Antigens and allergens of Aspergillus fumigatus. II. Their further identification and partial characterization of a major allergen (Ag 3).

These further studies demonstrated that most antigens and allergens detected by allergic bronchopulmonary aspergillosis (ABPA) sera were recognized by rabbit antiserum, and a major allergenic component, Ag 3, as previously demonstrated by self-crossed radioimmunoelectrophoresis, was identified in the conventional system. Affinocrossed immunoelectrophoresis with concanavalin A indicated that for the patients with ABPA, although the major antigens contained alpha-D-manno- or alpha-D-glucopyranoside terminal residues, the major allergenic components did not. Fractionation of the salt-precipitated, protein-enriched fraction by gel filtration on Sephacryl S-200, monitored by fused-rocket immunoelectrophoresis/fused-rocket radioimmunoelectrophoresis with both the ABPA serum pool and specific rabbit antisera, revealed that most of the antigens were in a molecular weight range greater than 43 kd, whereas the allergens spread from as low as 10 to greater than 100 kd. The major allergen, Ag 3, was identified and demonstrated to have a molecular weight of approximately 24 kd. This component does not bind to concanavalin A and is also very heat labile.