Production and characterization of a broad-specificity polyclonal antibody for O, O-diethyl organophosphorus pesticides and a quantitative structure–activity relationship study of antibody recognition

• Published in: Analytica chimica acta 2009-08, Vol.647 (1), p.90-96
• Main Authors: Xu, Zhen-Lin, Xie, Gui-Mian, Li, Yong-Xiang, Wang, Bing-Feng, Beier, Ross C., Lei, Hong-Tao, Wang, Hong, Shen, Yu-Dong, Sun, Yuan-Ming
• Format: Article
• Language: English
• Subjects: Antibodies - chemistry; Antibodies - immunology; Antibodies, immunoglobulins; Antibody recognition; Antibody Specificity; Biological and medical sciences; Broad-specificity; Enzyme-Linked Immunosorbent Assay - methods; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Haptens - chemistry; Haptens - immunology; Heterologous assay; Molecular immunology; Organophosphorus pesticides; Organothiophosphorus Compounds - analysis; Organothiophosphorus Compounds - immunology; Pesticides - analysis; Pesticides - immunology; Quantitative Structure-Activity Relationship; Regression Analysis
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2009.05.025

Polyclonal antibody (PAb) with broad-specificity for O, O-diethyl organophosphorus pesticides (OPs) against a generic hapten, 4-(diethoxyphosphorothioyloxy)benzoic acid, was produced. The obtained PAb showed high sensitivity to seven commonly used O, O-diethyl OPs in a competitive indirect enzyme-linked immunosorbent assay (ciELISA) using a heterologous coating antigen, 4-(3-(diethoxyphosphorothioyloxy)phenylamino)-4-oxobutanoic acid. The 50% inhibition value (IC 50) was 348 ng mL −1 for parathion, 13 ng mL −1 for coumaphos, 22 ng mL −1 for quinalphos, 35 ng mL −1 for triazophos, 751 ng mL −1 for phorate, 850 ng mL −1 for dichlofenthion, and 1301 ng mL −1 for phoxim. The limit of detection (LOD) met the ideal detection criteria of all the seven OP residues. A quantitative structure–activity relationship (QSAR) model was constructed to study the mechanism of antibody recognition using multiple linear regression analysis. The results indicated that the frontier-orbital energies (energy of the highest occupied molecular orbital, E HOMO, and energy of the lowest unoccupied molecular orbital, E LUMO) and hydrophobicity (log of the octanol/water partition coefficient, log P) were mainly responsible for the antibody recognition. The linear equation was log(IC 50) = −63.274 E HOMO + 15.985 E LUMO + 0.556 log P − 25.015, with a determination coefficient ( r 2) of 0.908.