Title: Purification and characterization of an 18-kd allergen of birch (Betula verrucosa) pollen: identification as a cyclophilin
Authors: Cadot, P ×
Diaz, J F
Proost, Paul
Van Damme, Jozef
Engelborghs, Yves
Stevens, E A
Ceuppens, Jan #
Issue Date: Feb-2000
Series Title: The Journal of allergy and clinical immunology vol:105 issue:2 Pt 1 pages:286-91
Abstract: BACKGROUND: Five birch pollen allergens have been identified so far. In a previous study we detected new birch pollen allergens with an isoelectric point in the range 9.0 to 9.3, present only in extracts prepared at controlled basic pH. OBJECTIVE: The purpose of the current study was to purify and characterize those allergens. METHODS: The target allergens were purified by ion exchange and hydrophobic interaction chromatography. Analyses were carried out by SDS-PAGE, isoelectric focusing, immunoblotting, and amino acid sequencing. The in vivo reactivity of the allergens was evaluated by skin testing. RESULTS: An 18-kd protein, which we named Bet v 7, was purified. This 18-kd protein corresponded to 3 bands on isoelectric-focusing immunoblots that probably represent isoforms. On immunoblots up to 20.8% of birch pollen-allergic patients recognized those allergens. The clinical relevance of Bet v 7 was demonstrated by positive immediate-type skin testing on a patient allergic to birch pollen. Sequencing of an internal peptide yielded an amino acid sequence showing high homology with various plant cyclophilins. The rotamase activity of the protein, inhibited by cyclosporin A, further confirmed that Bet v 7 belongs to the group of cyclophilins. CONCLUSION: We have purified a novel allergen of birch pollen, Bet v 7, belonging to the cyclophilin family. Because cyclophilins are highly conserved proteins over the phylogeny, we may postulate that Bet v 7 is a member of a new family of panallergens.
ISSN: 0091-6749
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Academic Center for General Practice
Laboratory of Molecular Immunology (Rega Institute)
Biochemistry, Molecular and Structural Biology Section
Laboratory of Clinical Immunology
× corresponding author
# (joint) last author

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