烟曲霉硫氧还蛋白还原酶对侵袭性曲霉病小鼠的免疫保护作用

Protective effect of thioredoxin reductase GliT of Aspergillus fumigatus in a murine model of invasive aspergillosis

目的探讨烟曲霉硫氧还蛋白还原酶(thioredoxin reductase,TR)对侵袭性曲霉病(invasive aspergillosis,IA)的免疫保护作用。方法 C57BL/6小鼠随机分为免疫组和对照组,免疫组小鼠用重组TR免疫2次。感染烟曲霉前用环磷酰胺和地塞米松对全部小鼠进行免疫抑制处理,通过气道穿刺法向气管内注入烟曲霉孢子悬液,建立IA疾病模型。观察两组小鼠的存活率、局部器官真菌载量、肺组织病理变化、肺泡灌洗液细胞分类计数,评估TR蛋白的免疫保护作用。结果存活率:免疫组小鼠7d存活率为64.7%,对照组为0。肺组织匀浆烟曲霉CFU中位数:存活小鼠为0,死亡小鼠为44(P25,P75为21,70)(P<0.01)。组织病理学检观察:死亡小鼠肺肿胀出血、肺泡间隔增宽、大量炎症细胞聚集、组织灶状坏死,并有大量烟曲霉菌丝存在,而存活小鼠肺组织损伤程度轻,且组织间无菌丝。肺泡灌洗液涂片染色细胞计数显示:存活小鼠单个核细胞约占84.2%,中性粒细胞仅占15.8%;死亡小鼠单个核细胞占33.6%,中性粒细胞约占66.4%。结论烟曲霉重组蛋白TR能诱导小鼠产生抵抗IA的免疫保护力,是一个有潜力的保护性抗原。

Objective To investigate the immunoprotection in mice immunized with thioredoxin reductase GliT of Aspergillus fumigatus.Methods C57BL/6mice were randomly assigned into two groups：immunization group intramuscularly immunized with recombinant TR for two times;control group intramuscularly immunized with PBS instead of TR.Survival rate,A.fumigatus lung burdens,pathologic examination and cell count of alveolar lavage were evaluated.Results The survival rate of immunization group was 64.7% within 7days after infection while that of control group was 0.The medians of CFUs from the lung tissues of the suvivors and the nonsuvivors were 0and 44（P25,P75 were 21,70）respectively（P0.01）.Pulmonary pathology indicated that the lungs of the dead immunized mice and control mice showed alveolar hemorrhage,inflammatory cells recruitment,focal tissue necrosis and hyphal elements throughout the entire lung.In contrast,the lung tissues of the survivors were damaged slightly and free of hyphal elements.Alveolar lavage fluid smear showed that the counting of the survival is given priority to with mononuclear cells,accounting for about 84.2%,neutrophils accounted 15.8%.The counting of the nonsurvival is given priority to with neutrophils,accounting for about 66.4%,while 33.6% mononuclear cells.Conclusion Recombinant TR of Aspergillus fumigatus can induce a modest protection in a murine model of invasive aspergillosis and might be a potential protective antigen.