In pursuit of the "holy grail": recombinant allergens and peptides as catalysts for the allergen-specific immunotherapy.

This presentation reviews recent progress in knowledge of (i) molecular biology and immunology of allergens and (ii) the methods for the modulation of allergen-specific immune response, with special emphasis on our grass pollen allergens, particularly Pao p IX AL, used as a model. The last few years have seen tremendous progress in molecular characterization of allergens, leading to synthesis of a number of recombinant allergens. Furthermore, studies of the structure-activity relationship of allergens have led to the delineation of the epitopes of these allergens and of widespread cross-reactivities among diverse allergens. In view of the requirement for extensive pre-clinical studies, the application of the recombinant allergens and epitopes in the clinical realm has just begun. Studies in murine systems suggest that these allergens and/or their epitopic peptides downregulate allergen-specific immune responses de novo. The potential and drawbacks of the recombinant allergens and peptides for improving the existing immunotherapeutic approaches and for developing new approaches to specific immunotherapy are discussed.