Development of a DNA immunoadsorbent: Coupling DNA on sepharose 4FF by an efficient activation method

To remove anti-DNA antibodies from a patient's plasma with systemic lupus e rythematosus (SLE), a DNA immunoadsorbent was developed by covalently coupl ing calf thymus DNA on activated Sepharose 4FF. Sepharose 4FF was activated with 5-norbornene-2,3-dicarboximido carbonochloridate (Cl-CO-ONB), which w as proven to be a very effective method for preparation of affinity chromat ographic adsorbents. The activation was carried out in dry acetone using 4- (dimethylamine)pyridine (DMAP) and triethylamine (TEA) as catalysts at 4 de greesC or at room temperature. The coupling of DNA to the activated support was investigated as a function of pH, temperature, time, concentration of DNA, and activation level. It was found that the pH for optimal coupling is 3.0, and the amount of coupled DNA increases with an increase either in th e concentration of DNA or the activation level. The maximum amount of coupl ed DNA could reach 1.0 mg DNA/ml support. The incubation of 5 to 20 ml of S LE plasma with 1.0 ml of adsorbent resulted in an 80 to 90% decline in the anti-DNA antibody level. Nonspecific adsorption for normal IgG and total pr otein is less than 15%.