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Isolation and characterization of two complete Ara h 2 isoforms cDNA
Jean-Marc Chatel1, Hervé Bernard, Frank M Orson
1Veterans Affairs Medical Center, Baylor College of Medicine, Houston, Tex., USA. chatel@dsvidf.cea.fr
International Archives of Allergy and Immunology
|May 22, 2003
Summary
Two Ara h 2 isoforms were identified, with Ara h 2.02 potentially being a more potent peanut allergen due to a unique amino acid insertion containing a key IgE binding epitope.
Area of Science:
- Allergen research
- Molecular biology
- Immunology
Background:
- Ara h 2 is a primary peanut allergen, eliciting IgE responses in over 90% of peanut-allergic individuals.
- Previous studies reported partial cDNA and genomic sequences for Ara h 2, which exists as a doublet post-electrophoresis.
Purpose of the Study:
- To elucidate the molecular and genetic characteristics of Ara h 2 isoforms.
- To investigate potential differences in allergenicity between Ara h 2 isoforms.
Main Methods:
- Purification and mass spectrometry analysis of Ara h 2.
- PCR amplification, cloning, and sequencing of Ara h 2 cDNA from a peanut library.
Main Results:
- Mass spectrometry confirmed a molecular doublet for Ara h 2 (16,670 and 18,050 Daltons).
- Sequencing revealed two complete cDNA clones, Ara h 2.01 and Ara h 2.02.
- Ara h 2.02 features a 12-amino acid insertion at position 75, including an additional DPYSPS epitope, compared to Ara h 2.01.
Conclusions:
- Two distinct Ara h 2 isoforms (Ara h 2.01 and Ara h 2.02) were molecularly and genetically characterized.
- The Ara h 2.02 isoform, with its expanded IgE binding epitope, is suggested to be a more potent allergen.