摘要:

Objective:To identify and characterize an open reading frame (ORF) in association with its mRNA and a coding protein recognized by anti-human herpesvirus 8 (HHV-8) monoclonal antibody B291.Study Design/Methods:The antigen detected by B291 was characterized by immunofluorescence method, Western blot analysis, laser confocal microscopy, and immunohistology. cDNA of the protein was identified by immunoscreening the HHV-8 cDNA library with B291 and sequenced. Structure and kinetics of the mRNA expression was investigated by 5′,3′ rapid amplification of cDNA ends (RACE) and Northern blot analysis.Results:Viral interferon regulatory factor (vIRF; ~50 kd) was a protein recognized by B291. It was detected in 12-0-tetradecanoyl phorbol-13 acetate (TPA)-induced, but not uninduced, HHV-8-infected cell lines (BCBL-1 and BCP-1) and the tumor cells obtained from a SCID mouse injected with uninduced BCBL-1. The expression of vIRF was predominantly in the nucleus and was partially diminished by phosphonoformic acid (PFA) treatment, whereas the mRNA (~2.4 kb) was accumulated.Conclusions:vIRF is an early protein expressed in the nucleus and may be involved in Kaposi's sarcoma tumor formation.Journal of Human Virology 1999;2:63-71 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:To investigate some of the cellular consequences of HIV-1 Tat expression in human astrocytic cells. This study is based on evidence that cellular factors play a critical role in facilitating transcriptional activation by Tat through its interaction with thetrans-acting-response (TAR) RNA element and upstream HIV-1 long terminal repeat (LTR) promoter binding site.Study Design-Methods:Using the previously established astrocytic cell line of human origin stably transfected with Tat cDNA, we analyzed the formation of a nucleoprotein complex consisting of three cellular proteins associated with TAR RNA using ultraviolet (UV) crosslinking and glutathione-S-transferase (GST) pull-down assays.Results:UV crosslinking experiments reveal that the molecular masses of the proteins range from 50 to 62 kd. Transient transfection studies demonstrate that the presence of these proteins correlates with the ability of Tat to transactivate the HIV-1 LTR in the absence of the trinucleotide bulge, a region within TAR that has been shown to be important for Tat-TAR interaction. A combination of GST pull-down assays and RNA binding studies demonstrates that the 50-kd protein interacts with both Tat and TAR and is likely to be NF-&kgr;B p50.Conclusions:Taken together, these data suggest that in the absence of a functional Tat binding site such as TAR (which tethers the viral protein to the RNA), cellular protein NF-&kgr;B p50 may be able to bring Tat into the RNA binding complex. Tat has been shown to activate expression of a variety of cellular genes that may not contain a binding site for Tat but do contain binding sites for NF-&kgr;B family members. The results presented in this study may be relevant for Tat-mediated transactivation of cellular as well as viral genes, both of which might contribute to the central nervous system damage associated with HIV-1 infection.Journal of Human Virology 1999;2:72-80 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Because of the important medical consequences of human cytomegalovirus (HCMV) infection in human immunodeficiency virus (HIV)-infected individuals, we wanted to understand the molecular interactions that occur during coinfection. Specifically, in this study, we wanted to identify the transactivating target sequences on the HIV long terminal repeat (LTR) that responded to HCMV infection.Study Design/Methods:In this study, we transfected the HIV-LTR into human fibroblasts and then mapped the regulation of this promoter following HCMV infection and cotransfection with the HCMV immediate-early (IE) gene product IE2-86. In addition, we examined IE2-86 binding to specific sequences in the HIV-LTR by electrophoretic mobility shift assay.Results:Our results documented that HCMV and IE2-86 could transactivate the HIV-LTR. In mapping the regions of the HIV-LTR that IE2-86 transactivates, we identified discrete target sequences between -120 and -20 that are the major transactivating regions for the IE2-86-mediated effects and determined that IE2-86 could specifically bind to several discrete sequences within this region of the HIV-LTR.Conclusions:Our discovery of the binding of IE2-86 to the HIV-LTR, coupled with its ability to transactivate the HIV-LTR and induce cellular transcription factors, points to potential molecular mechanisms used by HCMV to upregulate the HIV life cycle and, consequently, exacerbate the conditions observed in individuals co-infected with HCMV and HIV.Journal of Human Virology 1999;2:81-90 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:To characterize replication patterns and cytopathic effects during human cytomegalovirus (HCMV) infection of brain cells.Design:Primary human mixed glial/neuronal cells, as well as purified microglial, astroglial, and enriched neuronal cell cultures, were infected with HCMV strains AD169 and RC256 to determine the ability of the different brain cell types to support viral replication.Results:Mixed glial/neuronal cell cultures were fully permissive for viral replication. Based on previous studies, we hypothesized that human microglial cells would preferentially support productive HCMV replication. However, HCMV did not replicate or display genomic expression in microglial cells. In contrast, primary astrocytes were fully permissive and displayed HCMV-induced cytopathic effects resulting in cell death. In highly enriched neuronal cultures, productive infection and viral expression occurred only in scattered astrocytes. Early in the infection, apoptotic plasma membrane changes were induced in astrocytes. However, nuclear fragmentation was not apparent until later during the course of infection.Conclusions:These results suggest that HCMV possesses astrocytotropic properties that confer preferential expression and cytopathic replication in astrocytes over microglia or neuronal cells. Apoptotic cell death, which is a result of HCMV infection, appears to be delayed until peak viral replication has occurred.Journal of Human Virology 1999;2:91-101 © Lippincott Williams, & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:The pathogenesis of coxsackievirus B3 (CVB3)-induced myocarditis was investigated in immunocompetent C57BL/6 and MHC class II knockout mice with identical genetic backgrounds.Study Design/Methods:We analyzed the histology and immunohistology of myocardial injury, the replicating virus titer, and antibody response in the early and late phase of disease.Results:CVB3-infected C57BL/6 mice showed acute myocarditis, with spontaneous healing, virus elimination, anti-CVB3 IgM/IgG production, and neutralizing antibody response. In contrast, MHC class II knockout mice developed less severe acute myocarditis, persistence of infiltrations and strong fibrosis, virus persistence, and weak IgG response, with absence of virus neutralizing antibodies.Conclusions:Immunodeficient organisms are more susceptible to long-term heart muscle injuries after infection with CVB3. The presence of CD4+T cells are necessary to prevent the development of chronic disease.Journal of Human Virology 1999;2:102-114 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:A high prevalence of GB virus C (GBV-C)/hepatitis G virus (HGV) RNA and E2 antibodies is observable in human immunodeficiency virus type 1 (HIV-1)-infected individuals in Belgium, including intravenous drug users (IDUs), in whom the highest prevalence is observed. A molecular analysis of GBV-C/HGV could give indications on the origin of this infection in IDUs.Methods:We directly sequenced 7 GBV-C/HGV isolates from this IDU population and performed a phylogenetic analysis comparing the results to known GBV-C/HGV sequences.Methods:We directly sequenced 7 GBV-C/HGV isolates from this IDU population and performed a phylogenetic analysis comparing the results to known GBV-C/HGV sequences.Results:All 7 isolates were GBV-C/HGV genome type 2. Three were found to be subtype 2a, and 4 belonged to the 2b subtype. No specific clustering was observed for strains obtained from IDUs in Belgium, and they were interspersed between other sequences with long branch lengths.Conclusion:Based on our results, it is unlikely that the IDUs were infected recently by GBV-C/HGV from a common ancestral virus.Journal of Human Virology 1999;2:115-120 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID