Identification and Characterization of IgE-reactive Proteins and a New Allergen (Cic a 1.01) from Chickpea (Cicer arietinum)

Scope: Chickpea (Cicer arietinum) allergy has frequently been reported particularly in Spain and India. Nevertheless, chickpea allergens are poorly characterized. We aimed to identify and characterize potential allergens from chickpea.

Methods and results: Candidate proteins were selected by an in silico approach or IgE-testing. Potential allergens were prepared as recombinant or natural proteins and characterized for structural integrity by SDS-PAGE, CD-spectroscopy, and MS analysis. IgE-sensitization pattern of Spanish chickpea allergic and German peanut and birch pollen sensitized patients were investigated using chickpea extracts and purified proteins. Chickpea allergic patients showed individual and heterogeneous IgE-sensitization profiles with extracts from raw and boiled chickpeas. Chickpea proteins PR-10, a late embryogenesis abundant protein (LEA/DC-8), and a vicilin-containing fraction, but not 2S albumin, showed IgE reactivity with sera from chickpea, birch pollen, and peanut sensitized patients. Remarkably, allergenic vicilin, DC-8, and PR-10 were detected in the extract of boiled chickpeas.

Conclusion: Several IgE-reactive chickpea allergens were identified. For the first time a yet not classified DC-8 protein was characterized as minor allergen (Cic a 1). Finally, our data suggest a potential risk for peanut allergic patients by IgE cross-reactivity with homologous chickpea proteins. This article is protected by copyright. All rights reserved.

Keywords: Cic a 1; Cicer arietinum; IgE cross-reactivity; allergen; chickpea allergy.