| 背景 | This is a mouse monoclonal anti-idiotype antibody (IgG2a, kappa) raised against the biologic drug etanercept, recognising the idiotypic region of the etanercept molecule. It is a non-neutralising clone, meaning it binds etanercept without blocking the drug's TNF-binding activity, which makes it well suited to bridging or capture formats where total drug (free plus bound) must be measured. Validated for ELISA, Western blot and immunohistochemistry, it functions as a critical reagent for pharmacokinetic assays, anti-drug antibody (ADA) assay development, and bioanalytical characterisation of etanercept and its biosimilars. Supplied as a bulk, research-use-only reagent at low endotoxin, it is intended for assay building, calibration/standard curve work, positive-control and surrogate-ADA applications, and QC of biosimilar batches. Because etanercept is a human therapeutic fusion protein rather than a rodent cell-surface target, this reagent is used in vitro and in bioanalytical workflows rather than in animal dosing studies. Non-neutralising specificity is the key selling point for total-drug quantitation.
Etanercept is a recombinant human fusion protein combining the extracellular ligand-binding domain of the p75 TNF receptor 2 (TNFR2/CD120b) with the Fc portion of human IgG1. It acts as a soluble decoy receptor, binding and neutralising both tumour necrosis factor alpha (TNF-alpha) and lymphotoxin-alpha (TNF-beta), thereby preventing their engagement of cell-surface TNF receptors and dampening downstream pro-inflammatory NF-kB and MAPK signalling. By sequestering these cytokines, etanercept reduces the inflammatory cascade that drives synovitis, joint destruction and other autoimmune pathology. Clinically it is used in rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, juvenile idiopathic arthritis and plaque psoriasis. The dimeric Fc scaffold gives it a prolonged serum half-life. As an anti-idiotype target, its unique receptor-domain fold provides the epitope this antibody recognises. |
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