A comparative analysis of five fungal species isolated from high-altitude air samples based on their induction of murine lung eosinophilia along with heated Asian sand dust

High-altitude aerosols containing fungi and hyphal debris were collected from the Noto Peninsula, Japan, during Asian sand dust (ASD) events. Five fungal species <i>(Bjerkandera adusta</i> (Bje 07B507), <i>Lecythophora</i> (Lec 13H319), <i>Cladosporium cladosporioides</i> (Cla 16H615), <i>Phialocephala sphaeroides</i> (Phi 15H321), and <i>Coniothyrium fuckelii</i> (Con 15H316) were isolated. Fungi were inactivated using 1% formalin combined with heated-ASD (H-ASD) and introduced into the respiratory tracts of BALB/c mice. Con 15H316 exhibited the most significant exacerbation effect. Con 15H316 + H-ASD increased the number of eosinophils and neutrophils in the bronchoalveolar lavage fluid and along with Con 15H316 and Phi 15H321 + H-ASD enhanced the induction of interleukin (IL) −5, IL-13, and eotaxin compared to other mixed samples. Con 15H316 + H-ASD markedly elevated levels of IL-6, monocyte chemotactic protein-3, regulated upon activation, normal T cell expressed and secreted, and lactate dehydrogenase. These changes led to pathological alterations, including mucosal cell proliferation in the airway epithelium and eosinophil infiltration in the submucosa. The ranking of eosinophil infiltration was: Con 15H316+ H-ASD &gt; Phi 15H321 + H-ASD &gt; Cla 16H615 + H-ASD &gt; Lec 13H319 + H-ASD &gt; Bje 07B507+ H-ASD. These results suggest that fungal debris in ASD particles can exacerbate fungal allergies in human lungs.

本研究在亚洲沙尘（Asian sand dust, ASD）事件期间，于日本能登半岛采集了携带有真菌及菌丝碎片的高空气溶胶样本，并从中分离得到5种真菌：烟管菌（Bjerkandera adusta，菌株编号Bje 07B507）、Lecythophora属真菌（菌株编号Lec 13H319）、细枝孢（Cladosporium cladosporioides，菌株编号Cla 16H615）、头状瓶霉（Phialocephala sphaeroides，菌株编号Phi 15H321）以及富克尔盾壳霉（Coniothyrium fuckelii，菌株编号Con 15H316）。采用1%福尔马林结合加热处理的亚洲沙尘（heated-ASD, H-ASD）对分离得到的真菌进行灭活处理，随后将其接种至BALB/c小鼠的呼吸道内。其中菌株Con 15H316展现出最为显著的过敏加重效应。相较于其他混合处理组，Con 15H316+H-ASD组可使小鼠支气管肺泡灌洗液中的嗜酸性粒细胞与中性粒细胞数量显著升高；同时，Con 15H316单独处理组与Phi 15H321+H-ASD组可上调白细胞介素（interleukin, IL）-5、IL-13及嗜酸性粒细胞趋化因子（eotaxin）的表达水平。Con 15H316+H-ASD组还可显著升高IL-6、单核细胞趋化蛋白3（monocyte chemotactic protein-3, MCP-3）、激活诱导正常T细胞表达与分泌因子（regulated upon activation, normal T cell expressed and secreted, RANTES）以及乳酸脱氢酶（lactate dehydrogenase, LDH）的水平。上述变化可引发小鼠肺部病理改变，具体包括气道上皮黏膜细胞增殖及黏膜下层嗜酸性粒细胞浸润。小鼠肺组织嗜酸性粒细胞浸润程度由高到低依次为：Con 15H316+H-ASD组 > Phi 15H321+H-ASD组 > Cla 16H615+H-ASD组 > Lec 13H319+H-ASD组 > Bje 07B507+H-ASD组。本研究结果表明，亚洲沙尘颗粒中的真菌碎片可加重人体肺部的真菌过敏反应。