Effect of Irreversible Adsorbents on the Dissociation of the Antigen-Antibody Complexes

Abstract

During separation of antibody-bound from free antigen by sequestrating the latter on adsorbents, a dissociation of antigen- antibody complexes may occur. This yields an amount of antigen adsorbed which is higher than the amount of the free antigen present in the equilibrium mixture. A study of the dissociation of the antigen-antibody complexes was performed, using angiotensin II and dextran-coated charcoal as a model. The kinetic analysis of the adsorption curves allowed two well-separated classes of sites to be distinguished in terms of dissociation constant for the two antisera considered, and the actual composition of the incubated mixture to be quantitated. The experimental data demonstrated as well the importance of optimizing the separation step when setting-up a radioimmunoassay procedure.

Key words

Antigen-Antibody Complex - Free Antigen - Antiserum Heterogeneity - Irreversible Adsorbent