Immunological tolerance to allergenic protein determinants: a therapeutic approach for selective inhibition of IgE antibody production.

Administration of stable conjugates prepared by coupling protein antigens such as ovalbumin or antigen E of ragweed extract to the synthetic random copolymer of D-glutamic acid and D-lysine (D-GL) is effective in inducing a state of long-lasting, antigen-specific immunological tolerance in experimental animals. A striking aspect of the tolerance induced by protein-D-GL conjugates is the remarkable selectivity of the tolerance for antibody responses of the IgE class. Protein-D-GL conjugates of either type were capable of inducing such tolerance both in unsensitized and in previously sensitized animals when administered in appropriate doses. Comparable doses of unconjugated proteins were likewise capable of suppressing IgE antibody production, although the duration of suppression in these cases was significantly less than that observed with protein-D-GL conjugates. If such conjugates act in man as they do in experimental animals, they could be of great value as therapeutic agents in selectively diminishing IgE antibody production while sparing antibody production in the IgG class.