Hybrid Protein Combining Blo t 5 and Der p 2 Allergens from House Dust Mite Shows Allergenic Activity and Diagnostic Potential

Der p 2 and Blo t 5 are main allergens from house dust mites and play central roles in IgE-mediated hypersensitivity. Hybrid allergen molecules represent a promising strategy for component-resolved diagnostics. This study aimed to characterize a recombinant hybrid molecule composed of full-length Der p 2 and Blo t 5 (BP-2) and to evaluate its allergenic activity. Allergenicity and IgE-binding activity of BP-2 were assessed in asthma patients. Immunogenicity was examined in BALB/c mice sensitized and challenged with BP-2, followed by quantification of specific immunoglobulins, histopathological evaluation of airway inflammation and goblet cell hyperplasia, and assessment of airway hyperresponsiveness via methacholine challenge. BP-2 exhibited strong IgE reactivity in asthma patients and effectively discriminated between asthma patients and healthy controls (AUC = 0.806, 95% CI: 0.764–0.844). Cross-inhibition assays demonstrated that BP-2 retains functional epitopes shared with Blo t 5, Der p 2, and allergen extracts. In the murine model, the humoral and cellular immune responses induced by BP-2 suggest a profile with a predominant role of the T2 component characterized by IL-4 and IL-17A production and specific antibody generation. BP-2 is a biologically active hybrid allergen capable of detecting dual sensitization to Dermatophagoides pteronyssinus and Blomia tropicalis, supporting its potential application in component-resolved diagnostics for mite allergy.