An unfolded variant of the major peanut allergen Ara h 2 with decreased anaphylactic potential

Philipp Starkl, Ferdinand Felix, Durga Krishnamurthy, Caroline Stremnitzer, Franziska Roth-Walter, Sara Prickett, Astrid Lida Voskamp, Anna Willensdorfer, Krisztina Szalai, Michael Weichselbaumer, Robyn E O'Hehir, Erika Jensen-Jarolim

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25 Citations (Scopus)

Abstract

Peanut allergy causes severe type 1 hypersensitivity reactions and conventional immunotherapy against peanut allergy is associated with a high risk of anaphylaxis. OBJECTIVE: Our current study reports proof of concept experiments on the safety of a stably denatured variant of the major peanut allergen Ara h 2 for immunotherapy. We determined the impact of structure loss of Ara h 2 on its IgE binding and basophil degranulation capacity, T cell reactivity as well as anaphylactic potential. METHODS: The secondary structure of untreated and reduced/alkylated Ara h 2 variants was determined by circular dichroism spectroscopy. We addressed human patient IgE binding to Ara h 2 by ELISA and Western blot experiments. RBL-SX38 cells were used to test the degranulation induced by untreated and reduced/alkylated Ara h 2. We assessed the anaphylactic potential of Ara h 2 variants by challenge of sensitized BALB/c mice. T cell reactivity was investigated using human Ara h 2-specific T cell lines and splenocytes isolated from sensitized mice. RESULTS: Reduction/alkylation of Ara h 2 caused a decrease in IgE binding capacity, basophil degranulation and anaphylactic potential in vivo. However, the human T cell response to reduced/alkylated and untreated Ara h 2 was comparable. Mouse splenocytes showed higher metabolic activity upon stimulation with reduced/alkylated Ara h 2 and released similar IL-4, IL-13 and IFN? levels upon treatment with either Ara h 2 variant. CONCLUSIONS AND CLINICAL RELEVANCE: Reduced/alkylated Ara h 2 might be a safer alternative than native Ara h 2 for immunotherapeutic treatment of peanut allergic patients.
Original languageEnglish
Pages (from-to)1801 - 1812
Number of pages12
JournalClinical & Experimental Allergy
Volume42
Issue number12
DOIs
Publication statusPublished - 2012

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