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Brazhnikov G, Smolnikov E, Litovkina A, Jiang T, Shatilov A, Tulaeva I, Tulaev M, Karaulov A, Poroshina A, Zhernov Y, Focke‐Tejkl M, Weber M, Akinfenwa O, Elisyutina O, Andreev S, Shilovskiy I, Shershakova N, Smirnov V, Fedenko E, Lepeshkova TS, Beltyukov EC, Naumova VV, Kundi M, Khaitov M, Wiedermann U, Valenta R, Campana R. Natural human Bet v 1-specific IgG antibodies recognize non-conformational epitopes whereas IgE reacts with conformational epitopes. Allergy 2023; 78:3136-3153. [PMID: 37701941 PMCID: PMC10952721 DOI: 10.1111/all.15865] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 07/06/2023] [Accepted: 07/12/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND The nature of epitopes on Bet v 1 recognized by natural IgG antibodies of birch pollen allergic patients and birch pollen-exposed but non-sensitized subjects has not been studied in detail. OBJECTIVE To investigate IgE and IgG recognition of Bet v 1 and to study the effects of natural Bet v 1-specific IgG antibodies on IgE recognition of Bet v 1 and Bet v 1-induced basophil activation. METHODS Sera from birch pollen allergic patients (BPA, n = 76), allergic patients without birch pollen allergy (NBPA, n = 40) and non-allergic individuals (NA, n = 48) were tested for IgE, IgG as well as IgG1 and IgG4 reactivity to folded recombinant Bet v 1, two unfolded recombinant Bet v 1 fragments comprising the N-terminal (F1) and C-terminal half of Bet v 1 (F2) and unfolded peptides spanning the corresponding sequences of Bet v 1 and the apple allergen Mal d 1 by ELISA or micro-array analysis. The ability of Bet v 1-specific serum antibodies from non-allergic subjects to inhibit allergic patients IgE or IgG binding to rBet v 1 or to unfolded Bet v 1-derivatives was assessed by competition ELISAs. Furthermore, the ability of serum antibodies from allergic and non-allergic subjects to modulate Bet v 1-induced basophil activation was investigated using rat basophilic leukaemia cells expressing the human FcεRI which had been loaded with IgE from BPA patients. RESULTS IgE antibodies from BPA patients react almost exclusively with conformational epitopes whereas IgG, IgG1 and IgG4 antibodies from BPA, NBPA and NA subjects recognize mainly unfolded and sequential epitopes. IgG competition studies show that IgG specific for unfolded/sequential Bet v 1 epitopes is not inhibited by folded Bet v 1 and hence the latter seem to represent cryptic epitopes. IgG reactivity to Bet v 1 peptides did not correlate with IgG reactivity to the corresponding Mal d 1 peptides and therefore does not seem to be a result of primary sensitization to PR10 allergen-containing food. Natural Bet v 1-specific IgG antibodies inhibited IgE binding to Bet v 1 only poorly and could even enhance Bet v 1-specific basophil activation. CONCLUSION IgE and IgG antibodies from BPA patients and birch pollen-exposed non-sensitized subjects recognize different epitopes. These findings explain why natural allergen-specific IgG do not protect against allergic symptoms and suggest that allergen-specific IgE and IgG have different clonal origin.
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Affiliation(s)
- Georgii Brazhnikov
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Evgenii Smolnikov
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
- Department of Immunology, Institute of MedicineRUDN UniversityMoscowRussia
| | - Alla Litovkina
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
- Department of Immunology, Institute of MedicineRUDN UniversityMoscowRussia
| | - Tianchi Jiang
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Artem Shatilov
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Inna Tulaeva
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
- Laboratory of Immunopathology, Department of Clinical Immunology and AllergologyI.M. Sechenov First Moscow State Medical University (Sechenov University)MoscowRussia
| | - Mikhail Tulaev
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Alexander Karaulov
- Laboratory of Immunopathology, Department of Clinical Immunology and AllergologyI.M. Sechenov First Moscow State Medical University (Sechenov University)MoscowRussia
| | - Alina Poroshina
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Yury Zhernov
- F. Erismann Institute of Public HealthI.M. Sechenov First Moscow State Medical University (Sechenov University)MoscowRussia
| | - Margarete Focke‐Tejkl
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
- Karl Landsteiner University of Health SciencesKremsAustria
| | - Milena Weber
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Oluwatoyin Akinfenwa
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Olga Elisyutina
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
- Department of Immunology, Institute of MedicineRUDN UniversityMoscowRussia
| | - Sergey Andreev
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Igor Shilovskiy
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Nadezhda Shershakova
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Valeriy Smirnov
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | - Elena Fedenko
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
| | | | - Evgeny Cronidovich Beltyukov
- Department of Faculty Therapy, Endocrinology, Allergology and ImmunologyUral State Medical UniversityYekaterinburgRussia
| | - Veronika Victorovna Naumova
- Department of Faculty Therapy, Endocrinology, Allergology and ImmunologyUral State Medical UniversityYekaterinburgRussia
| | - Michael Kundi
- Institute for Hygiene and Applied Immunology, Center for Public HealthMedical University of ViennaViennaAustria
| | - Musa Khaitov
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
- Pirogov Russian National Research Medical UniversityMoscowRussia
| | - Ursula Wiedermann
- Institute for Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
| | - Rudolf Valenta
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
- National Research Center Institute of Immunology Federal Medical‐Biological Agency of RussiaMoscowRussia
- Laboratory of Immunopathology, Department of Clinical Immunology and AllergologyI.M. Sechenov First Moscow State Medical University (Sechenov University)MoscowRussia
- Karl Landsteiner University of Health SciencesKremsAustria
| | - Raffaela Campana
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and ImmunologyMedical University of ViennaViennaAustria
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