SELECTIVE RECOGNITION OF SUBSTITUTED CHRYSENE-DIOL EPOXIDE-2-DNA ADDUCTS BY ANTISERUM PREPARED AGAINST DNA-ADDUCTS OF BENZO[C]-PHENANTHRENE-DIOL EPOXIDE-2

Polyclonal antiserum prepared against DNA that was modified with racem ic benzo[c]phenanthrene-3,4-diol-1,2-epoxide-2 (B[c]PhDE-2; benzylic h ydroxyl and epoxide oxygen trans) was characterized for specificity of antigen recognition. Previous studies have demonstrated that the anti sera stereoselectively recognized B[c]PhDE-2-DNA and failed to recogni ze DNA modified with racemic benzo [c]phenanthrene-3,4-diol-1,2-epoxid e-1 (B[c]PhDE-1-DNA, benzylic hydroxyl and epoxide oxygen cis), benzo[ a]pyrene-7,8-diol-9, 10-epoxide-2-DNA (B[a]PDE-2-DNA) and methylbenz[a ]anthracene-3,4-diol-1,2-epoxide-1-DNA (DMBADE-1-DNA). DNA samples mod ified by diol-epoxide-2 diastereomers of several hydrocarbons were tes ted in competitive ELISA assays utilizing B[c]PhDE-2-DNA (270 fmol add ucts per well). DNA modified with racemic diol-epoxide-2 of various su bstituted chrysenes (including chrysene, benzo[g]chrysene (B[g]C), 6-m ethylchrysene (6-MeC), and 5-methychrysene (5-MeC), gave 50% inhibitio n of antisera binding at significantly higher concentrations (5 to 7-f old) than the parent B[c]PhDE-2-DNA or 5,6-diMeCDE-DNA. DNA modified w ith 5, 7-dimethylchryseneDE-2 (5,7-diMeCDE-2) and dibenzo[a,l]pyreneDE -2 (DB[a,l] PDE-2) required 20 and > 100-fold greater levels of adduct s to give 50% inhibition. Results with B[c]Ph, 5,6-diMeC, chrysene, 6- MeC and 5-MeC diol epoxide-2-DNA indicate that substitution of a methy l group in the vicinity of the bay-region of the PAH-molecule had limi ted effects on antigen recognition by this antiserum. However, the add ition of a ring or methyl group remote from the diol epoxide moiety, a s in DB[a,l] PDE-2-DNA or 5,7-diMeCDE-2-DNA greatly decreased antigen recognition. The ability of this antiserum to recognize DNA adducts of a particular class of polycyclic aromatic hydrocarbons will be useful for studies of their contribution to the DNA-binding that results fro m exposure to complex environmental mixtures.