Airborne fungal fragments and allergenicity
Airborne fungal fragments and allergenicity
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DOI：
10.1080/13693780600776308
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发表时间：
2006-09-01
期刊：
影响因子：
2.9
通讯作者：
Schmechel, Detlef
中科院分区：
文献类型：
--
作者：
Green, Brett J.;Tovey, Euan R.;Schmechel, Detlef
人们认为，接触真菌，特别是在受水破坏的室内环境中，会加剧许多不利的健康影响，从疲劳、认知困难或记忆丧失等主观症状到过敏、哮喘和过敏性肺炎等更明确的疾病。由于枚举和识别环境样本中各种真菌成分的方法学困难，了解真菌暴露在这些环境中的作用受到限制。因此，有关个人接触真菌过敏原和致敏性的数据主要基于对一些选定且易于识别的物种的评估。其他空气传播的孢子、菌丝和真菌碎片对暴露和过敏致敏的作用尚不清楚。有报道称，菌丝碎片和孢子计数的结合改善了与哮喘严重程度的关联，人们对雾化真菌碎片的作用越来越感兴趣。这些碎片是源自任何细胞内或细胞外真菌结构的颗粒，并且被分类为亚微米颗粒或较大的真菌碎片。体外研究表明，几种真菌物种的亚微米颗粒的雾化浓度比孢子高得多（300-500 倍），呼吸沉积模型表明，黑穗葡萄穗霉碎片的沉积数量可能是孢子的 230-250 倍。这些模型对人类暴露评估和临床疾病的实际影响尚待阐明。我们开发了创新的免疫检测技术，以确定较大的真菌碎片（包括菌丝和破碎的分生孢子）作为气源性过敏原来源的程度。这些技术基于卤素免疫测定 (HIA)，这是一种免疫染色技术，可使用人血清免疫球蛋白 E (IgE) 检测与 > 1 μm 的单个空气颗粒相关的抗原。我们的研究表明，空气中菌丝总数的浓度通常明显高于单个过敏属的分生孢子。所有菌丝片段中大约 25% 表达可检测的过敏原，并且 IgE 免疫染色的结果定位在菌丝中是异质的。此外，以前未表征的十个属的分生孢子可以被识别为过敏原的来源。这些发现强调了较大的真菌碎片作为气源性过敏原来源的贡献，并提出了真菌暴露的新范例。目前缺乏真菌碎片与建筑相关疾病之间关联的直接证据，为了更好地了解，有必要开发诊断试剂和检测方法，特别是亚微米颗粒的诊断试剂和检测方法。使用单克隆抗体的测定可以测量单个抗原，但解释可能会因真菌物种之间的交叉反应而混淆。最近开发的物种特异性单克隆抗体与荧光共聚焦 HIA 技术结合使用，应该首次能够实现形态上难以辨别的真菌片段的物种形成。这种新方法的应用将有助于表征真菌碎片对真菌造成的不良健康影响的贡献，并提供患者特定的暴露和致敏概况。
Exposure to fungi, particularly in water damaged indoor environments, has been thought to exacerbate a number of adverse health effects, ranging from subjective symptoms such as fatigue, cognitive difficulties or memory loss to more definable diseases such as allergy, asthma and hypersensitivity pneumonitis. Understanding the role of fungal exposure in these environments has been limited by methodological difficulties in enumerating and identifying various fungal components in environmental samples. Consequently, data on personal exposure and sensitization to fungal allergens are mainly based on the assessment of a few select and easily identifiable species. The contribution of other airborne spores, hyphae and fungal fragments to exposure and allergic sensitization are poorly characterized. There is increased interest in the role of aerosolized fungal fragments following reports that the combination of hyphal fragments and spore counts improved the association with asthma severity. These fragments are particles derived from any intracellular or extracellular fungal structure and are categorized as either submicron particles or larger fungal fragments. In vitro studies have shown that submicron particles of several fungal species are aerosolized in much higher concentrations (300-500 times) than spores, and that respiratory deposition models suggest that such fragments of Stachybotrys chartarum may be deposited in 230-250 fold higher numbers than spores. The practical implications of these models are yet to be clarified for human exposure assessments and clinical disease. We have developed innovative immunodetection techniques to determine the extent to which larger fungal fragments, including hyphae and fractured conidia, function as aeroallergen sources. These techniques were based on the Halogen Immunoassay (HIA), an immunostaining technique that detects antigens associated with individual airborne particles > 1 mu m, with human serum immunoglobulin E (IgE). Our studies demonstrated that the numbers of total airborne hyphae were often significantly higher in concentration than conidia of individual allergenic genera. Approximately 25% of all hyphal fragments expressed detectable allergen and the resultant localization of IgE immunostaining was heterogeneous among the hyphae. Furthermore, conidia of ten genera that were previously uncharacterized could be identified as sources of allergens. These findings highlight the contribution of larger fungal fragments as aeroallergen sources and present a new paradigm of fungal exposure. Direct evidence of the associations between fungal fragments and building-related disease is lacking and in order to gain a better understanding, it will be necessary to develop diagnostic reagents and detection methods, particularly for submicron particles. Assays using monoclonal antibodies enable the measurement of individual antigens but interpretation can be confounded by cross-reactivity between fungal species. The recent development of species-specific monoclonal antibodies, used in combination with a fluorescent-confocal HIA technique should, for the first time, enable the speciation of morphologically indiscernible fungal fragments. The application of this novel method will help to characterize the contribution of fungal fragments to adverse health effects due to fungi and provide patient-specific exposure and sensitization profiles.