Lipocalin-type prostaglandin D synthase and egg white cystatin react with IgE antibodies from children with egg allergy.
BACKGROUND
Ovalbumin, ovomucoid, ovotransferrin, lysozyme, and ovomucin are known to be major allergens found in egg white. Egg white protein is composed of over 30 proteins; many of which have neither been identified nor their allergenicities characterized. This study set out to analyze whether unknown proteins that bind to IgE antibodies in serum from patients with egg allergy exist in egg white.


METHODS
Diluted egg white proteins were separated by 2-dimensional (2-D) gel electrophoresis. Immunolabeling was performed on individual patient sera from 19 child patients with egg white allergy and 11 negative control subjects. Spots of egg white proteins that bound to the patients' IgE were identified by mass spectrometry-based proteomics.


RESULTS
Egg white proteins were separated into 63 spots. Twenty-five of the 63 reacted with egg allergy patients' sera, and 10 of the 25 reactive spots showed IgE-reactivity to controls as well. Specific bindings to the IgE from egg allergy patients were found in 15 spots; one of which was confirmed as ovotransferrin. Among the other 14 protein spots, egg white cystatin and lipocalin-type prostaglandin D synthase (L-PGDS) were newly identified proteins that reacted with IgE in patients with egg allergy.


CONCLUSIONS
We demonstrated that L-PGDS and cystatin reacted with serum IgE in patients with egg allergy. Our proteomics-based analysis in egg white gives a comprehensive map of proteins bound with IgE and should assist in enabling more accurate diagnoses and recommendations of desensitizing treatments for individual patients.
Suzuki
Makiko
M
Department of Informative Clinical Medicine, Gifu University Graduate School of Medicine, Gifu, Japan. suzukim@fhw.oka-pu.ac.jp
Fujii
Hidehiko
H
Fujigaki
Hidetsugu
H
Shinoda
Shinji
S
Takahashi
Kanako
K
Saito
Kuniaki
K
Wada
Hisayasu
H
Kimoto
Masumi
M
Kondo
Naomi
N
Seishima
Mitsuru
M
D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D015153:Blotting, Western; D002648:Child; D002675:Child, Preschool; D003001:Cloning, Molecular; D015891:Cystatins / Q000737:chemistry / Q000276:immunology*; D021181:Egg Hypersensitivity / Q000097:blood / Q000276:immunology* / Q000503:physiopathology; D004527:Egg Proteins / Q000737:chemistry / Q000276:immunology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007223:Infant; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D054834:Lipocalins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D040901:Proteomics; D011993:Recombinant Fusion Proteins / Q000235:genetics
D000485:Allergens; D015891:Cystatins; D004527:Egg Proteins; D054834:Lipocalins; D011993:Recombinant Fusion Proteins; D007073:Immunoglobulin E; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase