Immunoglobulin E-binding and skin test reactivity to hydrophobin XXXX from Cladosporium herbarum, the first allergenic cell wall component of fungi.

@entity1 @entity1522 @entity364 @entity54 @entity56 @entity1576 @entity72335
BACKGROUND: For many years, fungal spores have been recognized as potential causes of @entity1576 . All @entity364 cloned so far represent either secreted or cytoplasmatic proteins, but nothing is known about the involvement of fungal surface proteins in @entity56 . METHODS: A phage surface displayed cDNA-library from the mould Cladosporium herbarum was constructed and phage displaying IgE-binding proteins were selectively enriched with immobilized serum IgE from C. herbarum-sensitized individuals. Inserts encoding putative allergens were sequenced, subcloned and used to produce recombinant proteins. Allergenicity of the proteins was evaluated by IgE binding in Western blots, enzyme-linked immunosorbent assay (ELISA) and skin prick test in a total of 84 @entity1 sensitized to either C. herbarum or @entity54 and three healthy controls. RESULTS: After four rounds of affinity selection, the cDNA-library was enriched for clones displaying IgE-binding molecules. Sequencing of inserts showed that one clone contained an open reading frame predicting a protein of 105 @entity1522 and a calculated molecular weight of 10.5 kDa showing the classical signature of members of the hydrophobin family. The recombinant protein, termed @entity72335 , was able to bind IgE from six @entity1 sensitized to fungi in vitro. Two of those @entity1 were also included in a skin prick test survey and showed strong type I skin reactions to @entity72335 , demonstrating the allergenic nature of C. herbarum hydrophobin and indicating a prevalence of sensitization in the range of 8-9%. In contrast, the hydrophobin HYP1 from @entity54 was not recognized by the sera of the same @entity1 and controls investigated with @entity72335 . CONCLUSION: C. herbarum hydrophobin represents the first component of the cell wall of fungi demonstrated to act as a rare but clinically relevant allergen in vitro and in vivo.
