Detection of Oxidative DNA Base Damages

Abstract

Antibodies to a variety of oxidized DNA bases have been generated in a number of laboratories including our own (see Table I). Most of these antibodies have been elicited using protein-conjugated haptens of interest. In general, the antibodies have reasonable affinity such that appropriate sensitivity in the various assays can be achieved. The difficulty with antibodies that recognize oxidized DNA bases is that the oxidized bases do not differ largely from their unoxidized derivatives. Thus, the specificity for detecting lesions in DNA must be high especially when one considers the low level of damaged compared to undamaged bases. Even if the sensitivity of the assay can be amplified, cross-reactivity of the antibody with the unoxidized base in DNA remains an obstacle to successful detection of low levels of the oxidized base. This particular problem is not seen as often when antibodies are elicited to the chemical adducts that have features that vary quite dramatically from the unadducted base. An additional consideration is that the lesion must be stable to the procedures used during preparation of the immunogen and during DNA denaturation. The latter is usually necessary since the antibodies often do not recognize the lesion as well in duplex DNA. Despite these shortcomings, antibodies to oxidized bases have been effectively utilized to detect these lesions in oxidized or ionizing radiation-treated DNA in vitro.