IL-21 stimulates proliferation of B cell stimulated by crosslinking of the CD40 antigen. It inhibits proliferation stimulated by IL-4 plus anti-IgM. IL-21 augments stimulation of the proliferation of naive CD45RA(+) but not memory CD45R0(+) T cells mediated by engagement of CD3. IL-21 stimulates the proliferation of bone marrow progenitor cells and the expression of the natural killer cell marker CD56 in the presence of IL-15. The Interleukin-21 receptor is closely related to human IL-2 beta receptor. The receptor contains a WSXWS motif in the extracellular region, typical of type 1 cytokine receptors. The receptor is expressed on natural killer cells, T cells, and B cell line. The functional signaling complex activates Janus kinases JAK1, JAK3, and the STAT proteins STAT1, and STAT3.
Quantity
100 µg
Regulatory
RUO
Source
E. coli
Host
Human
Endotoxin Level
<1.0 EU/μg of recombinant protein as determined by the LAL method.
Biological Activity Comment
The ED(50) was determined by the dose-dependent proliferation of HuT-78 Cells and was found to be <0.05ng/mL.
Weight
15.0 kDa
Description
A quick spin of the vial followed by reconstitution in distilled water to a concentration not less than 0.1 mg/mL. This solution can then be diluted into other buffers.
Format
Lyophilized PowderRecombinant Interleukin-21 was lyophilized from a 0.2 μm filtered PBS solution pH 7.5.
Purity
>95% as determined by SDS-PAGE
Storage
The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at 2° - 8°C for one month, or at -20°C for six months, with a carrier protein without detectable loss of activity. Avoid repeated freeze/thaw cycles.