Recombinant PreS‐fusion protein vaccine for birch pollen and apple allergy

Background IgE cross‐sensitization to major birch pollen allergen Bet v 1 and pathogenesis‐related (PR10) plant food allergens is responsible for the pollen‐food allergy syndrome. Methods We designed a recombinant protein, AB‐PreS, consisting of non‐allergenic peptides derived from the IgE‐binding sites of Bet v 1 and the cross‐reactive apple allergen, Mal d 1, fused to the PreS domain of HBV surface protein as immunological carrier. AB‐PreS was expressed in E. coli and purified by chromatography. The allergenic and inflammatory activity of AB‐PreS was tested using basophils and PBMCs from birch pollen allergic patients. The ability of antibodies induced by immunization of rabbits with AB‐PreS and birch pollen extract‐based vaccines to inhibit allergic patients IgE binding to Bet v 1 and Mal d 1 was assessed by ELISA. Results IgE‐binding experiments and basophil activation test revealed the hypoallergenic nature of AB‐PreS. AB‐PreS induced lower T‐cell activation and inflammatory cytokine production in cultured PBMCs from allergic patients. IgG antibodies induced by five injections with AB‐PreS inhibited allergic patients' IgE binding to Bet v 1 and Mal d 1 better than did IgG induced by up to 30 injections of six licensed birch pollen allergen extract‐based vaccines. Additionally, immunization with AB‐PreS induced HBV‐specific antibodies potentially protecting from infection with HBV. Conclusion The recombinant AB‐PreS‐based vaccine is hypoallergenic and superior over currently registered allergen extract‐based vaccines regarding the induction of blocking antibodies to Bet v 1 and Mal d 1 in animals. We designed a vaccine consisting of peptides derived from IgE epitopes of birch and apple allergens fused with HBV‐derived PreS. Aluminum hydroxide‐adsorbed AB‐PreS induces IgG antibodies specific for Bet v 1, Mal d 1, and HBV. IgG antibodies induced by AB‐PreS inhibit IgE binding of allergic patients IgE to Bet v 1 and Mal d 1 better than extract‐based vaccines. Anti‐PreS IgG may protect against HBV infection.Abbreviations: Ab‐PreS, recombinant protein, consisting of non‐allergenic peptides derived from the IgE binding sites of Bet v 1 and Mal d 1, fused to the PreS domain of HBV surface protein as immunological carrier; Bet v 1, major birch pollen allergen; HBV, hepatitis B virus; Ig, immunoglobulin; Mal d 1, cross‐reactive apple allergen; OD, optical density.