Type III interferons trigger antiviral responses and transcriptionally overlap type I interferons but differ mainly in their compartmentalized effects on mucosal epithelia. In Science Immunology, Rivera and colleagues demonstrate an essential role for type III interferons in the control of Aspergillus fumigatus, a pathogenic fungus. Infection with A. fumigatus triggers rapid release of type I interferons, chiefly from pulmonary CCR2+ monocytes. The type I interferons thus generated drive the production of type III interferons from both hematopoietic sources and non-hematopoietic sources. Type III interferons then act directly on neutrophils to activate their antifungal responses. The classic role of type III interferons on the epithelium does not seem to be essential for this response. These findings demonstrate an unexpected target cell and role for type III interferons and furthermore suggest new options for the treatment of fungal infection.

Sci. Immunol. (6 October 2017) 10.1126/sciimmunol.aan5357