Different Types Of Dendritic Cells Research Articles

TLR9-Dependent Activation by Inactivated Parapoxvirus Ovis in Murine Bone Marrow-Derived Dendritic Cells Is Associated with Specific Strain-Dependent Dendritic Cell Subsets

Introduction: Inactivated parapoxvirus ovis (iPPVO) exerts strong immunomodulatory effects on innate immune cells, making it an attractive therapeutic candidate. However, little is known about the signaling pathways that are involved in iPPVO-induced immune responses. Methods: In this study, we systematically analyzed how different types of dendritic cells (DCs) react to iPPVO (Zylexis, strain D1701) in both BALB/c and C57BL/6 mice by flow cytometry and ELISAs, and investigated which signaling pathway is related to DC activation by Western blotting and protein profiling. Results: We demonstrated that bone marrow-derived conventional DCs (BM-cDCs) and bone marrow-derived plasmacytoid DCs (BM-pDCs) matured and secreted type I interferons in response to Zylexis stimulation in both mouse strains. Similarly, Zylexis promoted the secretion of IL-12/23p40 and TNF by pDCs. However, IL-12/23p40 and TNF secretion by cDCs were induced in BALB/c mice but not in C57BL/6 mice. Analyzing the underlying signaling pathways revealed that iPPVO-induced maturation of cDCs was Toll-like receptor 9 (TLR9) independent, while the maturation of pDCs partially depended on the TLR9 pathway. Moreover, the production of proinflammatory cytokines by cDCs and the secretion of IFN-α/β by pDCs partially depended on the TLR9 pathway in both mouse strains. Therefore, other signaling pathways seem to participate in the response of DCs to iPPVO, supported by protein profiling. Conclusion: Our data provide useful insights into the diversity of iPPVO sensors and their varying effects across different strains and species.

Myelin Oligodendrocyte Glycoprotein (MOG)35-55 Mannan Conjugate Induces Human T-Cell Tolerance and Can Be Used as a Personalized Therapy for Multiple Sclerosis.

We have previously performed preclinical studies with the oxidized mannan-conjugated peptide MOG35-55 (OM-MOG35-55) in vivo (EAE mouse model) and in vitro (human peripheral blood) and demonstrated that OM-MOG35-55 suppresses antigen-specific T cell responses associated with autoimmune demyelination. Based on these results, we developed different types of dendritic cells (DCs) from the peripheral blood monocytes of patients with multiple sclerosis (MS) or healthy controls presenting OM-MOG35-55 or MOG-35-55 to autologous T cells to investigate the tolerogenic potential of OM-MOG35-55 for its possible use in MS therapy. To this end, monocytes were differentiated into different DC types in the presence of IL-4+GM-CSF ± dexamethasone (DEXA) ± vitamin D3 (VITD3). At the end of their differentiation, the DCs were loaded with peptides and co-cultured with T cells +IL-2 for 4 antigen presentation cycles. The phenotypes of the DC and T cell populations were analyzed using flow cytometry and the secreted cytokines using flow cytometry or ELISA. On day 8, the monocytes had converted into DCs expressing the typical markers of mature or immature phenotypes. Co-culture of T cells with all DC types for 4 antigen presentation cycles resulted in an increase in memory CD4+ T cells compared to memory CD8+ T cells and a suppressive shift in secreted cytokines, mainly due to increased TGF-β1 levels. The best tolerogenic effect was obtained when patient CD4+ T cells were co-cultured with VITD3-DCs presenting OM-MOG35-55, resulting in the highest levels of CD4+PD-1+ T cells and CD4+CD25+Foxp3+ Τ cells. In conclusion, the tolerance induction protocols presented in this work demonstrate that OM-MOG35-55 could form the basis for the development of personalized therapeutic vaccines or immunomodulatory treatments for MS.

Dendritic cell-based immunotherapy in non-small cell lung cancer: a comprehensive critical review.

Despite treatment advances through immunotherapies, including anti-PD-1/PD-L1 therapies, the overall prognosis of non-small cell lung cancer (NSCLC) patients remains poor, underscoring the need for novel approaches that offer long-term clinical benefit. This review examined the literature on the subject over the past 20 years to provide an update on the evolving landscape of dendritic cell-based immunotherapy to treat NSCLC, highlighting the crucial role of dendritic cells (DCs) in immune response initiation and regulation. These cells encompass heterogeneous subsets like cDC1s, cDC2s, and pDCs, capable of shaping antigen presentation and influencing T cell activation through the balance between the Th1, Th2, and Th17 profiles and the activation of regulatory T lymphocytes (Treg). The intricate interaction between DC subsets and the high density of intratumoral mature DCs shapes tumor-specific immune responses and impacts therapeutic outcomes. DC-based immunotherapy shows promise in overcoming immune resistance in NSCLC treatment. This article review provides an update on key clinical trial results, forming the basis for future studies to characterize the role of different types of DCs in situ and in combination with different therapies, including DC vaccines.

Expression of VAChT and 5-HT in Ulcerative colitis dendritic cells

Ulcerative colitis is a chronic inflammatory condition of the gastrointestinal tract that can affect people of worldwide. In contrast with Crohn’s disease, that can relate the entire thickness of the bowel wall, the inflammation of ulcerative colitis is limited to the colonic mucosa. Immune cells including activated T cells, plasma cells, mast cells, macrophages, and dendritic cells (DCs) trigger the inflammation. Furthermore, dendritic cells are antigen presenting cells involved in maintaining intestinal immune homeostasis. It has been described an increment of number in DCs colonic mucosa of patients with ulcerative colitis. The immune cells such as antigen-presenting cells can act as autocrine or paracrine modulators. Recent studies showed that dendritic cells synthetized and released classical neurotransmitters as glutamate, dopamine, acetylcholine, and serotonin. Paraformaldehyde-fixed intestinal tissues, obtained from the stricture sites of ten patients with ulcerative colitis were analyzed by immunostaining for Langerin/CD207, serotonin and vesicular acetylcholine transporter. As controls, unaffected (normal) portions of five patients were also investigated. Aim of this study was to characterize for the first time the human gut dendritic cells of ulcerative colitis patients, with Langerin/CD207 that is a c-type lectin expressed by different types of DCs and to colocalize in the same cells the expression of serotonin and vesicular acetylcholine transporter, showing the link between dendritic cells, gut enterochromaffin cells or autonomic nerves in immune activation and generation of intestinal inflammation.

Antigen-Presenting Cells in Food Tolerance and Allergy.

Food allergy now affects 6%–8% of children in the Western world; despite this, we understand little about why certain people become sensitized to food allergens. The dominant form of food allergy is mediated by food-specific immunoglobulin E (IgE) antibodies, which can cause a variety of symptoms, including life-threatening anaphylaxis. A central step in this immune response to food antigens that differentiates tolerance from allergy is the initial priming of T cells by antigen-presenting cells (APCs), primarily different types of dendritic cells (DCs). DCs, along with monocyte and macrophage populations, dictate oral tolerance versus allergy by shaping the T cell and subsequent B cell antibody response. A growing body of literature has shed light on the conditions under which antigen presentation occurs and how different types of T cell responses are induced by different APCs. We will review APC subsets in the gut and discuss mechanisms of APC-induced oral tolerance versus allergy to food identified using mouse models and patient samples.

Dual Pro- and Anti-Inflammatory Features of Monocyte-Derived Dendritic Cells.

The transcription factor β-catenin is able to induce tolerogenic/anti-inflammatory features in different types of dendritic cells (DCs). Monocyte-derived dendritic cells (moDCs) have been widely used in dendritic cell-based cancer therapy, but so far with limited clinical efficacy. We wanted to investigate the hypothesis that aberrant differentiation or induction of dual pro- and anti-inflammatory features may be β-catenin dependent in moDCs. β-catenin was detectable in both immature and lipopolysaccharide (LPS)-stimulated DCs. The β-catenin inhibitor ICG-001 dose-dependently increased the pro-inflammatory signature cytokine IL-12p70 and decreased the anti-inflammatory signature molecule IL-10. The β-catenin activator 6-bromoindirubin-3′-oxime (6-BIO) dose-dependently increased total and nuclear β-catenin, and this was associated with decreased IL-12p70, increased IL-10, and reduced surface expression of activation markers, such as CD80 and CD86, and increased expression of inhibitory markers, such as PD-L1. 6-BIO and ICG-001 competed dose-dependently regarding these features. Genome-wide mRNA expression analyses further underscored the dual development of pro- and anti-inflammatory features of LPS-matured moDCs and suggest a role for β-catenin inhibition in production of more potent therapeutic moDCs.

THE ROLE OF INTRATUMORAL DENDRITIC CELLS IN THE PROGRESSION OF SQUAMOUS CELL CARCINOMAS

The aim of the studywas to summarize data on the role of tumor-associated dendritic cells (DC) in the formation of squamous cell carcinoma microenvironment, their participation in the development of immune inflammatory responses in the tumor stroma and relation to tumor progression.Material and Methods. We analyzed 79 publications available from Pubmed, Google Scholar, Elibrary databases from January 2000 to December 2017.Results. The characteristics of different types of DC, including Langerhans cells (CR), were presented. The different methods of DC identification were described. The information on the presence of DC in squamous cell carcinomas was analyzed. The influence of the tumor on DCs, as well as the relationship between the number and functional characteristics of DCs and invasive/metastatic tumor potentialities was described. The prognostic value of DCs and their effect on disease-free, metastasis-free and overall survival rates were analyzed. The data on the association between DCs and the response to chemoradiotherapy were presented. The analysis of the relationship between the DC characteristics and the development of immuno-inflammatory responses in the tumor microenvironment was carried out.Conclusion. The methodological approaches to the detection of DCs are variable, but the sensitivity of each method, as well as the comparison of different methods for estimating the number and functional characteristics of DCs, have been little studied. There is no data on the relationship between the length of DC dendrites and the parameters of invasive/metastatic tumor potentialities, disease-free, metastasis-free and overall survival rates. Numerous studies indicate the association between the number of DCs and the tumor progression, however these data are contradictory. There is no data about the relationship between the number of DCs and hematogenous metastasis of squamous cell carcinomas. The association of tumor-associated DC with the types of immunoinflammatory responses in the tumor microenvironment has been insufficiently studied.

Decreased regulatory T cells in vulnerable atherosclerotic lesions: imbalance between pro- and anti-inflammatory cells in atherosclerosis.

Atherosclerosis is a chronic inflammatory disease of the arterial wall in which presentation of autoantigens by dendritic cells (DCs) leads to the activation of T cells. Anti-inflammatory cells like Tregs counterbalance inflammation in atherogenesis. In our study, human carotid plaque specimens were classified as stable (14) and unstable (15) according to established morphological criteria. Vessel specimens (n = 12) without any signs of atherosclerosis were used as controls. Immunohistochemical staining was performed to detect different types of DCs (S100, fascin, CD83, CD209, CD304, and CD123), proinflammatory T cells (CD3, CD4, CD8, and CD161), and anti-inflammatory Tregs (FoxP3). The following results were observed: in unstable lesions, significantly higher numbers of proinflammatory cells like DCs, T helper cells, cytotoxic T cells, and natural killer cells were detected compared to stable plaques. Additionally, there was a significantly higher expression of HLA-DR and more T cell activation (CD25, CD69) in unstable lesions. On the contrary, unstable lesions contained significantly lower numbers of Tregs. Furthermore, a significant inverse correlation between myeloid DCs and Tregs was shown. These data suggest an increased inflammatory state in vulnerable plaques resulting from an imbalance of the frequency of local pro- and anti-inflammatory immune cells.

Human dendritic cell differentiation from monocytes

Dendritic cells (DCs) induce, sustain, and regulate immune responses and are essential mediators of immunity and tolerance. These cells are specialized to capture antigens, process and present them to T cells to initiate immune responses towards pathogens and tumours. DCs are heterogeneous for origin, anatomical localization, phenotype and function. They differentiate from haematopoietic stem cells-derived precursors, migrate from sites of antigen uptake to lymphoid organs, mature and interact with lymphocytes. Langerhans cells (LCs) are immature DCs, are located in stratified squamous epithelia of the epidermis and mucosae. LCs express CD1a, langerin/ CD207, E-cadherin and have intracytoplasmic Birbeck granules. We wonder if the PPAR (peroxisome proliferator activated receptor)-gamma stimulation can give rise to LCs in vitro starting from CD14+ monocytes, as occurs with CD133+ haematopoietic precursors (1). Circulating CD14+ monocytes have been isolated by immunomagnetic separation and cultured with GM-CSF, IL-4, TNF-α and TGF-β for 7 days. The complete maturation was induced by further culture for 48 h with the same cytokines, but the concentration of the TGF-β was increased (2). Rosiglitazone was used to stimulate PPAR-γ from the start of the culture. The cells were analysed by phase contrast, electron microscopy, immunofluorescence, flow cytometry and mixed lymphocyte reaction. All cultures generated mature cells that expressed MHCII intensely, both with and without rosiglitazone, and had lymphocyte stimulating activity. The obtained DCs express the DC-SIGN, such as connective tissue DCs, more intensely with than without rosiglitazone. Some of these cells were CD1a+ and among them a small part was CD207+, i.e. they were LC-like, however they never contained Birbeck granules. The percentages of cells CD1a+ and CD207+ were slightly higher without rosiglitazone. The results indicate that upon addition of rosiglitazone the in vitro differentiation of monocytes to LCs is hampered, at variance with what happens with cultures of CD133+ precursors. For this reason, experiments have been planned with CD34+ haematopoietic stem cells, because the generation of different types of DCs is a necessary step to gain control on these cells for medical purposes.

Dendritic Cell-Based Approaches in the Fight Against Diseases

DENDRITIC CELL ROLE IN THE IMMUNE SYSTEM AND ITS MANIPULATION The immune system works to contain infections through activation of different molecules and cell types. Correct presentation of antigens by antigen-presenting cells (APCs) is a critical step necessary to initiate an immune response. APCs have the ability to take-up and process antigens, and express high levels of co-stimulatory and major histocompatibility complex (MHC) molecules bound to antigens (1). Dendritic cells (DCs) are innate immune cells first characterized and reported by Ralph Steinman in 1973 (2). For their unique properties and features, DCs are the most important APCs acting at the interface of innate and adaptive immunity, which results in the activation of immune responses in the body. Distinct subsets of DCs are associated with lineage and receptor expression patterns (3). Dendritic cells have different roles in the immune system, such as activation and regulation of adaptive immune responses, and other opposing functions in the induction of tolerance and anergy (4). During immune responses, DCs are crucial decision makers toward the development of naive T cells to T helper type 1 (Th1) or type (Th2) profile (5). Among the different families of molecules expressed by DC to aid in their function, one of them is the family of toll-like receptors (TLR). TLR which are expressed by different types of DCs, and bind to common molecules associated with pathogens. Once bound, molecules such as bacterial lipopolysaccharide and hypomethylated CpG DNA, can induce activation of biochemical cell pathways, resulting in overexpression of MHC, co-stimulatory molecules (CD80, CD86), and cytokines (6). In this context, a number of methods have been available to manipulate DCs from diverse sites in the body resulting in activated cells for therapy. These methods include reinfusion of unloaded DCs; reinfusion of DCs co-cultured with peptides or proteins of interest; in vivo DC loading; DC transfection with antigen-encoding viruses or nucleic acids; and DC-derived exosomes (7, 8). After this, DCs might be ready to promote protection or treat specific diseases. In this context, the availability of methods to manipulate DCs in laboratory, arise as an important tool for immunointerventions in different diseases. In this opinion article, we focused on the basis of DC approaches already available in the field of cancer currently in test for infectious diseases, and future interventions that are needed.

SAT0067 Mice lacking FLT3L are protected from collagen-induced arthritis: Regulating the regulators

BackgroundAutoimmune diseases often result from inappropriate or unregulated activation of autoreactive T cells. Traditional approaches to treat autoimmune diseases have focused on direct inhibition of autoreactive T cells. A key...

Mice lacking Flt3L are protected from collagen-induced arthritis: impaired T cell function?

Backgroundand objectivesAutoimmune diseases often result from inappropriate or unregulated activation of autoreactive T cells. The induction and maintenance of T cell tolerance to tissue antigens is essential to prevent autoimmunity....

Dendritic cells in infectious disease, hypersensitivity, and autoimmunity

Dendritic cells are thought to direct subsequent T lymphocyte-driven adaptive immune responses (Th1/Th2) following interaction with either endogenous or exogenous antigens. These cells have an integral role in the pathogenesis of countless infectious diseases, but their role is most vividly illustrated in human immunodeficiency virus/acquired immunodeficiency syndrome and tuberculosis. Dendritic cells can arise from either myeloid or lymphoid progenitors, but the former is more common. Of particular importance are myeloid-related dendritic cells, plasmacytoid dendritic cells, infiltrating inflammatory dendritic epidermal cells, and Langerhans cells. Myeloid-related dendritic cells resemble typical monocytes, but produce cytokines that favor the cell-mediated immune response. Plasmacytoid dendritic cells resemble plasma cells, but have additional antigen-processing capabilities, and their major role is to produce interferon alpha and beta in response to viral infections. Inflammatory dendritic epidermal cells express the highest concentration of costimulatory molecules known in any cell lineage. Langerhans cells are the chief dendritic cells of the skin, and play a pivotal role in hypersensitivity and autoimmune patholo- gies, such as atopic dermatitis and psoriasis. Lastly, reduced glutathione has been implicated in modulation of the cytokine profiles of professional antigen-presenting cells, and holds promise as a future immunotherapeutic agent. This review discusses in detail the origin, characteristics, and overall functions of different types of dendritic cells. Furthermore, we have also highlighted the role of dendritic cells in infectious diseases and autoimmune diseases, with special reference to human immunodeficiency virus, tuberculosis, atopic dermatitis, and psoriasis.

Regulation of CXCL16 expression and secretion by myeloid cells is not altered in rheumatoid arthritis

Objective:Chemokine (C-X-C motif) ligand 16 (CXCL16) is secreted by macrophages and dendritic cells (DCs) to attract memory type T cells. CXCL16 expression is increased in arthritic joints of patients with...

Interactions between osteosarcoma cell lines and dendritic cells immune function: An in vitro study

Dendritic cells (DCs) might be partly responsible for the defective immune response in tumor bearing hosts, but no study in osteosarcoma patients is still available. Therefore, we investigated in vitro whether human osteosarcoma cell lines have an inhibitor effect on different types of DCs: CD14+DCs, DC1 and DC2. DCs derived from healthy donors were cultured with osteosarcoma cell lines and appropriate cytokine cocktails and analysed for the expression of co-stimulatory molecules (CD40, CD80, CD83, CD86, HLA-DR). Each interaction resulted in a lower phenotypic expression of the DCs maturation markers, especially on DC2. Moreover, the addition of various cytokines and compounds (rhIL-12, CD40L, Indometacin) induced the DC1 and DC2 subsets towards the Th1 pattern as shown by ELISA. Osteosarcoma highly interferes with an in vitro DCs immune function as antigen presenting cells. The understanding of tumor biology underlines the need for a specific osteosarcoma immunotherapy able to reverse this immune-surveillance inhibition.

Steady-state and inflammatory dendritic-cell development

The developmental pathways that lead to the production of antigen-presenting dendritic cells (DCs) are beginning to be understood. These are the last of the pathways of haematopoiesis to be mapped. The existence of many specialized subtypes of DC has complicated this endeavour, as has the need to distinguish the DCs formed in steady state from those produced during an inflammatory response. Here we review studies that lead to the concept that different types of DC develop through different branches of haematopoietic pathways that involve different immediate precursor cells. Furthermore, these studies show that many individual tissues generate their own DCs locally, from a reservoir of immediate DC precursors, rather than depending on a continuous flux of DCs from the bone marrow.

International meeting "Immunotherapy of cancer: challenges and needs".

The main aims of the international meeting "Immunotherapy of Cancer: Challenges and Needs" were to review the state of the art of cancer immunotherapy and to identify critical issues which deserve special attention for promoting progress of research in this field, with a particular focus on the perspectives of clinical research. Novel concepts and strategies for identifying, monitoring and predicting effective responses to cancer immunotherapy protocols were presented, focused on the use of adjuvants (CpG oligonucleotides) or cytokines (IFN-alpha) to enhance the efficacy of cancer vaccines. Moreover, the possible advantages of using different types of dendritic cells (for active immunization strategies) or T cells (for adoptive immunotherapy protocols) were debated. A consensus was achieved on the need for enhancing the efficacy of cancer vaccines or adoptive cell immunotherapy by combining these strategies with other anti-cancer treatments, including chemotherapy. Finally, initiatives for promoting clinical research by establishing a strategic cooperation in the field of cancer immunotherapy based on the active participation of all the relevant actors, including public institutions responsible of Public Health, National Cancer Institutes, industry, representatives of regulatory bodies, and patients' organizations were proposed.

Dynamics of Dendritic Cell Phenotype and Interactions with CD4+ T Cells in Airway Inflammation and Tolerance

An emerging concept is that different types of dendritic cells (DCs) initiate different immune outcomes, such as tolerance vs inflammation. In this study, we have characterized the DCs from the lung draining lymph nodes of mice immunized for allergic airway inflammation or tolerance and examined their interactions with CD4(+) T cells. The DC population derived from tolerized mice was predominantly CD11c(+), B220(+), Gr-1(+), CD11b(-), and MHC class II(low), which resembled plasmacytoid-type DCs whereas DCs from the inflammatory condition were largely CD11c(+), B220(-), Gr-1(-), CD11b(+), and MHC class II(high) resembling myeloid-type DCs. The DCs from the tolerogenic condition were poor inducers of T cell proliferation. DCs from both conditions induced T cell IL-4 production but the T cells cultured with tolerogenic DCs were unresponsive to IL-4 as indicated by inhibition of STAT6 activation and expression of growth factor-independent 1, which has been recently shown to be important for STAT6-activated Th2 cell expansion. Our data suggest that airway tolerance vs inflammation is determined by the DC phenotype in lung draining lymph nodes.

Immunity toAspergillus fumigatus: the basis for immunotherapy and vaccination

Efficient responses to fungi require different mechanisms of immunity. Dendritic cells (DCs) are uniquely able to decode the fungus-associated information and translate it into qualitatively different T helper (Th) immune responses. Murine and human DCs phagocytose conidia and hyphae of Aspergillus fumigatus through distinct recognition receptors. The engagement of distinct receptors translates into disparate downstream signaling events, ultimately affecting cytokine production and co-stimulation. Adoptive transfer of different types of DCs activates protective and non-protective Th cells as well as regulatory T cells, ultimately affecting the outcome of the infection in mice with invasive aspergillosis. The infusion of fungus-pulsed or RNA-transfected DCs also accelerates recovery of functional antifungal Th 1 responses in mice with allogeneic hematopoietic stem cell transplantation. Patients receiving T cell-depleted allogeneic hematopoietic stem cell transplantation are unable to develop antigen-specific T cell responses soon after transplant due to defective DC functions. Our results suggest that the adoptive transfer of DCs may restore immunocompetence in hematopoietic stem cell transplantation by contributing to the educational program of T cells. Thus, the remarkable furictional plasticity of DCs can be exploited for the deliberate targeting of cells and pathways of cell-mediated immunity in response to the fungus.

Dendritic cell-based vaccination against opportunistic fungi

Efficient responses to the different forms of fungi require different mechanisms of immunity. Dendritic cells (DCs) are uniquely able to decode the fungus-associated information and translate it in qualitatively different T helper (Th) immune responses, in vitro and in vivo. DCs sense fungi in a morphotype-specific manner, through the engagement of distinct recognition receptors ultimately affecting cytokine production and costimulation. Adoptive transfer of different types of DCs activates protective and non-protective Th cells as well as regulatory T cells and affects the outcome of the infections. DCs transfected with fungal RNA also restore antifungal resistance in hematopoietic transplantation. Thus, the remarkable functional plasticity of DCs in response to fungi can be exploited for the deliberate targeting of cells and pathways of cell-mediated immunity in response to fungal vaccines.