CD103 Dendritic Cells Research Articles

In vitro dendritic cell maturation isolated from healthy people and patients with Staphylococcus aureuscaused chronic osteomyelitis

Here we present the data comparing maturation of peripheral blood mononuclear cell-derived dendritic cells (DCs) isolated from healthy volunteers and Staphylococcus aureus-positive patients with chronic osteomyelitis. Dendritic cells were cultured in a standard maturation cell medium (RPMI-1640, supplemented with antibiotics, L-glutamine, 15% calf embryonic serum) added with interleukin-4 and granulocyte-macrophage colony-stimulating factor, followed by adding a stimulating factor cocktail containing interleukin-1, tumor necrosis factor-, interleukin-6, and prostaglandin E2. Dendritic cell maturation was analyzed by estimating visual characteristics under Zeiss ODSERVER.Z1 inverted microscope using Axiovision Rel.4.8 imaging software as well as light and phase-contrast microscopy at magnification of 40, 100, 200, 400, 630. Dendritic cell immunophenotyping was carried out by using a panel of anti-human monoclonal antibodies: anti-CD80 FITC-conjugated, anti-CD86 (B72) PE-conjugated, anti-HLA-DR PC7-conjugated (all from Beckman Coulter, USA), anti-CD14 PerCP-Cy5.5-conjugated, anti-CD83 APC-conjugated, anti-CD40 PE-Cy7-conjugated (Becton Dickinson, USA) as well as isotype-matched control antibodies on the FACS Canto II f low cytometer (Becton Dickinson, USA). It was shown that while maturation dendritic cells derived both from patients or volunteers increased in size and underwent dendrite formation. Moreover, expression of CD86, CD83, CD80, and CD40 markers on dendritic cells derived from patients vs. volunteers was lowered. However, DC stimulation resulted in significantly increased percentage of DCs positive for CD83 DCs co-stimulation molecules CD86, CD80, CD40 chronic osteomyelitis. However, such differences found in immature DCs in both groups disappeared upon maturation, so that expression of the key markers on day 10 was maintained at close level. In particular, expression of CD83 differentiation marker and the CD80 co-stimulation molecule on DCs from patients vs. volunteers was increased stronger. Thus, a maturation potential in DCs isolated from patients with Staphylococcus aureus-caused chronic osteomyelitis was not impaired in vitro. The data obtained open up an opportunity to use dendritic cells as a natural adjuvant-substituting component for development of individualized vaccines in treatment and prevention of recurrent chronic osteomyelitis.

Failure of Decidualization and Maternal Immune Tolerance Underlies Uterovascular Resistance in Intra Uterine Growth Restriction.

Failure of uterine vascular transformation is associated with pregnancy complications including Intra Uterine Growth Restriction (IUGR). The decidua and its immune cell populations play a key role in the earliest stages of this process. Here we investigate the hypothesis that abnormal decidualization and failure of maternal immune tolerance in the second trimester may underlie the uteroplacental pathology of IUGR. Placental bed biopsies were obtained from women undergoing elective caesarian delivery of a healthy term pregnancy, an IUGR pregnancy or a pregnancy complicated by both IUGR and preeclampsia. Decidual tissues were also collected from second trimester terminations from women with either normal or high uterine artery Doppler pulsatile index (PI). Immunohistochemical image analysis and flow cytometry were used to quantify vascular remodeling, decidual leukocytes and decidual status in cases vs. controls. Biopsies from pregnancies complicated by severe IUGR with a high uterine artery pulsatile index (PI) displayed a lack of: myometrial vascular transformation, interstitial, and endovascular extravillous trophoblast (EVT) invasion, and a lower number of maternal leukocytes. Apoptotic mural EVT were observed in association with mature dendritic cells and T cells in the IUGR samples. Second trimester pregnancies with high uterine artery PI displayed a higher incidence of small for gestational age fetuses; a skewed decidual immunology with higher numbers of; CD8 T cells, mature CD83 dendritic cells and lymphatic vessels that were packed with decidual leukocytes. The decidual stromal cells (DSCs) failed to differentiate into the large secretory DSC in these cases, remaining small and cuboidal and expressing lower levels of the nuclear progesterone receptor isoform B, and DSC markers Insulin Growth Factor Binding protein-1 (IGFBP-1) and CD10 as compared to controls. This study shows that defective progesterone mediated decidualization and a hostile maternal immune response against the invading endovascular EVT contribute to the failure of uterovascular remodeling in IUGR pregnancies.

ADAR1 Is Required for Dendritic Cell Subset Homeostasis and Alveolar Macrophage Function.

RNA editing by adenosine deaminases acting on dsRNA (ADAR) has become of increasing medical relevance, particularly because aberrant ADAR1 activity has been associated with autoimmunity and malignancies. However, the role of ADAR1 in dendritic cells (DC), representing critical professional APCs, is unknown. We have established conditional murine CD11c Cre-mediated ADAR1 gene ablation, which did not induce general apoptosis in CD11c+ cells but instead manifests in cell type-specific effects in DC subpopulations. Bone marrow-derived DC subset analysis revealed an incapacity to differentiate CD103 DC+ in both bulk bone marrow and purified pre-DC lineage progenitor assays. ADAR1 deficiency further resulted in a preferential systemic loss of CD8+/CD103+ DCs, revealing critical dependency on ADAR1, whereas other DC subpopulations were moderately affected or unaffected. Additionally, alveolar macrophages were depleted and dysfunctional, resembling pulmonary alveolar proteinosis. These results reveal an unrecognized role of ADAR1 in DC subset homeostasis and unveils the cell type-specific effects of RNA editing.

Fms-Like Tyrosine Kinase 3-Ligand Contributes to the Development and Function of the Subpopulation of CD8α+ Plasmacytoid Precursor Dendritic Cells in CD8+ /TCR- Facilitating Cells.

Facilitating cells (FC) are a CD8+ TCR- bone marrow subpopulation that enhance engraftment of purified hematopoietic stem cells (HSC) and induce antigen-specific CD4+ CD25+ FoxP3+ regulatory T cell (Treg) in vivo. The major subpopulation in FC resembles plasmacytoid precursor dendritic cells (p-preDC) both phenotypically and functionally. Here, we report that the number of FC was significantly reduced in Fms-like tyrosine kinase 3-ligand-knockout (Flt3-L-KO) mice. Specifically, there was a selective decrease in the B220+ CD11c+ CD11b- p-preDC FC subpopulation. The p-preDC FC subpopulation in FC total is restored after Flt3-L administration to Flt3-L-KO mice. FC from Flt3-L-KO donors exhibit impaired facilitation of allogeneic HSC engraftment in ablatively conditioned mice (B6 → NOD) as well as in mice conditioned with reduced intensity conditioning (B6 → BALB/c). In addition, the number of CD4+ CD25+ Foxp3+ Treg from Flt3-L-KO mice is significantly decreased. This was associated with the expression of chemokine receptor CXCR3+ or CCR5+ on Treg. Treg from the spleen of Flt3-L-KO mice showed impaired facilitation of engraftment of allogeneic HSC compared to wild-type Treg. Flt3-L treatment significantly expanded Treg, and restored their facilitating function. These results suggest that Flt3-L is an important growth factor in the development and homeostasis of p-preDC FC and in the role of FC inducing generation of Treg. Flt3-L provides potent immunoregulatory properties that may be clinically useful to improve tolerance induction and enhance the function of allogeneic cell therapies. Stem Cells 2018;36:1567-1577.

Synergic Effects of CD40 and CD86 Silencing in Dendritic Cells on the Control of Allergic Diseases

Background: We previously reported that siRNA-induced CD40-silenced dendritic cells (DCs) inhibit allergic responses and symptoms. However, more potent therapies are needed. To our knowledge, synergic effects of gene silencing in DCs by ≥2 siRNAs have not been reported to control allergic diseases. Therefore, we investigated the synergistic effects of the silencing of CD40 and CD86 in DCs on allergic responses. Methods: Mice were treated with CD40/CD86-silenced DCs, which were transfected with CD40/CD86 siRNAs and pulsed with ovalbumin (OVA) antigen. The effects of these DCs on allergic symptoms and allergic responses were estimated. Results: The administration of CD40/CD86-silenced OVA-pulsed DCs significantly inhibited the number of sneezes and nasal rubbing movements, the number of eosinophils in the nasal mucosa, and the level of OVA-specific IgE when compared with those for CD40- or CD86-silenced OVA-pulsed DCs alone (p < 0.01). These inhibitory effects were detected before sensitization as well as after the establishment of allergic rhinitis. CD40/CD86-silenced OVA-pulsed DCs did not inhibit KLH-induced allergies. Foxp3 gene expression was significantly upregulated in CD40-silenced DCs compared to in CD86-silenced DCs (p < 0.01). IL-4 production by T cells was suppressed more substantially when using CD86-silenced DCs than with CD40-silenced DCs (p < 0.01). Conclusions: These results indicate, for the first time, that siRNA-induced CD40/CD86-silenced antigen-specific DCs have greater inhibitory effects against allergic responses than those of CD40- or CD86-silenced antigen-specific DCs alone. This study also suggests that the synergic effects of gene silencing in DCs by ≥2 siRNAs are useful for the control of allergic diseases. Thus, owing to the synergistic effects, CD40 and CD86 silencing has the potential to substantially improve the treatment of allergic diseases.

Lymphoid aggregates in desmoplastic melanoma have features of tertiary lymphoid structures.

Desmoplastic melanomas (DM) have unique and challenging clinical presentations and histomorphology. A characteristic feature is the presence of scattered lymphoid aggregates. However, the nature of these aggregates is not defined. We hypothesized that they may be tertiary lymphoid structures (TLS), and may be associated with programmed death ligand 1 (PD-L1) expression. We searched our tissue database for 'pure' DMs and for scars as control tissues, collected clinical information, and reviewed H&E histology. We performed multispectral imaging after staining for CD8, CD20, PNAd, FoxP3, CD83, and Ki67, and assessed PD-L1 expression by immunohistochemistry. Pure DM samples were evaluable in 11 patients. All had desmoplastic stroma and lymphoid aggregates on H&E. The lymphoid aggregates of eight of the 11 (72%) DM samples and only three of the 11 scars contained features of TLS, defined as distinct clusters of B cells and CD8 T cells, CD83 dendritic cells in T-cell zones, and PNAd vasculature resembling high endothelial venules. PD-L1 was expressed by at least 1% of melanoma cells in six and by at least 5% of immune cells in 10 of the 11 DM samples. We found that most lymphoid aggregates in DM are organized, classical TLS. PD-L1 expression was detected in most cases and was highest in two cases of DM with TLS. However, low PD-L1 expression in some cases suggests that some DM cells may be unresponsive to interferon-γ. TLS support antigen presentation and T-cell responses in chronic inflammation and cancer. Their presence in DM likely reflects an adaptive immune response, which may be enhanced with immune therapies.

CD103 expression by DCs: a new player in lung cancer immunity.

Abstract Despite the use of various therapies, lung cancer remains one of the world’s leading causes of death. Cancer immunotherapy is a promising therapeutic avenue, however, molecular and cellular mechanisms involved in cancer immunity remain elusive. Dendritic cells (DCs), which play an important role in CD8+ T cell activation in cancer immunity, can be divided into two major populations, namely DC1 and DC2, and respectively identified by XCR1/CD103 and Sirpα/CD11b expression. Importantly, studies have demonstrated that DC1s promote cancer immune responses. Furthermore, CD103+ DC1s specialize in the transport of tumor antigens to draining lymph nodes and cross-presentation. However, the influence of the cancer environment, where inflammatory factors (such as TNF) and various inflammatory cells are found, on CD103 expression by DC has never been studied. To verify whether lung cancer-induced inflammation modulates CD103 DC population, fresh lung and splenic DCs were isolated in wild type (WT) mice and exposed to GM-CSF (a known inducer of CD103 expression in the lung) with or without TNF. Furthermore, to directly assess the impact of lung cancer on CD103 DC expression, WT mice were euthanized 2 and 3 weeks following intravenous injection of Lewis lung carcinoma (LLC) cells and the percentage of CD103+DC1 was analyzed in lungs. Exposure to TNF blocked the GM-CSF-induced CD103 expression by DCs, independently of the timing at which TNF is added to cultures (before or after GM-CSF). Also, the % of CD103+ DCs gradually decreased in time following LLC injection. This suggests a new mechanism by which lung cancer negatively impacts the function of immune cells to promote cancer development, and could lead to new therapeutic avenues in cancer immunity.

Deletion of IRF8 (Interferon Regulatory Factor 8)-Dependent Dendritic Cells Abrogates Proatherogenic Adaptive Immunity.

Despite an established role for adaptive immune responses in atherosclerosis, the contribution of dendritic cells (DCs) and their various subsets is still poorly understood. Here, we address the role of IRF8 (interferon regulatory factor 8)-dependent DCs (lymphoid CD8α+ and their developmentally related nonlymphoid CD103+ DCs) in the induction of proatherogenic immune responses during high fat feeding. Using a fate-mapping technique to track DCs originating from a DNGR1+ (dendritic cell natural killer lectin group receptor 1) precursor (Clec9a+/creRosa+/EYFP mice), we first show that YFPhiCD11chiMHCIIhi (major histocompatibility complex class II) DCs are present in the atherosclerotic aorta of low-density lipoprotein receptor-deficient (Ldlr-/-) mice and are CD11b-CD103+IRF8hi. Restricted deletion of IRF8 in DCs (Irf8flox/floxCd11cCre ) reduces the accumulation of CD11chiMHCIIhi DCs in the aorta without affecting CD11b+CD103- DCs or macrophages but completely abolishes the accumulation of aortic CD11b-CD103+ DCs. Lymphoid CD8α+ DCs are also deleted. This is associated with a significant reduction of aortic T-cell accumulation and a marked reduction of high-fat diet-induced systemic T-cell priming, activation, and differentiation toward T helper type 1 cells, T follicular helper cells, and regulatory T cells. As a consequence, B-cell activation and germinal center responses to high-fat diet are also markedly reduced. IRF8 deletion in DCs significantly reduces the development of atherosclerosis, predominantly in the aortic sinus, despite a modest increase in total plasma cholesterol levels. IRF8 expression in DCs plays a nonredundant role in the development of proatherogenic adaptive immunity.

Hypoxia enhances indoleamine 2,3-dioxygenase production in dendritic cells.

Hypoxia-associated metabolic reprogramming modulates the biological functions of many immune and non-immune cells, and affects immune response types and intensities. Adenosine and indoleamine 2,3-dioxygenase (IDO) are known immunosuppressors, and adenosine is a hypoxia-associated product. We investigated the impact of hypoxia on IDO production in dendritic cells (DCs). We found that hypoxia (1% O2) enhances IDO production in DCs, and this increase was dependent on the adenosine A3 receptor (A3R), but not A2aR or A2bR. A3R blockade during hypoxia inhibited IDO production in DCs, while A2bR blockade further enhanced IDO production. Activating A2aR had no effect on IDO production. Hypoxia (1% O2) upregulated CD86, CD274, HLA-DR, and CD54, and downregulated CD40 and CD83 in DCs as compared to normoxia (21% O2). IDO inhibition in hypoxia-conditioned DCs reversed MHC-II, CD86, CD54, and CD274 upregulation, but further downregulated CD40 and CD83. Our findings offer guidance for pharmacological administration of adenosine receptor agonists or antagonists with the goal of achieving immune tolerance or controlling insulin resistance and other metabolic disorders via IDO modulation.

Adaptation of the human Cell Line Activation Test (h-CLAT) to Animal-Product-Free Conditions.

Skin sensitisers are substances that can elicit allergic responses following skin contact and the process by which this occurs is described as skin sensitisation. Skin sensitisation is defined as a series of key events, that form an adverse outcome pathway (AOP). Key event three in the AOP is dendritic cell activation that can be modelled by the human Cell Line Activation Test (h-CLAT) and is typified by changes in cell surface markers CD54 and CD86 in dendritic cells. The h-CLAT is accepted at a regulatory level (OECD Test-Guideline (TG)442E) and can be used to assess skin sensitisation potential as part of an integrated approach to testing and assessment (IATA). Stakeholders in the cosmetics and chemical industries have scientific and ethical concerns relating to use of animal derived material and have communicated a strong preference for fully human based in vitro methods. Therefore, we adapted the h-CLAT to animal-product-free conditions and validated the adapted method with the proficiency panel substances in Annex II of TG442E, using 3 independent batches of pooled human serum. The modified method showed equivalence to the validated reference method (VRM), as all proficiency substances were correctly classified. Comparable values for CV75 (concentration yielding 75% cell viability), EC150 and EC200 (concentration yielding RFI of ≥150 for CD86 and ≥200 for CD54) were obtained. Data generated using the adapted method may be used in European REACH submissions, provided the proficiency data is included. We are seeking formal inclusion of the adaptation into TG442E, enabling compliance with global regulations.

Constitutive CD40 Signaling in Dendritic Cells Limits Atherosclerosis by Provoking Inflammatory Bowel Disease and Ensuing Cholesterol Malabsorption

The costimulatory molecule CD40 is a major driver of atherosclerosis. It is expressed on a wide variety of cell types, including mature dendritic cells (DCs), and is required for optimal T-cell activation and expansion. It remains undetermined whether and how CD40 on DCs impacts the pathogenesis of atherosclerosis. Here, the effects of constitutively active CD40 in DCs on atherosclerosis were examined using low-density lipoprotein-deficient (Ldlr-/-) bone marrow chimeras that express a transgene containing an engineered latent membrane protein 1 (LMP)/CD40 fusion protein conferring constitutive CD40 signaling under control of the DC-specific CD11c promoter (DC-LMP1/CD40). As expected, DC-LMP1/CD40/Ldlr-/- chimeras (DC-LMP1/CD40) showed increased antigen-presenting capacity of DCs and increased T-cell numbers. However, the mice developed extensive neutrophilia compared to CD40wt/Ldlr-/- (CD40wt) chimeras. Despite overt T-cell expansion and neutrophilia, a reduction in conventional DC frequency and a dramatic (approximately 80%) reduction in atherosclerosis was observed. Further analyses revealed that cholesterol and triglyceride levels had decreased by 37% and 60%, respectively, in DC-LMP1/CD40 chimeras. Moreover, DC-LMP1/CD40 chimeras developed inflammatory bowel disease characterized by massive transmural influx of leukocytes and lymphocytes, resulting in villous degeneration and lipid malabsorption. Constitutive activation of CD40 in DCs results in inflammation of the gastrointestinal tract, thereby impairing lipid uptake, which consequently results in attenuated atherosclerosis.

CD103+ Dendritic Cell Function Is Altered in the Colons of Patients with Ulcerative Colitis.

Human intestinal innate myeloid cells can be divided into 3 subsets: HLA-DRCD14 cells, HLA-DRCD103 dendritic cells (DCs), and HLA-DRCD14CD103 cells. CD103 DCs generate Treg cells and Th17 cells in the ileum, but their function in the colon remains largely unknown. This study characterized CD103 DCs in the colon and investigated whether these cells are implicated in the pathogenesis of ulcerative colitis (UC). Normal intestinal mucosa was obtained from intact sites of patients with colorectal cancer (n = 24). Noninflamed and inflamed colonic tissues were obtained from surgically resected specimens of patients with UC (n = 13). Among LinCD45HLA-DR intestinal lamina propria cells, CD14 cells and CD103 DCs were sorted and analyzed for microRNA expression of cytokines and toll-like receptors by quantitative real-time polymerase chain reaction. In addition, IL-4/IL-5/IL-13/IL-17/IFN-γ production and Foxp3 expression by naive T cells cultured with CD14 cells and CD103 DCs were analyzed. CD103 DCs in the normal colon showed lower expression of toll-like receptors and proinflammatory cytokines than CD14 cells. Coculture with naive T cells revealed that CD103 DCs generated Treg cells. CD103 DCs from patients with UC did not generate Treg cells, but they induced IFN-γ-, IL-13-, and IL-17-producing CD4 T cells and showed higher expression of IL6 (P < 0.0001), IL23A (P < 0.05), IL12p35 (P < 0.05), and TNF (P < 0.05). In patients with UC, CD103 DCs show the impaired ability to generate Treg cells, but exhibit a colitogenic function inducing Th1/Th2/Th17 responses. These findings show how human CD103 DCs could contribute to the pathogenesis of UC.

Hypersensitivity pneumonitis onset and severity is regulated by CD103 dendritic cell expression.

BackgroundPulmonary dendritic cells drive lung responses to foreign antigens, including Saccharopolyspora rectivirgula, a causative agent of hypersensitivity pneumonitis. While the airway inflammatory mechanisms involved in hypersensitivity pneumonitis are well described, the mechanisms leading to the break in homeostasis and hypersensitivity pneumonitis onset are not well-described, and could involve CD103+ dendritic cells, which are found at baseline and during inflammatory responses in the lung. However, recent demonstration of the ability of CD103+ dendritic cells to induce inflammatory responses starkly contrasts with their classically described role as regulatory cells. These discrepancies may be attributable to the lack of current information on the importance of CD103 expression and modulation on these cells during inflammatory episodes.MethodsTo verify the importance of CD103 expression in the regulation of hypersensitivity pneumonitis, wild-type and Cd103-/- mice were exposed intranasally to S. rectivirgula and airway inflammation was quantified. Surface expression of CD103 in response to S. rectivirgula exposure was studied and cell transfers were used to determine the relative importance of CD103 expression on dendritic cells and T cells in regulating the inflammation in hypersensitivity pneumonitis.ResultsCd103-/- mice developed an exacerbated inflammatory response as early as 18h following S. rectivirgula exposure. CD103 expression on dendritic cells was downregulated quickly following S. rectivirgula exposure, and cell transfers demonstrated that CD103 expression on dendritic cells specifically (and not T cells) regulates the onset and severity of this response.ConclusionAll in all, we demonstrate that CD103 expression by dendritic cells, but not T cells, is crucial for homeostasis maintenance and the regulation of the TH17 airway inflammatory response in hypersensitivity pneumonitis.

Male microbiota-associated metabolite protects female BWF1 mice from lupus possibly by restoring tolerogenic CD103+ DC function.

Abstract Alterations in microbiota composition are associated with autoimmune diseases. We have found previously that microbiota composition differs significantly between female and male BWF1 mice, and transfer of male microbiota to females suppresses disease and increases survival. Protection appears to be mediated, at least in part, through male microbiota action on CD103+ dendritic cells (CD103DC) that induce Tregs in the periphery (pTregs). Female BWF1 CD103DC appear to have a defect in their ability to synthesize retinoic acid (RA; critical for Treg conversion and synthesis requires retinaldehyde dehydrogenase, RALDH2, activity) that is restored by male microbiota transfer. How the male microbiota protects against disease is unknown, but may be mediated through differential production of metabolites. We have performed multiple metabolomic analyses on feces from female and male BWF1 mice and from female recipients of male microbiota. We have identified &amp;gt;90 metabolites that are differentially produced, including those that can act as HDAC inhibitors, fatty acid synthesis inhibitors, and retinoid X receptor agonists (i.e., may enhance RALDH2 activity). We found that feeding the male microbial metabolite with RXR agonist activity to female BWF1 mice significantly increased CD103DC RALDH2 activity and the levels of pTregs in vivo, and delayed the onset of kidney disease. Taken together, these data suggest that at least one male microbiota-associated metabolite may be capable of suppressing disease directly, and may do so by enhancing tolerogenic CD103DC activity. Experiments are currently underway to test the effect of other male microbial metabolites on the immune mechanisms involved in lupus.

Abstract 592: Constitutive CD40-Signaling in Dendritic Cells Limits Atherosclerosis by Provoking Inflammatory Bowel Disease and Ensuing Cholesterol Malabsorption

The co-stimulatory molecule CD40 is a major driver of atherosclerosis. It is expressed on a wide variety of cell types including mature dendritic cells (DCs) and required for optimal T cell activation and expansion. It remains undetermined if and how CD40 on DCs impacts the pathogenesis of atherosclerosis. Here we examined the effects of constitutively active CD40 in DCs on atherosclerosis, using low-density lipoprotein-deficient (Ldlr -/- ) bone-marrow chimeras that express an engineered latent membrane protein 1 (LMP)/CD40 fusion protein conferring constitutive CD40 signaling under control of the CD11c promoter ( DC-CD40ca ). As expected, DC-CD40ca/Ldlr -/- chimeras showed increased antigen presenting capacity on DCs and increased T cell numbers. However, they developed extensive neutrophilia compared to wt / ldlr -/- chimeras. Despite overt T cell expansion and neutrophilia we observed a reduction in cDC frequency and a dramatic reduction in atherosclerosis ( CD40wt/ldlr -/- 22076±3763 μm 2 vs. DC-CD40ca/ldlr -/- 2511±1256 μm 2 ). Further analyses revealed that cholesterol and triglyceride levels decreased by 37% and 60%, respectively, in DC-CD40ca/Ldlr -/- chimeras. Moreover, DC-CD40ca/Ldlr -/- chimeras developed inflammatory bowel disease characterized by massive transmural influx of leukocytes and lymphocytes, resulting in villous degeneration and lipid malabsorption. Constitutive activation of CD40 in DCs results in inflammation of the gastrointestinal tract, thereby impairing lipid uptake, which consequently results in attenuated atherosclerosis.

215 - Defects in CD103 Dendritic Cell Migration Post Bone Marrow Transplantation is Responsible for the Reduction of Th1 Response to Gammaherpesvirus Infection

215 - Defects in CD103 Dendritic Cell Migration Post Bone Marrow Transplantation is Responsible for the Reduction of Th1 Response to Gammaherpesvirus Infection

Influence of Platelet-rich Plasma on the immune response of human monocyte-derived dendritic cells and macrophages stimulated with Aspergillus fumigatus

Dendritic cells (DCs) and macrophages (MΦ) are critical for protection against pathogenic fungi including Aspergillus fumigatus. To analyze the role of platelets in the innate immune response, human DCs and MΦs were challenged with A. fumigatus in presence or absence of human platelet rich plasma (PRP). Gene expression analyses and functional investigations were performed. A systems biological approach was used for initial modelling of the DC – A. fumigatus interaction. DCs in a quiescent state together with different corresponding activation states were validated using gene expression data from DCs and MΦ stimulated with A. fumigatus.To characterize the influence of platelets on the immune response of DCs and MΦ to A. fumigatus, we experimentally quantified their cytokine secretion, phagocytic capacity, maturation, and metabolic activity with or without platelets. PRP in combination with A. fumigatus treatment resulted in the highest expression of the maturation markers CD80, CD83 and CD86 in DCs. Furthermore, PRP enhanced the capacity of macrophages and DCs to phagocytose A. fumigatus conidia. In parallel, PRP in combination with the innate immune cells significantly reduced the metabolic activity of the fungus. Interestingly, A. fumigatus and PRP stimulated MΦ showed a significantly reduced gene expression and secretion of IL6 while PRP only reduced the IL-6 secretion of A. fumigatus stimulated DCs.The in silico systems biological model correlated well with these experimental data. Different modules centrally involved in DC function became clearly apparent, including DC maturation, cytokine response and apoptosis pathways. Taken together, the ability of PRP to suppress IL-6 release of human DCs might prevent local excessive inflammatory hemorrhage, tissue infarction and necrosis in the human lung.

Effects of beta-tricalcium phosphate particles on primary cultured murine dendritic cells and macrophages

Beta-tricalcium phosphate (β-TCP) is widely used for bone substitution in clinical practice. Particles of calcium phosphate ceramics including β-TCP act as an inflammation mediators, which is an unfavorable characteristic for a bone substituent or a prosthetic coating material. It is thought that the stimulatory effect of β-TCP on the immune system could be utilized as an immunomodulator.Here, in vitro effects of β-TCP on primary cultured murine dendritic cells (DCs) and macrophages were investigated. β-TCP particles enhanced expression of costimulatory surface molecules, including CD86, CD80, and CD40 in DCs, CD86 in macrophages, and MHC class II and class I molecules in DCs. DEC205 and CCR7 were up-regulated in β-TCP-treated DCs. Production of cytokines and chemokines, including CCL2, CCL3, CXCL2, and M-CSF, significantly increased in DCs; CCL2, CCL3, CCL4, CCL5, CXCL2, and IL-11ra were up-regulated in macrophages. The results of the functional assays revealed that β-TCP caused a prominent reduction in antigen uptake by DCs, and that conditioned medium from DCs treated with β-TCP facilitated the migration of splenocytes in the transwell migration assay. Thus, β-TCP induced phenotypical and functional maturation/activation of DCs and macrophages; these stimulating effects may contribute to the observed in vivo effect where β-TCP induced extensive migration of immune cells. When compared to lipopolysaccharide (LPS), an authentic TLR ligand, the stimulatory effect of β-TCP on the immune systems is mild to moderate; however, it may have some advantages as a novel immunomodulator. This is the first report on the direct in vitro effects of β-TCP against bone marrow-derived DCs and macrophages.

Evaluation of various adjuvant nanoparticulate formulations for meningococcal capsular polysaccharide-based vaccine

Neisseria meningitidis is a leading cause of bacterial meningitis and sepsis and its capsular polysaccharides (CPS) are a major virulence factor in meningococcal infections and form the basis for serogroup designation and preventive vaccines. We have formulated a novel meningococcal nanoparticulate vaccine formulation that does not require chemical conjugation, but encapsulates meningococcal CPS polymers in a biodegradable material that slowly release antigens, thereby has antigen depot effect to enhance antigenicity. The novel vaccine formulation is inexpensive and can be stored as a dry powder with extended shelf life that does not require the cold-chain which facilitates storage and distribution. In order to enhance the antigenicity of meningococcal nanoparticulate vaccine, we screened various adjuvants formulated in nanoparticles, for their ability to potentiate antigen presentation by dendritic cells. Here, we report that MF59 and Alum are superior to TLR-based adjuvants in enhancing dendritic cell maturation and antigen presentation markers MHC I, MHC II, CD40, CD80 and CD86 in dendritic cells pulsed with meningococcal CPS nanoparticulate vaccine.

Tu1843 Mucosa-Associated CD103 Dendritic Cells Are Targets of Hedgehog Signaling

Tu1843 Mucosa-Associated CD103 Dendritic Cells Are Targets of Hedgehog Signaling