Investigation for differences of fungal pathogenecity between environmental strains and passaged strains through mice, using several Trichosporon asahii strains

使用几种 Asahii 毛孢菌菌株研究环境菌株和小鼠传代菌株之间的真菌致病性差异

• 批准号: 13670606
• 负责人: NAGAI Hiroyuki
• 金额: $ 1.86万
• 依托单位: OITA MEDICAL UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670606/
• 关键词: Deep seated mycosis; Trichosporon asahii; PCR (polymerase chain reaction) method; GXM (gluculoxylomannan) antigen; (1→3)-β-D glucan; environmental isolates; clinical isolates; gluculonoxylomannan抗原; (1→3)β-D glucan; Trichosporon ashahii

(1) Trichosporon asahii (T. asahii) is one of a number of opportunistic mycotic pathogens that can cause life-threatening infections in immunocompromised patients. Several investigators have reported that gluculonoxylomannan (GXM) antigens of clinical isolates are higher than that of environmental isolates. Other reports, clinical important fungi such as Candida albicans and Cryptococcus neoformans are known to change their phenotype after repeated subculture or in-vivo passages, and this process is thought to allow some fungi to escape eradication by the host immune system. However there are no studies for morphological changes of Trichosporon asahii after passages in vivo. This study investigated whether in-vivo passages of environmental isolates of Trichosporon asahii in mice changes their phenotype and pathogenicity.(2) The shape of colonies and cell types were clearly different in environmental and clinical isolates. Furthermore, the clinical isolates released significantly higher levels of GXM antigen than environmental isolates. The phenotype of passaged isolates was significantly different from the original environmental isolates with respect to the morphology of colonies and cell type and GXM release. In vivo, toxicity of the environmental isolates was higher than clinical isolates and passaged isolates.(3) These results suggest that the phenotypic changes in T. asahii occur as a result of in-vivo passages. This process may allow a proportion of the fungal population to escape eradication by the host immune system, as GXM antigen is considered to protect the fungi against phagocytosis by polymorphonuclear leucocytes and monocytes in vivo.

(1)Asahii（T. Asahii）是可在免疫功能低下的患者中引起危及生命的感染的许多机会性肌萎缩症病原体之一。一些研究者报道，临床分离株的葡糖醛酸甘露聚糖（GXM）抗原高于环境分离株。其他报道称，已知临床重要真菌如白色念珠菌和新型隐球菌在反复传代或体内传代后会改变其表型，这一过程被认为允许某些真菌逃避宿主免疫系统的根除。但是，目前还没有关于阿萨希丝孢酵母在体内传代后形态学变化的研究。本研究旨在探讨微孢子虫环境分离株在小鼠体内传代是否会改变其表型和致病性。(2)环境分离株和临床分离株的菌落形态和细胞类型明显不同。此外，临床分离株释放的GXM抗原水平显著高于环境分离株。传代分离株的表型与原始环境分离株在菌落形态、细胞类型和GXM释放方面存在显著差异。在体内，环境菌株的毒性高于临床菌株和传代菌株。(3)这些结果表明，T. Asahii是体内传代的结果。这个过程可能会使一部分真菌种群逃脱宿主免疫系统的根除，因为GXM抗原被认为可以保护真菌免受体内多形核白细胞和单核细胞的吞噬作用。

项目成果

Karashima Reiko et al.: "Increased release of glucuronoxylomannan antigen and induced phenotypic changes in Trichosporon asahii by repeated passage in mice."J. Med. Microbiol.. Vol.51. 423-432 (2002)

Karashima Reiko 等人：“通过在小鼠中重复传代，增加了葡萄糖醛酸木甘露聚糖抗原的释放并诱导了 Asahii 毛孢子菌的表型变化。”

Reiko Karashima et al.: "Increased release of glucuronoxylomannan antigen and induced phenotypic changes in Trichosporon asahii by repeated passage in mice"J. Med. Microbiol.. Vol.51. 423-432 (2002)

Reiko Karashima 等人：“通过在小鼠中重复传代，增加葡萄糖醛酸木甘露聚糖抗原的释放并诱导 Asahii 毛孢子菌表型变化”J.

Reiko Karashima et al.: "Increased release of glucuronoxylomannan antigen and induced phenotypic change in Trichosporon asahii by repeated passage in mice"J.Med.Microbiol.. Vol.51. 423-432 (2002)

Reiko Karashima 等人：“通过在小鼠中重复传代，增加葡萄糖醛酸木甘露聚糖抗原的释放并诱导 Asahii 毛孢子菌的表型变化”J.Med.Microbiol.. Vol.51。

Karashima Reiko et al.: "Repeated passages of environmental isolates of Trichosporon. ashahii in mice increase their release of GXM antigen and induce various phenotypic changes"Journal of Medical Microbiology. (in print).

Karashima Reiko 等人：“在小鼠体内反复传代 Trichosporon.ashahii 的环境分离物会增加其 GXM 抗原的释放并诱导各种表型变化”《医学微生物学杂志》。