Separation of high affinity hapten specific and crossreacting IgG populations

Abstract Antisera to an azohapten (2-(4′-carboxyphenylazo)-estriol) contains several IgG populations indistinguishable by their association constants for estriol—the homologue. However, significantly different relative affinities for a slightly altered hapten (estriol-3-sulfate) were shown. Immunosorption of crude antisera with an estriol-3-glucuronide-aminoethyl cellulose sorbant selectively removed antibody populations with highest affinity for haptens containing a blocked C-3 phenolic function. The residual antibody pool contained IgG with highest specificity for unaltered hapten.