Immunoaffinity chromatography utilizing monoclonal antibodies. Factors which influence antigen-binding capacity

Area of Science:

• Bioconjugation Chemistry
• Immunoadsorbent Development
• Protein Immobilization

Background:

• Monoclonal antibodies (mAbs) are vital tools in diagnostics and therapeutics.
• Immobilizing mAbs onto solid supports, like Sepharose, creates immunoadsorbents for various applications.
• Optimizing the coupling process is essential to maximize the functional capacity of these immunoadsorbents.

Purpose of the Study:

• To investigate the impact of coupling conditions on the antigen-binding capacity of monoclonal antibodies immobilized on Sepharose.
• To compare different coupling chemistries for mAb immobilization.
• To determine optimal conditions for maximizing immunoadsorbent performance.

Main Methods:

• Monoclonal antibody coupling to Sepharose using cyanogen bromide (CNBr) activation.
• Varying CNBr activation levels and coupling reaction pH.
• Evaluating antigen-binding capacity of the resulting immunoadsorbents.
• Comparing CNBr activation with N-hydroxysuccinimide (NHS) ester linkage for antibody coupling.

Main Results:

• The extent of CNBr activation and reaction pH significantly affected the rate of antibody coupling.
• Terminating antibody coupling at 80-90% covalent immobilization resulted in minimal loss of antigen-binding capacity.
• Complete antibody coupling (100%) led to a significant decrease in antigen-binding capacity.
• NHS ester linkage resulted in approximately half the antigen-binding capacity compared to CNBr activation.
• High antibody concentrations (up to 13 mg/ml) could be used without steric hindrance.

Conclusions:

• Optimizing the degree of antibody immobilization is critical for maximizing immunoadsorbent antigen-binding capacity.
• Partial coupling (80-90%) is preferable to complete coupling for CNBr-activated Sepharose.
• CNBr activation is a more effective method than NHS ester linkage for achieving high antigen-binding capacity with monoclonal antibodies on Sepharose.
• High antibody loading is feasible without compromising functionality, suggesting efficient use of the resin.