Glucose/Ribitol Dehydrogenase and 16.9 kDa Class I Heat Shock Protein 1 as Novel Wheat Allergens in Baker's Respiratory Allergy.

Mario Olivieri,Marina Fusi,Jessica Brandi,Daniela Cecconi,Corrado Rizzi,Giovanna Zanoni,Gianluca Spiteri

doi:10.3390/molecules27041212

Abstract

Wheat allergens are responsible for symptoms in 60–70% of bakers with work-related allergy, and knowledge, at the molecular level, of this disorder is progressively accumulating. The aim of the present study is to investigate the panel of wheat IgE positivity in allergic Italian bakers, evaluating a possible contribution of novel wheat allergens included in the water/salt soluble fraction. The water/salt-soluble wheat flour proteins from the Italian wheat cultivar Bolero were separated by using 1-DE and 2-DE gel electrophoresis. IgE-binding proteins were detected using the pooled sera of 26 wheat allergic bakers by immunoblotting and directly recognized in Coomassie stained gel. After a preparative electrophoretic step, two enriched fractions were furtherly separated in 2-DE allowing for detection, by Coomassie, of three different proteins in the range of 21–27 kDa that were recognized by the pooled baker’s IgE. Recovered spots were analyzed by nanoHPLC Chip tandem mass spectrometry (MS/MS). The immunodetected spots in 2D were subjected to mass spectrometry (MS) analysis identifying two new allergenic proteins: a glucose/ribitol dehydrogenase and a 16.9 kDa class I heat shock protein 1. Mass spectrometer testing of flour proteins of the wheat cultivars utilized by allergic bakers improves the identification of until now unknown occupational wheat allergens.

Highlights

Baker’s asthma and rhinitis are frequent occupational diseases with an estimated annual incidence ranging from 1 to 10 cases per 1000 bakery workers and its prevalence does not seem to be declining [1–3]
Wheat proteins can be classified according to their solubility in three fractions: (i) the water/salt-soluble fraction (WSSF) including albumins and globulins, (ii) the water/ethanolsoluble gliadins, and (iii) the glutenins, with the latter soluble in weak acids [7]
In wheat proteins resolved by 2D electrophoresis, more than 100 IgE-binding spots have been detected utilizing the sera of sensitized workers, suggesting high variability in individual sensitization to wheat proteins [8]

Summary

Introduction

Baker’s asthma and rhinitis are frequent occupational diseases with an estimated annual incidence ranging from 1 to 10 cases per 1000 bakery workers and its prevalence does not seem to be declining [1–3]. Any workers exposed to airborne cereal flours inhalation could develop these occupational allergic diseases so 60–70% of bakers with work-related allergic symptoms have increased specific IgE levels to cereal flours [4,5]. The causing agents are proteins mainly present in wheat flour; additives and enzymes contained in multigrains might be involved [6]. Wheat proteins can be classified according to their solubility in three fractions: (i) the water/salt-soluble fraction (WSSF) including albumins and globulins, (ii) the water/ethanolsoluble gliadins, and (iii) the glutenins, with the latter soluble in weak acids [7]. The highest percentage of IgE binding was observed in the WSSF containing several allergens identified by proteomic approach even if all the three wheat flour fractions contain

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