Recombinant Macaca fascicularis Interleukin-21 receptor (IL21R), partial (Active)

IL-21 receptor signaling plays a pivotal role in T cell and NK cell differentiation, making the extracellular domain (aa 41–253) a critical tool for dissecting cytokine-mediated immune responses in preclinical primate models. Expressed in mammalian cells to preserve native glycosylation and disulfide architecture, this C-terminally His-tagged protein demonstrates quantified binding to human IL-21 with an EC50 of 15.01–19.43 ng/mL in functional ELISA and a KD of 1.31 nM by surface plasmon resonance, providing validated performance for ligand-receptor interaction studies and competitive inhibition assays. These affinity metrics support its use in therapeutic antibody epitope mapping, blocking antibody screening, and small-molecule inhibitor discovery campaigns targeting IL-21 signaling pathways implicated in cancer immunology. The protein meets the purity and endotoxin criteria typical for quantitative binding assays (>95% pure, <1.0 EU/μg), aligning with standards expected in SPR, biolayer interferometry, and high-throughput screening workflows.