Orthogonal quantification of soluble inducible T-cell costimulator(ICOS)in healthy and diseased human serum

作     者：Kevin McKinski Dean McNulty Francesca Zappacosta Mary Birchler Matt Szapacs Christopher Evans Kevin McKinski;Dean McNulty;Francesca Zappacosta;Mary Birchler;Matt Szapacs;Christopher Evans

作者机构：BioanalysisImmunogenicity&BiomarkersGlaxoSmithKlineCollegevillePA19426USA 

出 版 物：《Journal of Pharmaceutical Analysis》 (药物分析学报（英文版）)

年 卷 期：2022年第12卷第2期

页      面：317-323页

核心收录：

学科分类：1007[医学-药学(可授医学、理学学位)] 1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

基　　金：GlaxoSmithKline  GSK 

主　　题：ICOS Immunoassay LC-MS/MS Biomarker HAMA 

摘      要：Inducible T-cell costimulator(ICOS),a homodimeric protein expressed on the surface of activated T-cells,is being investigated as a potential therapeutic target to treat various cancers.Recent studies have reported aberrant increases in the soluble form of ICOS(sICOS)in human serum in disease-state patients,primarily using commercial ELISA kits.However,results from our in-house immunoassay did not show these aberrant increases,leading us to speculate that commercial sICOS ELISAs may be prone to interference.We directly tested that hypothesis and found that one widely used commercial kit yields falsepositives and is prone to human anti-mouse antibody interference.We then analyzed a panel of healthy,cancer,chronic hepatitis C virus,systemic lupus erythematosus,and diffuse cutaneous systemic sclerosis human serum using our in-house immunoassay and reported the measured sICOS concentrations in these populations.Since even well characterized immunoassay methods are prone to non-specific interference,we also developed a novel sICOS LC-MS/MS method to confirm the results.Using these orthogonal approaches,we show that sICOS is a low abundance soluble protein that cannot be measured above approximately 20 pg/mL in human serum.