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  • Cytomegalovirus
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  • 11
    Language: English
    In: Trends in Microbiology, 2003, Vol.11(4), pp.171-178
    Description: Human cytomegalovirus (HCMV) retinitis frequently occurs in severely naturally and iatrogenically immunocompromised patients. It has been shown that the immune-privileged retinal pigment epithelium (RPE) is a major site of persistent HCMV. Recently, evidence has accumulated to show that HCMV immediate early (IE) gene expression in RPE cells deviates ocular antiviral inflammation via FasL. Moreover, unlike in other cell types, the HCMV major IE1/2 enhancer promoter (MIEP) resists activation by proinflammatory stimuli mediated by the transcription factor NF- Kappa B. However, tumor necrosis factor- alpha (TNF- alpha ) and interferon- gamma (IFN- gamma ) found at elevated levels in transplant recipients and AIDS patients with retinitis sensitize RPE cells and other retinal cells to FasL-mediated apoptosis, thus contributing to retina destruction and necrosis rather than inflammation. These specific features of RPE cells in conjunction with deregulated immune responses of immunocompromised patients seem to contribute to virus persistence and pathogenesis within the immune-privileged ocular retina.
    Keywords: Biology
    ISSN: 0966-842X
    E-ISSN: 1878-4380
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  • 12
    Language: English
    In: International Journal of Cancer, 01/03/1996, Vol.65(1), pp.90-96
    Description: Human neuroblastoma cell line UKF-NB-4 persistently infected with human cytomegalovirus (HCMV) strain AD169 was established to study the effects of long-term HCMV infection on virus production and phenotypic characteristics of tumour cells. The cells designated UKF-NB-4 super(AD169) were subcultured (80 subcultures) over a period of more than 2 years after initiation of infection. UKF-NB-4 super(AD169) cells continued to produce infectious virus in successive passages, with a titre ranging from 9 x 10 super(3) to 1 x 10 super(5) and from 2 x 10 super(1) to 2 x 10 super(2) plaque-forming units per 10 super(6) cells and 1 ml culture medium, respectively; 10-20% of the cells produced HCMV-specific antigens, while 6-13% produced infectious virus progeny. The number of HCMV-specific DNA copies ranged from 9 x 10 super(4) to 9 x 10 super(6) per 10 super(6) cells. Transmission electron microscopy confirmed the productive nature of HCMV infection. UKF-NB-4 super(AD169) cultures proliferated, with population doubling time ranging from 24.5 to 26.6 hr (19.5 to 20.3 hr for UKF-NB-4) and cell viability from 79% to 85% (91-96% for UKF-NB-4). Significantly lower amounts of tyrosine hydroxylase and decreased activity for dopamine- beta -hydroxylase than in uninfected cells were observed in UKF-NB-4 super(AD169) cells. However, the expression of N-myc oncoprotein was significantly increased in persistently infected cultures. Our results show that long-term productive HCMV infection of UKF-NB-4 cell line is associated with the modulation of phenotypic properties, which may be related to the biological behaviour of neuroblastoma cells.
    Keywords: Cytomegalovirus ; Cytomegalovirus ; Neuroblastoma Cells ; Man ; Tumor Cells ; Phenotyping ; Neuroblastoma Cells ; Man ; Tumor Cells ; Phenotyping ; Neurovirology ; Virus Behavior in Cell Culture ; Tyrosine 3-Monooxygenase ; Dopamine Beta -Monooxygenase ; N-Myc Protein ; Tyrosine 3-Monooxygenase ; Dopamine Beta -Monooxygenase ; N-Myc Protein ; N-Myc Protein ; Dopamine Beta -Monooxygenase ; Tyrosine 3-Monooxygenase;
    ISSN: 00207136
    E-ISSN: 10970215
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  • 13
    Language: English
    In: Medical Microbiology and Immunology, 2009, Vol.198(4), pp.257-262
    Description: A coupled luminescent method (CLM) based on glyceraldehyde-3-phosphate dehydrogenase released from injured target cells was used to evaluate the cytotoxicity of antigen-specific HLA class I-restricted CTLs. In contrast to established methods, CLM does not require the pretreatment of target cells with radioactive or toxic labeling substances. CTLs from healthy HLA-A2 positive donors were stimulated by autologous dendritic cells (DCs) pulsed with HLA-A2 restricted HCMV-pp65 nonamer peptides. HLA-A2 positive T2 cells or autologous monocytes pulsed with HCMV-pp65 nonamer peptide served as target cells. Lysis was detected only in HCMV-pp65-pulsed target cells incubated with CTLs from seropositive donors stimulated by HCMV-pp65-pulsed DCs. After 3 days, stimulation 38% of T2 cells and 17% of monocytes were lysed at an effector to target ratio of 8:1. In conclusion, CLM represents a highly sensitive, fast, material-saving and non-toxic/non-radioactive method for the measurement of antigen-specific CTL cytotoxic activity.
    Keywords: Cytotoxic T lymphocytes ; HLA-A2-restricted peptide ; Human cytomegalovirus ; Cytotoxicity ; Coupled luminescent method ; Dendritic cells
    ISSN: 0300-8584
    E-ISSN: 1432-1831
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  • 14
    In: Cardiovascular Research, 2008, Vol. 77(3), pp.544-550
    Description: AIMS: The endothelium represents a natural site of human cytomegalovirus (HCMV) infection involved in viral spreading and persistence. Moreover, HCMV infection of endothelial cells has been associated with different pathological conditions of the cardiovascular system. Here, the influence of the antiepileptic drug valproic acid (VPA) was investigated on HCMV replication in human umbilical vein endothelial cells alone or in combination with the antiviral drugs ganciclovir, cidofovir or foscarnet.METHODS AND RESULTS: HCMV replication was observed by immunostaining for viral antigens and by virus yield assay. Protein expression and phosphorylation were examined by western blot. Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye reduction assay. Therapeutic VPA concentrations (〈 or =1 mM) increased HCMV immediate early antigen, late antigen, and viral titres of different endotheliotropic and non-endotheliotropic HCMV strains in a concentration- and time-dependent manner up to 30-fold. Moreover, VPA impaired the antiviral activity of the anti-HCMV drugs ganciclovir, cidofovir, and foscarnet. VPA inhibits histone deacetylases (HDAC) and induces HDAC-independently extracellular signal-regulated kinases 1/2 (ERK 1/2) phosphorylation in endothelial cells. Both effects observed, HCMV stimulation and interference with antiviral drugs, depend on HDAC inhibition but not on ERK 1/2 phosphorylation.CONCLUSION: These findings suggest to carefully monitor the frequency of HCMV reactivation in cardiovascular patients treated with VPA (or other HDAC inhibitors) in comparison to control individuals.
    Keywords: Human Cytomegalovirus ; Antiviral Therapy ; Endothelium
    ISSN: 0008-6363
    E-ISSN: 1755-3245
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  • 15
    In: Transplantation, 1996, Vol.61(12), pp.1763-1770
    Description: Transplantation-related pathogenic factors such as ischemia or allograft-directed inflammation are associated with oxidative changes that might lead to cellular oxidative stress. The aim of this study was to investigate the impact of oxidative stress on: (1) CMV replication in cultured human endothelial cells and (2) the stimulation of endothelial cells by proinflammatory cytokines. Both pathomechanisms are known to contribute to graft rejection crises in vivo. Oxidative stress was induced in endothelial cell cultures with 10-200 μM buthionine sulfoximine. Western blotting showed a significant increase in the production of CMV-specific immediate early and late proteins in buthionine sulfoximine-treated cultures. Immunocytochemical staining suggested that this effect was caused by increased numbers of CMV antigen expressing cells (66% immediate early; 78%, late). Quantitative polymerase chain reaction for CMV-specific DNA and virus titration revealed that enhanced viral replication levels correlated with increased virion production. As a measure for the endothelial cell activation status, the surface expression of HLA-ABC and HLA-DR and adhesion molecules(ICAM-1, ELAM-1, VCAM-1) was quantified by fluorometric methods. Whereas oxidative stress alone did not modulate any surface molecule expression, the IFN-γ-mediated expression of HLA-ABC and HLA-DR and the IL-1-mediated expression of ICAM-1, but not of ELAM-1 and VCAM-1 (IL-1+TNF-α), was amplified. Interestingly, the amplification of HLA molecule expression was even higher in CMV-infected endothelial cells. This study provides evidence that oxidative stress contributes to the regulation of CMV replication, virus shedding, and the activation of endothelial cells by proinflammatory cytokines as it is observed in transplant recipients.
    Keywords: Human Cytomegalovirus ; Human Cytomegalovirus ; Endothelium ; Replication ; Oxidation ; Stress ; Man ; Endothelium ; Replication ; Oxidation ; Stress ; Man ; Viruses ; Immune Response & Immune Mechanisms ; Cytokines ; Cytokines ; Cytokines;
    ISSN: 0041-1337
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  • 16
    In: Transplantation, 1999, Vol.68(11), pp.1753-1761
    Description: BACKGROUND.: Cytomegalovirus (CMV) infection is associated with acute and chronic allograft rejection. We have recently shown that rat CMV increases portal inflammation and bile duct destruction in a model of rat liver allograft rejection. Desferrioxamine (DFO), an iron chelator and antioxidant, has recently been demonstrated to have antiviral as well as immunomodulatory effects in vitro. We therefore investigated whether DFO inhibits (a) CMV infection and (b) graft destruction in our rat model. METHODS.: One day after liver transplantation, PVG (RT1) into BN(RT1), the rats were infected with rat CMV (RCMV, Maastricht strain; 10 plaque-forming units i.p.). The effects of 100 mg/kg body weight and 200 mg/kg body weight DFO were examined. RESULTS.: In the untreated group, the grafts were uniformly RCMV culture-positive. In the group receiving 200 mg/kg DFO, RCMV replication was effectively inhibited. Inflammatory response in the graft, and especially the number of macrophages, was significantly reduced by DFO. Portal inflammation and bile duct destruction were also significantly reduced. In the untreated group, the bile duct epithelial cells were found to be strongly positive for tumor necrosis factor-α and this expression was clearly decreased by DFO. In addition, DFO significantly inhibited vascular cell adhesion molecule-1 expression on sinusoidal endothelial cells. CONCLUSIONS.: Our in vivo transplant study strongly supports the inhibitory effects of metal chelators on CMV infection and their possible usefulness in the treatment of CMV-induced pathogenic changes.
    Keywords: Cytomegalovirus ; Graft Rejection ; Liver ; Allografts ; Inflammation ; Bile Duct ; Graft Rejection ; Liver ; Allografts ; Inflammation ; Bile Duct ; Desferrioxamine ; Desferrioxamine ; Rat Cytomegalovirus ; Allograft ; Animal Models & Experimentally-Induced Viral Infections ; Rats ; Immunology ; Desferrioxamine ; Immunology ; Rat Cytomegalovirus ; Rats;
    ISSN: 0041-1337
    E-ISSN: 15346080
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  • 17
    Language: English
    In: International Journal of Molecular Medicine, February 2004, Vol.13(2), pp.327-331
    Description: Recently, we reported that thrombin specifically stimulates protease-activated receptor-1 (PAR-1) signaling in RPE entailing inhibition of Sp1 dependent HCMV replication. We now studied whether thrombin modulates the expression of the proinflammatory cytokine/chemokines IL-6 and IL-8 in mock- and cytomegalovirus-infected human retinal pigment epithelial cells (RPE). Our data show that thrombin/PAR-1 stimulates IL-6 and IL-8 gene transcription and protein secretion in both mock- and HCMV-infected RPE. Thrombin/PAR-1-mediated signaling stimulated PKC and NF-κB-dependent IL-6 and IL-8 gene expression via phosphoinositide 3-kinase and further downstream via p42/44 and p38 MAPKs. Thus, thrombin/PAR-1-mediated IL-6/IL-8 gene expression is uncoupled from Sp1 inhibition and may support proinflammatory pathomechanisms probably involved in hemorrhage/HCMV retinitis progression.
    Keywords: Cytomegalovirus Infections -- Metabolism ; Interleukin-6 -- Genetics ; Interleukin-8 -- Genetics ; Pigment Epithelium of Eye -- Metabolism ; Thrombin -- Metabolism;
    ISSN: 1107-3756
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  • 18
    Language: English
    In: Trends in Molecular Medicine, 2004, Vol.10(1), pp.19-23
    Description: Recently, the term oncomodulation has been proposed to express the ability of human cytomegalovirus (HCMV) to modify tumor cell biology, a phenomenon that is independent from transformation. Because past studies have failed to show that HCMV can transform normal human cells, HCMV has not been regarded as an oncogenic tumor virus. However, recent investigations have revealed a high frequency of HCMV in tumor cells of malignancies such as colon cancer, malignant glioma, prostatic intraepithelial neoplasia, and carcinoma. Data from experiments with HCMV-infected tumor cell lines have highlighted the oncomodulatory potential of HCMV and provided important insights into the patho- mechanisms associated with aberrant signaling pathways and transcription factor and/or tumor suppressor function of the host cell.
    Keywords: Medicine ; Biology
    ISSN: 1471-4914
    E-ISSN: 1471-499X
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  • 19
    Language: English
    In: Medical Microbiology and Immunology, 2004, Vol.193(4), pp.205-208
    Description: The underlying mechanisms leading to persistence of human cytomegalovirus (HCMV) in the immune privileged retina are not fully understood. This in vitro study was done to evaluate the influence of HCMV-infected retinal glial cells on epithelial barrier functions. Glial cells derived from human eyes were cultured and infected with the clinical HCMV isolate Hi91. Supernatants of mock (GS mock ) and Hi91 (GS Hi91 ) -infected glial cells were collected at 72 h post inoculation and used for incubation of CaCo-2 cells grown in transwell chambers. Transepithelial electrical resistance (TER) was analyzed as a measure of epithelial integrity. Virus-free GS Hi91 but not GS mock increased TER from 250 Ω/cm 2 to more than 1,000 Ω/cm 2 within 2 h. Increased TER values were measured up to 48 h ( n =3). No changes in TER were observed when conditioned supernatants from HCMV-infected human foreskin fibroblasts were used. No evidence of GS Hi91 -induced modification of β-catenin (zonula adherens) or occludin and ZO-1 (zonula occludens) was found. Our results suggest that HCMV-infected glial cells may support epithelial barrier functions by a yet unknown mechanism. Our findings may help to explain the ocular persistence of HCMV and the maintenance of ocular immune privilege early in infection.
    Keywords: Human cytomegalovirus ; Immune privilege ; Junction molecules ; Retinitis
    ISSN: 0300-8584
    E-ISSN: 1432-1831
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  • 20
    Language: English
    In: Biochemical and Biophysical Research Communications, 2005, Vol.326(2), pp.395-401
    Description: In a model of human neuroblastoma (NB) cell lines persistently infected with human cytomegalovirus (HCMV) we previously showed that persistent HCMV infection is associated with an increased malignant phenotype, enhanced drug resistance, and invasive properties. To gain insights into the mechanisms of increased malignancy we analyzed the global changes in cellular gene expression induced by persistent HCMV infection of human neuroblastoma cells by use of high-density oligonucleotide microarrays (HG-U133A, Affymetrix) and RT-PCR. Comparing the gene expression of different NB cell lines with persistently infected cell sub-lines revealed 11 host cell genes regulated in a similar manner throughout all infected samples. Nine of these 11 genes may contribute to the previously observed changes in malignant phenotype of persistently HCMV infected NB cells by influencing invasive growth, apoptosis, angiogenesis, and proliferation. Thus, this work provides the basis for further functional studies.
    Keywords: Neuroblastoma ; Human Cytomegalovirus ; Microarray Analysis ; Oncomodulation ; Biology ; Chemistry ; Anatomy & Physiology
    ISSN: 0006-291X
    E-ISSN: 1090-2104
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