302 INHIBITION OF HUMAN NATURAL KILLER (NK) CELL-MEDIATED CYTOTOXICITY IN MINIPIG CELLS BY KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS K5 PROTEIN

2008 ◽  
Vol 20 (1) ◽  
pp. 231
Author(s):  
G. S. Han ◽  
K. M. Choi ◽  
S. P. Hong ◽  
J. Y. Yoo ◽  
E. J. Kim ◽  
...  
Keyword(s):  
Natural Killer ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Cell Activation ◽  
Nk Cell ◽  
Kaposi’S Sarcoma ◽  
Xenograft Rejection ◽  
Fetal Fibroblasts ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Human natural killer (NK) cell-mediated response plays an important role in xenograft rejection. In the case of pig-to-human xenotransplantation, it has been suggested that NK cells are involved in delayed-type rejection, which is characterized by pig endothelial cell activation, direct lysis, and secretion of proinflammatory cytokines. Natural killer cell activation can be a direct barrier to the potential use of pig organs for human xenograft transplantation. Therefore, it is important to suppress NK cell activity on pig-to-human xenografts. Expression of Kaposi's sarcoma-associated herpesvirus (KSHV)-K5 molecules inhibits the cytotoxic activity of NK-activating receptor (B7-2, ICAM-1). As a consequence, K5 expression drastically inhibits NK cell-mediated cytotoxicity. In this study, we produced cell lines expressing K5 to control NK-mediated cytotoxicity in minipig cells. We transfected the K5 gene into minipig fetal fibroblasts and established 2 transgenic clonal cell lines. Presence of the K5 gene was confirmed by PCR, and expression of the gene was identified by real-time PCR and flow cytometry. In an NK cytotoxicity assay, the rate of NK-92MI-mediated cytotoxicity was significantly reduced, to 48.4 � 5.9% compared with the control (75.6 � 5.8%; P < 0.05, n = 8, paired t-testing). In conclusion, these results indicate that the expression of K5 molecules on porcine cells can efficiently control NK-mediated cytotoxicity. This strategy can be used in transgenic pig production in which porcine organs would be protected from NK-mediated rejection.

scholarly journals Lytic Replication-Defective Kaposi's Sarcoma-Associated Herpesvirus: Potential Role in Infection and Malignant Transformation

2004 ◽  
Vol 78 (20) ◽  
pp. 11108-11120 ◽  
Author(s):  
Jian-Hong Deng ◽  
Yan-Jin Zhang ◽  
Xin-Ping Wang ◽  
Shou-Jiang Gao
Keyword(s):  
Malignant Transformation ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Potential Role ◽  
Primary Effusion Lymphoma ◽  
Kaposi’S Sarcoma ◽  
Lytic Replication ◽  
Screening Methods ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Defective viruses often have pivotal roles in virus-induced diseases. Although Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL), defective KSHV has not been reported. Using differential genetic screening methods, we show that defective KSHV is present in KS tumors and PEL cell lines. To investigate the role of defective viruses in KSHV-induced pathogenesis, we isolated and characterized a lytic replication-defective KSHV, KV-1, containing an 82-kb genomic deletion of solely lytic genes. Cells harboring KV-1 escaped G0/G1 apoptosis induced by spontaneous lytic replication occurred in cells infected with regular KSHV but maintained efficient latent replication. Consequently, KV-1-infected cells had phenotypes of enhanced cell proliferation and transformation potentials. Importantly, KV-1 was packaged as infectious virions by using regular KSHV as helpers, and KV-1-like variants were detected in cultures of two of five KSHV cell lines and 1 of 18 KS tumors. These results point to a potential role for defective viruses in the regulation of KSHV infection and malignant transformation.

scholarly journals Mechanism of Angiopoietin-1 Upregulation in Kaposi's Sarcoma-Associated Herpesvirus-Infected PEL Cell Lines

2015 ◽  
Vol 89 (9) ◽  
pp. 4786-4797 ◽  
Author(s):  
Xin Zheng ◽  
Eriko Ohsaki ◽  
Keiji Ueda
Keyword(s):  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Primary Effusion Lymphoma ◽  
Regulatory Region ◽  
Leukemia Cell ◽  
Kaposi’S Sarcoma ◽  
Dependent Manner ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Angiopoietin 1

ABSTRACTAngiopoietin-1 (ANGPT-1) is a secreted glycoprotein that was first characterized as a ligand of the Tie2 receptor. In a previous study using microarray analysis, we found that the expression of ANGPT-1 was upregulated in Kaposi's sarcoma-associated herpesvirus (KSHV)-infected primary effusion lymphoma (PEL) cell lines compared with that in uninfected Burkitt and other leukemia cell lines. Other authors have also reported focal expression of ANGPT-1 mRNA in biopsy specimens of Kaposi's sarcoma (KS) tissue from patients with AIDS. Here, to confirm these findings, we examined the expression and secretion levels of ANGPT-1 in KSHV-infected PEL cell lines and address the mechanisms ofANGPT-1transcriptional regulation. We also showed that ANGPT-1 was expressed and localized in the cytoplasm and secreted into the supernatant of KSHV-infected PEL cells. Deletion studies of the regulatory region revealed that the region encompassing nucleotides −143 to −125 of theANGPT-1-regulating sequence was responsible for this upregulation. Moreover, an electrophoretic mobility shift assay and chromatin immunoprecipitation, followed by quantitative PCR, suggested that some KSHV-infected PEL cell line-specific DNA-binding factors, such as OCT-1, should be involved in the upregulation ofANGPT-1in a sequence-dependent manner.IMPORTANCEWe confirmed that ANGPT-1 was expressed in and secreted from KSHV-infected PEL cells and that the transcriptional activity ofANGPT-1was upregulated. A 19-bp fragment was identified as the region responsible forANGPT-1upregulation through binding with OCT-1 as a core factor in PEL cells. This study suggests that ANGPT-1 is overproduced in KSHV-infected PEL cells, which could affect the pathophysiology of AIDS patients with PEL.

scholarly journals Identification of a virus trans-acting regulatory element on the latent DNA replication of Kaposi's sarcoma-associated herpesvirus

2004 ◽  
Vol 85 (4) ◽  
pp. 843-855 ◽  
Author(s):  
Chunghun Lim ◽  
Taegun Seo ◽  
Jun Jung ◽  
Joonho Choe
Keyword(s):  
Dna Replication ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Regulatory Element ◽  
Kaposi’S Sarcoma ◽  
Virus Genome ◽  
Nuclear Antigen ◽  
N Terminus ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Latency-associated nuclear antigen 1 (LANA1) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays a pivotal role in the maintenance of the virus genome in latently infected cells. LANA1 links virus genomes to host chromosomes via a C-terminal DNA-binding domain which interacts with the sequences located in terminal repeats (TRs) of the virus genome and via an N-terminal chromosome-binding sequence which associates with the host chromosomes, respectively. Recent data suggest that LANA1 also actively participates in the replication of KSHV TR-containing plasmid in the transient DNA replication assay. In this report, it was found that C33A and COS-1, but not NIH/3T3, cell lines are permissive for the transient replication of KSHV TR-containing plasmid. Using several LANA1-deletion mutants, the minimum domain of LANA1 required for replication activity was also determined. In addition, the N terminus of LANA1 inhibited the transient replication systems of KSHV and Epstein–Barr virus (EBV) in transiently transfected 293 and 293T cells, but the C terminus of LANA1 specifically inhibited the transient replication system of KSHV in other cell lines. Consistent with previous reports, these data further emphasize the functional importance of the N terminus of LANA1 on replication from the KSHV latent origin of DNA replication.

scholarly journals Epstein-Barr Virus Recombinants from BC-1 and BC-2 Can Immortalize Human Primary B Lymphocytes with Different Levels of Efficiency and in the Absence of Coinfection by Kaposi's Sarcoma-Associated Herpesvirus

2000 ◽  
Vol 74 (2) ◽  
pp. 735-743 ◽  
Author(s):  
Andrew J. Aguirre ◽  
Erle S. Robertson
Keyword(s):  
B Lymphocytes ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Epstein Barr Virus ◽  
Kaposi’S Sarcoma ◽  
Barr Virus ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Epstein Barr ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Different Levels

ABSTRACT Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are human gammaherpesviruses associated with numerous malignancies. Primary effusion lymphoma or body cavity-based lymphoma is a distinct clinicopathological entity that, in the majority of cases, manifests coinfection with KSHV and EBV. In previous analyses, we have characterized the EBV in the BC-1 and BC-2 cell lines as potential intertypic recombinants of the EBV types 1 and 2. In order to examine the infectious and transforming capacities of KSHV and the intertypic EBV recombinants from the BC-1 and BC-2 cell lines, viral replication was induced in these cell lines and fresh human primary B lymphocytes were infected with progeny virus. The transformed clones were analyzed by PCR and Western blotting. All analyzed clones were infected with the intertypic progeny EBV but had no detectable signal for progeny KSHV. Additionally, primary B lymphocytes incubated with viral supernatant containing KSHV alone showed an unsustained initial proliferation, but prolonged growth or immortalization of these cells in vitro was not observed. We also show that the EBV recombinants from BC-1 were less efficient than the EBV recombinants from BC-2 in the ability to maintain the transformed phenotype of the infected human B lymphocytes. From these findings, we conclude that the BC-1 and BC-2 intertypic EBV recombinants can immortalize human primary B lymphocytes, albeit at different levels of efficiency. However, the KSHV induced from BC-1 and BC-2 alone cannot transform primary B cells, nor can it coinfect EBV-positive B lymphocytes under our experimental conditions with B lymphocytes from EBV-seropositive individuals. These results are distinct from those in one previous report and suggest a possible requirement for other factors to establish coinfection with both viral agents.

scholarly journals Role of the Kaposi's Sarcoma-Associated Herpesvirus K15 SH3 Binding Site in Inflammatory Signaling and B-Cell Activation

2010 ◽  
Vol 84 (16) ◽  
pp. 8231-8240 ◽  
Author(s):  
Marcel Pietrek ◽  
Melanie M. Brinkmann ◽  
Ilona Glowacka ◽  
Anette Enlund ◽  
Anika Hävemeier ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
B Cell ◽  
Binding Site ◽  
Kaposi's Sarcoma ◽  
Cell Activation ◽  
Kaposi’S Sarcoma ◽  
Binding Motif ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT The Kaposi's sarcoma-associated herpesvirus (KSHV) contains several open reading frames (ORFs) that encode proteins capable of initiating and modulating cellular signaling pathways. Among them is ORF K15, encoding a 12-transmembrane-spanning protein with a cytoplasmic C-terminal domain. Through conserved binding motifs, such as Src homology 2 (SH2) and SH3 binding sites, K15 interacts with cellular proteins, activates the NF-κB, MEK/Erk, and Jun N-terminal protein kinase (JNK) pathways, and induces the expression of several inflammatory and angiogenic genes. In this study, we investigated the role of an SH3 domain binding site centered on a PPLP motif in K15. We screened libraries of cellular SH3 domains to identify signaling molecules interacting with the KSHV PPLP motif. We found its affinities for two Src kinase family members, Lyn and Hck, to exceed those of other viral proteins. While the SH2 binding motif YEEV is essential for the inflammatory response induced by KSHV K15, recruitment of Lyn and Hck to the K15 PPLP motif seems to be dispensable for this inflammatory response. However, the PPLP motif is essential for the decrease in B-cell receptor-mediated signaling induced by K15, as measured by calcium mobilization assays.

scholarly journals Host Range of Kaposi's Sarcoma-Associated Herpesvirus in Cultured Cells

2003 ◽  
Vol 77 (11) ◽  
pp. 6474-6481 ◽  
Author(s):  
Jill T. Bechtel ◽  
Yuying Liang ◽  
Joshua Hvidding ◽  
Don Ganem
Keyword(s):  
Host Range ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Latent Infection ◽  
Kaposi’S Sarcoma ◽  
Lytic Replication ◽  
Serial Transfer ◽  
Latently Infected ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Difficulties in efficiently propagating Kaposi's sarcoma-associated herpesvirus (KSHV) in culture have generated the impression that the virus displays a narrow host range. Here we show that, contrary to expectation, KSHV can establish latent infection in many adherent cell lines, including human and nonhuman cells of epithelial, endothelial, and mesenchymal origin. (Paradoxically, the only lines in which we have not observed successful latent infection are cultured lymphoma cell lines.) In most latently infected lines, spontaneous lytic replication is rare and (with only two exceptions) is not efficiently induced by phorbol ester treatment—a result that explains the failure of most earlier studies to observe efficient serial transfer of infection. However, ectopic expression of the KSHV lytic switch protein RTA from an adenoviral vector leads to the prompt induction of lytic replication in all latently infected lines, with the production of infectious KSHV virions. These results indicate (i) that the host cell receptor(s) and entry machinery for KSHV are widely distributed on cultured adherent cells, (ii) that latency is the default pathway of infection, and (iii) that blocks to lytic induction are frequent and largely reside at or upstream of the expression of KSHV RTA.

scholarly journals Efficient Infection by a Recombinant Kaposi's Sarcoma-Associated Herpesvirus Cloned in a Bacterial Artificial Chromosome: Application for Genetic Analysis

2002 ◽  
Vol 76 (12) ◽  
pp. 6185-6196 ◽  
Author(s):  
Fu-Chun Zhou ◽  
Yan-Jin Zhang ◽  
Jian-Hong Deng ◽  
Xin-Ping Wang ◽  
Hong-Yi Pan ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Artificial Chromosome ◽  
Lytic Replication ◽  
Kshv Infection ◽  
293 Cells ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma and several other malignancies. The lack of an efficient infection system has impeded the understanding of KSHV-related pathogenesis. A genetic approach was used to isolate infectious KSHV. Recombinant bacteria artificial chromosome (BAC) KSHV containing hygromycin resistance and green fluorescent protein (GFP) markers was generated by homologous recombination in KSHV-infected BCBL-1 cells. Recombinant KSHV genomes from cell clones that were resistant to hygromycin, expressed GFP, and produced infectious virions after induction with tetradecanoyl phorbol acetate (TPA) were rescued in Escherichia coli and reconstituted in 293 cells. Several 293 cell lines resulting from infection with recombinant virions induced from a full-length recombinant KSHV genome, named BAC36, were obtained. BAC36 virions established stable latent infection in 293 cells, harboring 1 to 2 copies of viral genome per cell and expressing viral latent proteins, with ≈0.5% of cells undergoing spontaneous lytic replication, which is reminiscent of KSHV infection in Kaposi's sarcoma tumors. TPA treatment induced BAC36-infected 293 cell lines into productive lytic replication, expressing lytic proteins and producing virions that efficiently infected normal 293 cells with a ≈50% primary infection rate. BAC36 virions were also infectious to HeLa and E6E7-immortalized human endothelial cells. Since BAC36 can be efficiently shuttled between bacteria and mammalian cells, it is useful for KSHV genetic analysis. The feasibility of the system was illustrated through the generation of a KSHV mutant with the vIRF gene deleted. This cellular model is useful for the investigation of KSHV infection and pathogenesis.

scholarly journals Patterns of Gene Expression and a Transactivation Function Exhibited by the vGCR (ORF74) Chemokine Receptor Protein of Kaposi's Sarcoma-Associated Herpesvirus

2002 ◽  
Vol 76 (7) ◽  
pp. 3421-3439 ◽  
Author(s):  
Chuang-Jiun Chiou ◽  
Lynn J. Poole ◽  
Peter S. Kim ◽  
Dolores M. Ciufo ◽  
Jennifer S. Cannon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Line ◽  
Cell Lines ◽  
Reporter Gene ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Lytic Cycle ◽  
In Vitro Translation ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT The ORF74 or vGCR gene encoded by Kaposi's sarcoma-associated herpesvirus (KSHV; also called human herpesvirus 8) has properties of a ligand-independent membrane receptor signaling protein with angiogenic properties that is predicted to play a key role in the biology of the virus. We have examined the expression of vGCR mRNA and protein in primary effusion lymphoma (PEL) cell lines, PEL and multicentric Castleman's disease (MCD) tumors, Kaposi's sarcoma lesions and infected endothelial cell cultures. The vGCR gene proved to be expressed in PEL cell lines as a large spliced bicistronic mRNA of 3.2 kb that also encompasses the upstream vOX2 (K14) gene. This mRNA species was induced strongly by phorbol ester (TPA) and sodium butyrate treatment in the BCBL-1 cell line, but only weakly in the HBL6 cell line, and was classified as a relatively late and low-abundance delayed early class lytic cycle gene product. A complex bipartite upstream lytic cycle promoter for this mRNA was nestled within the intron of the 5′-overlapping but oppositely oriented latent-state transcription unit for LANA1/vCYC-D/vFLIP and responded strongly to both TPA induction and cotransfection with the KSHV RNA transactivator protein (RTA or ORF50) in transient reporter gene assays. A vGCR protein product of 45 kDa that readily dimerized was detected by Western blotting and in vitro translation and was localized in a cytoplasmic and membrane pattern in DNA-transfected Vero and 293T cells or adenovirus vGCR-transduced dermal microvascular endothelial cells (DMVEC) as detected by indirect immunofluorescence assay (IFA) and immunohistochemistry with a specific rabbit anti-vGCR antibody. Similarly, a subfraction of KSHV-positive cultured PEL cells and of KSHV (JSC-1) persistently infected DMVEC cells displayed cytoplasmic vGCR protein expression, but only after TPA or spontaneous lytic cycle induction, respectively. The vGCR protein was also detectable by immunohistochemical staining in a small fraction (0.5 to 3%) of the cells in PEL and MCD tumor and nodular Kaposi's sarcoma lesion specimens that were apparently undergoing lytic cycle expression. These properties are difficult to reconcile with the vGCR protein's playing a direct role in spindle cell proliferation, transformation, or latency, but could be compatible with proposed contributions to angiogenesis via downstream paracrine effects. The ability of vGCR to transactivate expression of both several KSHV promoter-driven luciferase (LUC) reporter genes and an NFκB motif containing the chloramphenicol acetyltransferase (CAT) reporter gene may also suggest an unexpected regulatory role in viral gene expression.

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