Coupling of DNA to bead type cellulose as immunoadsorbent

In order to remove the anti-DNA antibody from the blood of patients with sy stematic lupus erythematosus (SLE), DNA immunoadsorbent was prepared by cou pling calf thymus DNA to epichlorohydrin-activated cellulose beads, The met hods and conditions for activation of carrier beads, DNA coupling and adsor ption with patient's plasma were investigated. The activation level was fou nd to be dependent on the NaOH concentration, amount of offered epichlorohy drin and the molar ratio between NaOH and epichlorohydrin. One milliliter o f cellulose beads was activated by incubation with 0. 5 mt of epichlorohydr in and 2. 0 mt of 2. 0-3. 0 mol/L NaOH solution at 40 degreesC for 2 h, and the activation level was 60-100 mu mol/mL beads. DNA coupling was found to be strongly dependent on temperature and pH. The optimal coupling conditio ns were 0. 1 mol/L Tris-HCl buffer, pH 7. 9-8. 0 and 70-90 degreesC. High a ctivation level, high DNA concentration and long reaction time were also re quired. Under the optimal condition, 2. 0-3. 0 mg of DNA could be coupled t o 1. 0 mt of cellulose beads. In vitro adsorption tests showed that incubat ion of 1. 0 mt of adsorbent with 3. 0 mt of plasma could remove 40%-70% of anti-DNA antibody from the plasma.