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

Area of Science:

• Biochemistry
• Immunology
• Materials Science

Background:

• Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of anti-DNA antibodies.
• Removing these antibodies from patient plasma could be a therapeutic strategy for SLE.
• Affinity chromatography offers a method for targeted removal of specific antibodies.

Purpose of the Study:

• To develop and characterize a DNA immunoadsorbent for the removal of anti-DNA antibodies from SLE patient plasma.
• To optimize the coupling of DNA to an activated Sepharose support for enhanced binding capacity.
• To evaluate the efficacy and specificity of the developed immunoadsorbent in reducing anti-DNA antibody levels.

Main Methods:

• Covalent coupling of calf thymus DNA to Sepharose 4FF activated with 5-norbornene-2,3-dicarboximido carbonochloridate (Cl-CO-ONB).
• Optimization of DNA coupling conditions including pH, temperature, time, DNA concentration, and activation level.
• Incubation of SLE patient plasma with the DNA immunoadsorbent and measurement of anti-DNA antibody reduction.

Main Results:

• The optimal pH for DNA coupling was determined to be 3.0.
• Maximum DNA coupling capacity reached 1.0 mg DNA/ml of support.
• Incubation with the immunoadsorbent reduced anti-DNA antibody levels by 80-90% in SLE plasma.
• Nonspecific adsorption of normal IgG and total protein was minimal (<15%).

Conclusions:

• A highly effective DNA immunoadsorbent was successfully prepared using activated Sepharose 4FF.
• The developed method demonstrates significant potential for the extracorporeal removal of anti-DNA antibodies in SLE treatment.
• This approach offers a promising avenue for managing autoimmune diseases driven by specific autoantibodies.