BACKGROUND: Hazelnuts are a common cause of food allergy. Allergic reactions to hazelnuts range from oral allergy syndrome caused by cross-reactivity between tree pollen and hazelnut proteins to severe anaphylactic reactions. Little information is available regarding the identification of pollen-independent hazelnut allergens. OBJECTIVE: The aim of the study was to identify these pollen-independent allergens in patients with hazelnut allergy with systemic reactions. METHODS: Extracted hazelnut proteins were separated by means of 2-dimensional PAGE, and immunolabeling was performed with individual sera from 14 patients with hazelnut-induced systemic reactions. Edman sequencing was performed on a 40-kd protein identified as an allergen. In parallel, RNA isolated from hazelnuts was used to construct a cDNA library. By using the peptide sequence data, oligonucleotide primers were synthesized and used to screen the library. Full-length cDNA clones were isolated, sequenced, expressed, and screened with patient sera. RESULTS: By using 2-dimensional proteomics, a protein fraction at 40 kd was recognized by serum IgE from 86% (12/14) of the patients with hazelnut allergy with systemic reactions. Two internal amino acid sequences were determined by means of Edman sequencing. Screening of the prepared hazelnut cDNA library with oligonucleotides based on these internal peptide sequences resulted in isolation of a novel protein cDNA. The new protein, named Cor a 9, belongs to the 11S globulin seed storage protein family. This family comprises known food allergens in peanut (Ara h 3) and soybean (glycine max). The pairwise homology among these 3 proteins ranges from 45% to 50%. Interestingly, one known IgE-binding epitope of Ara h 3 shares 67% of homologous amino acid residues with the corresponding area of Cor a 9. The amino acids that differ were previously shown not to be critical for IgE binding in Ara h 3. CONCLUSION: Cor a 9 is the first tree pollen-unrelated hazelnut allergen isolated, sequenced, and cloned. The identification of food allergens is the first step toward generating recombinant allergens for use in future immunotherapeutic approaches. In addition, the detection of conserved IgE epitopes in common food allergens, such as seed storage proteins, might be a useful tool for predicting cross-reactivity to certain foods.
BACKGROUND: Hazelnuts are a common cause of food allergy. Allergic reactions to hazelnuts range from oral allergy syndrome caused by cross-reactivity between tree pollen and hazelnut proteins to severe anaphylactic reactions. Little information is available regarding the identification of pollen-independent hazelnut allergens. OBJECTIVE: The aim of the study was to identify these pollen-independent allergens in patients with hazelnut allergy with systemic reactions. METHODS: Extracted hazelnut proteins were separated by means of 2-dimensional PAGE, and immunolabeling was performed with individual sera from 14 patients with hazelnut-induced systemic reactions. Edman sequencing was performed on a 40-kd protein identified as an allergen. In parallel, RNA isolated from hazelnuts was used to construct a cDNA library. By using the peptide sequence data, oligonucleotide primers were synthesized and used to screen the library. Full-length cDNA clones were isolated, sequenced, expressed, and screened with patient sera. RESULTS: By using 2-dimensional proteomics, a protein fraction at 40 kd was recognized by serum IgE from 86% (12/14) of the patients with hazelnut allergy with systemic reactions. Two internal amino acid sequences were determined by means of Edman sequencing. Screening of the prepared hazelnut cDNA library with oligonucleotides based on these internal peptide sequences resulted in isolation of a novel protein cDNA. The new protein, named Cor a 9, belongs to the 11S globulin seed storage protein family. This family comprises known food allergens in peanut (Ara h 3) and soybean (glycine max). The pairwise homology among these 3 proteins ranges from 45% to 50%. Interestingly, one known IgE-binding epitope of Ara h 3 shares 67% of homologous amino acid residues with the corresponding area of Cor a 9. The amino acids that differ were previously shown not to be critical for IgE binding in Ara h 3. CONCLUSION: Cor a 9 is the first tree pollen-unrelated hazelnut allergen isolated, sequenced, and cloned. The identification of food allergens is the first step toward generating recombinant allergens for use in future immunotherapeutic approaches. In addition, the detection of conserved IgE epitopes in common food allergens, such as seed storage proteins, might be a useful tool for predicting cross-reactivity to certain foods.
Authors: Francisco Goes da Silva; Alberto Iandolino; Fadi Al-Kayal; Marlene C Bohlmann; Mary Ann Cushman; Hyunju Lim; Ali Ergul; Rubi Figueroa; Elif K Kabuloglu; Craig Osborne; Joan Rowe; Elizabeth Tattersall; Anna Leslie; Jane Xu; Jongmin Baek; Grant R Cramer; John C Cushman; Douglas R Cook Journal: Plant Physiol Date: 2005-10 Impact factor: 8.340
Authors: Iris Lauer; Kay Foetisch; Daniel Kolarich; Barbara K Ballmer-Weber; Amedeo Conti; Friedrich Altmann; Stefan Vieths; Stephan Scheurer Journal: Biochem J Date: 2004-10-15 Impact factor: 3.857
Authors: George du Toit; Peter H Sayre; Graham Roberts; Kaitie Lawson; Michelle L Sever; Henry T Bahnson; Helen R Fisher; Mary Feeney; Suzana Radulovic; Monica Basting; Marshall Plaut; Gideon Lack Journal: J Allergy Clin Immunol Date: 2017-10-31 Impact factor: 10.793
Authors: Elena López; Carmen Cuadrado; Carmen Burbano; Maria Aranzazu Jiménez; Julia Rodríguez; Jesús F Crespo Journal: J Clin Bioinforma Date: 2012-05-22