Anti-Interleukin-21 (IL-21) (IN) Antibody

Cytokine with immunoregulatory activity. May promote the transition between innate and adaptive immunity. Induces the production of IgG(1) and IgG(3) in B-cells (By similarity). Implicated in the generation and maintenance of T follicular helper (Tfh) cells and the formation of germinal-centers. Together with IL6, control the early generation of Tfh cells and are critical for an effective antibody response to acute viral infection (By similarity). May play a role in proliferation and maturation of natural killer (NK) cells in synergy with IL15. May regulate proliferation of mature B- and T-cells in response to activating stimuli. In synergy with IL15 and IL18 stimulates interferon gamma production in T-cells and NK cells (PubMed:11081504, PubMed:15178704). During T-cell mediated immune response may inhibit dendritic cells (DC) activation and maturation (By similarity). {UniProtKB:Q9ES17, PubMed:11081504, PubMed:15178704}.

This antibody recognizes human IL-21, a cytokine that has significant homology to IL-2, IL-4, and IL-15. The receptor for IL-21, IL-21R, complexes with the common cytokine receptor g chain, gc, and mediates IL-21 signaling. IL-21 and its receptor activate the JAK-STAT signaling pathway. IL-21 is expressed in activated T cells and the HL-60 and THP-1 cell lines. IL-21 is associated with the proliferation and maturation of NK, B and T cell populations.