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Characterization of dendritic cell phenotype in allergic conjunctiva: increased expression of Fc epsilon RI, the high-affinity receptor for immunoglobulin E
No full textAbstract
PURPOSE:
Dendritic cells (DCs) express the high-affinity receptor for IgE (Fc(epsilon)RI) on their surface, which may enhance their ability to capture and internalize antigens for presentation to T-lymphocytes. The aim of this study was to determine if expression of Fc(epsilon)RI(+) DCs is increased in the conjunctivae of vernal keratoconjunctivitis (VKC) patients compared with those of normal controls.
METHODS:
Conjunctival biopsies were obtained from non-atopic and VKC patients. Double immunohistochemical staining was carried out using antibodies against Fc(epsilon)RI and the CD1a antigen, a DC marker. The double-positive cells were counted in five representative fields of view for each conjunctival sample.
RESULTS:
Fc(epsilon)RI(+) CD1a(+) cells were present in significantly higher numbers in VKC conjunctivae compared with normal controls (mean cell count of 21.3 in VKC vs5.0 in controls, P<0.005). In normal patients the Fc(epsilon)RI-expressing DCs tended to be confined to the epithelial layer or the superficial substantia propria, but in the VKC samples these Fc(epsilon)RI(+) cells were mainly concentrated in the deeper substantia propria.
CONCLUSIONS:
Fc(epsilon)RI(+) DC numbers are elevated in the conjunctivae of VKC patients, a finding consistent with the results of other studies focusing on atopic conditions. Elevated expression of Fc(epsilon)RI on DCs would facilitate antigen presentation and enhance T-cell priming, thereby contributing to ocular symptoms
Characterisation of the phenotype and function of monocyte-derived dendritic cells in allergic conjunctiva
No full textAbstract
BACKGROUND:
Dendritic cells (DCs) are the most potent antigen-presenting cells involved in initiating the immune response, presenting antigens to T cells and leading to T cell proliferation. In an immature state, DCs lack accessory signals required for T cell stimulation but are highly specialised to capture antigens. Full DC maturation changes the cell surface phenotype and facilitates stimulation of T cell proliferative responses. To examine the degree of DC maturity associated with vernal keratoconjunctivitis (VKC), the authors examined the phenotype and antigen-presentation capability of blood derived DCs from VKC patients and from normal controls.
METHODS:
Flow cytometry was used to identify the cell surface expression of markers of DC maturity (CD83, CD86, major histocompatibility complex class II) and mixed leucocyte reactions to assess DC induction of T cell proliferation.
RESULTS:
DCs derived from VKC patients were of a more mature phenotype than those from normal controls. However, these VKC DCs had reduced capability for induction of T cell proliferation compared with DCs from controls.
CONCLUSION:
The increased maturity of DCs in VKC patients correlates with the heightened immune responsiveness associated with this disorder. A number of mechanisms may underlie the impaired ability of DCs in atopy to stimulate T cell proliferation. This impairment of DC induction of T cell activation is likely to be one factor which contributes to the modified inflammatory response seen in VKC patients and the recognised susceptibility of these patients to viral infection
Gene therapy approaches to disease of the cornea and anterior chamber
Get PDFThe field of ocular gene therapy has become one of the most developed areas within the wider gene therapy field, however most work to date has focused upon the retina with the cornea, by comparison, having seen relatively little application of gene therapy. This thesis describes a program of work to further develop viral gene therapy approaches to the three cellular layers of the cornea, with particular emphasis upon the application of novel vector technologies and overcoming the various challenges presented by each layer. Gene therapy of the corneal endothelium has to date largely aimed to increase or maintain endothelial cell density to improve the quality of donor corneas for engraftment. Such a strategy however carries an inherent risk of oncogenesis and this study has therefore aimed to improve the safety profile of endothelial gene delivery methods. The transduction profile of various AAV serotypes within the corneal stroma was also investigated, and the most promising results applied in an augmentation gene therapy approach to prevent corneal neovascularisation. The selected methodology is shown to mediate high level transgene expression and, when delivering the antiangiogenic factor sFlt1, was highly effective in preventing haem (but not lymph) angiogenesis in a murine model of induced corneal neovascularisation. If long term gene delivery to the corneal epithelium is to be achieved it must be targeted to the limbal epithelial stem cells (LESCs) responsible for the continuous regeneration of the layer. This study has convincingly demonstrated gene delivery to these cells in vivo for the first time, with the methodology developed leading to a lasting transgene expression throughout the LESC daughter cell lineages that comprise the epithelium. In addition to potential application in the treatment of congenital epithelial dystrophies this technique may also provide new insights into LESC biology and the cellular dynamics of epithelial renewal
Regeneration of ocular tissues using gene transfer
Get PDFGene therapy of the eye has made huge advances in recent years, which led to first clinical trials. While these were aimed at replacing a defective gene in inherited disease, research is now expanding to using augmentation gene therapy where a gene is used to modulate the course of disease. We investigated the possibilities of gene transfer of cell cycle modulating genes to induce proliferation in two amitotic tissues essential for vision, the corneal endothelium and retinal pigment epithelium. Corneal endothelial cells (CEC) maintain the water content of the cornea and thereby its clarity. Low CEC density in corneal diseases causes blindness and requires corneal transplantation. Transfer of E2F2, a transcription factor regulating G1 to S phase progression, increases CEC density in human ex vivo cultivated corneas, but only when transferred by adenoviral vector, not lentiviral vector. Instead, lentiviral overexpression of ZONAB, a transcription factor normally inactivated by tight junction protein ZO-1, increased CEC density. Lentiviral downregulation of ZO-1, mimicking loss of cell-cell contacts and loss of contact inhibition, led to CEC proliferation. However, CEC density increase was only achieved in young corneas up to ~60 years-of-age, indicating loss of proliferative capacity with age. RPE loss, as seen in age related macular degeneration (AMD), causes photoreceptor loss and blindness. RPE proliferation could be induced using non-integrating lentiviral vectors delivering E2F2. We showed this in vitro and in vivo after subretinal injection of vector in normal RPE of wildtype mice. To a certain extent, the proliferative effect could also be seen in a transgenic mouse model with degenerated RPE. This concept of in situ regeneration by induction of proliferation could lead to new strategies for CEC loss, especially in donor corneas stored in eye banks. For the RPE, it could be used for treatment of early stages of AMD
Longitudinal Changes to Tight Junction Expression and Endothelial Cell Integrity in a Mouse Model of Sterile Corneal Inflammation
Get PDFPURPOSE: We previously reported that applying toll-like receptor (TLR) ligands to an injured cornea induces corneal edema at 24 hours, which subsides by 1 week. We tested the hypotheses that endothelial expression of the tight-junction protein, zonula occludens-1 (ZO-1), would be altered during experimental sterile corneal inflammation and that endothelial cell density (ECD) would remain unaffected.
METHODS: Anesthetized C57BL/6J mice received central 1-mm corneal abrasions followed by topical application of saline or cytosine-phosphate-guanosine oligodeoxynucleotide (CpG-ODN, TLR-9 agonist). At 24 hours, 1 week and 4 weeks post treatment, spectral-domain optical coherence tomography images were captured. Eyes were enucleated and processed for zonula occludens-1 (ZO-1) immunofluorescent staining. Corneal flatmounts were analyzed for endothelial ZO-1 expression, cell density, polymegethism, and polymorphism. Corneal stromal inflammatory cell infiltration was evaluated at 4 weeks by immunostaining for CD45.
RESULTS: Central corneal thickness (CCT) was increased in CpG-ODN treated eyes at 24 hours, had normalized by 1 week, but was again thickened by 4 weeks. In eyes with CpG-ODN, endothelial cell ZO-1 expression was reduced at 24 hours but returned to normal levels by 1 week. Endothelial cell density was not altered at 24 hours or 1 week. By 4 weeks, only CpG-ODN eyes showed relatively reduced ECD, as well as large numbers of CD45+ cells in the stroma. Changes to ECD correlated with CCT (r = −0.53, P < 0.01). Compared with naïve controls, more saline- and CpG-ODN–treated eyes exhibited polymegethism.
CONCLUSIONS: This study provides novel insights into the interplay between endothelial cell integrity, corneal edema, and chronic stromal leukocyte activation during sterile corneal inflammation in mice
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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