Pru du 1, the Bet v 1-homologue from almond, is a major allergen in patients with birch pollen associated almond allergy

ORIGINAL ARTICLE - Open Access

Stefan Kabasser, Nadja Crvenjak, Stefanie Schmalz, Tanja Kalic, Christine Hafner, Pawel Dubiela, Aleksandra Kucharczyk, Stanislawa Bazan-Socha, Mateusz Lukaszyk, Heimo Breiteneder, Christian Radauer, Merima Bublin

Clin Transl Allergy. 2022 Aug 8;12(8):e12177. doi: 10.1002/clt2.12177.

Abstract

Background

Almond allergy is common and can manifest in two different forms. Primary almond allergy has been reported to be associated with sensitization to almond legumin Pru du 6. In birchendemic regions, there is a link between birch-pollinosis which is likely based on a cross-reactive Bet v 1 homologue, a yet unidentified allergen in almond. Therefore, we sought to identify and characterize a Bet v 1-homologue in almond.

Methods

The expression of a Bet v 1 homologue in almond kernels was confirmed by mass spectrometry.

The recombinant protein was produced in Escherichia coli and its cross-reactivity and allergenic potency was analyzed by IgE quantitative and competitive ELISA, immunoblotting and basophil histamine release using sera from 17 almond allergic patients.

Results

The identified Bet v 1 homologue received the designation Pru du 1.0101. Pru du 1.0101 bound IgE from 82 % of almond allergic patients. Bet v 1 was able to inhibit IgE-binding to rPru du 1 by 100%, while rPru du 1 inhibited IgE binding to rBet v 1 by 48%. Pru du 1.0101 activated basophils, though 100- to 1000-fold higher concentrations were required for maximum activation in comparison to rBet v 1.

Conclusion

Considering the strong inhibition capacity and higher allergenic potency of Bet v 1, the results provide compelling evidence for primary sensitization to Bet v 1 in case of birch pollen associated almond allergy. Combining Pru du 6 and Pru du 1 in diagnostic approaches may help to discriminate between primary and birch-pollen associated almond allergy.

PDF