Development of a novel Ara h 2 hypoallergen with no IgE binding or anaphylactogenic activity.
2S Albumins, Plant
/ genetics
Adolescent
Adult
Amino Acid Sequence
Anaphylaxis
/ genetics
Animals
Antigens, Plant
/ genetics
Basophils
/ immunology
Child
Child, Preschool
Epitopes
/ genetics
Female
Humans
Immunoglobulin E
/ immunology
Infant
Lymphocyte Activation
Male
Mice
Middle Aged
Mutation
T-Lymphocytes
/ immunology
Ara h 2
Peanut allergy
epitopes
hypoallergen
immunotherapy
mouse model
Journal
The Journal of allergy and clinical immunology
ISSN: 1097-6825
Titre abrégé: J Allergy Clin Immunol
Pays: United States
ID NLM: 1275002
Informations de publication
Date de publication:
01 2020
01 2020
Historique:
received:
06
02
2019
revised:
31
07
2019
accepted:
16
08
2019
pubmed:
17
9
2019
medline:
28
7
2020
entrez:
17
9
2019
Statut:
ppublish
Résumé
To date, no safe allergen-specific immunotherapy for patients with peanut allergy is available. Previous trials were associated with severe side effects. We sought to determine the relative importance of conformational and linear IgE-binding epitopes of the major peanut allergen Ara h 2 and to produce a hypoallergenic variant with abolished anaphylactogenic activity. Wild-type Ara h 2 and a mutant lacking the loops containing linear IgE epitopes were produced in insect cells. Conformational IgE epitopes were removed by unfolding these proteins through reduction and alkylation. IgE binding was tested by means of ELISA with sera from 48 Ara h 2-sensitized patients with peanut allergy. Basophil activation and T-cell proliferation were tested with blood samples from selected patients. Anaphylactogenic potency was tested by using intraperitoneal challenge of mice sensitized intragastrically to peanut extract. Patients' IgE recognized conformational and linear epitopes in a patient-specific manner. The unfolded mutant lacking both types of epitopes displayed significantly lower IgE binding (median ELISA OD, 0.03; interquartile range, 0.01-0.06) than natural Ara h 2 (median ELISA OD, 0.99; interquartile range, 0.90-1.03; P < .01). Basophil activation by unfolded mutant Ara h 2 was low (median area under the curve, 72 vs 138 for native wild-type Ara h 2; P < .05), but its ability to induce T-cell proliferation was retained. Unfolded mutants without conformational epitopes did not induce anaphylaxis in peanut-sensitized mice. By removing conformational and linear IgE epitopes, a hypoallergenic Ara h 2 mutant with abolished IgE binding and anaphylactogenic potency but retained T-cell activation was generated.
Sections du résumé
BACKGROUND
To date, no safe allergen-specific immunotherapy for patients with peanut allergy is available. Previous trials were associated with severe side effects.
OBJECTIVE
We sought to determine the relative importance of conformational and linear IgE-binding epitopes of the major peanut allergen Ara h 2 and to produce a hypoallergenic variant with abolished anaphylactogenic activity.
METHODS
Wild-type Ara h 2 and a mutant lacking the loops containing linear IgE epitopes were produced in insect cells. Conformational IgE epitopes were removed by unfolding these proteins through reduction and alkylation. IgE binding was tested by means of ELISA with sera from 48 Ara h 2-sensitized patients with peanut allergy. Basophil activation and T-cell proliferation were tested with blood samples from selected patients. Anaphylactogenic potency was tested by using intraperitoneal challenge of mice sensitized intragastrically to peanut extract.
RESULTS
Patients' IgE recognized conformational and linear epitopes in a patient-specific manner. The unfolded mutant lacking both types of epitopes displayed significantly lower IgE binding (median ELISA OD, 0.03; interquartile range, 0.01-0.06) than natural Ara h 2 (median ELISA OD, 0.99; interquartile range, 0.90-1.03; P < .01). Basophil activation by unfolded mutant Ara h 2 was low (median area under the curve, 72 vs 138 for native wild-type Ara h 2; P < .05), but its ability to induce T-cell proliferation was retained. Unfolded mutants without conformational epitopes did not induce anaphylaxis in peanut-sensitized mice.
CONCLUSIONS
By removing conformational and linear IgE epitopes, a hypoallergenic Ara h 2 mutant with abolished IgE binding and anaphylactogenic potency but retained T-cell activation was generated.
Identifiants
pubmed: 31525384
pii: S0091-6749(19)31183-2
doi: 10.1016/j.jaci.2019.08.036
pmc: PMC7100897
mid: EMS85541
pii:
doi:
Substances chimiques
2S Albumins, Plant
0
Antigens, Plant
0
Ara h 2 allergen, Arachis hypogaea
0
Epitopes
0
Immunoglobulin E
37341-29-0
Types de publication
Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
229-238Subventions
Organisme : Austrian Science Fund FWF
ID : P 30936
Pays : Austria
Organisme : Austrian Science Fund FWF
ID : W 1248
Pays : Austria
Informations de copyright
Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.
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