Dendritic Cells Subsets Research Articles

Mass Cytometry Reveals the Imbalanced Immune State in the Peripheral Blood of Patients with Essential Hypertension.

Mounting evidence has confirmed that essential hypertension (EH) is closely related to low-grade inflammation, but there is still a lack of in-depth understanding of the state of immune cells in the circulating blood of patients with EH. We analyzed whether hypertensive peripheral blood immune cell balance was destroyed. The peripheral blood mononuclear cells (PBMCs) of all subjects were analyzed using time-of-flight cytometry (CyTOF) based on 42 kinds of metal-binding antibodies. CD45+ cells were categorized into 32 kinds of subsets. Compared with the health control (HC) group, the percentage of total dendritic cells, two kinds of myeloid dendritic cell subsets, one intermediate/nonclassical monocyte subset and one CD4+ central memory T cell subset in the EH group, was significantly higher; the percentage of low-density neutrophils, four kinds of classical monocyte subsets, one CD14lowCD16- monocyte subset, one naive CD4+ and one naive CD8+ T cell subsets, one CD4+ effector and one CD4+ central memory T cell subsets, one CD8+ effector memory T cell subset, and one terminally differentiated γδ T cell subset, decreased significantly in EH. What is more, the expression of many important antigens was enhanced in CD45+ immune cells, granulocytes, and B cells in patients with EH. In conclusion, the altered number and antigen expression of immune cells reflect the imbalanced immune state of the peripheral blood in patients with EH.

The melanoma tumor glyco-code impacts human dendritic cells' functionality and dictates clinical outcomes.

Subversion of immunity is a hallmark of cancer development. Dendritic cells (DCs) are strategic immune cells triggering anti-tumor immune responses, but tumor cells exploit their versatility to subvert their functions. Tumor cells harbor unusual glycosylation patterns, which can be sensed through glycan-binding receptors (lectins) expressed by immune cells that are crucial for DCs to shape and orientate antitumor immunity. Yet, the global tumor glyco-code and its impact on immunity has not been explored in melanoma. To decrypt the potential link between aberrant glycosylation patterns and immune evasion in melanoma, we investigated the melanoma tumor glyco-code through the GLYcoPROFILE™ methodology (lectin arrays), and depicted its impact on patients' clinical outcome and DC subsets' functionality. Specific glycan patterns correlated with clinical outcome of melanoma patients, GlcNAc, NeuAc, TF-Ag and Fuc motifs being associated with poor outcome, whereas Man and Glc residues elicited better survival. Strikingly, tumor cells differentially impacting cytokine production by DCs harbored distinct glyco-profiles. GlcNAc exhibited a negative influence on cDC2s, whereas Fuc and Gal displayed inhibitory impacts on cDC1s and pDCs. We further identified potential booster glycans for cDC1s and pDCs. Targeting specific glycans on melanoma tumor cells restored DCs' functionality. The tumor glyco-code was also linked to the nature of the immune infiltrate. This study unveils the impact of melanoma glycan patterns on immunity, and paves the way for innovative therapeutic options. Glycans/lectins interactions arise as promising immune checkpoints to rescue DCs from tumor' hijacking to reshape antitumor immunity and inhibit immunosuppressive circuits triggered by aberrant tumor glycosylation.

Molecular Mechanisms Behind the Role of Plasmacytoid Dendritic Cells in Systemic Sclerosis

Systemic sclerosis (SSc) is a debilitating autoimmune disease that affects multiple systems. It is characterized by immunological deregulation, functional and structural abnormalities of small blood vessels, and fibrosis of the skin, and, in some cases, internal organs. Fibrosis has a devastating impact on a patient's life and lung fibrosis is associated with high morbimortality. Several immune populations contribute to the progression of SSc, and plasmacytoid dendritic cells (pDCs) have been identified as crucial mediators of fibrosis. Research on murine models of lung and skin fibrosis has shown that pDCs are essential in the development of fibrosis, and that removing pDCs improves fibrosis. pDCs are a subset of dendritic cells (DCs) that are specialized in anti-viral responses and are also involved in autoimmune diseases, such as SSc, systemic lupus erythematosus (SLE) and psoriasis, mostly due to their capacity to produce type I interferon (IFN). A type I IFN signature and high levels of CXCL4, both derived from pDCs, have been associated with poor prognosis in patients with SSc and are correlated with fibrosis. This review will examine the recent research on the molecular mechanisms through which pDCs impact SSc.

Spatial and molecular profiling of the mononuclear phagocyte network in classic Hodgkin lymphoma

AbstractClassic Hodgkin lymphoma (cHL) has a rich immune infiltrate, which is an intrinsic component of the neoplastic process. Malignant Hodgkin Reed-Sternberg cells (HRSCs) create an immunosuppressive microenvironment by the expression of regulatory molecules, preventing T-cell activation. It has also been demonstrated that mononuclear phagocytes (MNPs) in the vicinity of HRSCs express similar regulatory mechanisms in parallel, and their presence in tissue is associated with inferior patient outcomes. MNPs in cHL have hitherto been identified by a small number of canonical markers and are usually described as tumor-associated macrophages. The organization of MNP networks and interactions with HRSCs remains unexplored at high resolution. Here, we defined the global immune-cell composition of cHL and nonlymphoma lymph nodes, integrating data across single-cell RNA sequencing, spatial transcriptomics, and multiplexed immunofluorescence. We observed that MNPs comprise multiple subsets of monocytes, macrophages, and dendritic cells (DCs). Classical monocytes, macrophages and conventional DC2s were enriched in the vicinity of HRSCs, but plasmacytoid DCs and activated DCs were excluded. Unexpectedly, cDCs and monocytes expressed immunoregulatory checkpoints PD-L1, TIM-3, and the tryptophan-catabolizing protein IDO, at the same level as macrophages. Expression of these molecules increased with age. We also found that classical monocytes are important signaling hubs, potentially controlling the retention of cDC2 and ThExh via CCR1-, CCR4-, CCR5-, and CXCR3-dependent signaling. Enrichment of the cDC2-monocyte-macrophage network in diagnostic biopsies is associated with early treatment failure. These results reveal unanticipated complexity and spatial polarization within the MNP compartment, further demonstrating their potential roles in immune evasion by cHL.

Immunoregulation by antigen-presenting cells in human intestinal lamina propria.

Antigen-presenting cells, including macrophages and dendritic cells, are a type of innate immune cells that can induce the differentiation of T cells and activate the adaptive immune response. In recent years, diverse subsets of macrophages and dendritic cells have been identified in the intestinal lamina propria of mice and humans. These subsets contribute to the maintenance of intestinal tissue homeostasis by regulating the adaptive immune system and epithelial barrier function through interaction with intestinal bacteria. Further investigation of the roles of antigen-presenting cells localized in the intestinal tract may lead to the elucidation of inflammatory bowel disease pathology and the development of novel treatment approaches.

Human influenza virus infection elicits distinct patterns of monocyte and dendritic cell mobilization in blood and the nasopharynx.

During respiratory viral infections, the precise roles of monocytes and dendritic cells (DCs) in the nasopharynx in limiting infection and influencing disease severity are incompletely described. We studied circulating and nasopharyngeal monocytes and DCs in healthy controls (HCs) and in patients with mild to moderate infections (primarily influenza A virus [IAV]). As compared to HCs, patients with acute IAV infection displayed reduced DC but increased intermediate monocytes frequencies in blood, and an accumulation of most monocyte and DC subsets in the nasopharynx. IAV patients had more mature monocytes and DCs in the nasopharynx, and higher levels of TNFα, IL-6, and IFNα in plasma and the nasopharynx than HCs. In blood, monocytes were the most frequent cellular source of TNFα during IAV infection and remained responsive to additional stimulation with TLR7/8L. Immune responses in older patients skewed towards increased monocyte frequencies rather than DCs, suggesting a contributory role for monocytes in disease severity. In patients with other respiratory virus infections, we observed changes in monocyte and DC frequencies in the nasopharynx distinct from IAV patients, while differences in blood were more similar across infection groups. Using SomaScan, a high-throughput aptamer-based assay to study proteomic changes between patients and HCs, we found differential expression of innate immunity-related proteins in plasma and nasopharyngeal secretions of IAV and SARS-CoV-2 patients. Together, our findings demonstrate tissue-specific and pathogen-specific patterns of monocyte and DC function during human respiratory viral infections and highlight the importance of comparative investigations in blood and the nasopharynx.

Catching Our Breath: Updates on the Role of Dendritic Cell Subsets in Asthma.

Dendritic cells (DCs), as potent antigen presenting cells, are known to play a central role in the pathophysiology of asthma. The understanding of DC biology has evolved over the years to include multiple subsets of DCs with distinct functions in the initiation and maintenance of asthma. Furthermore, asthma is increasingly recognized as a heterogeneous disease with potentially diverse underlying mechanisms. The goal of this review is to summarize the role of DCs and the various subsets therein in the pathophysiology of asthma and highlight some of the crucial animal models shaping the field today. Potential future avenues of investigation to address existing gaps in knowledge are discussed.

P024 Effects of anti-TNF and anti-interleukins 12 and 23 drugs on circulating dendritic cells migratory capacity in inflammatory bowel disease

Abstract Background Inflammatory bowel disease (IBD) is an idiopathic and chronic disorder that includes ulcerative colitis (UC) and Crohn’s disease (CD). Both diseases are different but show an uncontrolled intestinal immune response that generates tissue inflammation. Dendritic cells (DC) are phagocytic professional antigen presenting cells that link the innate and adaptive immune systems. Indeed, they are the only cell type able to stimulate naïve T cells generating an antigen-specific immune response. In humans, DC can be divided into plasmacytoid (pDC) and c conventional type 1 and 2 (cDC1, cDC2). Although cDC migration towards the GI mucosa is enhanced in IBD, the mechanisms underlying these migrations and whether biological drugs can modulate them are currently unknown. This study aimed to analyze DC migratory capacity towards the GI mucosa, and whether biological drugs with different mechanisms of action can modulate this process in health and IBD. Methods This is a cross-sectional observational postmarketing study where the modulatory effect of different biological treatments on samples from patients with an endoscopic diagnosis of IBD and healthy controls was studied ex vivo. Peripheral blood mononuclear cells (PBMC) were obtained from 15 patients per group and were cultured in presence of golimumab or ustekinumab. Following culture, surface markers expression was determined, assessing the differential effect of biological drugs (if any) over the DC subsets in the different groups. After that, the migratory capacity of circulating DC towards CCL2, CCL25, and MadCam1 from the different study groups was determined. Finally, we evaluated the DC migratory capacities in presence of biological drugs or with culture media alone. Results The cCD2 subset showed higher expression levels of β7 and CCR5 compared to cCD1 (Figure 1). Golimumab and ustekinumab did not modify the expression of the homing markers in any studied subset (Figure 2). Even though no conclusive results were obtained for the biological drugs used in the study on the expression of homing markers, ustekinumab decreased the migratory capacity of cDC2 from CD patients towards a medium supplemented with CCL25 (Figure 3). Conclusion cDC2 showed more migratory profile markers than other DC populations. Golimumab and ustekinumab did not modify the expression of the homing markers in any DC subset in any group. Nevertheless, ustekinumab decreased the migratory capacity of cDC2 from CD patients. This fact indicates that the behavior of this population is different in CD and UC and that the migration capacity of this subset is not dependent on homing markers.

Single-cell RNA-seq analysis reveals dual sensing of HIV-1 in blood Axl+ dendritic cells

Sensing of incoming viruses is a pivotal task of dendritic cells (DCs). Human primary blood DCs encompass various subsets that are diverse in their susceptibility and response to HIV-1. The recent identification of the blood Axl+DC subset, endowed with unique capacities to bind, replicate, and transmit HIV-1 prompted us to evaluate its anti-viral response. We demonstrate that HIV-1 induced two main broad and intense transcriptional programs in different Axl+DCs potentially induced by different sensors; an NF-κB-mediated program that led to DC maturation and efficient CD4+ Tcell activation, and a program mediated by STAT1/2 that activated type I IFN and ISG responses. These responses were absent from cDC2 exposed to HIV-1 except when viral replication was allowed. Finally, Axl+DCs actively replicating HIV-1 identified by quantification of viral transcripts exhibited a mixed NF-κB/ISG innate response. Our results suggest that the route of HIV-1 entry may dictate different innate sensing pathways by DCs.

Differential expression of nuclear hormone receptors by dendritic cell subsets in human vaginal mucosa and skin.

Nuclear hormone receptors (NHRs) expressed by dendritic cells (DCs), the major immune inducers and regulators, could play important roles in host immunity. Assessment of NHRs expressed by DCs in the vaginal mucosa (VM), in comparison with those expressed by DCs in other tissues, will thus help us understand the immunology of human vagina. This study identified 16 NHR transcripts that are differentially expressed among 8 different antigen-presenting cell (APC) subsets isolated from human VM, skin, and blood. The expression profiles of NHRs were largely tissue specific. VM APCs expressed increased levels of LXRA, RXRA, ESRRA, ESRRAP2, and PPARG, whereas skin and blood APCs expressed increased levels of NURR1, NOR1 and RARA. Of interest, female sex hormone receptors, ESR1 and PGR, were found to be mainly expressed by non-APC cell types in the VM; ESR1 by HLA-DR+CD34+ and PGR by HLA-DR- cells. ERα and PR were expressed by vimentin+ cells in the VM, but not in human skin. ERα, but not PR, was also expressed in CD10+ cells in the lamina propria of VM. In conclusion, NHR expression by APC subsets is tissue- and cell type-specific. Future studies on the roles of individual NHRs expressed by different cell types, including DC subsets, in the human VM are warranted.

Perioperative corticosteroid treatment impairs tumor-infiltrating dendritic cells in patients with newly diagnosed adult-type diffuse gliomas.

Adult-type diffuse gliomas are malignant primary brain tumors characterized by very poor prognosis. Dendritic cells (DCs) are key in priming antitumor effector functions in cancer, but their role in gliomas remains poorly understood. In this study, we characterized tumor-infiltrating DCs (TIDCs) in adult patients with newly diagnosed diffuse gliomas by using multi-parametric flow cytometry and single-cell RNA sequencing. We demonstrated that different subsets of DCs are present in the glioma microenvironment, whereas they are absent in cancer-free brain parenchyma. The largest cluster of TIDCs was characterized by a transcriptomic profile suggestive of severe functional impairment. Patients undergoing perioperative corticosteroid treatment showed a significant reduction of conventional DC1s, the DC subset with key functions in antitumor immunity. They also showed phenotypic and transcriptional evidence of a more severe functional impairment of TIDCs. Overall, the results of this study indicate that functionally impaired DCs are recruited in the glioma microenvironment. They are severely affected by dexamethasone administration, suggesting that the detrimental effects of corticosteroids on DCs may represent one of the mechanisms contributing to the already reported negative prognostic impact of steroids on glioma patient survival.

Guidelines for visualization and analysis of DC in tissues using multiparameter fluorescence microscopy imaging methods.

This article is part of the Dendritic Cell Guidelines article series, which provides a collection of state-of-the-art protocols for the preparation, phenotype analysis by flow cytometry, generation, fluorescence microscopy, and functional characterization of mouse and human dendritic cells (DC) from lymphoid organs and various non-lymphoid tissues. Here, we provide detailed procedures for a variety of multiparameter fluorescence microscopy imaging methods to explore the spatial organization of DC in tissues and to dissect how DC migrate, communicate, and mediate their multiple functional roles in immunity in a variety of tissue settings. The protocols presented here entail approaches to study DC dynamics and T cell cross-talk by intravital microscopy, large-scale visualization, identification, and quantitative analysis of DC subsets and their functions by multiparameter fluorescence microscopy of fixed tissue sections, and an approach to study DC interactions with tissue cells in a 3D cell culture model. While all protocols were written by experienced scientists who routinely use them in their work, this article was also peer-reviewed by leading experts and approved by all co-authors, making it an essential resource for basic and clinical DC immunologists.

Major alterations to monocyte and dendritic cell subsets lasting more than 6 months after hospitalization for COVID-19.

After more than two years the Coronavirus disease-19 (COVID-19) pandemic continues to burden healthcare systems and economies worldwide, and it is evident that the effects on the immune system can persist for months post-infection. The activity of myeloid cells such as monocytes and dendritic cells (DC) is essential for correct mobilization of the innate and adaptive responses to a pathogen. Impaired levels and responses of monocytes and DC to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is likely to be a driving force behind the immune dysregulation that characterizes severe COVID-19. Here, we followed a cohort of COVID-19 patients hospitalized during the early waves of the pandemic for 6-7 months. The levels and phenotypes of circulating monocyte and DC subsets were assessed to determine both the early and long-term effects of the SARS-CoV-2 infection. We found increased monocyte levels that persisted for 6-7 months, mostly attributed to elevated levels of classical monocytes. Myeloid derived suppressor cells were also elevated over this period. While most DC subsets recovered from an initial decrease, we found elevated levels of cDC2/cDC3 at the 6-7 month timepoint. Analysis of functional markers on monocytes and DC revealed sustained reduction in program death ligand 1 (PD-L1) expression but increased CD86 expression across almost all cell types examined. Finally, C-reactive protein (CRP) correlated positively to the levels of intermediate monocytes and negatively to the recovery of DC subsets. By exploring the myeloid compartments, we show here that alterations in the immune landscape remain more than 6 months after severe COVID-19, which could be indicative of ongoing healing and/or persistence of viral antigens.

Aberrant Dendritic Cell Subsets in Patients with Myasthenia Gravis and Related Clinical Features

Introduction: Dendritic cells (DCs) play critical roles in the pathogenesis of myasthenia gravis (MG), and a series of DC-based experimental strategies for MG have recently been developed. However, the definite roles of different DC subsets in the mechanism of MG have scarcely been covered by previous studies. The present study aimed to investigate the levels of three main DC subsets, plasmacytoid DCs (pDCs) (CD303 positive) and two distinct subsets of conventional DCs (cDCs), namely CD1c⁺ cDCs and CD141⁺ cDCs, in MG patients and analyze related clinical features. Methods: From January 2016 to December 2020, 160 newly diagnosed MG patients and matched healthy controls (n = 160) were included in the study, and their clinical data were collected. The blood samples from MG patients before treatment and controls were collected for flow cytometry analysis. A total of 14 MG thymoma, 24 control thymoma, and 3 thymic cysts were used to immunostain the DC subsets. Results: The flow cytometry analysis showed a significantly higher frequency of circulating pDCs, CD1c⁺ cDCs, and CD141⁺ cDCs in MG patients than in healthy controls (p < 0.001 for all). Patients with early-onset MG (<50 years old) had a lower frequency of circulating pDCs but a higher frequency of circulating CD1c⁺ cDCs than those with late-onset MG (≥50 years old) (p = 0.014 and p = 0.025, respectively). The frequency of circulating pDCs was positively associated with the clinical severity of late-onset MG patients (r = 0.613, p < 0.001). 64.3% (9/14) of MG thymoma is of type B2 under the World Health Organization classification, which is higher than that in control thymoma (33.3%, 8/24) (p = 0.019). For type B2 thymoma, there were significantly more pDCs but fewer CD1c⁺ cDCs in MG thymoma than in the controls. Conclusion: The distribution of aberrant pDCs, CD1c⁺ cDCs, and CD141⁺ cDCs in MG patients displayed age- and thymoma-related differences, which may contribute to the impaired immune tolerance and lead to the onset of MG.

Study and isolation of human intestinal dendritic cell and macrophage subsets.

Dendritic cells and macrophages are the main antigen-presenting cells (APC). In the gut, they control the mechanisms of tolerance toward commensals and nutrients, at the time that they maintain their capacity to trigger immune responses against invading pathogens. Nevertheless, this balance is not perfect as it can get disrupted like in inflammatory bowel disease (where they drive an abnormal immune response against the microbiota) or in coeliac disease (where they trigger an immune response against dietary gluten). Therefore, the study of human intestinal APC subsets is crucial not just to get a deeper insight in the mechanisms of human intestinal homeostasis, but also to understand the pathogenesis of inflammatory bowel disease and coeliac disease. Nevertheless, their study is quite complicated as despite their relevance, their numbers are scare in the intestinal mucosa. Therefore, we hereby describe different approaches to study human intestinal dendritic cell and macrophage subsets in the human intestinal mucosa.

Human Dendritic Cell Subset Isolation by Magnetic Bead Sorting: A Protocol to Efficiently Obtain Pure Populations.

Dendritic cells have been investigated for cell-based immunotherapy for various applications. The low abundance of dendritic cells in blood hampers their clinical application, resulting in the use of monocyte-derived dendritic cells as an alternative cell type. Limited knowledge is available regarding blood-circulating human dendritic cells, which can be divided into three subsets: type 2 conventional dendritic cells, type 1 conventional dendritic cells, and plasmacytoid dendritic cells. These subsets exhibit unique and desirable features for dendritic cell-based therapies. To enable efficient and reliable human research on dendritic cell subsets, we developed an efficient isolation protocol for the three human dendritic cell subsets, resulting in pure populations. The sequential steps include peripheral blood mononuclear cell isolation, magnetic-microbead lineage depletion (CD14, CD56, CD3, and CD19), and individual magnetic-microbead isolation of the three human dendritic cell subsets.

Use of CRISPR/CAS9 Technologies to Study the Role of TLR in Dendritic Cell Subsets.

Dendritic cells (DCs) have a significant role in coordinating both innate and adaptive immunity by serving as sentinels that detect invaders and initiate immune responses to eliminate them, as well as presenting antigens to activate adaptive immune responses that are specific to the antigen and the context in which it was detected. The regulation of DC functions is complex and involves intracellular drivers such as transcription factors and signaling pathways, as well as intercellular interactions with adhesion molecules, chemokines, and their receptors in the microenvironment. Toll-like receptors (TLRs) are crucial for DCs to detect pathogen-associated molecular patterns (PAMPs) and initiate downstream signaling pathways that lead to DC maturation and education in bridging with adaptive immunity, including the upregulation of MHC class II expression, induction of CD80, CD86, and CD40, and production of innate cytokines. Understanding the TLR pathways that DCs use to respond to innate immune stimuli and convert them into adaptive responses is important for new therapeutic targets identification.We present a novel platform that offers a fast and affordable CRISPR-Cas9 screening of genes that are involved in dendritic cells' TLR-dependent activation. Using CRISPR/Cas9 screening to target individual TLR genes in different dendritic cell subsets allows the identification of TLR-dependent pathways that regulate dendritic cell activation and cytokine production. This approach offers the efficient targeting of TLR driver genes to modulate the immune response and identify novel immune response regulators, establishing a causal link between these regulators and functional phenotypes based on genotypes.

The intestinal microenvironment shapes macrophage and dendritic cell identity and function

The gut comprises the largest body interface with the environment and is continuously exposed to nutrients, food antigens, and commensal microbes, as well as to harmful pathogens. Subsets of both macrophages and dendritic cells (DCs) are present throughout the intestinal tract, where they primarily inhabit the gut-associate lymphoid tissue (GALT), such as Peyer's patches and isolated lymphoid follicles. In addition to their role in taking up and presenting antigens, macrophages and DCs possess extensive functional plasticity and these cells play complementary roles in maintaining immune homeostasis in the gut by preventing aberrant immune responses to harmless antigens and microbes and by promoting host defense against pathogens. The ability of macrophages and DCs to induce either inflammation or tolerance is partially lineage imprinted, but can also be dictated by their activation state, which in turn is determined by their specific microenvironment. These cells express several surface and intracellular receptors that detect danger signals, nutrients, and hormones, which can affect their activation state. DCs and macrophages play a fundamental role in regulating T cells and their effector functions. Thus, modulation of intestinal mucosa immunity by targeting antigen presenting cells can provide a promising approach for controlling pathological inflammation. In this review, we provide an overview on the characteristics, functions, and origins of intestinal macrophages and DCs, highlighting the intestinal microenvironmental factors that influence their functions during homeostasis. Unraveling the mechanisms by which macrophages and DCs regulate intestinal immunity will deepen our understanding on how the immune system integrates endogenous and exogenous signals in order to maintain the host's homeostasis.

Enrichment of Large Numbers of Splenic Mouse Dendritic Cells After Injection of Flt3L-Producing Tumor Cells.

Dendritic cells (DCs) are antigen-presenting cells (APCs) that shape innate and adaptive immunity. There are multiple subsets of DCs distinguished according to their phenotype and functional specialization. DCs are present in lymphoid organs and across multiple tissues. However, their frequency and numbers at these sites are very low making their functional study difficult. Multiple protocols have been developed to generate DCs in vitro from bone marrow progenitors, but they do not fully recapitulate DC complexity found in vivo. Therefore, directly amplifying endogenous DCs in vivo appears as an option to overcome this specific caveat. In this chapter, we describe a protocol to amplify murine DCs in vivo by the injection of a B16 melanoma cell line expressing the trophic factor FMS-like tyrosine kinase 3 ligand (Flt3L). We have also compared two methods of magnetic sorting of amplified DCs, both giving high yields of total murine DCs, but different representation of the main DC subsets found in vivo.

Origin, Phenotype, and Function of Mouse Dendritic Cell Subsets.

Dendritic cells are cells of hematopoietic origin that are specialized in antigen presentation and instruction of innate and adaptive immune responses. They are a heterogenous group of cells populating lymphoid organs and most tissues. Dendritic cells are commonly separated in three main subsets that differ in their developmental paths, phenotype, and functions. Most studies on dendritic cells were done primarily in mice; therefore, in this chapter, we propose to summarize the current knowledge and recent progress on mouse dendritic cell subsets' development, phenotype, and functions.