Immature Myeloid Dendritic Cells Research Articles

Cytohistological Correlation of Langerhans Cell Histiocytosis of the Spine in a Young Adult

Langerhans cell histiocytosis (LCH) is a rare multisystem disorder with a common histopathological finding of Langerhans-type cell proliferation mixed with a milieu of inflammatory cells. Bone involvement is a common presentation occurring in children and young adults. Recent studies using cell-specific gene expression profiling suggest that LCH arises from bone marrow-derived immature myeloid dendritic cells. We present a case of solitary LCH of cervical vertebrae in a young adult with pain and numbness in the shoulder diagnosed on fine-needle aspiration and confirmed on histopathology and immunohistochemistry. It was treated with tumor resection and stabilization of the vertebrae.

Rare Genetic Disorders Affecting the Periodontal Supporting Tissues in Adolescence

In adolescents periodontal destruction may be the primary manifestation of an as yet unrecognized rare systemic disease, and it may be up to the periodontist to make the correct tentative diagnosis. Many genetic diseases that present with primary periodontal manifestations in adolescence affect immune function, sometimes with only mild or absent systemic features. They include periodontal Ehlers-Danlos syndrome (lack of attached gingiva, various connective tissue abnormalities), Papillon-Lefèvre syndrome (palmoplantar hyperkeratosis), and plasminogen deficiency (fibrin deposition within mucous membranes). Other immune disorders with severe periodontitis manifesting in adolescence are usually diagnosed in early childhood due to unmistakeable systemic features. They include Cohen syndrome (developmental disorder, truncal obesity, and microcephaly), Hermansky-Pudlak Syndrome (oculocutaneous albinism, bleeding diathesis, and other systemic manifestations), glycogen storage disease type 1b, and Chediak-Higashi syndrome (pyogenic infections, albinism, and neuropathy). The structural integrity of periodontal tissue is affected in genodermatoses such as Kindler syndrome, a type of epidermolysis bullosa. In primary hyperoxaluria, inflammatory periodontal destruction is associated with renal calculi. Breakdown of periodontal tissues independent of dental plaque biofilm-induced periodontitis is found in hypophosphatasia (highly variable skeletal hypomineralization) or isolated odontohypophosphatasia, hypophosphatemic rickets and primary hyperparathyroidism. Finally, alveolar osteolysis mimicking localized periodontitis may be due to neoplastic processes, e.g., in neurofibromatosis type 1 (typical skin features including café au lait macules and neurofibromas), Langerhans cell histiocytosis (locally destructive proliferation of bone marrow-derived immature myeloid dendritic cells), and Gorham-Stout disease (diffuse cystic angiomatosis of bone).

Long-term complications in uniformly treated paediatric Langerhans histiocytosis patients disclosed by 12 years of follow-up of the JLSG-96/02 studies.

Langerhans cell histiocytosis (LCH) is a rare inflammatory myeloid neoplasia derived from immature myeloid dendritic cells with the mitogen-activated protein kinase (MAPK) pathway gene mutation. LCH is rarely fatal, but patients develop various permanent consequences (PCs). We report the frequencies of LCH-related PCs in paediatric patients (n=317) treated by the JLSG-96/02 AraC-containing regimens. One-third of LCH patients had at least one PC at a median follow-up of 12years. Central nervous system (CNS)-related PCs (neurological and endocrinological) accounted for 21·5%, non-CNS-related 16·7%. We require novel therapeutic measures to further reduce the frequency of LCH-related PCs.

Oral manifestations of Langerhans cell histiocytosis with unusual histomorphologic features

Langerhans cell histiocytosis (LCH) is a bone marrow-derived immature myeloid dendritic cell proliferative disorder with diverse clinical manifestations commonly involves bone, skin, lymph node and lung. Oral involvement is uncommon. Intraoral lesions can be the first sign of either a localized LCH or clinically undiagnosed systemic LCH, predates systemic manifestations of LCH, or an early indicator of recurrence in known cases. Clinically, it can be mistaken for primary oral and dental inflammatory, infectious and neoplastic lesions. Histologically, diagnostic challenges may arise because of the nature of oral and dental specimens, different tissue reaction patterns and variations in histomorphology of LCH. We performed a retrospective review study over 10 years. We searched for diagnosed cases of LCH. We retrieved and reviewed cases of LCH with oral involvement. We found 54 cases of LCH, four (7.4%) with oral involvement. The age range was between 1 and 27 years with an average age of 13.7 years. They were males. They were clinically confused with abscess, cysts, infection, granulation tissue and other neoplastic lesions. Histologically, they showed different histopathologic features including different patterns of necrosis, granulomas, allergic-like inflammation, superimposed infection, stomatitis, cyst and sinus formation, foreign body giant cell reaction, and foci mimicking lymphomas and metastasis. Certain cytologic features were helpful hints. In doubtful cases, immunohistochemistry helped confirm the diagnosis. Because of the multiple fragmented nature of oral specimens with different tissue reaction patterns, the diagnostic Langerhans cells may be missed or misinterpreted. Oral LCH may be confused with infectious, inflammatory, benign and malignant neoplastic lesions because of its variable clinical presentations and its heterogeneous histomorphologic features. Pathologists have an important role in guiding clinicians to the correct diagnosis and patients' management. They should be familiar with the different histomorphologic patterns to avoid pitfalls. Attention to certain morphologic features and immunohistochemistry should help resolve challenging cases.

Multisystem Langerhans cell histiocytosis in an infant: A case report and review of literature

Langerhans cell histiocytosis (LCH) is a rare disease of childhood which originates from marrow-derived immature myeloid dendritic cells of skin and visceral organs with incompletely understood etiopathogenesis. An 11-month-old infant presented with fever, pallor, multiple erythematous, crusted, scaly hypopigmented macules, and shiny colored papules over scalp, forehead, and trunk along with hepatosplenomegaly. Persistent pancytopenia, punched out lesion on a brain scan, and multinucleated giant cells with eosinophilic cytoplasm admixture with eosinophils and lymphocytes on skin biopsy were seen. Immunohistochemistry was positive for CD1a and S100. The patient was treated with vinblastine and steroid, but unfortunately parents did not complete the therapy. A high index of suspicion is necessary to make timely diagnosis and therapy to minimize the frustration felt by parents/patients.

Abstract 5092: ZVex® lentiviral vector strongly activates pro-inflammatory, antigen processing, and anti-viral defense response pathways in monocyte-derived dendritic cells

Abstract Background: Dendritic cells (DCs) are professional antigen presenting cells that effectively bridge the innate and adaptive immune responses and require activation for successful priming of naïve T-cells. We have developed ZVex, an integration deficient, hybrid lentiviral vector engineered to target DC-SIGN expressed on immature myeloid DCs for genetic immunization against tumor antigens. As lentiviruses normally don't efficiently infect DCs, little is known about the functional effect of LV transduction of conventional DCs. Here, the effect of DC transduction with ZVex vectors was studied by gene expression profiling. Material and Methods: Human moDCs from multiple donors were prepared by 5-day stimulation with IL-4 and GM-CSF and transduced with ZVex-GFP or control vectors, such as a ZVex with nonfunctional reverse transcriptase (RT-dead), ZVex particles generated to contain no vector genome (empty ZVex), and a heat-inactivated ZVex preparation. Cellular RNA was isolated at different time points from transduced DC cultures and used for gene expression profiling with Nanostring’s human pan cancer immune panel (770 genes). Results: DCs transduced with ZVex vectors displayed statistically significant up-regulation of genes involved in pro-inflammatory, antigen processing, and anti-viral defense pathways. Noteworthy among the up-regulated genes were classical anti-viral response genes like OAS3, MX1, and interferon stimulated genes like ISG15 and ISG20. Incubation with the RT-dead mutant vector also led to up-regulation of these genes, albeit to a much lower extent, suggesting that LV-RNA itself can result in the activation of these pathways in DCs, though reverse transcription appears to further potentiate the response. Of note, cells transduced with empty ZVex, which consists of an intact virion particle but lacks encapsulated LV RNA, also mediated a low magnitude and breadth of DC transcriptional activation, possibly via signaling through DC-SIGN. Conclusions: ZVex incorporates several elements capable of inducing a potent innate immune activation in DCs. DCs are relatively insensitive to lentiviral infection, but the use of accessory proteins in ZVex makes DCs conducive to ZVex transduction and results in the induction of a Type-1 IFN response that seems to be largely dependent on reverse transcription. In addition, other engineered vector particle components such as non-reverse transcribed viral RNA, viral structural proteins, and/or engagement of the DC-SIGN receptor, also contribute to DC activation. Citation Format: Anshika Bajaj, Lisa Y. Ngo, Peter Berglund, Jan ter Meulen. ZVex® lentiviral vector strongly activates pro-inflammatory, antigen processing, and anti-viral defense response pathways in monocyte-derived dendritic cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5092. doi:10.1158/1538-7445.AM2017-5092

The Chemerin/ChemR23 Axis Plays a Pivotal Role in the Pathogenesis of Intestinal Damage in a Murine Model of Graft Versus Host Disease

Allogeneic haematopoietic-stem-cell transplantation (HSCT) is the treatment of choice for many malignant and non-malignant disorders. However, Graft-versus -Host Disease (GvHD), the major complication of allogeneic HSCT, limits its wider application. Among different sites that can be involved, gastrointestinal GvHD represents the major cause of patients morbidity and mortality.The infiltration of different cell subsets into target organs is an important step in GvHD pathogenesis, and the modulation of cell trafficking could represent a promising strategy for GvHD prophylaxis and treatment. Chemerin has been recently identified as a chemotactic protein, which is produced by several tissues during inflammation and binds the G protein-coupled receptor ChemR23, expressed by immature myeloid and plasmacytoid Dendritic Cells, macrophages and natural killer cells.The aim of this study was to evaluate the potential role of Chemerin/ChemR23 axis in the pathogenesis of GvHD, in order to identify disease-specific pathways exploitable for developing new potential therapeutic targets. For this purpose, lethally irradiated Balb/C recipient mice were transplanted with bone marrow cells and splenocytes obtained from ChemR23deficient (ChemR23-/-) C57BL6 mice. After transplantation, mice were monitored daily for survival and GvHD severity. Recipient mice were sacrificed at different time points to evaluate Chemerin production and leukocytes infiltration in skin, lung, liver, and gut by using different techniques, such as ELISA, histopathology, FACS and PCR.Starting from day +6 after transplantation, Chemerin plasma levels appeared significantly higher in both wild type (WT) and ChemR23-/- mice who developed GvHD (WT mean level=86.8 ng/ml; range=80.1-91.9; ChemR23-/- mean level=83.8 ng/ml; range=70.5-103.6, n=6, day+7) compared to syngeneic controls (mean level=62.8 ng/ml; range=49.2-82.5, n=6, day+7), p=0.02. Interestingly, ChemR23-/- mice developed a more severe GvHD compared to mice transplanted with WT cells. In particular, ChemR23-/- transplantedmice showed a higher mortality rate (at day +28 after HSCT: 85% mortality in ChemR23-/- vs 25% in WT, p=0.0004, n=45) (Fig. 1). Differences in GvHD score between ChemR23-/- and WT transplanted mice resulted by a significantly increase in weight loss, associated to severe diarrhea. In accordance, histopathologic analysis performed on GvHD target organs showed a significantly higher GvHD score in large intestine of ChemR23-/- transplanted mice, whereas no differences were found in other GvHD target organs. In addition, a deeper histological analysis on large intestine showed that tissue damage is characterized by crypt hyperplasia and atrophy, epithelium apoptosis and colitis. Moreover, FACS analysis of large intestine infiltrating leukocytes showed an higher neutrophils frequency in ChemR23-/- transplantedmice compared to WT (neutrophils=10.39%, range 6.5%-15.1% versus neutrophils=5.84%, range 2.6%-12.8%, respectively, p=0.001, n=10). This observation was also obtained by analyzing the mesenteric lymphnode. The higher neutrophils infiltration was also confirmed by immunohistochemistry evaluating the number of myeloperoxidase (MPO) positive cells and by quantitative PCR detecting MPO expression (ChemR23-/- mean 2-ΔΔCt =22.35, range 2.43-46.05; WT mean 2-ΔΔCt =6.42, range 0.20-19.23; p=0.04, n=8).All these findings suggest that the Chemerin/ChemR23 axis play a crucial role in intestinal GVHD. Further studies are needed to better understand the mechanisms underling the severe damage observed in the gastrointestinal tract of mice transplanted with ChemR23-/- cells. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Immunodetection of myeloid and plasmacytoid dendritic cells in mammary carcinomas of female dogs

ABSTRACT: Dendritic cells have attracted great interest from researchers as they may be used as targets of tumor immune evasion mechanisms. The main objective of this study was to evaluate the relationship between the dendritic cells (DCs) subpopulation in simple type mammary carcinomas in female dogs. Two groups of samples were used: the control group consisted of 18 samples of mammary tissue without changes and the tumor group with 26 simple type mammary carcinomas. In these groups, we evaluated the immunodetection of immature and mature myeloid DCs, plasmacytoid DCs and MHC-II. In mammary tumor, mature myeloid DCs predominated in the peritumoral region, while immature myeloid DCs and plasmacytoid DCs were evident in the intratumoral region. Immunostaining of MHC-II was visualized in mammary acini (control group), in tumor cells and inflammatory infiltration associated with tumors. The comparison between the control and tumor groups showed a statistically significant difference between immature myeloid DCs, mature myeloid DCs and plasmacytoid DCs. The immunodetection of MHC-II was not significant when comparing the groups. The predominance of immature DCs in the tumor group is possibly related to an inefficient immune response, promoting the development and survival of tumor cells. The presence of plasmacytoid DCs in the same group suggests a worse prognosis for female dogs with mammary tumors. Therefore, the ability of differentiation of canine dendritic cells could be influenced by neoplastic cells and by the tumor microenvironment.

A core of kinase-regulated interactomes defines the neoplastic MDSC lineage.

Myeloid-derived suppressor cells (MDSCs) differentiate from bone marrow precursors, expand in cancer-bearing hosts and accelerate tumor progression. MDSCs have become attractive therapeutic targets, as their elimination strongly enhances anti-neoplastic treatments. Here, immature myeloid dendritic cells (DCs), MDSCs modeling tumor-infiltrating subsets or modeling non-cancerous (NC)-MDSCs were compared by in-depth quantitative proteomics. We found that neoplastic MDSCs differentially expressed a core of kinases which controlled lineage-specific (PI3K-AKT and SRC kinases) and cancer-induced (ERK and PKC kinases) protein interaction networks (interactomes). These kinases contributed to some extent to myeloid differentiation. However, only AKT and ERK specifically drove MDSC differentiation from myeloid precursors. Interfering with AKT and ERK with selective small molecule inhibitors or shRNAs selectively hampered MDSC differentiation and viability. Thus, we provide compelling evidence that MDSCs constitute a distinct myeloid lineage distinguished by a "kinase signature" and well-defined interactomes. Our results define new opportunities for the development of anti-cancer treatments targeting these tumor-promoting immune cells.

A novel potential therapy for vascular diseases: blood‐derived stem/progenitor cells specifically activated by dendritic cells

Vascular diseases are a major cause of morbidity and mortality, particularly in diabetic patients. Stem/progenitor cell treatments with bone marrow-derived cells show safety and promising outcomes, albeit not without some preprocedural adverse events related to cell collection and mobilization. We describe a novel technology for generating a therapeutic population (BGC101) of enriched endothelial progenitor cells (EPCs) from non-mobilized blood, using dendritic cells to specifically direct stem/progenitor cell activity in vitro. Selected immature plasmacytoid and myeloid dendritic cells from 24 healthy and two diabetic donors were activated with anti-inflammatory and pro-angiogenic molecules to induce specific activation signals. Co-culturing of activated dendritic cells with stem/progenitor cells for 12-66 h generated 83.7 ± 7.4 × 10(6) BGC101 cells with 97% viability from 250 mL of blood. BGC101, comprising 52.4 ± 2.5% EPCs (expressing Ulex-lectin, AcLDL uptake, Tie2, vascular endothelial growth factor receptor 1 and 2, and CD31), 16.1 ± 1.9% stem/progenitor cells (expressing CD34 and CD184) and residual B and T helper cells, demonstrated angiogenic and stemness potential and secretion of interleukin-8, interleukin-10, vascular endothelial growth factor and osteopontin. When administered to immunodeficient mice with limb ischemia (n = 40), BGC101 yielded a high safety profile and significantly increased blood perfusion, capillary density and leg function after 21 days. Cell tracking and biodistribution showed that engraftment was restricted to the ischemic leg. These observations provide preliminary evidence that alternatively activated dendritic cells can promote the generation of EPC-enriched stem/progenitor cells within a 1-day culture. The resulting product BGC101 has the potential for treatment of various vascular conditions such as coronary heart disease, stroke and peripheral ischemia.

Accumulation of functionally immature myeloid dendritic cells in lymph nodes of rhesus macaques with acute pathogenic simian immunodeficiency virus infection

Myeloid dendritic cells (mDC) are key mediators of innate and adaptive immunity to virus infection, but the impact of HIV infection on the mDC response, particularly early in acute infection, is ill-defined. We studied acute pathogenic simian immunodeficiency virus (SIV) infection of rhesus macaques to address this question. The mDC in blood and bone marrow were depleted within 12 days of intravenous infection with SIVmac251, associated with a marked proliferative response. In lymph nodes, mDC were apoptotic, activated and proliferating, despite normal mDC numbers, reflecting a regenerative response that compensated for mDC loss. Blood mDC had increased expression of MHC class II, CCR7 and CD40, whereas in lymph nodes these markers were significantly decreased, indicating that acute infection induced maturation of mDC in blood but resulted in accumulation of immature mDC in lymph nodes. Following SIV infection, lymph node mDC had an increased capacity to secrete tumour necrosis factor-α upon engagement with a Toll-like receptor 7/8 ligand that mimics exposure to viral RNA, and this was inversely correlated with MHC class II and CCR7 expression. Lymph node mDC had an increased ability to capture and cleave soluble antigen, confirming their functionally immature state. These data indicate that acute SIV infection results in increased mDC turnover, leading to accumulation in lymph nodes of immature mDC with an increased responsiveness to virus stimulation.

Gonadotropin stimulation in mice leads to ovarian accumulation of immature myeloid cells and altered expression of proangiogenic genes

ObjectiveOvarian hyperstimulation syndrome is associated with increased angiogenesis and vascular leakage. Immature myeloid cells (IMCs) and dendritic cells have been shown to be actively involved in angiogenesis in several disease models in mice and humans. Nevertheless, little is known about the role of these cells in the ovary. As such, this study sought to determine whether alterations in these ovarian myeloid cell populations are associated with gonadotropin stimulation in a mouse model. Study designFour-week-old pre-pubertal C57Bl/6 female mice were allocated into three groups: high-dose stimulation (n=4; pregnant mare serum gonadotropins (PMSG) 20U for 2 days), low-dose stimulation (n=5; PMSG 5U for 1 day) and sham-treated controls (n=4). Human chorionic gonadotropin 5U was injected on Day 3, and the mice were killed on Day 5. Ovaries were analysed by flow cytometry, confocal microscopy and quantitative polymerase chain reaction. ResultsGonadotropin stimulation increased the proportion of CD11b+Gr1+ IMCs among the ovarian myeloid cells: 22.6±8.1% (high dose), 7.2±1.6% (low dose) and 4.1±0.3% (control) (p=0.02). Conversely, gonadotropin stimulation decreased the proportion of ovarian CD11c+MHCII+ dendritic cells: 15.1±1.9% (high dose), 20.7±4.8% (low dose) and 27.3±8.2% (control) (p=0.02). IMCs, unlike dendritic cells, were localized adjacent to PECAM1+ endothelial cells. Finally, gonadotropin stimulation was associated with increased expression of S100A8, S100A9, Vcan and Dmbt1, and decreased expression of MMP12. ConclusionsGonadotropin stimulation is associated with proangiogenic myeloid cell alterations, reflected by a dose-dependent increase in ovarian IMCs and a parallel decrease in dendritic cells. Recruited IMCs localize strategically at sites of angiogenesis. These changes are associated with differential expression of key proangiogenic genes.

Gonadotropin stimulation in mice leads to ovarian accumulation of proangiogenic immature myeloid cells and to altered expression of key proangiogenic genes

We sought to determine whether gonadotropin stimulation leads to alterations in ovarian pronagiogenic myeloid cells: immature myeloid cells (IMCs) and dendritic cells (DCs), and whether it is associated with differential pronagiogenic gene expression.

Dynamics of T-cell infiltration during the course of ovarian cancer: The gradual shift from a Th17 effector cell response to a predominant infiltration by regulatory T cells.

e22129 Background: Ovarian cancer is diagnosed in more than 190,000 new patients every year and is known to have the highest mortality rate among gynaecologic cancers. The type of immune cells that are present within the tumor microenvironment can play a crucial role in the survival of patients. However, little is known about the dynamics of the tumor-infiltrating immune cells during disease progression. Methods: We studied the immune cells infiltrating the tumor tissue of ovarian cancer patients at different stages of disease. We analysed the patterns of T lymphocytes in fresh tumor tissue as well as blood samples of 44 newly diagnosed ovarian cancer patients by flow cytometry. To evaluate whether regulatory T cells (Tregs) develop in situ or migrate to tumor tissue, we measured a concentration of chemokine CCL22 in tumor cell culture supernatants. We also determined the expression of CCR4 on circulating as well as tumor-infiltrating Tregs by flow cytometry. Results: The early stages of development of ovarian carcinomas were characterized by a strong Th17 immune response, whereas in stage II patients, recruitment of high numbers of Th1 cells was observed. In disseminated tumors (stage III-IV), we detected a dominant population of Helios+ activated regulatory T cells along with high numbers of macrophages and immature myeloid dendritic cells. Tumor-infiltrating Tregs had markedly lower expression of CCR4 than circulating Tregs, and the numbers of tumor-infiltrating Tregs significantly correlated with the levels of CCL22 in ovarian tumor cell culture supernatants, suggesting their recruitment via a CCR4/CCL22 interaction. CCL22 was mainly produced by tumor cells, macrophages and mDCs in the primary ovarian tumors, and its expression markedly increased in response to IFNgamma. Conclusions: Taken together, the specific recruitment of Tregs, probably triggered by inflammatory stimuli, leads to a significant immune suppression in the advanced stages of ovarian cancer.

Langerhans Cell Histiocytosis: Back to Histiocytosis X

Abstract SCI-8Langerhans cell histiocytosis (LCH) is a disorder characterized by inflammatory lesions that include pathologic CD207+ dendritic cells. LCH has pleotropic clinical presentations ranging from single lesions cured by curettage to potentially fatal multisystem disease. The first descriptions of LCH, including Hand-Schüller-Christian disease and Letterer-Siwe disease, were based on anatomic location and extent of the lesions. Despite clinical heterogeneity, LCH lesions are generally indistinguishable by histology, which led to the notion that the spectrum of clinical manifestations represents a single disorder, histiocytosis X. The designation “Langerhans cell histiocytosis” was subsequently proposed with discovery of cytoplasmic Birbeck granules in the pathologic infiltrating dendritic cells in histiocytosis X lesions, a feature shared by epidermal Langerhans cells. The etiology of LCH remains elusive, and debate of LCH as an inflammatory versus malignant disorder remains unresolved. However, recent discoveries question the model of LCH arising from transformed or pathologically activated epidermal Langerhans cells. We found cell-specific gene expression signature in CD207+ dendritic cells within LCH lesions to be more consistent with immature myeloid dendritic cell precursors than epidermal Langerhans cells. Furthermore, recent mouse studies demonstrate that CD207+ is more promiscuous than previously appreciated. Langerin (CD207) expression can be induced in many dendritic cell lineages, supporting the plausibility of a spectrum of candidates for an LCH cell of origin, including circulating dendritic cell precursors. Finally, recurrent activating BRAF mutations in LCH lesions suggest a role for a hyperactive RAS pathway in LCH pathogenesis, and possibly in normal dendritic cell development. This presentation will discuss the historical background and recent advances in LCH biology, along with a proposal to reframe “histiocytosis X” as a myeloid neoplasia caused by aberrant maturation and migration of myeloid dendritic cell precursors. Disclosures:No relevant conflicts of interest to declare.

The Expressions of Co‐Stimulatory Molecules are Altered on Putative Antigen‐Presenting Cells in Cord Blood

The aim of our study was to estimate the expressions of both B7-H1 and B7-H4 as well as CD200 and CD200R co-stimulatory molecules on immature myeloid and lymphoid dendritic cells, B CD19(+) lymphocytes and monocytes in umbilical cord blood of healthy neonates and in peripheral blood of healthy adults. Thirty-nine healthy full-term neonates from physiological single pregnancies and 27 healthy adults were included in the study. The expressions of B7-H1, B7-H4, CD200, CD200R antigens were estimated using flow cytometry. Statistical analysis was performed using a non-parametric Mann-Whitney U-test and parametric Wilcoxon's test. The expressions of B7-H1 and B7-H4 molecules on immature BDCA-1(+) myeloid dendritic cells were significantly lower in umbilical cord blood of healthy neonates when compared with those cells in peripheral blood of healthy adults (P<0.0001). Furthermore, the suppression of B7-H4 molecule on BDCA-2(+) lymphoid dendritic cells was observed in cord blood of healthy neonates when compared with peripheral blood of healthy adults (P<0.02). The expressions of CD200 antigen on BDCA-1(+) cells, CD200R antigen on BDCA-2(+) cells and CD200R antigen on B CD19(+) cells were significantly lower in cord blood of healthy neonates. On the other hand, the expressions of CD200 and CD200R as well as B7-H4 co-stimulatory molecules on CD14(+) cells were significantly higher in cord blood when compared with peripheral blood. The increased percentages of CD14(+) monocytes with the expressions of CD200 and CD200R as well as B7-H4 co-stimulatory molecules can suggest the increased immunomodulatory properties of neonatal monocytes in cord blood.

Cucurbitacin B Regulates Immature Myeloid Cell Differentiation and Enhances Antitumor Immunity in Patients with Lung Cancer

The aberrant activation of the JAK2/STAT3 signaling in immature myeloid dendritic cells (DCs) is associated with immune tolerance and poor antitumor immunity. The objective of this study was to test the hypothesis that Cucurbitacin B (CuB), a selective inhibitor of JAK2/STAT3 signaling, could promote DC differentiation and improve antitumor immunity. Twelve patients with advanced lung cancers were treated orally with CuB daily for 7 consecutive days. The frequency of peripheral blood myeloid DCs and immature myeloid cells (imCs) in those patients and healthy controls was characterized longitudinally by flow cytometry. The effect of CuB on the differentiation of DCs and p53-specific T responses was evaluated in vitro. The percentages of Lin(-)DR(-)CD33(+) imCs and Lin(-)DR(+)CD33(+) DCs were significantly different between patients with lung cancers and healthy controls (1.55% vs. 0.82%, p=0.002; 0.60% vs. 1.90%, p=0.000). Treatment with CuB significantly increased the frequency of Lin(-)DR(+)CD33(+), but reduced the frequency of Lin(-)DR(-)CD33(+) in patients with lung cancers (p<0.05). Treatment with CuB induced the differentiation of DCs cocultured with tumor cells 16HBE/BPDE and enhanced the sensitivity of 16HBE/BPDE cells to p53-specific CTL by inhibiting the JAK2/STAT3 activation, but also enhancing the interferon-γ-related STAT1 activation in 16HBE/BPDE cells. CuB significantly reduced the frequency of imCs in patients with lung cancers and enhanced the effect of p53-specific CTL on tumor 16HBE/BPDE cells.

Nogo receptor is involved in the adhesion of dendritic cells to myelin

BackgroundNogo-66 receptor NgR1 and its structural homologue NgR2 are binding proteins for a number of myelin-associated inhibitory factors. After neuronal injury, these inhibitory factors are responsible for preventing axonal outgrowth via their interactions with NgR1 and NgR2 expressed on neurons. In vitro, cells expressing NgR1/2 are inhibited from adhering to and spreading on a myelin substrate. Neuronal injury also results in the presence of dendritic cells (DCs) in the central nervous system, where they can come into contact with myelin debris. The exact mechanisms of interaction of immune cells with CNS myelin are, however, poorly understood.MethodsHuman DCs were differentiated from peripheral blood monocytes and mouse DCs were differentiated from wild type and NgR1/NgR2 double knockout bone marrow precursors. NgR1 and NgR2 expression were determined with quantitative real time PCR and immunoblot, and adhesion of cells to myelin was quantified.ResultsWe demonstrate that human immature myeloid DCs express NgR1 and NgR2, which are then down-regulated upon maturation. Human mature DCs also adhere to a much higher extent to a myelin substrate than immature DCs. We observe the same effect when the cells are plated on Nogo-66-His (binding peptide for NgR1), but not on control proteins. Mature DCs taken from Ngr1/2 knockout mice adhere to a much higher extent to myelin compared to wild type mouse DCs. In addition, Ngr1/2 knockout had no effect on in vitro DC differentiation or phenotype.ConclusionsThese results indicate that a lack of NgR1/2 expression promotes the adhesion of DCs to myelin. This interaction could be important in neuroinflammatory disorders such as multiple sclerosis in which peripheral immune cells come into contact with myelin debris.

The expression of B7-H1 and B7-H4 molecules on immature myeloid and lymphoid dendritic cells in cord blood of healthy neonates.

The aim of our study was to estimate both B7-H1 and B7-H4 molecules on immature myeloid and lymphoid dendritic cells in umbilical cord blood of healthy neonates in comparison with peripheral blood of healthy adults. Thirty nine healthy full-term neonates from physiological single pregnancies and 27 healthy adults were included in the study. The expression of B7-H1 and B7-H4 was revealed using the immunofluorescence method. Statistical analysis was performed using a non-parametric test (Mann-Whitney U-Test). The percentages of BDCA-1+ dendritic cells with B7-H1 and B7-H4 expressions were significantly higher in peripheral blood of healthy adults (p<0.00003). It was either observed that the percentage of BDCA-2+ dendritic cells with the expression of B7-H4 molecules was significantly higher in peripheral blood of healthy adults in comparison with umbilical cord blood (p<0.02). Decreased percentages of dendritic cells and co-stimulatory molecules indicate that neonates have immature immune system. Depletion of co-stimulatory B7-H1 and B7-H4 molecules enable appropriate development of immune response.

The expression of B7-H1 and B7-H4 molecules on immature myeloid and lymphoid dendritic cells in cord blood of healthy neonates.

The expression of B7-H1 and B7-H4 molecules on immature myeloid and lymphoid dendritic cells in cord blood of healthy neonates.