Latent immunization to produce high-affinity monoclonal antibodies to progesterone.

A simple immunization method to obtain high-affinity monoclonal antibodies to progesterone is described in this article. The method is based on the theory of affinity maturation. A long interval between antigen priming and booster ("latent immunization") permits an undisturbed completion of affinity maturation, resulting in the accumulation of memory B lymphocytes with high-affinity Ig receptors, and consequently, in a higher rate of hybridoma clones producing high-affinity antibody after cell fusion. Antibodies obtained after hyperimmunization and latent immunization are compared in a homologous, direct, competitive ELISA. The average numbers of high-affinity antibodies per fusion were 1.3 and 5.7 in the hyperimmunized and latent immunized groups, respectively. There was no significant difference in the specificities between the two immunization groups.