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Sequence polymorphisms and antibody binding to the group 2 dust mite allergens.
A M Smith1, D C Benjamin, U Derewenda
1Asthma and Allergic Diseases Center, University of Virginia, Charlottesville, VA 22908-1355, USA. ams3k@virginia.edu
International Archives of Allergy and Immunology
|April 18, 2001
Summary
Allergen isoforms like Der p 2 and Der f 2 show significant antibody binding. Minor amino acid substitutions impact binding, but recombinant allergens remain useful for diagnosing allergies.
Area of Science:
- Allergen immunotherapy
- Molecular allergology
- Immunochemistry
Background:
- Group 2 allergens (Der p 2, Der f 2, Eur m 2) are highly similar 14-kD proteins.
- Isoforms within genera exhibit minor amino acid differences (3-4 residues).
Purpose of the Study:
- To investigate the impact of amino acid substitutions on antibody binding in group 2 allergens.
- To assess the diagnostic utility of recombinant allergen isoforms.
Main Methods:
- Recombinant allergen expression and purification from E. coli.
- Enzyme-linked immunosorbent assay (ELISA) and skin testing for antibody binding evaluation.
- Molecular modeling to analyze substitution locations on tertiary structures.
Main Results:
- Most Der f 2 and Der p 2 isoforms bound all tested monoclonal antibodies (mAbs).
- A specific substitution (Asp114Asn) in Der p 2.0101 restored mAb binding and improved IgE binding correlation.
- Recombinant Eur m 2.0101 showed limited mAb binding; IgE binding correlation with Der p 2 was moderate (r²=0.58).
- Lep d 2 did not bind mAbs or allergic sera.
- Molecular modeling indicated substitutions are surface-exposed while preserving the core tertiary fold.
Conclusions:
- Monoclonal antibodies can differentiate between allergen isoforms based on substitutions.
- High IgE binding correlation across isoforms supports their use in allergy diagnosis.
- Recombinant allergens are valuable tools for diagnostic applications.