Activation of dendritic cells by low molecular weight oyster polysaccharides

Dendritic cells play a primary role in antigen presentation to CD4⁺ T cells, which initiate acquired immune responses. Therefore, determining positive modulators of dendritic cell activation to improve therapeutic approaches for cancer treatment might be useful. We here investigated the effects of low molecular weight oyster polysaccharides (LMW-OPS) on bone marrow-derived dendritic cells (BMDCs) obtained from mice. LMW-OPS increased the surface expression of major histocompatibility complex class II (MHC-II), CD40 and CD86 in BMDCs and induced the secretion of tumour necrosis factor (TNF)-α and interleukin (IL)-12, which were significantly decreased in the BMDCs derived from MyD88^−/− mice but not from the lipopolysaccharide-resistant C3H/HeJ mice. BMDCs treated with LMW-OPS augmented allogeneic CD4⁺ T cell expansion and enhanced secretion of IL-2 and interferon (IFN)-γ but not IL-4. LMW-OPS induced significant increases in ERK and p38 MAPK phosphorylation, but not c-Jun N-terminal kinase (JNK) phosphorylation, in BMDCs. Our results indicate that, in part, LMW-OPS can induce maturation of BMDCs in a MyD88-dependent and Toll-like receptor (TLR) 4-independent manner. LMW-OPS may enhance acquired immunity by modulating the function of dendritic cells.     

Dendritic cells transfected with indoleamine 2,3-dioxygenase gene suppressed acute rejection of cardiac allograft

BackgroundImmunomodulation by indoleamine 2,3-dioxygenase (IDO) has been documented in many studies yet its underlying mechanisms remain undefined, especially in solid organ transplantation. Recent research demonstrated that the active expression of IDO in dendritic cells (DCs) regulates immune reaction. This study assessed whether DCs transfected with IDO gene inhibit T cells responses and suppress cardiac allograft rejection.MethodsAdenovirus vector containing IDO gene was transfected into DCs to obtain IDO-positive DCs (IDO⁺ DCs). To evaluate the effect of IDO⁺ DCs on T cells in vitro, CD4⁺ T cell proliferation and apoptosis was assessed in mixed lymphocyte reactions and measured by flow cytometry, respectively. IDO⁺ DCs from C57BL/6 mice were injected into BALB/c recipients before heterotopic cardiac transplantation.ResultsSupernatant fluids from cultures of IDO⁺ DCs had decreased tryptophan and increased kynurenine levels, reflecting IDO activity. IDO⁺ DCs suppressed CD4⁺ T cell responses in vitro, as reflected by decreased proliferation and increased apoptosis. In the transplant model, IDO⁺ DCs prolonged survival and alleviated rejection of cardiac allograft in recipients injected with IDO⁺ DCs. In vivo, IDO⁺ DCs also significantly impaired CD4⁺ T cell responses promoting increased apoptosis and a Th2-dominant cytokine shift.ConclusionsIDO overexpression in DCs suppressed T cells alloresponses in vitro, and IDO⁺ DCs attenuated acute allograft rejection in vivo. Regulation of tryptophan catabolism by means of IDO overexpression in DCs may be a useful approach in cardiac transplantation and immunological tolerance.     

Triptolide regulates T cell-mediated immunity via induction of CD11c dendritic cell differentiation

Triptolide(TPT) isolated from one of the Chinese herbs, Tripterygium wilfordii Hook. F. (TWHF), are known to have a variety of immunomodulatory activities. This study was performed to investigate the effect of TPT on the differentiation of splenic DCs and its influence on T cell-mediated immunity regarding to DC subsets CD11c^lowI-a/e^lowCD45RB⁺(CD11c^low DCs) and CD11c^highI-a/e^highCD45RB^- (CD11c^high DCs) in male C57BL/6 mice spleens in vitro. The percentage of CD11c^low DCs was significantly increased after treatment with TPT compared to their counterparts (CD11c^high DCs). It was found that unlike the gradually decreasing interleukin (IL)-12 secretion of CD11c^high DCs induced by TPT, CD11c^low DCs showed a obvious dose-dependent response between the increasing of IL-10 production and TPT stimulation. After treatment with anti-IL-12R or anti-IL-10 monoclonal antibody in CD4⁺ T cells + CD11c^high DCs or CD11c^low DCs mixed lymphocyte reaction, the induction of these DCs on T cells was inhibited dramatically. These data demonstrated that TPT might induce the differentiation of splenic DCs to CD11c^low DCs followed by shifting of Th1 to Th2 with enhancement of T lymphocyte immune function in vitro.     

MicroRNA-106b regulates pro-allergic properties of dendritic cells and Th2 polarisation by targeting early growth response-2 in vitro

Recent evidence has suggested that miRNA is implicated in the immune response of allergic and inflammatory diseases. However, little is known about its role in the mechanism that underlies the establishment of pro-allergic DCs in allergic rhinitis is not fully understood. This study assessed whether and how microRNA (miR)-106b regulates the pro-allergic properties of DCs upon allergen stimulation in vitro. Bone marrow-derived dendritic cells (BMDCs) were generated and stimulated with ovalbumin (OVA) to identify the miRNA expression profile. After transfection with miR-106b mimics and inhibitors OVA-activated BMDCs were further evaluated for surface marker expression using flow cytometry, cytokine production using ELISA and subsequent effects on Th2 cell polarisation using flow cytometry. Moreover, the upstream controllers and potential target proteins of miR-106b were examined in a western blot analysis. Results showed that MiR-106b expression was significantly inhibited in activated BMDCs upon OVA stimulation (p < 0.05). Surface marker expression (e.g., MHC class II, CD80 and CD86) was significantly upregulated after the transfection of an miR-106b inhibitor (p < 0.05), and the proportion of GATA-3⁺ T cells was significantly increased among CD4⁺ T cells that were cocultured with miR-106b inhibitor-pretreated BMDCs (p < 0.05). Conversely, IL-12 production from OVA-activated BMDCs and the proportion of T-bet⁺ T cells increased significantly in a coculture of CD4⁺ T cells and miR-106b mimics-transfected BMDCs (p < 0.05). The early growth response (Egr)-2 was identified via luciferase reporter assays as a target gene of miR-106b, and significant Egr-2 upregulation was observed in OVA-activated BMDCs following transfection with a miR-106b inhibitor (p < 0.05). In conclusion, our results suggest that miR-106b negatively regulates the pro-allergic properties of BMDCs and subsequent Th2 polarisation upon OVA stimulation and might represent a promising therapeutic target for allergic inflammation.     

Ferritin protein cage nanoparticles as versatile antigen delivery nanoplatforms for dendritic cell (DC)-based vaccine development

We utilized ferritin protein cage nanoparticles (FPCN) as antigen delivery nanoplatforms for DC-based vaccine development and investigated DC-mediated antigen-specific immune responses. Antigenic peptides, OT-1 (SIINFEKL) or OT-2 (ISQAVHAAHAEINEAGR) which are derived from ovalbumin, were genetically introduced either onto the exterior surface or into the interior cavity of FPCN. FPCN carrying antigenic peptides (OT-1-FPCN and OT-2-FPCN) were effectively delivered to DCs and processed within endosomes. Delivered antigenic peptides, OT-1 or OT-2, to DCs successfully induced antigen-specific CD8⁺ or CD4⁺ T cell proliferations both in vitro and in vivo. Naïve mice immunized with OT-1-FPCN efficiently differentiated OT-1 specific CD8⁺ T cells into functional effector cytotoxic T cells resulting in selective killing of antigen-specific target cells. Effective differentiation of proliferated OT-2 specific CD4⁺ T cells into functional CD4⁺ Th1 and Th2 cells was confirmed with the productions of IFN-γ/IL-2 and IL-10/IL-13 cytokines, respectively.From the Clinical EditorIn this study, the authors utilized ferritin protein cage nanoparticles as antigen delivery nanoplatforms for dendritic cell-based vaccine development and investigated DC-mediated antigen-specific immune responses using strong model antigens derived from ovalbumin, suggesting potential future clinical applicability of this or similar techniques.     

Exploring the immunopotentiation of Chinese yam polysaccharide poly(lactic-co-glycolic acid) nanoparticles in an ovalbumin vaccine formulation in vivo

Biocompatible and biodegradable poly(lactic-co-glycolic acid) (PLGA) has been approved by the US Food and Drug Administration and has frequently been used to develop potential vaccine delivery systems. The immunoregulation and immunopotentiation of Chinese yam polysaccharide (CYP) have been widely demonstrated. In the current study, cell uptake mechanisms in dendritic cells (DCs) were monitored in vitro using confocal laser scanning microscopy, transmission electron microscopy, and flow cytometry. To study a CYP-PLGA nanoparticle-adjuvanted delivery system, CYP and ovalbumin (OVA) were encapsulated in PLGA nanoparticles (CYPPs) to act as a vaccine, and the formulation was tested in immunized mice. The CYPPs more easily underwent uptake by DCs in vitro, and CYPP/OVA could stimulate more effective antigen-specific immune responses than any of the single-component formulations in vivo. Mice immunized using CYPP/OVA exhibited more secretion of OVA-specific IgG antibodies, better proliferation, and higher cytokine secretion by splenocytes and significant activation of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells. Overall, the CYPP/OVA formulation produced a stronger humoral and cellular immune response and a mixed Th1/Th2 immune response with a greater Th1 bias in comparison with the other formulations. In conclusion, the data demonstrate that the CYPP-adjuvanted delivery system has the potential to strengthen immune responses and lay the foundation for novel adjuvant design.     

Interleukin-7 promotes lung-resident CD14+ monocytes activity in patients with lung squamous carcinoma

Interleukin (IL)-7 enhances cytokines secretion by CD14⁺ monocytes, and induces recruitment of monocytes to endothelium. As an important regulator to different types of immune cells, the role of IL-7 in modulation of CD14⁺ monocytes is still not fully elucidated. Thus, the aim of current study was to investigate the immunoregulatory activity of IL-7 to peripheral and lung-resident CD14⁺ monocytes in lung squamous carcinoma patients. Thirty-seven lung squamous carcinoma patients and eighteen healthy individuals were enrolled. CD14⁺ monocytes and CD4⁺ T cells were purified from both peripheral bloods and bronchoalveolar lavage fluids (BALF). IL-7 expression in plasma and BALF was measured by ELISA, and CD127 expression in peripheral and lung-resident CD14⁺ monocytes was investigated by real-time PCR and flow cytometry, respectively. Cellular proliferation, cytokine production, and molecules in IL-7 signaling pathway was assessed in CD14⁺ monocytes in response to IL-7 stimulation. IL-7-induced CD14⁺ monocytes activity to CD4⁺ T cells was also assessed in direct and indirect contact co-culture system. There were no remarkable differences of plasma IL-7 concentration or CD127 level between healthy individuals and lung squamous carcinoma patients. However, IL-7 expression was significantly reduced in BALF from tumor site in squamous carcinoma patients, especially in stage III and IV. IL-7 stimulation not only promoted proliferation, cytokines secretion, and STAT-5 phosphorylation in lung-resident CD14⁺ monocytes, but also enhanced CD14⁺ monocytes-induced Th1 and T follicular helper cells activation, which presented as elevated interferon-γ and IL-21 secretion by CD4⁺ T cells. This process required direct cell-to-cell contact, and was dependent on IL-6 secretion. The current data revealed a potential immunopromotive property of IL-7 to lung-resident CD14⁺ monocytes in lung squamous carcinoma.     

Outer membrane protein A of Acinetobacter baumannii induces differentiation of CD4+ T cells toward a Th1 polarizing phenotype through the activation of dendritic cells

Acinetobacter baumannii is an increasing hospital-acquired pathogen that causes a various type of infections, but little is known about the protective immune response to this microorganism. Outer membrane protein A of A. baumannii (AbOmpA) is a major porin protein and plays an important role in pathogenesis. We analyzed interaction between AbOmpA and dendritic cells (DCs) to characterize the role of this protein in promoting innate and adaptive immune responses. AbOmpA functionally activates bone marrow-derived DCs by augmenting expression of the surface markers, CD40, CD54, B7 family (CD80 and CD86) and major histocompatibility complex class I and II. AbOmpA induces production of Th1-promoting interleukin-12 from DCs and augments the syngeneic and allogeneic immunostimulatory capacity of DCs. AbOmpA stimulates production of interferon-γ from T cells in mixed lymphocyte reactions, which suggesting Th1-polarizing capacity. CD4⁺ T cells stimulated by AbOmpA-stimulated DCs show a Th1-polarizing cytokine profile. The expression of surface markers on DCs is mediated by both mitogen-activated protein kinases and NF-κB pathways. Our findings suggest that AbOmpA induces maturation of DCs and drives Th1 polarization, which are important properties for determining the nature of immune response against A. baumannii.     

Paeoniflorin suppresses IL-6/Stat3 pathway via upregulation of Socs3 in dendritic cells in response to 1-chloro-2,4-dinitrobenze

Mounting evidence has suggested that inflammation is associated with IL-6/Stat3 pathway in dendritic cells (DCs) and Th17 cells, which are critical for development of allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proved to be effective in the treatment of inflammatory skin diseases such as ACD. We have previously demonstrated the effect of PF on DCs stimulated with 1-chloro-2,4-dinitrobenze (DNCB) and naïve CD4⁺ CD45RA⁺ T cells for Th17 cell differentiation. However, whether PF down-regulates IL-6/Stat3 in DCs and Th17 cells remains to be explored. In this study, we show clearly that PF markedly decreases IL-6/Stat3 in DCs stimulated with DNCB at both gene and protein levels compared with control DCs in vitro. Meanwhile, PF up-regulates suppressor of cytokine signaling 3 (Socs3). Such decreased expression of IL-6/Stat3 is abolished in DCs that were transfected with Socs3 short interfering RNA (siRNA). When mice CD4⁺ CD45 RA⁺ T cells were co-cultured with PF-treated DCs stimulated with/without DNCB, the gene expression of the Th17 cell markers such as retinoic acid-related orphan nuclear hormone receptor γt (RORγt), IL-17A, and IL-23R decreased, in accordance with the less secretions of IL-17 and IL-23 in vitro and in vivo. Finally, the suppressed Th17 differentiation induced by PF can be abolished by additional recombinant mouse IL-6. Our results suggest that the anti-inflammatory mechanisms introduced by depletion of Socs3 expression or inactivation of the negative regulator such as Socs3 may represent a promising strategy for the prevention of ACD.     

Bone-derived MSCs encapsulated in alginate hydrogel prevent collagen-induced arthritis in mice through the activation of adenosine A2A/2B receptors in tolerogenic dendritic cells

Tolerogenic dendritic cells (tolDCs) facilitate the suppression of autoimmune responses by differentiating regulatory T cells (Treg). The dysfunction of immunotolerance results in the development of autoimmune diseases, such as rheumatoid arthritis (RA). As multipotent progenitor cells, mesenchymal stem cells (MSCs), can regulate dendritic cells (DCs) to restore their immunosuppressive function and prevent disease development. However, the underlying mechanisms of MSCs in regulating DCs still need to be better defined. Simultaneously, the delivery system for MSCs also influences their function. Herein, MSCs are encapsulated in alginate hydrogel to improve cell survival and retention in situ, maximizing efficacy in vivo. The three-dimensional co-culture of encapsulated MSCs with DCs demonstrates that MSCs can inhibit the maturation of DCs and the secretion of pro-inflammatory cytokines. In the collagen-induced arthritis (CIA) mice model, alginate hydrogel encapsulated MSCs induce a significantly higher expression of CD39⁺CD73⁺ on MSCs. These enzymes hydrolyze ATP to adenosine and activate A_2A/2B receptors on immature DCs, further promoting the phenotypic transformation of DCs to tolDCs and regulating naïve T cells to Tregs. Therefore, encapsulated MSCs obviously alleviate the inflammatory response and prevent CIA progression. This finding clarifies the mechanism of MSCs-DCs crosstalk in eliciting the immunosuppression effect and provides insights into hydrogel-promoted stem cell therapy for autoimmune diseases.     

Lactococcus lactis subsp. cremoris FC triggers IFN-γ production from NK and T cells via IL-12 and IL-18

Lactic acid bacteria (LAB) benefit health as probiotics in a strain-dependent way. In this study, we investigated the immunomodulatory effects of Lactococcus lactis subsp. cremoris FC (LcFC) on dendritic cells (DCs), natural killer (NK) cells and T cells. LcFC induced the production of cytokines such as IL-10, IL-12, IL-6 and TNF-α from murine bone marrow DCs (BMDCs) via MyD88-dependent pathway. In comparison with the type strain L. lactis subsp. cremoris ATCC 19257, LcFC induced particularly high production of IL-12 while induction of IL-6 was moderate. Consequently, LcFC triggered IFN-γ production in splenic NK, CD8⁺, and CD4⁺ cells. Most prominent effect of LcFC on IFN-γ production was observed in NK cells, followed by CD8⁺ cells, which was completely inhibited by combination of neutralizing anti-IL-12 and anti-IL-18 mAbs. Moreover, oral administration of LcFC enhanced the production of IFN-γ and IL-10 from splenocytes of treated mice. These findings suggest that this LAB strain is an efficient activator of protective cellular immunity via stimulation of myeloid cells including DCs.     

Circulating T helper 9 cells and increased serum interleukin‐9 levels in patients with knee osteoarthritis

The purpose of this study was to examine the roles of T helper 9 (Th9) cells and the serum interleukin (IL)‐9 level in the pathogenesis of osteoarthritis (OA). The numbers of IL‐9⁺ CD4⁺ CD8^? T cells, interferon (IFN)‐γ+ CD4⁺ CD8^? T cells, IL‐4⁺ CD4⁺ CD8^? T cells, and IL‐17A⁺ CD4⁺ CD8^? T cells in 25 OA patients and 13 healthy controls (HC) were examined by flow cytometry. The serum concentrations of IL‐9, IL‐4, IL‐17A, and IFN‐γ were also determined. The numbers of CD4⁺CD45RO⁺ T cells, Th9 cells, Th1 cells, and Th17 cells in OA patients were significantly higher than those in HCs. Furthermore, serum IL‐9, IL‐17A, and IFN‐γ levels in OA patients were higher than those in HCs. The number of Th9 cells was positively correlated with the number of Th17 cells in OA patients. Furthermore, greater numbers of Th9 cells were positively associated with elevated C‐reactive protein, and both Th9 cells and IL‐9 levels were positively correlated with the Western Ontario and McMaster Universities Osteoarthritis index in OA patients. Th9 cell numbers and IL‐9 levels are correlated with OA patient symptoms and joint functionality and may be a marker of disease activity.     

Generation of αGal-enhanced bifunctional tumor vaccine

Hepatocellular carcinoma (HCC) is a common malignant tumor with poor prognosis and high mortality. In this study, we demonstrated a novel vaccine targeting HCC and tumor neovascular endothelial cells by fusing recombinant MHCC97H cells expressing porcine α-1,3-galactose epitopes (αGal) and endorphin extracellular domains (END) with dendritic cells (DCs) from healthy volunteers. END⁺/Gal⁺-MHCC97H/DC fusion cells induced cytotoxic T lymphocytes (CTLs) and secretion of interferon-gamma (IFN-γ). CTLs targeted cells expressing αGal and END and tumor angiogenesis. The fused cell vaccine can effectively inhibit tumor growth and prolong the survival time of human hepatoma mice, indicating the high clinical potential of this new cell based vaccine.     

The shiitake mushroom-derived immuno-stimulant lentinan protects against murine malaria blood-stage infection by evoking adaptive immune-responses

Lentinan, a (1-3)-beta glucan from Lentinus edodes, is an effective immunostimulatory drug. We tested the effects of lentinan during blood-stage infection by Plasmodium yoelii 17XL (P.y17XL). Pre-treatment of mice with lentinan significantly decreased the parasitemia and increased their survival after infection. Enhanced IL-12, IFN-γ and NO production induced by lentinan in spleen cells of infected mice revealed that the Th1 immune response was stimulated against malaria infection. In vitro and in vivo, lentinan can result in enhanced expression of MHC II, CD80/CD86, and Toll-like receptors (TLR2/TLR4), and increased production of IL-12 in spleen dendritic cells (DCs) co-cultured with parasitized red blood cells (pRBCs). Moreover, both the number of CD4⁺CD25⁺ regulatory T cells (Tregs) and the levels of IL-10 secreted by Tregs were reduced by pre-treatment with lentinan in the spleen of malaria-infected mice. Meanwhile, apoptosis of CD4⁺ T cell in spleens of mice pretreated with lentinan was significantly reduced. In summary, lentinan can induce protective Th1 immune responses to control the proliferation of malaria parasites during the blood-stage of P.y17XL infection by stimulating maturation of DCs to inhibit negative regulation of the Th1 immune response by Tregs. Taken together, our findings suggest that lentinan has prophylactic potential for the treatment of malaria.     

Breg Tfh Tfr细胞在免疫性血小板减少症患者中的表达及意义

目的 探讨调节性B细胞（Breg）、滤泡辅助性T细胞（Tfh）、滤泡调节性T细胞（Tfr）在免疫性血小板减少症（ITP）中的作用和临床意义。方法 选择2017年10月至2019年10月安徽医科大学第一附属医院收治的初次诊断的30例ITP患者为ITP组，同期选择健康对照组25例，应用流式细胞术（FCM）检测外周血Breg、Tfh、Tfr细胞的表达水平并统计分析。结果 ITP组患者外周血CD19⁺B细胞中Breg[（1.93±1.21）%]、IL-10⁺Breg[（28.64±10.31）%]水平低于健康对照组，差异有统计学意义（P<0.05）；外周血CD4⁺T细胞中Tfh细胞比例高于健康对照组[（12.18±5.26）% vs（6.21±1.78）%]，Tfr细胞比例[（1.64±1.01）%]、Tfr/Tfh比值（0.21±0.13）低于健康对照组，差异均有统计学意义（P<0.05）。结论 Breg细胞降低，IL-10分泌减少，Tfr/Tfh比值失衡，在ITP发病过程中可能起到重要的作用。     

Lentiviral-mediated shRNA against RelB induces the generation of tolerogenic dendritic cells

ObjectiveLentiviral-mediated shRNA against RelB was used to produce tolerogenic dendritic cells from murine bone marrow derived dendritic cells (BMDCs).MethodRelB expression in the BMDCs was silenced by lentivirus carrying RelB shRNA. The apoptosis rate and surface markers of DCs were assessed by flow cytometry. IL-12,IL-10,TGF-β1 secreted by DCs and DNA binding capacity of NF-κB subunits in the nucleus were measured by ELISA, independently. MLR was used to analyze the capacity of DCs to inhibit immune response.ResultsRelB expression was significantly inhibited in DCs following lentiviral mediated delivery of RelB specific shRNA. The RelB shRNA-DC produced lower IL-12 and higher IL-10 than mature dendritic cells (mDCs) and silencing control DCs. There was no difference in the apoptosis rate between shRNA RelB-DCs and mDCs. The expression levels of co-stimulatory molecules (CD80, CD86 and CD83) and MHC-II class molecule were lower in the RelB shRNA-DCs than in the mDCs and silencing control DCs. In addition, RelB shRNA also inhibited the RelB DNA binding capacity but had no effect on other NF-κB subunits. The shRNA RelB-DCs can significantly inhibit mixed lymphocyte reaction (MLR) and down-regulate Th1 cytokines and prompt the production of Th2 cytokines.ConclusionOur results indicate RelB shRNA transfection of DCs can induce the immature status, and produce tolerogenic DCs.     

Enhanced dendritic cell maturation by the B-chain of Korean mistletoe lectin (KML-B), a novel TLR4 agonist

Korean mistletoe lectin (KML) is composed of A and B sub-chains. The B-chain binds to cell surfaces, whereas the A-chain hinders translation because it is a RIP (ribosome inactivating protein) inducing apoptosis. Although KML has various biological and immunological activities, its potential use in cancer therapy or as an adjuvant therapy is limited by its toxicity to normal cells. This study was conducted to determine whether the B-chain of KML (KML-B) has immunoadjuvant activity and cytotoxicity activity. To evaluate the immunomodulatory activities of B chain KML, in vitro experiments employing bone marrow-derived dendritic cells (BMDCs) were performed. Dendritic cells (DCs) are a unique group of white blood cells that are able to capture and process antigens for presentation to T cells, which constitute primary immune response. In the present study, KML-B was found to be non-cytotoxic to BMDCs. Furthermore, the expressions of co-stimulatory molecules (CD40, CD80, CD86, and MHC II) and the secretions of cytokines (IL-1β, IL-6, IL-12p70, and TNF-α) were increased in BMDCs by KML-B. In addition, other indicators (antigen-uptake and CCR7 expression) of BMDC maturation were changed by KML-B, and the ability of KML-B to enhance various functions by BMDCs was found to be dependent on TLR4 expression. Moreover, BMDCs matured by KML-B induced naïve CD4⁺ T cell differentiation toward Th1 cells directly and indirectly. These experiments confirm that KML-B exhibits potent immunomodulatory properties and suggest that KML-B be considered a potential dendritic cell-based cancer therapy and immunoadjuvant.     

Paeoniflorin inhibits the maturation and immunostimulatory function of allergen-induced murine dendritic cells

Dendritic cells (DCs) as the front lines of defense play a crucial role in allergic contact dermatitis (ACD). Paeoniflorin (PF) has been clinically proven to be effective in the treatment of inflammatory skin diseases such as ACD. However, the mechanisms underlying the anti-inflammatory effect of PF remain unclear. The aim of this study was to explore the effect of PF on the maturation and immunostimulatory function of DCs in the murine model of ACD in vitro. Murine bone marrow-derived DCs were stimulated with the contact sensitizer 1-chloro-2, 4-dinitrobenze (DNCB) in vitro. Surface antigen expression of DCs (MHC II, CD40, CD80, and CD86), as an indicator of maturation DCs and cytokines (IL-12, IFN-γ, IL-10, and TGF-β) after DNCB stimulation in the absence or presence of PF at different doses, was detected. Then, we detected that PF-treated DCs stimulated T cells in response to DNCB. PF inhibited the up-regulation of MHC II, CD80, CD86, and CD40, decreased IL-12p70 secretion, while increased the production of IL-10 and TGF-β, and had no effect on IFN-γ cytokine production by murine bone marrow-derived DCs in response to DNCB. DCs exposed to PF had diminished capacity to stimulate allogeneic T cell proliferation and to activate IFN-γ-producing CD4⁺ T cells and induced CD4⁺CD25⁺Foxp3⁺ T cells and IL-10-producing T cell expansion from naïve CD4⁺ T cells. These results indicate that PF may be effective in preventing and treating ACD in vitro and other inflammatory responses possibly through inhibiting maturation of DCs and limiting their capacity to stimulate T cell responses.