Genetic engineering of hybrids of major mite allergens of Dermatophagoides pteronyssinus and evaluation of their potential as vaccines for immunotherapy

Abstract

Natural extract-based allergy vaccines contain variable amounts of individual allergens, some potentially exhibiting low immunogenicity. In an approach addressing both problems and polysensitization, major mite allergens from Dermatophagoides pteronyssinus (Der p 1, 2, 5 and 7) were incorporated into hybrids (Der p 1-2, Der p 7-5) and expressed under denaturing conditions. These proteins showed lower IgE-binding than wildtype allergens. Rabbits immunized with either hybrid developed IgG that bound corresponding individual allergens and inhibited binding to sensitized patient IgE. Notably, inhibition by Der p 7-5-induced IgG was comparable to that by component allergens. Comparing with Der p 1 similarly expressed under denaturing conditions, incorporation of the allergen into the hybrid enhanced its immunogenicity and the IgG repertoire seemed broader, showing greater inhibition. Finally, mice immunization with native Der p 1 and the recombinant expressed in denaturing condition illustrated that maintaining vaccine conformation is important for allergens with predominantly conformational epitopes.