An IFN/STAT1/CYBB axis defines protective plasmacytoid DC-neutrophil crosstalk in Aspergillus fumigatus-infected mice.

Aspergillus fumigatus is the most common cause of invasive aspergillosis (IA), a devastating infection in immunocompromised patients. Plasmacytoid DCs (pDCs) regulate host defense against IA by enhancing neutrophil antifungal properties in the lung. Here, we define the pDC activation trajectory during A. fumigatus infection and the molecular events that underlie the protective pDC-neutrophil crosstalk. Fungus-induced pDC activation began after bone marrow egress and resulted in pDC-dependent regulation of lung type I and type III IFN levels. These pDC-derived products acted on type I and type III IFN receptor-expressing neutrophils and controlled neutrophil fungicidal activity and ROS production via STAT1 signaling in a cell-intrinsic manner. Mechanistically, neutrophil STAT1 signaling regulated transcription and expression of Cybb, which encodes one of 5 NADPH oxidase subunits. Thus, the results indicate that pDCs regulate neutrophil-dependent immunity against inhaled molds by controlling local expression of a subunit required for NADPH oxidase assembly and activity in the lung.