Characterization of the Aspergillus fumigatus chitosanase CsnB and evaluation of its potential use in serological diagnostics
Characterization of the Aspergillus fumigatus chitosanase CsnB and evaluation of its potential use in serological diagnostics
复制标题
DOI：
10.1016/j.ijmm.2014.05.001
复制
发表时间：
2014-07-01
影响因子：
4.1
通讯作者：
Ebel, Frank
中科院分区：
文献类型：
--
作者：
Beck, Julia;Broniszewska, Marzena;Ebel, Frank
烟曲霉是目前主要的空气传播的真菌病原体，因为它的无性孢子分布在空气中。在严重免疫功能低下的患者中，吸入这些分生孢子可导致危及生命的感染。侵袭性铜绿假单胞菌病是一种主要的铜绿假单胞菌相关疾病，其死亡率高，反映了诊断和治疗的时间短。目前的诊断主要依赖于半乳甘露聚糖抗原的血清学检测。检测循环抗体是一种替代方法。在这项研究中，我们已经确定了壳聚糖酶CsnB，一种蛋白质，以前被证明是一个主要的分泌A。为了分析CsnB的生物学功能，我们删除了CsnB基因并产生了CsnB特异性抗体。我们发现A.烟曲霉能够以CsNB依赖性方式在壳聚糖上生长。在壳聚糖上生长期间，在上清液中发现CsnB水平升高，表明壳聚糖引发CsnB产生增强。出乎意料的是，我们发现酒石酸盐也有类似的活性，我们利用重组蛋白分析了侵袭性曲霉病患者的抗体反应。本研究集中于两种抗原：CsnB和作为比较的丝裂霉素，一种分泌的A。烟曲霉核毒素发现对这两种蛋白质的IgG应答，但对CsnB和/或丝裂霉素的抗体水平升高与半乳甘露聚糖抗原测定的结果或真菌感染的特征性临床体征无关。(C)2014爱思唯尔有限公司All rights reserved.
Aspergillus fumigatus is currently the major air-borne fungal pathogen as its asexual spores are distributed through the air. In severely immunocompromised patients, inhalation of these conidia can result in life-threatening infections. Invasive Aspergillosis, a major Aspergillus-associated disease, is associated with a high mortality reflecting short-comings in diagnostics and therapy. Current diagnostics largely rely on the serological detection of the galactomannan antigen. Detection of circulating antibodies is an alternative approach. In this study, we have characterized the chitosanase CsnB, a protein that was previously shown to be a major secreted A. fumigatus antigen and therefore a potential target for antibody-based diagnostics.To analyze the biological function of CsnB we have deleted the csnB gene and generated CsnB-specific antibodies. We found that A. fumigatus is able to grow on chitosan in a CsnB-dependent manner. During growth on chitosan elevated levels of CsnB are found in the supernatants indicating that chitosan triggers enhanced CsnB production. Unexpectedly we have found a similar activity for tartrate.Using recombinant proteins we analyzed antibody responses in patients at risk to develop invasive aspergillosis. We focussed this study on two antigens: CsnB and for comparison mitogillin, a secreted A. fumigatus ribotoxin. IgG responses were found to both proteins, but elevated antibody levels to CsnB and/or mitogillin showed no correlation to the results of the galactomannan antigen assay or clinical signs that are characteristic for fungal infections. (C) 2014 Elsevier GmbH. All rights reserved.