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Kominsky DJ, Bickel RJ, Tyler KL. Reovirus-induced apoptosis requires both death receptor- and mitochondrial-mediated caspase-dependent pathways of cell death. Cell Death Differ 2002; 9:926-33. [PMID: 12181743 DOI: 10.1038/sj.cdd.4401045] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2001] [Revised: 01/14/2002] [Accepted: 02/06/2002] [Indexed: 11/08/2022] Open
Abstract
Apoptosis plays an important role in the pathogenesis of many viral infections. Despite this fact, the apoptotic pathways triggered during viral infections are incompletely understood. We now provide the first detailed characterization of the pattern of caspase activation following infection with a cytoplasmically replicating RNA virus. Reovirus infection of HEK293 cells results in the activation of caspase-8 followed by cleavage of the pro-apoptotic protein Bid. This initiates the activation of the mitochondrial apoptotic pathway leading to release of cytochrome c and activation of caspase-9. Combined activation of death receptor and mitochondrial pathways results in downstream activation of effector caspases including caspase-3 and caspase-7 and cleavage of cellular substrates including PARP. Apoptosis is initiated by death receptor pathways but requires mitochondrial amplification producing a biphasic pattern of caspase-8, Bid, and caspase-3 activation.
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Affiliation(s)
- D J Kominsky
- Department of Neurology, University of Colorado Health Science Center, Denver, Colorado 80262, USA
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52
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Haglund K, Leiner I, Kerksiek K, Buonocore L, Pamer E, Rose JK. Robust recall and long-term memory T-cell responses induced by prime-boost regimens with heterologous live viral vectors expressing human immunodeficiency virus type 1 Gag and Env proteins. J Virol 2002; 76:7506-17. [PMID: 12097563 PMCID: PMC136360 DOI: 10.1128/jvi.76.15.7506-7517.2002] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We investigated long-term memory and recall cellular immune responses to human immunodeficiency virus type 1 (HIV-1) Env and Gag proteins elicited by recombinant vesicular stomatitis viruses (VSVs) expressing Env and Gag. More than 7 months after a single vaccination with VSV-Env, approximately 6% of CD8(+) splenocytes stained with major histocompatibility complex class I tetramers containing the Env p18-I10 immunodominant peptide and showed a memory phenotype (CD44(Hi)). The level of tetramer-positive cells in memory was about 14% of the peak primary response. Recall responses elicited in these mice 5 days after boosting with a heterologous recombinant vaccinia virus expressing HIV-1 Env showed that 40 to 45% of CD8(+) splenocytes were tetramer positive and activated (CD62L(Lo)), and these cells produced gamma interferon after stimulation with Env peptide, indicating that they were functional. Five months after the boost, the long-term memory cell population (tetramer positive, CD44(Hi)) constituted 30% of the CD8(+) splenocytes. Recall responses to HIV-1 Gag were examined in mice primed with VSV recombinants expressing HIV-1 Gag protein and boosted with a vaccinia virus recombinant expressing Gag. Using this protocol, we found that approximately 40% of CD8(+) splenocytes were activated (CD62L(Lo)) and specific for a Gag immunodominant peptide (tetramer positive). The high-level Gag recall response elicited by the vaccinia virus-Gag was greater than that obtained by boosting with a VSV-Gag vector with a different VSV glycoprotein. The corresponding levels of CD44(Hi) memory cells were also higher long after boosting with vaccinia virus-Gag than after boosting with a glycoprotein exchange VSV-Gag. Our results show that VSV vectors elicit high-level memory CTL responses and that these can be amplified as much as six- to sevenfold using a heterologous boosting vector.
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Affiliation(s)
- Karl Haglund
- Department of Pathology, Program in Microbiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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53
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Labrada L, Bodelón G, Viñuela J, Benavente J. Avian reoviruses cause apoptosis in cultured cells: viral uncoating, but not viral gene expression, is required for apoptosis induction. J Virol 2002; 76:7932-41. [PMID: 12133997 PMCID: PMC155131 DOI: 10.1128/jvi.76.16.7932-7941.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2002] [Accepted: 05/10/2002] [Indexed: 12/20/2022] Open
Abstract
The cytopathic effect evidenced by cells infected with avian reovirus S1133 suggests that this virus may induce apoptosis in primary cultures of chicken embryo fibroblasts. In this report we present evidence that avian reovirus infection of cultured cells causes activation of the intracellular apoptotic program and that this activation takes place during an early stage of the viral life cycle. The ability of avian reoviruses to induce apoptosis is not restricted to a particular virus strain or to a specific cell type, since different avian reovirus isolates were able to induce apoptosis in several avian and mammalian cell lines. Apoptosis was also provoked in ribavirin-treated avian reovirus-infected cells and in cells infected with UV-irradiated reovirions, indicating that viral mRNA synthesis and subsequent steps in viral replication are not needed for apoptosis induction in avian reovirus-infected cells and that the number of inoculated virus particles, not their infectivity, is the critical factor for apoptosis induction by avian reovirus. Our finding that apoptosis is no longer induced when intracellular viral uncoating is blocked indicates that intraendosomal virion disassembly is required for apoptosis induction and that attachment and uptake of parental reovirions are not sufficient to cause apoptosis. Taken together, our results suggest that apoptosis is triggered from within the infected cell by viral products generated after intraendosomal uncoating of parental reovirions.
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Affiliation(s)
- Lucía Labrada
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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54
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Affiliation(s)
- J M McNally
- Department of Pathology, Program in Immunology and Virology, University of Massachusetts Medical Center, Worcester, MA 01655, USA
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55
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Zhang Y, Wang Y, Gilmore X, Xu K, Chen M, Tebebi P, Mbawuike IN. Apoptosis and reduced influenza A virus specific CD8+ T cells in aging mice. Cell Death Differ 2002; 9:651-60. [PMID: 12032674 DOI: 10.1038/sj.cdd.4401011] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2001] [Revised: 11/20/2001] [Accepted: 12/21/2001] [Indexed: 11/09/2022] Open
Abstract
Some studies have reported increased apoptosis in CD8(+) T cells from aged mice. We previously demonstrated diminished virus-specific CD8(+) cytotoxic T lymphocyte (CTL) activity in aged mice in comparison to young mice. The present study investigated the role of apoptosis in age-related influenza virus-specific CD8(+) CTL deficiency. Splenocytes from influenza-primed aged and young mice were stimulated in vitro with virus. The CD8(+) T cell/total lymphocyte ratios correlated with CTL activity and were significantly decreased and increased in aged and young mice, respectively. Fas, FasL, TNF-alpha and TNFR-p55 expression, measured by flow cytometry, ELISA and/or RT-PCR, were significantly elevated in aged mice. Apoptotic CD8(+) T cells (Annexin V binding) were also elevated in aged mice. IL-12 treatment increased CD8(+) CTL activity and IFN-gamma production but did not affect apoptosis. Thus, apoptosis may contribute to reduced influenza virus-specific CD8(+) T cell frequency, CTL deficiency and increased influenza disease in aging.
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Affiliation(s)
- Y Zhang
- Influenza Research Center, Respiratory Pathogens Research Unit, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, TX 77030, USA
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56
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Gadaleta P, Vacotto M, Coulombié F. Vesicular stomatitis virus induces apoptosis at early stages in the viral cycle and does not depend on virus replication. Virus Res 2002; 86:87-92. [PMID: 12076832 DOI: 10.1016/s0168-1702(02)00049-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We detected apoptosis induction in the vesicular stomatitis virus (VSV) infected mammalian cell lines Vero-76, Cos-7, and BHK-21. Cell lines were analyzed by chromosomal DNA fragmentation and nuclear morphology. In order to determine the step in the viral cycle at which apoptosis of infected cells is triggered, chemical and physical agents were used to block viral infection at different times and then the apoptotic response of infected cells was examined. The treatment of Vero-76 infected cells with a lysosomotrophic agent, such as NH4Cl, was shown to abrogate virus apoptosis induction. On the other hand, VSV-induced apoptosis was not blocked by the presence of cycloheximide, suggesting that the de novo viral protein synthesis is not required for this process. UV-inactivated viruses were also capable of inducing apoptosis in Vero-76 cells, indicating that the activation of a programmed cell death process by VSV does not require viral replication. We conclude from these findings that VSV induces apoptosis at early stages of infection.
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Affiliation(s)
- Patricia Gadaleta
- Department of Biological Chemistry, Laboratory of Virology, Faculty of Science, University of Buenos Aires, Ciudad Universitaria, Pabellón II, Piso 4, Buenos Aires, Argentina.
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57
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Schwartz T, Fu L, Lavi E. Differential induction of apoptosis in demyelinating and nondemyelinating infection by mouse hepatitis virus. J Neurovirol 2002; 8:392-9. [PMID: 12402165 PMCID: PMC7094974 DOI: 10.1080/13550280260422695] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The role of apoptosis in mouse hepatitis virus (MHV) infection is still controversial. To better assess the role of apoptosis in MHV infection, we used three different biologic phenotypes of MHV to examine their differential effect on the induction of apoptosis. MHV-A59 produces acute hepatitis, meningoencephalitis, and chronic demyelination. MHV-2 causes only acute hepatitis and meningitis, whereas Penn98-1 produces acute hepatitis and meningoencephalitis without demyelination. We detected TdT-mediated dUTP nick-end labeling (TUNEL) staining in the livers and meninges of MHV-A59-, MHV-2-, and Penn98-1-infected mice. TUNEL staining in brain parenchyma was only detected in MHV-A59- and Penn98-1-infected mice. We detected apoptosis by electronmicroscopy in olfactory neurons during acute infection with MHV-A59. The kinetics and distribution of TUNEL staining correlated with the pathologic damage and colocalized with viral antigen in some cells. At 1 month, TUNEL staining was found exclusively in areas of demyelination in the spinal cord of MHV-A59-infected mice; however, it was not found in nondemyelinated mice infected with MHV-2 or Penn98-1, or in mock-infected mice. TUNEL-positive cells were identified as macrophage/microglial cells, some astrocytes, and some oligodendrocytes, by colabeling with cell-specific markers. The presence of TUNEL staining in oligodendrocytes suggests that apoptosis may play an important role in MHV-induced demyelination.
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Affiliation(s)
- Talya Schwartz
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, 613 Stellar-Chance Laboratories, University of Pennsylvania, School of Medicine, 422 Curie Boulevard, 19104-6100 Philadelphia, PA USA
| | - Li Fu
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, 613 Stellar-Chance Laboratories, University of Pennsylvania, School of Medicine, 422 Curie Boulevard, 19104-6100 Philadelphia, PA USA
| | - Ehud Lavi
- Division of Neuropathology, Department of Pathology and Laboratory Medicine, 613 Stellar-Chance Laboratories, University of Pennsylvania, School of Medicine, 422 Curie Boulevard, 19104-6100 Philadelphia, PA USA
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58
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Takikita S, Takano T, Narita T, Takikita M, Ohno M, Shimada M. Neuronal apoptosis mediated by IL-1 beta expression in viral encephalitis caused by a neuroadapted strain of the mumps virus (Kilham Strain) in hamsters. Exp Neurol 2001; 172:47-59. [PMID: 11681839 DOI: 10.1006/exnr.2001.7773] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The neuroadapted Kilham strain of the mumps virus produces lethal encephalitis in newborn hamsters after intracerebral inoculation. The pathogenesis of this encephalitis is not fully understood, but recently, apoptosis and associated cytokine production have been recognized to be major pathologic mechanisms by which viruses cause injury to neuronal host cells. To analyze the main factors producing brain injury in this viral encephalitis, the following questions were investigated: (1) does the virus induce neuronal apoptosis and (2) does expression of cytokines regulate the induction of neuronal apoptosis? Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) was used as a marker of neuronal apoptosis and TUNEL-positive neurons were widespread in the infected cerebral cortex. DNA fragmentation yielding DNA ladders characteristic of apoptosis was also observed in infected hamster brain tissue. Apoptotic cells in infected brains were observed after the appearance of inflammatory changes. Overexpression of IL-1 beta, but not TNF-alpha or Fas-L, was clearly detected in infected brains, as determined by Western blot and RT-PCR. Immunohistochemistry revealed a striking correlation between IL-1 beta expression and neuronal apoptosis. Injection of recombinant IL-1 beta into normal hamster brain resulted in neuronal apoptosis in cerebral cortex. On the other hand, neutralizing IL-1 beta antibodies decreased the number of cells undergoing apoptosis in infected hamster brains and subsequent death. We conclude that the fatal encephalitis induced by the Kilham strain of the mumps virus is mediated by immunopathological processes and that overexpression of IL-1 beta, which mediates the induction of neuronal apoptosis, may play a major role in these processes.
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Affiliation(s)
- S Takikita
- Department of Pediatrics, Shiga University of Medical Science, Tsukinowa, Seta, Otsu, Shiga 520-2192, Japan.
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59
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Schultz-Cherry S, Dybdahl-Sissoko N, Neumann G, Kawaoka Y, Hinshaw VS. Influenza virus ns1 protein induces apoptosis in cultured cells. J Virol 2001; 75:7875-81. [PMID: 11483732 PMCID: PMC115031 DOI: 10.1128/jvi.75.17.7875-7881.2001] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The importance of influenza viruses as worldwide pathogens in humans, domestic animals, and poultry is well recognized. Discerning how influenza viruses interact with the host at a cellular level is crucial for a better understanding of viral pathogenesis. Influenza viruses induce apoptosis through mechanisms involving the interplay of cellular and viral factors that may depend on the cell type. However, it is unclear which viral genes induce apoptosis. In these studies, we show that the expression of the nonstructural (NS) gene of influenza A virus is sufficient to induce apoptosis in MDCK and HeLa cells. Further studies showed that the multimerization domain of the NS1 protein but not the effector domain is required for apoptosis. However, this mutation is not sufficient to inhibit apoptosis using whole virus.
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Affiliation(s)
- S Schultz-Cherry
- Southeast Poultry Research Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Athens, Georgia 30605, USA.
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60
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Liu C, Xu HY, Liu DX. Induction of caspase-dependent apoptosis in cultured cells by the avian coronavirus infectious bronchitis virus. J Virol 2001; 75:6402-9. [PMID: 11413307 PMCID: PMC114363 DOI: 10.1128/jvi.75.14.6402-6409.2001] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Avian coronavirus infectious bronchitis virus (IBV) is the causative agent of chicken infectious bronchitis, an acute, highly contagious viral respiratory disease. Replication of IBV in Vero cells causes extensive cytopathic effects (CPE), leading to destruction of the entire monolayer and the death of infected cells. In this study, we investigated the cell death processes during acute IBV infection and the underlying mechanisms. The results show that both necrosis and apoptosis may contribute to the death of infected cells in lytic IBV infection. Caspase-dependent apoptosis, as characterized by chromosomal condensation, DNA fragmentation, caspase-3 activation, and poly(ADP-ribose) polymerase degradation, was detected in IBV-infected Vero cells. Addition of the general caspase inhibitor z-VAD-FMK to the culture media showed inhibition of the hallmarks of apoptosis and increase of the release of virus to the culture media at 16 h postinfection. However, neither the necrotic process nor the productive replication of IBV in Vero cells was severely affected by the inhibition of apoptosis. Screening of 11 IBV-encoded proteins suggested that a 58-kDa mature cleavage product could induce apoptotic changes in cells transiently expressing the protein. This study adds one more example to the growing list of animal viruses that induce apoptosis during their replication cycles.
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Affiliation(s)
- C Liu
- Institute of Molecular Agrobiology, 1 Research Link, The National University of Singapore, Singapore 117406, Singapore.
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61
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Jelachich ML, Lipton HL. Theiler's murine encephalomyelitis virus induces apoptosis in gamma interferon-activated M1 differentiated myelomonocytic cells through a mechanism involving tumor necrosis factor alpha (TNF-alpha) and TNF-alpha-related apoptosis-inducing ligand. J Virol 2001; 75:5930-8. [PMID: 11390594 PMCID: PMC114308 DOI: 10.1128/jvi.75.13.5930-5938.2001] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Infection of susceptible mice with the low-neurovirulence Theiler's murine encephalomyelitis virus strain BeAn results in an inflammatory demyelinating disease similar to multiple sclerosis. While the majority of virus antigen is detected in central nervous system macrophages (Mphis), few infiltrating Mphis are infected. We used the myelomonocytic precursor M1 cell line to study BeAn virus-Mphi interactions in vitro to elucidate mechanisms for restricted virus expression. We have shown that restricted BeAn infection of M1 cells differentiated in vitro (M1-D) results in apoptosis. In this study, BeAn infection of gamma interferon (IFN-gamma)-activated M1-D cells also resulted in apoptosis but with no evidence of virus replication or protein expression. RNase protection assays of M1-D cellular RNA revealed up-regulation of Fas and the p55 chain of the tumor necrosis factor alpha (TNF-alpha) receptor transcripts with IFN-gamma activation. BeAn infection of activated cells resulted in increased caspase 8 mRNA transcripts and the appearance of TNF-alpha-related apoptosis-inducing ligand (TRAIL) 4 h postinfection. Both unactivated and activated M1-D cells expressed TRAIL receptors (R1 and R2), but only activated cells were killed by soluble TRAIL. Activated cells were also susceptible to soluble FasL- and TNF-alpha-induced apoptosis. The data suggest that IFN-gamma-activated M1-D cell death receptors become susceptible to their ligands and that the cells respond to BeAn virus infection by producing the ligands TNF-alpha and TRAIL to kill the susceptible cells. Unactivated cells are not susceptible to FasL or TRAIL and require virus replication to initiate apoptosis. Therefore, two mechanisms of apoptosis induction can be triggered by BeAn infection: an intrinsic pathway requiring virus replication and an extrinsic pathway signaling through the death receptors.
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Affiliation(s)
- M L Jelachich
- Evanston Northwestern Healthcare Research Institute and Northwestern University, 2650 Ridge Ave., Evanston, IL 60201, USA.
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62
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Abstract
The mechanism of cell death induced by West Nile virus (WNV), a causative agent of human febrile syndrome and encephalitis, was investigated. WNV-infected K562 and Neuro-2a cells manifested the typical features of apoptosis, including cell shrinkage, chromatin condensation and subdiploid DNA content by flow cytometry. DNA fragmentation into nucleosomal size and changes in outer cell membrane phospholipid composition were also observed in K562 cells. UV-inactivated virus failed to induce the above-mentioned characteristics, suggesting that viral replication may be required for the induction of apoptosis by WNV. Additionally, signals involved in WNV-induced apoptosis are associated with the up-regulation of bax gene expression.
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Affiliation(s)
- M C Parquet
- Department of Virology, Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
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63
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Lee YI, Kang-Park S, Do SI, Lee YI. The hepatitis B virus-X protein activates a phosphatidylinositol 3-kinase-dependent survival signaling cascade. J Biol Chem 2001; 276:16969-77. [PMID: 11278872 DOI: 10.1074/jbc.m011263200] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The hepatitis B virus-X (HBx) protein is known as a multifunctional protein that not only coactivates transcription of viral and cellular genes but coordinates the balance between proliferation and programmed cell death, by inducing or blocking apoptosis. In this study the role of the HBx protein in activation of phosphatidylinositol 3-kinase (PI3K) was investigated as a possible cause of anti-apoptosis in liver cells. HBx relieved serum deprivation-induced and pro-apoptic stimuli-induced apoptosis in Chang liver (CHL) cells. Treatment with 1-d-3-deoxy-3-fluoro-myo-inositol, an antagonist to PI3K, which blocks the formation of 3'-phosphorylated phosphatidyl inositol in CHL cells transformed by HBx (CHL-X) but not normal Chang liver (CHL) cells, showed a marked loss of viability with evidence of apoptosis. Similarly, treatment with wortmannin, an inhibitor of PI3K, stimulated apoptosis in HBx-transformed CHL cells but not in normal cells, confirming that HBx blocks apoptosis through the PI3K pathway. The serine 47 threonine kinase, Akt, one of the downstream effectors of PI3K-dependent survival signaling was 2-fold higher in HBx-transformed CHL (CHL-X) cells than CHL cells. Phosphorylation of Akt at serine 473 and Bad at serine 136 were induced by HBx, which were specifically blocked by wortmannin and dominant negative mutants of Akt and Bad, respectively. We also demonstrated that HBx inhibits caspase 3 activity and HBx down-regulation of caspase 3 activity was blocked by the PI3K inhibitor. Regions required for PI3K phosphorylation on the HBx protein overlap with the known transactivation domains. HBx blocks apoptosis induced by serum withdrawal in CHL cells in a p53-independent manner. The results indicate that, unlike other DNA tumor viruses that block apoptosis by inactivating p53, the hepatitis B virus achieves protection from apoptotic death through a HBx-PI3K-Akt-Bad pathway and by inactivating caspase 3 activity that is at least partially p53-independent in liver cells. Moreover, these data suggest that modulation of the PI3K activity may represent a potential therapeutic strategy to counteract the occurrence of apoptosis in human hepatocellular carcinoma.
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Affiliation(s)
- Y I Lee
- Liver Cell Signal Transduction Research Unit, Animal Cell and Medical Glycobiology Research Unit, Bioscience Research Division, Korea Research Institute of Bioscience and Biotechnology, P. O. Box 115, Yusong, Taejon 305-600, Korea
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64
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Opferman JT, Ober BT, Narayanan R, Ashton-Rickardt PG. Suicide induced by cytolytic activity controls the differentiation of memory CD8(+) T lymphocytes. Int Immunol 2001; 13:411-9. [PMID: 11282980 DOI: 10.1093/intimm/13.4.411] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cytotoxic T lymphocytes (CTL) confer protection against intracellular pathogens, yet the mechanism by which some escape activation induced cell death (AICD) and give rise to long-lived memory cells is unclear. We studied the differentiation of transgenic TCR CD8(+) cells into CTL and memory cells using a novel system that allowed us to control cytolytic activity. The perforin/granzyme granules used to lyse targets induced the apoptosis of CTL in a fratricide-independent manner. After adoptive transfer to antigen-free mice, the ability of CTL to give generate memory cells was determined. We found that the extent of cytolysis by a common pool of CTL controlled the differentiation into memory cells, which were only generated under conditions of minimal cytolytic activity. Thus, the differentiation of naive CD8(+) cells into memory cells may not depend on the presence on a subset of committed CTL precursors, but rather is controlled by the extent of granule-mediated cytolysis.
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Affiliation(s)
- J T Opferman
- Committee on Immunology, Department of Pathology and Ben May Institute for Cancer Research, University of Chicago, Chicago, IL 60637, USA
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65
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Abstract
Cell death by apoptosis is an efficient mechanism of eliminating unwanted or aberrant cells. Triggering of Fas, a member of the tumor necrosis factor (TNF) receptor superfamily, by anti-Fas antibodies or by the Fas ligand (FasL), has been shown to cause cell death by apoptosis. A recent study from our laboratory has demonstrated that Fas crosslinking leads to the dephosphorylation of the tumor suppressor retinoblastoma protein (Rb) and that this dephosphorylation is inhibited by calyculin A, a serine/threonine phosphatase inhibitor. In this investigation, we compared the effect of Fas crosslinking by CH11, an anti-Fas mAb, with two cyclin-dependent kinase (CDK) inhibitors, a peptide that specifically inhibits CDK2 (cdk2 inh) and roscovitine, which inhibits CDK2, CDC2, and CDK5. We illustrate that roscovitine induced DNA fragmentation, whereas cdk2 inh did not. In contrast to Fas-induced apoptosis, roscovitine-induced apoptosis was resistant to calyculin A. Both cdk2 inh and roscovitine induced cleavage of poly (ADP-ribose) polymerase (PARP) within 2 h. Roscovitine, however, led to the degradation of Rb, whereas cdk2 inh did not. Furthermore, both CH11 and roscovitine caused cell cycle arrest in S phase. In contrast, cdk2 inh did not have any effect on Jurkat cell cycle progression. Taken together, our results strongly suggest that the maintenance of Rb in its hyperphosphorylated form during S phase may be necessary for cell survival and that Rb dephosphorylation during S phase may constitute a crucial step in Fas-induced apoptosis.
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Affiliation(s)
- M N'cho
- Department of Microbiology/Immunology, Indianapolis, IN 46202-5200, USA
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66
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Mondal B, Sreenivasa BP, Dhar P, Singh RP, Bandyopadhyay SK. Apoptosis induced by peste des petits ruminants virus in goat peripheral blood mononuclear cells. Virus Res 2001; 73:113-9. [PMID: 11172915 DOI: 10.1016/s0168-1702(00)00214-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The ability of peste des petits ruminants virus (PPRV) to induce apoptosis in goat peripheral blood mononuclear cell (PBMC) culture was investigated. Goat PBMC were infected with PPRV and the infectivity was confirmed by cytopathic effect, demonstration of presence of infectious viral progeny and expression of viral antigens in the lymphocytes, cultured in vitro. Infected PBMC showed morphological features of apoptosis. DNA extracted from PPRV-infected cells displayed laddering pattern in agarose gel electrophoresis. Infected cells also showed significantly higher apoptotic indices measured by bisbenzimide staining than control cells. Electronmicrographs of PPRV-infected PBMC revealed features typical of apoptosis such as peripheral condensation of chromatin, blebbing of plasma membrane, fragmentation of nucleus and cell leading to formation of apoptotic bodies. Our results suggest that PPRV can induce apoptosis, in vitro, in goat lymphocytes.
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Affiliation(s)
- B Mondal
- Division of Virology, Indian Veterinary Research Institute, UP 263138, Mukteswar, India.
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67
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Abstract
Equine arteritis virus (EAV) is the etiological agent of equine viral arteritis, a contagious viral disease of equids. EAV is the prototype virus of the arteriviruses, a group of small enveloped viruses with positive single-stranded RNA genomes. Because apoptosis or programmed cell death is believed to play an important role in the biogenesis of several cytopathogenic viruses, we examined whether EAV was able to induce cell apoptosis in vitro. To do this, Vero cells were infected with EAV at a multiplicity of infection of 0.1 tissue culture infectious dose (TCID50) per cell, and analyzed at various time intervals for the appearance of apoptotic signs. Fragmentation of chromosomal DNA into nucleosomal oligomers and caspase activation were observed in the infected cells at the time (e.g. 24h postinfection) where a noticeable cytopathic effect was observed. The kinetics of the DNA fragmentation correlated with that of the production of progeny virus, so that viral multiplication was not interrupted by the apoptotic cell damage. All these data provide evidence that EAV is able to induce apoptotic cell death in vitro.
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Affiliation(s)
- D Archambault
- University of Québec at Montreal, Department of Biological Sciences, Succursale Centre-ville, Canada.
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68
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Varga SM, Selin LK, Welsh RM. Independent regulation of lymphocytic choriomeningitis virus-specific T cell memory pools: relative stability of CD4 memory under conditions of CD8 memory T cell loss. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:1554-61. [PMID: 11160196 DOI: 10.4049/jimmunol.166.3.1554] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection of mice with a series of heterologous viruses causes a reduction of memory CD8(+) T cells specific to viruses from earlier infections, but the fate of the virus-specific memory CD4(+) T cell pool following multiple virus infections has been unknown. We have previously reported that the virus-specific CD4(+) Th precursor (Thp) frequency remains stable into long-term immunity following lymphocytic choriomeningitis virus (LCMV) infection. In this study, we questioned whether heterologous virus infections or injection with soluble protein CD4 Ags would impact this stable LCMV-specific CD4(+) Thp memory pool. Limiting dilution analyses for IL-2-producing cells and intracellular cytokine staining for IFN-gamma revealed that the LCMV-specific CD4(+) Thp frequency remains relatively stable following multiple heterologous virus infections or protein Ag immunizations, even under conditions that dramatically reduce the LCMV-specific CD8(+) CTL precursor frequency. These data indicate that the CD4(+) and CD8(+) memory T cell pools are regulated independently and that the loss in CD8(+) T cell memory following heterologous virus infections is not a consequence of a parallel loss in the memory CD4(+) T cell population.
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Affiliation(s)
- S M Varga
- Program in Immunology and Virology, University of Massachusetts Medical Center, Worcester, MA 01655, USA
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69
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Plunkett FJ, Soares MV, Annels N, Hislop A, Ivory K, Lowdell M, Salmon M, Rickinson A, Akbar AN. The flow cytometric analysis of telomere length in antigen-specific CD8+ T cells during acute Epstein-Barr virus infection. Blood 2001; 97:700-7. [PMID: 11157487 DOI: 10.1182/blood.v97.3.700] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Acute infectious mononucleosis (AIM) induced by Epstein-Barr virus (EBV) infection is characterized by extensive expansion of antigen-specific CD8+ T cells. One potential consequence of this considerable proliferative activity is telomere shortening, which predisposes the EBV-specific cells to replicative senescence. To investigate this, a method was developed that enables the simultaneous identification of EBV specificity of the CD8+ T cells, using major histocompatibility complex (MHC) class I/peptide complexes, together with telomere length, which is determined by fluorescence in situ hybridization. Despite the considerable expansion, CD8+ EBV-specific T cells in patients with AIM maintain their telomere length relative to CD8+ T cells in normal individuals and relative to CD4+ T cells within the patients themselves and this is associated with the induction of the enzyme telomerase. In 4 patients who were studied up to 12 months after resolution of AIM, telomere lengths of EBV-specific CD8+ T cells were unchanged in 3 but shortened in one individual, who was studied only 5 months after initial onset of infection. Substantial telomere shortening in EBV-specific CD8+ T cells was observed in 3 patients who were studied between 15 months and 14 years after recovery from AIM. Thus, although telomerase activation may preserve the replicative potential of EBV-specific cells in AIM and after initial stages of disease resolution, the capacity of these cells to up-regulate this enzyme after restimulation by the persisting virus may dictate the extent of telomere maintenance in the memory CD8+ T-cell pool over time.
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Affiliation(s)
- F J Plunkett
- Department of Clinical Immunology and Department of Haematology, Royal Free and University College Medical School, London, United Kingdom
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70
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Abstract
Rubella virus (RV) is the causative agent of the disease known more popularly as German measles. Rubella is predominantly a childhood disease and is endemic throughout the world. Natural infections of rubella occur only in humans and are generally mild. Complications of rubella infection, most commonly polyarthralgia in adult women, do exist; occasionally more serious sequelae occur. However, the primary public health concern of RV infection is its teratogenicity. RV infection of women during the first trimester of pregnancy can induce a spectrum of congenital defects in the newborn, known as congenital rubella syndrome (CRS). The development of vaccines and implementation of vaccination strategies have substantially reduced the incidence of disease and in turn of CRS in developed countries. The pathway whereby RV infection leads to teratogenesis has not been elucidated, but the cytopathology in infected fetal tissues suggests necrosis and/or apoptosis as well as inhibition of cell division of critical precursor cells involved in organogenesis. In cell culture, a number of unusual features of RV replication have been observed, including mitochondrial abnormalities, and disruption of the cytoskeleton; these manifestations are most probably linked and play some role in RV teratogenesis. Further understanding of the mechanism of RV teratogenesis will be brought about by the investigation of RV replication and virus-host interactions.
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71
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Sciortino MT, Perri D, Medici MA, Foti M, Orlandella BM, Mastino A. The gamma-2-herpesvirus bovine herpesvirus 4 causes apoptotic infection in permissive cell lines. Virology 2000; 277:27-39. [PMID: 11062033 DOI: 10.1006/viro.2000.0575] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increasing evidence suggests that regulation of apoptosis in infected cells is associated with several viral infections. The gammaherpesvirus bovine herpesvirus 4 (BHV-4) has been shown to harbor genes with antiapoptotic potentialities. However, here we have demonstrated that productive infection of adherent, permissive cell lines by BHV-4 resulted in a cytopathic effect characterized by induction of apoptosis. This phenomenon was confirmed using different techniques to detect apoptosis and using different virus strains and cell targets. Apoptosis induced by BHV-4 was inhibited by (1) treatment with doses of heparin, which completely inhibited virus attachment and infectivity; (2) UV treatment, which completely abrogated infectivity; and (3) treatment with a dose of phosphonoacetic acid, which blocked virus replication. Virus-induced apoptosis was associated with a down-regulation of Bcl-2 expression and was reduced by Z-VAD-FMK, but not by Z-DEVD-FMK (caspase-3-specific) caspase inhibitors. Inhibition of apoptosis by Z-VAD-FMK treatment during infection did not modify virus yield. Therefore, despite the presence of antiapoptotic genes in its genoma, BHV-4 could complete its cycle of productive infection while inducing apoptosis of infected cells. This finding might have implications for the pathobiology of BHV-4 and other gammaherpesviruses in vivo.
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Affiliation(s)
- M T Sciortino
- Department of Microbiological, Genetic, and Molecular Sciences, University of Messina, Messina, Italy.
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72
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Abstract
Rubella virus (RV) is the causative agent of the disease known more popularly as German measles. Rubella is predominantly a childhood disease and is endemic throughout the world. Natural infections of rubella occur only in humans and are generally mild. Complications of rubella infection, most commonly polyarthralgia in adult women, do exist; occasionally more serious sequelae occur. However, the primary public health concern of RV infection is its teratogenicity. RV infection of women during the first trimester of pregnancy can induce a spectrum of congenital defects in the newborn, known as congenital rubella syndrome (CRS). The development of vaccines and implementation of vaccination strategies have substantially reduced the incidence of disease and in turn of CRS in developed countries. The pathway whereby RV infection leads to teratogenesis has not been elucidated, but the cytopathology in infected fetal tissues suggests necrosis and/or apoptosis as well as inhibition of cell division of critical precursor cells involved in organogenesis. In cell culture, a number of unusual features of RV replication have been observed, including mitochondrial abnormalities, and disruption of the cytoskeleton; these manifestations are most probably linked and play some role in RV teratogenesis. Further understanding of the mechanism of RV teratogenesis will be brought about by the investigation of RV replication and virus-host interactions.
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Affiliation(s)
- J Y Lee
- Research and Molecular Development Division, Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria 3051, Australia.
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73
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Mori I, Kimura Y. Apoptotic neurodegeneration induced by influenza A virus infection in the mouse brain. Microbes Infect 2000; 2:1329-34. [PMID: 11018449 DOI: 10.1016/s1286-4579(00)01286-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Neurodegeneration in the brain induced by the WSN strain of influenza A virus was investigated after stereotaxic introduction into the olfactory bulb of C57BL/6 mice. Immunohistochemistry detected WSN virus-infected neurons in the anterior olfactory nucleus as early as day 3 postinfection. Thereafter, they became shrunken and showed loss of neurite-immunolabeling and chromatin condensation. Infected neurons died by day 12, degenerating into multiple small granular bodies. The terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling method demonstrated DNA fragmentation in infected neurons at day 7 and also in such granular bodies at day 12. In perforin-deficient mice, the appearance of virally induced apoptotic neurodegeneration was delayed and virus infection continued for a longer period of 35 days postinfection. These findings indicate that perforin-mediated neuroapoptosis appears significant in exterminating the intracellular pathogen at an early stage of infection.
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Affiliation(s)
- I Mori
- Department of Microbiology, Fukui Medical University School of Medicine, Shimoaizuki 23-3, Matsuoka-cho, Yoshida-gun, Fukui 910-1193, Japan
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74
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Abstract
Vaccines against a variety of infectious diseases represent one of the great triumphs of medicine. The immune correlates of protection induced by most current vaccines seem to be mediated by long-lived humoral immune responses. By contrast, there are no currently available vaccines that are uniformly effective for diseases such as HIV, malaria and tuberculosis, in which the cellular immune response might be crucial in mediating protection. Here we examine the mechanisms by which long-lived cellular immune responses are generated and maintained in vivo. We then discuss current approaches for vaccination against diseases in which cellular immune responses are important for protection.
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Affiliation(s)
- R A Seder
- Clinical Immunology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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75
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Abstract
Rabbit haemorrhagic disease virus (RHDV) causes an acute hepatitis and disseminated intravascular coagulation. Six rabbits were inoculated experimentally with RHDV to investigate any potential relationship between infection and apoptosis in the liver. Two rabbits were killed at 12 h post-inoculation (PI) and two at 24 h PI. The remaining two rabbits died at 30 h and 31 h PI. Immunohistochemical labelling for RHDV antigen-positive cells, TUNEL assay for apoptotic cells, and DNA analysis were performed on samples of liver. The four rabbits that died or were killed 24-31 h PI had acute hepatitis with infiltration of heterophils and necrotic hepatocytes. RHDV antigen-positive cells and apoptotic cells appeared in the centriacinar areas at 12 h PI; subsequently they spread to periacinar areas and increased in number, but the viral antigen-positive cells outnumbered apoptotic cells. At 24-31 h PI, few apoptotic cells were recognized in the areas infiltrated with lymphocytes and heterophils. The results suggested an association between RHDV infection and apoptosis of hepatocytes.
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Affiliation(s)
- J Y Jung
- Dept. of Veterinary Public Health and Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, 103 Seodun-dong, Kwonsun-Gu, Suwon, 441-744, Korea
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76
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Re MC, Monari P, Gibellini D, Ciancianaini P, Dall'Aglio PP, Vignoli M, Furlini G, Ramazzotti E, Bertazzoni U, Casoli C. Human T cell leukemia virus type II increases telomerase activity in uninfected CD34+ hematopoietic progenitor cells. JOURNAL OF HEMATOTHERAPY & STEM CELL RESEARCH 2000; 9:481-7. [PMID: 10982246 DOI: 10.1089/152581600419143] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aging process of long-term self-renewing hematopoietic stem/progenitor cells is not yet completely understood and recent studies on antiapoptotic cell pathways have demonstrated a close linkage between telomerase activation and Bcl-2 deregulation in human cancer cells. The present work shows that human T cell leukemia virus type II (HTLV-II) Mo virions that have originated from the T cell line (C344), but not from the B cell line (BJAB), are critically involved in mediating survival and growth effects on hematopoietic precursors (represented by both the TF-1 CD34+ cell line and by peripheral blood-derived CD34+ cells) through the maintenance or enhancement of telomerase activity and the induction of bcl-2 expression. In addition, using an interleukin-3-dependent TF-1 cell line, it was demonstrated that IL-3 deprivation was sufficient to influence the levels of telomerase activity and Bcl-2 expression in CD34+ cells. Taken together, these findings suggest that, in appropriate conditions, extended hematopoietic progenitor cell survival and proliferation following HTLV-II exposure depends on a synergistic interaction between up-regulation of Bcl-2 and activation of telomerase activity.
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Affiliation(s)
- M C Re
- Department of Clinical and Experimental Medicine, University of Bologna, Italy
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77
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Sato M, Mikami O, Kobayashi M, Nakajima Y. Apoptosis in the lymphatic organs of piglets inoculated with classical swine fever virus. Vet Microbiol 2000; 75:1-9. [PMID: 10865147 DOI: 10.1016/s0378-1135(00)00198-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The involvement of apoptosis in the lymphatic organs of piglets infected with classical swine fever (CSF) virus was investigated. Piglets were inoculated with CSF virus and 3, 5, 7 and 10 days post inoculation (DPI), the thymus, spleen and lymph node were examined. In the thymus cortex, macrophages phagocytizing the nuclear remnants or apoptotic bodies increased after 3 DPI. Thymus atrophy due to the loss of the cortex increased markedly during the observation period. Compact and shrunken nuclei indicating apoptosis were observed in the spleen and lymph node. DNA fragmentation was detected in the nuclei of lymphocytes in the thymus, spleen and lymph nodes, as well as at sites of focal necrosis. Using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method, ultrastructural characteristics of apoptosis, i.e. margination of condensed nuclear chromatin, were observed in the lymphatic organs from 2 DPI onward. These results suggest that apoptosis is involved in the pathology of CSF.
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Affiliation(s)
- M Sato
- Kyushu Research Station, National Institute of Animal Health, 2702 Chuzan, Kagoshima 891-0105, Kagoshima, Japan.
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78
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Abstract
CD8 T cells exist in a dynamic network whose repertoire remains static in the absence of infection but changes in the presence of foreign antigens. Individuals each have unique T-cell repertoires that continually evolve in the presence of antigen and of cross-reactive heterologous antigens, and homeostatic forces drive deletions in T-cell memory pools to accommodate the entry of new memory cells into a finite immune system.
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Affiliation(s)
- M Y Lin
- The Department of Pathology and Program in Immunology and Virology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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79
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Wick D, Self SG. Early HIV infection in vivo: branching-process model for studying timing of immune responses and drug therapy. Math Biosci 2000; 165:115-34. [PMID: 10854614 DOI: 10.1016/s0025-5564(00)00013-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We propose a stochastic, branching-process model of early events in vivo in human or simian immunodeficiency virus (HIV or SIV) infection and study the influence that the time of appearance of virus-specific antibodies or cytotoxic cells, or of administration of antiretroviral drugs, has on the probability of progression to a chronic infection. In some biological scenarios, our model predicts that a few days' delay in response or intervention would make little difference, while in others it would be highly deleterious. We show that prophylactic efficacy does not require perfect efficiency at neutralizing infectious virus. Data from a trial of PMPA, a potent antiretroviral drug, as post-exposure therapy for SIV infection in macaques, reported by C.-C. Tsai, P. Emau, K.E. Follis, T.W. Beck, R. E. Beneveniste, N. Bischofberger, J.D. Lifson, W.R. Morton (J. Virol. 72 (1998) 4265), provides a test of the model. We show that their observations are consistent with a branching-process without invoking supplementary viral- or host-variability. Finally, most animal trials of antiviral drugs or vaccines use very high viral inoculums; our model demonstrates that in such experiments we risk greatly underestimating the efficacy of these agents.
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Affiliation(s)
- D Wick
- Fred Hutchinson Cancer Research Center, MW-500, P.O. Box 19024, 1100 Fairview Avenue N, Seatle, WA 98109-1024, USA.
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80
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Shimokawa T, Okumura K, Ra C. DNA induces apoptosis in electroporated human promonocytic cell line U937. Biochem Biophys Res Commun 2000; 270:94-9. [PMID: 10733910 DOI: 10.1006/bbrc.2000.2388] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experimental gene transfer has permitted a wide variety of studies on gene regulation and function. However, possible effects of the introduced DNA on cellular metabolism are not well understood. Here we demonstrated that introduction of DNA into a promonocytic cell line, U937, by electroporation caused extensive cell death. The toxicity of DNA was concentration-dependent. Various DNAs including plasmid and genomic DNAs all caused cell death, indicating that the toxicity is nucleotide sequence-independent. DNA-induced cell death was associated with internucleosomal DNA fragmentation, a decrease in cell size, and a considerable proportion of cells outside cell cycle. From these results, we concluded that cells died by apoptosis. Our findings have experimental implication for an important issue concerning the interpretation of experiments using gene transfer. In addition, we propose that our observed phenomenon may be relevant to an important immune defense mechanism in monocytes/macrophages that facilitates a response to certain viral infections.
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Affiliation(s)
- T Shimokawa
- Allergy Research Center and Department of Immunology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
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81
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Connolly JL, Rodgers SE, Clarke P, Ballard DW, Kerr LD, Tyler KL, Dermody TS. Reovirus-induced apoptosis requires activation of transcription factor NF-kappaB. J Virol 2000; 74:2981-9. [PMID: 10708412 PMCID: PMC111796 DOI: 10.1128/jvi.74.7.2981-2989.2000] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Reovirus infection induces apoptosis in cultured cells and in vivo. To identify host cell factors that mediate this response, we investigated whether reovirus infection alters the activation state of the transcription factor nuclear factor kappa B (NF-kappaB). As determined in electrophoretic mobility shift assays, reovirus infection of HeLa cells leads to nuclear translocation of NF-kappaB complexes containing Rel family members p50 and p65. Reovirus-induced activation of NF-kappaB DNA-binding activity correlated with the onset of NF-kappaB-directed transcription in reporter gene assays. Three independent lines of evidence indicate that this functional form of NF-kappaB is required for reovirus-induced apoptosis. First, treatment of reovirus-infected HeLa cells with a proteasome inhibitor prevents NF-kappaB activation following infection and substantially diminishes reovirus-induced apoptosis. Second, transient expression of a dominant-negative form of IkappaB that constitutively represses NF-kappaB activation significantly reduces levels of apoptosis triggered by reovirus infection. Third, mutant cell lines deficient for either the p50 or p65 subunits of NF-kappaB are resistant to reovirus-induced apoptosis compared with cells expressing an intact NF-kappaB signaling pathway. These findings indicate that NF-kappaB plays a significant role in the mechanism by which reovirus induces apoptosis in susceptible host cells.
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Affiliation(s)
- J L Connolly
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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82
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Jones CM, Cose SC, McNally JM, Jennings SR, Heath WR, Carbone FR. Diminished secondary CTL response in draining lymph nodes on cutaneous challenge with herpes simplex virus. J Gen Virol 2000; 81:407-14. [PMID: 10644839 DOI: 10.1099/0022-1317-81-2-407] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have shown that C57BL/6-derived CD8(+) CTL specific for an immunodominant herpes simplex virus type 1 (HSV-1) glycoprotein B (gB) determinant express a highly conserved Vbeta10/junctional sequence combination. This extreme T cell receptor beta-chain bias can be used to track the activation of gB-specific CTL in lymph nodes draining the site of HSV-1 infection. In this report we have examined the accumulation of gB-specific CTL in the primary and secondary or recall CTL responses to HSV-1 infection. We found that gB-specific cytolytic activity present within popliteal lymph nodes draining HSV-infected foot-pads peaked at day 5 post-infection during the primary response. As found previously, this correlates with the accumulation of Vbeta10(+)CD8(+) CTL in the activated T cell subset. Lymph node-derived cytotoxicity peaked between days 3 and 4 on secondary challenge with virus and, somewhat surprisingly, was considerably below that seen in the primary response. This reduced gB-specific cytolytic activity mirrored a near absence of Vbeta10(+)CD8(+) T cell enrichment found within the draining lymph nodes during this recall response, consistent with the overall diminution of gB-specific CTL accumulation in this site. Finally, there was a second wave of biased accumulation of Vbeta10(+)CD8(+) activated T cells within the popliteal lymph nodes well after the resolution of infection in both the primary and secondary responses. These results are discussed in terms of preferential activation of virus-specific memory T cells directly in infected tissues during a secondary CTL response at the expense of draining lymphoid organs.
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Affiliation(s)
- C M Jones
- Department of Pathology, Monash Medical School, Commercial Road, Prahran, Victoria 3181, Australia
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83
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Abstract
Since the ancient times, natural products have served as a major source of drugs. About fifty percent of today's pharmaceutical drugs are derived from natural origin. Interest in natural products as a source of new drugs is growing due to many factors that will be discussed in this article. Viruses have been resistant to therapy or prophylaxis longer than any other form of life. Currently, there are only few drugs available for the cure of viral diseases including acyclovir which is modeled on a natural product parent. In order to combat viruses which have devastating effects on humans, animals, insects, crop plants, fungi and bacteria, many research efforts have been devoted for the discovery of new antiviral natural products. Recent analysis of the number and sources of antiviral agents reported mainly in the annual reports of medicinal chemistry from 1984 to 1995 indicated that seven out of ten synthetic agents approved by FDA between 1983-1994, are modeled on a natural product parent. It has been estimated that only 5-15% of the approximately 250,000 species of higher plants have been systematically investigated for the presence of bioactive compounds while the potential of the marine environment has barely been tapped. The aim of this review is to provide an overview on the central role of natural products in the discovery and development of new antiviral drugs by displaying 340 structures of plant, marine and microbial origin that show promising in vitro antiviral activity.
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84
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Henkin RI, Martin BM, Agarwal RP. Decreased parotid saliva gustin/carbonic anhydrase VI secretion: an enzyme disorder manifested by gustatory and olfactory dysfunction. Am J Med Sci 1999; 318:380-91. [PMID: 10616163 DOI: 10.1097/00000441-199912000-00005] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Taste and smell dysfunction has been reported to occur in patients with a variety of clinical problems. We wanted to investigate a specific group of patients in whom taste and smell dysfunction occurred putatively related to a specific biochemical abnormality in a salivary growth factor [gustin/carbonic anhydrase (CA) VI] considered responsible for maintenance of taste bud function. METHODS Eighteen patients developed loss and/or distortion of taste and smell after an acute influenza-type illness. They were evaluated clinically, by psychophysical tests of taste and smell function, by measurement of parotid salivary gustin/CAVI by a radioimmunoassay and by measurement of serum, urine, and salivary zinc. Biopsies of circumvallate papillae were obtained in 6 patients and examined by transmission electron microscopy. Similar studies were performed in 55 asymptomatic volunteers with biopsies of circumvallate papillae performed in 4. RESULTS Taste and smell acuity were impaired in patients compared with healthy volunteers and parotid gustin/CAVI, salivary, and serum zinc concentrations were lower in patients than in healthy volunteers. Taste buds in circumvallate papillae of patients exhibited severe vacuolization, cellular degeneration, and absence of dense extracellular material. CONCLUSIONS These results describe a clinical disorder formulated as a syndrome of hyposmia (decreased smell acuity), hypogeusia (decreased taste acuity), dysosmia (distorted smell function), dysgeusia (distorted taste function), and decreased secretion of parotid saliva gustin/CAVI with associated pathological changes in taste bud anatomy. Because gustin/CAVI is found in humans only in parotid saliva and has been associated with taste bud growth and development these results suggest that inhibition of synthesis of gustin/CAVI is associated with development of taste bud abnormalities and thereby loss of taste function.
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Affiliation(s)
- R I Henkin
- The Taste and Smell Clinic, Washington, DC 20016, USA
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85
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Decreased Parotid Saliva Gustin/Carbonic Anhydrase VI Secretion: An Enzyme Disorder Manifested by Gustatory and Olfactory Dysfunction. Am J Med Sci 1999. [DOI: 10.1016/s0002-9629(15)40663-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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86
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Abstract
Epstein-Barr virus (EBV) acute infectious mononucleosis (AIM) is characterized by transient immunosuppression in vivo and increased T-cell apoptosis after ex vivo culture of AIM peripheral blood mononuclear cells. We undertook experiments to test whether EBV or purified virion envelope glycoprotein gp350 could contribute to Fas-mediated T-cell apoptosis. Our in vitro results indicate that EBV increased Fas expression in CD4+ T cells and Fas ligand (FasL) expression in B cells and macrophages. Purified gp350 was also shown to significantly increase CD95 expression in CD4+ T cells. When T-cell CD95 was cross-linked, EBV-stimulated T cells underwent apoptosis. The induction of T-cell CD95 by EBV followed by CD95 cross-linking with anti-CD95 monoclonal antibody resulted in a loss in the number of T cells responding to the T-cell mitogens, anti-CD3 antibody, and interleukin-2. These results indicate that, in addition to serving as a principal ligand for the attachment of virus to target cells, gp350 may also act as an immunomodulatory molecule that promotes T-cell apoptosis.
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87
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Abstract
Hantaviruses replicate in primary and cultured animal cells with little or no cytopathic effect. We report here that the cultured Vero E6 cells infected by the Hantaan or by the Prospect Hill viruses exhibited characteristic features of apoptosis, including condensation and segmentation of nuclei and internucleosomal cleavage of nuclear DNA. Apoptosis was not seen in the cells adsorbed by UV-inactivated virus, indicating that the viral replication is required for the induction of apoptosis. Furthermore, level of the proto-oncogenic Bcl-2 protein was significantly reduced, whereas its mRNA level remained unchanged in Hantaan virus-infected cells, suggesting possible involvement and posttranscriptional regulation of this antiapoptotic protein in the process.
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Affiliation(s)
- J I Kang
- Graduate School of Biotechnology, Korea University, Seoul, 136-701, Korea
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88
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Moon KB, Turner PC, Moyer RW. SPI-1-dependent host range of rabbitpox virus and complex formation with cathepsin G is associated with serpin motifs. J Virol 1999; 73:8999-9010. [PMID: 10516006 PMCID: PMC112932 DOI: 10.1128/jvi.73.11.8999-9010.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/1999] [Accepted: 07/16/1999] [Indexed: 11/20/2022] Open
Abstract
Serpins are a superfamily of serine proteinase inhibitors which function to regulate a number of key biological processes including fibrinolysis, inflammation, and cell migration. Poxviruses are the only viruses known to encode functional serpins. While some poxvirus serpins regulate inflammation (myxoma virus SERP1 and cowpox virus [CPV] crmA/SPI-2) or apoptosis (myxoma virus SERP2 and CPV crmA/SPI-2), the function of other poxvirus serpins remains unknown. The rabbitpox virus (RPV) SPI-1 protein is 47% identical to crmA and shares all of the serpin structural motifs. However, no serpin-like activity has been demonstrated for SPI-1 to date. Earlier we showed that RPV with the SPI-1 gene deleted, unlike wild-type virus, fails to grow on A549 or PK15 cells (A. Ali, P. C. Turner, M. A. Brooks, and R. W. Moyer, Virology 202:306-314, 1994). Here we demonstrate that in the absence of a functional SPI-1 protein, infected nonpermissive cells which exhibit the morphological features of apoptosis fail to activate terminal caspases or cleave the death substrates PARP or lamin A. We show that SPI-1 forms a stable complex in vitro with cathepsin G, a member of the chymotrypsin family of serine proteinases, consistent with serpin activity. SPI-1 reactive-site loop (RSL) mutations of the critical P1 and P14 residues abolish this activity. Viruses containing the SPI-1 RSL P1 or P14 mutations also fail to grow on A549 or PK15 cells. These results suggest that the full virus host range depends on the serpin activity of SPI-1 and that in restrictive cells SPI-1 inhibits a proteinase with chymotrypsin-like activity and may function to inhibit a caspase-independent pathway of apoptosis.
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Affiliation(s)
- K B Moon
- Department of Molecular Genetics, University of Florida, Gainesville, Florida 32610-0266, USA
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89
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Yeung MC, Chang DL, Camantigue RE, Lau AS. Inhibitory role of the host apoptogenic gene PKR in the establishment of persistent infection by encephalomyocarditis virus in U937 cells. Proc Natl Acad Sci U S A 1999; 96:11860-5. [PMID: 10518541 PMCID: PMC18377 DOI: 10.1073/pnas.96.21.11860] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Persistent infections by viruses such as HIV-1 and hepatitis B virus can pose long-term health hazards. Because establishment of persistent infections involves close interactions and adjustments in both host and virus, it would be informative to establish a paradigm with which a normally cytolytic viral infection can be easily converted to persistent infection, so that the different stages in developing persistent infection can be examined. Such a model system is described in this paper. Highly cytolytic encephalomyocarditis virus (EMCV) infection was shifted to persistent infection as a result of repressed expression of the double-stranded RNA-dependent protein kinase (PKR) in the promonocytic U937 cells. Because of the apoptogenic potential of PKR, a deficiency of PKR resulted in a delay in virus-induced apoptosis in EMCV-infected U937 cells, allowing the eventual establishment of persistent EMCV infection in these cells (U9K-AV2). That this was a bona fide persistent infection was demonstrated by the ability of infected cells to propagate as long-term virus-shedding cultures; electron microscopy studies showing presence of intracellular EMCV virions and chromatin condensation; detection of virus-induced chromosomal DNA fragmentation and sustained expression of apoptogenic p53 and IL-1beta converting enzyme; and demonstration of active EMCV transcription by reverse transcription-PCR. In addition, a host-virus coevolution was observed in U9K-AV2 cultures over time: U9K-AV2 cells exhibited slower growth rates, resistance to viral super-infection, and cessation of IFN-alpha synthesis, whereas the infectivity of EMCV was drastically attenuated. Finally, data are presented on the suitability of this model to study establishment of persistent infection by other viruses such as Sendai virus and reovirus.
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Affiliation(s)
- M C Yeung
- The Moses Grossman Infectious Diseases Laboratory, San Francisco General Hospital, San Francisco, CA 94110, USA
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90
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Plymale DR, Tang DS, Comardelle AM, Fermin CD, Lewis DE, Garry RF. Both necrosis and apoptosis contribute to HIV-1-induced killing of CD4 cells. AIDS 1999; 13:1827-39. [PMID: 10513640 DOI: 10.1097/00002030-199910010-00004] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Data currently available on HIV-1-induced cytopathology is unclear regarding the mechanism of cell killing. OBJECTIVE To clarify the extent to which apoptosis or necrosis is involved in HIV-1-induced cell death in view of conflicting existing data. METHODS T lymphoblastoid cells or peripheral blood mononuclear cells were infected by various strains of HIV-1 and the numbers of apoptotic or necrotic cells were quantified at various times after infection using video-image analysis techniques; the results were compared with the amount of fragmented DNA using a quantitative method. Measurement of mitochondrial transmembrane potential (deltapsi(m)) and intracellular calcium concentrations [Ca2+]i was performed with fluorescent probes and fluorescence concentration analysis (FCA). RESULTS Although lymphoblastoid and monocytoid cells acutely infected by HIV-1 had increased levels of fragmented DNA, a marker of apoptotic cell death, few (<12%) had condensed chromatin and fragmented nuclei, the morphological features of apoptosis. The predominant alterations in acutely infected cells were distended endoplasmic reticulum and abnormal mitochondria; these ultrastructural changes are consistent with necrosis, although some infected cells simultaneously displayed features of both necrosis and apoptosis. Viability of cells persistently infected by HIV-1 was only minimally reduced from that of uninfected cells. This reduction was accounted for by an increased propensity of the persistently infected cells to die by apoptosis. Alterations in [Ca2+]i and deltapsi(m) occurred in both acutely and persistently infected cells. CONCLUSION Both necrosis and apoptosis contribute to HIV-1-induced killing of CD4 cells.
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Affiliation(s)
- D R Plymale
- Interdisciplinary Graduate Program in Molecular and Cellular Biology, Tulane University, New Orleans, Louisiana 70112, USA
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91
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Atkins GJ, Sheahan BJ, Liljeström P. The molecular pathogenesis of Semliki Forest virus: a model virus made useful? J Gen Virol 1999; 80 ( Pt 9):2287-2297. [PMID: 10501479 DOI: 10.1099/0022-1317-80-9-2287] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Gregory J Atkins
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland1
| | - Brian J Sheahan
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, University College Dublin, Dublin 4, Ireland2
| | - Peter Liljeström
- Department of Vaccine Research, Swedish Institute for Infectious Disease Control, S-171 82 Solna, Sweden4
- Microbiology and Tumorbiology Center, Karolinska Institute, S-171 77 Stockholm, Sweden3
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92
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Welsh RM, McNally JM. Immune deficiency, immune silencing, and clonal exhaustion of T cell responses during viral infections. Curr Opin Microbiol 1999; 2:382-7. [PMID: 10458980 DOI: 10.1016/s1369-5274(99)80067-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Analyses of the complex regulatory networks leading to T cell survival, death, and immune deficiency have been aided in the past year by the dramatic development of new technologies to identify T cells and assess T cell function. These new techniques have shown that functional inactivation and apoptotic elimination of both virus-specific and non-virus-specific T cell populations mold T cell responses to viral infections.
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Affiliation(s)
- R M Welsh
- Department of Pathology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
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93
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Abstract
Human cytomegalovirus is ubiquitous, yet causes little illness in immunocompetent individuals. Disease is evident in immunodeficient groups such as neonates, transplant recipients and AIDS patients either following a primary infection or reactivation of a latent infection. Little is known of the mechanisms underlying the pathogenicity of the virus. The recent determination of the nucleotide sequence of both human cytomegalovirus (strain AD169) and murine cytomegalovirus (murine cytomegalovirus strain Smith) has allowed an analysis of the biological importance of several virus genes. Studies with human cytomegalovirus have indicated that many viral genes are non-essential for replication in vitro which are thus assumed to be important in the pathogenesis of the virus. This is being examined in the murine model where the role of the gene and its product in disease can be directly examined in vivo using viral mutants in which the relevant gene has been interrupted or deleted. Current information on the role of cytomegalovirus genes in tissue tropism, immune evasion, latency, reactivation from latency and damage is described.
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Affiliation(s)
- C Sweet
- School of Biological Sciences, University of Birmingham, UK.
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94
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Megyeri K, Berencsi K, Halazonetis TD, Prendergast GC, Gri G, Plotkin SA, Rovera G, Gönczöl E. Involvement of a p53-dependent pathway in rubella virus-induced apoptosis. Virology 1999; 259:74-84. [PMID: 10364491 DOI: 10.1006/viro.1999.9757] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In light of the important role of apoptotic cell death in the pathogenesis of several viral infections, we asked whether the cytopathogenicity evoked by rubella virus (RV) might also involve apoptotic mechanisms. The To-336 strain of RV induced apoptosis in Vero and RK-13 cells, but not in fibroblast cell lines. UV-inactivated RV virions did not elicit the apoptotic response, indicating that productive infection is required for the induction of cell death. Both p53 and p21 protein levels were highly elevated in RV-infected Vero cells. The level of p21 mRNA was increased, while expression of the p53 gene was unaffected by RV infection. A dominant-negative p53 mutant (p53(W248)) conferred partial protection from RV-induced apoptosis. These data implicate a p53-dependent apoptotic pathway in the cytopathogenicity of RV, thereby suggesting a mechanism by which RV exerts its teratogenic effects.
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Affiliation(s)
- K Megyeri
- The Wistar Institute, 3601 Spruce Street, Philadelphia, Pennsylvania, 19104, USA
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95
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Abstract
Viruses have evolved numerous strategies to modulate the host response to infection. Poxviruses cause acute infections and need to replicate quickly to promote efficient transmission. Consequently, it is not surprising to learn that poxviruses encode a large number of proteins designed to target various arms of the host inflammatory response. One of the earliest described and most well-studied viral modulatory proteins is crmA/SPI-2. While the biochemical targets and possible modes of action have been well characterized in vitro, the role that crmA/SPI-2 plays during natural infection is less clear. It may have effects in modulating host responses involving apoptosis and inflammation. It is important to further understand the precise mode of action of viral proteins, such as crmA/SPI-2, because this may lead to better therapeutic strategies to combat a range of inflammatory and autoimmune diseases.
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Affiliation(s)
- S Turner
- Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria, Australia.
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96
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Devireddy LR, Jones CJ. Activation of caspases and p53 by bovine herpesvirus 1 infection results in programmed cell death and efficient virus release. J Virol 1999; 73:3778-88. [PMID: 10196272 PMCID: PMC104155 DOI: 10.1128/jvi.73.5.3778-3788.1999] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Programmed cell death (PCD), or apoptosis, is initiated in response to various stimuli, including virus infection. Bovine herpesvirus 1 (BHV-1) induces PCD in peripheral blood mononuclear cells at the G0/G1 phase of the cell cycle (E. Hanon, S. Hoornaert, F. Dequiedt, A. Vanderplasschen, J. Lyaku, L. Willems, and P.-P. Pastoret, Virology 232:351-358, 1997). However, penetration of virus particles is not required for PCD (E. Hanon, G. Meyer, A. Vanderplasschen, C. Dessy-Doize, E. Thiry, and P. P. Pastoret, J. Virol. 72:7638-7641, 1998). The mechanism by which BHV-1 induces PCD in peripheral blood mononuclear cells is not understood, nor is it clear whether nonlymphoid cells undergo PCD following infection. This study demonstrates that infection of bovine kidney (MDBK) cells with BHV-1 leads to PCD, as judged by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling, DNA laddering, and chromatin condensation. p53 appears to be important in this process, because p53 levels and promoter activity increased after infection. Expression of proteins that are stimulated by p53 (p21(Waf1) and Bax) is also activated after infection. Cleavage of Bcl-xL, a protein that inhibits PCD, occurred after infection, suggesting that caspases (interleukin-1beta-converting enzyme-like proteases) were activated. Other caspase substrates [poly(ADP-ribose) polymerase and actin] are also cleaved during the late stages of infection. Inhibition of caspase activity delayed cytotoxic activity and virus release but increased the overall virus yield. Taken together, these results indicate that nonlymphoid cells undergo PCD near the end of productive infection and further suggest that caspases enhance virus release.
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Affiliation(s)
- L R Devireddy
- Department of Veterinary and Biomedical Sciences, Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0905, USA
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97
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Opferman JT, Ober BT, Ashton-Rickardt PG. Linear differentiation of cytotoxic effectors into memory T lymphocytes. Science 1999; 283:1745-8. [PMID: 10073942 DOI: 10.1126/science.283.5408.1745] [Citation(s) in RCA: 299] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A central question in immunology is the origin of long-lived T cell memory that confers protection against recurrent infection. The differentiation of naïve T cell receptor transgenic CD8+ cells into effector cytotoxic T lymphocytes (CTLs) and memory CD8+ cells was studied. Memory CD8+ cells that were generated after strong antigenic stimulation were the progeny of cytotoxic effectors and retained antigen-specific cytolytic activity 10 weeks after adoptive transfer to antigen-free recipient mice. Thus, potential vaccines based on CTL memory will require the differentiation of naïve cells into post-effector memory T cells.
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Affiliation(s)
- J T Opferman
- Committee on Immunology, Department of Pathology, Committee on Developmental Biology, The University of Chicago, Gwen Knapp Center for Lupus and Immunology Research, Chicago, IL 60637, USA
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98
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Duncan R, Muller J, Lee N, Esmaili A, Nakhasi HL. Rubella virus-induced apoptosis varies among cell lines and is modulated by Bcl-XL and caspase inhibitors. Virology 1999; 255:117-28. [PMID: 10049827 DOI: 10.1006/viro.1998.9562] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rubella virus (RV) causes multisystem birth defects in the fetuses of infected women. To investigate the cellular basis of this pathology, we examined the cytopathic effect of RV in three permissive cell lines: Vero 76, RK13, and BHK21. Electron microscopy and the TUNEL assay showed that the cytopathic effect resulted from RV-induced programmed cell death (apoptosis) in all three cell lines, but the extent of apoptosis varied among these cells. At 48 h postinfection, the RK13 cell line showed the greatest number of apoptotic cells, the Vero 76 cell line was approximately 3-fold less, and BHK21 had very few. An increased multiplicity of infection and longer time postinfection were required for the BHK21 cell line to reach the level of apoptotic cells in Vero 76 at 48 h. Purified RV induced apoptosis in a dose-dependent fashion, but not UV-inactivated RV or virus-depleted culture supernatant. Specific inhibitors of the apoptosis-specific proteases caspases reduced RV-induced apoptosis and led to higher levels of RV components in infected cells. To address the role of regulatory proteins in RV-induced apoptosis, the antiapoptotic gene Bcl-2 or Bcl-XL was transfected into RK13 cells. Although a high level of Bcl-2 family proteins was expressed, no protection was observed from apoptosis induced by RV, Sindbis virus, or staurosporine in RK13 cells. In BHK21 cells, however, increased expression of Bcl-XL protected cells from apoptosis. The observed variability in apoptotic response to RV of these cell lines demonstrates that programmed cell death is dependent on the unique properties of each cell and may be indicative of how selective organ damage occurs in a congenital rubella syndrome fetus.
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Affiliation(s)
- R Duncan
- Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA
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99
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Martín Duque P, Alonso C, Sánchez-Prieto R, Lleonart M, Ramón y Cajal S. Antitumor effect of E1B defective adenoviruses in human malignant cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 451:87-9. [PMID: 10026855 DOI: 10.1007/978-1-4615-5357-1_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- P Martín Duque
- Departamento de Patología, Clínica Pta de Hierro, Madrid, Spain
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100
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Dequiedt F, Cantor GH, Hamilton VT, Pritchard SM, Davis WC, Kerkhofs P, Burny A, Kettmann R, Willems L. Bovine leukemia virus-induced persistent lymphocytosis in cattle does not correlate with increased ex vivo survival of B lymphocytes. J Virol 1999; 73:1127-37. [PMID: 9882314 PMCID: PMC103933 DOI: 10.1128/jvi.73.2.1127-1137.1999] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bovine leukemia virus (BLV) is an oncogenic retrovirus associated with B-cell lymphocytosis, leukemia, and lymphosarcoma in the ovine and bovine species. We have recently reported that in sheep, BLV protects the total population of peripheral blood mononuclear cells (PBMCs) from ex vivo spontaneous apoptosis. This global decrease in the apoptosis rates resulted from both direct and indirect mechanisms which allow extension of cell survival. Although sheep are not natural hosts for BLV, these animals are prone to develop virus-induced leukemia at very high frequencies. Most infected cattle, however, remain clinically healthy. This difference in the susceptibilities to development of leukemia in these two species might be related to alterations of the apoptotic processes. Therefore, we designed this study to unravel the mechanisms of programmed cell death in cattle. We have observed that PBMCs from persistently lymphocytotic BLV-infected cows were more susceptible to spontaneous ex vivo apoptosis than cells from uninfected or aleukemic animals. These higher apoptosis rates were the consequence of an increased proportion of B cells exhibiting lower survival abilities. About one-third of the BLV-expressing cells did not survive the ex vivo culture conditions, demonstrating that viral expression is not strictly associated with cell survival in cattle. Surprisingly, culture supernatants from persistently lymphocytotic cows exhibited efficient antiapoptotic properties on both uninfected bovine and uninfected ovine cells. It thus appears that indirect inhibition of cell death can occur even in the presence of high apoptosis rates. Together, these results demonstrate that the protection against spontaneous apoptosis associated with BLV is different in cattle and in sheep. The higher levels of ex vivo apoptosis occurring in cattle might indicate a decreased susceptibility to development of leukemia in vivo.
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Affiliation(s)
- F Dequiedt
- Department of Applied Biochemistry and Biology, Molecular Biology and Animal Physiology Unit, Faculty of Agronomy, B5030 Gembloux, Belgium.
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