Identification of a new IgE-binding epitope of peanut oleosin that cross-reacts with buckwheat.
Peanut and buckwheat induce a severe allergic reaction, anaphylaxis, which is considered to be mediated by immunoglobulin E (IgE). We identified in this study a new IgE-binding epitope of the peanut allergen that cross-reacted with buckwheat. The phosphate-buffered saline-soluble fraction of buckwheat inhibited the binding between IgE and the peanut allergen. A cross-reactive peptide was isolated from the α-chymotrypsin hydrolysate of peanut. Based on the amino acid sequence and mass spectrometric analysis data, the peptide was identified as Ser-Asp-Gln-Thr-Arg-Thr-Gly-Tyr (SDQTRTGY); this sequence is identical to amino acids 2-9 in the N-terminal hydrophilic domain of oleosin 3 which is located on the surface of the lipid storage body. Synthetic SDQTRTGY was found to bind with IgE in the sera of all eight peanut-allergic patients tested. Since many foods of plant origin contain oleosin, the possibility of an anaphylactic cross-reaction in allergic patients should always be considered.
Research Center for Food Safety, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan. ashoko@mail.ecc.u-tokyo.ac.jp
Shoko
S
Kobayashi
Shinta
S
Katsuyama
Tamae
T
Wagatsuma
Shinji
S
Okada
Soichi
S
Tanabe
D000485:Allergens / Q000737:chemistry* / Q000276:immunology; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry* / Q000276:immunology; D010367:Arachis / Q000737:chemistry* / Q000276:immunology; D001667:Binding, Competitive; D002021:Buffers; D002918:Chymotrypsin / Q000737:chemistry; D003429:Cross Reactions; D019612:Fagopyrum / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000737:chemistry* / Q000276:immunology; D008969:Molecular Sequence Data; D021183:Peanut Hypersensitivity / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry* / Q000276:immunology; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D017386:Sequence Homology, Amino Acid
D000485:Allergens; D052179:Antigens, Plant; D002021:Buffers; D010940:Plant Proteins; D007073:Immunoglobulin E; D002918:Chymotrypsin; C117608:alpha-chymotrypsin