Similar Allergenicity to Different <i>Artemisia</i> Species Is a Consequence of Highly Cross-Reactive Art v 1-Like Molecules

• Main Authors: Isabel Pablos, Matthias Egger, Eva Vejvar, Victoria Reichl, Peter Briza, Danila Zennaro, Chiara Rafaiani, Winfried Pickl, Barbara Bohle, Adriano Mari, Fatima Ferreira, Gabriele Gadermaier
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Medicina
• Subjects: allergens; mugwort pollen; <i>Artemisia</i>; Art v 1; IgE cross-reactivity; defensin-like proteins; polyproline-rich protein; allergy; weeds
• Online Access: https://www.mdpi.com/1010-660X/55/8/504

<i>Background and objectives:</i> Pollens of weeds are relevant elicitors of type I allergies. While many <i>Artemisia</i> species occur worldwide, allergy research so far has only focused on <i>Artemisia vulgaris</i>. We aimed to characterize other prevalent <i>Artemisia</i> species regarding their allergen profiles. <i>Materials and Methods:</i> Aqueous extracts of pollen from seven <i>Artemisia</i> species were characterized by gel electrophoresis and ELISA using sera from mugwort pollen-allergic patients (<i>n</i> = 11). The cDNA sequences of defensin&#8722;proline-linked proteins (DPLPs) were obtained, and purified proteins were tested in a competition ELISA, in rat basophil mediator release assays, and for activation of Jurkat T cells transduced with an Art v 1-specific TCR. IgE cross-reactivity to other allergens was evaluated using ImmunoCAP and ISAC. <i>Results:</i> The protein patterns of <i>Artemisia</i> spp. pollen extracts were similar in gel electrophoresis, with a major band at 24 kDa corresponding to DPLPs, like the previously identified Art v 1. Natural Art v 1 potently inhibited IgE binding to immobilized pollen extracts. Six novel Art v 1 homologs with high sequence identity and equivalent IgE reactivity were identified and termed Art ab 1, Art an 1, Art c 1, Art f 1, Art l 1, and Art t 1. All proteins triggered mediator release and cross-reacted at the T cell level. The <i>Artemisia</i> extracts contained additional IgE cross-reactive molecules from the nonspecific lipid transfer protein, pectate lyase, profilin, and polcalcin family. <i>Conclusions:</i> Our findings demonstrate that DPLPs in various <i>Artemisia</i> species have high allergenic potential. Therefore, related <i>Artemisia</i> species need to be considered to be allergen elicitors, especially due to the consideration of potential geographic expansion due to climatic changes.