Molecular cloning, expression and immunological characterisation of Lol p 5C, a novel allergen isoform of rye grass pollen demonstrating high IgE reactivity

A novel isoform of a major rye grass pollen allergen Lol p 5 was isolated f rom a cDNA expression library. The new isoform, Lol p 5C, shares 95% amino acid sequence identity with Lol p 5A, Both isoforms demonstrated shared ant igenic activity but different allergenic activities. Recombinant Lol p 5C d emonstrated 100% IgE reactivity in 22 rye grass pollen sensitive patients. In comparison, recombinant Lol p 5A showed IgE reactivity in less than 64% of the patients. Therefore, Lol p 5C represents a novel and highly IgE-reac tive isoform allergen of rye grass pollen. (C) 1999 Federation of European Biochemical Societies.