A polysaccharide fraction from Achillea millefolium increases cytokine secretion and reduces activation of Akt, ERK and NF-κB in THP-1 monocytes.

Achillea millefolium has been used in traditional medicine for a number of ailments, including skin inflammation and wounds. A polysaccharide fraction (Am-25-d) isolated from aqueous extract from A. millefolium had an average molecular weight of 270 kDa and a monosaccharide composition of GalA, Gal, Ara, Xyl, Rha in molar ratio of 28:26:23:9:7. THP-1 cells primed with IFN-γ and stimulated with LPS in the presence of Am-25-d secreted more IL-1ß, IL-8, IL-10, IL-12p40, IL-23 and TNF-α than THP-1 cells stimulated in the absence of Am-25-d. However, when added to unstimulated cells Am-25-d did not increase secretion of the cytokines examined. Stimulating THP-1 monocytes in the presence of Am-25-d led to decreased nuclear concentrations of NF-κB and phosphorylation of ERK1/2 and Akt kinases compared with that when the cells were stimulated without Am-25-d. These findings indicate that Am-25-d isolated from A. millefolium has immunoenhancing properties that may be mediated via the Akt pathway.

A heteroglycan from the cyanobacterium Nostoc commune modulates LPS-induced inflammatory cytokine secretion by THP-1 monocytes through phosphorylation of ERK1/2 and Akt.

Cyanobacteria (blue-green algae) have been consumed as food and used in folk medicine since ancient times to alleviate a variety of diseases. Cyanobacteria of the genus Nostoc have been shown to produce complex exopolysaccharides with antioxidant and antiviral activity. Furthermore, Nostoc sp. are common in cyanolichen symbiosis and lichen polysaccharides are known to have immunomodulating effects. Nc-5-s is a heteroglycan isolated from free-living colonies of Nostoc commune and its structure has been characterized in detail. The aim of this study was to determine the effects of Nc-5-s on the inflammatory response of lipopolysaccharide (LPS)-stimulated human THP-1 monocytes and how the effects are mediated. THP-1 monocytes primed with interferon-γ and stimulated with LPS in the presence of Nc-5-s secreted less of the pro-inflammatory cytokine interleukin (IL)-6 and more of the anti-inflammatory cytokine IL-10 than THP-1 monocytes stimulated without Nc-5-s. In contrast, Nc-5-s increased LPS-induced secretion of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α and IL-8. Nc-5-s decreased LPS-induced phosphorylation of the extracellular regulated kinase (ERK)1/2 and Akt kinase, but did not affect phosphorylation of the p38 kinase, activation of the nuclear factor kappa B pathway, nor DNA binding of c-fos. These results show that Nc-5-s has anti-inflammatory effects on IL-6 and IL-10 secretion by THP-1 monocytes, but its effects are pro-inflammatory when it comes to TNF-α and IL-8. Furthermore, they show that the effects of Nc-5-s may be mediated through the ERK1/2 pathway and/or the Akt/phosphoinositide 3-kinase pathway and their downstream effectors. The ability of Nc-5-s to decrease IL-6 secretion, increase IL-10 secretion and moderate ERK1/2 activation indicates a potential for its development as an anti-inflammatory agent.

Dietary omega-3 fatty acids enhance the B1 but not the B2 cell immune response in mice with antigen-induced peritonitis.

The effects of omega-3 fatty acids on the adaptive immune response have mainly been analysed in vitro with varying results. How omega-3 fatty acids affect the adaptive immune response in vivo is largely unknown. This study examined the effects of dietary fish oil on the adaptive immune response in antigen-induced inflammation in mice, focusing on its effects on B cells and B cell subsets. Mice were fed a control diet with or without 2.8% fish oil, immunized twice with methylated BSA (mBSA) and peritonitis induced by intraperitoneal injection of mBSA. Serum, spleen and peritoneal exudate were collected prior to and at different time points after induction of peritonitis. Serum levels of mBSA-specific antibodies were determined by ELISA and the number of peritoneal and splenic lymphocytes by flow cytometry. The levels of germinal center B cells and IgM(+), IgG(+) and CD138(+) cells in spleen were evaluated by immunoenzyme staining. Mice fed the fish oil diet had more peritoneal B1 cells, more IgM(+) cells in spleen and higher levels of serum mBSA-specific IgM antibodies compared with that in mice fed the control diet. However, dietary fish oil did not affect the number of peritoneal B2 cells, splenic IgG(+) or CD138(+) cells or serum levels of mBSA-specific IgG antibodies in mice with mBSA-induced peritonitis. These results indicate that dietary fish oil can enhance the adaptive immune response, specifically the B1 cell response, which may lead to better protection against secondary infection as well as improvement in reaching homeostasis following antigenic challenge.

Dietary fish oil reduces the acute inflammatory response and enhances resolution of antigen-induced peritonitis.

Dietary n-3 polyunsaturated fatty acids (PUFA) influence the inductive phase of inflammation but less is known about their effects on the resolution phase. This study examined the effects of dietary fish oil on induction and resolution of antigen-induced inflammation in mice. Mice were fed a control diet with or without 2.8% fish oil, immunized twice with methylated BSA (mBSA) and inflammation induced by intraperitoneal injection of mBSA. Prior to and at different time points after mBSA administration, peritoneal cells were analyzed and expression of surface molecules determined by flow cytometry. Concentration of chemokines, cytokines and soluble cytokine receptors was determined by ELISA. Mice fed the fish oil diet had fewer peritoneal neutrophils, shorter resolution interval and lower levels of pro-inflammatory cytokines and chemokines than mice fed the control diet. In mice fed the fish oil diet there was an early peak in peritoneal levels of the immunosuppressive molecules sIL-6R and TGF-ß, that was not seen in mice fed the control diet. In the resolution phase, peritoneal macrophages from mice fed the fish oil diet expressed more of the atypical chemokine receptor D6 and peritoneal TGF-ß levels were higher than that in mice fed the control diet. Furthermore, in the late-resolution phase there were more peritoneal eosinophils and macrophages in mice fed the fish oil diet than in mice fed the control diet. These results demonstrate a suppressive effect of n-3 PUFA on the inductive phase of inflammation and indicate an enhancing effect of n-3 PUFA on resolution of inflammation.

Aqueous extracts from Menyanthes trifoliate and Achillea millefolium affect maturation of human dendritic cells and their activation of allogeneic CD4+ T cells in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: Menyanthes trifoliate and Achillea millefolium have been used in traditional medicine to ameliorate chronic inflammatory conditions. The aim of this study was to identify the effects of ethanol and aqueous extracts of Menyanthes trifoliate and Achillea millefolium on maturation of dendritic cells (DCs) and their ability to activate allogeneic CD4(+) T cells. MATERIALS AND METHODS: Human monocyte-derived DCs were matured in the absence or presence of lyophilised aqoueous or ethanol extracts from Menyanthes trifoliate or Achillea millefolium and their expression of surface molecules analysed with flow cytometry and cytokine secretion measured by ELISA. DCs matured in the presence of aqueous extracts from Menyanthes trifoliate and Achillea millefolium were co-cultured with allogeneic CD4(+) T cells and the expression of surface molecules by T cells and their cytokine secretion and cell proliferation determined. RESULTS: Maturation of DCs in the presence of aqueous extracts from Menyanthes trifoliate or Achillea millefolium did not affect expression of the surface molecules examined but reduced the ratio of secreted IL-12p40/IL-10, compared with that by DCs matured in the absence of extracts. Allogeneic CD4(+) T cells co-cultured with DCs matured in the presence of aqueous extract from Menyanthes trifoliate secreted less IFN-γ, IL-10 and IL-17 than CD4(+) T cells co-cultured with DCs matured without an extract. Maturation of DCs in the presence of aqueous extract from Achillea millefolium decreased IL-17 secretion but did not affect IFN-γ and IL-10 secretion by allogeneic CD4(+) T cells. CONCLUSIONS: Aqueous extract from Menyanthes trifoliate induces a suppressive phenotype of DCs that has reduced capacity to induce Th1 and Th17 stimulation of allogeneic CD4(+) T cells, whereas aqueous extract from Achillea millefolium reduces the capacity of DCs to induce a Th17 response.

Ethanol extract from birch bark (Betula pubescens) suppresses human dendritic cell mediated Th1 responses and directs it towards a Th17 regulatory response in vitro.

Extracts and fractions from birch bark have been used to treat various diseases, such as skin disorders and rheumatism, and for analgesic effects. Results from studies in vitro and in vivo have shown that birch bark extracts can have immunoregulatory effects. These effects have mainly been attributed to the various triterpenes found in birch bark. The effects of birch bark from Betula pubescens on immune responses have not been reported. Ethanol extract was prepared from dry birch bark (DBBEE) and five fractions made using various ratios of dichloromethane and methanol (fractions I-V). Human monocyte-derived dendritic cells (DCs) were matured with or without DBBEE or fractions I-V at several concentrations. The effects of the extract and fractions on DC maturation were determined by measuring cytokine secretion by ELISA and expression of surface molecules by flow cytometry. DBBEE and fractions III and IV reduced DC secretion of IL-6, IL-10 and IL-12p40 and expression of CD83, CD86, CCR7 and DC-SIGN compared with control DCs. Proliferation of allogeneic CD4(+) T cells co-cultured with DCs matured with fraction IV, as measured by (3)H-thymidine incorporation, was similar to proliferation of allogeneic CD4(+) T cells co-cultured with control DCs. However, IFN-γ secretion was reduced and IL-10 and IL-17 secretion was increased, a cytokine profile consistent with a Th17 regulatory phenotype. These results indicate that bark from Betula pubescens contains compound(s) that can modulate DCs so that their interaction with T cells leads to an immunoregulatory response.