Fine mapping and structural analysis of immunodominant IgE allergenic epitopes in chicken egg ovalbumin

• Published in: Protein engineering 2003-10, Vol.16 (10), p.747-752
• Main Authors: Mine, Yoshinori, Rupa, Prithy
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Binding Sites, Antibody; Chickens; Child, Preschool; Egg Hypersensitivity - immunology; Epitope Mapping; Female; food allergy/IgE epitope mapping/ovalbumin/peptide synthesis/SPOTs assay; Humans; Hydrophobic and Hydrophilic Interactions; Immunodominant Epitopes - chemistry; Immunodominant Epitopes - immunology; Immunoglobulin E - immunology; Infant; Male; Models, Molecular; Molecular Sequence Data; Ovalbumin - chemistry; Ovalbumin - immunology; Ovum - chemistry; Ovum - immunology; Protein Structure, Tertiary
• ISSN: 0269-2139; 1741-0126; 1460-213X; 1741-0134
• DOI: 10.1093/protein/gzg095

Ovalbumin is a major allergen in hen egg white that causes IgE‐mediated food allergic reactions in children. In this study, the immunodominant IgE‐binding epitopes of ovalbumin were mapped using arrays of overlapping peptides synthesized on activated cellulose membranes. Pooled human sera from 18 patients with egg allergy were used to probe the membrane. Five distinct regions were found to contain dominant allergic IgE epitopes, these being L38T49, D95A102, E191V200, V243E248 and G251N260. The critical amino acids involved in IgE antibody binding were also determined. These epitopes were composed primarily of hydrophobic amino acids, followed by polar and charged residues and being comprised of β‐sheet and β‐turn structures. One epitope, D95A102, consisted of a single α‐helix. These results provide useful information on the functional role of amino acid residues to evaluate the structure–function relationships and structural properties of allergic epitopes in ovalbumin. They also provide a strategic approach for engineering ovalbumin to reduce its allergenicity.