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.

侵袭性曲霉病（Invasive aspergillosis）主要发生于免疫功能低下患者，其致病原以烟曲霉（Aspergillus fumigatus）最为常见，而构巢曲霉（Aspergillus nidulans）罕为致病菌。不过，在慢性肉芽肿性疾病（chronic granulomatous disease, CGD）患者中，构巢曲霉却是侵袭性曲霉病的常见致病原，且与更高的死亡率相关。为探究构巢曲霉感染在CGD患者中高发的机制，本研究对比了构巢曲霉与烟曲霉的免疫识别过程。研究采用J774A.1巨噬细胞样细胞与LC3-GFP-mCherry标记的骨髓来源巨噬细胞（bone marrow-derived macrophages, BMDMs）开展活细胞成像实验，结果显示，相较于烟曲霉，机体对构巢曲霉的吞噬作用更为迟缓。该差异可归因于J774A.1细胞的迁移速度较慢，以及骨髓来源巨噬细胞的迁移比例更低。此外，研究还观察到构巢曲霉引发的吞噬体酸化与LC3相关吞噬过程均出现延迟。对人外周血单个核细胞进行细胞因子与氧化爆发检测后发现，构巢曲霉刺激下的氧化爆发水平显著降低。与之相反，构巢曲霉诱导产生的细胞因子浓度则明显升高。综合上述实验结果，本研究证实，相较于烟曲霉，构巢曲霉的吞噬与加工过程更为缓慢，这会导致真菌杀伤效率下降，分生孢子萌发率上升。这种较慢的构巢曲霉清除速率，在特定免疫环境下可能会促进真菌过度增殖。