POLLEN ALLERGENS - DEVELOPMENT AND FUNCTION

Pollen allergens interact with the human immune system and the resulti ng IgE antibodies provide specific probes for their identification and characterisation. In one case, grass allergenic proteins are expresse d late in pollen development coincident with the laying down of reserv es. Sequence similarity of allergens has indicated possible functions for some allergens. The major birch pollen allergen shows sequence sim ilarity with pathogenesis-related proteins, which form a secondary res ponse in plant host-pathogen interactions and show anti-microbial acti vity. Some allergens of unknown function are cysteine-rich proteins, w hile some others have cysteine-rich regions; for example, the major al lergen from rye-grass pollen, Lol p 1, has a cysteine-rich N-terminal region, while at the C-terminal region four tryptophan residues togeth er with tyrosine and phenylalanine residues resemble those of cellulos e- or sugar-binding domains of other proteins. Several pollen allergen s show sequence similarity to cell wall-associated enzymes, while othe rs show hydrolytic enzyme activity often associated with cell walls.