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

Abstract Aspergillus fumigatus is the causative agent of a global infectious respiratory disease (aspergillosis). Its accurate diagnosis is difficult due to overlapping clinical/radiological features with other respiratory infections. Thus, to identify A. fumigatus-specific entities for more comprehensive use in the immunodiagnosis/immunotherapy of aspergillosis, this work was conducted. We recruited aspergillosis patients after clinical diagnosis; the results included immunoreactivity to A. fumigatus crude/recombinant allergens. Furthermore, 2DE immunoblotting of the A. fumigatus cytosolic fraction was performed with the sera of 10 individual patients, and subsequent Q-TOF analysis of the corresponding IgE-reactive spots from the 2DE-gles identified 18 proteins. These 18 allergenic proteins included 2 known (Asp-f12 and Asp-f22) and 3 predicted allergens (sorbitol/xylulose-reductase, Hsp70-chaperone Hsp88, and Hsp70) of A. fumigatus that exhibited cross-reactivity with other fungal allergens. However, 11 other 13 allergenic proteins from A. fumigatus contained significant immunoreactivity to aspergillosis patient sera. Furthermore, in silico analysis of the antigenic epitopes and cross-reactivity predictions revealed A. fumigatus-specific 9/B-cell and 4/T-cell epitopes. Subsequent docking of representative B-cell and T-cell epitopes with the respective B-cell receptor and MHC-II complex also confirmed receptor-specific binding. These identified pathogen-specific allergens and epitopes could be valuable for future immunodiagnostic and immunotherapeutic applications for better management of aspergillosis and for reducing the disease burden globally.