Detection of DNA damage in cells exposed to ionizing radiation by use of anti-single-stranded DNA monoclonal antibody

An immunochemical method has been developed for quantitative detection of DNA damage in mammalian cells (V79) based on the binding of a monoclonal antibody to single-stranded DNA. The technique is based upon the determination of the percentage single-strandedness resulting from the time-dependent partial unwinding of cellular DNA under alkaline conditions. The method is rapid, does not require radioactive labelling of DNA or physical separation of single- from double-stranded molecules, is sufficiently sensitive to detect damage induced by 1 Gy of ionizing radiation and needs only small numbers of cells. The usefulness of the technique was demonstrated in a study of the induction of DNA damage and its repair in cultured Chinese hamster cells and in human white blood cells after exposure to 60Co-γ-rays, and in white blood cells and bone marrow cells of X-irradiated mice. A dose-related DNA unwinding was observed and repair of DNA lesions was observed up to 60 min after irradiation. (author)