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Reducing allergenicity by altering allergen fold: a mosaic protein of Phl p 1 for allergy vaccination |
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| Authors: | T Ball B Linhart K Sonneck K Blatt H Herrmann P Valent A Stoecklinger C Lupinek J Thalhamer A A Fedorov S C Almo R Valenta |
| Institution: | Christian Doppler Laboratory for Allergy Research, Division of Immunopathology, Department of Pathophysiology, Center for Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna;;Division of Hematology and Hemostaseology, Department of Internal Medicine I, Vienna General Hospital, AKH, Medical University of Vienna, Vienna;;Christian Doppler Laboratory for Allergy Diagnosis and Therapy, Department of Molecular Biology, University of Salzburg, Salzburg, Austria;;Department of Biochemistry, Albert Einstein College of Medicine, NY, USA |
| Abstract: | Background: The major timothy grass pollen allergen, Phl p 1, resembles the allergenic epitopes of natural group I grass pollen allergens and is recognized by more than 95% of grass-pollen-allergic patients. Our objective was the construction, purification and immunologic characterization of a genetically modified derivative of the major timothy grass pollen allergen, Phl p 1 for immunotherapy of grass pollen allergy. Methods: A mosaic protein was generated by PCR-based re-assembly and expression of four cDNAs coding for Phl p 1 fragments and compared to the Phl p 1 wild-type by circular dichroism analysis, immunoglobulin E (IgE)-binding capacity, basophil activation assays and enzyme-linked immunosorbent assay competition assays. Immune responses to the derivative were studied in BALB/c mice. Results: Grass-pollen-allergic patients exhibited greater than an 85% reduction in IgE reactivity to the mosaic as compared with the Phl p 1 allergen and basophil activation experiments confirmed the reduced allergenic activity of the mosaic. It also induced less Phl p 1-specific IgE antibodies than Phl p 1 upon immunization of mice. However, immunization of mice and rabbits with the mosaic induced IgG antibodies that inhibited patients' IgE-binding to the wild-type allergen and Phl p 1-induced degranulation of basophils. Conclusion: We have developed a strategy based on rational molecular reassembly to convert one of the clinically most relevant allergens into a hypoallergenic derivative for allergy vaccination. |
| Keywords: | allergens immunotherapy pollens |