HAPTEN SYNTHESIS AND ANTIBODY DEVELOPMENT FOR POLYCHLORINATED DIBENZO-P-DIOXIN IMMUNOASSAYS

This paper reports the synthesis of haptens and the generation and pre liminary evaluation of polyclonal antibodies for the detection of diox ins such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) by ELISA (enzym e-linked immunosorbent assay). These novel haptens contain unsaturatio n between the halogenated dibenzo-p-dioxin ring system and the protein to which it is conjugated, presenting a rigid handle structure. The s ubstitution pattern is identical with or similar to that of TCDD (i.e. , 2,3,7,8- or 1,2,3,7,8-). Finally, the haptens lack polar groups for hydrogen bonding. In direct binding assays using the new polyclonal an tibodies there was excellent recognition of hapten-protein conjugates, including recognition of those hapten conjugates that were not used a s immunogens (i.e., assay systems heterologous in hapten structure). T hese haptens do elicit selective immune responses in rabbits. Their ev aluation in an ELISA format demonstrated the usefulness of these hapte ns for the detection of dioxins. An IC50 of 0.8 ng/well (16 ng/mL) was observed for an unoptimized system that used 2,3,7-trichloro-8-methyl dibenzo-p-dioxin as an analytical surrogate standard.