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

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:Human herpesvirus 8/Kaposi's sarcoma herpesvirus (HHV-8/KSHV) contains, in addition to genes required for viral replication, an unique set of nonstructural genes which may be part of viral mimicry and contribute to viral replication and pathogenesis in vivo. Among these, HHV-8 encodes four open reading frames (ORFs) that show homology to the transcription factors of the interferon regulatory factor (IRF) family. In this study we demonstrate that one of these ORFs (vIRF-2) encodes a protein with mobility of 18 kd which has distinct pattern of expression and properties from the cellular IRFs and the previously characterized vIRF-1.Methods:We cloned vIRF-2 by polymerase chain reaction (PCR) and studied its expression by Northern blot and reverse transcription-polymerase chain reaction (RT-PCR). Biologic activities were tested by chloramphenicol acetyltransferase (CAT) assay in transiently transfected mammalian cells. We characterized its DNA binding specificity by electrophoretic mobility shift analysis (EMSA) and its protein-protein interactions by in vitro pull-down assay.Results:Although low levels of vIRF-2 mRNAs can be detected in the HHV-8-positive BCBL-1 tumor cell line, 12-0-tetradecanoylphorbol-13-acetate (TPA) treatment does not stimulate expression of vIRF-2 gene together with primary lytic cycle genes. Recombinant vIRF-2, which can form homodimers, does not bind specifically to the oligodeoxynucleotide repeats corresponding to the interferon-stimulated response element (ISRE), but it does bind to the NF-&kgr;B binding site. The fusion protein generated from vIRF-2 and the RelA (p65) activation domain stimulates transcriptional activity of HIV LTR, which contains two NF-&kgr;B sites, but does not stimulate the interferon-&bgr; (IFNB) promoter, which contains only one NF-&kgr;B site. Interaction between recombinant vIRF-2 and cellular IRFs such as IRF-1, IRF-2, and ICSBP was detected by in vitro binding assay, but no interaction between IRF-3 and vIRF-2 was found. Interaction of vIRF-2 with RelA (p65) and the carboxy-terminal part of p300 was also observed. In a transient transfection assay, vIRF-2 inhibits the IRF-1 - or IRF-3-mediated transcriptional activation of interferon-&agr; (IFNA) gene promoter in infected cells and downmodulates RelA (p65)-stimulated activity of HIV LTR.Conclusions:These results suggest that, by interacting with cellular transcription factors and cofactors, vIRF-2 may modulate the expression of the early inflammatory genes and potentially deregulate the immune system.Journal of Human Virology 1999;2:19-32 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To find cellular proteins that associate with EBNA-3 (also called EBNA-3A), one of the Epstein-Barr virus (EBV)-encoded growth transformation-associated nuclear proteins.Methods:Screening human cDNA libraries in the yeast two-hybrid system and performing an analysis of interaction in vitro as well as in cell lysates.Results:EBNA-3 binds to the epsilon subunit of the chaperonin containing T-complex protein 1 (ε-TCP-1) in the yeast two-hybrid system. The cDNA clone isolated from a human lymphocyte library was found to encode the middle and Cterminal part of ε-TCP-1. The interaction was confirmed by showing that a GST fusion protein specifically precipitated EBNA-3 from CV1 cells infected with recombinant vaccinia virus expressing EBNA-3. The interacting region was mapped to the putative apical domain of ε-TCP-1.Conclusions:This study shows that large, virus-encoded transforming proteins such as EBNA-3 may receive help for their initial folding by chaperonin complexes. The recognition of the chaperonin complex likely occurs through specific interaction with one of the subunits. We suggest that nascent EBNA-3 may recognize the TCP-1 complex by interacting with the apical region of the epsilon subunit.Journal of Human Virology 1999;2:33-37 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objectives:To study the cellular localization of human herpesvirus 8 (HHV-8) in rare cases of HHV-8 infection from Italy that are associated neither with human immunodeficiency virus (HIV) infection nor Kaposi's sarcoma (KS).Methods:The presence and distribution of HHV-8-infected cells was investigated by direct in situ polymerase chain reaction (PCR) in the lymph node tissues from 2 patients with reactive lymphadenopathies with florid follicular hyperplasia and increased vascularity and in the lung tissue from 1 patient with chronic interstitial pneumonitis.Results:HHV-8 was localized in lymphoid and monocyte-macrophage cells scattered in the interfollicular regions of both lymph nodes but not in endothelial cells. In the lung tissue, HHV-8 was found in the inflammatory cells infiltrating the interalveolar interstitium, in endothelial cells of the pulmonary vasculature, and in rare pneumocytes.Conclusions:HHV-8 can infect nonneoplastic lymph nodes of immunocompetent subjects, and the distribution of infected cells outside of the germinal centers resembles that of Epstein-Barr virus (EBV)-infected cells in the lymph nodes in the course of infectious mononucleosis. Endothelial cells and pneumocytes may be a target of HHV-8 infection out of the KS setting, at least in the presence of a chronic inflammatory process.Journal of Human Virology 1999;2:38-44 © Lippincott Williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To explore and compare the relations between proviral DNA load and CD4+lymphocyte counts in both HIV-2 monotypic and HIV dual infection.Study Design/Methods:In Dakar, Senegal, where the HIV-1 and HIV-2 epidemics overlap, serum and peripheral blood mononuclear cell (PBMC) DNA samples were collected from registered female sex workers and hospitalized patients. Sera were evaluated for reactivity to antigens of HIV-1 and HIV-2 by immunoblot; dual reactivity was confirmed with recombinant envelope peptides for HIV-1 and HIV-2. These samples were then subjected to HIV-1 and HIV-2 proviral DNA polymerase chain reaction (PCR). To evaluate the HIV-2 cellular proviral DNA loads, a quantitative competitive PCR (QC-PCR) was developed using nested primers to amplify thegagregion of HIV-2. This assay used an internal competitor generated by inserting 25 bp in the first-round PCR target sequence. T-lymphocyte subset counts were estimated by flow cytometry for both HIV-2 monotypic and dually infected persons.Results:35 HIV-2-infected and 33 dually seroreactive samples were evaluated in this study. The CD4+lymphocyte counts were similar in both groups, with mean values of 449 ± 390 cells/mm3for the HIV-2 monotypic infected persons and 476 ± 308 cells/mm3among the dually infected persons. However, the median proviral loads differed significantly, with those in the HIV-2 group ranging from 63.2 to 669.8 copies/105CD4+cells and demonstrating an inverse correlation with CD4+lymphocyte count. The HIV dually infected persons showed less variation in viral load, ranging from 9.9 to 43.3 copies/105CD4+cells. Among the HIV dually infected persons, low HIV-2 proviral load was correlated with low CD4+lymphocyte counts.Conclusions:The HIV-2 proviral loads in HIV dually infected persons were significantly lower than those in HIV-2 monotypically infected individuals (P<.0001), despite comparable CD4+lymphocyte counts. These results suggest that different HIV-2 proviral dynamics prevail in HIV dual infection.Journal of Human Virology 1999;2:45-51 © Lippincott williams & Wilkins, Inc.

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Objective:To determine CD4+T-cell count and circulating and tissue levels of HIV before and after surgery in a patient with recent-onset ulcerative colitis.Study Design/Methods:CD4 lymphocytes and circulating and tissue HIV RNA levels were measured in an HIV-infected patient with ulcerative colitis before and after proctocolectomy.Results:Approximately 3 weeks prior to surgery for ulcerative colitis that was unresponsive to corticosteroids, the patient's CD4 count was 930 cells/mm3and fell to 313 cells/mm3within 10 days; the viral burden was ˜80,000 RNA copies/mL. Tissue macrophages and lymphocytes in biopsy and resection specimens were shown to express high levels of HIV RNA by in situ hybridization. Five days postoperatively, the patient became asymptomatic and was discharged on tapering prednisone without antiretroviral agents. After surgery, the patient's CD4 count progressively rose, while viral RNA levels precipitously dropped. At 3, 6, and 15 weeks postoperatively, CD4 and viral RNA counts were 622 cells/mm3and 31,300 RNA copies/mL, 843 cells/mm3and 11,400 RNA copies/mL, and 747 cells/mm3and 1500 RNA copies/mL, respectively.Conclusions:Circulating levels of HIV and CD4+cells, as well as tissue expression of HIV, apparently can be influenced by localized inflammatory processes such as those occurring in inflammatory bowel disease.Journal of Human Virology 1999;2:52-57 © 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

ISSN:1090-9508    

出版商:OVID    

年代:1999

数据来源: OVID