Immunosorbent consisting of DNA immobilized on oxirane-activated sepharose

The preparation of adsorbents for DNA antibodies is described. The degree of immobilization of native DNA on Sepharoses activated with epichlorohydrin or bisoxirane was investigated as a function of pH, temperature, time, concentration of DNA, and oxirane content in the supports. The maximum amount of DNA bound was obtained after 8 h at 40-50 degrees C at pH 11-11.5. The amount bound was increased by raising either the concentration of DNA or the oxirane content of the supports, and could reach 300 mg/g dry support. The immobilized DNA was applied to the adsorption of DNA antibodies using either commercial human serum with anti-native DNA activity or the sera of patients with systemic lupus erythematosus. The amount of antibody adsorbed depended on the amount of DNA. The thermal stability of the immobilized DNA was also examined. After heating at 80 degrees C, the leakage of DNA was slight and the adsorption of antibodies was not affected.