Development and characterization of new monoclonal antibodies specific for coplanar polychlorinated biphenyls

Three polychlorinated biphenyls (PCBs) widely recognized as being among the most toxic, 3,3ʹ,4,4ʹ-tetrachlorobiphenyl (PCB77), 3,3ʹ,4,4ʹ,5-pentachlorobiphenyl (PCB126) and 3,3ʹ,4,4ʹ,5,5ʹ -hexachlorobiphenyl (PCB169) were each chemically substituted at the para position and attached to BSA via carboxylic acid spacers by the N-hydroxysuccinimide active ester method. The three resultant immunogens were used to stimulate immune responses in mice. Three of the resultant monoclonal antibodies were selected on the basis of target recognition and dimethyl sulfoxide tolerance and taken forward for further study and affinity measurement using a flow based immunoassay platform. The high sensitivity of the immunoassay platform used allows use of antibody concentrations below the Kd (=1/affinity) of the antibody offering ideal conditions to achieve Kd limited detection, the theoretical limit for the antibody used. One of the three antibodies exhibits high affinity binding to all three of the target PCBs, showing dynamic ranges in 2% (v/v) dimethyl sulfoxide of approximately 200 ng l^-1 to 14 (mu)g l^-1 for PCB77, 160 ng l^-1 to 6 (mu)g l^-1 for PCB126 and 22 ng l^-1 to 1.4 (mu)g l^-1 for PCB169. In addition, this antibody showed low cross reactivity to a panel of structurally similar PCBs, and to four common commercial mixtures of PCBs, Kanechlor 300, 400, 500 and 600. Data are included showing that the detection limit for PCB169 is not affected by the presence of a 50-fold excess of commercial PCB mixture Kanechlor 300.