Recombinant Human IL-21 Protein, Seafrom (CAT#: STEM-CT-0023-ZJF)

The Recombinant Human IL-21 Protein manufactured by Seafrom is suitable for immunomodulatory and regulatory functions in immune cell differentiation.
Interleukin-21 (IL-21) is a pleiotropic cytokine produced by CD4+ T cells in response to antigenic stimulation. IL-21 enhances antigen-specific immune responses. It is primarily secreted by activated T follicular helper cells (Tfh), Th17 cells, and NKT cells. IL-21 exerts its biological effects through the γc heterodimer receptor complex and IL-21R, a specific receptor for IL-21.
IL-21 derived from Tfh cells plays a crucial role in humoral immune differentiation and B-cell memory responses. It does this through autocrine actions on Tfh cells, which leads to immunoglobulin affinity maturation, plasma cell development, and the requirement for dendritic cell migration to draining lymph nodes. IL-21 has a broad impact on various T-cell functions, co-stimulating the activation, proliferation, and survival of CD8+ T cells. It also promotes Th17 cell polarization and hampers the production of regulatory T cells while limiting their inhibitory effect on CD4+ T cells.
The IL-21/IL-21R binding enhances the cytolytic activity of activated NK cells and their production of IFN-γ while restraining the expansion of resting NK cells. Additionally, IL-21 exhibits inhibitory effects on skin allergies by limiting allergen-specific IgE production and mast cell degranulation. Dysregulation of the IL-21/IL-21R system is associated with various immunological disorders. IL-21 carries out its functions by binding to a specific type I cytokine receptor, IL-21R. After IL-21 binding to IL-21R, tyrosine kinases JAK1 and JAK3 are activated, followed by activation of the transcription factors STAT1 and STAT3.
The lyophilized formulation can be stored at 2-8°C for 24 months. For reconstitution, it can be dissolved in injection-grade water, physiological saline, culture medium, or PBS. After dissolution, it should be divided into smaller aliquots and stored at -20°C for 6 months or at -80°C for 12 months, with a final concentration after dilution not lower than 100 μg/mL. Avoid repeated freeze-thaw cycles.

Expression Host: CHO Cells
Synonyms: IL21, Za11, IL-21
Protein Sequence: DNA sequence encodes human IL-21 (Q9HBE4-1: Q29-S162) with an Fc tag at the C-terminus, predicted molecular weight of 41.9 kD
Purity: >95%, analyzed by SDS-PAGE and HPLC
Endotoxin Level: <0.01 EU/μg
Biological Activity: Measurement of the ability to induce interferon-gamma secretion by human NK-92 cells, ED50 ≤ 50 ng/mL
Purification Method: Chromatographic purification
Appearance: White loose body

Stable Cell Library
Large-Scale Expression
High Activity
Batch Stability
Gmp-Quality Control
Ensured Product Quality

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