C-terminal cysteine residues determine the IgE binding of Aspergillus fumigatus allergen Asp f 2. J Immunol 2002 Nov 01;169(9):5137-44
Date
10/23/2002Pubmed ID
12391230DOI
10.4049/jimmunol.169.9.5137Scopus ID
2-s2.0-0036838688 (requires institutional sign-in at Scopus site) 19 CitationsAbstract
The knowledge of the structure function relationship of the allergen is essential to design allergenic variants with reduced IgE binding capacity but intact T cell reactivity. Asp f 2 is a major allergen from the fungus Aspergillus fumigatus and >90% of A. fumigatus-sensitized individuals displayed IgE binding to Asp f 2. In the present study, we evaluated the involvement of C-terminal cysteine residues in IgE binding conformation of Asp f 2. The deletion mutants were constructed by adding three C-terminal cysteines of the native Asp f 2 one at a time to the non-IgE binding Asp f 2 (68-203). The point mutants of Asp f 2 (68-268) with C204A and C257A substitutions were constructed to study the role of C-terminal cysteines in IgE binding. Immunological evaluation of reduced and alkylated Asp f 2 and its mutants were conducted to determine the contribution of free sulfhydryl groups as well as the disulfide bonds in allergen Ab interaction. Four-fold increase in IgE Ab binding of Asp f 2 (68-267) compared with Asp f 2 (68-266) and complete loss in IgE binding of C204A mutant of Asp f 2 (68-268) indicate the involvement of C(204) and C(267) in IgE binding conformation of Asp f 2. A significant reduction in IgE binding of wild and mutated Asp f 2 after reduction and alkylation emphasizes the importance of cysteine disulfide bonds in epitope Ab interaction. The hypoallergenic variants may be explored further to develop safe immunotherapeutic strategy for allergic disorders.
Author List
Banerjee B, Kurup VP, Greenberger PA, Kelly KJ, Fink JNMESH terms used to index this publication - Major topics in bold
AllergensAmino Acid Substitution
Aspergillosis, Allergic Bronchopulmonary
Aspergillus fumigatus
Binding Sites, Antibody
Cysteine
Disulfides
Epitopes
Fungal Proteins
Genetic Vectors
Humans
Immunoglobulin E
Peptide Fragments
Protein Conformation
Recombinant Fusion Proteins
Sequence Deletion
Structure-Activity Relationship
