Quantitation of Aflatoxin B,-modified DMA Using Monoclonal Antibodies1

Five monoclonal antibodies were obtained after fusion of mouse P3 x 63 myeloma cells with spleen cells isolated from BALB/c mice that had been immunized with aflatoxin B,-adducted DMA complexed with methylated bovine serum albumin. Selected hybridomas were found to produce monoclonal anti bodies specific for modified DMA containing both the 2,3dihydro-2-(/V7-guanyl)-3-hydroxyaflatoxin B, and the putative 2,3-dihydro-2-(A/5-formyl-2', 5', 6'-triamino-4'-oxo-A/5-pyrimidyl)-3-hydroxyaflatoxin B,, suggesting that these DNA adducts share a common antigenic determinant. Enzyme immunoassay conditions using these monoclonal antibodies were optimized, and DNA isolated from the livers of rats given dosages of aflatoxin B! ranging from 0.01 to 1.0 mg aflatoxin B, per kg body weight was tested. A level of modification in DNA of 1 aflatoxin Bi residue per 1,355,000 nucleotides can be quanti tatively measured. Monoclonal antibodies will be useful probes for studying the molecular interactions of aflatoxin Bi with DNA and the occurrence of aflatoxin B,:DNA adducts in tissues and cells of humans exposed to this environmental carcinogen.