Mapping and mutational analysis of the IgE-binding epitopes on Ara h 1, a legume vicilin protein and a major allergen in peanut hypersensitivity.
Peanut allergy is a significant health problem because of the prevelance and potential severity of the allergic reaction. Serum IgE from patients with documented peanut hypersensitivity reactions and overlapping peptides were used to identify the IgE-binding epitopes on the major peanut allergen, Ara h 1. At least twenty-three different linear IgE-binding epitopes, located throughout the length of the Ara h 1 protein, were identified. All of the epitopes were 6-10 amino acids in length, but there was no obvious sequence motif shared by all peptides. Four of the peptides appeared to be immunodominant IgE-binding epitopes in that they were recognized by serum from more than 80% of the patients tested and bound more IgE than any of the other Ara h 1 epitopes. Mutational analysis of the immunodominant epitopes revealed that single amino acid changes within these peptides had dramatic effects on IgE-binding characteristics. The identification and determination of the IgE-binding capabilities of core amino acids in epitopes on the Ara h 1 protein will make it possible to address the pathophysiologic and immunologic mechanisms regarding peanut hypersensitivity reactions specifically and food hypersensitivity in general.
Burks
A W
AW
Department of Pediatrics, University of Arkansas for Medical Sciences, Arkansas Children's Hospital Research Institute, Little Rock 72205, USA.
Shin
D
D
Cockrell
G
G
Stanley
J S
JS
Helm
R M
RM
Bannon
G A
GA
D000328:Adult; D000485:Allergens / Q000235:genetics / Q000276:immunology*; D000595:Amino Acid Sequence; D052179:Antigens, Plant; D010367:Arachis / Q000276:immunology; D001665:Binding Sites; D002874:Chromosome Mapping; D004252:DNA Mutational Analysis; D018744:DNA, Plant; D018604:Epitope Mapping; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D005512:Food Hypersensitivity / Q000276:immunology; D006023:Glycoproteins; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000276:immunology*; D013329:Structure-Activity Relationship
D000485:Allergens; D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; D018744:DNA, Plant; D018985:Epitopes, B-Lymphocyte; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D007073:Immunoglobulin E