Immune Response to 17β-Estradiol Involved in Polymer Gels: Antigen Specificity and Affinity of Hybridoma Clones

The immunogenic properties of 17β-estradiol, immobilized in negatively charged polymer gels, were investigated, and the specificity of antibodies produced was analyzed. The polymer gels developed were composed of a hydrophobic estradiol core surrounded by hydrophilic polyanions as corona. As an immunogen, it was conceived to function via a dual mode, that is as a hapten-delivery system (prolongation effect) and as a polyelectrolyte adjuvant. Polymer gels containing estradiol appeared to possess a high estradiol-specific immunogenicity even without the addition of traditional adjuvants. A comparative study of estradiol trapped in polymer gels versus estradiol conjugated to bovine serum albumin (BSA.E) + Incomplete Freund's Adjuvant (IFA) mixtures revealed similar immunogenic properties in terms of induction of specific antibodies. Following a short immunization procedure based on the use of 17 β-estradiol immobilized in polymer gels, we developed 10 specific monoclonal antibodies with K_d values ranging between 1.2 × 10^-7 and 8 × 10^-8 M.