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

Authors
Philipp Starkl, Ferdinand Felix, Durga Krishnamurthy, Caroline Stremnitzer, Franziska Roth-Walter, Sara R. Prickett et al.


Lab
Medical University of Vienna, Vienna, Austria / The Alfred Hospital and Monash University, Melbourne, Australia

Journal
Clinical & Experimental Allergy

Abstract
Background
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.

Conclusion 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.

Source :

http://onlinelibrary.wiley.com/doi/10.1111/cea.12031/abstract

Publication request

Thank you for your interest in our product range and your request for this publication, which will be sent to you if the research team and the journal allow it. Our commercial team will contact you as soon as possible.