EFFECTS OF TUNICAMYCIN ON GLYCOPROTEIN ANTIGENS OF ASPERGILLUS-FUMIGATUS

Tunicamycin, which inhibits N-glycosylation of proteins, was used as a tool to determine the type of linkage which occurs in glycoprotein an tigens of Aspergillus fumigatus. When A. fumigatus extracts were elect rophoretically separated and blotted then probed with anti-Aspergillus patients' sera, differences in antigenic profiles were noted when tun icamycin-treated samples were compared with controls. Tunicamycin had no detectable effect on the cellular proteinases of A. fumigatus, most of which are glycosylated. Some enzymatic components were lacking whe n extracellular proteinases were compared with those of control sample s. The major catalase component of A. fumigatus is a concanavalin A (C on A)binding glycoprotein. In cultures grown in the presence of tunica mycin, partially-deglycosylated catalase components were obtained whic h could be distinguished from the native catalase by their altered mob ilities in polyacrylamide gels. The effect of deglycosylation on catal ase antigens was monitored using an antiserum raised to a ConA-binding fraction of A. fumigatus mycelium. These antibodies bound both to the native glycoprotein and the partially deglycosylated material. These latter two were largely unaffected when incubated with an antiserum ra ised to a non-ConA-binding fraction of A. fumigatus which is essential ly carbohydrate free. The ability to produce partially-glycosylated an tigens of A. fumigatus offers a model to study the effect of basic str uctural modifications on both the enzymatic and antigenic activities o f these molecules.