Antibodies to DNA modified by the carcinogen N-acetoxy-N-2-acetylaminofluorene.

Several studies have shown that the carcinogen N-acetoxy-N-2-acetylaminofluorene (AAAF) reacts in vivo and in vitro with native DNA and that the DNA contains a major (80%) adduct N(deoxyguanosin8-yl)-acetylaminofluorene (dGuo8-AAF) and a minor (20%) adduct 3{deoxyguanosin-N2-yl)-acetylaminofluorene (dGuo-N2-AAF) (reviewed [1,2]). It has been shown that the major alteration induced by the fluorene ring is the creation of locally disorganized regions inside the double helical structure [3-81 . Methods sensitive enough to assay the regions of DNAmodified by a carcinogen at the levels of modification occuring in the ‘in vivo’ carcinogenesis experiments would be of great value. The immunological method has already been shown to be able to detect small modifications in DNA (see e.g. [9,10]). On the other hand, the study of the specificity of the antibodies can bring some knowledge on the conformation of the antigen. For these reasons, we have undertaken a study of the immunogenicity of native DNA after reaction with AAAF. In this paper, we show that native DNA slightly modified by AAAF can induce in rabbits the synthesis of specific antibodies which selectively recognize AAF-substituted DNA. A methods of purification of these antibodies is described. Also, the association constants for the binding of the antibodies and several ligands are reported.