Recombinant Human IL-21

Interleukin 21 (IL-21) is a T cell-derived pleiotropic cytokine that has potent regulatory effects on cells of the immune system, including natural killer (NK) cells and cytotoxic T cells that can destroy virally infected or cancerous cells.^1,2 This cytokine induces cell division/proliferation in its target cells. IL-21 elicits its effects on immune cells by interacting with a cell surface receptor known as the interleukin 21 receptor, IL-21R, which is expressed in bone marrow cells and various lymphocytes. IL-21 is closely related to IL-2 and IL-15³ and is a key factor in the transition between innate and adaptive immune responses.⁴ The critical role of IL21 in promoting humoral immune responses makes it an important focus of potential therapeutic interventions in conditions characterised by overproduction of pathogenic autoantibodies.⁵

The biological activity of Human IL-21 was determined determined by the dose-dependant stimulation of human peripheral blood mononuclear cells. The expected ED₅₀ is <5 ng/ml.

MQDRHMIRMR QLIDIVDQLK NYVNDLVPEF LPAPEDVETN CEWSAFSCFQ KAQLKSANTG NNERIINVSI KKLKRKPPST NAGRRQKHRL TCPSCDSYEK KPPKEFLERF KSLLQKMIHQ HLSSRTHGSE DS

Lyophilized

The molecular weight of Recombinant Human IL-21 is Mr 15.4 kDa.

This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.4 containing 5.0% w/v trehalose with no calcium, magnesium, or preservatives.

This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.

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1. Foster D et al. (2000) Nature 408: 57 2. Clegg CH et al. (2002) J. Leukoc. Biol. 72: 856 3. Leonard WJ.et al. (2002) Science 298: 1630 4. Joannopoulos K.et al. (2003) J. Immunol. 171: 608 5. Lipsky PE. et al. (2008) Ann Rheum. Dis. 3: 83