Biomedical subjects

V Calder

Publications and source records attributed to V Calder.

9 recordsLinked to original sources

PubMed2005

Intracellular T lymphocyte cytokine profiles in the aqueous humour of patients with uveitis and correlation with clinical phenotype.

This study aimed to investigate whether T cells in aqueous humour are different in different types of uveitis and correlate with clinical phenotype. Patients with clinically different types of uveitis, but all displaying active anterior uveitis, were phenotyped and samples of aqueous humour (AH) and peripheral blood (PB) collected. Cells from AH and PB were separated by centrifugation and by density gradient centrifugation (to obtain mononuclear cells PBMC), respectively. Cells were activated with PMA and ionomycin in the presence of Brefeldin A, stained for surface markers and intracellular cytokines, and analysed by flow cytometry. The cytokine profile was correlated with the clinical phenotype. Increased percentages of interleukin (IL)-10+-, but not interferon (IFN)-gamma+ T lymphocytes were found in AH compared with PB in patients with acute anterior uveitis (AAU), FHC or chronic panuveitis (PU). There was a trend towards elevated levels of IL-10+ T cells in AH from patients with FHC compared with AH from acute uveitis and panuveitis patients. Increased levels of IL-10+ T cells in AH compared with PB were also found in samples from patients with isolated uveitis, but not those with associated systemic disease. Levels of cytokine-positive T cells were not associated with the use of topical steroids or to the severity of the anterior uveitis. While type I cytokine-producing T lymphocytes are present in AH during AU, the presence of increased proportions of IL-10+ T lymphocytes in AH from patients with uveitis may be indicative of an anti-inflammatory mechanism that may influence the type and course of ocular inflammation in these patients.

Acute Disease↗

PubMed2000

T cells and fibroblasts in affected extraocular muscles in early and late thyroid associated ophthalmopathy.

AIM: To determine whether there are differences in the lymphocytic cell infiltrate present in affected extraocular muscles (EOM) during early and late stages of thyroid associated ophthalmopathy (TAO). METHODS: 17 biopsies of affected EOMs were collected from two groups of TAO patients (n=14): the first of five patients with early, active TAO, and the second of nine patients with late, inactive TAO. The control group was of EOM biopsies taken from 14 non-TAO patients undergoing squint surgery. Immunohistochemical analysis was undertaken using the relevant monoclonal antibodies and an avidin-biotin system and the three groups compared. RESULTS: Both CD4+ and CD8+ T cells were found in the cellular infiltrate in early, active TAO specimens which were much less evident either in late, inactive stage disease or in control tissue. There was also a significant increase in both CD45RO+ and CD45RB+ cells and macrophages in early TAO compared with the others. Increased expression of HLA-DR antigen by interstitial cells including fibroblasts was detected in both early and late disease but the EOM fibres remained morphologically intact and did not express MHC class II antigens at any time. CONCLUSION: These results demonstrate that T cells are only significantly present in early disease but increased HLA-DR antigen expression on fibroblasts is observed at all stages. This suggests that T cells are much more involved in the early than the later stages of the disease process and that early activation of fibroblasts occurs. Early intervention with immunosuppressive therapy to downregulate cytokine production by T cells may significantly influence the sequelae caused by EOM fibrosis.

Adult↗

PubMed1999

Lymphocyte migration through brain endothelial cell monolayers involves signaling through endothelial ICAM-1 via a rho-dependent pathway.

Lymphocyte extravasation into the brain is mediated largely by the Ig superfamily molecule ICAM-1. Several lines of evidence indicate that at the tight vascular barriers of the central nervous system (CNS), endothelial cell (EC) ICAM-1 not only acts as a docking molecule for circulating lymphocytes, but is also involved in transducing signals to the EC. In this paper, we examine the signaling pathways in brain EC following Ab ligation of endothelial ICAM-1, which mimics adhesion of lymphocytes to CNS endothelia. ICAM-1 cross-linking results in a reorganization of the endothelial actin cytoskeleton to form stress fibers and activation of the small guanosine triphosphate (GTP)-binding protein Rho. ICAM-1-stimulated tyrosine phosphorylation of the actin-associated molecule cortactin and ICAM-1-mediated, Ag/IL-2-stimulated T lymphocyte migration through EC monolayers were inhibited following pretreatment of EC with cytochalasin D. Pretreatment of EC with C3 transferase, a specific inhibitor of Rho proteins, significantly inhibited the transmonolayer migration of T lymphocytes, endothelial Rho-GTP loading, and endothelial actin reorganization, without affecting either lymphocyte adhesion to EC or cortactin phosphorylation. These data show that brain vascular EC are actively involved in facilitating T lymphocyte migration through the tight blood-brain barrier of the CNS and that this process involves ICAM-1-stimulated rearrangement of the endothelial actin cytoskeleton and functional EC Rho proteins.

ADP Ribose Transferases↗

PubMed1999

Characterization of soluble factors from cultures of premalignant cervical epithelium.

PURPOSE: Immune responses within the cervical microenvironment are likely to play an important role in the natural history of premalignant lesions but the pattern of this response and how it is regulated has not been documented in detail. METHODS: Explants of premalignant cervical epithelium were cultured in vitro for 24 hours. The culture supernatants were assayed for the presence of IL-1alpha, IL-10, IL-12 and TNF-alpha by ELISA. Aliquots of each supernatant were also added to a CD3-dependent T cell proliferation assay. RESULTS: The pattern of cytokines found in different samples was heterogeneous and no significant correlation was observed between the various cytokines examined. The functional effects observed were also diverse, with some supernatants showing strong inhibitory T cell activity, while others were stimulatory. CONCLUSION: Our results document the heterogeneity of the local cytokine microenvironment of premalignant cervical lesions, which may play a role in regulating the immune response associated with such lesions and hence influence clinical outcome.

CD3 Complex↗

PubMed1998

Eosinophil surface antigen expression and cytokine production vary in different ocular allergic diseases.

BACKGROUND: The pathophysiology of chronic ocular allergic disease is not well understood. An eosinophil infiltrate is characteristic of such disease and eosinophil activity can be related to disease severity and to keratopathy, the most serious complication. Recently, eosinophils have been shown capable of cytokine production, particularly in allergic disease, although the disease-specific cytokine spectrum of tissue eosinophils is unknown. OBJECTIVES: We sought to determine eosinophil numbers (absolute numbers and percentage of total leukocytes), cell surface antigen expression, and cytokine production in conjunctiva in chronic allergic eye disease and their relationship to corneal involvement. METHODS: Ultrathin sections of conjunctiva were examined by tissue staining and by 1- and 2-color immunohistochemistry. RESULTS: Eosinophil numbers were greater in giant papillary conjunctivitis (GPC) and vernal keratoconjunctivitis (VKC) and not related to corneal involvement. The eosinophil expression of the cell surface antigens intercellular adhesion molecule-1, CD4, IL-2R, and HLA-DR was greater in atopic keratoconjunctivitis (AKC) and VKC, the disorders with corneal disease, than in GPC, in which the cornea is not involved. For most cytokines, localization to eosinophils was greater for VKC and AKC than for GPC. RANTES, TGF-beta, and TNF-alpha localized to eosinophils in all disorders. Variations in the pattern of eosinophil-cytokine localization were found. In VKC IL-3, IL-5, IL-6, and GM-CSF were prominent; in GPC IL-5 was prominent; and in AKC IL-4, IL-8, and GM-CSF were prominent. CONCLUSIONS: Chronic ocular allergic disorders affecting the cornea are distinguished from disorders that do not do so by greater expression of eosinophil surface antigens (which may imply greater cell activation) and differences in cytokine localization to eosinophils. These differences may be secondary to the variations in T-cell subsets or a primary phenomenon. Changes in eosinophil function, rather than cell numbers, may be important in clinical variations, such as keratopathy, and may allow future therapeutic exploitation.

Adult↗

PubMed1998

Characterization of T cells and cytokines in the aqueous humour (AH) in patients with Fuchs' heterochromic cyclitis (FHC) and idiopathic anterior uveitis (IAU).

FHC and IAU are two forms of anterior uveitis which are localized to the eyes with no evidence of systemic involvement. However, FHC has distinct clinical features and differs from IAU in that the inflammation is low grade, steroid non-responsive, and has a less aggressive clinical course. To try to dissect the mechanism for this difference the phenotypes of the cells in the AH and blood (PB) and the cytokines present in the AH in patients with FHC and IAU were compared. Three-colour flow cytometry was performed on the cells isolated from the AH and PB. Percentage of cells bearing the following markers were determined: CD3, CD4, CD8, CD4/CD25, CD8/CD25, CD19 and CD14. The cytokines IL-4, IL-10, IL-12 and interferon-gamma (IFN-gamma) were assayed by ELISA. In both groups T cell numbers were higher in the AH than PB, although the distribution of T cell subsets in PB was similar. In the AH, CD8+ T cell numbers were higher in FHC than in IAU (P = 0.003), whilst CD4+ numbers were higher in IAU than FHC (P = 0.01). AH cytokine profiles were different in the two groups: IFN-gamma levels were higher and IL-12 levels lower in the FHC group than IAU (P = 0.02), whilst IL-10 levels tended to be higher in the FHC group (P = 0.5). We suggest that different local mechanisms governing the balance of T cell/cytokine-mediated inflammation in the anterior segment may underlie clinical differences such as chronicity and response to steroids in these disorders.

Adolescent↗

PubMed1997

Adhesion molecule expression in vivo on extraocular muscles (EOM) in thyroid-associated ophthalmopathy (TAO).

TAO is an autoimmune condition characterized by mononuclear cell infiltration of the extraocular muscles (EOM) and/or the orbital fat/connective tissue with associated deposition of glycosaminoglycans (GAG) in the interstitial spaces. In this study, the presence and distribution of the vascular adhesion molecules intercellular adhesion molecule-1 (ICAM-1), endothelial-leucocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1) and the leucocyte integrins CD11a/CD18, CD11b/CD18, CD11c/CD18 were investigated. Nineteen EOM biopsies were collected from 17 patients with early (n = 6) and late (n = 13) TAO as well as from 12 non-TAO control patients. Consecutive cryostat sections of these biopsies were immunostained with MoAbs to the above-mentioned molecules and haematoxylin and eosin. Primary antibody binding was visualized using an avidin-biotin system. In early untreated TAO specimens, the interstitial and perimysial connective tissue surrounding EOM fibres and numerous mononuclear cells stained strongly for ICAM-1. In contrast, the vascular endothelial cells (ulex lectin-positive) stained strongly for ELAM-1 (E-selectin), VCAM-1 as well as ICAM-1. In late disease, the same distribution of immunoreactivity for ICAM-1, ELAM-1 and VCAM-1 was observed, but with significantly lower staining. The leucocyte integrins (CD11a, CD11b, CD11c) were again expressed at significantly higher levels in early TAO specimens compared with late TAO specimens and were minimal or absent in the EOM biopsies harvested from control patients. In conclusion, increased expression of adhesion molecules studied correlated with early active disease and was reduced in later stages.

Adult↗

PubMed1997

Analysis of extraocular muscle-infiltrating T cells in thyroid-associated ophthalmopathy (TAO).

TAO is characterized by an autoimmune process affecting the orbital contents. T cells have been suggested to have a major role in pathogenesis, but so far only limited data are available to clarify the extraocular muscle (EOM)-infiltrating T cell phenotype, antigenic reactivity and cytokine profile in TAO patients. In the present study, biopsies of affected EOM were taken and the infiltrating T cells isolated and expanded in vitro with mitogen. Their phenotype was determined by flow cytometric (FACS) analysis and compared with peripheral blood-derived T cell lines, treated in the same way from the same patient. Cytokines present in the supernatant after mitogen stimulation of the T cell lines were assayed by ELISA. In addition, cytokine mRNA present at the time of biopsy was determined by rapid RNA extraction from EOM and reverse transcription-amplification with specific cytokine oligonucleotide probes (IL-1alpha, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, IL- 15, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha)). In the T cell lines from two patients, proliferation assays were carried out with antigens derived from thyroid gland, EOM and a thyrotropin (TSH) receptor preparation. Most T cell lines were CD4+, CD45RO+, and TCR alpha/beta+, both from the EOM and the peripheral blood. A wide variety of cytokines was detected by analysis of supernatants or mRNA, but the profiles were not identical comparing the two approaches. However, IL-4 was detected by both. Dose-dependent proliferation was observed in response to thyroid extract in a biopsy-derived T cell line. In conclusion, EOM-infiltrating T cells from patients with TAO, expanded in vitro, were chiefly CD4+ and produced a mixture of cytokines, including IL-4. The proliferation data suggest that there are thyroid-reactive T cells in EOM.

Adult↗

PubMed1989

MS: a localized immune disease of the central nervous system.

The precise role of T cells in multiple sclerosis (MS) remains to be defined. No MS-specific antigen has been found. The autoimmune hypothesis for MS rests on immune changes seen in the spinal fluid and brain and on the demonstration, in an experimental animal model, that T cells raised to myelin basic protein transfer demyelination. In this review, Virginia Calder and colleagues focus on recent studies suggesting that in MS, the initial T-cell response occurs within the central nervous system and that the blood poorly reflects this immune activity. This contrasts with the animal model, experimental allergic encephalomyelitis, where the initial immune response is peripheral.

Central Nervous System↗