Genetic engineering of trimers of hypoallergenic fragments of the major birch pollen allergen, Bet v 1, for allergy vaccination

• Published in: Vaccine 2011-03, Vol.29 (11), p.2140-2148
• Main Authors: Vrtala, Susanne, Fohr, Monika, Campana, Raffaela, Baumgartner, Christian, Valent, Peter, Valenta, Rudolf
• Format: Article
• Language: English
• Subjects: Allergens; Allergens - genetics; Allergens - immunology; Allergies; Allergy; Allergy and Immunology; Animals; Antibody Formation; Antibody Specificity; Antigens, Plant - genetics; Antigens, Plant - immunology; Applied microbiology; Bet v 1 antigen; Betula - immunology; Biological and medical sciences; Clinical trials; Cloning, Molecular; Data processing; Deoxyribonucleic acid; Derivatives; Desensitization, Immunologic; DNA; E coli; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Female; Fundamental and applied biological sciences. Psychology; Genetic Engineering; Humans; Hypersensitivity; Immunization; Immunogenicity; Immunoglobulin E; Immunoglobulin E - blood; Immunoglobulin E - immunology; Immunoglobulin G; Immunoglobulin G - blood; Immunoglobulin G - immunology; Immunotherapy; Mice; Mice, Inbred BALB C; Microbiology; Monomers; Oligomerization; Patients; Plasmids; Pollen; Pollen - immunology; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Rhinitis, Allergic, Seasonal - immunology; Rhinitis, Allergic, Seasonal - therapy; Studies; Vaccines; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects)
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2010.12.080

Abstract An immunotherapy trial performed in allergic patients with hypoallergenic recombinant fragments, comprising aa 1–74 and 75–160 of the major birch pollen allergen, Bet v 1, has indicated that the induction of allergen-specific IgG responses may be an important mechanism of this treatment. To investigate whether the immunogenicity of the rBet v 1 fragments can be increased, recombinant trimers of the fragments were produced. For this purpose, DNA trimers of rBet v 1 aa 1–74 as well as of rBet v 1 aa 75–160 were subcloned into expression plasmid pET 17b, expressed in Escherichia coli and purified. The fragments as well as the fragment trimers showed a reduced IgE-binding capacity and allergenic activity compared to rBet v 1 wildtype when tested in allergic patients. Both rBet v 1 aa 75–160 monomer and trimer induced high titers of allergen-specific IgG1 Abs in mice. Interestingly, rBet v 1 aa 1–74 trimer induced a much higher IgG1 response to rBet v 1 than rBet v 1 aa 1–74 monomer. Consequently, IgG Abs induced with the rBet v 1 aa 1–74 trimer inhibited birch pollen allergic patients’ IgE-binding 10-fold more efficiently than IgG Abs induced with the monomer. Our data show that the immunogenicity of allergy vaccines can be increased by oligomerization.