Immunological detection and quantitation of DNA adducts formed by 4-aminoazobenzene species in vivo.

Antibodies to 3-methoxy-4-aminoazobenzene (3-MeO-AAB) and 2-methoxy-4-aminoazobenzene (2-MeO-AAB) DNA adducts were raised in rabbits against in vitro-adducted DNA samples. The enzyme-linked immunosorbent assay (ELISA) was used to determine the sensitivity and specificity of these antibodies. They proved highly specific for the modified DNA used as the immunogen, but cross-reacted with each other. Moreover, they showed cross reactivity with DNA modified by 4-(o-tolylazo)-o-toluidine, but not by other carcinogens, such as 4-aminobiphenyl or 4-nitroquinoline 1-oxide. The 50% inhibition level of antibody binding in the competitive ELISA was at 10-20 fmol of modified base per assay (equivalent to 1-2 adducts per 10(6) bases). Immunohistochemical staining indicated that these antibodies bind specifically to nuclear components of the liver in rats given either 3-MeO-AAB or 2-MeO-AAB at the dose of 50 mg/kg body weight.

3‐methoxy‐4‐aminoazobenzene

2‐methoxy‐4‐aminoazobenzene

4‐(o‐tolylazo)‐o‐toluidine

4‐nitroquinoline 1‐oxide

4‐aminobiphenyl

3,2′‐dimethyl‐4‐aminobiphenyl

2‐amino‐6‐methyldipyrido[1,2‐a: 3′, 2′‐d]imidazole

2‐ amino‐ dipyrido [1,2‐a: 3′, 2′d] imidazole

2‐acetylaminofluorene

enzyme‐linked immunosorbent assay