Evaluation of the Effects of Euglena gracilis on Enhancing Immune Responses in RAW264.7 Cells and a Cyclophosphamide-Induced Mouse Model

Abstract

In this study we evaluated the immune-enhancing effects of β-glucan, the main component of Euglena gracilis ( Euglena ), and Euglena on inflammatory factor expression in RAW264.7 macrophages and ICR mice with cyclophosphamide-induced immunosuppression. Macrophages were treated with β-glucan or Euglena for 48 h. The β-glucan and Euglena groups exhibited higher levels of inducible nitric oxide synthase, nitric oxide, and tumor necrosis factor (TNF)-α than the control (vehicle alone) group. Animals were fed saline and β-glucan (400 mg/kg body weight (B.W.)) or Euglena (400 or 800 mg/kg B.W.) for 19 days, and on days 17–19, cyclophosphamide (CCP, 80 mg/kg B.W.) was administered to induce immunosuppression in the ICR mouse model. CCP reduced the body weight, spleen index, and cytokine expression of the mice. To measure cytokine and receptor expression, splenocytes were treated with concanavalin A (ConA) or lipopolysaccharide (LPS) as a mitogen for 24 h. In vivo, ConA stimulation significantly upregulated the expression of interferon (IFN)-γ, interleukin (IL)-10, IL-12 receptor β1, IL-1β, and IL-2 in splenocytes from the β-glucan- or Euglena -treated groups compared with those in the splenocytes from the CCP-treated group; LPS stimulation increased the levels of the cytokines TNF-α, IL-1β, and IL-6 in splenocytes from the β-glucan- or Euglena -treated groups compared with those from the CCP-treated group, but most of these differences were not significant. These results demonstrate the effect of Euglena in ameliorating macrophages and immunosuppression in CCP-treated mice. Thus, Euglena has the potential to enhance macrophage- and splenocyte-mediated immune-stimulating responses.

Unveiling Immunomodulatory Effects of Euglena gracilis in Immunosuppressed Mice: Transcriptome and Pathway Analysis

“…Euglena and β-glucan have been shown to improve health by enhancing immunity, inhibiting atopic dermatitis, and modulating gut microbial composition [ 6 , 7 ]. In vitro, in vivo, and clinical trial studies have demonstrated that Euglena and β-glucan activate the immune system by releasing cytokines and inducing the immune cells such as natural killer cells or T lymphocytes [ 8 - 10 ]. They also activate the production of TNF-alpha in macrophages and modulate the expression of various cytokines [ 10 ].…”

“…In vitro, in vivo, and clinical trial studies have demonstrated that Euglena and β-glucan activate the immune system by releasing cytokines and inducing the immune cells such as natural killer cells or T lymphocytes [ 8 - 10 ]. They also activate the production of TNF-alpha in macrophages and modulate the expression of various cytokines [ 10 ]. Although they are known for their antitumor, anti-inflammatory, and antiallergic effects, the detailed genetic immune mechanisms involved remain to be elucidated.…”