Hu Recom IL-21, 1000 µg

Interleukin-21 (IL-21) is a pleiotropic type I cytokine secreted by activated CD4+ T follicular helper and Th17 cells. This recombinant human IL-21 from STEMCELL Technologies is supplied as a 1000 µg lyophilized vial for reconstitution in sterile deionized water or culture buffer prior to use in vitro.

IL-21 signals through the IL-21 receptor (IL-21R) paired with the common gamma chain, activating JAK1/JAK3 and STAT3 pathways. Researchers use it to drive B cell differentiation into plasmablasts and antibody-secreting plasma cells, support NK cell maturation and cytotoxicity, promote Th17 polarization, and modulate CD8+ cytotoxic T lymphocyte responses. The cytokine is widely applied to study germinal center reactions, immunoglobulin class switching, and the development of human lymphocyte populations from cord blood or peripheral blood-derived progenitors.

For handling, store the lyophilized vial at -20 °C, protected from light. After reconstitution, aliquot into single-use portions to avoid repeated freeze-thaw cycles, and store at -80 °C for long-term activity. Working concentrations in lymphocyte culture generally fall between 10 and 100 ng/mL depending on cell type and experimental readout. Each lot is verified for bioactivity using a proliferation-based cell assay, with purity confirmed by SDS-PAGE and endotoxin levels reported as suitable for sensitive primary cell culture.