Maize food allergy: lipid-transfer proteins, endochitinases, and alpha-zein precursor are relevant maize allergens in double-blind placebo-controlled maize-challenge-positive patients.
Italian patients with maize anaphylaxis have been shown to have IgE toward two major maize allergens: an alpha-amylase inhibitor and a 9-kDa LTP. A complete study on maize food allergens in patients with positive maize double-blind, placebo-controlled food challenge (DBPCFC) is lacking. The objective was to utilize the three maize protein fractions to identify and characterize the most relevant IgE-binding proteins recognized by the sera of Italian and Swiss patients with either a positive maize-DBPCFC or a history of maize-induced anaphylaxis. Osborne's protein fractions of maize were extracted to obtain water-soluble, total zein, and total protein fractions. Protein IgE-binding capacity was investigated by SDS-PAGE immunoblotting using the sera from DBPCFC-positive patients and from patients with maize-induced anaphylaxis. Purified maize LTP was used to inhibit the IgE immunoblotting of the three protein fractions. IgE immunoblotting demonstrated that the 9-kDa LTP was recognized by all the Italian patients and by none of the Swiss patients. Other allergens were: 14-kDa alpha-amylase inhibitor, 30-kDa endochitinases A and -B, 19 kDa zein-beta precursor, and 26 kDa zein-alpha precursor; a newly described allergen, the globulin-2 precursor, identified in the total protein fraction. It is noteworthy that maize LTP and endochitinase were cross-reactive with grape LTP and one grape endochitinase. LTP was found to be the only major allergen in Italian patients with either positive maize challenge or a history of maize-induced anaphylaxis. We have identified other maize allergens in subjects with maize food allergy, as grape cross-reactive endochitinase, however, the clinical significance of these proteins needs to be investigated in larger groups of patients with allergy to these food items.
Pastorello
Elide A
EA
Unit of Allergology and Immunology-Niguarda Ca' Granda Hospital, Piazza Ospedale Maggiore 3, 20162 Milan, Italy. allergologia@ospedaleniguarda.it
Farioli
Laura
L
Pravettoni
Valerio
V
Scibilia
Joseph
J
Conti
Amedeo
A
Fortunato
Donatella
D
Borgonovo
Linda
L
Bonomi
Simona
S
Primavesi
Laura
L
Ballmer-Weber
Barbara
B
D000328:Adult; D000368:Aged; D000707:Anaphylaxis / Q000209:etiology; D052179:Antigens, Plant; D002352:Carrier Proteins / Q000276:immunology*; D002648:Child; D002688:Chitinases / Q000276:immunology*; D004311:Double-Blind Method; D005260:Female; D005512:Food Hypersensitivity / Q000209:etiology* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D007558:Italy; D008297:Male; D008875:Middle Aged; D010919:Placebos; D010940:Plant Proteins; D011485:Protein Binding; D012698:Serologic Tests / Q000379:methods*; D055815:Young Adult; D003313:Zea mays / Q000276:immunology*; D015028:Zein / Q000276:immunology*
D052179:Antigens, Plant; D002352:Carrier Proteins; D010919:Placebos; D010940:Plant Proteins; C030363:lipid transfer protein; D007073:Immunoglobulin E; D015028:Zein; D002688:Chitinases