A Monoclonal Immunoassay for the Coplanar Polychlorinated Biphenyls

Abstract

Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants with diverse toxic, teratogenic, reproductive, immunotoxic, and tumorigenic effects. Three of the least abundant of the 209 PCB isomers (congeners) are the most toxic and most difficult to quantify. These are 3,4,3',4'-tetrachlorobiphenyl, 3,4,3',4',5'-pentachlorobiphenyl, and 3,4,5,3',4',5'-hexachlorobiphenyl (IU-PAC No. 77, 126, and 169, respectively). An immunizing hapten was designed to retain the 3,4,3',4' chlorine-substitution pattern and coplanarity characteristic of these toxic congeners. The optimal competitors for immunoassay were weaker binding distinctive single-ring fragments of the PCBs. A monoclonal antibody designated S2B1 was derived and used in direct (antibody-capture) competitive enzyme immunoassays (EIAs). The EIAs are highly specific for non-ortho-substituted congeners and do not recognize the more prevalent but much less toxic noncoplanar PCB congeners or 2,3,7,8-tetrachlorodibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzofuran, or dichlorobenzenes. Hapten and competitor design for this assay suggests a basis for development of sensitive EIAs for other classes of PCB congeners.

Structural basis for preferential binding of non-ortho-substituted polychlorinated biphenyls by the monoclonal antibody S2B1

“…Docking simulations were done with PCB77 and other congeners to evaluate and compare the two models of S2B1, reveal the orientation of S2B1-bound PCB, investigate the structural basis of S2B1 selectivity, and determine whether the simulations were consistent with previously published results of ELISA and kinetic exclusion fluoroimmunoassay (KinExa; Chiu et al, 1995Chiu et al, , 2000Chiu et al, , 2001. We first docked PCB77 manually into the binding site of each S2B1 model with computer graphics and used molecular mechanics energy minimization to relax surrounding antibody side chains and optimize the geometry of PCB77.…”

“…The PRO-CHECK overall G-factor for both models was À0.3, which is comparable to, or better than, that observed for wellrefined crystallographic structures at a resolution of 2.5 Å . Table 3 to models A and B, vs the log 10 of the I 50 (half-maximal inhibition) of each congener in a direct competition ELISA, as reported by Chiu et al (1995). The line is a least-square fit.…”

“…S2B1 is exclusively selective for the non-ortho-chlorinated PCB congeners 35, 77 and 126 in indirect and direct competitive enzyme-linked immunosorbent assays (ELISAs; Carlson et al, 1995;Chiu et al, 1995Chiu et al, , 2000. PCBs 35 (3,4,3 0 -trichlorobiphenyl), 77 (3,4,3 0 ,4 0 -tetrachlorobiphenyl) and 126 (3,4,5,3 0 ,4 0 -pentachlorobiphenyl) are bound by S2B1 with affinities in the 1-3 nM range (Chiu et al, 2001).…”

Engineered Antibodies for Monitoring of Polynuclear Aromatic Hydrocarbons

“…In many small-molecule immunoassays, cross-reactivity can be modulated to some extent by using different haptens as competitors. [33][34][35][36][37][38] The relative binding patterns for BaP and other PAHs differed somewhat when different hapten conjugates were used. However, significant structural overlap blurred the differences in PAH size.…”

Effect of lipid composition on phospholipase A2‐catalyzed membrane leakage in immobilized liposomes: Sensitization for polychlorinated biphenyls detection with antibody affinity column tandem with fluorescent liposome column

“…The enzyme-linked immunosorbent assay offered rapid and sensitive characterizations for PCB contamination, and achieved detec-tion level of 5 mg PCB /mL from soil sample or 1 ng/mL from liquid sample [4,5]. Recently, dye entrapped liposomes have been used for signal amplification in competitive immunoassays [6][7][8]. A high concentration of fluorescent dye can be entrapped in liposomes and a small amount of the dye released upon the antibody binding will result in a fluorescent signal which can be detected.…”