烟曲霉及其渗出物对人中性粒细胞呼吸爆发的影响

目的:探讨烟曲霉及其渗出物(AfD)对肝移植患者和正常人中性粒细胞(PMN)O-2爆发水平的影响,为进一步研究肝移植后患者易感烟曲霉的发生机制奠定基础.方法:用烟曲霉孢子悬液、烟曲霉孢子悬液 烟曲霉渗出物的混合液分别刺激正常人和肝移植后患者的PMN,1.5小时后流式细胞术测定其O-2(超氧阴离子)水平.结果:分离纯化获得的中性粒细胞纯度较高,其比例＞98%,台盼蓝排斥法测活细胞＞98%.相同条件下,孢子悬液、孢子与AfD混合液刺激正常人PMN产生的O-2呼吸爆发水平差异无统计学意义,但二者刺激肝移植患者PMN时,O-2爆发水平有显著差异(P＜0.01)、正常人与患者的PMN所爆发O-2水平有显著差异(P＜0.01).结论:肝移植患者的PMN与混合液所爆发的O-2水平较正常人明显降低,提示这可能与肝移植患者易感烟曲霉菌有一定关系.     

中性粒细胞吞噬功能试验的注意事项及改进方法

中性粒细胞(小吞噬细胞)吞噬功能实验是医学免疫学中的一个必修实验,该实验涉及到很多学科知识的应用。阐述了该实验进行过程中需要注意的事项及改进方法。     

思连康对小鼠腹腔巨噬细胞吞噬率和吞噬指数的影响

目的 研究双歧杆菌四联活菌片（商品名：思连康）对小鼠腹腔巨噬细胞吞噬鸡红细胞吞噬率及吞噬指数的影响。方法 将SPF小鼠30只随机分成三组,每组10只,Ⅰ组灌胃生理盐水,Ⅱ组灌胃婴儿双歧杆菌菌悬液,Ⅲ组灌胃双歧杆菌四联活菌片菌悬液,每天给药0.5 mL,菌液浓度为1.0×108 CFU/mL,连续给药10 d后小鼠腹腔注入2%鸡红细胞悬液1 mL（红细胞数量为2×108个/mL）,30 min后处死,取小鼠腹腔洗液,观察并记录吞噬鸡红细胞的巨噬细胞数及被吞噬的鸡红细胞数,计算吞噬率及吞噬指数。结果 与Ⅰ组相比,Ⅱ组和Ⅲ组小鼠腹腔巨噬细胞吞噬鸡红细胞的吞噬率和吞噬指数均显著升高（Ps＜0.05）,其中Ⅲ组高于Ⅱ组（P＜0.05）。结论 双歧杆菌四联活菌片及其婴儿双歧杆菌通过提高小鼠腹腔巨噬细胞的吞噬率和吞噬指数提高机体的免疫力。     

巨噬细胞吞噬凋亡中性粒细胞及吞噬诱导巨噬细胞死亡的实时动态观察

巨噬细胞有效地吞噬清除凋亡的中性粒细胞,对急性炎症的消退、恢复机体的稳态至关重要.但目前对巨噬细胞吞噬凋亡中性粒细胞的动态过程以及巨噬细胞吞噬凋亡中性粒细胞后的命运转归还知之甚少.本研究动态观察了巨噬细胞吞噬凋亡中性粒细胞的全过程,发现巨噬细胞吞噬凋亡中性粒细胞过程也可分为识别黏附、内吞、消化和残体外排等阶段,同时观察记录了吞噬凋亡中性粒细胞后巨噬细胞被诱导激活死亡的动态过程.通过透射电子显微镜、激光共聚焦扫描显微镜以及特殊染色法显示,吞噬凋亡中性粒细胞诱导巨噬细胞死亡的方式有自噬、凋亡和胀亡等,其中自噬率为(8.00±2.00)%、凋亡率为(12.33±2.08)%、胀亡率为(3.66±1.50)%.这些结果表明,巨噬细胞吞噬凋亡中性粒细胞后自身也经历自噬和凋亡过程,可能是巨噬细胞参与免疫反应的新机制.     

小鼠烟曲霉角膜炎的实验研究

目的 比较伊曲康唑和氟康唑对烟曲霉的体外抗菌活性,观察伊曲康唑对小鼠烟曲霉角膜炎的治疗作用.方法 通过角膜基质注射法建立烟曲霉角膜炎小鼠模型.造模后观察角膜病变,取角膜病变处分泌物做真菌镜检、真菌培养以证实造模成功.用药基法检测伊曲康唑和氟康唑对烟曲霉的最低抑菌浓度( MIC)和最低杀菌浓度(MFC).对烟曲霉角膜炎小鼠给予伊曲康唑治疗,治疗结束行临床评分、炎性评分、菌落形成单位测定以评价疗效.结果 伊曲康唑对烟曲霉的MIC和MFC分别为6.25 μg/mL、12.5 μg/mL;氟康唑对烟曲霉的MIC和MFC分别为500 μg/mL、1 000 μg/mL.伊曲康唑治疗组临床评分、炎性评分和测定的菌落数较对照组均明显减少(P＜0.05).结论 伊曲康唑对烟曲霉的体外抗菌活性优于氟康唑,并且对烟曲霉性角膜炎有明显疗效.     

烟曲霉性角膜炎的实验研究

目的:建立烟曲霉角膜炎小鼠模型,探讨烟曲霉角膜炎的形成条件和致病机制.方法:采用划痕法和角膜基质注射法建立烟曲霉角膜炎小鼠模型.造模后观察角膜病变,对病变角膜组织做真菌检查.结果:划痕法造模小鼠角膜感染率低,病变轻,易自愈;对免疫受损小鼠采用划痕法感染率100%,病情较重,病变持久;基质注射法造模感染率为100%,病变严重、持久.结论:烟曲霉孢子对小鼠角膜的感染率与角膜受损程度及黏附的孢子数量呈正比;宿主免疫受损,易诱发烟曲霉角膜炎且病变较重.     

巨噬细胞的FC受体及其与吞噬功能的关系

本文用EA花环试验及体外吞噬实验检测了小鼠腹腔巨噬细胞(Macrophage,Mφ)的EA 花环率及吞噬功能,结果发现昆明小鼠比同龄C_(57)BL/6、BALB/c及NIH小鼠Mφ的EA花环率高。在昆明及BALB/c小鼠中青年鼠的EA花环率又较老年鼠为高。用黄芪水,黄芪多糖及巯基乙醇酸钠处理后Mφ的EA花环率升高,用秋水仙碱及氢化可的松处理后Mφ的EA花环率降低。MφEA花环率的高低与Mφ吞噬功能的高低相平行。Mφ对抗体包被的CRBC的吞噬能力比对CRBC的吞噬为高,吞噬效应随抗体浓度而改变,表明FC受体介导的吞噬作用大于非特异性吞噬作用。MφFC受体的数目及其功能与Mφ的激活状态及机体的免疫功能状态密切相关。     

烟曲霉细胞壁的组分、组装及其功能概述

环境中普遍存在的腐生丝状真菌烟曲霉Aspergillus fumigatus在免疫功能低下或缺陷的人群中可引起多种急慢性疾病,包括致死率很高的侵袭性曲霉病。细胞壁作为真菌的细胞外骨架结构不仅起维持细胞形状、保护细胞抵抗外界压力等作用,在病原真菌极性生长、入侵新的生态域、启动宿主免疫反应中也起重要作用。细胞壁组分还是真菌感染的分子诊断基础和开发抗真菌药物的理想靶标。近几十年来烟曲霉细胞壁的遗传、生物化学及免疫学方向的研究使其成为研究真菌细胞壁的模式真菌。本文主要概述烟曲霉细胞壁的组分、分子组装机制及其在真菌生存和感染中的作用,并对未来研究方向提出了展望。     

低聚糖奶粉与无低聚糖奶粉对稳定期COPD患者肺功能、营养状态及中性粒细胞氧化和吞噬功能影响的比较

目的：研究低聚糖对稳定期慢性阻塞性肺疾病（COPD）患者肺功能、营养状况及中性粒细胞氧化和吞噬功能的影响。方法：将符合纳入标准的稳定期COPD患者随机分成A组（试验组）（n=35）和B组（对照组）（n=26）。A组在2个月干预期内每日持续服用强化低聚糖中老年奶粉50g/d,B组则每日持续服用等量不含低聚糖的中老年奶粉,收集每组患者试验前后肺功能、血样分析营养指标及中性粒细胞氧化和吞噬功能。结果：2组肺功能及营养指标无显著差异,A组在干预后中性粒细胞氧化功能有明显提高,吞噬功能平均水平也有提高趋势,但未达到统计学意义,B组则无显著差异。结论：功能性低聚糖对肺功能及营养无明显改善,但能较明显地改善COPD患者中性粒细胞功能。     

Chemotherapy of Aspergillus fumigatus keratitis: An experimental study

An experimental Keratitis study of Aspergillus fumigatus was performed in 130 rabbits divided into 12 groups of ten animals each. Three antifungal drugs (myconazole, amphotericin B and pimaricin) were tested using two procedures (topical drops and subconjunctival injections) and two different concentrations (500 and 10 000 times the MIC). In each case, the drugs were applied every 3 h starting 14 h after inoculation. Miconazole was useful at 10 mg/ ml concentration by topical drops and subconjunctival injections, but was less useful at 5 mg/ ml. Amphotericin B was useful at 5 mg/ ml concentration by topical drops and less useful at 2 mg/ ml.No differences were found between the two concentrations by subconjunctival administration. Pimaricin was useful by topical drops at 50 mg/ ml concentration and less useful at 10 mg/ ml as well as by subconjunctival injections.     

Histopathology of experimental Aspergillus fumigatus keratitis

Histopathological studies in rabbit's eyes, 7 and 14 days after intracorneal inoculation with 1×10⁵ Aspergillus fumigatus conidia have been performed.Similar lesions were found in both periods with fungal hyphae in the anterior third of corneal stroma, round cell infiltration from the sclero-corneal edge and in the anterior chamber and, neovascularization.No lesions were found in the Descemet's membrane.Gomori silver-methenamine stain with hematoxiline-eosine counter-stain was found to be the most reliable stain to detect fungal presence in corneal stroma, and Masson's trichromic stain in the study of pathological changes in ocular elements.     

The Volatome of Aspergillus fumigatus

Early detection of invasive aspergillosis is absolutely required for efficient therapy of this fungal infection. The identification of fungal volatiles in patient breath can be an alternative for the detection of Aspergillus fumigatus that still remains problematic. In this work, we investigated the production of volatile organic compounds (VOCs) by A. fumigatus in vitro, and we show that volatile production depends on the nutritional environment. A. fumigatus produces a multiplicity of VOCs, predominantly terpenes and related compounds. The production of sesquiterpenoid compounds was found to be strongly induced by increased iron concentrations and certain drugs, i.e., pravastatin. Terpenes that were always detectable in large amounts were α-pinene, camphene, and limonene, as well as sesquiterpenes, identified as α-bergamotene and β-trans-bergamotene. Other substance classes that were found to be present in the volatome, such as 1-octen-3-ol, 3-octanone, and pyrazines, were found only under specific growth conditions. Drugs that interfere with the terpene biosynthesis pathway influenced the composition of the fungal volatome, and most notably, a block of sesquiterpene biosynthesis by the bisphosphonate alendronate fundamentally changed the VOC composition. Using deletion mutants, we also show that a terpene cyclase and a putative kaurene synthase are essential for the synthesis of volatile terpenes by A. fumigatus. The present analysis of in vitro volatile production by A. fumigatus suggests that VOCs may be used in the diagnosis of infections caused by this fungus.     

The pathobiology of Aspergillus fumigatus

Aspergillus fumigatus is the most prevalent airborne fungal pathogen in developed countries, and in immunocompromised patients causes a usually fatal invasive aspergillosis (IA). Understanding the pathobiology of this fungal species requires not only analysis of the putative fungal virulence factors that stimulate fungal growth and/or survival in the lung environment, but also knowledge of the immune factors containing A. fumigatus in the immunocompetent host that can be debilitated by immunosuppressive therapies, triggering IA. Although the incidence of IA has dramatically increased in recent years, progress in these areas has been limited and, as yet, a single, true virulence factor has not been identified and the mechanisms responsible for protective immunity against A. fumigatus have yet to be elucidated.     

不同形态的烟曲霉对巨噬细胞自噬水平的影响

目的探究烟曲霉静息孢子、膨胀孢子以及菌丝对巨噬细胞自噬水平的影响。方法培养烟曲霉并收获静息孢子,在沙保弱液体培养基中振荡不同时间获得膨胀孢子及菌丝。以3种形态的烟曲霉分组处理RAW264.7细胞,免疫印迹法检测LC3BⅡ蛋白的表达量,逆转录PCR检测自噬相关蛋白Atg5、Atg7、Atg12 mRNA的转录水平。观察不同形态的烟曲霉刺激GFP-LC3B-RAW264.7细胞后GFP-LC3B的表达与定位。结果膨胀的烟曲霉孢子及菌丝刺激巨噬细胞后LC3BⅡ表达水平升高;Atg5与Atg12 mRNA的转录均明显增高,Atg7转录水平无显著变化;膨胀孢子诱导LC3B呈斑点样聚集并与之共定位,烟曲霉菌丝刺激后自噬体增多。结论烟曲霉膨胀孢子与菌丝能显著提高巨噬细胞自噬水平,静息的分生孢子不能引起巨噬细胞自噬功能的应答。     

Gliotoxin from Aspergillus fumigatus affects phagocytosis and the organization of the actin cytoskeleton by distinct signalling pathways in human neutrophils

Gliotoxin is a mycotoxin having a considerable number of immuno-suppressive actions and is produced by several moulds such as Aspergillus fumigatus. In this study, we investigated its toxic effects on human neutrophils at concentrations corresponding to those found in the blood of patients with invasive aspergillosis. Incubation of the cells for 10min with 30-100ng/ml of gliotoxin inhibited phagocytosis of either zymosan or serum-opsonized zymosan without affecting superoxide production or the exocytosis of specific and azurophil granules. Gliotoxin also induced a significant re-organization of the actin cytoskeleton which collapsed around the nucleus leading to cell shrinkage and the disappearance of filopodia. This gliotoxin-induced actin phenotype was reversed by the cAMP antagonist Rp-cAMP and mimicked by pCPT-cAMP indicating that it probably resulted from the deregulation of intracellular cAMP homeostasis as previously described for gliotoxin-induced apoptosis. By contrast, gliotoxin-induced inhibition of phagocytosis was not reversed by Rp-cAMP but by arachidonic acid, another member of a known signalling pathway affected by the toxin. This suggests that gliotoxin can affect circulating neutrophils and favour the dissemination of A. fumigatus by inhibiting phagocytosis and the consequent killing of conidia.     

Contribution to the study of Aspergillus fumigatus Fresenius

50 strains of Aspergillus fumigatus were studied for enzymatic and physiologic profile. Proteolytic and lipolytic activity were lacking. Various ribonucleases and sacchrolytic enzymes were found.     

In vitro infection of human dendritic cells by Aspergillus fumigatus conidia triggers the secretion of chemokines for neutrophil and Th1 lymphocyte recruitment

Given the role played by chemokines in the selective homing of immune cells, we sought to characterize the profile of chemokines produced by human dendritic cells (DC) following in vitro Aspergillus fumigatus infection and their ability to recruit cells involved in the antifungal defense. At the onset of A. fumigatus infection, DC released elevated amounts of CXCL8 that promote the migration of polymorphonuclear cells (PMN). Moreover, soluble factors released from A. fumigatus-infected DC increased also the surface expression of two activation markers, CD11b and CD18, on PMN. A. fumigatus infection resulted also in CCL3, CCL4, CXCL10 and CCL20 productions that induce the migration of effector memory Th1 cells. Moreover, the late expression of CCL19 suggests that A. fumigatus-infected DC could be implicated in the migration of CCR7⁺ naïve T cells and mature DC in lymph nodes. Together these results suggested the involvement of human DC in the regulation of innate and adaptive immunity against A. fumigatus through the recruitment of cells active in the fungal destruction.     

Aspergillus fumigatus: contours of an opportunistic human pathogen

Aspergillus fumigatus is currently the major air‐borne fungal pathogen. It is able to cause several forms of disease in humans of which invasive aspergillosis is the most severe. The high mortality rate of this disease prompts increased efforts to disclose the basic principles of A. fumigatus pathogenicity. According to our current knowledge, A. fumigatus lacks sophisticated virulence traits; it is nevertheless able to establish infection due to its robustness and ability to adapt to a wide range of environmental conditions. This review focuses on two crucial aspects of invasive aspergillosis: (i) properties of A. fumigatus that are relevant during infection and may distinguish it from non‐pathogenic Aspergillus species and (ii) interactions of the pathogen with the innate and adaptive immune systems.     

Spore diffusate isolated from some strains of Aspergillus fumigatus inhibits phagocytosis by murine alveolar macrophages

Aspergillus fumigatus is a ubiquitous fungus that grows in decaying organic matter. It can cause disease in both immunodeficient and immunocompetent patients by using virulence factors to escape the host defenses. Some of these factors, such as a diffusate, released from the spores of A. fumigatus, have previously been described. This diffusate was demonstrated to inhibit oxidative burst and phagocytosis of coated red blood cells. The present study has shown that this substance can inhibit the phagocytosis of A. fumigatus spores by murine alveolar macrophages (MALU) and evaluated the action of this substance. We quantified phagocytosis by MALU cells with and without diffusate and evaluated the inhibition of phagocytosis by testing diffusates from different strains. We conclude that the spore diffusate of some strains of A. fumigatus can reversibly decrease the ability of alveolar macrophages to ingest A. fumigatus spores.