Knight G J, Wylie P, Holman M S, Haddow J E
Clin Chem. 1985 Jan;31(1):118-21.
We describe an 125I-based RIA for cotinine, the major metabolite of nicotine. The slope of the dose-response curve was quite shallow (6-8% change in binding per doubling dose), resulting in between-assay CVs of 15 to 20%. This effect occurred because the radioligand formed by linking a cotinine derivative to tyramine manifested greater affinity for the anti-cotinine antibodies than did cotinine itself. We absorbed the serum with a derivative of nicotine coupled to the carrier protein via a chemical bridge similar to that used to form the cotinine/carrier protein immunogen. An RIA in which we used such absorbed serum showed a significantly increased slope of the dose-response curve (11-13% change in binding per doubling dose), and between-assay CVS were only 6 to 8%. We suggest that this improvement results because absorption removes anti-bridge antibodies directed against the chemical-bond common to the cotinine/carrier-protein immunogen and to the cotinine/tyramine radioligand.
我们描述了一种基于125I的可替宁放射免疫分析方法，可替宁是尼古丁的主要代谢产物。剂量反应曲线的斜率相当平缓（每剂量加倍时结合变化6 - 8%），导致分析间变异系数为15%至20%。出现这种情况是因为将可替宁衍生物与酪胺连接形成的放射性配体对抗可替宁抗体的亲和力比对可替宁本身的亲和力更大。我们用一种通过与用于形成可替宁/载体蛋白免疫原的化学桥类似的化学桥与载体蛋白偶联的尼古丁衍生物吸收血清。使用这种吸收后的血清进行的放射免疫分析显示剂量反应曲线的斜率显著增加（每剂量加倍时结合变化11 - 13%），且分析间变异系数仅为6%至8%。我们认为这种改进的原因是吸收去除了针对可替宁/载体蛋白免疫原和可替宁/酪胺放射性配体共有的化学键的抗桥抗体。
