Maturation of monocyte-derived dendritic cells by Hochu-ekki-to, a traditional Japanese herbal medicine

To investigate the immunological effect of the traditional Japanese herbal medicine (kampo), Hochu-ekki-to (HOT), on dendritic cells (DC), we examined in vitro if HOT would stimulate the maturation process of human monocyte-derived DC as do TNF-alpha and LPS. Monocytes from a healthy volunteer were cultured in the presence of IL-4 and GM-CSF, and the generated immature DC were stimulated with HOT, TNF-alpha, or LPS (HOT-DC, TNF-DC, and LPS-DC, respectively) for 2 days. Flow cytometric analysis showed that HOT stimulated DC to express the surface maturation markers CD80, CD83, and CD86 dose-dependently and that the up-regulation level was identical to TNF-alpha and LPS. The antigen-uptake capacity of HOT-DC was determined by FITC-labeled albumin uptake. HOT-DC lost albumin uptake capacity comparable to LPS-DC, indicating DC maturity. IL-12 (p70) production by HOT-DC and TNF-DC was not increased in comparison with LPS-DC. The antigen-presenting capacity of HOT-DC as analyzed by allogeneic T cell proliferation was significantly increased in comparison with immature DC and was identical to LPS-DC. These results demonstrate that HOT stimulates DC maturation as well as the other known maturation factors, despite low IL-12 production, and suggests the possibility that DC maturation by HOT can play an important role in the improvement of the immunoregulatory function in patients with impaired host defense.     

Water extract of Cordyceps militaris enhances maturation of murine bone marrow-derived dendritic cells in vitro

Water extract (WE) of Cordyceps militaris has been reported to produce antitumor and immunomodulatory activities in vivo and in vitro. However, the therapeutic mechanism has not been known. In this study, we investigated whether water extract of C. militaris induces the phenotypic and functional maturation of dendritic cells (DC). It profoundly increased CD40, CD54, CD80, CD86, and MHC class II expression in murine bone marrow (BM)-derived myeloid DC. Endocytosis was assessed by the uptake of FITC-dextran and FITC-albumin. The ability of unstimulated DC (UT-DC) to uptake dextran and albumin was higher than that of WE- or LPS-stimulated DC (LPS-DC). Also, UT-DC secreted a low concentration of IL-12, while WE- or LPS-DC secreted higher levels of IL-12 than UT-DC. WE not only formed morphologically mature DC and clusters, but also induced predominantly functional maturation. Moreover, WE is shown to promote the cytotoxicity of specific-cytotoxic T lymphocyte (CTL) induced by DC which were pulsed with P815 tumor-lysate during the stage of antigen presentation. These results suggest that DC maturation by WE can play a critical role in the improvement of the immunoregulatory function in patients with impaired host defense.     

Maturation of dendritic cells induced by Candida beta-D-glucan

We investigated whether Candida beta-D-glucan (CSBG) alters the maturation of dendritic cells (DCs). DC phenotypes were analyzed using FACScan. The expression of surface molecules, including major histocompatibility complex (MHC) classes I and II, as well as CD80 and CD86, increased on DCs that were stimulated with lipopolysaccaride (DCs/LPS), in comparison with unstimulated bone marrow-derived DCs (BM-DCs). Furthermore, the level of surface molecule expression on DCs stimulated with CSBG (DCs/CSBG) was between that of DCs and DCs/LPS. Phagocytosis was assessed by the uptake of FITC-dextran. There were no differences in the uptake of dextran among DCs/LPS and DCs/CSBG. The ability of BM-DCs to uptake dextran was higher than that of DCs/LPS and DCs/CSBG. We analyzed the concentration of IL-12 secreted by DCs using ELISA. BM-DCs secreted a low concentration of IL-12, while DCs/LPS and DCs/CSBG secreted higher levels of IL-12 than BM-DCs. There were no remarkable differences in the concentrations of IL-12 produced by DCs/LPS and DCs/CSBG. This data suggests that CSBG may augment DC maturation.     

Effect of pentoxifylline on differentiation and maturation of human monocyte-derived dendritic cells in vitro

Pentoxifylline (PTX) is a drug used for the treatment of vascular disorders, but it also has a positive therapeutic effect in experimental models of some autoimmune diseases. In this work, we studied the effect of PTX on human monocyte-derived dendritic cells (MDDCs). Immature MDDCs were generated in vitro from monocytes in the presence of recombinant human granulocyte macrophage-colony stimulating factor (rhGM-CSF) and recombinant human interleukin-4 (rhIL-4), while mature MDDCs were obtained by cultivation of immature MDDCs with lipopolysaccharide (LPS). PTX (200 micro g/ml) was added at the beginning of cell cultivation. We found that PTX significantly impaired differentiation and function of immature MDDCs, as judged by the reduced allostimulatory activity of these cells on allogeneic T cells and down-regulation of costimulatory and adhesion molecules, such as CD86, CD40 and CD54. The maturation of MDDCs in the presence of PTX and LPS was characterized by the decreased expression of maturation marker CD83 and costimulatory molecule CD86, as well as lower stimulation of alloreactive T cells compared to the control MDDCs cultivated with LPS alone. PTX-treated MDDCs which were induced to mature with LPS produced lower levels of TNF-alpha, IL-12 and IL-18 and higher levels of IL-10 than corresponding control MDDCs. PTX did not significantly alter endocytosis of dextran by both immature and mature MDDCs. Cumulatively, our results show for the first time that PTX might impair differentiation, maturation and function of human MDDCs in vitro, suggesting an additional mechanism of its immunomodulatory activity.     

Effects of vasoactive intestinal peptide on phenotypic and functional maturation of dendritic cells

The present study was designed to investigate the effects of vasoactive intestinal peptide (VIP) on differentiation, maturation of dendritic cells (DCs) in vitro. DCs were derived from the murine bone marrow hemopoietic progenitor cells by culturing in RPMI 1640 complete medium supplemented with GM-CSF and IL-4 in the presence or absence of various concentrations of vasoactive intestinal peptide (VIP) and lipopolysaccharide (LPS). The phenotype of DCs was analyzed by flow cytometry. Mixed leukocyte reaction (MLR) was employed to measure the capacity of DC to stimulate the allogeneic T cells. IL-12p70 secretion by DC was examined by ELISA. In the absence of LPS, VIP, in a dose dependent manner, up-regulated the expression of CD80, CD86, CD54 and CD40, but down-regulated the expression of MHC class II molecule (Ia(b)). In the presence of LPS, VIP also dose dependently up-regulated the expression of CD80, CD86, CD54 and CD40, and down-regulated the expression of Ia(b). The capacity to stimulate alloreactive T cells and the production of IL-12p70 by DC were significantly augmented by VIP when compared with VIP-untreated DCs. These data suggest that VIP could promote the phenotypic and functional maturation of DCs, hereby regulating the type and outcome of the conducting immune response.     

Sinomenine promotes differentiation but impedes maturation and co-stimulatory molecule expression of human monocyte-derived dendritic cells

Dendritic cells (DC) excel at presenting antigen to T cells and thus make a key contribution to the induction of primary and secondary immune responses. Sinomenine has been used for centuries in the treatment of patients with autoimmune diseases as it possesses immunosuppressive and anti-inflammatory activities. However, the effect of sinomenine on the differentiation, maturation, and functionality of DC derived from monocytes has not been studied. We show here that DC differentiation is promoted when monocytes are treated with GM-CSF and IL-4 (IL-4) in the presence of sinomenine (200 microg/ml), as evidenced by the upregulation of CD1a while CD14 was decreased. In addition, incubation of immature DC with sinomenine significantly blunted lipopolysaccharide (LPS)-induced DC maturation, as shown by the reduction of expression of the maturation marker CD83 and co-stimulatory molecules, including CD86, B7-H1, and CD40. Moreover, sinomenine also prevented decreases in antigen (FITC-Dextran or Lucifer Yellow) uptake by LPS-treated DC. Mixed lymphocyte reactions (MLRs) revealed that sinomenine-treated DC impede the secretion of the cytokines IL-2 and IFN-gamma by co-cultured CD4(+) T cells. Therefore, modulation of DC differentiation, maturation, and functionality by sinomenine is of potential relevance to its immunomodulatory effects in controlling specific immune responses in autoimmune diseases, transplantation, and other immune-mediated conditions.     

A sea urchin lectin, SUL-1, from the Toxopneustid sea urchin induces DC maturation from human monocyte and drives Th1 polarization in vitro

The sea urchin Toxopneustes pileolus belonging to the family Toxopneustidae, they have well-developed globiferous pedicellariae with pharmacologically active substances. We have purified a novel sea urchin lectin-1 (SUL-1) from the large globiferous pedicellariae of T. pileolus. Dendritic cells (DC) are professional APC and play a pivotal role in controlling immune responses. This study investigated whether SUL-1 can drive DC maturation from human immature monocyte-derived DC in vitro. Human monocytes were cultured with GM-CSF and IL-4 for 6 days followed by another 1 day in the presence of SUL-1 or LPS. DC harvested on day 7 were examined using functional assays. The expression levels of CD1a, CD80, CD83, CD86 and HLA-DR as expressed by mean fluorescence intensity (MFI) on DC differentiated from immature DC after culture with 1.0 microg/ml of SUL-1 for 1 day were enhanced and decreased endocytic activity. SUL-1-treated DC also displayed enhanced T cell stimulatory capacity in an MLR, as measured by T cell proliferation. Cell surface expression of CD80, CD83 and CD86 on SUL-1-treated DC was inhibited by anti-DC-SIGN mAb, while anti-DC-SIGN mAb had no influence on allogeneic T cell proliferation by SUL-1-treated DC. DC differentiated with SUL-1 induced the differentiation of na?ve T cell towards a helper T cell type 1 (Th1) response at DC/T (1:5) cells ratio depending on IL-12 secretion. In CTL assay, the production of IFN-gamma and 51Cr release on SUL-1-treated DC were more augmented than of immature DC or LPS-treated DC. SUL-1-treated DC expressed CCR7 and had a high migration to MIP-3beta. Intracellular Ca2+ mobilization in SUL-1-treated DC was also induced by MIP-3beta. These results suggest that SUL-1 bindings to DC-SIGN on surface of immature DC may lead to differentiate DC from immature DC. Moreover, it suggests that SUL-1 may be used on DC-based vaccines for cancer immunotherapy.     

Biomedical nanoparticles modulate specific CD4+ T cell stimulation by inhibition of antigen processing in dendritic cells

Understanding how nanoparticles may affect immune responses is an essential prerequisite to developing novel clinical applications. To investigate nanoparticle-dependent outcomes on immune responses, dendritic cells (DCs) were treated with model biomedical poly(vinylalcohol)-coated super-paramagnetic iron oxide nanoparticles (PVA-SPIONs). PVA-SPIONs uptake by human monocyte-derived DCs (MDDCs) was analyzed by flow cytometry (FACS) and advanced imaging techniques. Viability, activation, function, and stimulatory capacity of MDDCs were assessed by FACS and an in vitro CD4+ T cell assay. PVA-SPION uptake was dose-dependent, decreased by lipopolysaccharide (LPS)-induced MDDC maturation at higher particle concentrations, and was inhibited by cytochalasin D pre-treatment. PVA-SPIONs did not alter surface marker expression (CD80, CD83, CD86, myeloid/plasmacytoid DC markers) or antigen-uptake, but decreased the capacity of MDDCs to process antigen, stimulate CD4+ T cells, and induce cytokines. The decreased antigen processing and CD4+ T cell stimulation capability of MDDCs following PVA-SPION treatment suggests that MDDCs may revert to a more functionally immature state following particle exposure.     

Resveratrol inhibits phenotypic and functional maturation of murine bone marrow-derived dendritic cells

This study investigated the effects of resveratrol, a natural polyphenol found in grapes and grape products such as wine and having a wide range of biological and pharmacological activities effecting on the phenotypic and functional maturation of bone marrow (BM)-derived dendritic cells (DC). Resveratrol inhibited the expression of costimulatory molecules (CD80 and CD86), and major histocompatibility complex (MHC) classes I and II significantly, and had the same effect dose-dependently on DC. Resveratrol also significantly suppressed the ability of BM-DC to produce intracellular IL-12 p40/p70 and secretory IL-12 p70 in response to lipopolysaccharides (LPS) stimulation. Resveratrol-treated DC were highly efficient in antigen capture via mannose receptor-mediated endocytosis. Also, they were poor stimulators of na?ve allogeneic T-cell proliferation and induced lower levels of IL-2 in responding T cells. These results indicate the immunosuppressive properties of resveratrol, which may be therapeutically useful in controlling chronic immune and/or inflammatory diseases through the down-regulation of DC differentiation and maturation.     

Lead effects on development and function of bone marrow-derived dendritic cells promote Th2 immune responses

Although lead (Pb) has significant effects on the development and function of macrophages, B cells, and T cells and has been suggested to promote allergic asthma in mice and humans, Pb modulation of bone marrow (BM)-derived dendritic cells (DCs) and the resultant DC effects on Th1 and Th2 development have not been examined. Accordingly, we cultured BM cells with murine granulocyte macrophage-colony stimulating factor (mGM-CSF)+/-PbCl(2). At day 10, culture supernatant (SN) and non-adherent cells were harvested for analysis. Additionally, day 10 non-adherent BM-DCs were harvested and recultured with mGM-CSF+LPS+/-Pb for 2 days. The day 10 Pb exposure significantly inhibited BM-DC generation, based on CD11c expression. Although fewer DCs were generated with Pb, the existing Pb-exposed DCs had significantly greater MHC-II expression than did the non-Pb-exposed DCs. However, these differences diminished upon LPS stimulation. After LPS stimulation, CD80, CD86, CD40, CD54, and MHC-II were all up-regulated on both Pb-DCs and DCs, but Pb-DCs expressed significantly less CD80 than did DCs. The CD86:CD80 ratio suggests a Pb-DC potential for Th2 cell development. After LPS stimulation, IL-6, IL-10, IL-12 (p70), and TNF-alpha levels significantly increased with both Pb-DCs and DCs, but Pb-DCs produced significantly less cytokines than did DCs, except for IL-10, which further supports Pb-DC preferential skewing toward type-2 immunity. In vitro studies confirm that Pb-DCs have the ability to polarize antigen-specific T cells to Th2 cells. Pb-DCs also enhanced allogeneic and autologous T cell proliferation in vitro, and in vivo studies suggested that Pb-DCs inhibited Th1 effects on humoral and cell-mediated immunity. The Pb effect was mainly on DCs, rather than on T cells, and Pb's modification of DC function appears to be the main cause of Pb's promotion of type-2-related immunity, which may relate to Pb's enhanced activation of the Erk/MAP kinase pathway.     

Acemannan purified from Aloe vera induces phenotypic and functional maturation of immature dendritic cells.

Acemannan, a major carbohydrate fraction of Aloe vera gel, has been known to have antiviral and antitumoral activities in vivo through activation of immune responses. The present study was set out to define the immunomodulatory activity of acemannan on dendritic cells (DCs), which are the most important accessory cells for the initiation of primary immune responses. Immature DCs were generated from mouse bone marrow (BM) cells by culturing in a medium supplemented with GM-CSF and IL-4, and then stimulated with acemannan, sulfated acemannan, and LPS, respectively. The resultant DCs were examined for phenotypic and functional properties. Phenotypic analysis for the expression of class II MHC molecules and major co-stimulatory molecules such as B7-1, B7-2, CD40 and CD54 confirmed that acemannan could induce maturation of immature DCs. Functional maturation of immature DCs was supported by increased allogeneic mixed lymphocyte reaction (MLR) and IL-12 production. The differentiation-inducing activity of acemannan was almost completely abolished by chemical sulfation. Based on these results, we propose that the adjuvant activity of acemannan is at least in part due to its capacity to promote differentiation of immature DCs.     

Effect of piceatannol in human monocyte-derived dendritic cells in vitro

Piceatannol is an anti-inflammatory, immunomodulatory, and antiproliferative stilbene that has been shown to interfere with the cytokine signaling pathway. Dendritic cells (DCs) play a pivotal in the initiation of T-cell-mediated immune responses, making them an attractive cellular adjuvant for use in cancer vaccines. This study investigated the effect of piceatannol on the phenotypic and functional maturation of human monocyte-derived DCs in vitro. Human monocytes were cultured with GM-CSF and IL-4 for 6 days, followed by another 2 days in the presence of piceatannol or LPS. DCs harvested on day 8 were examined using functional assays. The expression levels of CD1a, CD80, CD83, and CD86 as expressed by mean fluorescence intensity (MFI) on DCs differentiated from immature DCs after culture with 1 muM of piceatannol for 2 days were enhanced and decreased endocytic activity. Piceatannol-treated DCs also displayed enhanced T-cell stimulatory capacity in a MLR, as measured by T-cell proliferation. Similar results were obtained with DCs differentiated with LPS from immature DCs. However, piceatannol did not inhibit phenotypic and functional maturation induced by LPS from immature DCs. Piceatannol-treated DCs induced the differentiation of naive T cells towards a helper T-cell type 1 (Th1) response at DCs/T (1:5) cells ratio depending on IL-12 secretion. These results demonstrate that piceatannol may be used on DC-based vaccine for cancer immunotherapy.     

Matrine derivate MASM suppresses LPS-induced phenotypic and functional maturation of murine bone marrow-derived dendritic cells

Dendritic cell (DC) maturation process is a crucial step for the development of T cell immune responses and immune tolerance. In this study, we evaluated MASM, a novel derivative of the natural compound matrine that possesses a significant anti-inflammatory and immune-regulating property, for its efficacy to inhibit lipopolysaccharides (LPS)-induced maturation of murine bone marrow-derived dendritic cells. Here we show that MASM profoundly suppresses LPS-induced phenotypic and functional DC maturation. MASM inhibited LPS-induced expression of costimulatory molecules CD80 and CD86 in a concentration-dependent manner. MASM also attenuated LPS-induced IL-12p70, TNF-α, IL-6 and NO release of DCs. The MASM-treated DCs were highly efficient at antigen capture via mannose receptor-mediated endocytosis but showed weak stimulatory capacity for allogeneic T cell proliferation. Furthermore, MASM inhibited LPS-induced PI3K/Akt, MAPK and NF-κB pathways. These novel findings provide new insight into the immunopharmacological role of MASM in impacting on the DCs.     

D-pinitol inhibits Th1 polarization via the suppression of dendritic cells

d-pinitol has been demonstrated to exert insulin-like and anti-inflammatory effects. However, the effects of the maturation and immunostimulatory functions of dendritic cells (DC) remain to be clearly elucidated. In this study, we have attempted to determine whether d-pinitol regulates surface molecule expression, cytokine production, endocytosis capacity, and underlying signaling pathways in murine bone marrow-derived DC. We also attempted to ascertain whether d-pinitol could influence Th1/Th2 immune response in vivo. The DC used in this study were derived from murine bone marrow cells, and were used as immature or LPS-stimulated mature DC. The DC were then assessed with regard to surface molecule expression, dextran-FITC uptake, cytokine production, capacity to induce T-cell differentiation, and underlying signaling pathways. d-pinitol was shown to significantly inhibit CD80, CD86, MHC class I, and MHC class II expression in the LPS-stimulated mature DC. The DC also evidenced impaired IL-12 expression and IFN-gamma production. The d-pinitol-treated DC were found to be highly efficient in regards to Ag capture via mannose receptor-mediated endocytosis. d-pinitol was also demonstrated to inhibit LPS-induced MAPKs activation and NF-kappaB nuclear translocation. Moreover, the d-pinitol-treated DC manifested impaired induction of Th1 responses, and normal cell-mediated immune responses. These novel findings provide new insight into the immunopharmacological role of d-pinitol in terms of its effects on DC. These findings also broaden current perspectives concerning our understanding of the immunopharmacological functions of d-pinitol, and have ramifications for the development of therapeutic adjuvants for the treatment of DC-related acute and chronic diseases.     

Regulation on maturation and function of dendritic cells by Astragalus mongholicus polysaccharides

Astragalus mongholicus polysaccharides(ASP) isolated from one of the Chinese herbs-A. mongholicus which are known to have a variety of immunomodulatory activity. However, little is known about their immunomodulatory effects on murine bone marrow (BM)-derived dendritic cells (DC). DC are professional antigen presenting cells, which are pivotal for initiation of primary immune response. In this study, the regulatory effects of ASP on maturation and function of cultured murine BM-derived DC were investigated in vitro. ASP (10, 50, 100, 250 microg/ml) could increase the co-expression of CD-11c and MHC class II molecules on DC surface, and the 100 microg/ml is the optimal dose. The ability of unstimulated DC to uptake FITC-dextran was higher than that of ASP- or LPS-treated DC. We analyzed the concentration of IL-12 secreted by DC using ELISA. ASP-treated DC secreted a higher level of IL-12 than untreated DC. And ASP- or LPS-treated DC displayed a more mature morphology, with long protrusions, while untreated-DC displayed shorter protrusions than stimulated DC.     

A novel role for RGMa in modulation of bone marrow-derived dendritic cells maturation induced by lipopolysaccharide

Repulsive guidance molecule a (RGMa) is known to mediate immune responses and has been indicated to modulates T cell activation and autoimmune diseases by dendritic cells (DCs), which hints its significant function in the latter cells. The aim of our study, therefore, was to evaluate the function of RGMa in DC maturation. We found that small interfering RNA (siRNA) successfully silenced the expression of RGMa in DCs. Even after LPS stimulation, RGMa-silenced DCs displayed an immature morphology, characterized by small, round cells with a few cell processes and organelles, and many pinocytotic vesicles. In the presence of LPS, RGMa siRNA transfection markedly reduced levels of CD80, CD86, CD40, and MHC II expression, as well as the secretion of IL-12p70 and TNF-α. With LPS treatment, RGMa siRNA-transfected DCs also showed increased levels of IL-10 and endocytosis. Moreover, in the presence of LPS, RGMa siRNA-transfected DCs displayed a low ability to induce T cell proliferation and differentiation, compared with negative control (NTi)-transfected or control DCs (p < 0.05 for both). We conclude that after LPS stimulation, RGMa siRNA-transfected DCs show immunoregulatory and tolerogenic characteristics, which provides new insights into the immune system.     

Promoting effect of polysaccharide isolated from Mori fructus on dendritic cell maturation

Maturation of dendritic cells (DCs) is usually attenuated in the tumor microenvironment, which is an important immunological problem in DC-based immunotherapy of cancer. In this study, we report the effect of a Mori fructus polysaccharide (MFP) on DC maturation. MFP was treated to DCs generated from mouse BM cells. MFP induced phenotypic maturation of DCs, as proven by the increased expression of CD40, CD80/86, and MHC-I/II molecules. MFP induced functional maturation of DCs, in that MFP increased the expression of IL-12, IL-1β, TNF-α, and IFN-β, decreased antigen capture capacity, and enhanced allogenic T cell stimulation. MFP efficiently induced maturation of DCs from C3H/HeN mice having normal toll-like receptor4 (TLR4), but not DCs from C3H/HeJ mice having mutated TLR4, suggesting that TLR4 might be one of the membrane receptors of MFP. As a mechanism of action, MFP increased phosphorylation of mitogen-activated protein kinase (MAPKs), and nuclear translocation of NF-κB p65 subunit, which were important signal molecules downstream from TLR4. These data suggest that MFP induces DC maturation through TLR4 and MFP can be used as an adjuvant in DC-based cancer immunotherapy.     

他克莫司对体外培养的大鼠树突状细胞成熟过程及其同种免疫刺激活性的影响(英文)

目的研究他克莫司对体外培养的大鼠树突状细胞(DC)成熟过程和同种刺激活性的影响。方法20只大鼠随机分为对照组、他克莫司、脂多糖(LPS)及LPS+他克莫司组,分别取骨髓细胞,加入粒细胞巨噬细胞集落刺激因子和白细胞介素4(IL-4)培养6d,收集贴壁细胞即DC。对照组不再加其他试剂,他克莫司组在开始培养时即加入他克莫司10μg·L-1,LPS组在细胞培养结束前18h加入LPS100μg·L-1,他克莫司+LPS组分别按上述要求加入他克莫司和LPS。用流式细胞术测定DC表面CD80和CD86的表达,ELISA方法检测其培养上清IL-12的浓度,用混合淋巴细胞培养法观察其对同种T细胞的刺激能力。结果与对照组比较,LPS刺激后,DC表面CD80和CD86表达明显增加,培养上清中IL-12浓度升高,其刺激同种T细胞的能力增强。与对照组和LPS组比较,他克莫司可使DC表面CD80和CD86表达明显降低,IL-12分泌减少,刺激同种T细胞的能力减弱。结论他克莫司可抑制体外培养的DC成熟及其同种刺激活性。     

Apigenin inhibits immunostimulatory function of dendritic cells: Implication of immunotherapeutic adjuvant

Apigenin, one of the most common flavonoids, has been shown to possess anti-inflammatory, anticarcinogenic, and free radical-scavenging properties. However, the influence of apigenin on the immunostimulatory effects and maturation of dendritic cells (DC) remains, for the most part, unknown. In this study, we have attempted to ascertain whether apigenin influences the expression of surface molecules, dextran uptake, cytokine production, and T-cell differentiation as well as the signaling pathways underlying these phenomena in murine bone marrow-derived DC. In the presence of apigenin, CD80, CD86, and major histocompatibility complex class I and II molecules, expressions on DC were significantly suppressed, and lipopolysaccharide (LPS)-induced interleukin (IL)-12 expression was impaired. The DC proved highly efficient at antigen capture, as evidenced by the observation of mannose receptor-mediated endocytosis in the presence of apigenin. The LPS-induced activation of mitogen-activated protein kinase, the nuclear translocation of its nuclear factor-kappaB p65 subunit, and the induction of the T-helper 1 response were all impaired in the presence of apigenin, whereas the cell-mediated immune response remained normal. These findings provide new insight into the immunopharmacological functions of apigenin and its effects on DC, and they may also prove useful in the development of adjuvant therapies for individuals suffering from acute or chronic DC-associated diseases.     

Angelan isolated from Angelica gigas Nakai induces dendritic cell maturation through toll-like receptor 4

During the evolution of neoplastic diseases, dendritic cell (DC) functions are usually attenuated, and this presents a problem to DC-based immunotherapies against cancer. Here, we investigated the effects of angelan, an acidic polysaccharide isolated from Angelica gigas Nakai, on DC maturation. Angelan efficiently increased the maturation of tlr4(+/+) DCs from C57BL/6 and C3H/HeN mice, but not tlr4(-/-) DCs from C3H/HeJ mice. Phenotypic maturation was confirmed by the elevated expressions of CD80, CD86, and MHC-class II molecules, and functional maturation by increased IL-12 production, enhanced allogenic T cell stimulation, and decreased endocytosis. Angelan was found to activate ERK and NF-kappaB, which are signaling molecules down-stream of toll-like receptor-4 (TLR4) receptors. Angelan-treated mature DC more effectively inhibited B16F10 tumor growth than immature DCs in syngenic murine tumor model. These results indicate that angelan induces DC maturation via TLR4 signaling pathways and suggest the possible use of angelan in DC-based immunotherapies.