Allergens of Aspergillus fumigatus and Candida boidinii share IgE-binding epitopes.
From an Aspergillus fumigatus complementary deoxyribonucleic acid (cDNA) library displayed on phage surface, an allergen formally termed rAsp f 3 was cloned. The open-reading frame of the cloned gene for the allergen encodes a protein of 168 amino acids with a predicted molecular mass of 18.5 kD, showing 36% identity and 58% similarity to two peroxisomal membrane proteins of Candida boidinii. Recombinant Asp f 3 was expressed as a [His]6-tagged fusion protein in Escherichia coil at yields of 30 mg/L, and was purified by Ni(2+)-chelate chromatography. In an enzyme-linked immunosorbent assay (ELISA), serum IgE antibody reactivity to rAsp f 3 could be detected in 72% of 89 individuals sensitized to A. fumigatus, demonstrating that the protein represents a major allergen of the mold. IgE specific to rAsp f 3 and the two recombinant Candida proteins was further demonstrated by IgE-immunoblot analysis. IgE binding to rAsp f 3 could be inhibited in the ELISA by adding either of the recombinant Candida peroxisomal proteins to sera containing IgE directed against Asp f 3. Taken together, these observations prove that the Asperigillus allergen and the two Candida proteins share IgE-binding epitopes.
Hemmann
S
S
Swiss Institute of Allergy and Asthma Research, Davos Switzerland.
Blaser
K
K
Crameri
R
R
D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D000937:Antigen-Antibody Reactions; D000946:Antigens, Fungal / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D001232:Aspergillus fumigatus / Q000276:immunology*; D001483:Base Sequence; D001666:Binding Sites, Antibody; D002175:Candida / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D005260:Female; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D008875:Middle Aged
D000485:Allergens; D000946:Antigens, Fungal; D000939:Epitopes; D005656:Fungal Proteins; D007073:Immunoglobulin E