Novel Insight into Neutrophil Immune Responses by Dry Mass Determination of Candida albicans Morphotypes
Novel Insight into Neutrophil Immune Responses by Dry Mass Determination of Candida albicans Morphotypes
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DOI：
10.1371/journal.pone.0077993
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发表时间：
2013-10-30
期刊：
影响因子：
3.7
通讯作者：
Urban, Constantin F.
中科院分区：
文献类型：
--
作者：
Hosseinzadeh, Ava;Urban, Constantin F.
常见的真菌病原体白色念珠菌具有以酵母菌或菌丝的形式生长的能力，并且可以在这些形态之间交替生长。两种形态的总生物量均随生长而增加。然而，只有酵母，而不是菌丝，作为独立的细胞实体存在。感染的多重性（MOI）是一个有用的参数，以确定酵母的初始接种量体外感染试验。由于菌丝的数量难以量化，因此使用MOI无法准确确定酵母和菌丝的可比起始条件。为了避免这个问题，我们建立了一组相关系数，将真菌代谢活性和光密度转换为干质量。利用这些相关性，我们能够准确地比较多形核中性粒细胞在感染相同干质量的酵母和菌丝形态时ROS的产生和IL-8的释放。中性粒细胞反应取决于感染的初始形式，而不考虑白色念珠菌野生型酵母菌在试验期间转化为菌丝生长。大量活的白色念珠菌感染导致中性粒细胞ROS降低，这种降低源于白色念珠菌对ROS的有效解毒，而不直接影响吞噬细胞的ROS机制。此外，我们发现死亡的白色念珠菌诱导的ROS和IL-8的释放明显少于活的真菌，但硫柳汞杀死的白色念珠菌仍然能够解毒中性粒细胞ROS。因此，本研究中提出的干物质方法揭示了中性粒细胞对不同数量和形态的白色念珠菌的反应，并可作为旨在识别多种免疫细胞中形态特异性反应的研究模板。
The common fungal pathogen Candida albicans has the ability to grow as a yeast or as a hypha and can alternate between these morphotypes. The overall biomass of both morphotypes increases with growth. However, only yeasts, but not hyphae, exist as discrete cellular entities. Multiplicity of infection (MOI) is a useful parameter to determine the initial inoculum of yeasts for in vitro infection assays. Since the amount of hyphae is difficult to quantify, comparable starting conditions in such assays cannot be determined accurately for yeasts and hyphae using MOI. To circumvent this problem, we have established a set of correlation coefficients to convert fungal metabolic activity and optical density to dry mass. Using these correlations, we were able to accurately compare ROS production and IL-8 release by polymorphonuclear neutrophils upon infection with equal dry mass amounts of yeast and hyphal morphotypes. Neutrophil responses depended on the initial form of infection, irrespective of C. albicans wild-type yeasts transforming to hyphal growth during the assay. Infection with a high mass of live C. albicans yeasts resulted in lower neutrophil ROS and this decrease stems from efficient ROS detoxification by C. albicans without directly affecting the phagocyte ROS machinery. Moreover, we show that dead C. albicans induces significantly less ROS and IL-8 release than live fungi, but thimerosal-killed C. albicans were still able to detoxify neutrophil ROS. Thus, the dry mass approach presented in this study reveals neutrophil responses to different amounts and morphotypes of C. albicans and serves as a template for studies that aim to identify morphotype-specific responses in a variety of immune cells.