Endogenous function and biological significance of aeroallergens: an update.

Significant advances have been made in delineating the structure and function of the clinically important aeroallergens. Most have now been characterized at the molecular level, and their endogenous function determined. In the period of review, however, several novel allergens have been identified. They include the house dust mite lipophorins and gelsolins, and the birch isoflavone reductase. In addition, the functions of previously described allergens have now been established or inferred on the basis of homology studies. For example, cat Fel d 1 and the grass pollen group 1 allergens possess proteolytic activity and the thaumatin-like plant and pollen allergens possess endo-beta1,3-glucanase activity. Similarly, the lipocalin allergens may possess endonuclease activity, and the mite group 2 allergens may bind cholesterol. The three-dimensional structure of the horse dander lipocalin Equ c 1 and the honey bee Api m 2 allergens have also been determined during the review period. Finally, in this period, a variety of novel or improved immunotherapeutic allergen reagents designed to redirect the host immune response from a T-helper-2 to a T-helper-1 cell phenotype have been described, in particular, allergen and immunostimulatory CpG motif conjugates.