HIV-1-Specific CD11c+ CD8+ T Cells Display Low PD-1 Expression and Strong Anti-HIV-1 Activity.

Exhaustion of HIV-1-specific CD8+ T cells prevents optimal control of HIV-1 infection. Identifying unconventional CD8+ T cell subsets to effectively control HIV-1 replication is vital. In this study, the role of CD11c+ CD8+ T cells during HIV-1 infection was evaluated. The frequencies of CD11c+ CD8+ T cells significantly increased and were negatively correlated with viral load in HIV-1-infected treatment-naïve patients. HIV-1-specific cells were enriched more in CD11c+ CD8+ T cells than in CD11c- CD8+ T cells, which could be induced by HIV-1-derived overlapping peptides, marking an HIV-1-specific CD8+ T cell population. This subset expressed higher levels of activating markers (CD38 and HLA-DR), cytotoxic markers (granzyme B, perforin, and CD107a), and cytokines (IL-2 and TNF-α), with lower levels of PD-1 compared to the CD11c- CD8+ T cell subset. In vitro analysis verified that CD11c+ CD8+ T cells displayed a stronger HIV-1-specific killing capacity than the CD11c- counterparts. These findings indicate that CD11c+ CD8+ T cells have potent immunotherapeutic efficacy in controlling HIV-1 infection.

CD11c+CD163+ Cells and Signal Transducer and Activator of Transcription 3 (STAT3) Expression Are Common in Melanoma Leptomeningeal Disease.

Leptomeningeal disease (LMD) in melanoma patients is associated with significant neurological sequela and has a dismal outcome, with survival measured typically in weeks. Despite the therapeutic benefit of targeted therapies and immunotherapies for Stage IV melanoma, patients with LMD do not typically benefit. A deeper understanding of the tumor microenvironment (TME) of LMD may provide more appropriate therapeutic selection. A retrospective analysis of subjects who underwent surgical resection with LMD (n=8) were profiled with seven color multiplex staining to evaluate the expression of the global immune suppressive hub - the signal transducer and activator of transcription 3 (STAT3) and for the presence of CD3+ T cells, CD68+ monocyte-derived cells, CD163+ immune suppressive macrophages, and CD11c+ cells [potential dendritic cells (DCs)] in association with the melanoma tumor marker S100B and DAPI for cellular nuclear identification. High-resolution cellular imaging and quantification was conducted using the Akoya Vectra Polaris. CD11c+ cells predominate in the TME (10% of total cells), along with immunosuppressive macrophages (2%). Another potential subset of DCs co-expressing CD11c+ and the CD163+ immunosuppressive marker is frequently present (8/8 of specimens, 8%). Occasional CD3+ T cells are identified, especially in the stroma of the tumor (p=0.039). pSTAT3 nuclear expression is heterogeneous in the various immune cell populations. Occasional immune cluster interactions can be seen in the stroma and on the edge. In conclusion, the TME of LMD is largely devoid of CD3+ T cells but is enriched in immune suppression and innate immunity.

Serum amyloid A delivers retinol to intestinal myeloid cells to promote adaptive immunity.

Vitamin A and its derivative retinol are essential for the development of intestinal adaptive immunity. Retinoic acid (RA)­producing myeloid cells are central to this process, but how myeloid cells acquire retinol for conversion to RA is unknown. Here, we show that serum amyloid A (SAA) proteins­retinol-binding proteins induced in intestinal epithelial cells by the microbiota­deliver retinol to myeloid cells. We identify low-density lipoprotein (LDL) receptor­related protein 1 (LRP1) as an SAA receptor that endocytoses SAA-retinol complexes and promotes retinol acquisition by RA-producing intestinal myeloid cells. Consequently, SAA and LRP1 are essential for vitamin A­dependent immunity, including B and T cell homing to the intestine and immunoglobulin A production. Our findings identify a key mechanism by which vitamin A promotes intestinal immunity.

The number and phenotype of myocardial and adipose tissue CD68+ cells is associated with cardiovascular and metabolic disease in heart surgery patients.

BACKGROUND AND AIMS: CD68+ cells are a potent source of inflammatory cytokines in adipose tissue and myocardium. The development of low-grade inflammation in adipose tissue is implicated in the pathogenesis of obesity-associated disorders including type 2 diabetes mellitus (T2DM) and cardiovascular disease. The main aim of the study was to characterize and quantify myocardial and adipose tissue CD68+ cells and adipose tissue crown-like structures (CLS) in patients with obesity, coronary artery disease (CAD) and T2DM. METHODS AND RESULTS: Samples were obtained from the right atrium, epicardial (EAT) and subcutaneous adipose tissue (SAT) during elective heart surgery (non-obese, n = 34 patients; obese, n = 24 patients). Immunohistochemistry was used to visualize CD68+ cells. M1-polarized macrophages were visualized by immunohistochemical detection of CD11c. The proportion of CD68+ cells was higher in EAT than in SAT (43.4 ± 25.0 versus 32.5 ± 23.1 cells per 1 mm2; p = 0.015). Myocardial CD68+ cells were more abundant in obese patients (45.6 ± 24.5 versus 27.7 ± 14.8 cells per 1 mm2; p = 0.045). In SAT, CD68+ cells were more frequent in CAD patients (37.3 ± 23.0 versus 23.1 ± 20.9 cells per 1 mm2; p = 0.012). Patients having CLS in their SAT had higher average BMI (34.1 ± 6.4 versus 29.0 ± 4.5; p = 0.024). CONCLUSIONS: Regional-based increases in the frequency of CD68+ cells and changes of their phenotype in CLS were detected in obese patients and CAD patients. Therapeutic modulation of adipose tissue inflammation may represent a target for treatment of obesity.

Monocyte-Derived CD11c+ Cells Acquire Plasmodium from Hepatocytes to Prime CD8 T Cell Immunity to Liver-Stage Malaria.

Plasmodium sporozoites inoculated by mosquitoes migrate to the liver and infect hepatocytes prior to release of merozoites that initiate symptomatic blood-stage malaria. Plasmodium parasites are thought to be restricted to hepatocytes throughout this obligate liver stage of development, and how liver-stage-expressed antigens prime productive CD8 T cell responses remains unknown. We found that a subset of liver-infiltrating monocyte-derived CD11c+ cells co-expressing F4/80, CD103, CD207, and CSF1R acquired parasites during the liver stage of malaria, but only after initial hepatocyte infection. These CD11c+ cells found in the infected liver and liver-draining lymph nodes exhibited transcriptionally and phenotypically enhanced antigen-presentation functions and primed protective CD8 T cell responses against Plasmodium liver-stage-restricted antigens. Our findings highlight a previously unrecognized aspect of Plasmodium biology and uncover the fundamental mechanism by which CD8 T cell responses are primed against liver-stage malaria antigens.

Active Cushing Disease Is Characterized by Increased Adipose Tissue Macrophage Presence.

CONTEXT: Although glucocorticoids (GCs) have potent anti-inflammatory actions, patients with hypercortisolism due to Cushing disease (CD) have increased circulating proinflammatory cytokines that may contribute to their insulin resistance and cardiovascular disease. The mechanisms and tissues that account for the increased systemic inflammation in patients with CD are unknown. OBJECTIVE: To determine whether chronic endogenous GC exposure due to CD is associated with adipose tissue (AT) inflammation in humans. DESIGN, SETTING, PARTICIPANTS: Abdominal subcutaneous AT samples from 10 patients with active CD and 10 age-, sex-, and body mass index‒matched healthy subjects were assessed for macrophage infiltration and mRNA expression of proinflammatory cytokines. MAIN OUTCOME MEASURE: Using immunohistochemistry, AT samples were analyzed for the expression of vimentin, caspase, CD3, CD4, CD8, CD11c, CD20, CD31, CD56, CD68, and CD163. Quantitative PCR was used to assess the mRNA gene expression of arginase, CD11b, CD68, EMR-1, IL-6, IL-10, MCP-1, and TNF-α. RESULTS: Immunohistochemistry revealed higher mean percentage infiltration of CD68+ macrophages and CD4+ T lymphocytes, increased mean area of CD11c+ M1 macrophages, higher number of CD11c+ crownlike structures, and decreased vimentin in the AT of patients with active CD compared with controls. PCR revealed no differences in mRNA expression of any analyzed markers in patients with CD. CONCLUSIONS: Chronic exposure to GCs due to CD increases the presence of AT macrophages, a hallmark of AT inflammation. Hence, AT inflammation may be the source of the systemic inflammation seen in CD, which in turn may contribute to obesity, insulin resistance, and cardiovascular disease in these patients.

Generation of a triple-fluorescent mouse strain allows a dynamic and spatial visualization of different liver phagocytes in vivo.

Resident and circulating immune cells have been extensively studied due to their almost ubiquitous role in cell biology. Despite their classification under the "immune cell department", it is becoming increasingly clear that these cells are involved in many different non-immune related phenomena, including fetus development, vascular formation, memory, social behavior and many other phenotypes. There is a huge potential in combining high-throughput assays - including flow cytometry and gene analysis - with in vivo imaging. This can improve our knowledge in both basic and clinical cell biology, and accessing the expression of markers that are relevant in the context of both homeostasis and disease conditions might be instrumental. Here we describe how we generated a novel mouse strain that spontaneously express three different fluorescence markers under control of well-studied receptors (CX3CR1, CCR2 and CD11c) that are involved in a plethora of stages of cell ontogenesis, maturation, migration and behavior. Also, we assess the percentage of the expression and co-expression of each marker under homeostasis conditions, and how these cells behave when a local inflammation is induced in the liver applying a cutting-edge technology to image cells by confocal intravital microscopy.

Increased susceptibility to oral Trichuris muris infection in the specific absence of CXCR5+ CD11c+ cells.

Trichuris muris is a natural mouse helminth pathogen which establishes infection specifically in the caecum and proximal colon. The rapid expulsion of T. muris in resistant mouse strains is associated with the induction of a protective T helper cell type 2 (Th2)-polarized immune response. Susceptible mouse strains, in contrast, mount an inappropriate Th1 response to T. muris infection. Expression of the chemokine CXCL13 by stromal follicular dendritic cells attracts CXCR5-expressing cells towards the B-cell follicles. Previous studies using a complex in vivo depletion model have suggested that CXCR5-expressing conventional dendritic cells (cDC) help regulate the induction of Th2-polarized responses. Here, transgenic mice with CXCR5 deficiency specifically restricted to CD11c+ cells were used to determine whether the specific absence CXCR5 on CD11c+ cells such as cDC would influence susceptibility to oral T. muris infection by affecting the Th1/Th2 balance. We show that in contrast to control mice, those which lacked CXCR5 expression on CD11c+ cells failed to clear T. muris infection and developed cytokine and antibody responses that suggested a disturbed Th1/Th2 balance with enhanced IFN-γ expression. These data suggest an important role of CXCR5-expressing CD11c+ cells such as cDC in immunity to oral T. muris infection.

Macrophages and Dendritic Cells Are the Predominant Cells Infected in Measles in Humans.

Characterization of human measles cases is essential in order to better assess the data generated in model systems of morbillivirus infection. To this end, we collected formalin-fixed tissue samples from 23 natural measles cases from different areas in the world and different phases of disease ranging from prodromal and acute measles to a persistent infection in an immunocompromised subject. We show that the vast majority of measles virus (MV)-infected cells in epithelia were intraepithelial immune cells that were, in most cases, positive for the CD11c myeloid cell marker. Small numbers of measles virus-infected cytokeratin-positive epithelial cells were also detected in bronchial and appendix epithelia. Dissolution and disruption of uninfected and MV-infected alveolar and bronchial epithelia were prominent features of the measles cases, especially in the established and late phases of the disease. In some instances, this was associated with the formation of MV-infected multinucleated giant cells which expressed CD11c and/or macrophage cell marker 68, a pathological feature also prominently observed in closely associated mucosa-associated lymphoid tissue. Collectively, these data show that resident and inflammatory infiltrating immune cells alter the architecture of respiratory tract epithelia and highlight the necessity for additional research into the function(s) and expression of nectin-4 in human tissues.IMPORTANCE We have brought together a unique collection of 23 human cases of measles infection and studied the types of cells that are infected. This work has not been done with modern technologies such as double labeling with antibodies and confocal microscopy in human cases primarily due to the fact that it is difficult to obtain the material because, fortunately, measles is fatal in only a very small fraction of infected patients. During the past decades, the receptors for measles virus have been elucidated and monkey models have been developed. We found that, in most cases, independently of whether the tissues were obtained early or later in the infection, the primary cell types that were infected were those of the immune system such as lymphocytes, macrophages, and dendritic cells. A very small number of epithelial cells were also found to be infected.

M1 macrophages decrease in the deciduae from normal pregnancies but not from spontaneous abortions or unexplained recurrent spontaneous abortions.

BACKGROUND/PURPOSE: To investigate the M1/M2 polarity of macrophages in the endometrium among different menstrual cycles, normal and abnormal pregnancies, and unexplained recurrent spontaneous abortions (RSAs). METHODS: Endometrial tissue was obtained from 43 patients undergoing hysterectomy, either in the follicular phase (Group 1, n = 23) or in the luteal phase (Group 2, n = 20). In addition, decidual tissue was obtained from 53 pregnant women during the first trimester, either of normal pregnancies (Group 3, n = 12) or abnormal pregnancies (Group 4: spontaneous abortions, n = 20; Group 5: unexplained RSA, n = 21). Using immunofluorescence to examine the M1 and M2 macrophages in the endometrium and deciduae from cases with different menstrual phases and various pregnancy outcomes, respectively, we endeavored to learn the possible pathophysiology of abortions. RESULTS: M1 macrophages were abundant in the deciduae of spontaneous abortions and unexplained RSA, whereas the frequency of M2 macrophages was significantly higher in the endometrium of luteal phase and normal pregnancies. CONCLUSION: M2 polarization is important for early successful pregnancies in humans.

[Response surface methodology for optimizing the technology of induction and isolation of dendritic cells by multiple cytokines].

Objective To promote the induction and separation efficiency of bone marrow-derived dendritic cells (BMDCs) in vitro through optimizing the inducing and isolating process by multiple cytokines. Methods The factors to be optimized in single factor tests included recombinant mouse granulocyte macrophage-colony stimulating factor (rmGM-CSF), recombinant mouse interleukine 4 (rmIL-4), lipopolysaccharide (LPS), recombinant mouse tumor necrosis factor α (rmTNF-α) and inducing time. The numbers of immature dendritic cells (imDCs) and mature dendritic cells (mDCs) were investigated as the indicators. Box-Behnken experimental design-response surface methodology was used to analyze and verify the data. Morphological changes were observed using the inverted microscopy and the transmission electron microscopy. Surface molecules including CD11c and CD86 were detected using the flow cytometry. Results The optimum inducing conditions for imDCs were obtained as follows: rmGM-CSF was 46 ng/mL, rmIL-4 was 24 ng/mL, inducing time was 6 days, and the number of imDCs was (4.58±0.28)×106 cells, and the relative deviation was 4.00%. The optimum inducing conditions for mDCs were as follows: LPS was 1.4 µg/mL, rmTNF-α was 30 ng/mL, inducing time was 1 day, and the number of mDCs was (4.21±0.15)×106 cells, and the relative deviation was 3.80%. Sufficient typical imDCs and mDCs were obtained within 5-7 days of induction in vitro. Also, flow cytometry showed that the amplified imDCs had a high expression of CD11c (68.62%±2.3%) and a low expression of CD86 (37.95%±1.8%), and the mDCs had high expressions of both CD86 (90.34%±1.4%) and CD11c (82.05%±1.6%). Conclusion The combination of single factor tests and Box-Behnken design -response surface methodology could optimize the inducing and isolating method for DCs in vitro by multiple cytokines rapidly and efficiently, which provided basic experiment materials for further studies.

Expression pattern of CD11c on lung immune cells after disseminated murine cytomegalovirus infection.

BACKGROUND: Cytomegalovirus (CMV) infection occurs frequently and is widespread globally. Numerous studies have shown that various types of immune cells play roles in mediating the response to CMV infection. CD11c, a commonly used dendritic cell (DC) marker, is expressed by other immune cells as well, such as T cells. This study analyzed the immune cells that express CD11c and monitored the expression level of their specific cell surface markers in the lung following a disseminated murine (M)CMV infection. METHODS: Mouse models of disseminated MCMV infection were used; uninfected and lipopolysaccharide (LPS)-treated mice were used as controls. At 1, 3 and 7 days following infection, single cell suspensions prepared from freshly digested lung tissue were stained for CD11c, CD86 and MHC II. Stained cells were analyzed using flow cytometry. Peripheral blood and single cell suspensions from spleen were sorted as well. Then these cells were subjected to analyze the CD11c expression pattern on natural killer (NK) cells and T cells. RESULTS: This assay showed that after MCMV infection, the expression of CD86 on pulmonary CD11chiMHC-IIhi cells (encompassing conventional DCs) was higher at 3 days post-infection than at 1 or 7 days post-infection, accompanied by a downregulation of MHC II. In addition, expression of CD11c was greatly increased in the MCMV infection group at 7 days post infection. This study also detected a large population of cells displaying an intermediate level of expression of CD11c (CD11cint); these cells were in the MCMV groups exclusively, and were subsequently identified as CD8+ T cells. In lung, spleen and blood, different proportions of CD11cint cells among the NK cell and T cell populations were observed between the BALB/c and C57BL/6 mice with or without MCMV infection. The expression level of NKp46 in NK cells dropped to a lower level after MCMV infection. CONCLUSIONS: The findings collectively indicate that CD11cintCD8+ T cells might play a key role in anti-MCMV adaptive immune response in lungs, as well as in spleen and blood. B220+CD11cint NK cells might be a more effective type of NK cell, participating in anti-MCMV infection. The downregulation of NKp46, in particular, might be linked with the immune evasion of MCMV.

Early Differentiation of Human CD11c+NK Cells with γδ T Cell Activation Properties Is Promoted by Dialyzable Leukocyte Extracts.

Reconstitution of the hematopoietic system during immune responses and immunological and neoplastic diseases or upon transplantation depends on the emergent differentiation of hematopoietic stem/progenitor cells within the bone marrow. Although in the last decade the use of dialyzable leukocyte extracts (DLE) as supportive therapy in both infectious and malignant settings has increased, its activity on the earliest stages of human hematopoietic development remains poorly understood. Here, we have examined the ability of DLE to promote replenishment of functional lymphoid lineages from CD34+ cells. Our findings suggest that DLE increases their differentiation toward a conspicuous CD56+CD16+CD11c+ NK-like cell population endowed with properties such as IFNy production, tumor cell cytotoxicity, and the capability of inducing γδ T lymphocyte proliferation. Of note, long-term coculture controlled systems showed the bystander effect of DLE-stromal cells by providing NK progenitors with signals to overproduce this cell subset. Thus, by direct effect on progenitor cells and through activation and remodeling of the supporting hematopoietic microenvironment, DLE may contribute a robust innate immune response by promoting the emerging lymphopoiesis of functional CD11c+ NK cells in a partially TLR-related manner. Unraveling the identity and mechanisms of the involved DLE components may be fundamental to advance the NK cell-based therapy field.

Differential Type I Interferon Signaling Is a Master Regulator of Susceptibility to Postinfluenza Bacterial Superinfection.

UNLABELLED: Bacterial superinfections are a primary cause of death during influenza pandemics and epidemics. Type I interferon (IFN) signaling contributes to increased susceptibility of mice to bacterial superinfection around day 7 post-influenza A virus (IAV) infection. Here we demonstrate that the reduced susceptibility to methicillin-resistant Staphylococcus aureus (MRSA) at day 3 post-IAV infection, which we previously reported was due to interleukin-13 (IL-13)/IFN-γ responses, is also dependent on type I IFN signaling and its subsequent requirement for protective IL-13 production. We found, through utilization of blocking antibodies, that reduced susceptibility to MRSA at day 3 post-IAV infection was IFN-ß dependent, whereas the increased susceptibility at day 7 was IFN-α dependent. IFN-ß signaling early in IAV infection was required for MRSA clearance, whereas IFN-α signaling late in infection was not, though it did mediate increased susceptibility to MRSA at that time. Type I IFN receptor (IFNAR) signaling in CD11c(+) and Ly6G(+) cells was required for the observed reduced susceptibility at day 3 post-IAV infection. Depletion of Ly6G(+) cells in mice in which IFNAR signaling was either blocked or deleted indicated that Ly6G(+) cells were responsible for the IFNAR signaling-dependent susceptibility to MRSA superinfection at day 7 post-IAV infection. Thus, during IAV infection, the temporal differences in type I IFN signaling increased bactericidal activity of both CD11c(+) and Ly6G(+) cells at day 3 and reduced effector function of Ly6G(+) cells at day 7. The temporal differential outcomes induced by IFN-ß (day 3) and IFN-α (day 7) signaling through the same IFNAR resulted in differential susceptibility to MRSA at 3 and 7 days post-IAV infection. IMPORTANCE: Approximately 114,000 hospitalizations and 40,000 annual deaths in the United States are associated with influenza A virus (IAV) infections. Frequently, these deaths are due to community-acquired Gram-positive bacterial species, many of which show increasing resistance to antibiotic therapy. Severe complications, including parapneumonic empyema and necrotizing pneumonia, can arise, depending on virulence factors expressed by either the virus or bacteria. Unfortunately, we are unable to control the expression of these virulence factors, making host responses a logical target for therapeutic interventions. Moreover, interactions between virus, host, and bacteria that exacerbate IAV-related morbidities and mortalities are largely unknown. Here, we show that type I interferon (IFN) expression can modulate susceptibility to methicillin-resistant Staphylococcus aureus (MRSA) infection, with IFN-ß reducing host susceptibility to MRSA infection while IFN-α increases susceptibility. Our data indicate that treatments designed to augment IFN-ß and/or inhibit IFN-α production around day 7 post-IAV infection could reduce susceptibility to deadly superinfections.

The impact of langerin (CD207)+ dendritic cells and FOXP3+ Treg cells in the small bowel mucosa of children with celiac disease and atopic dermatitis in comparison to children with functional gastrointestinal disorders.

In the present study we aimed to evaluate the impact of langerin (CD207)+ dendritic cells (DCs) and FOXP3+ Treg cells in the intestinal mucosa of children with celiac disease (CD) and atopic dermatitis (AD) in comparison to children with functional gastrointestinal disorders (FGD). Seventy-five children (37 male, mean age 8.4 ± 4.8 years), who randomly underwent small bowel biopsy, were studied. The CD was diagnosed in 14 children, including five persons with concomitant AD (all positive for anti-tissue transglutaminase IgA antibodies and with small bowel atrophy). Normal small bowel mucosa was found in eight patients with AD and in 53 patients with FGD. The sera of all patients were tested for total and specific IgE antibodies to food allergen panels. Staining for CD11c+, langerin (CD207+) DCs, CD4+, and FOXP3+ Treg cells was performed on paraffin-embedded sections of bioptates using immunohistochemistry. The density of CD11c+ DCs, CD4+, and FOXP3+ Treg cells was higher in the CD patients compared to the AD and FGD patients (p = 0.02; p = 0.001). In AD, significantly higher density of CD11c+ DCs was detected in patients positive for specific IgE to food allergen panels (p = 0.02). The FGD patients with elevated total IgE had increased density of langerin (CD207)+ DCs compared to the patients with normal total IgE levels (p = 0.01). The increased density of FOXP3+ Treg cells, CD4+, cells and CD11c+ DCs was associated with CD but not with AD. The elevated level of total IgE or specific IgE to food allergens was associated with more pronounced expression of DCs, indicating a possible link between the presence of these cells in small bowel mucosa with elevated level of serum IgE.

Ablating the aryl hydrocarbon receptor (AhR) in CD11c+ cells perturbs intestinal epithelium development and intestinal immunity.

Diet and microbiome derived indole derivatives are known to activate the ligand induced transcription factor, the Aryl hydrocarbon Receptor (AhR). While the current understanding of AhR biology has confirmed its role in mucosal lymphocytes, its function in intestinal antigen presenting cells (APCs) is poorly understood. Here, we report that Cre-mediated deletion of AhR in CD11c-expressing cells in C57/BL6 mice is associated with altered intestinal epithelial morphogenesis in vivo. Moreover, when co-cultured with AhR-deficient DCs ex vivo, intestinal organoids showed reduced SRY (sex determining region Y)-box 9 and increased Mucin 2 expression, which correlates with reduced Paneth cells and increased goblet cell differentiation, similar to the data obtained in vivo. Further, characterization of intestinal APC subsets, devoid of AhR, revealed an expression pattern associated with aberrant intrinsic Wnt pathway regulation. At a functional level, the loss of AhR in APCs resulted in a dysfunctional epithelial barrier, associated with a more aggressive chemically induced colitis compared to wild type animals. Our results are consistent with a model whereby the AhR signalling pathway may participate in the regulation of innate immunity through intestinal epithelium development and mucosal immunity.

Antigen presenting cell abnormalities in the Cln3(-/-) mouse model of juvenile neuronal ceroid lipofuscinosis.

Mutations of the CLN3 gene lead to juvenile neuronal ceroid lipofuscinosis (JNCL), an autosomal recessive lysosomal storage disorder that causes progressive neurodegeneration in children and adolescents. There is evidence of immune system involvement in pathology that has been only minimally investigated. We characterized bone marrow stem cell-derived antigen presenting cells (APCs), peritoneal macrophages, and leukocytes from spleen and blood, harvested from the Cln3(-/-) mouse model of JNCL. We detected dramatically elevated CD11c surface levels and increased total CD11c protein in Cln3(-/-) cell samples compared to wild type. This phenotype was specific to APCs and also to a loss of CLN3, as surface levels did not differ from wild type in other leukocyte subtypes nor in cells from two other NCL mouse models. Subcellularly, CD11c was localized to lipid rafts, indicating that perturbation of surface levels is attributable to derangement of raft dynamics, which has previously been shown in Cln3 mutant cells. Interrogation of APC function revealed that Cln3(-/-) cells have increased adhesiveness to CD11c ligands as well as an abnormal secretory pattern that closely mimics what has been previously reported for Cln3 mutant microglia. Our results show that CLN3 deficiency alters APCs, which can be a major contributor to the autoimmune response in JNCL.

[Dexamethason suppresses the activation of rat microglia induced by glutamic acid].

OBJECTIVE: To investigate the effect of dexamethasone (DEX) on the microglia activation induced by glutamic acid (GLU) in rats. METHODS: We isolated and cultured the microglia from the spinal cord of SD infant rats in vitro. The cell purity was tested by immunofluorescence technique. The cells were then randomly divided into 5 groups: Dulbecco' s phosphate buffered saline treatment (DPBS group); GLU treatment (GLU group); DEX pretreatment and then GLU stimulation; simultaneous treatment of DEX and GLU; GLU stimulation followed by DEX treatment. Finally, immunofluorescence technique was used to investigate the expressions of glucocorticoid receptor (GR) and CD11b/c protein. RESULTS: Compared with the DPBS group, GLU group presented the increased expression of CD11b/c protein, the shorten length of cell processes as well as cell shape turning round. Furthermore, compared with the GLU group, the CD11b/c protein expression significantly decreased in the group treated simultaneously with DEX and GLU and the group treated with DEX after GLU stimulation. However, the expression was not different between the GLU group and the group treated with DEX and then stimulated by GLU. CONCLUSION: DEX could inhibit microglia activation induced by GLU, while DEX pretreatment have no such an effect on microglia.

Gatekeeper role of brain antigen-presenting CD11c+ cells in neuroinflammation.

Multiple sclerosis is the most frequent chronic inflammatory disease of the CNS. The entry and survival of pathogenic T cells in the CNS are crucial for the initiation and persistence of autoimmune neuroinflammation. In this respect, contradictory evidence exists on the role of the most potent type of antigen-presenting cells, dendritic cells. Applying intravital two-photon microscopy, we demonstrate the gatekeeper function of CNS professional antigen-presenting CD11c(+) cells, which preferentially interact with Th17 cells. IL-17 expression correlates with expression of GM-CSF by T cells and with accumulation of CNS CD11c(+) cells. These CD11c(+) cells are organized in perivascular clusters, targeted by T cells, and strongly express the inflammatory chemokines Ccl5, Cxcl9, and Cxcl10. Our findings demonstrate a fundamental role of CNS CD11c(+) cells in the attraction of pathogenic T cells into and their survival within the CNS. Depletion of CD11c(+) cells markedly reduced disease severity due to impaired enrichment of pathogenic T cells within the CNS.

Dendritic cell chimerism in oral mucosa of transplanted patients affected by graft-versus-host disease.

OBJECTIVE: Graft-versus-host disease (GVHD) is one of the main complications after haematopoietic stem cell transplantation. Clinical features of GVHD include either an acute (aGVHD) or a chronic (cGVHD) condition that affects locations such as the oral mucosa. While the involvement of the host's dendritic cells (DCs) has been demonstrated in aGVHD, the origin (donor/host) and mechanisms underlying oral cGVHD have not been completely elucidated. In this study, we intend to determine the origin of DCs present in mucosal tissue biopsies from the oral cavity of transplanted patients affected by cGVHD. METHODS: We purified DCs, from oral biopsies of three patients with cGVHD, through immunobeads and subsequently performed DNA extraction. The origin of the obtained DCs was determined by PCR amplification of 13 informative short tandem repeat (STR) alleles. We also characterised the DCs phenotype and the inflammatory infiltrate from biopsies of two patients by immunohistochemistry. RESULTS: Clinical and histological features of the biopsies were concordant with oral cGVHD. We identified CD11c-, CD207- and CD1a-positive cells in the epithelium and beneath the basal layer. Purification of DCs from the mucosa of patients affected by post-transplantation cGVHD was >95%. PCR-STR data analysis of DCs DNA showed that 100% of analysed cells were of donor origin in all of the evaluated patients. CONCLUSION: Our results demonstrate that resident DCs isolated from the oral tissue of allotransplanted patients affected by cGVHD are originated from the donor. Further research will clarify the role of DCs in the development and/or severity of oral cGVHD.