Work

Identification of the amino‐terminal fragment of Ara h 1 as a major target of the IgE‐binding activity in the basic peanut protein fraction

Year: 2019

Type: article

Abstract: Background Small, basic peanut proteins are often poorly extracted in pH‐neutral buffers that are optimal for the extraction of peanut storage proteins such as Ara h 1. As a result, such proteins are easily missed as potential allergens. Objective To analyse the allergenic composition of the basic peanut protein (BPP) fraction. Methods A peanut extract prepared at pH 4 was fractionated by physicochemical procedures. Chemical analysis was performed by SDS‐PAGE and mass spectrometry. Because immunoblotting was found to be inefficient for most of these small basic proteins, IgE‐binding activity was measured by coupling the fractions to CNBr‐activated Sepharose, followed by incubation with sera from 55 Dutch peanut‐allergic children and 125I‐labelled anti‐IgE. Results Most IgE reactivity of the BPP fraction was due to the 5‐7 kDa amino‐terminal fragment of Ara h 1. This finding was confirmed by the use of the fragment in recombinant form, to which 25/55 of the sera was IgE‐positive. Conclusion The amino‐terminal fragment of Ara h 1, a member of a family of small anti‐microbial proteins, is an allergen independent of the carboxy‐terminal fragment of Ara h 1.

Source: Clinical & Experimental Allergy

DOI: 10.1111/cea.13554