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
