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 t he human host, as demonstrated by their reactivity with more than 80% of se ra from patients with aspergilloma or allergic bronchopulmonary aspergillos is, We demonstrate here that both antigens are exclusively produced under s ituations of low bioavailability of free Zn2+. Addition of micromolar conce ntrations of Zn2+ to the culture medium strongly stimulated Aspergillus gro wth but totally inhibited ASPND1 or ASPF2 production. This effect was speci fic, since other divalent metals had no effect. Removal of endogenous Zn2by a chelator also stimulated ASPND1 production, and the effect was specifi cally reversed by Zn2+. These results suggest a possible role of these anti gens in the survival of the fungus in the lungs.