Implications of the grass group I allergens on the sensitization and provocation process

Grass pollen allergens of group I are particularly important because of their high IgE prevalence and occurrence in all grass species. Four independent IgE-binding regions and one continous epitope were identified. The posttranslational modifications on the molecule increased allergenicity. Phl p 1 is a cysteine protease, as determined by specific substrates, inhibitors and consensus sequence motifs. In analogy to other allergens and/or proteases, we deduce that Phl p 1 might enhance the permeability of the epithelium, influence T helper cells to bias Th2, and increase the IgE production of plasma cells. Thus, the group I allergens seem to be the crucial components in a pollen extract which can mediate sensitization and enhance the triggering of symptoms leading to the persistence of a grass pollen allergy.