Immunoblot analysis of Aspergillus fumigatus antigen with human antibodies and lectin probes.

Components of culture filtrate antigen of Aspergillus (A.) fumigatus were electrophoretically separated, transferred to hydrophobic durapore membrane, and then probed with patients' sera and lectins. Using human sera from patients with aspergilloma and allergic bronchopulmonary aspergillosis (ABPA), more than 13 IgG binding components were identified. IgG binding to high molecular weight components (HMW) of over 30 kDa was observed in all patient sera tested, but IgG binding to low molecular weight components (LMW) of approximately 18 kDa was observed in 7 out of 8 patients' sera which showed a positive precipitin reaction by means of counterimmunoelectrophoresis. Concanavalin A and lens culinaris agglutinin showed strong binding to HMW but no binding to LMW. Further, strong IgE binding to the 18 kDa component was observed in serum from a patient with ABPA during the acute stage, but not during the convalescence stage. It is suggested that the 18 kDa protein from A. fumigatus is the primary antigen in the serological antibody responses observed in patients with aspergilloma or ABPA.