DEVELOPMENT OF MONOCLONAL-ANTIBODIES TO THE MALONDIALDEHYDE-DEOXYGUANOSINE ADDUCT, PYRIMIDOPURINONE

Malondialdehyde (MDA), an endogenous product of lipid peroxidation and prostaglandin biosynthesis, is mutagenic in bacterial and mammalian c ells and carcinogenic in rats. In order to determine whether MDA-modif ied bases are formed in nucleic acids in vivo, sensitive immunoassays to detect MDA-DNA and MDA-RNA adducts are being developed in our labor atory. Murine monoclonal antibodies reactive with the MDA-deoxyguanosi ne adduct -pentofuranosylpyrimido[1,2-alpha]purin-10(3H)-one (M(1)G-R) were prepared and characterized. Several MDA-modified nucleosides and deoxynucleosides and structural analogs were synthesized and characte rized and were compared as competitive inhibitors in enzymelinked immu nosorbent assays (ELISAs). Less than 5 fmol of M(1)G in MDA-modified D NA was detected in a direct ELISA, and antibody binding to the modifie d DNA was competitively inhibited by free M(1)G-dR. DNA from Salmonell a typhimurium treated with concentrations of MDA that induce reversion to histidine prototrophy was enzymatically digested, and M(1)G-dR was quantitated by competitive ELISA. Over a range of MDA concentrations from 10 to 40 mM, the level of M(1)G residues in bacterial DNA increas ed from 0.2 to 2.5/10(6) base pairs.