Characterization of a major antigenic component of Aspergillus fumigatus.

A component of Aspergillus fumigatus, Ag 7, previously identified as a major antigen for patients with allergic bronchopulmonary aspergillosis, has been isolated by gel filtration and further purified by affinity chromatography using monospecific antiserum. The antigen, which binds both specific IgG and IgE antibodies, was shown to be a high molecular weight, 150-200 kD, heat-stable glycoprotein, which binds to concanavalin A, suggesting the presence of alpha-D mannopyrannoside, or alpha-D glucopyrannoside end residues. On sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) it had a subunit of molecular weight 36 kD (with or without prior reduction), which retained antigenicity and allergenicity when tested with patients' sera.