Zinc-Regulated Biosynthesis of Immunodominant Antigens from Aspergillus spp.

ASPND1 and ASPF2 are immunodominant antigens from Aspergillus nidulans and A. fumigatus, respectively, that are readily synthesized in infections in the human host, as demonstrated by their reactivity with more than 80% of sera from patients with aspergilloma or allergic bronchopulmonary aspergillosis. We demonstrate here that both antigens are exclusively produced under situations of low bioavailability of free Zn(2+). Addition of micromolar concentrations of Zn(2+) to the culture medium strongly stimulated Aspergillus growth but totally inhibited ASPND1 or ASPF2 production. This effect was specific, since other divalent metals had no effect. Removal of endogenous Zn(2+) by a chelator also stimulated ASPND1 production, and the effect was specifically reversed by Zn(2+). These results suggest a possible role of these antigens in the survival of the fungus in the lungs.