HAPTEN SYNTHESIS AND PRODUCTION OF RABBIT ANTIBODIES WITH REACTIVITY TO DDT AND ITS METABOLITES FOR THE DEVELOPMENT OF AN IMMUNOASSAY

Diamino derivatives of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) and its metabolites 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethe ne (DDE), and 2,2-bis(p-chlorophenyl) acetic acid (DDA) were synthesis ed for use as haptens in the development of an immunoassay. The hapten s were conjugated to protein molecules by the diazo reaction and used to produce rabbit antibodies. Immunoelectrophoresis and enzyme-linked immunoadsorbent assay (ELISA) demonstrated the presence of anti-hapten antibodies. The specificity of these antibodies to DDT and its metabo lites was established by inhibition ELISA. The minimum concentrations required for 50% inhibition were as follows: op'DDT, 180 ng mL(-1) pp DDT, 120 ng mL(-1); pp'DDD [1,1-dichloro-2.2 bis (p-chlorophenyl) etha ne] > 1,000 ng mL(-1); pp'DDE, 218 ng mL(-1) and pp'DNA, 360 ng mL(-1) using antibodies to the nearest analogue of haptens. The differential cross reactivity with analogues indicates that the epitope presumably include alkyl group besides the phenyl portion of the molecule. The c ompetitive inhibition ELISA can be used for a multiresidue analysis of DDT and its metabolites.