Pathogen-specific IgE-reactive cytosolic allergenic epitopes of Aspergillus fumigatus for immunodiagnostic/immunotherapeutic applications against allergic aspergillosis

Aspergillus fumigatus is a significant fungal pathogen responsible for allergic bronchopulmonary aspergillosis (ABPA), a global respiratory disease characterized by high morbidity and mortality. Accurate diagnosis of ABPA remains challenging due to the overlap of clinical and radiological features with other respiratory infections. This study aimed to identify A. fumigatus specific antigens and epitopes to advance immunodiagnostic and immunotherapeutic strategies for ABPA. Clinically confirmed ABPA patients were recruited, and their sera were tested for immunoreactivity against A. fumigatus crude and recombinant allergens. Proteomic analysis was done by employing two-dimensional electrophoresis (2DE) immunoblotting of A. fumigatus cytosolic fractions using sera from 10 individual patients. IgE-reactive spots identified via Q-TOF mass spectrometry revealed 18 allergenic proteins. Among these, two known allergens (Asp-f12 and Asp-f22) and three predicted allergens (sorbitol/xylulose-reductase, Hsp70-chaperone Hsp88, and Hsp70) exhibited cross-reactivity with allergens from other fungi. Notably, 13 allergenic proteins demonstrated significant immunoreactivity specific to ABPA patient sera. In silico epitope analysis identified 9 A. fumigatus specific B-cell and 4 T-cell epitopes with antigenic potential. Molecular docking studies confirmed the binding of representative B-cell and T-cell epitopes to their respective receptors (B-cell receptor and MHC-II complex), demonstrating receptor-specific interactions. These findings highlight pathogen-specific allergens and epitopes that could serve as valuable resources for developing targeted immunodiagnostic and immunotherapeutic tools. This approach may improve the clinical management of ABPA and help reduce its global disease burden.