Three-dimensional structure-activity relationship modeling of cross-reactivities of a polyclonal antibody against pyrene by comparative molecular field analysis

Immunoassays have been regarded as a possible alternative or supplement for measuring polycyclic aromatic hydrocarbons (PAHs) in the environment. Since there are too many potential cross-reactants for PAH immunoassays, it is difficult to determine all the cross-reactivities (CRs) by experimental tests. In this study, the quantitative structure-activity relationship (QSAR) technique, comparative molecular field analysis (CoMFA), was applied to predict the CRs of a polyclonal antibody against pyrene. The CoMFA model developed shows that the CRs of the compounds are correlated to their 3D structure (n = 14, q2=0.527, r2=0.944, and Standard Error (SE) = 0.22478). The contributions of the steric and electrostatic fields to CRs are 95 and 5%, respectively. The results of the correlation predicted the CRs with actual CRs of randomly selected test compounds and showed that the developed model has good prediction ability. The QSAR model has been applied to predict the CRs of other 17 PAHs. The 3D-QSAR model and its respective contour plot could be useful tools to further understand the molecular nature of antibody-antigen interactions.