Aspergillus fumigatus morphology and dynamic host interactions

Key Points The interaction between Aspergillus fumigatus and the host immune system is highly complex, owing to the capacity of the fungus to adapt to its environment. The different morphological forms of A. fumigatus result in the exposure of different pathogen-associated molecular patterns that trigger distinct sets of pattern recognition receptors, which, in turn, will generate various immune responses that are not always beneficial. Within the host, during infection, environments will change over time, such as the development of a hypoxic environment in the lungs or altered nutritional supply, making it important to realize that additional immunomodulatory treatment has to be tailored for a certain stage of infection. A. fumigatus can adapt and become resistant to antifungal drugs, highlighting the importance of designing novel antifungal drugs and strategies, such as immunotherapy. Aspergillus fumigatus is an environmental fungus that can cause life-threatening disease. In this Review, van de Veerdonk and colleagues describe how A. fumigatus adapts to environmental change, mechanisms of host defence and our current knowledge of the interplay between the host immune response and the fungus. Aspergillus fumigatus is an environmental filamentous fungus that can cause life-threatening disease in immunocompromised individuals. The interactions between A. fumigatus and the host environment are dynamic and complex. The host immune system needs to recognize the distinct morphological forms of A. fumigatus to control fungal growth and prevent tissue invasion, whereas the fungus requires nutrients and needs to adapt to the hostile environment by escaping immune recognition and counteracting host responses. Understanding these highly dynamic interactions is necessary to fully understand the pathogenesis of aspergillosis and to facilitate the design of new therapeutics to overcome the morbidity and mortality caused by A. fumigatus . In this Review, we describe how A. fumigatus adapts to environmental change, the mechanisms of host defence, and our current knowledge of the interplay between the host immune response and the fungus.