GM-CSF–mediated epithelial-immune cell cross-talk orchestrates pulmonary immunity to <i>Aspergillus fumigatus</i>
K. Mills, Frederike Westermann, Vanessa Espinosa, Eric Rosiek, Jigar V. Desai, Mariano A. Aufiero, Yahui Guo, Fitty L Liu, Kennedy A. Mitchell, Selma Tuzlak, Donatella De Feo, Michail S. Lionakis, Amariliz Rivera, Burkhard Becher, Tobias M. Hohl
Abstract
Aspergillus fumigatus causes life-threatening mold pneumonia in immunocompromised patients, particularly in those with quantitative or qualitative defects in neutrophils. Whereas innate immune cell cross-talk licenses neutrophil antifungal activity in the lung, the role of epithelial cells in this process is unknown. Here, we find that surfactant protein C (SPC)–expressing lung epithelial cells integrate infection-induced interleukin-1 and type III interferon signaling to produce granulocyte-macrophage colony-stimulating factor (GM-CSF) preferentially at local sites of fungal infection and neutrophil influx. Using in vivo models that distinguish the role of GM-CSF during acute infection from its homeostatic function in alveolar macrophage survival and surfactant catabolism, we demonstrate that epithelial-derived GM-CSF increases the accumulation and fungicidal activity of GM-CSF–responsive neutrophils, which is essential for host survival. Our findings establish SPC + epithelial cells as a central player in regulating the quality and strength of neutrophil-dependent immunity against inhaled mold pathogens.