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Biomedical subjects

F Fortune

Publications and source records attributed to F Fortune.

At least 19 recordsLinked to original sources
PubMed2006

Diversity of gammadelta T cells in patients with Behcet's disease is indicative of polyclonal activation.

OBJECTIVE: Behcet's disease (BD) is a multisystemic disease, with vasculitic lesions in the oral and genital mucosa, eyes, joints, skin and brain. We have previously found that gammadelta T cells are increased in peripheral blood of BD patients. The aim of this study was to investigate the extent of gammadelta T cells in oral biopsies from BD patients with special emphasis on the restriction of Vgamma and Vdelta usage. PATIENTS AND METHODS: Expression of Vgamma and Vdelta chains on peripheral blood gammadelta T cells from 31 BD patients and 19 healthy controls was analysed by flow cytometry and the expression of Vgamma and Vdelta chains in nine ulcerated and eight non-ulcerated oral mucosa from BD patients and non-ulcerated oral mucosa from three healthy controls was analysed by immunohistochemistry. RESULTS: Vgamma9 and Vdelta2 were the predominant chains expressed in peripheral blood of BD patients, although other Vgamma and Vdelta chains were also expressed. The presence of gammadelta T cells was only observed in the ulcerated oral mucosa but not in the non-ulcerated mucosa from the BD patients, and not in the non-ulcerated mucosa from the healthy controls. These gammadelta T cells showed no preferential expression of any of the Vgamma or Vdelta chains. CONCLUSION: These data suggest a polyclonal rather than oligoclonal activation of the gammadelta T cells. This may indicate that during repeated inflammation of the oral mucosa, the gammadelta T cells are responding to a wide variety of antigenic stimuli with consequent expansion of gammadelta T cells expressing various Vgamma and Vdelta chains and that different antigenic stimuli or responses may be responsible for the clinical heterogeneity of the disease.

Antigenic Variation↗
PubMed2004

Analysis of the CC chemokine receptor 5 (CCR5) Delta32 polymorphism in Behçet's disease.

Chemokines are important determinants of the early inflammatory response. The CC chemokine receptor 5 (CCR5) Delta32 variant results in a non-functional form of the chemokine receptor, and has been implicated in a variety of immune-mediated diseases. To investigate its role in the pathogenesis of Behçet's disease, we studied 350 patients and 519 healthy controls from three ethnic groups. While significant inter-ethnic variation in allele frequency was observed, no association was identified with disease, even when data were stratified by the known susceptibility gene HLA-B*51.

Alleles↗
PubMed2004

Chemokine gene polymorphisms associate with gender in patients with uveitis.

Uveitis is an inflammatory condition of ocular tissue characterized by leukocyte infiltration, tissue damage, and decreased visual acuity. Chemokines have been implicated in the pathogenesis of uveitis. Polymorphisms in the genes encoding chemokines have been described as affecting chemokine production or function. We analyzed the frequency of single-nucleotide polymorphisms (SNPs) in genes encoding CCL2 (-2518 and -2076) and CCL5 (-403 and -28) in patients with Behçet's disease (BD), a systemic form of uveitis, and patients with retinal vasculitis (RV), an organ-specific form of disease. We report that there was no association between any SNP and disease. However, when segregated on the basis of gender the CCR5 -403 AA genotype was only found in male patients with BD. Similarly, CCL2 genotypes 1/2 were predominant in males, while genotype 4 was significantly associated with disease in female patients with BD. Differences in disease symptoms and severity between males and females have been described in BD and gender-specific genetic differences in chemokine gene function may be involved.

Behcet Syndrome↗
PubMed2003

Teaching clinical skills in developing countries: are clinical skills centres the answer?

CONTEXT: There is growing international interest in teaching clinical skills in a variety of contexts, one of which is Clinical Skills Centres. The drivers for change making Skills Centres an important adjunct to ward and ambulatory teaching come both from within and outside medical education. Educationally, self-directed learning is becoming the accepted norm, encouraging students to seek and maximize learning opportunities. There are global changes in health care practice, increased consumerism and increasing student numbers. In some countries, professional recommendations influence what is taught. Increasingly, core skills curricula and outcome objectives are being defined. This explicit definition encourages assessment of the core skills. In turn, all students require equal opportunities to learn how to practise the skills safely and competently. The moves towards interprofessional education make joint learning in a"neutral" setting, like a Clinical Skills Centre, appear particularly attractive. OBJECTIVE: To discuss the potential role of Clinical Skills Centres in skills training in developing countries and to consider alternative options. DISCUSSION: Many developing countries seek to establish Clinical Skills Centres to ensure effective and reliable skills teaching. However, the model may not be appropriate,because fully equipped Clinical Skills Centres are expensive to set up, staff; and run. They are not the only way to achieve high quality clinical teaching. Suggested options are based on the philosophy and teaching methods successfully developed in Clinical Skills Centres that may fulfil the local needs to achieve low cost and high quality clinical teaching which is reflective of the local health needs and cultural expectations.

Clinical Competence↗
PubMed2001

Expression of adhesion and activation molecules in human buccal epithelial cell lines and normal human buccal epithelium in situ.

An in vitro culture system may be used to analyse interactions between T cells and epithelium. We have analysed two human buccal squamous epithelial cell lines: SqCC/Y1, derived from a buccal carcinoma, and SVpgC2a, an SV-transformed healthy buccal squamous epithelium. Under serum-free culture conditions, the cell lines resemble normal buccal squamous epithelium in situ in their expression of MHC class I, CD29 (beta1 integrin), CD40, CD44, CD54 (ICAM-1), CD58 (LFA-3), CD95 (Fas), and E-cadherin. Furthermore, when the SVpgC2a cell line was treated with T-cell derived cytokines, upregulation of CD40 expression was observed when the cells were treated with IL-4, whereas IFN-gamma caused upregulation in expression of CD40, CD54 and MHC class II. These buccal squamous epithelial cell lines, therefore, provide a good tool for analysing interactions between epithelium and T cells in vitro.

CD40 Antigens↗
PubMed1999

Gammadelta T cells in Behçet's disease (BD) and recurrent aphthous stomatitis (RAS).

The immunopathogenesis of BD is believed to be T cell-mediated. The objective of this study was to characterize the activation stage and cytokine profile of peripheral blood lymphocytes (PBL), with particular emphasis on gammadelta T cells. Venous blood was collected from 20 patients with BD, and for comparison, from 11 patients with RAS and from 15 healthy controls. Both the expression of activation markers (CD25, CD29, CD40 ligand, CD69 and HLA-DR) on freshly isolated PBL and T cell subsets, and the expression of intracellular cytokines (IL-4, IL-10, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha)) on mitogen-stimulated PBL and T cell subsets were analysed by double immunofluorescent staining and flow cytometry. Significantly decreased proportion of alphabeta T cells and increased proportion of gammadelta T cells, CD56+ cells and CD8+ gammadelta T cells were found in BD patients compared with healthy controls. This was also seen to a lesser extent in patients with RAS. Furthermore, in BD a significantly increased proportion of the gammadelta T cell population expressed CD69 and high levels of CD29 and were induced to produce IFN-gamma and TNF-alpha compared with healthy controls. In contrast, an increased percentage of gammadelta T cells from RAS patients was induced to produce IFN-gamma, but not TNF-alpha. These results indicate that in BD, activated gammadelta T cells, capable of producing IFN-gamma and TNF-alpha, are present in peripheral blood, suggesting that gammadelta T cells are dynamic and may be regulating immunopathogenic events.

Adult↗
PubMed1997

T-cell epitopes recognized within the 65,000 MW hsp in patients with IgA nephropathy.

IgA nephropathy (IgAN) is the commonest cause of glomerulonephritis and clinical exacerbation of IgAN is frequently associated with mucosal infection. T-cell receptor gamma delta (TCR gamma delta+) cells are increased in both the circulation and in renal biopsies of patients with progressive IgAN. We examined the hypothesis that specific peptides within the 65,000 MW heat-shock protein (hsp) might stimulate TCR gamma delta cells and play a part in the immunopathogenesis of IgAN. We studied T-cell proliferative responses stimulated by overlapping peptides derived from the sequence of mycobacterial 65,000 MW hsp. Three T-cell epitopes have been identified (peptides 51-65, 71-85 and 281-295). The three peptides have a synergistic effect and they stimulate significantly higher proliferation of T cells in patients with IgAN than in disease or healthy controls. This response was inhibited by monoclonal antibodies (mAb) to TCR gamma delta+ and human leucocyte antigen (HLA) class I, but not by mAb to HLA class II. The involvement of TCR gamma delta+ cells was confirmed by up-regulation of the proportion of TCR gamma delta+ cells when stimulated with the three specific peptides. We suggest that IgAN might be associated with mucosal infection by a variety of micro-organisms and that peptides within the microbial hsp cross-react with the homologous human hsp which may stimulate TCR gamma delta+ cells and play a part in the pathogenesis of IgAN.

Adult↗
PubMed1996

Role of gamma delta T cells in pathogenesis and diagnosis of Behcet's disease.

BACKGROUND: Behcet's disease (BD) is a multisystem disorder of unknown pathogenesis. The diagnosis is based on a set of international clinical criteria. Previous investigations have suggested that immunological cross-reactivity between peptides within streptococcal heat-shock proteins and human peptides might be involved in the pathogenesis of BD. We tested four peptides from mycobacterial heat-shock proteins to see if they specifically stimulated gamma delta T cells from BD patients. We then investigated this response to see whether it could be used as a laboratory test to diagnose BD. METHODS: We used a T-cell proliferative test to assay responses to four mycobacterial 65 kDa heat-shock-protein peptides and to four homologous peptides derived from the sequence of the human 60 kDa heat-shock protein. FINDINGS: We elicited significant gamma delta T-cell responses to the mycobacterial peptides in 25 (76%) of 33 patients with BD, compared with 2 (3.6%) of 55 controls with recurrent oral ulcers, systemic disease, or no disorders. The proportion of BD patients who had false-negative results decreased if the test was done during clinical manifestation of disease activity. There was a correlation between disease activity and T-cell responses. Four homologous peptides from human 60 kDa heat-shock protein also specifically stimulated T cells from patients with BD but with lower stimulation indices. INTERPRETATION: Activation of peripheral-blood mononuclear cells with the four heat-shock-protein peptides elicited significant T-cell proliferative responses by the gamma delta subset of T cells, which may regulate alpha beta T cells. Because these peptides have a high specificity for BD, this assay can be used as a laboratory diagnostic test for BD.

Adult↗
PubMed1996

Recognition of B-cell epitopes of the 65 kDa HSP in Behçet's disease.

B-cell epitopes of the mycobacterial 65 kDa heat shock protein (HSP) were mapped in sera from patients with Behçet's Disease (BD). A series of 47 overlapping synthetic peptides (15ers) derived from the sequence of the Mycobacterium tuberculosis 65 kDa HSP was used in ELISA. Significant increases in IgA and IgG antibody levels were observed with peptides 111-125, 154-172 and 311-326 in sera from BD, compared with those from controls. Homologous peptides derived from the sequence of the human mitochondrial 60 kDa HSP were then examined. Peptides 136-150 and 336-351 showed comparable results to the homologous mycobacterial peptides 111-125 and 311-326, respectively. The B-cell epitopes defined in this investigation overlap with the T-cell epitopes the authors have previously reported in BD. Inhibition studies are consistent with the view that antibodies to each of the three B-cell epitope peptides represent a small proportion of the total B-cell epitope repertoire elicited by the 65 or 60 kD HSP. Sequential antibody studies suggest that IgA and IgG antibody titres to one or all three peptides tested may increase during exacerbation of ocular disease. The functional role of these antibodies needs to be determined, but the peptides may be involved in the immunopathogenesis of BD as they can induce experimental uveitis in Lewis rats, which is a principal manifestation of BD.

Adolescent↗
PubMed1995

Lectin-carbohydrate interactions in disease. T-cell recognition of IgA and IgD; mannose binding protein recognition of IgG0.

Two disease associated lectin-carbohydrate interactions have been studied. (1) A T-cell surface lectin which binds IgA1 and IgD is expressed on CD4+ and CD8+ T-lymphocytes in a number of diseases including systemic lupus erythematosus, rheumatoid arthritis (RA), Behcet's disease and IgA nephropathy. We have demonstrated that calcium independent binding to this receptor is mediated by the O-linked disaccharide Gal beta 3GalNAc which is associated with the hinge regions of both IgA1 and IgD. (2) In rheumatoid arthritis the proportion of IgG0 glycoform populations lacking terminal galactose increases. We have shown that terminal GlcNAc residues on oligosaccharides in the Fc region of IgG0 can bind to the C-type lectin, serum mannose binding protein, and thus activate the classical complement pathway. This provides a mechanism of activation of the complement system not available to the other classes of IgG glycoforms.

Carbohydrate Metabolism↗
PubMed1994

The expression of carbohydrate antigens in activated T cells and in autoimmune diseases.

Cell surface carbohydrate antigens have been implicated in cell differentiation and maturation and may play a role in immunoregulation. The expression of carbohydrates in peripheral blood lymphocytes (PBL) was studied by double immunofluorescence flow cytometry, using MoAbs CT1 and CT2 but only a small proportion of cells bound these MoAbs. MoAbs CT1, CT2 and the lectin vicia villosa (VV) which share specificity for Gal NAc were then used to examine lymphocytes from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Behcet's disease (BD) and IgA nephropathy. A significant increase in MoAbs CT1 CT2 and VV binding CD4 or CD8 cells was found only with lymphocytes from patients with SLE. However, MoAbs CT or VV binding lymphocytes from healthy subjects were significantly up-regulated by activation with a mitogen (PHA), cross-linked anti-CD3 MoAb or a common antigen (65kDa heat shock protein), suggesting that an increased proportion of T cells expressing these carbohydrates results from any of the three types of lymphocyte activating agents. Inhibition studies were then carried out to determine the relationship between the MoAbs CT1 and CT2, VV and GalNAc. Indeed, VV binding to T cells was significantly inhibited by either MoAbs CT1 or CT2, or GalNAc but not GlucNAc, suggesting that VV shares a common binding site with MoAb CT and that GalNAc may constitute one of the sugar receptors. Investigations of lymphocytes from adult peripheral blood in health and disease suggest that carbohydrate antigens may play a role in activation and immunoregulation.

Adult↗
PubMed1994

A human T-cell receptor recognizes 'O'-linked sugars from the hinge region of human IgA1 and IgD.

A receptor which binds secretory IgA (sIgA) is expressed on human T cells from patients with systemic lupus erythematosus, rheumatoid arthritis, Behcet's syndrome and IgA nephropathy and on normal T cells following phytohaemagglutinin (PHA) stimulation. The specificity of this receptor was initially probed with a panel of normal serum immunoglobulins in competitive inhibition assays with sIgA using two-colour immunofluorescence. While the receptor showed the strongest affinity for IgA1 (IC(50)10(-6) M), IgD which has a similarly glycosylated hinge region to IgA1, also bound to the receptor (IC50 10(-5) M). IgA2, which lacks the 'O'-glycosylated hinge region, did not significantly inhibit the binding at these concentrations suggesting that the IgA determinants for this receptor might be the oligosaccharides present in the hinge region of IgA1. IgA1 has up to 10 'O'-linked oligosaccharides and four N-linked oligosaccharides per molecule. In order to probe the role of the 'O'-linked hinge sugars in the binding event, a sugar library was prepared from IgA1 by a procedure designed to release 'O'-linked oligosaccharides preferentially, and to retain them in the natural closed ring formation. The sugars were released by hydrazinolysis at 65 degrees and the resulting oligosaccharide library analysed by high voltage paper electrophoresis (HVE) and P4 gel permeation chromatography. Competitive inhibition studies demonstrated that both the library and the individual 'O'-linked sugars associated with IgA1 were implicated in the binding of IgA1 to this receptor (IC50 between 1 x 10(-5) M and 6 x 10(-5) M). Within this range the individual sugars showed small differences in their affinity for the receptor in the following order: Gal beta 3GalNAc = NeuNAc2 alpha 3(6)Gal beta 3GalNAc > NeuNAc2 alpha 3(6)Gal beta 3[NeuNAc2 alpha 6]GalNAc > or = GalNAc.

Binding, Competitive↗