Spatiotemporal Adaptations of Macrophage and Dendritic Cell Development and Function

NUSAP1 Promotes Immunity and Apoptosis by the SHCBP1/JAK2/STAT3 Phosphorylation Pathway to Induce Dendritic Cell Generation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common type of liver cancer and is associated with high morbidity and mortality rates. The aims of this study were to investigate the immune-promoting action of nucleolar and spindle-associated protein 1 (NUSAP1) and identify an immunotherapy target for HCC. The Cancer Genome Atlas (TCGA) was used to analyze interaction molecules and immune correlation. The interaction between NUSAP1 and SHC binding and spindle associated 1 (SHCBP1) was examined. The role of the SHCBP1/Janus kinase 2/signal transducer and activator of transcription 3 (SHCBP1/JAK2/STAT3) pathway in this process was explored. After co-culture with HCC cell lines, the differentiation of peripheral blood mononuclear cells (PBMCs) into dendritic cells (DC) was evaluated by measuring the expression of surface factors CD1a and CD86. Pathological tissues from 50 patients with HCC were collected to validate the results of cell experiments. The expression levels of CD1a and CD86 in tissues were also determined. The results show that NUSAP1 interacted with SHCBP1 and was positively correlated with DC. In HCC cell lines, an interaction was observed between NUSAP1 and SHCBP1. It was verified that NUSAP1 inhibited the JAK2/STAT3 phosphorylation pathway by blocking SHCBP1. After co-culture, the levels of CD1a and CD86 in PBMC were elevated. In the clinical specimens, CD1a and CD86 expression levels were significantly higher in the high-NUSAP1 group versus the low-NUSAP1 group. In Summary, NUSAP1 enhanced immunity by inhibiting the SHCBP1/JAK2/STAT3 phosphorylation pathway and promoted DC generation and HCC apoptosis. NUSAP1 may be a target of immunotherapy for HCC.

Roles and therapeutic targeting of dendritic cells in liver fibrosis

Liver fibrosis is a common pathological condition marked by excessive accumulation of extracellular matrix proteins, resulting in irreversible cirrhosis and cancer. Dendritic cells (DCs) act as the crucial component of hepatic immunity and are believed to affect fibrosis by regulating the proliferation and differentiation of hepatic stellate cells (HSCs), a key mediator of fibrogenesis, and by interplaying with immune cells in the liver. This review concisely describes the process of fibrogenesis, and the phenotypic and functional characteristics of DCs in the liver. Besides, it focuses on the interaction between DCs and HSCs, T cells, and natural killer (NK) cells, as well as the dual roles of DCs in liver fibrosis, for the sake of exploring the potential of targeting DCs as a therapeutic strategy for the disease.

Macrophages in tissue repair and regeneration: insights from zebrafish

Macrophages play crucial and versatile roles in regulating tissue repair and regeneration upon injury. However, due to their complex compositional heterogeneity and functional plasticity, deciphering the nature of different macrophage subpopulations and unraveling their dynamics and precise roles during the repair process have been challenging. With its distinct advantages, zebrafish (Danio rerio) has emerged as an invaluable model for studying macrophage development and functions, especially in tissue repair and regeneration, providing valuable insights into our understanding of macrophage biology in health and diseases. In this review, we present the current knowledge and challenges associated with the role of macrophages in tissue repair and regeneration, highlighting the significant contributions made by zebrafish studies. We discuss the unique advantages of the zebrafish model, including its genetic tools, imaging techniques, and regenerative capacities, which have greatly facilitated the investigation of macrophages in these processes. Additionally, we outline the potential of zebrafish research in addressing the remaining challenges and advancing our understanding of the intricate interplay between macrophages and tissue repair and regeneration.

Deciphering the performance of macrophages in tumour microenvironment: a call for precision immunotherapy

Macrophages infiltrating tumour tissues or residing in the microenvironment of solid tumours are known as tumour-associated macrophages (TAMs). These specialized immune cells play crucial roles in tumour growth, angiogenesis, immune regulation, metastasis, and chemoresistance. TAMs encompass various subpopulations, primarily classified into M1 and M2 subtypes based on their differentiation and activities. M1 macrophages, characterized by a pro-inflammatory phenotype, exert anti-tumoural effects, while M2 macrophages, with an anti-inflammatory phenotype, function as protumoural regulators. These highly versatile cells respond to stimuli from tumour cells and other constituents within the tumour microenvironment (TME), such as growth factors, cytokines, chemokines, and enzymes. These stimuli induce their polarization towards one phenotype or another, leading to complex interactions with TME components and influencing both pro-tumour and anti-tumour processes.This review comprehensively and deeply covers the literature on macrophages, their origin and function as well as the intricate interplay between macrophages and the TME, influencing the dual nature of TAMs in promoting both pro- and anti-tumour processes. Moreover, the review delves into the primary pathways implicated in macrophage polarization, examining the diverse stimuli that regulate this process. These stimuli play a crucial role in shaping the phenotype and functions of macrophages. In addition, the advantages and limitations of current macrophage based clinical interventions are reviewed, including enhancing TAM phagocytosis, inducing TAM exhaustion, inhibiting TAM recruitment, and polarizing TAMs towards an M1-like phenotype. In conclusion, while the treatment strategies targeting macrophages in precision medicine show promise, overcoming several obstacles is still necessary to achieve an accessible and efficient immunotherapy.

Sepsis-trained macrophages promote antitumoral tissue-resident T cells

Sepsis induces immune alterations, which last for months after the resolution of illness. The effect of this immunological reprogramming on the risk of developing cancer is unclear. Here we use a national claims database to show that sepsis survivors had a lower cumulative incidence of cancers than matched nonsevere infection survivors. We identify a chemokine network released from sepsis-trained resident macrophages that triggers tissue residency of T cells via CCR2 and CXCR6 stimulations as the immune mechanism responsible for this decreased risk of de novo tumor development after sepsis cure. While nonseptic inflammation does not provoke this network, laminarin injection could therapeutically reproduce the protective sepsis effect. This chemokine network and CXCR6 tissue-resident T cell accumulation were detected in humans with sepsis and were associated with prolonged survival in humans with cancer. These findings identify a therapeutically relevant antitumor consequence of sepsis-induced trained immunity.

TGF-β1 induces PD-1 expression in macrophages through SMAD3/STAT3 cooperative signaling in chronic inflammation

Programmed cell death protein 1 (PD-1), a coinhibitory T cell checkpoint, is also expressed on macrophages in pathogen- or tumor-driven chronic inflammation. Increasing evidence underscores the importance of PD-1 on macrophages for dampening immune responses. However, the mechanism governing PD-1 expression in macrophages in chronic inflammation remains largely unknown. TGF-β1 is abundant within chronic inflammatory microenvironments. Here, based on public databases, significantly positive correlations between PDCD1 and TGFB1 gene expression were observed in most human tumors. Of note, among immune infiltrates, macrophages as the predominant infiltrate expressed higher PDCD1 and TGFBR1/TGFBR2 genes. MC38 colon cancer and Schistosoma japonicum infection were used as experimental models for chronic inflammation. PD-1hi macrophages from chronic inflammatory tissues displayed an immunoregulatory pattern and expressed a higher level of TGF-β receptors. Either TGF-β1-neutralizing antibody administration or macrophage-specific Tgfbr1 knockdown largely reduced PD-1 expression on macrophages in animal models. We further demonstrated that TGF-β1 directly induced PD-1 expression on macrophages. Mechanistically, TGF-β1-induced PD-1 expression on macrophages was dependent on SMAD3 and STAT3, which formed a complex at the Pdcd1 promoter. Collectively, our study shows that macrophages adapt to chronic inflammation through TGF-β1-triggered cooperative SMAD3/STAT3 signaling that induces PD-1 expression and modulates macrophage function.

Systemic inflammatory response syndrome triggered by blood-borne pathogens induces prolonged dendritic cell paralysis and immunosuppression

Blood-borne pathogens can cause systemic inflammatory response syndrome (SIRS) followed by protracted, potentially lethal immunosuppression. The mechanisms responsible for impaired immunity post-SIRS remain unclear. We show that SIRS triggered by pathogen mimics or malaria infection leads to functional paralysis of conventional dendritic cells (cDCs). Paralysis affects several generations of cDCs and impairs immunity for 3-4 weeks. Paralyzed cDCs display distinct transcriptomic and phenotypic signatures and show impaired capacity to capture and present antigens in vivo. They also display altered cytokine production patterns upon stimulation. The paralysis program is not initiated in the bone marrow but during final cDC differentiation in peripheral tissues under the influence of local secondary signals that persist after resolution of SIRS. Vaccination with monoclonal antibodies that target cDC receptors or blockade of transforming growth factor β partially overcomes paralysis and immunosuppression. This work provides insights into the mechanisms of paralysis and describes strategies to restore immunocompetence post-SIRS.

Multi-omics studies in interpreting the evolving standard model for immune functions

A standard model that is able to generalize data on myriad involvement of the immune system in organismal physio-pathology and to provide a unified evolutionary teleology for immune functions in multicellular organisms remains elusive. A number of such 'general theories of immunity' have been proposed based on contemporaneously available data, starting with the usual description of self-nonself discrimination, followed by the 'danger model' and the more recent 'discontinuity theory.' More recent data deluge on involvement of immune mechanisms in a wide variety of clinical contexts, a number of which fail to get readily accommodated into the available teleologic standard models, makes deriving a standard model of immunity more challenging. But technological advances enabling multi-omics investigations into an ongoing immune response, covering genome, epigenome, coding and regulatory transcriptome, proteome, metabolome and tissue-resident microbiome, bring newer opportunities for developing a more integrative insight into immunocellular mechanisms within different clinical contexts. The new ability to map the heterogeneity of composition, trajectory and endpoints of immune responses, in both health and disease, also necessitates incorporation into the potential standard model of immune functions, which again can only be achieved through multi-omics probing of immune responses and integrated analyses of the multi-dimensional data.

Retinoic acid drives intestine-specific adaptation of effector ILC2s originating from distant sites

Adaptation of immune cells to tissue-specific microenvironments is a crucial process in homeostasis and inflammation. Here, we show that murine effector type 2 innate lymphoid cells (ILC2s) from various organs are equally effective in repopulating ILC2 niches in other anatomical locations where they adapt tissue-specific phenotypes of target organs. Single-cell transcriptomics of ILC2 populations revealed upregulation of retinoic acid (RA) signaling in ILC2s during adaptation to the small intestinal microenvironment, and RA signaling mediated reprogramming of kidney effector ILC2s toward the small intestinal phenotype in vitro and in vivo. Inhibition of intestinal ILC2 adaptation by blocking RA signaling impaired worm expulsion during Strongyloides ratti infection, indicating functional importance of ILC2 tissue imprinting. In conclusion, this study highlights that effector ILC2s retain the ability to adapt to changing tissue-specific microenvironments, enabling them to exert tissue-specific functions, such as promoting control of intestinal helminth infections.

Preparation, identification, and application of PEG/ZIF-8@ Dendrobium huoshanense polysaccharide as an adjuvant to enhance immune responses

Zeolitic imidazolate framework-8 (ZIF-8) nanoparticles loaded with polysaccharides are excellent drug-delivery carriers with high loading capacity and pH sensitivity. This study describes the one-step encapsulation of Dendrobium huoshanense polysaccharides (DHP) in ZIF-8. The resultant PEG6000/ZIF-8@DHP complex exhibited drug release properties in acidic microenvironments, possessed water solubility, demonstrated high drug loading capacity, and displayed effective encapsulation. The effects of PEG6000/ZIF-8@ DHP administration on immunoregulation, antioxidant activities, and resistance against Aeromonas veronii in channel catfish were assessed. The study revealed that the PEG6000/ZIF-8@DHP complex stimulated cellular proliferation and phagocytosis, while also inducing the production of cytokines and nitric oxide. Additionally, the complex exhibited improved antioxidant properties and increased serum lysozyme and alkaline phosphatase activities. PEG6000/ZIF-8@DHP exhibited efficacy in vivo against Aeromonas veronii infection. These results indicate that PEG6000/ZIF-8@DHP is an efficient immunostimulant and vaccine adjuvant for enhancing immunity in channel catfish.

Development and function of chicken XCR1+ conventional dendritic cells

Conventional dendritic cells (cDCs) are antigen-presenting cells (APCs) that play a central role in linking innate and adaptive immunity. cDCs have been well described in a number of different mammalian species, but remain poorly characterised in the chicken. In this study, we use previously described chicken cDC specific reagents, a novel gene-edited chicken line and single-cell RNA sequencing (scRNAseq) to characterise chicken splenic cDCs. In contrast to mammals, scRNAseq analysis indicates that the chicken spleen contains a single, chemokine receptor XCR1 expressing, cDC subset. By sexual maturity the XCR1+ cDC population is the most abundant mononuclear phagocyte cell subset in the chicken spleen. scRNAseq analysis revealed substantial heterogeneity within the chicken splenic XCR1+ cDC population. Immature MHC class II (MHCII)LOW XCR1+ cDCs expressed a range of viral resistance genes. Maturation to MHCIIHIGH XCR1+ cDCs was associated with reduced expression of anti-viral gene expression and increased expression of genes related to antigen presentation via the MHCII and cross-presentation pathways. To visualise and transiently ablate chicken XCR1+ cDCs in situ, we generated XCR1-iCaspase9-RFP chickens using a CRISPR-Cas9 knockin transgenesis approach to precisely edit the XCR1 locus, replacing the XCR1 coding region with genes for a fluorescent protein (TagRFP), and inducible Caspase 9. After inducible ablation, the chicken spleen is initially repopulated by immature CD1.1+ XCR1+ cDCs. XCR1+ cDCs are abundant in the splenic red pulp, in close association with CD8+ T-cells. Knockout of XCR1 prevented this clustering of cDCs with CD8+ T-cells. Taken together these data indicate a conserved role for chicken and mammalian XCR1+ cDCs in driving CD8+ T-cells responses.

Factors impacting the benefits and pathogenicity of Th17 cells in the tumor microenvironment

Tumor development is closely associated with a complex tumor microenvironment, which is composed of tumor cells, blood vessels, tumor stromal cells, infiltrating immune cells, and associated effector molecules. T helper type 17 (Th17) cells, which are a subset of CD4+ T cells and are renowned for their ability to combat bacterial and fungal infections and mediate inflammatory responses, exhibit context-dependent effector functions. Within the tumor microenvironment, different molecular signals regulate the proliferation, differentiation, metabolic reprogramming, and phenotypic conversion of Th17 cells. Consequently, Th17 cells exert dual effects on tumor progression and can promote or inhibit tumor growth. This review aimed to investigate the impact of various alterations in the tumor microenvironment on the antitumor and protumor effects of Th17 cells to provide valuable clues for the exploration of additional tumor immunotherapy strategies.

RUFY3 regulates endolysosomes perinuclear positioning, antigen presentation and migration in activated phagocytes

Endo-lysosomes transport along microtubules and clustering in the perinuclear area are two necessary steps for microbes to activate specialized phagocyte functions. We report that RUN and FYVE domain-containing protein 3 (RUFY3) exists as two alternative isoforms distinguishable by the presence of a C-terminal FYVE domain and by their affinity for phosphatidylinositol 3-phosphate on endosomal membranes. The FYVE domain-bearing isoform (iRUFY3) is preferentially expressed in primary immune cells and up-regulated upon activation by microbes and Interferons. iRUFY3 is necessary for ARL8b + /LAMP1+ endo-lysosomes positioning in the pericentriolar organelles cloud of LPS-activated macrophages. We show that iRUFY3 controls macrophages migration, MHC II presentation and responses to Interferon-γ, while being important for intracellular Salmonella replication. Specific inactivation of rufy3 in phagocytes leads to aggravated pathologies in mouse upon LPS injection or bacterial pneumonia. This study highlights the role of iRUFY3 in controlling endo-lysosomal dynamics, which contributes to phagocyte activation and immune response regulation.

Transcriptional regulation of dendritic cell development and function

Dendritic cells (DCs) are sentinel immune cells that form a critical bridge linking the innate and adaptive immune systems. Extensive research addressing the cellular origin and heterogeneity of the DC network has revealed the essential role played by the spatiotemporal activity of key transcription factors. In response to environmental signals DC mature but it is only following the sensing of environmental signals that DC can induce an antigen specific T cell response. Thus, whilst the coordinate action of transcription factors governs DC differentiation, sensing of environmental signals by DC is instrumental in shaping their functional properties. In this review, we provide an overview that focuses on recent advances in understanding the transcriptional networks that regulate the development of the reported DC subsets, shedding light on the function of different DC subsets. Specifically, we discuss the emerging knowledge on the heterogeneity of cDC2s, the ontogeny of pDCs, and the newly described DC subset, DC3. Additionally, we examine critical transcription factors such as IRF8, PU.1, and E2-2 and their regulatory mechanisms and downstream targets. We highlight the complex interplay between these transcription factors, which shape the DC transcriptome and influence their function in response to environmental stimuli. The information presented in this review provides essential insights into the regulation of DC development and function, which might have implications for developing novel therapeutic strategies for immune-related diseases.

CCL5-producing migratory dendritic cells guide CCR5+ monocytes into the draining lymph nodes

Dendritic cells (DCs) and monocytes capture, transport, and present antigen to cognate T cells in the draining lymph nodes (LNs) in a CCR7-dependent manner. Since only migratory DCs express this chemokine receptor, it is unclear how monocytes reach the LN. In steady-state and following inhalation of several PAMPs, scRNA-seq identified LN mononuclear phagocytes as monocytes, resident, or migratory type 1 and type 2 conventional (c)DCs, despite the downregulation of Xcr1, Clec9a, H2-Ab1, Sirpa, and Clec10a transcripts on migratory cDCs. Migratory cDCs, however, upregulated Ccr7, Ccl17, Ccl22, and Ccl5. Migratory monocytes expressed Ccr5, a high-affinity receptor for Ccl5. Using two tracking methods, we observed that both CD88hiCD26lomonocytes and CD88-CD26hi cDCs captured inhaled antigens in the lung and migrated to LNs. Antigen exposure in mixed-chimeric Ccl5-, Ccr2-, Ccr5-, Ccr7-, and Batf3-deficient mice demonstrated that while antigen-bearing DCs use CCR7 to reach the LN, monocytes use CCR5 to follow CCL5-secreting migratory cDCs into the LN, where they regulate DC-mediated immunity.

Armored modified vaccinia Ankara in cancer immunotherapy

Cancer immunotherapy relies on unleashing the patient´s immune system against tumor cells. Cancer vaccines aim to stimulate both the innate and adaptive arms of immunity to achieve durable clinical responses. Some roadblocks for a successful cancer vaccine in the clinic include the tumor antigen of choice, the adjuvants employed to strengthen antitumor-specific immune responses, and the risks associated with enhancing immune-related adverse effects in patients. Modified vaccinia Ankara (MVA) belongs to the family of poxviruses and is a versatile vaccine platform that combines several attributes crucial for cancer therapy. First, MVA is an excellent inducer of innate immune responses leading to type I interferon secretion and induction of T helper cell type 1 (Th1) immune responses. Second, it elicits robust and durable humoral and cellular immunity against vector-encoded heterologous antigens. Third, MVA has enormous genomic flexibility, which allows for the expression of multiple antigenic and costimulatory entities. And fourth, its replication deficit in human cells ensures a excellent safety profile. In this review, we summarize the current understanding of how MVA induces innate and adaptive immune responses. Furthermore, we will give an overview of the tumor-associated antigens and immunomodulatory molecules that have been used to armor MVA and describe their clinical use. Finally, the route of MVA immunization and its impact on therapeutic efficacy depending on the immunomodulatory molecules expressed will be discussed.

Metaphocytes are IL-22BP-producing cells regulated by ETS transcription factor Spic and essential for zebrafish barrier immunity

Metaphocytes are tissue-resident macrophage (TRM)/dendritic cell (DC)-like cells of non-hematopoietic origin in zebrafish barrier tissues. One remarkable property of metaphocytes is their ability to capture soluble antigens from the external environment via transepithelial protrusions, a unique function manifested by specialized subpopulations of the TRMs/DCs in mammal barrier tissues. Yet, how metaphocytes acquire myeloid-like cell properties from non-hematopoietic precursors and how they regulate barrier immunity remains unknown. Here, we show that metaphocytes are in situ generated from local progenitors guided by the ETS transcription factor Spic, the deficiency of which results in the absence of metaphocytes. We further document that metaphocytes are the major IL-22BP-producing cells, and the depletion of metaphocytes causes dysregulated barrier immunity that resembles the phenotype of IL-22BP-deficient mice. These findings reveal the ontogeny, development, and function of metaphocytes in zebrafish, which facilitates our understanding of the nature and function of the mammalian TRM/DC counterparts.

Macrophages CD163+ and Factor XIIIa+ Provide a First-Line Defence against Proliferative Verrucous Leukoplakia Antigens

This study aimed to evaluate the density of the dendritic cells (DCs) and macrophages in oral leukoplakia (OL) and proliferative verrucous leukoplakia (PVL) by immunohistochemical analysis. We analysed paraffined tissue samples of PVL (n = 27), OL (n = 20), and inflammatory fibrous hyperplasia (n = 20) as the control group using the immunomarkers for DCs (CD1a, CD207, CD83, CD208 and CD123) and macrophages (CD68, CD163, FXIIIa and CD209). A quantitative analysis of positive cells in the epithelial and subepithelial areas was determined. Our results showed a reduction in CD208+ cells in the subepithelial area of the OL and PVL compared to the control. Additionally, we found a higher density of FXIIIa+ and CD163+ cells in the subepithelial area in PVL compared to the OL and control. Four-way MANOVA revealed a relationship between increased CD123+ cell density in the subepithelial area of “high-risk” samples regardless of disease. Macrophages provide the first line of defence against PVL antigens, suggesting a distinct pattern of innate immune system activation in PVL compared to OL, which may contribute to the complexity and the high rate of malignant transformation in the PVL.

Exosomal miRNAs-mediated macrophage polarization and its potential clinical application

Macrophages are highly heterogeneous and plastic immune cells that play an important role in the fight against pathogenic microorganisms and tumor cells. After different stimuli, macrophages can polarize to the M1 phenotype to show a pro-inflammatory effect and the M2 phenotype to show an anti-inflammatory effect. The balance of macrophage polarization is highly correlated with disease progression, and therapeutic approaches to reprogram macrophages by targeting macrophage polarization are feasible. There are a large number of exosomes in tissue cells, which can transmit information between cells. In particular, microRNAs (miRNAs) in the exosomes can regulate the polarization of macrophages and further affect the progression of various diseases. At the same time, exosomes are also effective "drug" carriers, laying the foundation for the clinical application of exosomes. This review describes some pathways involved in M1/M2 macrophage polarization and the effects of miRNA carried by exosomes from different sources on the polarization of macrophages. Finally, the application prospects and challenges of exosomes/exosomal miRNAs in clinical treatment are also discussed.

pDC-like cells are pre-DC2 and require KLF4 to control homeostatic CD4 T cells

Plasmacytoid dendritic cells (pDCs) have been shown to play an important role during immune responses, ranging from initial viral control through the production of type I interferons to antigen presentation. However, recent studies uncovered unexpected heterogeneity among pDCs. We identified a previously uncharacterized immune subset, referred to as pDC-like cells, that not only resembles pDCs but also shares conventional DC (cDC) features. We show that this subset is a circulating precursor distinct from common DC progenitors, with prominent cDC2 potential. Our findings from human CD2-iCre and CD300c-iCre lineage tracing mouse models suggest that a substantial fraction of cDC2s originates from pDC-like cells, which can therefore be referred to as pre-DC2. This precursor subset responds to homeostatic cytokines, such as macrophage colony stimulating factor, by expanding and differentiating into cDC2 that efficiently prime T helper 17 (TH17) cells. Development of pre-DC2 into CX3CR1+ ESAM- cDC2b but not CX3CR1- ESAM+ cDC2a requires the transcription factor KLF4. Last, we show that, under homeostatic conditions, this developmental pathway regulates the immune threshold at barrier sites by controlling the pool of TH17 cells within skin-draining lymph nodes.

The Human Dendritic Cell Atlas: An Integrated Transcriptional Tool to Study Human Dendritic Cell Biology

Dendritic cells (DCs) are functionally diverse and are present in most adult tissues, but deep understanding of human DC biology is hampered by relatively small numbers of these in circulation and their short lifespan in human tissues. We built a transcriptional atlas of human DCs by combining samples from 14 expression profiling studies derived from 10 laboratories. We identified significant gene expression variation of DC subset-defining markers across tissue type and upon viral or bacterial stimulation. We further highlight critical gaps between in vitro-derived DC subsets and their in vivo counterparts and provide evidence that monocytes or cord blood progenitor in vitro-differentiated DCs fail to capture the repertoire of primary DC subsets or behaviors. In constructing a reference DC atlas, we provide an important resource for the community wishing to identify and annotate tissue-specific DC subsets from single-cell datasets, or benchmark new in vitro models of DC biology.

Immune modulation after traumatic brain injury

Traumatic brain injury (TBI) induces instant activation of innate immunity in brain tissue, followed by a systematization of the inflammatory response. The subsequent response, evolved to limit an overwhelming systemic inflammatory response and to induce healing, involves the autonomic nervous system, hormonal systems, and the regulation of immune cells. This physiological response induces an immunosuppression and tolerance state that promotes to the occurrence of secondary infections. This review describes the immunological consequences of TBI and highlights potential novel therapeutic approaches using immune modulation to restore homeostasis between the nervous system and innate immunity.