Purpose: The purpose of this work was to determine the pro- and anti-inflammatory properties of the single-cell organism Euglena gracilis (EG) and various fractions of its whole biomass.
Methods: Heterotrophically grown EG was tested, along with its aqueous fraction (E-AQ), the intact linear β-glucan paramylon granules (PAR), and alkaline-solubilized paramylon. Peripheral blood mononuclear cell cultures were treated with the test products and analyzed for a variety of cellular responses. Immune cell activation was evaluated by flow cytometry detection of CD69 levels on CD3−CD56⁺ NK cells, CD3⁺CD56⁺ NKT cells, and monocytes, and cytokines were analyzed from the cell culture supernatants. Antioxidant capacity was measured by Folin–Ciocalteu assay and cellular antioxidant protection and MTT assays.
Results: EG and E-AQ were the most effective in driving immune cell responses as measured by CD69 upregulation on NK and NKT cells and proinflammatory (tumor necrosis factor, IL-6, IL-1β) cytokine production. None of the test products effectively stimulated monocyte. EG and PAR inhibited reactive oxygen species under conditions of oxidative stress. E-AQ contained antioxidants capable of providing cellular antioxidant protection from oxidative damage and protection of mitochondrial function under inflammatory conditions.
Conclusion: The effects of EG on immune function are only partially attributable to the content of the β-glucan, paramylon. The regulation of additional cellular responses, such a reactive oxygen species production and resistance to oxidative stress, is likely mediated by currently unknown molecules found in the EG cell.

Keywords: CAP-e, oxidative stress, PAMP, Dectin-1, paramylon, mannitol


中文翻译：

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Euglena gracilis 的颗粒状和溶解的 β-葡聚糖和非 β-葡聚糖部分可诱导促炎和抗炎的先天免疫细胞反应并表现出抗氧化特性。

目的：这项工作的目的是确定单细胞生物体眼虫(EG) 及其整个生物量的各个部分的促炎和抗炎特性。
方法：对异养生长的 EG 及其水性部分 (E-AQ)、完整的线性 β-葡聚糖副淀粉颗粒 (PAR) 和碱溶性副淀粉进行了测试。用测试产品处理外周血单核细胞培养物并分析各种细胞反应。通过流式细胞术检测 CD3-CD56 ⁺ NK 细胞、CD3 ⁺ CD56 ^{+上的 CD69 水平评估免疫细胞活化}从细胞培养上清液分析NKT细胞、单核细胞和细胞因子。通过 Folin-Ciocalteu 测定和细胞抗氧化保护和 MTT 测定来测量抗氧化能力。
结果：通过 NK 和 NKT 细胞上的 CD69 上调和促炎（肿瘤坏死因子、IL-6、IL-1β）细胞因子产生来衡量，EG 和 E-AQ 在驱动免疫细胞反应方面最有效。没有一种测试产品能有效刺激单核细胞。EG和PAR在氧化应激条件下抑制活性氧。E-AQ 含有抗氧化剂，能够在炎症条件下提供细胞抗氧化保护免受氧化损伤和保护线粒体功能。
结论：EG对免疫功能的影响仅部分归因于β-葡聚糖、副淀粉的含量。其他细胞反应的调节，例如活性氧的产生和对氧化应激的抵抗，可能是由 EG 细胞中目前未知的分子介导的。

关键词： CAP-e, 氧化应激, PAMP, Dectin-1, paramylon, 甘露醇