Epithelial Dendritic Cells Research Articles

Elevated expression of IL-17RB and ST2 on myeloid dendritic cells is associated with a Th2-skewed eosinophilic inflammation in nasal polyps

BackgroundInterleukin(IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP) underlie the crosstalk between epithelial cells and dendritic cells (DCs) during the development of Th2 responses. This study aimed to measure the expressions of IL-17RB, ST2 and TSLPR, receptor of IL-25, IL-33, and TSLP respectively, on myeloid DCs in nasal polyps (NP) and evaluate their association with local Th2 inflammation and disease severity in patients with NP.MethodsSamples were collected from 30 NP patients and 16 control subjects recruited prospectively. The mRNA expression of cytokines, including TSLP, IL-25 and IL-33, as well as interferon (IFN)-γ, IL-4, IL-5, IL-13 and IL-17A in NP and control tissues was examined by qualitative polymerase chain reaction (qPCR). The expression of IL-17RB, ST2 and TSLPR as well as other surface markers on myeloid DCs (mDCs) was examined by flow cytometry.ResultsIncreased numbers of total and activated mDCs were found in NP patients. mDCs demonstrated significantly higher expression of IL-17RB, ST2 and TSLPR than those in control tissues. The activated mDCs exhibited up-regulations of OX40L and ICOSL, but down-regulation of PDL1 in NP. Moreover, the IL-17RB, ST2 and TSLPR levels on mDCs were positively correlated with IL-25, IL-33 and TSLP mRNA levels, respectively, in NP. Furthermore, IL-17RB and ST2 expressions on mDCs were correlated with the IL-5 mRNA level as well as eosinophil number in NP. Importantly, the IL-17RB expression on mDCs and the OX40L expression on activated mDCs in NP were positively correlated with CT score and total nasal symptom score.ConclusionsIncreased expressions of IL-17RB and ST2 on mDCs are associated with enhanced local Th2 inflammation in NP, suggesting that mDCs might play a role in IL-25- and IL-33-induced type 2 responses and eosinophilic inflammation in NP.

Assessment of Corneal Changes Associated with Topical Antiglaucoma Therapy Using in vivo Confocal Microscopy

Purpose: Ocular surface disease (OSD) is highly prevalent in eyes treated with chronic, topical antiglaucoma (A/G) therapy. The purpose of this study was to utilize in vivo confocal microscopy (IVCM) to evaluate the corneal morphology, including characteristics of corneal epithelial cells, presence of epithelial dendritic cells (DCs), and characteristics of subbasal nerve plexus, of eyes under topical A/G therapy versus normal eyes. Methods: Central corneal images were prospectively captured from 30 eyes of 16 patients under topical A/G therapy (>6 months) and 20 normal control eyes, using IVCM (HRT 3 RCM, Heidelberg, Germany). Demographic data were collected, as well as information on the types and duration of A/G therapy. In addition, OSD index (OSDI) score, tear film breakup time, Schirmer 1 test results, density of epithelial wing cells (WCs) and basal cells (BCs), subbasal nerve features (density, tortuosity, and reflectivity), and presence of DCs were all assessed and recorded by trained Doheny Image Reading Center graders. Results: IVCM findings of 30 glaucomatous eyes and 20 normal control eyes were analyzed. The mean OSDI score was 8.72 in controls and 32.06 in patients under A/G therapy (p = 0.002). Nerve fiber density, nerve fiber reflectivity, and BC density were all decreased in the A/G group (1,789.07 ± 785.70 μm/frame, 2.79 ± 0.83, 6,457.67 ± 692.55 cells/mm², respectively) as compared to controls (2,815.981 ± 563.77 μm/frame, 3.52 ± 0.50, 7,854.13 ± 1,073.69 cells/mm², respectively) (p < 0.05), whereas the decrease in WC density was statistically nonsignificant (p = 0.5). Nerve tortuosity and DC density were both significantly greater in the A/G eyes (3.00 ± 0.57, 71.24 ± 61.74 cells/mm², respectively) compared to controls (2.10 ± 0.42, 34.08 ± 11.70 cells/mm², respectively) (p < 0.05). Tear film breakup time and Schirmer 1 test results were significantly lower in the A/G group as compared to controls (p < 0.001). Conclusions: Using IVCM, our study identified significant microstructural alterations in the corneas of eyes treated with topical A/G therapy. In addition, our study also revealed that glaucoma patients treated with topical A/G therapy report significantly higher OSDI scores compared to controls. Thus, IVCM may be a useful tool in providing structural parameters to correlate with the functional OSDI assessments in the evaluation of ocular surface toxicity associated with topical A/G therapy.

Murine CD8+ Invariant Natural Killer T Cells are Negatively Selected by CD1d Expressed on Thymic Epithelial Cells and Dendritic Cells

ABSTRACTBackground: CD1d-dependent invariant natural killer (iNKT) cells are found as either CD4 single positive (SP) or CD4/CD8 double negative (DN) cells in mice. The size of the CD8+ iNKT population is extremely small. It is known that CD1d expression on developing thymocytes is sufficient for iNKT development and co-receptor choice, which is driven by Th-POK expression. This study aimed to examine the factors involved in the CD4/CD8 co-receptor choice of iNKT cells in addition to Th-POK-driven silencing of CD8 expression. Methods: In this study, we compared iNKT cells of wild-type (WT) mice with those of transgenic mice in which CD1d expression is restricted to developing thymocytes by the proximal Lck (pLCK) promoter. CD8 positive iNKT cell population were analyzed by flow cytometry. Results: We found that there was a substantial population of CD8+ iNKT cells in the thymus and spleen of transgenic mice, and these cells are negatively selected in between Stage 2 and Stage 3 of their developmental program by the CD1d expressed on Thymic epithelial cell (TEC) and Dendritic cells in WT mice. Conclusion: We conclude that TEC expression of CD1d in the murine thymus contributed to co-receptor choice of iNKT cells, in addition to Th-POK-driven silencing of CD8. Therefore, mostly CD4 SP and DN iNKT cells are produced under normal physiological conditions in mice.

Loss of Neurokinin-1 Receptor Alters Ocular Surface Homeostasis and Promotes an Early Development of Herpes Stromal Keratitis.

Substance P neuropeptide and its receptor, neurokinin-1 receptor (NK1R), are reported to present on the ocular surface. In this study, mice lacking functional NK1R exhibited an excessive desquamation of apical corneal epithelial cells in association with an increased epithelial cell proliferation and increased epithelial cell density, but decreased epithelial cell size. The lack of NK1R also resulted in decreased density of corneal nerves, corneal epithelial dendritic cells (DCs), and a reduced volume of basal tears. Interestingly, massive accumulation of CD11c+CD11b+ conventional DCs was noted in the bulbar conjunctiva and near the limbal area of corneas from NK1R-/- mice. After ocular HSV-1 infection, the number of conventional DCs and neutrophils infiltrating the infected corneas was significantly higher in NK1R-/- than C57BL/6J mice. This was associated with an increased viral load in infected corneas of NK1R-/- mice. As a result, the number of IFN-γ-secreting virus-specific CD4 T cells in the draining lymph nodes of NK1R-/- mice was much higher than in infected C57BL/6J mice. An increased number of CD4 T cells and mature neutrophils (CD11b+Ly6ghigh) in the inflamed corneas of NK1R-/- mice was associated with an early development of severe herpes stromal keratitis. Collectively, our results show that the altered corneal biology of uninfected NK1R-/- mice along with an enhanced immunological response after ocular HSV-1 infection causes an early development of herpes stromal keratitis in NK1R-/- mice.

In Vivo Confocal Microscopy in Dry Eye Disease Associated With Chronic Graft-Versus-Host Disease.

To compare densities of corneal epithelial dendritic cells (DCs), corneal subbasal nerves, and conjunctival epithelial immune cells (EICs) between patients with dry eye disease (DED) with and without graft-versus-host disease (GVHD) using in vivo confocal microscopy (IVCM). This study included 54 patients who had moderate to severe DED either associated with (n = 33) or without (n = 21) chronic GVHD. In addition to evaluating clinical parameters of DED, images obtained by laser-scanning IVCM of the central cornea and superior tarsal conjunctiva were analyzed to measure densities of corneal epithelial DCs, corneal subbasal nerves, and conjunctival EICs. Although there were no significant differences between GVHD and non-GVHD groups in symptom scores, the GVHD group had significantly worse corneal fluorescein staining, tear break-up time, and Schirmer's scores than the non-GVHD group. Corneal epithelial DC density, corneal subbasal nerve density, and conjunctival EIC density were 148 ± 135 cells/mm2, 16.3 ± 6.1 mm/mm2, and 670 ± 267 cells/mm2, respectively, in the GVHD group; and 122 ± 99 cells/mm2, 18.3 ± 5.1 mm/mm2, and 572 ± 271 cells/mm2, respectively, in the non-GVHD group. After adjusting for clinical parameters, including the DED severity, none of the IVCM parameters was significantly different between the GVHD versus non-GVHD groups (P = 0.82, P = 0.21, and P = 0.60, respectively). In GVHD-associated DED, cellular changes in the cornea and conjunctiva observed by IVCM were similar to those seen in patients who have non-GVHD dry eye with the same level of disease severity. Therefore, corneal and conjunctival IVCM findings in GVHD-associated DED are possibly reflective of the local disease (DED) severity rather than the underlying systemic disease process.

Expression of cell cycle and apoptosis regulators in thymus and thymic epithelial tumors.

The human thymus supports the production of self-tolerant T cells with competent and regulatory functions. Various cellular components of the thymic microenvironment such as thymic epithelial cells (TEC) and dendritic cells play essential roles in thymic T cell differentiation. The multiple cellular events occurring during thymic T cell and TEC differentiation involve proteins regulating cell cycle and apoptosis. Dysregulation of the cell cycle and apoptosis networks is involved in the pathogenesis of thymic epithelial tumors (TET) which are divided into two broad categories, thymomas and thymic carcinomas. The present review focuses on the usefulness of the analysis of the expression patterns of major cell cycle and apoptosis regulators in order to gain insight in the histophysiology of thymus and the histopathology, the clinical behavior and the biology of TET.

Micro RNA as Biomarkers and Tool for Target-Based Treatment in Patients with Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are common group of digestive inflammatory disorder, which characterized defective regulation of adaptive immunity. There are raised evidences that intercellular cooperation affected epithelial cells, macrophages and dendritic cells play a pivotal role in gut homeostasis. Therefore, dysregulation of cell cooperation may lead to decreased epithelial integrity and worsening of IBD. Recent pre-clinical and clinical investigations have shown that micro RNAs are involved in several pathological processes affected cell-to-cell cooperation, transferring information, tissue repair mediating, angiogenesis and neo-vascualrization. The mini review is discussed the potential role of micro RNAs as biomarkers and tool for target-based treatment in patients with inflammatory bowel diseases

Role of Chlamydophila pneumoniae in the Pathogenesis of Chronic Cerebrospinal Venous Insuffiency in Patients with Multiple Sclerosis

Although the aetiology of Multiple Sclerosis (MS) is unknown, genetic and environmental factors including infectious agents may play a role in the development of this disease. Recent studies have demonstrated chronic cerebrospinal venous insufficiency (CCSVI) as a potential factor in the pathogenesis of clinically defined MS but current evidence does not support a substantial role of CCSVI in the pathogenesis of the classic MS lesions. As the association of Chlamydophila pneumoniae with vascular infections and endothelial dysfunction due to inflammation is well known, C. pneumoniae could be implicated in the development of CCSVI. This hypothesis is based on the ability of this pathogen to infect venous endothelial cells that could contribute to an inflammatory-autoimmune process in venous tissue leading to the venous anomalies (venous stenosis/occlusions) described in CCSVI. In fact, besides the recognized infection by C. pneunoniae of a large variety of cells including alveolar epithelial cells, macrophages, dendritic cells, B and T-cells, neuronal glia and neuronal ependymal cells, this pathogen may also infect vascular endothelial cells in venous tissues. Such an infection/inflammation of venous vascular tissues could contribute to the inflammatory-autoimmune disease causing the venous abnormalities described in the so-called CCSVI.

PL04.3 Protective and Non-Protective Immunity in STIs

Protective and non-protective immunity in STIs.It is certainly remarkable that the causative agents of sexually transmitted infections (STIs) induce long-lasting protective immune responses only occasionally and insufficiently (T. pallidum, human papilloma viruses, herpes simplex virus, S. scabie) or not at all (C. trachomatis, N. gonorrhoeae”, C. albicans, human immunodeficiency virus, T. vaginalis).The reasons for this phenomenon are often microbe-related, but may also be due to peculiarities of the mucosal immune system. Evidence exists, for instance, that density and function of epithelial dendritic cells in the mucosa are different from those in the epidermis and, perhaps as a consequence of this, mucosal sensitization more often results in T cell non-responsiveness or anergy than epicutaneous sensitization.The relatively poor functionality of the adaptive immune response in the defence against the various STI-causing microorganisms can sometimes by compensated by cells and molecules of the innate immune system. Good examples of this are the overexpression of certain anti-microbial peptides in the vaginal epithelium and the imiquimod-induced cytotoxic response of plasmacytoid dendritic cells against HPV-infected targets.At a time where we are challenged with increased anti-microbial resistance to anti-microbial chemotherapy, research efforts are needed to better understand the mechanisms of microbe - host cell interactions and to use this knowledge for the development of better therapeutic strategies.

Alterations of the autoimmune regulator transcription factor and failure of central tolerance: APECED as a model

Self–nonself discrimination plays a key role in inducing a productive immunity and in preventing autoimmune reactions. Central tolerance within the thymus and peripheral tolerance in peripheral lymphoid organs lead to immunologic nonresponsiveness against self-components. The central tolerance represents the mechanism by which T cells binding with high avidity to self-antigens are eliminated through the so-called negative selection. Thymic medullary epithelial cells and medullary dendritic cells play a key role in this process, through the expression of a large number of tissue-specific self-antigens involving the transcription factor autoimmune regulator (AIRE). Mutations of AIRE result in autoimmune polyendocrinopathy candidiasis ectodermal dystrophy, a rare autosomal recessive disease (OMIM 240300), which is the paradigm of a genetically determined failure of central tolerance and autoimmunity. This review focuses on recent advances in the molecular mechanisms of central tolerance, their alterations and clinical implication.

Nanoemulsion nasal adjuvant W805EC induces dendritic cell engulfment of antigen-primed epithelial cells

Nanoemulsions are adjuvants that enhance antigen penetration in the nasal mucosa, increase cellular uptake of antigens by both epithelial dendritic cells, and promote migration of antigen-loaded dendritic cells to regional lymph nodes within a day of vaccine administration. The objective of this study was to determine whether the W805EC nanoemulsion adjuvant enhances immune response not only by direct uptake of antigen by dendritic cells, but also indirectly, by phagocytosis of antigen-primed, apoptotic, epithelial cells. Consistent with this, we show that exposure of both epithelial cells (TC-1s) and dendritic cells (JAWS II or bone marrow derived dendritic cells (BMDCs)) to nanoemulsion exhibited augmented antigen uptake in cell culture. TC-1 cells subsequently underwent G2/M cell cycle arrest and apoptosis, and when co-cultured with JAWS II or BMDCs were rapidly engulfed by the dendritic cells, which responded by up-regulating dendritic cell maturation marker CD86. Altogether these results suggest that the effectiveness of nanoemulsions as adjuvants stems, at least in part, from the engulfment of antigen-loaded epithelial cells, leading to enhanced antigen processing and a strong and balanced mucosal and systemic immune response.

Morphometric analysis of dendritic cells from anal mucosa of HIV-positive patients and the relation to intraepithelial lesions and cancer seen at a tertiary health institution in Brazil

To morphometrically quantify CD1a+ dentritic cells and DC-SIGN+ dendritic cells in HIV-positive patients with anal squamous intraepithelial neoplasia and to evaluate the effects of HIV infection, antiretroviral therapy and HPV infection on epithelial and subepithelial dendritic cells. A prospective study was performed to morphometrically analyze the relative volume of the dendritic cells and the relationship between anal intraepithelial neoplasia and cancer in HIV-positive patients from the Tropical Medicine Foundation of Amazonas, Brazil. All patients were submitted to biopsies of anorectal mucosa to perform a classic histopathological and immunohistochemical analysis, employing antibodies against CD1a and DC-SIGN for the morphometric quantification of dendritic cells. HIV-negative patients displayed a CD1a DC density significantly higher than that of HIV-positives patients (3.75 versus 2.54) (p=0.018), and in patients with severe anal intraepithelial neoplasia had correlated between DC CD1a density with levels of CD4 + cells (p: 0.04) as well as the viral load of HIV-1 (p: 0.035). A not significant rise in the median density of CD1a+ DC was observed in the HIV positive/ HAART positive subgroup compared to the HIV positive/ HAART negative subgroup. The CD1a+ DC were also significantly increased in HIV-negative patients with anorectal condyloma (2.33 to 3.53; p=0.05), with an opposite effect in HIV-positive patients. Our data support an enhancement of the synergistic action caused by HIV-HPV co-infection on the anal epithelium, weakening the DC for its major role in immune surveillance. Notoriously in patients with severe anal intraepithelial neoplasia, the density of CD1a+ epithelial dendritic cells was influenced by the viral load of HIV-1. Our study describes for the first time the density of subepithelial DC-SIGN+ dendritic cells in patients with anal severe anal intraepithelial neoplasia and points to the possibility that a specific therapy for HIV induces the recovery of the density of epithelial DC.

Inflammation and the Nervous System: The Connection in the Cornea in Patients with Infectious Keratitis

To study the density and morphologic characteristics of epithelial dendritic cells, as correlated to subbasal corneal nerve alterations in acute infectious keratitis (IK) by in vivo confocal microscopy (IVCM). IVCM of the central cornea was performed prospectively in 53 eyes with acute bacterial (n = 23), fungal (n = 13), and Acanthamoeba (n = 17) keratitis, and in 20 normal eyes, by using laser in vivo confocal microscopy. Density and morphology of dendritic-shaped cells (DCs) of the central cornea, corneal nerve density, nerve numbers, branching, and tortuosity were assessed and correlated. It should be noted that due to the "in vivo" nature of the study, the exact identity of these DCs cannot be specified, as they could be monocytes or tissue macrophages, but most likely dendritic cells. IVCM revealed the presence of central corneal DCs in all patients and controls. The mean DC density was significantly higher in patients with bacterial (441.1 ± 320.5 cells/mm(2); P < 0.0001), fungal (608.9 ± 812.5 cells/mm(2); P < 0.0001), and Acanthamoeba keratitis (1000.2 ± 1090.3 cells/mm(2); P < 0.0001) compared with controls (49.3 ± 39.6 cells/mm(2)). DCs had an increased size and dendrites in patients with IK. Corneal nerves were significantly reduced in eyes with IK compared with controls across all subgroups, including nerve density (674.2 ± 976.1 vs. 3913.9 ± 507.4 μm/frame), total nerve numbers (2.7 ± 3.9 vs. 20.2 ± 3.3), main trunks (1.5 ± 2.2 vs. 6.9 ± 1.1), and branching (1.2 ± 2.0 vs. 13.5 ± 3.1; P < 0.0001). A strong association between the diminishment of corneal nerves and the increase of DC density was observed (r = -0.44; P < 0.0005). IVCM reveals an increased density and morphologic changes of central epithelial DCs in infectious keratitis. There is a strong and significant correlation between the increase in DC numbers and the decreased subbasal corneal nerves, suggesting a potential interaction between the immune and nervous system in the cornea.

Corneal Involvement in Crohn's Disease: An In Vivo Confocal Microscopy Study

To evaluate the corneal changes of patients with Crohn's disease (CD) using confocal microscopy and to investigate the association among confocal parameters and CD activity and CD treatment. Thirty consecutive patients (age: 42 ± 12 years; 19 women and 11 men) affected by CD and 30 control eyes (age matched and gender matched) underwent an ophthalmic examination and, in 1 eye chosen at random, confocal microscopy of the central cornea using the cornea module of Heidelberg Retina Tomograph. The following confocal parameters were evaluated: density of basal epithelial cells, epithelial dendritic cells, anterior and posterior stromal keratocytes, and endothelial cells; the subbasal plexus was assessed for number and tortuosity of the nerve fibers. Routine ophthalmic evaluation was normal in the whole population. At confocal microscopy, 40% of patients with CD had hyperreflective dots in the basal epithelium, which were absent in the control group. Activation of keratocytes was found in 86.6% of patients with CD and was absent in the control group. Compared with controls, patients with CD had lower density of dendritic cells (12.2 ± 26.3 vs. 50.3 ± 37.6 cells per square millimeter; P = 0.001). The other confocal parameters were similar in the 2 groups. No correlation between CD activity index and confocal changes was found. Confocal microscopy can detect subtle corneal changes in patients with CD, which may be signs of subclinical inflammation.

Targeting the innate immune system in pediatric inflammatory bowel disease

The pathogenesis of inflammatory bowel disease (IBD) is complex and involves both innate and adaptive immune responses. This article addresses, in a selective and speculative fashion, the topic of how the various components of the intestinal innate immune system can be manipulated for the purpose of developing new therapeutic approaches. These various components include: agents that stimulate mucosal innate immune responses, such as food components and the gut microbiota; cells that directly respond to these stimuli, including epithelial cells, macrophages and dendritic cells; and molecules that mediate innate immune responses, such as Toll-like receptors and protein kinases. Downregulation of excessive innate immune responses makes therapeutic sense in both pediatric and adult IBD. However, because IBD is complex and characteristically chronic, major alterations of adaptive immunity are also involved in the mediation of inflammation. Thus, novel and truly effective approaches to treat IBD will undoubtedly require intervening in the innate as well as the adaptive branches of the mucosal immunity.

Transcriptome atlas of serine family amino acid metabolism-related genes in eight rat regenerating liver cell types

To explore the transcription profiles of serine family amino acid metabolism-related genes in eight liver cell types during rat liver regeneration (LR), eight types of rat regenerating liver cells were isolated using the combination of percoll density gradient centrifugation and immunomagnetic bead methods. Then, the expression profiles of the genes associated with metabolism of serine family amino acid in rat liver regeneration were detected by Rat Genome 230 2.0 Array. The expression patterns of these genes were analyzed through the software of Cluster and Treeview. The activities of serine family amino acid metabolism were analyzed by the methods of bioinformatics and systems biology. The results showed that 27 genes were significantly expressed. Among them, the numbers of genes showing significant expression changes in hepatocytes, biliary epithelial cells, oval cells, hepatic stellate cells, sinusoidal endothelial cells, Kupffer cells, pit cells and dendritic cells were 13, 16, 11, 14, 13, 11, 12, and 14, respectively. The numbers of up-, down-, and up-/down-regulated genes in corresponding cells were 7, 6, and 0; 2, 10, and 4; 2, 8, and 1; 8, 3, and 3; 6, 5, and 2; 4, 6, and 1; 2, 10, and 0; and 6, 6, and 2. Overall, the genes in the eight types of cells were mostly down-regulated during liver regeneration, but most LR-related genes in hepatic stellate cells and sinusoidal endothelial cells were up-regulated in priming phase. It is suggested that biosynthesis of serine family amino acid was enhanced in hepatocytes, hepatic stellate cells, sinusoidal endothelial cells and Kupffer cells in the priming phase. The catabolism of them was enhanced in hepatocytes, biliary epithelial cells, pit cells and dendritic cells in progressive phase.

Virosomes can enter cells by non-phagocytic mechanisms

Phagocytosis of fine particles (1 μm) by macrophages is a ligand-receptor–mediated, actin-based process, whereas the entering of smaller particles (≤ 0.2 μm) in macrophages occurs also by other mechanisms. Virosomes with a diameter of 0.12–0.18 μm are widely used as carrier systems for drugs, vectors, and plasmids in cancer therapy or for vaccines. We investigated their interactions with airway cells, in particular penetration into monocyte-derived macrophages. The microscopic analysis of phagocytic cells incubated with virosomes and polystyrene particles showed that virosomes and particles penetrated cells even in the presence of cytochalasin D, a drug inhibiting actin-based phagocytosis. The charge of the virosomes and particles did not influence their penetration. Also, different inhibitors of endocytotic pathways did not prevent the particles and virosomes from penetrating into the cells. Additionally, to study the ability of virosomes to overcome the epithelial airway barrier, a triple cell co-culture model composed of epithelial cells, monocyte-derived macrophages and dendritic cells of the respiratory tract was used. We found virosomes and polystyrene particles in both populations of antigen-presenting cells, monocyte-derived macrophages, and dendritic cells, in the latter even if they were not directly exposed. In conclusion, virosomes are readily taken up by monocyte-derived macrophages, both by conventional phagocytosis and by actin-independent mechanisms. Further, they can penetrate the airway barrier and reach resident dendritic cells. Therefore, virosomes are promising vaccine candidates.

Normal human bulbar conjunctiva on confocal microscopy in vivo

To analyze the morphology of human bulbar conjunctiva by in vivo laser scanning confocal microscopy. This research was a cross-sectional study. From February to July 2008, 50 eyes of 50 healthy subjects were enrolled in this study. They had no history of ocular trauma, infection or contact lens wear and had no found after routine slit-lamp examinations. In vivo laser scanning confocal microscopic examinations were performed on the superior, inferior, nasal and temporal bulbar conjunctiva and the images were recorded. The morphology of bulbar conjunctiva was analyzed and the density of epithelial cells, dendritic cells and goblet cells were calculated. One-way analysis of variance (ANOVA) was used to compare the means of epithelial cell densities in different layers and goblet cell densities in different positions. Subsequently the datum between two groups were analyzed by least significant difference (LSD). Superficial epithelial cells of bulbar conjunctiva were characterized as large loose-arranged cells with a hyporeflective nucleus. The mean density is (1643 +/- 206) cells/mm(2). Intermediate epithelial cells were captured with features of oval small tight-arranged cells with a punctiform hyperreflective nucleus. The mean density is (4693 +/- 228) cells/mm(2). Basal epithelial cells appeared to be polygonal and regular-arranged within hyperreflective cell borders. The mean density is (4420 +/- 230) cells/mm(2). There was a significant difference among three kinds of conjunctival epithelium (F = 1160.312, P = 0.000). The presumed goblet cell was defined as a large hyperreflective oval-shaped cell with relatively homogeneous brightness, crowded in groups or mainly dispersed. The mean density is (432 +/- 72) cells/mm(2). The dendritic cell appeared to be hyperreflective corpuscular particles with dendritic processes scattered among conjunctival epithelial cells. The mean density is (22 +/- 25) cells/mm(2). The basement membrane, a prominent hyperreflective band, separated epithelial cells from subepithelial structure. Bulbar conjunctival substantia propria, beneath the basement membrane, was mainly composed of highly vascularized, loose connective tissues which were irregularly arranged fibers or a network of fibers, punctiform hyperreflective immune cells and sharp flows of blood vessels. In vivo laser scanning confocal microscopy is a useful tool in the analysis of the bulbar conjunctival morphology, which provided a fast and noninvasive method for the diagnosis of ocular surface diseases.

SY-19 From epithelial innate to adaptive immune response: cross talk between epithelial cells and dendritic cells

SY-19 From epithelial innate to adaptive immune response: cross talk between epithelial cells and dendritic cells

Histochemical and molecular overview of the thymus as site for T-cells development

The thymus represents the primary site for T cell lymphopoiesis, providing a coordinated set for critical factors to induce and support lineage commitment, differentiation and survival of thymus-seeding cells. One irrefutable fact is that the presence of non-lymphoid cells through the thymic parenchyma serves to provide coordinated migration and differentiation of T lymphocytes. Moreover, the link between foetal development and normal anatomy has been stressed in this review. Regarding thymic embryology, its epithelium is derived from the embryonic endodermal layer, with possible contributions from the ectoderm. A series of differentiating steps is essential, each of which must be completed in order to provide the optimum environment for thymic development and function. The second part of this article is focused on thymic T-cell development and differentiation, which is a stepwise process, mediated by a variety of stromal cells in different regions of the organ. It depends strongly on the thymic microenvironment, a cellular network formed by epithelial cells, macrophages, dendritic cells and fibroblasts, that provide the combination of cellular interactions, cytokines and chemokines to induce thymocyte precursors for the generation of functional T cells. The mediators of this process are not well defined but it has been demonstrated that some interactions are under neuroendocrine control. Moreover, some studies pointed out that reciprocal signals from developing T cells also are essential for establishment and maintenance of the thymic microenvironment. Finally, we have also highlighted the heterogeneity of the lymphoid, non-lymphoid components and the multi-phasic steps of thymic differentiation. In conclusion, this review contributes to an understanding of the complex mechanisms in which the foetal and postnatal thymus is involved. This could be a prerequisite for developing new therapies specifically aimed to overcome immunological defects, linked or not-linked to aging.