Binding characteristics of SLE anti-DNA autoantibodies to modified DNA analogues.

Native calf thymus DNA was modified with furocoumarins and reactive oxygen species (ROS). The modifications were probed by UV & Fluorescence spectroscopy, thermal denaturation and hydroxyapatite chromatography. In CD spectroscopy changes in the ellipticity of the DNA molecule were observed as a result of modification. The binding specificity of naturally occurring anti-DNA antibodies with modified DNA molecules was assessed by ELISA and quantitative precipitin titration. The affinity of anti-DNA antibodies for modified conformers was found to be quite high.