ReferencesReferencesBackgroundDendritic cells (DCs) can initiate the expansion of regulatory T cells (Tregs), which play an indispensable role in inducing transplantation tolerance. Some studies have investigated the ...ReferencesReferencesBackgroundDendritic cells (DCs) can initiate the expansion of regulatory T cells (Tregs), which play an indispensable role in inducing transplantation tolerance. Some studies have investigated the effect of the immunosuppressant rapamycin (Rapa) on Tregs in vitro. However, the in vivo effect of Rapa combined with immature DCs (iDCs) on Tregs is unknown. This study was undertaken to determine whether allogenic iDCs combined with a short course of Rapa have the ability to selectively expand the CD4+CD25+Foxp3+ Tregs in a rat model.MethodsBrown Norway rats were injected intravenously with 2×106 Lewis iDCs followed by 1 mg/kg per day Rapa intraperitoneally for 7 consecutive days. On day 8, the levels of CD4+CD25+Foxp3+ Treg cells in peripheral blood and spleen cells were analyzed by flow cytometry. IL-2, IL-4, TGF-β1, and IFN-γ levels in serum were assessed by ELISA. The experimental animals were divided into four groups: control, Rapa-treated, iDC-treated, and combination-treated.ResultsCD4+CD25+Foxp3+ Tregs comprised 7%-8%of CD4+ T cells in control rats. Rapa combined with iDCs enhanced this percentage in the peripheral blood and spleen. However, the levels of Tregs did not significantly change after treatment with Rapa or iDCs alone. The levels of CD4+CD25?/sup>Foxp3+ T cells and CD4+ CD25+Foxp3?/sup> T cells in CD4+ T cells did not significantly change in the combined group. The TGF-β1 level in serum from the combined group increased significantly compared with the other groups.ConclusionsA significantly higher percentage of CD4+ CD25+ Foxp3+ Tregs was found in rats treated with allogenic iDCs and a short course of Rapa, along with an increase in the TGF-β1 level in serum. This improved protocol may be a promising therapeutic strategy to increase Tregs, which are beneficial to the induction of peritransplant tolerance.展开更多
Liver transplantation(LT)has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techni...Liver transplantation(LT)has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techniques and perioperative management.However,long-term side-effects of immunosuppressants,like infection,metabolic disorders and malignant tumor are gaining more attention.Immune tolerance is the status in which LT recipients no longer need to take any immunosuppressants,but the liver function and intrahepatic histology maintain normal.The approaches to achieve immune tolerance after transplantation include spontaneous,operational and induced tolerance.The first two means require no specific intervention but withdrawing immunosuppressant gradually during follow-up.No clinical factors or biomarkers so far could accurately predict who are suitable for immunosuppressant withdraw after transplantation.With the understanding to the underlying mechanisms of immune tolerance,many strategies have been developed to induce tolerance in LT recipients.Cellular strategy is one of the most promising methods for immune tolerance induction,including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory immune cells.The safety and efficacy of various cell products have been evaluated by prospective preclinical and clinical trials,while obstacles still exist before translating into clinical practice.Here,we will summarize the latest perspectives and concerns on the clinical application of cellular strategies in LT recipients.展开更多
Objective:To investigate the effects of soluble factors secreted by acute myeloid leukemia(AML) cells on the phenotypical and functional properties of DCs derived from normal mononuclear cells. Methods:Mononuclear cel...Objective:To investigate the effects of soluble factors secreted by acute myeloid leukemia(AML) cells on the phenotypical and functional properties of DCs derived from normal mononuclear cells. Methods:Mononuclear cells were cul-tured with interleukin-4(IL-4) and granulocyte-macrophage colony-stimulating factor(GM-CSF),in the presence or absence of 24 h culture supernatants from fresh primary AML cells,to generate immature DCs. The maturation of DCs was induced by cytokines IL-1beta,IL-6,tumor necrosis factor-alpha(TNF-alpha),and prostaglandin-2(PGE-2). The phenotypic alterations of DCs and DCs-primed CD4+ T cells were evaluated using flow cytometry. Precursor frequency(PF) was calculated to monitor the allostimulatory effects of DCs on CD4+ and CD8+ T cells. Results:AML cell supernatant-treated DCs showed significantly lower expression of co-stimulatory molecules CD80 and CD86,and reduced response to cytokines IL-1beta,IL-6,TNF-alpha,and PGE-2. The allostimulatory effects of AML cell supernatant-treated DCs on CD4+ and CD8+ T cells were significantly lower than those of normal mature DCs [PF:(1.8 ± 0.5)% vs.(5.2 ± 1.6)% for CD4+ T cells,(2.1 ± 0.6)% vs.(6.5 ± 2.0)% for CD8+ T cells,P < 0.01]. These AML supernatant-induced DCs could also induce allogeneic CD4+ T cells to differentiate into CD4+CD25high T cells,which had immunophenotyping characteristics of regulatory T cells,i.e. they expressed Foxp3 but not active maker CD69. Conclusion:This study demonstrates that soluble factors secreted by AML cells can inhibit development and functions of DCs. In addition,AML supernatant-induced DCs can induce the generation of CD4+CD25high T cells from CD4+ T cells,which may be a mechanism of increased prevalence of CD4+CD25high regulatory T cells and immune dysfunction in AML patients.展开更多
AIM: To explore the probable pathway by which curcumin(Cur) regulates the function of Treg cells by observing the expression of costimulatory molecules of dendritic cells(DCs).METHODS: Experimental colitis was induced...AIM: To explore the probable pathway by which curcumin(Cur) regulates the function of Treg cells by observing the expression of costimulatory molecules of dendritic cells(DCs).METHODS: Experimental colitis was induced by administering 2, 4, 6-trinitrobenzene sulfonic acid(TNBS)/ethanol solution. Forty male C57BL/6 mice were randomly divided into four groups: normal, TNBS + Cur, TNBS + mesalazine(Mes) and TNBS groups. The mice in the TNBS + Cur and TNBS +Mes groups were treated with Cur and Mes, respectively, while those in the TNBS group were treated with physiological saline for 7 d. After treatment, the curative effect of Cur was evaluated by colonic weight, colonic length, weight index of the colon, and histological observation and score. The levels of CD4+CD25+Foxp3+ T cells(Treg cells) and costimulatory molecules of DCs were measured by flow cytometry. Also, related cytokines were analyzed by enzyme-linked immunosorbent assay. RESULTS: Cur alleviated inflammatory injury of the colonic mucosa, decreased colonic weigh and histological score, and restored colonic length. The number of Treg cells was increased, while the secretion of TNF-α, IL-2, IL-6, IL-12 p40, IL-17 and IL-21 and the expression of costimulatory molecules(CD205, CD54 [ICAM-1], TLR4, CD252[OX40 L], CD256 [RANK] and CD254 [RANK L]) of DCs were notably inhibited in colitis mice treated with Cur.CONCLUSION: Cur potentially modulates activation of DCs to enhance the suppressive functions of Treg cells and promote the recovery of damaged colonic mucosa in inflammatory bowel disease.展开更多
·AIM: To study the role of immature dendritic cells (imDCs) on immune tolerance in rat penetrating keratoplasty (PKP) in high -risk eyes and to investigate the mechanism of immune hyporesponsiveness induced by do...·AIM: To study the role of immature dendritic cells (imDCs) on immune tolerance in rat penetrating keratoplasty (PKP) in high -risk eyes and to investigate the mechanism of immune hyporesponsiveness induced by donor-derived imDCs. ·METHODS: Seventy-five SD rats (recipient) and 39 Wistar rats (donor) were randomly divided into 3 groups: control, imDC and mature dendritic cell (mDC) group respectively. Using a model of orthotopic corneal transplantation in which allografts were placed in neovascularized high -risk eyes of recipient rat. Corneal neovascularization was induced by alkaline burn in the central cornea of recipient rat. Recipients in imDC group or mDC group were injected donor bone marrow-derived imDCs or mDCs of 1 ×10 6 respectively 1 week before corneal transplantation tail vein. Control rat received the same volume of PBS. In each group, 16 recipients were kept for determination of survival time and other 9 recipients were executed on day 3, 7 and 14 after transplantation. Cornea was harvested for hematoxylin eosin staining and acute rejection evaluation, Western blot was used to detect the expression level of Foxp3. ·RESULTS: The mean survival time of imDC group was significantly longer than that of control and mDC groups (all 【0.05). The expression level of Foxp3 on CD4 + CD25 + T cells of imDC group (2.24 ±0.18) was significantly higher than that in the control (1.68 ±0.09) and mDC groups (1.46±0.13) (all 【0.05).·CONCLUSION: Donor -derived imDC is an effective treatment in inducing immune hyporesponsiveness in rat PKP. The mechanism of immune tolerance induced by imDC might be inhibit T lymphocytes responsiveness by regulatory T cells. ·展开更多
The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect ag...The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect against infections,while avoiding the development of destructive inflammatory responses to the microbiota.Several models have been proposed to explain how the immune system discriminates between,and appropriately responds to,commensal and pathogenic microorganisms.Dendritic cells(DCs)and regulatory T cells(Treg)are instrumental in maintaining immune homeostasis and tolerance in the gut.DCs are virtually omnipresent and are remarkably plastic,having the ability to adapt to the influences of the microenvironment.Different DC populations with partially overlapping phenotypic and functional properties have been described in different anatomical locations.DCs in the draining mesenteric lymph nodes,in the intestinal lamina propria and in Peyer's patches partake both in the control of intestinal inflammation and in the maintenance of gut tolerance.In this respect,gutresident DCs and macrophages exert tolerogenic functions as they regularly encounter and sense commensal bacteria.In contrast,migrating DC subsets that are recruited to the gut as a result of pathogenic insults initiate immune responses.Importantly,tolerogenic DCs act by promoting the differentiation and expansion of Treg cells that efficiently modulate gut inflammation,as shown both in preclinical models of colitis and in patients with inflammatory bowel disease(IBD).This article reviews the phenotypic and functional features of gut DC subsets and discusses the current evidence underpinning the DC contribution to the pathogenesis of the major clinical subtypes of human IBD.It also addresses the potential clinical benefit derived from DC targeting either in vivo or in vitro.展开更多
Tumor immunity proceeds through multiple processes, which consist of antigen presentation by antigen presenting cells(APCs) to educate effector cells and destruction by the effector cytotoxic cells. However, tumor imm...Tumor immunity proceeds through multiple processes, which consist of antigen presentation by antigen presenting cells(APCs) to educate effector cells and destruction by the effector cytotoxic cells. However, tumor immunity is frequently repressed at tumor sites. Malignantly transformed cells rarely survive the attack by the immune system, but cells that do survive change their phenotypes to reduce their immunogenicity. The resultant cells evade the attack by the immune system and form clinically discernible tumors. Tumor microenvironments simultaneously contain a wide variety of immune suppressive molecules and cells to dampen tumor immunity. Moreover, the liver microenvironment exhibits immune tolerance to reduce aberrant immune responses to massively-exposed antigens via the portal vein, and immune dysfunction is frequently associated with liver cirrhosis, which is widespread in hepatocellular carcinoma(HCC) patients. Immune therapy aims to reduce tumor burden, but it is also expected to prevent non-cancerous liver lesions from progressing to HCC, because HCC develops or recurs from noncancerous liver lesions with chronic inflammatory states and/or cirrhosis and these lesions cannot be cured and/or eradicated by local and/or systemic therapies. Nevertheless, cancer immune therapy should augment specific tumor immunity by using two distinct measures: enhancing the effector cell functions such as antigen presentation capacity of APCs and tumor cell killing capacity of cytotoxic cells, and reactivating the immune system in immune-suppressive tumor microenvironments. Here, we will summarize the current status and discuss the future perspective on immune therapy for HCC.展开更多
An important percentage of colorectal cancer(CRC) patients will develop metastasis,mainly in the liver,even after a successful curative resection.This leads to a very high mortality rate if metastasis is not detected ...An important percentage of colorectal cancer(CRC) patients will develop metastasis,mainly in the liver,even after a successful curative resection.This leads to a very high mortality rate if metastasis is not detected early on.Disseminated cancer cells develop from metastatic stem cells(Met SCs).Recent knowledge has accumulated about these cells particularly in CRC,so they may now be tracked from the removed primary tumour.This approach could be especially important in prognosis of metastasis because it is becoming clear that metastasis does not particularly rely on testable driver mutations.Among the many traits supporting an epigenetic amplification of cell survival and self-renewal mechanisms of Met SCs,the role of many immune cell populations present in tumour tissues is becoming clear.The amount of tumour-infiltrating lymphocytes(T,B and natural killer cells),dendritic cells and some regulatory populations have already shown prognostic value or to be correlated with disease-free survival time,mainly in immunohistochemistry studies of unique cell populations.Parallel analyses of these immune cell populations together with Met SCs in the primary tumour of patients,with later follow-up data of the patients,will define the usefulness of specific combinations of both immune and Met SCs cell populations.It is expected that these combinations,together to different biomarkers in the form of an immune score,may predict future tumour recurrences,metastases and/or mortality in CRC.It will also support the future design of improved immunotherapeutic approaches against metastasis.展开更多
SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signa...SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signal for the regulation of dendritic cell （DC） maturation. However, it remains unclear whether DCs transduced with SOCS1 exhibit characteristics of regulatory DCs and induce allogeneic T-cell hyporesponsiveness. In this study, we constructed adenovirai vector coding SOCS1 （Ad-SOCS1） that can efficiently increase SOCS1 gene expression in bone marrow-derived dendritic cells. DCs transduced with Ad-SOCS1 （DC-SOCS1） expressed low levels of costimulatory and MHC molecules, were resistant to maturation and activation stimulation, induced allogeneic T-cell hyporesponsiveness, and promoted the generation of regulatory-like T cells in vitro. DC-SOCS1 pretreatment significantly prolonged the survival of ailografts and led to a substantial increase in the generation of regulatory T cells. Our data suggest that SOCS1 inhibits DC maturation and induces regulatory DC generation, therefore possessing therapeutic potential to prevent rejection in organ transplantation.展开更多
The importance of secretory IgA in controlling the microbiota is well known, yet how the antibody affects the perception of the commensals by the local immune system is still poorly defined. We have previously shown t...The importance of secretory IgA in controlling the microbiota is well known, yet how the antibody affects the perception of the commensals by the local immune system is still poorly defined. We have previously shown that the transport of secretory IgA in complex with bacteria across intestinal micmfold cells results in an association with dendritic cells in Peyer＇s patches. However, the consequences of such an interaction on dendritic cell conditioning have not been elucidated. In this study, we analyzed the impact of the commensal Lactobacillus rhamnosus, alone or associated with secretory IgA, on the responsiveness of dendritic cells freshly recovered from mouse Peyer＇s patches, mesenteric lymph nodes, and spleen. Lactobacillus rhamnosus-conditioned mucosal dendritic cells are characterized by increased expression of Toll-like receptor regulatory proteins lincluding single immunoglobulin interleukin-1 receptor-related molecule, suppressor of cytokine signaling 1, and Toll-interacting moleculel and retinaldehyde dehydrogenase 2, low surface expression of co-stimulatory markers, high anti- versus pro-inflammatory cytokine production ratios, and induction of T regulatory cells with suppressive function. Association with secretory IgA enhanced the anti-inflammatory/regulatory Lactobacillus rhamnosus-induced conditioning of mucosal dendritic cells, particularly in Peyer＇s patches. At the systemic level, activation of splenic dendritic cells exposed to Lactobacillus rhamnosus was partially dampened upon association with secretory IgA. These data suggest that secretory IgA, through coating of commensal bacteria, contributes to the conditioning of mucosal dendritic cells toward tolerogenic profiles essential for the maintenance of intestinal homeostasis.展开更多
cell transfer has been found to be able to facilitate engraftment of allograft. However, the underlying mechanisms remain to be fully understood. Here we demonstrate that intravenous administration of donor apoptotic ...cell transfer has been found to be able to facilitate engraftment of allograft. However, the underlying mechanisms remain to be fully understood. Here we demonstrate that intravenous administration of donor apoptotic splenocytes can promote pancreatic islet engraftment by inducing generation of tolerogenic dendritic cells （ToI-DCs） and expansion of CD4＋Foxp3＋ regulatory T cells （Tregs）. In vivo clearance of either dendritic cells （DCs） or Tregs prevented the induction of immune tolerance by apoptotic cell administration. Transient elimination of Tregs using anti-CD25, monoclonal antibody （mAb） abrogated the generation of ToI-DCs after administration of apoptotic splenocytes. Reciprocally, depletion of DCs within CD1 lc-DTR mice using diphtheria toxin （DT） prevented the generation of Tregs in the recipients with administration of apoptotic splenocytes. Induction of Tregs by ToI-DCs required direct cell contact between the two cell types, and programmed death 1 ligand （PD-L1） played important role in the Tregs expansion. Apoptotic cell administration failed to induce ToI-DCs in IL-lO-deficient and Smad3-deficient mice, suggesting that IL-10 and transforming growth factor-β （TGF-β） are needed to maintain DCs in the tolerogenic state. Therefore, we demonstrate that ToI-DCs promote the expansion of Tregs via PD-L1 on their surface and reciprocally Tregs facilitate ToI-DCs to maintain transplantation tolerance induced by apoptotic cells via secreting IL-IO and TGF-β.展开更多
Regulatory B cells(Bregs)suppress and reduce autoimmune pathology.However,given the variety of Breg subsets,the role of Bregs in the pathogenesis of type 1 diabetes is still unclear.Here,we dissect this fundamental me...Regulatory B cells(Bregs)suppress and reduce autoimmune pathology.However,given the variety of Breg subsets,the role of Bregs in the pathogenesis of type 1 diabetes is still unclear.Here,we dissect this fundamental mechanism.We show that natural protection from type 1 diabetes in nonobese diabetic(NOD)mice is associated with increased numbers of IL-10-producing B cells,while development of type 1 diabetes in NOD mice occurs in animals with compromised IL-10 production by B cells.However,B cells from diabetic mice regain IL-10 function if activated by the innate immune receptor TLR4 and can suppress insulin-specific CD8 T cells in a dendritic cell(DC)-dependent,IL-10-mediated fashion.Suppression of CD8 T cells is reliant on B-cell contact with DCs.This cell contact results in deactivation of DCs,inducing a tolerogenic state,which in turn can regulate pathogenic CD8 T cells.Our findings emphasize the importance of DC–Breg interactions during the development of type 1 diabetes.展开更多
Functional Tregs play a key role in tumor development and progression,representing a major barrier to anticancer immunity.The mechanisms by which Tregs are generated in cancer and the influence of the tumor microenvir...Functional Tregs play a key role in tumor development and progression,representing a major barrier to anticancer immunity.The mechanisms by which Tregs are generated in cancer and the influence of the tumor microenvironment on these processes remain incompletely understood.Herein,by using NMR,chemoenzymatic structural assays and a plethora of in vitro and in vivo functional analyses,we demonstrate that the tumoral carbohydrate A10(Ca10),a cell-surface carbohydrate derived from Ehrlich’s tumor(ET)cells,is a heparan sulfate-related proteoglycan that enhances glycolysis and promotes the development of tolerogenic features in human DCs.Ca10-stimulated human DCs generate highly suppressive Tregs by mechanisms partially dependent on metabolic reprogramming,PD-L1,IL-10,and IDO.Ca10 also reprograms the differentiation of human monocytes into DCs with tolerogenic features.In solid ET-bearing mice,we found positive correlations between Ca10 serum levels,tumor size and splenic Treg numbers.Administration of isolated Ca10 also increases the proportion of splenic Tregs in tumor-free mice.Remarkably,we provide evidence supporting the presence of a circulating human Ca10 counterpart(Ca10H)and show,for the first time,that serum levels of Ca10H are increased in patients suffering from different cancer types compared to healthy individuals.Of note,these levels are higher in prostate cancer patients with bone metastases than in prostate cancer patients without metastases.Collectively,we reveal novel molecular mechanisms by which heparan sulfate-related structures associated with tumor cells promote the generation of functional Tregs in cancer.The discovery of this novel structural-functional relationship may open new avenues of research with important clinical implications in cancer treatment.展开更多
基金supported by grants from the Major State Basic Research Development Program of China(973 Program) (2009CB522404)the National Natural Science Foundation of China (30801112,30972915,and 81000190)the National Twelfth Five-Year Science and Technology Plan Major Projects of China (2012ZX10002-017)
文摘ReferencesReferencesBackgroundDendritic cells (DCs) can initiate the expansion of regulatory T cells (Tregs), which play an indispensable role in inducing transplantation tolerance. Some studies have investigated the effect of the immunosuppressant rapamycin (Rapa) on Tregs in vitro. However, the in vivo effect of Rapa combined with immature DCs (iDCs) on Tregs is unknown. This study was undertaken to determine whether allogenic iDCs combined with a short course of Rapa have the ability to selectively expand the CD4+CD25+Foxp3+ Tregs in a rat model.MethodsBrown Norway rats were injected intravenously with 2×106 Lewis iDCs followed by 1 mg/kg per day Rapa intraperitoneally for 7 consecutive days. On day 8, the levels of CD4+CD25+Foxp3+ Treg cells in peripheral blood and spleen cells were analyzed by flow cytometry. IL-2, IL-4, TGF-β1, and IFN-γ levels in serum were assessed by ELISA. The experimental animals were divided into four groups: control, Rapa-treated, iDC-treated, and combination-treated.ResultsCD4+CD25+Foxp3+ Tregs comprised 7%-8%of CD4+ T cells in control rats. Rapa combined with iDCs enhanced this percentage in the peripheral blood and spleen. However, the levels of Tregs did not significantly change after treatment with Rapa or iDCs alone. The levels of CD4+CD25?/sup>Foxp3+ T cells and CD4+ CD25+Foxp3?/sup> T cells in CD4+ T cells did not significantly change in the combined group. The TGF-β1 level in serum from the combined group increased significantly compared with the other groups.ConclusionsA significantly higher percentage of CD4+ CD25+ Foxp3+ Tregs was found in rats treated with allogenic iDCs and a short course of Rapa, along with an increase in the TGF-β1 level in serum. This improved protocol may be a promising therapeutic strategy to increase Tregs, which are beneficial to the induction of peritransplant tolerance.
基金Supported by the National Natural Science Foundation of China,No.82000586 and No.82241221and Shanghai Immune Therapy Institute.
文摘Liver transplantation(LT)has become the most efficient treatment for pediatric and adult end-stage liver disease and the survival time after transplantation is becoming longer due to the development of surgical techniques and perioperative management.However,long-term side-effects of immunosuppressants,like infection,metabolic disorders and malignant tumor are gaining more attention.Immune tolerance is the status in which LT recipients no longer need to take any immunosuppressants,but the liver function and intrahepatic histology maintain normal.The approaches to achieve immune tolerance after transplantation include spontaneous,operational and induced tolerance.The first two means require no specific intervention but withdrawing immunosuppressant gradually during follow-up.No clinical factors or biomarkers so far could accurately predict who are suitable for immunosuppressant withdraw after transplantation.With the understanding to the underlying mechanisms of immune tolerance,many strategies have been developed to induce tolerance in LT recipients.Cellular strategy is one of the most promising methods for immune tolerance induction,including chimerism induced by hematopoietic stem cells and adoptive transfer of regulatory immune cells.The safety and efficacy of various cell products have been evaluated by prospective preclinical and clinical trials,while obstacles still exist before translating into clinical practice.Here,we will summarize the latest perspectives and concerns on the clinical application of cellular strategies in LT recipients.
基金grants from the National Outstanding Young Investigator Program (30225038)Anhui Provincial Natural Science Foundation (070413094)+1 种基金Scientific Research Fund of Anhui Provincial Education Department (2006KJ072C)Science and Technological Fund of Anhui Province for Outstanding Youth.
文摘Objective:To investigate the effects of soluble factors secreted by acute myeloid leukemia(AML) cells on the phenotypical and functional properties of DCs derived from normal mononuclear cells. Methods:Mononuclear cells were cul-tured with interleukin-4(IL-4) and granulocyte-macrophage colony-stimulating factor(GM-CSF),in the presence or absence of 24 h culture supernatants from fresh primary AML cells,to generate immature DCs. The maturation of DCs was induced by cytokines IL-1beta,IL-6,tumor necrosis factor-alpha(TNF-alpha),and prostaglandin-2(PGE-2). The phenotypic alterations of DCs and DCs-primed CD4+ T cells were evaluated using flow cytometry. Precursor frequency(PF) was calculated to monitor the allostimulatory effects of DCs on CD4+ and CD8+ T cells. Results:AML cell supernatant-treated DCs showed significantly lower expression of co-stimulatory molecules CD80 and CD86,and reduced response to cytokines IL-1beta,IL-6,TNF-alpha,and PGE-2. The allostimulatory effects of AML cell supernatant-treated DCs on CD4+ and CD8+ T cells were significantly lower than those of normal mature DCs [PF:(1.8 ± 0.5)% vs.(5.2 ± 1.6)% for CD4+ T cells,(2.1 ± 0.6)% vs.(6.5 ± 2.0)% for CD8+ T cells,P < 0.01]. These AML supernatant-induced DCs could also induce allogeneic CD4+ T cells to differentiate into CD4+CD25high T cells,which had immunophenotyping characteristics of regulatory T cells,i.e. they expressed Foxp3 but not active maker CD69. Conclusion:This study demonstrates that soluble factors secreted by AML cells can inhibit development and functions of DCs. In addition,AML supernatant-induced DCs can induce the generation of CD4+CD25high T cells from CD4+ T cells,which may be a mechanism of increased prevalence of CD4+CD25high regulatory T cells and immune dysfunction in AML patients.
基金Supported by project of National Natural Science Foundation of ChinaNo.81260595 and No.81460679+3 种基金Chinese Scholarship Council and Jiangxi province as visiting scholarNo.201408360106 and No.201408360110project of Jiangxi University of Traditional Chinese MedicineNo.JZYC15S13
文摘AIM: To explore the probable pathway by which curcumin(Cur) regulates the function of Treg cells by observing the expression of costimulatory molecules of dendritic cells(DCs).METHODS: Experimental colitis was induced by administering 2, 4, 6-trinitrobenzene sulfonic acid(TNBS)/ethanol solution. Forty male C57BL/6 mice were randomly divided into four groups: normal, TNBS + Cur, TNBS + mesalazine(Mes) and TNBS groups. The mice in the TNBS + Cur and TNBS +Mes groups were treated with Cur and Mes, respectively, while those in the TNBS group were treated with physiological saline for 7 d. After treatment, the curative effect of Cur was evaluated by colonic weight, colonic length, weight index of the colon, and histological observation and score. The levels of CD4+CD25+Foxp3+ T cells(Treg cells) and costimulatory molecules of DCs were measured by flow cytometry. Also, related cytokines were analyzed by enzyme-linked immunosorbent assay. RESULTS: Cur alleviated inflammatory injury of the colonic mucosa, decreased colonic weigh and histological score, and restored colonic length. The number of Treg cells was increased, while the secretion of TNF-α, IL-2, IL-6, IL-12 p40, IL-17 and IL-21 and the expression of costimulatory molecules(CD205, CD54 [ICAM-1], TLR4, CD252[OX40 L], CD256 [RANK] and CD254 [RANK L]) of DCs were notably inhibited in colitis mice treated with Cur.CONCLUSION: Cur potentially modulates activation of DCs to enhance the suppressive functions of Treg cells and promote the recovery of damaged colonic mucosa in inflammatory bowel disease.
基金Military Medical Research Projects Fund of China (No. CLZ11JA25)
文摘·AIM: To study the role of immature dendritic cells (imDCs) on immune tolerance in rat penetrating keratoplasty (PKP) in high -risk eyes and to investigate the mechanism of immune hyporesponsiveness induced by donor-derived imDCs. ·METHODS: Seventy-five SD rats (recipient) and 39 Wistar rats (donor) were randomly divided into 3 groups: control, imDC and mature dendritic cell (mDC) group respectively. Using a model of orthotopic corneal transplantation in which allografts were placed in neovascularized high -risk eyes of recipient rat. Corneal neovascularization was induced by alkaline burn in the central cornea of recipient rat. Recipients in imDC group or mDC group were injected donor bone marrow-derived imDCs or mDCs of 1 ×10 6 respectively 1 week before corneal transplantation tail vein. Control rat received the same volume of PBS. In each group, 16 recipients were kept for determination of survival time and other 9 recipients were executed on day 3, 7 and 14 after transplantation. Cornea was harvested for hematoxylin eosin staining and acute rejection evaluation, Western blot was used to detect the expression level of Foxp3. ·RESULTS: The mean survival time of imDC group was significantly longer than that of control and mDC groups (all 【0.05). The expression level of Foxp3 on CD4 + CD25 + T cells of imDC group (2.24 ±0.18) was significantly higher than that in the control (1.68 ±0.09) and mDC groups (1.46±0.13) (all 【0.05).·CONCLUSION: Donor -derived imDC is an effective treatment in inducing immune hyporesponsiveness in rat PKP. The mechanism of immune tolerance induced by imDC might be inhibit T lymphocytes responsiveness by regulatory T cells. ·
基金Supported by The "Stem Cell Project",Fondazione Roma,Italy and by the Associazione Italiana per la Ricerca sul Cancro,Milan,Italy(AIRC,Grant No.8556)
文摘The gastrointestinal tract harbors a large number and diverse array of commensal bacteria and is an important entry site for pathogens.For these reasons,the intestinal immune system is uniquely dedicated to protect against infections,while avoiding the development of destructive inflammatory responses to the microbiota.Several models have been proposed to explain how the immune system discriminates between,and appropriately responds to,commensal and pathogenic microorganisms.Dendritic cells(DCs)and regulatory T cells(Treg)are instrumental in maintaining immune homeostasis and tolerance in the gut.DCs are virtually omnipresent and are remarkably plastic,having the ability to adapt to the influences of the microenvironment.Different DC populations with partially overlapping phenotypic and functional properties have been described in different anatomical locations.DCs in the draining mesenteric lymph nodes,in the intestinal lamina propria and in Peyer's patches partake both in the control of intestinal inflammation and in the maintenance of gut tolerance.In this respect,gutresident DCs and macrophages exert tolerogenic functions as they regularly encounter and sense commensal bacteria.In contrast,migrating DC subsets that are recruited to the gut as a result of pathogenic insults initiate immune responses.Importantly,tolerogenic DCs act by promoting the differentiation and expansion of Treg cells that efficiently modulate gut inflammation,as shown both in preclinical models of colitis and in patients with inflammatory bowel disease(IBD).This article reviews the phenotypic and functional features of gut DC subsets and discusses the current evidence underpinning the DC contribution to the pathogenesis of the major clinical subtypes of human IBD.It also addresses the potential clinical benefit derived from DC targeting either in vivo or in vitro.
基金Supported by(in part)Research Programs on the Innovative Development and Application for New Drugs for Hepatitis B(No.17fk0310116h0001) from the Japan Agency for Medical Research and Development(AMED)Extramural Collaborative Research Grant of Cancer Research Institute,Kanazawa University
文摘Tumor immunity proceeds through multiple processes, which consist of antigen presentation by antigen presenting cells(APCs) to educate effector cells and destruction by the effector cytotoxic cells. However, tumor immunity is frequently repressed at tumor sites. Malignantly transformed cells rarely survive the attack by the immune system, but cells that do survive change their phenotypes to reduce their immunogenicity. The resultant cells evade the attack by the immune system and form clinically discernible tumors. Tumor microenvironments simultaneously contain a wide variety of immune suppressive molecules and cells to dampen tumor immunity. Moreover, the liver microenvironment exhibits immune tolerance to reduce aberrant immune responses to massively-exposed antigens via the portal vein, and immune dysfunction is frequently associated with liver cirrhosis, which is widespread in hepatocellular carcinoma(HCC) patients. Immune therapy aims to reduce tumor burden, but it is also expected to prevent non-cancerous liver lesions from progressing to HCC, because HCC develops or recurs from noncancerous liver lesions with chronic inflammatory states and/or cirrhosis and these lesions cannot be cured and/or eradicated by local and/or systemic therapies. Nevertheless, cancer immune therapy should augment specific tumor immunity by using two distinct measures: enhancing the effector cell functions such as antigen presentation capacity of APCs and tumor cell killing capacity of cytotoxic cells, and reactivating the immune system in immune-suppressive tumor microenvironments. Here, we will summarize the current status and discuss the future perspective on immune therapy for HCC.
文摘An important percentage of colorectal cancer(CRC) patients will develop metastasis,mainly in the liver,even after a successful curative resection.This leads to a very high mortality rate if metastasis is not detected early on.Disseminated cancer cells develop from metastatic stem cells(Met SCs).Recent knowledge has accumulated about these cells particularly in CRC,so they may now be tracked from the removed primary tumour.This approach could be especially important in prognosis of metastasis because it is becoming clear that metastasis does not particularly rely on testable driver mutations.Among the many traits supporting an epigenetic amplification of cell survival and self-renewal mechanisms of Met SCs,the role of many immune cell populations present in tumour tissues is becoming clear.The amount of tumour-infiltrating lymphocytes(T,B and natural killer cells),dendritic cells and some regulatory populations have already shown prognostic value or to be correlated with disease-free survival time,mainly in immunohistochemistry studies of unique cell populations.Parallel analyses of these immune cell populations together with Met SCs in the primary tumour of patients,with later follow-up data of the patients,will define the usefulness of specific combinations of both immune and Met SCs cell populations.It is expected that these combinations,together to different biomarkers in the form of an immune score,may predict future tumour recurrences,metastases and/or mortality in CRC.It will also support the future design of improved immunotherapeutic approaches against metastasis.
基金supported by grants from the National Key Basic Research Program of China (2009CB522402)the National Natural Science Foundation of China (30571756, 30772056, 30772046, U0832009).
文摘SOCS1 is a key regulator of cytokine signaling and is important for maintaining balance in the immune system. It is thought to participate in negative feedback loops in cytokine signaling and may be an important signal for the regulation of dendritic cell （DC） maturation. However, it remains unclear whether DCs transduced with SOCS1 exhibit characteristics of regulatory DCs and induce allogeneic T-cell hyporesponsiveness. In this study, we constructed adenovirai vector coding SOCS1 （Ad-SOCS1） that can efficiently increase SOCS1 gene expression in bone marrow-derived dendritic cells. DCs transduced with Ad-SOCS1 （DC-SOCS1） expressed low levels of costimulatory and MHC molecules, were resistant to maturation and activation stimulation, induced allogeneic T-cell hyporesponsiveness, and promoted the generation of regulatory-like T cells in vitro. DC-SOCS1 pretreatment significantly prolonged the survival of ailografts and led to a substantial increase in the generation of regulatory T cells. Our data suggest that SOCS1 inhibits DC maturation and induces regulatory DC generation, therefore possessing therapeutic potential to prevent rejection in organ transplantation.
文摘The importance of secretory IgA in controlling the microbiota is well known, yet how the antibody affects the perception of the commensals by the local immune system is still poorly defined. We have previously shown that the transport of secretory IgA in complex with bacteria across intestinal micmfold cells results in an association with dendritic cells in Peyer＇s patches. However, the consequences of such an interaction on dendritic cell conditioning have not been elucidated. In this study, we analyzed the impact of the commensal Lactobacillus rhamnosus, alone or associated with secretory IgA, on the responsiveness of dendritic cells freshly recovered from mouse Peyer＇s patches, mesenteric lymph nodes, and spleen. Lactobacillus rhamnosus-conditioned mucosal dendritic cells are characterized by increased expression of Toll-like receptor regulatory proteins lincluding single immunoglobulin interleukin-1 receptor-related molecule, suppressor of cytokine signaling 1, and Toll-interacting moleculel and retinaldehyde dehydrogenase 2, low surface expression of co-stimulatory markers, high anti- versus pro-inflammatory cytokine production ratios, and induction of T regulatory cells with suppressive function. Association with secretory IgA enhanced the anti-inflammatory/regulatory Lactobacillus rhamnosus-induced conditioning of mucosal dendritic cells, particularly in Peyer＇s patches. At the systemic level, activation of splenic dendritic cells exposed to Lactobacillus rhamnosus was partially dampened upon association with secretory IgA. These data suggest that secretory IgA, through coating of commensal bacteria, contributes to the conditioning of mucosal dendritic cells toward tolerogenic profiles essential for the maintenance of intestinal homeostasis.
文摘cell transfer has been found to be able to facilitate engraftment of allograft. However, the underlying mechanisms remain to be fully understood. Here we demonstrate that intravenous administration of donor apoptotic splenocytes can promote pancreatic islet engraftment by inducing generation of tolerogenic dendritic cells （ToI-DCs） and expansion of CD4＋Foxp3＋ regulatory T cells （Tregs）. In vivo clearance of either dendritic cells （DCs） or Tregs prevented the induction of immune tolerance by apoptotic cell administration. Transient elimination of Tregs using anti-CD25, monoclonal antibody （mAb） abrogated the generation of ToI-DCs after administration of apoptotic splenocytes. Reciprocally, depletion of DCs within CD1 lc-DTR mice using diphtheria toxin （DT） prevented the generation of Tregs in the recipients with administration of apoptotic splenocytes. Induction of Tregs by ToI-DCs required direct cell contact between the two cell types, and programmed death 1 ligand （PD-L1） played important role in the Tregs expansion. Apoptotic cell administration failed to induce ToI-DCs in IL-lO-deficient and Smad3-deficient mice, suggesting that IL-10 and transforming growth factor-β （TGF-β） are needed to maintain DCs in the tolerogenic state. Therefore, we demonstrate that ToI-DCs promote the expansion of Tregs via PD-L1 on their surface and reciprocally Tregs facilitate ToI-DCs to maintain transplantation tolerance induced by apoptotic cells via secreting IL-IO and TGF-β.
基金This work was funded by the Medical Research Council(UK)(MR/K021141/1 to FSW)LCDR was funded by a studentship from Cnpq(Conselho Nacional de Pesquisa,Brazil,grant#245609/2012-1).
文摘Regulatory B cells(Bregs)suppress and reduce autoimmune pathology.However,given the variety of Breg subsets,the role of Bregs in the pathogenesis of type 1 diabetes is still unclear.Here,we dissect this fundamental mechanism.We show that natural protection from type 1 diabetes in nonobese diabetic(NOD)mice is associated with increased numbers of IL-10-producing B cells,while development of type 1 diabetes in NOD mice occurs in animals with compromised IL-10 production by B cells.However,B cells from diabetic mice regain IL-10 function if activated by the innate immune receptor TLR4 and can suppress insulin-specific CD8 T cells in a dendritic cell(DC)-dependent,IL-10-mediated fashion.Suppression of CD8 T cells is reliant on B-cell contact with DCs.This cell contact results in deactivation of DCs,inducing a tolerogenic state,which in turn can regulate pathogenic CD8 T cells.Our findings emphasize the importance of DC–Breg interactions during the development of type 1 diabetes.
基金upported by grants FEI 16_60 from Art.834154605(138/2012)(24/2013),SAF-2017-84978-R from MINECO(Spain)and PID2020-114396RB-I00 from Ministerio de Ciencia e Innovación(Spain)to OP and PID2021-123781OB-C22 to FJC funded by MCIN/AEI/10.13039/501100011033(Spain)and RTC-2015-3805-1 from MINECO to Inmunotek SL.LM-C and AA were recipients of FPU and UCM predoctoral fellowships,respectively.
文摘Functional Tregs play a key role in tumor development and progression,representing a major barrier to anticancer immunity.The mechanisms by which Tregs are generated in cancer and the influence of the tumor microenvironment on these processes remain incompletely understood.Herein,by using NMR,chemoenzymatic structural assays and a plethora of in vitro and in vivo functional analyses,we demonstrate that the tumoral carbohydrate A10(Ca10),a cell-surface carbohydrate derived from Ehrlich’s tumor(ET)cells,is a heparan sulfate-related proteoglycan that enhances glycolysis and promotes the development of tolerogenic features in human DCs.Ca10-stimulated human DCs generate highly suppressive Tregs by mechanisms partially dependent on metabolic reprogramming,PD-L1,IL-10,and IDO.Ca10 also reprograms the differentiation of human monocytes into DCs with tolerogenic features.In solid ET-bearing mice,we found positive correlations between Ca10 serum levels,tumor size and splenic Treg numbers.Administration of isolated Ca10 also increases the proportion of splenic Tregs in tumor-free mice.Remarkably,we provide evidence supporting the presence of a circulating human Ca10 counterpart(Ca10H)and show,for the first time,that serum levels of Ca10H are increased in patients suffering from different cancer types compared to healthy individuals.Of note,these levels are higher in prostate cancer patients with bone metastases than in prostate cancer patients without metastases.Collectively,we reveal novel molecular mechanisms by which heparan sulfate-related structures associated with tumor cells promote the generation of functional Tregs in cancer.The discovery of this novel structural-functional relationship may open new avenues of research with important clinical implications in cancer treatment.
