Trans-Kingdom dsRNA Sensing: Aspergillus fumigatus Mycovirus Activates MDA5/MAVS Immunity and Limits Allergic Bronchopulmonary Aspergillosis

MDA5 is a cytosolic pattern-recognition receptor (PRR) that binds to double-stranded RNA (dsRNA) and subsequently interacts with the signaling adaptor protein MAVS to initiate the antiviral interferon (IFN) response. Our group previously demonstrated that MDA5 is essential for host resistance against the fungal pathogen, Aspergillus fumigatus. Although fungal dsRNA was sufficient to activate MDA5 signaling, the precise source of A. fumigatus dsRNA responsible for this MDA5-stimulating function remains unknown. Here, we demonstrate that the magnitude of the IFN-dependent antifungal response is A. fumigatus strain dependent. Unexpectedly, we found that A. fumigatus isolates infected with dsRNA mycoviruses triggered a more robust MAVS-dependent inflammatory response within alveolar macrophages. Furthermore, dsRNA mycovirus infection increased fungal susceptibility to antifungal killing without altering other A. fumigatus growth characteristics. Although dsRNA mycovirus infection did not alter virulence in an acute bronchopneumonia model of A. fumigatus infection, it significantly impaired virulence and improved disease parameters in a chronic model of allergic bronchopulmonary aspergillosis (ABPA). Collectively, these findings reveal a novel role for trans-kingdom interactions in driving the host antifungal IFN response and modulating virulence in chronic aspergillosis models.