Chimeras of Bet v 1 and Api g 1 reveal heterogeneous IgE responses in patients with birch pollen allergy

• Published in: Journal of allergy and clinical immunology Vol. 134; no. 1; pp. 188 - 194
• Main Authors: Gepp, Barbara, Lengger, Nina, Bublin, Merima, Hemmer, Wolfgang, Breiteneder, Heimo, Radauer, Christian
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.07.2014; Elsevier; Elsevier Limited; Mosby
• Subjects: Adolescent; Adult; Aged; Allergens - chemistry; Allergens - genetics; Allergens - immunology; Allergies; Allergy and Immunology; Amino Acid Sequence; Animals; Antibody Specificity; Antigens, Plant - chemistry; Antigens, Plant - genetics; Antigens, Plant - immunology; Api g 1.0101; Bet v 1.0101; Binding sites; Binding Sites, Antibody; Biological and medical sciences; birch pollen allergy; Child; Chimera - genetics; Chimera - immunology; chimera-based technology; Epitopes - chemistry; Epitopes - genetics; Epitopes - immunology; Escherichia coli - genetics; Escherichia coli - metabolism; Female; Food; Food allergies; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Genetic Heterogeneity; Humans; IgE epitope mapping; Immune Sera - chemistry; Immunoglobulin E - chemistry; Immunoglobulin E - genetics; Immunoglobulin E - immunology; Immunopathology; Immunotherapy; Male; Mechanisms of Allergy and Clinical Immunology; Medical sciences; Middle Aged; Molecular Sequence Data; Pathogenesis; patient-specific IgE repertoire; Patients; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - immunology; Pollen; Protein Binding; Proteins; Quality of life; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Retrospective Studies; Rhinitis, Allergic, Seasonal - genetics; Rhinitis, Allergic, Seasonal - immunology; Rhinitis, Allergic, Seasonal - pathology; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Sequence Homology, Amino Acid; Studies; Sweden; Austria; Bet v 1.0101; birch pollen allergy; Api g 1.0101; chimera-based technology; IgE epitope mapping; patient-specific IgE repertoire; Allergy; Antigenic determinant; Insecta; Apidae; Immunology; Technology; Apoidea; Dicotyledones; Angiospermae; Pollen; Immunologic repertoire; Betulaceae; Aculeata; Human; Cartography; Immunopathology; Specific IgE; Apis; Arthropoda; Spermatophyta; Chimerism; Hymenoptera; Invertebrata; Betula; Chimera
• ISSN: 0091-6749; 1097-6825; 1097-6825
• DOI: 10.1016/j.jaci.2013.12.1073

Characterization of IgE-binding epitopes of allergens and determination of their patient-specific relevance is crucial for the diagnosis and treatment of allergy. We sought to assess the contribution of specific surface areas of the major birch pollen allergen Bet v 1.0101 to binding IgE of individual patients. Four distinct areas of Bet v 1 representing in total 81% of its surface were grafted onto the scaffold of its homolog, Api g 1.0101, to yield the chimeras Api-Bet-1 to Api-Bet-4. The chimeras were expressed in Escherichia coli and purified. IgE binding of 64 sera from Bet v 1–sensitized subjects with birch pollen allergy was determined by using direct ELISA. Specificity was assessed by means of inhibition ELISA. rApi g 1.0101, Api-Bet-1, Api-Bet-2, Api-Bet-3, and Api-Bet-4 bound IgE from 44%, 89%, 80%, 78%, and 48% of the patients, respectively. By comparing the amount of IgE binding to the chimeras and to rApi g 1.0101, 81%, 70%, 75%, and 45% of the patients showed significantly enhanced IgE binding to Api-Bet-1, Api-Bet-2, Api-Bet-3, and Api-Bet-4, respectively. The minority (8%) of the sera revealed enhanced IgE binding exclusively to a single chimera, whereas 31% showed increased IgE binding to all 4 chimeras compared with rApi g 1.0101. The chimeras inhibited up to 70% of IgE binding to rBet v 1.0101, confirming the specific IgE recognition of the grafted regions. The Bet v 1–specific IgE response is polyclonal, and epitopes are spread across the entire Bet v 1 surface. Furthermore, the IgE recognition profile of Bet v 1 is highly patient specific.