MOLECULAR-CLONING AND EXPRESSION OF A RECOMBINANT ASPERGILLUS-FUMIGATUS PROTEIN ASP-F-II WITH SIGNIFICANT IMMUNOGLOBULIN-E REACTIVITY IN ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS

The cDNA of Aspergillus fumigatus encoding an allergen was cloned and expressed in Escherichia coli. The 987 bp long cDNA clone expressed a recombinant protein Asp f parallel to of 34 kd. This protein exhibited binding to immunoglobulin E (IgE) in the serum samples from patients with allergic bronchopulmonary aspergillosis (ABPA). The patients with ABPA and central bronchiectasis demonstrated high levels of serum IgE antibodies, whereas patients with ABPA without central bronchiectasis , patients with asthma and Aspergillus skin test reactivity but no evi dence of ABPA, and patients with aspergilloma showed only low levels o f IgE antibody to Asp f II. In two-dimensional electrophoresis, a nati ve antigen electroeluted from an A. fumigatus culture filtrate antigen preparation showed an isoelectric point and molecular weight similar to that of Asp f parallel to. In a competitive enzyme-linked immunosor bent assay (ELISA), the IgE antibody reactivity of Asp fm with patient serum samples could be significantly inhibited by culture filtrate an tigens of A. fumigatus. These results indicate that Asp f II has immun ologic reactivities comparable to those of native A. fumigatus antigen s. The recombinant Asp f parallel to can be expressed in E. coli in la rge quantities and should prove useful as a standardized allergen for sensitive and specific immunodiagnosis of ABPA, especially in patients with central bronchiectasis.