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

Authors

  • P. Starkl,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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  • F. Felix,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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  • D. Krishnamurthy,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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  • C. Stremnitzer,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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  • F. Roth-Walter,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
    2. Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Austria
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  • S. R. Prickett,

    1. Department of Immunology, Monash University, Melbourne, Australia
    2. Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Australia
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  • A. L. Voskamp,

    1. Department of Immunology, Monash University, Melbourne, Australia
    2. Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Australia
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  • A. Willensdorfer,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
    2. Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Austria
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  • K. Szalai,

    1. Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Austria
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  • M. Weichselbaumer,

    1. Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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  • R. E. O'Hehir,

    1. Department of Immunology, Monash University, Melbourne, Australia
    2. Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Australia
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  • E. Jensen-Jarolim

    Corresponding author
    1. Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna, Austria
    • Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
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Correspondence:

Erika Jensen-Jarolim

Messerli Research Institute of the University of Veterinary Medicine Vienna, Medical University of Vienna and University of Vienna

c/o Department of Pathophysiology and Allergy Research

Center of Pathophysiology, Infectiology and Immunology

Medical University of Vienna

Waehringer Guertel 18-20

1090 Vienna

Austria

E-mail: erika.jensen-jarolim@meduniwien.ac.at

Summary

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 IFNγ 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.

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