Allergenic characteristics of a modified peanut allergen.
Attempts to treat peanut allergy using traditional methods of allergen desensitization are accompanied by a high risk of anaphylaxis. The aim of this study was to determine if modifications to the IgE-binding epitopes of a major peanut allergen would result in a safer immunotherapeutic agent for the treatment of peanut-allergic patients. IgE-binding epitopes on the Ara h 2 allergen were modified, and modified Ara h 2 (mAra h 2) protein was produced. Wild-type (wAra h 2) and mAra h 2 proteins were analyzed for their ability to interact with T-cells, their ability to bind IgE, and their ability to release mediators from a passively sensitized RBL-2H3 cell line. Multiple T-cell epitopes were identified on the major peanut allergen, Ara h 2. Ara h 2 amino acid regions 11-35, 86-125, and 121-155 contained the majority of peptides that interact with T-cells from most patients. The wAra h 2 and mAra h 2 proteins stimulated proliferation of T-cells from peanut-allergic patients to similar levels. In contrast, the mAra h 2 protein exhibited greatly reduced IgE-binding capacity compared to the wild-type allergen. In addition, the modified allergen released significantly lower amounts of beta-hexosaminidase, a marker for IgE-mediated RBL-2H3 degranulation, compared to the wild-type allergen.
King
Nina
N
Department of Biochemistry & Molecular Biology, Arkansas Children's Research Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Helm
Ricki
R
Stanley
J Steven
JS
Vieths
Stefan
S
Lüttkopf
Dirk
D
Hatahet
Lina
L
Sampson
Hugh
H
Pons
Laurent
L
Burks
Wesley
W
Bannon
Gary A
GA
D055516:2S Albumins, Plant; D000485:Allergens / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D000818:Animals; D052179:Antigens, Plant; D001665:Binding Sites; D045744:Cell Line, Tumor; D018076:DNA, Complementary; D000939:Epitopes / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D015471:Leukemia, Basophilic, Acute; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D021183:Peanut Hypersensitivity / Q000276:immunology; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D016133:Polymerase Chain Reaction; D051381:Rats; D011994:Recombinant Proteins / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D055516:2S Albumins, Plant; D000485:Allergens; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D018076:DNA, Complementary; D000939:Epitopes; D006023:Glycoproteins; D010940:Plant Proteins; D011994:Recombinant Proteins; D007073:Immunoglobulin E