14 Comprehensive Expression of Recombinant House Dust Mite Allergens for Component-Resolved Diagnosis

BACKGROUND: Allergen-specific immunotherapy (SIT) is the only promising treatment of allergy. However, current SIT has limitations such as a need for long-term medication and a risk of systemic anaphylaxis. Those issues are raised mainly because current SIT procedure is carried out using crude allergen extract, which may also induce a harmful neo-sensitization. Use of defined recombinant allergens would be a preferable alternative for the next generation SIT vaccine as well as for the development of component-resolved diagnosis (CRD), which enables to prescribe a patient-tailored vaccine. Objective of this study is to construct a production system of recombinant house dust mite (Dermatophagoides farinae) allergens, and to test their usefulness for molecular diagnosis. METHODS: Thus far, the WHO/IUIS allergen nomenclature subcommittee has approved 24 Dermatophagoides allergens. Among them, we sought to express 20 groups of D. farinae allergens (Der f 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 20, 21, and 22) using the Escherichia coli cold shock expression system. We also tried to express additional new antigens [Mag133 (a highly-conserved UK114/YER057c/YjgF family member), DFA22 (a new group 2 family member), and DFA67 (peroxiredoxin)] that we originally identified as major allergens with high IgE-binding frequencies. IgE-binding ability of those recombinant allergens was assessed by western blot analysis. We also tested whether these allergens were applicable for the development of CRD. RESULTS: We confirmed successful expression of above D. farinae allergen molecules as soluble recombinant proteins. Western blot analysis revealed that these recombinant allergens retained IgE-binding capacity. We also found that house dust mite-allergic patients showed differential IgE-binding signatures against them, suggesting that our recombinant allergens are useful to determine sensitized allergen molecules in individual patients. CONCLUSIONS: Here we carried out the comprehensive expression of recombinant D. farinae major allergens. The recombinant allergen repertoire offers an essential platform for the future molecular diagnostics of dust mite allergy.