Using hapten cross-reactivity to screen heterologous competitive antigens for improving the sensitivity of ELISA

• Published in: Food chemistry 2020-01, Vol.303, p.125379-125379, Article 125379
• Main Authors: Hu, Song, Huang, Zhen, Wang, Chun, Peng, Juan, Lai, Wei-Hua
• Format: Article
• Language: English
• Subjects: Biolayer interferometry; Cross-reactivity; Heterologous competitive strategy; Molecular docking; Quinolones; Sensitivity of ELISA
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2019.125379

[Display omitted] •HCAs may improve ELISA sensitivity with CRs from 0.77% to 49.92% in the study.•HCAs that may improve ELISA sensitivity exhibited 10−7 to 10−9 M affinities with mAb.•ELISA sensitivity (IC50) based on HCA was enhanced 26-fold (0.2 ng/mL).•The LOD of the proposed ELISA for detection of NOR in milk was 0.016 ng/mL. In this study, heterologous competitive antigens (HCAs) suitable for improving the sensitivity of ELISA were successfully screened based on their cross-reactivities (CRs) with 19 quinolone analogues; each containing the norfloxacin amino derivative (NOR0) coupled with bovine serum albumin (BSA) as a coating antigen. HCAs prepared with hapten analogues (CRs of 0.77%–49.92%) remarkably enhanced the sensitivity of the subsequent ELISA. ELISA sensitivity for NOR detection improved 26-fold when moxifloxacin–BSA was used as a heterologous coating antigen relative to when NOR0–BSA was used as a homologous coating antigen. This work, therefore, represents a detailed screening method to select suitable heterologous competitive antigens that improve ELISA sensitivity. Secondly, we present new theoretical tools to estimate hapten structures for use in the method, which may also be applied to improve the sensitivity of other immunoassays.