Purification and characterization of a 93 kDa Aspergillus fumigatus antigen with diagnostic potential

A glycoprotein with an apparent molecular weight of 93 kDa was purified from a water-soluble extract of Aspergillus fumigatus NCPF 2109 by single step affinity chromatography using the mannose-specific snowdrop (Galanthus nivalis) lectin coupled to agarose. The carbohydrate moiety contained only mannose and galactose. Partial sequencing of cyanogen bromide fragments of the antigen yielded two sequences, KQNKP and GEIPMKF?PQL, with no homology to any reported proteins. In a preliminary evaluation of its diagnostic potential the 93 kDa antigen was recognized by the sera of four patients with allergic bronchopulmonary aspergillosis, in addition to a monoclonal antibody raised against a partially purified fraction of the A. fumigatus water-soluble extract.