Supplementary Material for: Differential Kinetics of Aspergillus nidulans and Aspergillus fumigatus Phagocytosis

Invasive aspergillosis mainly occurs in immunocompromised patients and is commonly caused by <i>Aspergillus fumigatus</i>, while <i>A.</i><i>nidulans</i> is rarely the causative agent. However, in chronic granulomatous disease (CGD) patients, <i>A. nidulans</i> is a frequent cause of invasive aspergillosis and is associated with higher mortality. Immune recognition of <i>A. nidulans </i>was compared to <i>A. fumigatus </i>to offer an insight into why <i>A. nidulans</i> infections are prevalent in CGD. Live cell imaging with J774A.1 macrophage-like cells and LC3-GFP-mCherry bone marrow-derived macrophages (BMDMs) revealed that phagocytosis of <i>A. nidulans </i>was slower compared to <i>A. fumigatus</i>. This difference could be attributed to slower migration of J774A.1 cells and a lower percentage of migrating BMDMs. In addition, delayed phagosome acidification and LC3-associated phagocytosis was observed with <i>A. nidulans</i>. Cytokine and oxidative burst measurements in human peripheral blood mononuclear cells revealed a lower oxidative burst upon challenge with <i>A. nidulans</i>. In contrast, <i>A. nidulans</i> induced significantly higher concentrations of cytokines. Collectively, our data demonstrate that <i>A. nidulans </i>is phagocytosed and processed at a slower rate compared to <i>A. fumigatus,</i> resulting in reduced fungal killing and increased germination of conidia. This slower rate of <i>A. nidulans</i> clearance may be permissive for overgrowth within certain immune settings.