Molecular cloning and immunological characterisation of Cyn d 7, a novel calcium-binding allergen from Bermuda grass pollen.

A cDNA coding for a newly identified Bermuda grass pollen allergen, Cyn d 7, with significant sequence similarity to Ca2+-binding proteins, was isolated from a cDNA expression library using serum IgE from an allergic individual. The deduced amino acid sequence of Cyn d 7 contained two typical Ca2+-binding sites (EF hand domains). Depletion of Ca2+ with EGTA led to a loss of IgE-binding capacity of rCyn d 7. A synthetic peptide based on domain II showed high IgE reactivity. Cyn d 7 therefore represents a grass pollen allergen that belongs to a novel class of Ca2+-binding proteins.