is dependent on STAT3 but not on ROR-gamma. IL-21 induces Th17 differentiation and suppresses FOXP3 expression, which requires STAT3 and ROR-gamma.
Applications Reported
For research use only, not for diagnostic or therapeutic use. Recombinant human IL-21 is biologically active. The intended use of the Recombinant Human IL-21 Single-Use ELISA RSG Standard is as a standard for human IL-21 Ready-SET-Go! ELISA and human IL-21 matched antibody pair ELISA. Typically the standard is run in a series of 7 doubling dilutions from the ‘top’ standard described below.
Instructions for use:
For Ready-SET-Go! ELISA Set (TMB substrate). Dilution: Add 20 ul of standard solution to 5 ml of assay diluent to prepare the top standard solution (4000 pg/ml).
Note: These are single-use vials. Use one time and discard. Dilute as suggested above, not difficult-to-measure fractions of the suggested volumes (e.g., not 0.5 ul in 1.0 ml) or recovery may not be accurate. Use within 6 hours of dilution to top standard concentration.
Applications Tested
This cytokine standard has been calibrated, and subsequently tested by sandwich ELISA using the human IL-21 ELISA pair (eBio3A3-N2 and eBio2B2-G20).
References
Korn, T. et al. 2007. Nature. 448:484-487
