Single recombinant and purified major allergens and peptides: How they are made and how they change allergy diagnosis and treatment.

OBJECTIVE: To review the current knowledge regarding recombinant and purified allergens and allergen-derived peptides. DATA SOURCES: PubMed, homepages relevant to the topic, and the National Institutes of Health clinical trial database were searched. STUDY SELECTIONS: The literature was screened for studies describing purified and recombinant allergens and allergen-derived peptides. Studies relevant to the topic were included in this review. RESULTS: Advantages and drawbacks of pure and defined recombinant allergens and peptides over allergen extracts in the context of allergy research, diagnosis, and allergen immunotherapy are discussed. We describe how these molecules are manufactured, which products are currently available on the market, and what the regulative issues are. We furthermore provide an overview of clinical studies with vaccines based on recombinant allergens and synthetic peptides. The possibility of prophylactic vaccination based on recombinant fusion proteins consisting of viral carrier proteins and allergen-derived peptides without allergenic activity are also discussed. CONCLUSION: During the last 25 years more than several hundred allergen sequences were determined, which led to a production of recombinant allergens that mimic biochemically and immunologically their natural counterparts. Especially in Europe, recombinant allergens are increasingly replacing allergen extracts in diagnosis of allergy. Despite many challenges, such as high cost of clinical trials and regulative issues, allergy vaccines based on recombinant allergens and peptides are being developed and will likely soon be available on the market.