Chokeberry (Aronia melanocarpa) fruit extracts (CE) are rich in polyphenols and usually exhibit immunomodulatory, anti-viral and anti-bacterial effects. We have previously shown that the CE used in this study activated macrophages and stimulated effector T cell differentiation in vitro. When applied orally to healthy mice, CE increased the proportion of CD11c⁺ dendritic cells in the gut-associated lymphoid tissue. CE-pretreated BALB/c mice readily eradicated orally ingested Listeria monocytogenes as evidenced by a slighter decrease in body weight and number of bacteria recovered from the spleen and reduced spleen size compared to the control infected mice. CE pretreatment in infected mice resulted in higher proportions of CD11b⁺ macrophages and CD8⁺ cytotoxic T cells both in the gut and the spleen. Phagocytosis, reactive oxygen species production and the proportions of activated CD86⁺ macrophages (CD11b⁺) and dendritic cells (CD11c⁺) were also enhanced in CE-pretreated infected mice. Furthermore, the expression of inducible nitric oxide synthase and IL-6 was increased in CE-pretreated infected mice and similar results were obtained in peritoneal macrophages in vitro. This effect of CE was associated with increased phosphorylation of IκB and Notch1 production. Finally, CE pretreatment elevated the proportion of perforin-producing cells in the spleen compared to control infected mice. This study demonstrates that prophylactic treatment with CE leads to more rapid eradication of bacterial infection with L. monocytogenes predominantly through increased activity of myeloid cells in the gut and in the spleen.

中文翻译：

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苦莓果实提取物对小鼠李斯特菌感染的免疫调节活性和保护作用。

苦莓（Aronia melanocarpa）水果提取物（CE）富含多酚，通常具有免疫调节，抗病毒和抗菌作用。我们先前已经表明，在这项研究中使用的CE在体外激活巨噬细胞并刺激效应T细胞分化。当口服给健康小鼠时，CE可增加肠道相关淋巴组织中CD11c ⁺树突状细胞的比例。CE预处理的BALB / c小鼠容易根除经口摄入的单核细胞增生性李斯特菌，这是通过与对照感染的小鼠相比，体重和从脾脏中回收的细菌数量略有减少和脾脏大小减小所证明的。感染小鼠的CE预处理导致更高比例的CD11b肠道和脾脏中有⁺巨噬细胞和CD8 ⁺细胞毒性T细胞。在CE预处理的感染小鼠中，吞噬作用，活性氧的产生以及活化的CD86 ⁺巨噬细胞（CD11b ⁺）和树突状细胞（CD11c ⁺）的比例也得到了增强。此外，CE预处理感染的小鼠中诱导型一氧化氮合酶和IL-6的表达增加，并且在体外腹膜巨噬细胞中获得了相似的结果。CE的这种作用与IκB磷酸化和Notch1产生增加有关。最后，与对照感染的小鼠相比，CE预处理可提高脾脏中产生穿孔素的细胞的比例。这项研究表明，CE预防性治疗主要是通过增加肠道和脾脏中髓样细胞的活性，从而更快地根除单核细胞增生李斯特氏菌引起的细菌感染。