CD103 Dendritic Cells Research Articles

Phenotypical and functional characterization of teleost mucosal CD8α+ dendritic cells

Although fish constitute the most ancient animal group in which an acquired immune system is present, the presence of dendritic cells (DCs) in teleost has only been briefly addressed and the identification of a specific DC subset in teleost remained elusive due to the lack of specific antibodies. In mice, CD8 DCs from lymphoid tissues have the capacity of cross-presenting extracellular antigens to T cells through MHC I, similarly to tissue derived CD103 DCs and the human CD141 DC population. In the current study, we have identified in trout a subpopulation of leukocytes of large size and high complexity co-expressing MHC II, CD8CD103 and CD141. These cells, mostly present in mucosal tissues, exhibit functional characteristics of DCs and thus provide the first evidence of a specific DC-like subtype in teleost and support the hypothesis of a common origin for all mammalian antigen cross-presenting cells. In the current study, we have compared the functional and phenotypical characteristics of these DCs in different mucosal tissues (skin, gills and intestine), analyzing their phagocytic ability, their T cell activating capacity, their responsiveness to TLR ligands and the expression of DC-specific markers. Interestingly, this DC subtype exhibited specific phenotypes and functionalities in skin, gills and intestine, suggesting important differences in their activation state depending on their location. These results shed light on how a specific subset of mucosa-resident DCs triggers local responses in the different fish mucosal tissues.

Regulating the expression of CD80/CD86 on dendritic cells to induce immune tolerance after xeno-islet transplantation

BackgroundAntigen present cells (APCs) have been demonstrated to play dual roles in immune tolerance. Recently, compelling evidence indicates that APCs that express CD80, but not CD86 can protect allograft. We investigated whether modulation of CD80 in dendritic cells (DCs) offer protection for xeno-islets. MethodsIn vitro, isolated mature murine DCs received untransfection, transfection with CD86 siRNA or negative control siRNA. The DCs were used in mixed lymphocyte reaction in which rat islets and murine splenocytes were further added. On day 3 of co-culturing, the proliferation of lymphocytes was measured and interleukin (IL)-2, IL-4, IL-10, transforming growth factor β (TGF-β), interferon γ (INF-γ) and indoleamine 2,3-dioxygenase (IDO) from the supernatants were determined. Islets viability and function were also assessed. In vivo, streptozotocin-induced diabetic mice underwent rat islets transplantation were pre-treated with above DCs. At designated time, xeno-islets were subjected to histopathology, immunohistochemistry, survival time and functional tests. Peripheral blood T lymphocyte profiles were also examined. ResultsCD86-silenced-DCs had unchanged expression of CD80 and significantly suppressed the proliferation of lymphocytes. CD86-silenced-DCs simultaneously reduced IL-2 and INF-γ and increased IL-10, TGF-β and IDO, while had minimal effect on IL-4. The CD86-silenced-DCs also improved cell viability and function of xeno-islets when compared to untransfection and transfection control groups. In xeno-islets transplanted diabetic mice, transfer of CD86-silenced-DCs resulted in improved histopathology and dramatically prolonged survival time of the islets. These effects were also mirrored by the functional tests. Further analysis revealed that CD86-silenced-DCs had up-regulated levels of CD4+CD25+T cells in the peripheral blood compared to the other groups. ConclusionsCD86-silenced-DCs induced immune tolerance of rat xeno-islets in recipient diabetic mice with up-regulated peripheral blood CD4+CD25+T cells.

The immune-modulatory effects of a mixed herbal formula on dendritic cells and CD4+ T lymphocytes in the treatment of dust mite allergy asthma and perennial allergic rhinitis

Objective: Asthma and allergic rhinitis are chronic inflammatory diseases of the conducting nasal airway. Traditional Chinese medicine has long been used for supplemental therapy of allergic diseases, especially asthma and allergic rhinitis. We previously reported the effects of a mixed herbal formula in patients with allergic rhinitis. However, the immune-modulatory mechanism underlying the effects of herbal medicine for the treatment of allergic diseases remains unclear. Methods: We investigated the physiologic changes in dendritic cell (DC) and CD4+ T cell activity in patients with asthma and allergic rhinitis who were treated with a mixed herbal formula composed of Xin-yi-san + Xiao-qing-long-tang + Xiang-sha-liu- jun-zi-tang. Specifically, we set up in vitro autologous or heterologous co-culture experiments between DCs and CD4+ T cells, and used flow cytometry and ELISA to analyze the expression of surface molecules on DCs and the release of cytokines by CD4+ T cells. Results: Expression of HLA-DR on DCs was suppressed following treatment with the mixed herbal formula. Surface expression of CD40, CD54 and CD86 on DCs was also attenuated after treatment. In autologous co-cultures, CD4+ T cells increased their IL-10 production while decreasing TNF-α production. In heterologous co-cultures, IL-10 secretion by T cells was enhanced, while IL-12, IL-4, IL-5 and TNF-α secretion were reduced. Conclusion: Our mixed herbal formula attenuated the allergic reaction by modifying the physiologic function of the DC–CD4+ T cell interaction. Further investigations are necessary to understand the mechanism of immune modification mediated by the mixed herbal formula.

Male microbiota protects female BWF1 mice from lupus and death by restoring CD103DC function possibly via metabolite(s) production (THER5P.914)

Abstract Alterations in microbiota composition are associated with autoimmune diseases. Little is known about the effect of microbial metabolite production on disease development. CD103 dendritic cells (CD103DC) induce regulatory T cells (iTregs) in the periphery. We have found that lupus-resistant male BWF1 mice exhibit increased disease incidence/mortality when treated with anti-CD103 antibody. Female CD103DC exhibit lower tolerogenic function than male cells in vitro and in vivo (i.e., oral tolerance) possibly due to a defect in the retinoic acid synthesis pathway. We also found that microbiota composition differed significantly between female and male BWF1 mice, and transfer of male microbiota decreased autoantibody production in female BWF1 mice. Here we report that transfer of male microbiota prevents kidney disease and dramatically increases survival of female BWF1 mice which correlates with enhanced female CD103DC function in both in vitro and in vivo assays, and increased iTregs. Furthermore, our preliminary study suggests that treatment with anti-CD103 antibody prevents male microbiota-mediated protection. Finally, metabolomic analysis of feces from female and male BWF1 mice revealed significant quantitative differences in 17 metabolites, including one that exhibits retinoid X receptor agonist activity. Taken together, these data suggest that male microbiota may protect against lupus through the production of metabolite(s) that enhance the retinoic acid synthesis pathway.

Effect of CD40 silenced dendritic cells by RNA interference on mice skin allograft rejection.

Tolerogenic dendritic cells (DCs) play a critical role in inducing and maintaining tolerance. CD40 is a member of tumor necrosis factor receptor super family and is a potent T-cell costimulatory molecule. Therefore, in this study we evaluated the effect of CD40 silenced DCs by RNA interference on mice skin allograft rejection. Skin transplantation was performed from C57BL/6 to BALB/c mouse. Skin allograft recipients were assigned to four groups (n = 5). CD40 downregulated DCs were injected to the BALB/c mice intravenously 7 days before transplantation. Then, graft survival time, Treg generation, CD4(+) and CD8(+) T cells infiltration and cytokine levels in serum of this group were compared with those of untreated and cyclosporine groups. In comparison with untreated group, BALB/c mice injected with CD40 siRNA transfected DCs showed an increased graft survival time, Treg cells, IL-4 and IL-10 cytokine levels as well as decreased number of intragraft CD4(+) and CD8(+) T cells. IFN-γ and IL-12 secretion were diminished, too. Taken together, these data demonstrate that downregulation of CD40 in DCs can expand Treg cells and increase skin allograft survival.

NLRP10-Deficient Mice Reveal a Crucial Role for Dendritic Cell Activity in the Initiation of the Allogeneic Response to Transfused Red Blood Cells

The generation of antibodies against transfused red blood cells (RBCs) can pose a serious health risk, especially in chronically transfused patients requiring life-long transfusion support; yet our understanding of what immune signals or cells dictate when someone will become alloimmunized is lacking. Every non-autologous red cell unit has multiple antigens foreign to the transfused recipient; some people respond to these foreign antigens with an adaptive immune response and some do not. Given the now well established role of innate immune signals in regulating adaptive immunity, understanding if and how innate immunity is triggered during transfusion may allow development of therapies to prevent alloimmunization in chronically transfused subjects such as those with myelodysplasia or hemoglobinopathies. We have established a murine model system in which we can evaluate both the role of particular innate immune stimuli as well as particular cells of the immune system in regulating the allogeneic response to transfused red blood cells. A particularly useful transgenic “HOD mouse” has been engineered, which encodes a triple fusion protein and provides a unique tool to directly assess both RBC-specific T and B cell responses. This RBC-specific antigen contains the model protein antigen hen egg lysozyme (HEL) fused to chicken ovalbumin (OVA) fused to the human Duffybblood group antigen (HEL-OVA-Duffy) as an integral membrane protein under control of the beta globin promoter. Transfusion of genetically targeted mice lacking various innate immune receptors allows us to screen for important immune pathways regulating the response to allogeneic RBCs.Using these models, we recently discovered that mice lacking the NOD-like receptor NLRP10 fail to develop alloimmunity to transfused red blood cells. Surprisingly, the early innate immune cytokine response, including IL-6, IL-1beta and TNF-alpha, was unaffected in mice lacking NLRP10. Yet both B cell and T cell activation in the spleen to the transgenic transfused RBCs was abrogated. Inclusion of OVA in the alloantigen of the HOD mice allows us to readily study naïve CD4+ T cell activation following transfusion by using the OTII T cell receptor (TCR) transgenic mice in which essentially all T cells express one antigen receptor specific for a peptide of OVA. By tracking rounds of cell division we found that adoptively transferred OTII undergo more than 5-8 rounds of division in the spleen three days following transfusion of HOD RBCs in WT recipients. In contrast, no OTII proliferation was observed in NLRP10-deficient mice following OTII adoptive transfer and HOD RBC transfusion, suggesting that T cells are failing to receive activation signals by splenic antigen presenting cells. We have previously demonstrated that NLRP10-deficient dendritic cells fail to migrate from peripheral tissues such as the skin to draining lymph nodes. Our preliminary data now suggest that NLRP10-deficient dendritic cells are able to process and present RBC-derived antigens, but do not migrate to T cell zones in the spleen to prime naïve RBC-specific T cells. The relative role of dendritic cells, B cells and macrophages in the induction of erythrocyte alloimmunization remain unclear. Further, the need for DC migration within the spleen in the induction of alloimmunity to transfused RBCs has not been addressed. These mice allow us for the first time to answer these fundamental immunologic questions during transfusion. Future work will aim to determine how dendritic cell movement within the spleen is regulated during transfusion in NLRP10-deficient mice and the specific role of splenic dendritic cells in CD4+ T cell priming to allogeneic RBCs. DisclosuresNo relevant conflicts of interest to declare.

Dendritic cell CD83 homotypic interactions regulate inflammation and promote mucosal homeostasis.

Dendritic cells (DCs) form an extensive network in the intestinal lamina propria, which orchestrates the mucosal immune response. Alterations in DC function can predispose to inflammatory bowel disease, although by unknown mechanisms. We show that CD83, a highly regulated DC cell surface protein, modulates the immune response to prevent colitis. Mice with a conditional knockout of CD83 in DCs develop exacerbated colitis following dextran sodium sulfate challenge, whereas mucosal overexpression of CD83 inhibits DC inflammatory response and protects against colitis. These CD83 perturbations can be modeled in vitro where we show that CD83 homotypic interaction occurs via cell–cell contact and inhibits pro-inflammatory responses. CD83 knockdown or cytoplasmic truncation abrogates the effects of homotypic binding. We demonstrate that CD83 homotypic interaction regulates DC activation via the mitogen-activated protein kinase pathway by inhibiting p38α phosphorylation. Our findings indicate that CD83 homotypic interactions regulate DC activation and promote mucosal homeostasis.

Abstract 642: Renal Denervation Prevents Dendritic Cell Activation and Renal T Cell Infiltration and Subsequent Renal Damage in Mice with Angiotensin II-induced Hypertension

Hypertension is associated with increased sympathetic outflow and subsequent activation of adaptive immunity. We hypothesized that renal sympathetic nerves activate dendritic cells, and that these in turn cause T cells to proliferate and accumulate and the eventual end-organ damage in the kidney. To test this, we performed bilateral renal denervation (RDN) in C57BL/6 mice by applying phenol to the renal artery and cutting large visible nerves. One week later, mice received an infusion of angiotensin II (490 ng/kg/min) subcutaneous for 14 days. RDN lowered the hypertensive response to angiotensin II infusion (130±3 vs. 161±3 mmHg) as measured by telemetry, and also prevented renal fibrosis, albuminuria and nephrinuria caused by angiotensin as measured by Masson Trichrome stain and ELISA. By flow cytometry, we found that RDN reduced accumulation of total T cells and CD44hi (memory) T cells in the kidney. Angiotensin II infusion increased expression of the maturation marker CD80 in dendritic cells (DCs) of the kidney by 2 to 3-fold, and increased IL-1α, IL-1β, and IL-6 production by splenic DCs by 4 to 6-fold. These increases were attenuated by RDN. We also found that angiotensin II infusion increased VCAM-1 and decreased eNOS and Klf4 mRNA levels in the kidney as measured by real time RT PCR, and these changes were prevented by RDN. We conclude that renal sympathetic nerves contribute to dendritic cell activation, and subsequent T cell infiltration and end-organ damage in the kidney in the development of hypertension. Sympathetic modulation of VCAM-1, eNOS and Klf4 may predispose to inflammatory cell infiltration and renal inflammation.

IL-17/Th17 pathway is activated in acne lesions.

The mechanisms of inflammation in acne are currently subject of intense investigation. This study focused on the activation of adaptive and innate immunity in clinically early visible inflamed acne lesions and was performed in two independent patient populations. Biopsies were collected from lesional and non-lesional skin of acne patients. Using Affymetrix Genechips, we observed significant elevation of the signature cytokines of the Th17 lineage in acne lesions compared to non-lesional skin. The increased expression of IL-17 was confirmed at the RNA and also protein level with real-time PCR (RT-PCR) and Luminex technology. Cytokines involved in Th17 lineage differentiation (IL-1β, IL-6, TGF-β, IL23p19) were remarkably induced at the RNA level. In addition, proinflammatory cytokines and chemokines (TNF-α, IL-8, CSF2 and CCL20), Th1 markers (IL12p40, CXCR3, T-bet, IFN-γ), T regulatory cell markers (Foxp3, IL-10, TGF-β) and IL-17 related antimicrobial peptides (S100A7, S100A9, lipocalin, hBD2, hBD3, hCAP18) were induced. Importantly, immunohistochemistry revealed significantly increased numbers of IL-17A positive T cells and CD83 dendritic cells in the acne lesions. In summary our results demonstrate the presence of IL-17A positive T cells and the activation of Th17-related cytokines in acne lesions, indicating that the Th17 pathway is activated and may play a pivotal role in the disease process, possibly offering new targets of therapy.

Peyerʼs Patches Play a Protective Role in Nonsteroidal Anti-inflammatory Drug-induced Enteropathy in Mice

Peyer's patches (PPs) play a major role in mucosal immunity. However, their roles in nonsteroidal anti-inflammatory drug-induced enteropathy are poorly understood. Wild-type (WT) and PP-null mice were injected with indomethacin. Twenty-four hours later, the cellular profiles and cytokine levels in the PPs, mesenteric lymph nodes (MLNs), and lamina propria (LP) of the small intestine were measured. WT and PP-null mice were given antibiotics before indomethacin treatment to evaluate enteropathy. Naive CD4 T cells were co-cultured with CD103 or CD103 dendritic cells (DCs) to analyze the interleukin (IL)-10 expression levels. Finally, WT mice adoptively transferred with CD103 or CD103 DCs were injected with indomethacin. The proportion of CD103 DCs in PPs and MLNs and IL-10-expressing CD4 T cells of PPs and the LP increased after indomethacin treatment. The PP-null mice showed greater indomethacin-induced enteropathy, fewer CD103 DCs in their MLNs, and lower proportion of IL-10-expressing CD4 T cells of their LP than WT mice, regardless of commensal bacteria. Naive splenic CD4 T cells co-cultured with CD103 DCs isolated from the MLNs of indomethacin-injected WT mice produced a higher amount of IL-10 compared with those co-cultured with CD103 DCs. Moreover, WT mice that received CD103 DCs showed milder enteropathy than those that received CD103 DCs. PPs play a protective role in nonsteroidal anti-inflammatory drug-induced enteropathy, and this protection is associated with an increase in CD103 DCs and IL-10-producing CD4 T cells in the intestine, independent of the commensal bacteria.

Constitutive β-catenin signaling dysregulates DC differentiation resulting in inability to control microbial infection (INM2P.418)

Abstract The protozoan Toxoplasma gondii is the second most common cause of foodborne illness-related deaths in the US and can be fatal to infants and immunocompromised patients. Dendritic cells (DC) are required for immunity to T. gondii, and recently, DC Wnt/β-catenin signaling has been suggested to control DC tolerance in the intestine. However, the role of this signaling axis in peripheral DC development and function is unknown. Using transgenic mice expressing DC-specific constitutively active β-catenin (DCEx3-/-), we surprisingly found that the splenic CD8α DC and the developmentally related peripheral CD103 DC compartment were significantly expanded relative to corresponding populations in wild-type (WT) animals. Splenic CD8α DC are a source of IL-12, and infection of DCEx3-/- mice with T. gondii resulted in rapid lethality associated with proinflammatory cytokine overproduction. Transcription factor Irf8 drives CD8α and CD103 DC differentiation, and flow cytometric analysis revealed strong upregulation of Irf8 in CD8α DC upon β-catenin stabilization. Confirming this, WT CD8α+Irf8+ DC displayed higher β-catenin levels relative to splenic CD8- DC. Together, our data show that β-catenin targets Irf8 during DC development, resulting in expansion of CD8α DC in the spleen and CD103 DC in the periphery. This is the first study to implicate β-catenin in DC subset differentiation and provides novel insight into the complex transcriptional network of DC development.

Memory B cells are critical in gamma herpes virus driven disease enhancement of a mouse model for MS (BA2P.124)

Abstract Genetic and environmental factors are known to be involved in the development of Multiple Sclerosis. However, the mechanism describing how these factors are responsible for the onset of MS has not been elucidated. One of the environmental factors believed to play an important role in the development of MS is previous infection with the Epstein Barr Virus (EBV). The study of the relationship between MS and EBV remains elusive since EBV only infects humans. We hypothesized that latent EBV infection alters the immune system’s response in genetically predisposed individuals, thereby exacerbating autoimmunity. To address this question our lab previously developed a model where latent infection with murine gamma herpesvirus 68 (γHV-68), the murine homolog to EBV, enhances the symptoms of experimental autoimmune encephalomyelitis (EAE), which closely resembles MS pathogenesis. These enhanced symptoms are driven by the upregulation of CD40 on dendritic cells (DCs) of latently infected mice which drives the priming of a strong TH1 response and a decrease in Tregs frequencies. Latency of γHV-68 mainly occurs in memory B cells and the virus is not found in the DCs driving the TH1 response. Here we demonstrate that latently infected memory B cells are the cells responsible for the upregulation of CD40 in DCs, most likely through the upregulation of type I interferons in DCs. This represents a novel mechanism by which infection with EBV can influence MS and other autoimmune diseases.

Post-transplant cyclophosphamide and bortezomib inhibit dendritic cell maturation and function and alter their IκB and NFκB

Impairing dendritic cell (DC) function to prevent graft versus host disease (GvHD) is an appealing concept. DC antigen presentation is NF-κB pathway-dependent and bortezomib might therefore play a role in preventing alloreactivity. We obtained DC from the blood of patients enrolled in a phase I study using post-transplant cyclophosphamide and bortezomib for prevention of GvHD. Control samples were obtained from patients receiving standard GvHD prevention regimen. Pre-treatment samples were also collected from enrolled patients. DC isolated on days +1, +4, and +7 showed progressive decrease in the expression of maturation markers in comparison to control. In a DC–CD4+ mixed lymphocyte reaction (MLR) where DC isolated from the recipient blood before graft infusion were the stimulator cells, T cell proliferation measured by bromodeoxyuridine (BrdU) integration was decreased in samples obtained on days +14 and +21 in comparison to control group. Finally, measured by real-time PCR, the expression of IκB progressively increased while the expression of NF-κB decreased in DC on days +1, +4, and +7, in comparison to pre-treatment paired controls. We conclude that our data further justify exploring the role of bortezomib in GvHD prevention and propose a novel mechanism of action of bortezomib in DC.

The splicing factor hnRNP C regulates expression of co-stimulatory molecules CD80 and CD40 in dendritic cells

Maturation of dendritic cells is a key step during induction of adaptive immune responses. Multiple pathways and factors are involved in the regulation of dendritic cell maturation. Alternative splicing of pre-mRNA, which is regulated by splicing factors, plays an important role in many biological processes, including immune responses. To understand the roles of splicing factors in the maturation of dendritic cells, we analyzed the expression of the splicing factors hnRNP C and hnRNP A1 during maturation of the mouse dendritic cell line DC2.4 upon treatment with lipopolysaccharides (LPS). The expression of hnRNP C significantly increased after LPS stimulation. Knockdown or overexpression of hnRNP C respectively downregulated or upregulated the expression of nuclear factor-kappa B p65 as well as its downstream targets CD80 and CD40. Our results indicate that hnRNP C regulates the maturation of dendritic cells by affecting the expression of p65, CD80 and CD40.

High glucose induces upregulation of scavenger receptors and promotes maturation of dendritic cells.

BackgroundBoth hyperglycaemia and dendritic cells (DCs) play causative roles in atherosclerosis. However, whether they interact in atherosclerosis remains uncertain. Therefore, we examined whether high glucose could regulate the expression of scavenger receptors responsible for oxidised low-density lipoprotein (oxLDL) uptake in DCs, a critical step in atherogenesis. In addition, we investigated the impact of glucose on DC maturation regarding changes in phenotype and cytokine secretion.MethodsImmature DCs were cultured with different concentrations of glucose (5.5 mmol/L, 15 mmol/L, 30 mmol/L) in the absence or presence of N-acetylcysteine (NAC), SB203580 or Bay11-7082 for 24 hours. We used 30 mmol/L mannitol as a high-osmolarity control treatment. The expression of the scavenger receptors SR-A, CD36 and LOX-1 was determined by real-time PCR and western blot analysis. Furthermore, DCs were incubated with DiI-labelled oxLDL. The DiI-oxLDL-incorporated fraction was investigated by flow cytometry analysis. The intracellular production of ROS in DCs was measured by dichlorodihydrofluorescein (DCF) fluorescence using confocal microscopy. Finally, flow cytometry analysis was used to investigate immunophenotypic protein expression (CD83 and CD86). Supernatant cytokine measurements were used for immune function assays.ResultsThe incubation of DCs with glucose enhanced, in a dose-dependent manner, the gene and protein expression of SR-A, CD36 and LOX-1. This effect was partially abolished by NAC, SB203580 and Bay11-7082. Incubation of DCs with mannitol (30 mmol/L) did not enhance these scavenger receptors’ expression. High glucose upregulated the production of ROS and expression of p38 MAPK in DCs. NAC partially reversed p38 MAPK upregulation. High glucose increased the oxLDL-uptake capacity of DCs. Blockage of the scavenger receptors SR-A and CD36 reduced oxLDL uptake, but blockage of LOX-1 did not. Furthermore, high-glucose (15 mmol/L or 30 mmol/L) treatment increased CD86 and CD83 in DCs. High glucose also increased IL-6 and IL-12 secretion and decreased IL-10 secretion.ConclusionHigh glucose can increase the expression of the scavenger receptors SR-A, CD36 and LOX-1, which can increase the oxLDL-uptake capacity of DCs. High glucose induces a proinflammatory cytokine profile in human DCs, leading to DC maturation. These results support the hypothesis that atherosclerosis is aggravated by hyperglycaemia-induced DC activation and oxLDL uptake.

Antitumor effects and mechanisms of dendritic cells stimulated by sCD40L on ovarian cancer cells in vitro

ObjectiveThis study aimed to examine the expression of immune suppression factors and the mechanisms of antitumor effects of cord blood dendritic cells (DCs) stimulated by soluble cluster of differentiation 40 ligand (sCD40L) and cytokines in vitro in ovarian cancer patients.MethodsThe expression levels of interleukin (IL)-10 and transforming growth factor (TGF)-β messenger RNA in peripheral blood were detected by reverse transcription polymerase chain reaction; expression levels of CD80 and CD86 in DCs stimulated by sCD40L were detected using flow cytometry and confocal laser scanning microscopy.ResultsExpression levels of IL-10 and TGF-β genes in the peripheral blood of ovarian cancer patients were significantly increased compared with patients with benign ovarian tumors (P < 0.05). The expression levels of CD80 and CD86 in DCs cultured in the granulocyte-macrophage colony-stimulating factor + IL-4 + stem cell factor + Flt-3 ligand + sCD40L group were significantly increased compared with those in the control group, as assessed by flow cytometry and confocal laser scanning microscopy (P < 0.05).ConclusionA variety of cytokines in combination with sCD40L can promote the proliferation of cord blood-derived DCs and induce their maturation as well as stimulating a specific antitumor response.

Induction of CD4+CD25+ T Cells and Control of Cardiac Allograft Rejection by CD40/CD40L Costimulatory Pathway Blockade in Mice

BackgroundRejection is a major problem in organ transplantation. We speculated that dendritic cells (DCs) with low expression of CD40 may inhibit T-cell responses providing protective effects on organ transplantions. MethodsRNA interference (RNAi) is an effective approach to degrade RNA levels of a target gene. We used RNAi to reduce CD40 levels in mouse bone marrow-derived DCs. Allogeneic T-lymphocyte proliferation stimulated by DCs was assessed in mixed lymphocyte reactions. A mouse model of heterotopic abdominal heart transplantation was performed to evaluate survival times and histologic grade of acute rejection at 7 days after transplantation. CD4+CD25+ regulatory T cells (Tregs) in peripheral blood were quantified by flow cytometry. ResultsMouse DCs with reduced CD40 expression lowered the proliferation of recipient T cells. More DCs with silenced CD40 delayed cardiac allograft rejection. ConclusionsReduction of CD40 in DCs induced peripheral Tregs and delayed cardiac allograft rejection.

How Can Chemoimmunotherapy Best be Used for the Treatment of Colon Cancer?

Immunity, inflammation & colon cancer The colon, as part of the intestine, is constantly exposed to a variety of nutrients and commensal bacteria. These exogenous stimuli shape the particular tissue-specific immune system in the colon. This system is rich in innate lymphoid cells, CD103 dendritic cells, IgA-secreting plasma cells, Tregs and Th17 cells. This unique immune milieu is regulated by endogenous signals (e.g., TGF-β) that work in concert with exogenous signals derived from bacteria, or nutrients such as retinoic acid derived from vitamin A, or aryl hydrocarbon receptor ligands present in some vegetables [1]. However, this subtle equilibrium between nutrients, microbiota and the colonic immune system can be unbalanced when a chronic inf lammatory process settles in the colon. Chronic inflammation is an enabling factor for the tumorigenic process [2]. Indeed, the colon is the organ that best reflects the link between chronic inflammation and cancer. Intestinal inf lammatory disease is associated with an increase in cancer risk. Moreover, several studies have associated the prolonged uptake of antiinflammatory drugs with a reduced risk of colon cancer [3].

The effect of budesonide on thymic stromal lymphopoietin receptor and cytokine profile of dendritic cells in OVA-induced asthma in mice

To investigate the effect of budesonide (BUD) on thymic stromal lymphopoietin receptor (TSLPR) of dendritic cells (DCs) in OVA-induced mouse asthma models and to explore the mechanisms by studying the effect of BUD on function of DCs from the model. Eighteen BALB/c female mice were randomly divided into a control group, an asthma group and a BUD intervention group, with 6 mice in each group. Mice were sensitized and challenged with ovalbumin (OVA) to establish the asthmatic model. The bronchoalveolar lavage fluid (BALF) and DCs of spleen from the 3 groups were harvested and the supernatants of BALF and DCs were analyzed for levels of TSLP and TSLPR, respectively, by commercially available ELISA kit. The percentage of eosinophils (EOS) in BALF was counted. The expression of CD₄₀, CD₈₀ and CD₈₆ in DCs was detected by FACS. The DCs were then washed, and co-cultured in vitro with autologous T cells purified by a nylon cotton column. The supernatants of DC-T co-culture were collected after 72 h incubation, and analyzed for levels of interleukin-5 (IL-5) and interferon-γ (IFN-γ) by ELISA. The levels of TSLP in BALF and TSLPR in DCs from the asthma group were significantly increased compared with the control group [(44.0 ± 5.1) ng/L vs (14.2 ± 3.6) ng/L, P < 0.01 and (19.7 ± 2.2) ng/L vs (10.4 ± 1.2) ng/L, P < 0.05, respectively]. The expression of CD₄₀, CD₈₀ and CD₈₆ of DCs and IL-5 in the culture supernatants of DC-T co-culture was significant up-regulated in the asthma group compared with the control group (P < 0.05). Furthermore, the addition of BUD reduced the expression of CD₄₀, CD₈₀, CD₈₆, TSLPR in DCs, IL-5 in the culture supernatants of DC-T co-culture, TSLP and EOS in BALF. The level of INF-γ in the DC-T co-culture supernatants of the 3 groups did not achieve statistical significance (F = 0.82, P > 0.05). These results demonstrate that the therapeutic activity of BUD in asthmatic mice may be related to modulation of Th1 and Th2 cell functions and this effect is probably mediated through the TSLP-DC pathway.

A critical role of dendritic cells in CD8 T cell IL-10 expression during inflammatory response triggered by CD40-activated B cells (159.16)

Abstract CD40LBTg mice, expressing a CD40 ligand (CD40L) transgene on B cells, represent a model for human diseases where B cells aberrantly express CD40L or receive excess CD40/CD40L signaling under inflammatory conditions. Here, we show that B cells expressing transgenic CD40L are capable of priming CD8 T cells and generate strong antigen-specific cytotoxicity. Adoptively transferred SIINFEKL peptide-loaded B cells from CD40LBTg but not wild type mice were able to activate self-reactive OT-I CD8 T cells upon immunization with OVA plus alum and trigger diabetes in RIP-OVA mice by enhancing the help of endogenous self-reactive CD4 T cells. CD40L expressing B cells also trigger spontaneous activation of splenic CD8 T cells, which rapidly up-regulate PD-1, Blimp-1 and LAG-3 and lose cytotoxicity along with IL-10 expression via interaction with PDL-1hi CD11c+ dendritic cells in T cell zones. Thus, CD11c+ dendritic cells from CD40LBTg mice exhibit regulatory phenotype, which block granzyme B expression and preferentially induce IL-10 expression in activated CD8 T cells. These results demonstrate that constitutive CD40 signaling on B cells under inflammation increases the risk of breaking peripheral CD8 T cell tolerance. However, the presence of CD40-activated B cells results in PDL-1hi CD11c+ dendritic cells, which exhibit a regulatory role to dampen harmful self-reactive cytotoxicity by promoting IL-10 expression in CD8 T cells.