Suppression of reaginic antibodies with modified allergens. I. Reduction in allergenicity of protein allergens by conjugation to polyethylene glycol.

The conjugates of ovalbumin (OA) and of the nondialysable constitutents of the aqueous extract of ragweed pollen (RAG) with polyethylene glycols of molecular weights of 6,000 or 20,000 (PEG6 or PEG20) were shown to be nonantigenic, nonallergenic and nonimmunogenic. Thus, the i.v. administration of OA-PEG and RAG-PEG conjugates into mice did not elicit antibodies to OA and RAG, respectively, and these conjugates were shown to suppress in an immunologically specific manner the capacity of these animals to mount primary as well as secondary IgE responses to sensitizing doses of dinitrophenylated OA or of RAG. Moreover, the Peg-modified antigens did not combine either in vitro or in vivo with IgE antibodies directed against the natural antigens. Hence, OA-PEG and RAG-PEG conjugates were incapable of triggering allergic reactions in animals possessing IgE antibodies to the unmodified antigens. These PEG-modified antigens were also shown to be tolerogenic.