Immunochemical studies of DNA modified by cis-dichlorodiammineplatinum(II) in vivo and in vitro.

Two rabbits were immunized with native DNA modified in vitro by cis-dichlorodiammineplatinum(II) (cis-Pt). The interactions between the antiserum and several natural and synthetic nucleic acids were studied primarily by radioimmunoassays. Native DNA's modified by platinum compounds with labile groups in the cis position are recognized by the antiserum. No cross-reaction is found with native DNA's substituted by other platinum compounds [trans-dichlorodiammineplatinum(II), cis-diamminotetrachloroplatinum(IV), and chlorodiethylenetriamminoplatinum(II)] and with natural and synthetic modified polyribonucleotides. cis-Pt-modified oligodeoxyribonucleotides and enzymatically hydrolyzed cis-Pt-modified native DNA do not bind to the antiserum. cis-Pt-modified double-stranded synthetic polydeoxyribonucleotides are either hardly recognized or not recognized at all. The antiserum recognized a modified double-stranded helix in DNA which is not formed in several modified synthetic DNA's and RNA's. At least two different antigenic determinants are present in cis-Pt-modified DNA at a ratio of cis-Pt to bases equal to 0.05. Finally, the antiserum does not react with in vivo cis-Pt-modified DNA.