Selective expression of a major allergen and cytotoxin, Asp f I, in Aspergillus fumigatus. Implications for the immunopathogenesis of Aspergillus-related diseases.
Selective expression of a major allergen and cytotoxin, Asp f I, in Aspergillus fumigatus. Implications for the immunopathogenesis of Aspergillus-related diseases.
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DOI：
10.4049/jimmunol.149.10.3354
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发表时间：
1992-11
影响因子：
4.4
通讯作者：
L. Arruda;B. Mann;M. Chapman
中科院分区：
文献类型：
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作者：
L. Arruda;B. Mann;M. Chapman
Asp f I 是一种主要的 18 kDa 烟曲霉过敏原，也是细胞毒素丝裂霉素家族的成员。 Asp f I 基因的核苷酸序列通过对烟曲霉孢子 DNA 扩增的聚合酶链式反应产物进行测序来确定。整个 678 bp DNA 包括位于 N 端丙氨酸密码子之前的 81 bp 前导序列、52 bp 内含子和 444 bp 开放阅读框，编码 149 个氨基酸的蛋白质 (M(r) 16,899)，与来自限制性曲霉的丝裂霉素 99% 同源。基于 mAb 的 ELISA 用于比较孢子、菌丝体和培养滤液中的 Asp f I 水平，并确定过敏原产生的动力学。破坏的菌丝或孢子提取物中的 Asp f I 水平比培养物滤液低 1000 倍，这表明孢子的萌发和真菌的生长对于过敏原的产生至关重要。烟曲霉和限制曲霉中的 Asp f I 水平在第 3 天达到峰值（0.87 至 12.1 微克/ml），然而，在第 3 天或第 8 天，在黄曲霉、黑曲霉、土曲霉和构巢曲霉培养物中未检测到过敏原（< 1.5 ng/ml）。Northern 分析证实 Asp f I mRNA 仅在烟曲霉和限制曲霉中检测到，但在其他四种曲霉属中未检测到。 Asp f I 特异性 DNA 是在对从烟曲霉和限制曲霉获得的基因组菌丝体 DNA 进行聚合酶链式反应扩增后生成的，但不是从其他曲霉属获得的。结果表明Asp f I在烟曲霉中选择性表达，提示该细胞毒素可能是烟曲霉特异的毒力因子。
Asp f I is a major 18-kDa Aspergillus fumigatus allergen and a member of the mitogillin family of cytotoxins. The nucleotide sequence of the Asp f I gene was determined by sequencing polymerase chain reaction products amplified from A. fumigatus spore DNA. The entire 678-bp DNA includes an 81-bp leader sequence, preceding the N-terminal alanine codon, a 52-bp intron, and a 444-bp open reading frame, encoding a 149-amino acid protein (M(r) 16,899), which is 99% homologous to mitogillin from Aspergillus restrictus. A mAb-based ELISA was used to compare Asp f I levels in spores, mycelia, and culture filtrate, and to determine the kinetics of allergen production. Disrupted hyphae or spore extracts had a 1000-fold lower level of Asp f I than culture filtrate, suggesting that germination of spores and growth of the fungus are essential for allergen production. Asp f I levels in A. fumigatus and A. restrictus peaked at day 3 (0.87 to 12.1 micrograms/ml), however, the allergen was not detected in Aspergillus flavus, Aspergillus niger, Aspergillus terreus, and Aspergillus nidulans cultures (< 1.5 ng/ml) on either days 3 or 8. Northern analysis confirmed that Asp f I mRNA was detected only in A. fumigatus and A. restrictus, but not in the other four Aspergillus spp. Asp f I-specific DNA was generated after polymerase chain reaction amplification of genomic mycelial DNA obtained from A. fumigatus and A. restrictus, but not from the other Aspergillus spp. The results show that Asp f I is selectively expressed in A. fumigatus, and suggest that this cytotoxin could be a specific virulence factor for A. fumigatus.