| 1. |
- Bereczky-Veress, Biborka, et al.
(author)
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Host strain-dependent difference in susceptibility in a rat model of herpes simplex type 1 encephalitis.
- 2008
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In: Journal of neurovirology. - : Springer Science and Business Media LLC. - 1538-2443 .- 1355-0284. ; 14:2, s. 102-18
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Journal article (peer-reviewed)abstract
- Herpes simplex encephalitis (HSE) is characterized by severe focal brain inflammation leading to substantial loss of nervous tissue. The authors established a model of Herpes simplex virus type 1 (HSV)-1-induced acute encephalitis in the rat by injecting into the whiskers' area a virus strain isolated from a fatal human HSE case. The model might resemble natural propagation of HSV-1 in humans; spreading from the mouth and lips via the trigeminal nerve to trigeminal ganglia and subsequently entering the central nervous system (CNS). HSV-1 infected Dark Agouti (DA) rats developed a well-synchronized disease and died 5 days after inoculation. HSV-1 detection by quantitative polymerase chain reaction (qPCR), virus isolation and immunohistochemistry, magnetic resonance imaging, and histopathological examination verified dramatic encephalitis mainly in the brainstem, but also in the olfactory bulb and other segments of the brain of diseased rats. In contrast, Piebald Virol Glaxo (PVG) rats were completely resistant to disease, displaying a more rapid clearance of peripheral infection and no evidence of virus entering into neither the trigeminal ganglia nor the CNS. These results suggest a regulation of susceptibility to HSV-1-induced encephalitis at the level of peripheral infection and subsequent neuronal uptake/transport of the virus. This provides a basis for future positioning of genetic polymorphisms regulating HSE and for dissection of important pathogenetic mechanisms of this severe human disease.
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| 2. |
- Sabri, Farideh
(author)
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Astrocytes during HIV infection of the brain : relevance for neuropathogenesis
- 2000
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Doctoral thesis (other academic/artistic)abstract
- The overall aim of the present thesis was to characterize the role that astrocytes play for neuropathogenesis of AIDS dementia complex (ADC). We studied whether it is possible to derive the phenotype of HIV-1 virus by analyzing V3 sequences. Our analysis, conducted by comparing V3 sequences and replicative properties of 9 HIV-1 isolates (from four patients), indicated that the shift from non-syncytium inducing to syncytium inducing phenotype did not always correlate with an increase of V3 net charge. Thus extrapolation of the biological properties of HIV-1 variants from V3 sequences it is not always possible. The frequency of ADC in cohorts of patients treated with zidovudine (AZT) is very low. We analyzed whether AZT resistant strains could be found in the CSF and blood of six patients treated with AZT. Blood isolates resistant to AZT have been shown to be mutated at positions 41, 67, 70, 215 and 219 of the reverse transcriptase gene. In our study, we could show that in the isolates from 4 (of 6) patients different pattern of mutations were found in CSF isolates as compared to what found at the same time point in blood. These results show that AZT reaches the CSF and give support to the different evolution of the HIV-1 virus in the brain and systemic compartments. In order to further clarify the role of astrocytes in HIV-1 neuropathogenesis, we infected primary fetal astrocytes with 26 primary HIV-1 isolates with defined biological properties, including isolates with slow/low and rapid/high phenotypes and different chemokine receptor usage. We demonstrated that human fetal astrocytes could be infected in vitro with primary HIV-1 isolates independently of their biological phenotype and chemokine receptor usage. Viral replication was not sustained and stimulation with the cytokine IL-1[beta] promoted virus production in astrocytes. The HIV-1 receptor(s) on astrocytes was studied by analysing CD4 expression and chemokine receptor mRNAs and protein expression in primary astrocytes. We could amplify the mRNAs for CXCR4, CXCR2, CCR5, CCR3, CCR2 and the orphan receptors APJ and Bonzo/STRL33/TYMSTR, although the astrocytes did not express any of these receptors (nor CD4) at the cell surface. This result was confirmed when the presence of chemokines RANTES, MIP-1[alpha] MIP-1[beta], MCP-1 and SDF-1[beta] in culture did not induce mobilization of intracellular calcium influx in astrocytes. Therefore we suggest that primary HIV-1 isolates infect astrocyte independently of CD4 and chemokine receptors. Since neuropathological studies conducted on AIDS brains have shown that astrocytes are activated and undergo apoptosis, we focused our attention on molecules involved in the regulation of apoptosis. We analyzed the expression of Fas and Fas ligand (FasL) in brain tissues obtained from HIV-1 infected subjects, including asymptomatic HIV-1 carriers and AIDS patients, and controls. The amount of Fas transcripts amplified from the AIDS brains was higher than from the brain of asymptomatic carriers. The FasL transcripts were expressed in the brain of patients who had developed AIDS and of one asymptomatic carrier. Fas was predominantly expressed by reactive astrocytes and FasL by CD3+ T-cells located in proximity of reactive astrocytes. These results indicate that the Fas/FasL pathway may be involved in apoptosis dysregulation in the brain during AIDS. This possibility was reinforced by the interesting finding that the levels of soluble Fas (sFas) and sFasL were significantly higher in the CSF of patients with ADC (n=29) as compared to ADC negative patients (n=22) and HIV-1 negative controls (n=39). A decline of CSF sFas levels was observed in patients treated with highly active antiretroviral therapy (HAART) in parallel to the reduction of viral load in CSF. Taken together, theses results suggest that sFas and sFasL may represent useful markers for ADC diagnosis and for monitoring immune activation in the brain during HAART. We also explored the possibility that upregulation of Fas expression during HIV-1 infection would render these cells susceptible to bystander cell killings executed through virus-specific cytotoxic T-cells (CTLs) invading the brain. Bystander cell killing has been shown to occur through the Fas-Fas L pathway in different experimental conditions. The response of a panel of astroglioma cell lines and primary human astrocytes to supernatants from peptide activated CTLs was studied. Our results showed that virus specific CTLs can produce soluble factors capable of inducing apoptosis in 5110 astroglioma cell lines., Fas L is not the only factor involved in this pathway of cell damage. Our results showed that in the supernatant from activated CTLs are present additional factor(s) that can mediate the apoptosis of astroglioma lines, alone or in synergy with TNF-[alpha]
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| 3. |
- Sabri, Farideh, et al.
(author)
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Soluble factors released by virus specific activated cytotoxicT-lymphocytes induce apoptotic death of astroglioma cell lines
- 2003
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In: Brain Pathology. - : Wiley. - 1015-6305 .- 1750-3639. ; 13:2, s. 165-175
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Journal article (peer-reviewed)abstract
- Astrocytomas and astrogliomas represent the most common types of primary tumors in human central nervous system and are associated with high mortality due to the absence of efficient therapy. Here we demonstrate that, upon antigen-specific activation, cytotoxic T-lymphocytes (CTLs) secrete products that inhibit proliferation and induce apoptosis in a significant proportion of astroglioma cell lines. This effect is tumor specific in that normal cultured astrocytes do not develop apoptotic changes upon exposure to supernatant of activated CTLs. Experiments with purified lymphokines and lymphokine specific blocking antibodies indicate that synergistic activities of tumor necrosis factor (TNF)-alpha and interferon (INF)-gamma are required for the apoptosis inducing effect on some astroglioma cell lines. However, this effect appears to be dependent on additional factors produced by activated CTLs. Our results suggest that local application of factors released by activated CTLs or induction of CTL migration and activation in the tumor site may have a therapeutic effect in patients with astrogliomas.
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| 4. |
- Sköldenberg, Birgit, et al.
(author)
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Incidence and pathogenesis of clinical relapse after herpes simplex encephalitis in adults.
- 2006
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In: Journal of neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 253:2, s. 163-70
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To study the occurrence of relapse of herpes simplex encephalitis (HSE) and to find out whether soluble activity markers in cerebrospinal fluid (CSF) indicate direct viral or immune- mediated events. METHODS: A consecutive series of 32 adult survivors of HSE were followed to determine the incidence of clinical relapse of HSE. Four patients had neurological deterioration interpreted as relapsing HSE. Four non-relapsing HSE cases were selected as matched controls. Fifty nine batched, paired CSF and serum samples from the eight HSE patients were analysed for soluble activity markers, predominantly cytokines and mediators (interferon-gamma, soluble CD8, tumour necrosis factor-alpha, and interleukin-10), amount of HSV-DNA and markers of glial and neuronal destruction (neurofilament protein, glial fibrillary acidic protein, S-100-beta, and neuron specific enolase). RESULTS: Relapse of HSE was diagnosed in 3 of 26 (12 %) acyclovir-treated patients (5 episodes during 6.1 years of followup) and in 1 of 6 vidarabine-recipients. All relapses occurred from 1 to 4 months after acute HSE, except for a second relapse after 3.3 years in one patient. Computer tomography at relapses revealed few abnormalities apart from those found during the primary disease. Intravenous acyclovir and corticosteroids were given for 7-21 days in all the relapse patients. All relapse patients seemed to recover to the pre-relapse condition. HSV-DNA was demonstrated in CSF in all patients during the acute stage but not in any of 13 CSF samples taken during relapse phases. The HSV viral load during the acute stage of HSE was not higher or of longer duration in the relapsing patients than in the non-relapsing HSE controls. The levels of sCD8 were increased in nearly all CSF samples tested with peaks of sCD8 at one month of acute HSE. In all episodes of relapse, sCD8 peaks were detected during the first week at high levels. CSF levels of neuron-specific enolase, S-100 and glial fibrillary acidic protein were markedly lower at relapse than at the acute stage of HSV-1 encephalitis. CONCLUSION: The lack of demonstrable HSV DNA in CSF, the lack of acute CSF signs and the lack of signs of neural and glia cells destruction indicate that a direct viral cytotoxicity is not the major pathogenic mechanism in relapse. Instead, the pronounced CSF proinflammatory immunological response and the relative lack of CSF anti-inflammatory cytokine IL-10 response suggest immunologically-mediated pathogenicity.
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