101
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Zheng N, Xia R, Yang C, Yin B, Li Y, Duan C, Liang L, Guo H, Xie Q. Boosted expression of the SARS-CoV nucleocapsid protein in tobacco and its immunogenicity in mice. Vaccine 2009; 27:5001-7. [PMID: 19523911 PMCID: PMC7115566 DOI: 10.1016/j.vaccine.2009.05.073] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 05/20/2009] [Accepted: 05/26/2009] [Indexed: 12/18/2022]
Abstract
Vaccines produced in plant systems are safe and economical; however, the extensive application of plant-based vaccines is mainly hindered by low expression levels of heterologous proteins in plant systems. Here, we demonstrated that the post-transcriptional gene silencing suppressor p19 protein from tomato bushy stunt virus substantially enhanced the transient expression of recombinant SARS-CoV nucleocapsid (rN) protein in Nicotiana benthamiana. The rN protein in the agrobacteria-infiltrated plant leaf accumulated up to a concentration of 79 microg per g fresh leaf weight at 3 days post infiltration. BALB/c mice were intraperitoneally vaccinated with pre-treated plant extract emulsified in Freund's adjuvant. The rN protein-specific IgG in the mouse sera attained a titer about 1:1,800 following three doses of immunization, which suggested effective B-cell maturation and differentiation in mice. Antibodies of the subclasses IgG1 and IgG2a were abundantly present in the mouse sera. During vaccination of rN protein, the expression of IFN-gamma and IL-10 was evidently up-regulated in splenocytes at different time points, while the expression of IL-2 and IL-4 was not. Up to now, this is the first study that plant-expressed recombinant SARS-CoV N protein can induce strong humoral and cellular responses in mice.
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MESH Headings
- Adjuvants, Immunologic/administration & dosage
- Adjuvants, Immunologic/pharmacology
- Animals
- Antibodies, Viral/blood
- Coronavirus Nucleocapsid Proteins
- Female
- Freund's Adjuvant/administration & dosage
- Freund's Adjuvant/pharmacology
- Gene Silencing
- Humans
- Immunoglobulin G/blood
- Injections, Intraperitoneal
- Interferon-gamma/metabolism
- Interleukin-10/metabolism
- Leukocytes, Mononuclear/immunology
- Mice
- Mice, Inbred BALB C
- Nucleocapsid Proteins/genetics
- Nucleocapsid Proteins/immunology
- Nucleocapsid Proteins/isolation & purification
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Recombinant Proteins/isolation & purification
- Severe acute respiratory syndrome-related coronavirus/genetics
- Severe acute respiratory syndrome-related coronavirus/immunology
- Spleen/immunology
- Nicotiana/genetics
- Nicotiana/metabolism
- Tombusvirus/genetics
- Vaccines, Subunit/genetics
- Vaccines, Subunit/immunology
- Vaccines, Subunit/isolation & purification
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Affiliation(s)
- Nuoyan Zheng
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Beijing 100101, China
- State Key Laboratory for Biocontrol, Sun Yat-sen (Zhongshan) University, 135 Xingang Road W, Guangzhou 510275, China
| | - Ran Xia
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Beijing 100101, China
| | - Cuiping Yang
- State Key Laboratory for Biocontrol, Sun Yat-sen (Zhongshan) University, 135 Xingang Road W, Guangzhou 510275, China
| | - Bojiao Yin
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Beijing 100101, China
- State Key Laboratory for Biocontrol, Sun Yat-sen (Zhongshan) University, 135 Xingang Road W, Guangzhou 510275, China
| | - Yin Li
- State Key Laboratory for Biocontrol, Sun Yat-sen (Zhongshan) University, 135 Xingang Road W, Guangzhou 510275, China
| | - Chengguo Duan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
| | - Liming Liang
- State Key Laboratory for Biocontrol, Sun Yat-sen (Zhongshan) University, 135 Xingang Road W, Guangzhou 510275, China
| | - Huishan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Beijing 100101, China
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102
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Moxnes JF, Albert christophersen O. The Spanish flu as a worst case scenario? MICROBIAL ECOLOGY IN HEALTH AND DISEASE 2009. [DOI: 10.1080/08910600701699067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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103
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Siu KL, Chan CP, Chan C, Zheng BJ, Jin DY. Severe acute respiratory syndrome coronavirus nucleocapsid protein does not modulate transcription of the human FGL2 gene. J Gen Virol 2009. [PMID: 19423547 DOI: v10.1099/vir.0.009209-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Among the structural and nonstructural proteins of severe acute respiratory syndrome coronavirus (SARS-CoV), the nucleocapsid (N) protein plays pivotal roles in the biology and pathogenesis of viral infection. N protein is thought to dysregulate cell signalling and the transcription of cellular genes, including FGL2, which encodes a prothrombinase implicated in vascular thrombosis, fibrin deposition and pneumocyte necrosis. Here, we showed that N protein expressed in cultured human cells was predominantly found in the cytoplasm and was competent in repressing the transcriptional activity driven by interferon-stimulated response elements. However, the expression of N protein did not influence the transcription from the FGL2 promoter. More importantly, N protein did not modulate the expression of FGL2 mRNA or protein in transfected or SARS-CoV-infected cells. Taken together, our findings did not support the model in which SARS-CoV N protein specifically modulates transcription of the FGL2 gene to cause fibrosis and vascular thrombosis.
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Affiliation(s)
- Kam-Leung Siu
- Department of Biochemistry, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
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104
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Siu KL, Chan CP, Chan C, Zheng BJ, Jin DY. Severe acute respiratory syndrome coronavirus nucleocapsid protein does not modulate transcription of the human FGL2 gene. J Gen Virol 2009; 90:2107-13. [PMID: 19423547 DOI: 10.1099/vir.0.009209-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Among the structural and nonstructural proteins of severe acute respiratory syndrome coronavirus (SARS-CoV), the nucleocapsid (N) protein plays pivotal roles in the biology and pathogenesis of viral infection. N protein is thought to dysregulate cell signalling and the transcription of cellular genes, including FGL2, which encodes a prothrombinase implicated in vascular thrombosis, fibrin deposition and pneumocyte necrosis. Here, we showed that N protein expressed in cultured human cells was predominantly found in the cytoplasm and was competent in repressing the transcriptional activity driven by interferon-stimulated response elements. However, the expression of N protein did not influence the transcription from the FGL2 promoter. More importantly, N protein did not modulate the expression of FGL2 mRNA or protein in transfected or SARS-CoV-infected cells. Taken together, our findings did not support the model in which SARS-CoV N protein specifically modulates transcription of the FGL2 gene to cause fibrosis and vascular thrombosis.
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Affiliation(s)
- Kam-Leung Siu
- Department of Biochemistry, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
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105
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Yasui F, Kai C, Kitabatake M, Inoue S, Yoneda M, Yokochi S, Kase R, Sekiguchi S, Morita K, Hishima T, Suzuki H, Karamatsu K, Yasutomi Y, Shida H, Kidokoro M, Mizuno K, Matsushima K, Kohara M. Prior immunization with severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) nucleocapsid protein causes severe pneumonia in mice infected with SARS-CoV. THE JOURNAL OF IMMUNOLOGY 2009; 181:6337-48. [PMID: 18941225 DOI: 10.4049/jimmunol.181.9.6337] [Citation(s) in RCA: 197] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The details of the mechanism by which severe acute respiratory syndrome-associated coronavirus (SARS-CoV) causes severe pneumonia are unclear. We investigated the immune responses and pathologies of SARS-CoV-infected BALB/c mice that were immunized intradermally with recombinant vaccinia virus (VV) that expressed either the SARS-CoV spike (S) protein (LC16m8rVV-S) or simultaneously all the structural proteins, including the nucleocapsid (N), membrane (M), envelope (E), and S proteins (LC16m8rVV-NMES) 7-8 wk before intranasal SARS-CoV infection. The LC16m8rVV-NMES-immunized group exhibited as severe pneumonia as the control groups, although LC16m8rVV-NMES significantly decreased the pulmonary SARS-CoV titer to the same extent as LC16m8rVV-S. To identify the cause of the exacerbated pneumonia, BALB/c mice were immunized with recombinant VV that expressed the individual structural proteins of SARS-CoV (LC16mOrVV-N, -M, -E, -S) with or without LC16mOrVV-S (i.e., LC16mOrVV-N, LC16mOrVV-M, LC16mOrVV-E, or LC16mOrVV-S alone or LC16mOrVV-N + LC16mOrVV-S, LC16mOrVV-M + LC16mOrVV-S, or LC16mOrVV-E + LC16mOrVV-S), and infected with SARS-CoV more than 4 wk later. Both LC16mOrVV-N-immunized mice and LC16mOrVV-N + LC16mOrVV-S-immunized mice exhibited severe pneumonia. Furthermore, LC16mOrVV-N-immunized mice upon infection exhibited significant up-regulation of both Th1 (IFN-gamma, IL-2) and Th2 (IL-4, IL-5) cytokines and down-regulation of anti-inflammatory cytokines (IL-10, TGF-beta), resulting in robust infiltration of neutrophils, eosinophils, and lymphocytes into the lung, as well as thickening of the alveolar epithelium. These results suggest that an excessive host immune response against the nucleocapsid protein of SARS-CoV is involved in severe pneumonia caused by SARS-CoV infection. These findings increase our understanding of the pathogenesis of SARS.
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Affiliation(s)
- Fumihiko Yasui
- Department of Microbiology and Cell Biology, The Tokyo Metropolitan Institute of Medical Science, Japan
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106
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Xia LM, Huang WJ, Wu JG, Yang YB, Zhang Q, Zhou ZZ, Zhu HF, Lei P, Shen GX, Tian DA. HBx protein induces expression of MIG and increases migration of leukocytes through activation of NF-kappaB. Virology 2009; 385:335-42. [PMID: 19157479 DOI: 10.1016/j.virol.2008.11.042] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 11/18/2008] [Accepted: 11/25/2008] [Indexed: 01/12/2023]
Abstract
Elevated expression of monokine induced by the interferon-gamma (MIG) has been shown in HBV carriers, and it is involved in the infiltration of inflammatory cells and liver damage after HBV infection. However, the molecular mechanisms by which HBV-induced MIG expression have not been characterized. Our results indicated that HBx protein induced MIG expression in a dose-dependent manner. Such increase was due to the direct binding of NF-kappaB to the MIG promoter. By luciferase, chromatin immunoprecipitation and electrophoretic mobility shift assays, we demonstrated that the NF-kappaB binding site at positions -147 was essential for transcriptional activation of MIG promoter by HBx protein. Chemotaxis assay showed that the up-regulation of MIG protein levels enhanced the migration of peripheral blood lymphocytes (PBLs), and inhibition of NF-kappaB significantly decreased the chemotaxis activity. Our findings provide a new insight into how leukocytes migrate to liver, and disclose a new regulatory mechanism of MIG expression after HBV infection.
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Affiliation(s)
- Li-Min Xia
- Division of Gastroenterology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei Province, People's Republic of China
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107
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Severe acute respiratory syndrome coronavirus infection causes neuronal death in the absence of encephalitis in mice transgenic for human ACE2. J Virol 2008; 82:7264-75. [PMID: 18495771 DOI: 10.1128/jvi.00737-08] [Citation(s) in RCA: 926] [Impact Index Per Article: 57.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection of humans with the severe acute respiratory syndrome coronavirus (SARS-CoV) results in substantial morbidity and mortality, with death resulting primarily from respiratory failure. While the lungs are the major site of infection, the brain is also infected in some patients. Brain infection may result in long-term neurological sequelae, but little is known about the pathogenesis of SARS-CoV in this organ. We previously showed that the brain was a major target organ for infection in mice that are transgenic for the SARS-CoV receptor (human angiotensin-converting enzyme 2). Herein, we use these mice to show that virus enters the brain primarily via the olfactory bulb, and infection results in rapid, transneuronal spread to connected areas of the brain. This extensive neuronal infection is the main cause of death because intracranial inoculation with low doses of virus results in a uniformly lethal disease even though little infection is detected in the lungs. Death of the animal likely results from dysfunction and/or death of infected neurons, especially those located in cardiorespiratory centers in the medulla. Remarkably, the virus induces minimal cellular infiltration in the brain. Our results show that neurons are a highly susceptible target for SARS-CoV and that only the absence of the host cell receptor prevents severe murine brain disease.
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108
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Diemer C, Schneider M, Seebach J, Quaas J, Frösner G, Schätzl HM, Gilch S. Cell type-specific cleavage of nucleocapsid protein by effector caspases during SARS coronavirus infection. J Mol Biol 2007; 376:23-34. [PMID: 18155731 PMCID: PMC7094231 DOI: 10.1016/j.jmb.2007.11.081] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2007] [Revised: 11/20/2007] [Accepted: 11/26/2007] [Indexed: 12/30/2022]
Abstract
The epidemic outbreak of severe acute respiratory syndrome (SARS) in 2003 was caused by a novel coronavirus (CoV), designated SARS-CoV. The RNA genome of SARS-CoV is complexed by the nucleocapsid protein (N) to form a helical nucleocapsid. Besides this primary function, N seems to be involved in apoptotic scenarios. We show that upon infection of Vero E6 cells with SARS-CoV, which elicits a pronounced cytopathic effect and a high viral titer, N is cleaved by caspases. In contrast, in SARS-CoV-infected Caco-2 cells, which show a moderate cytopathic effect and a low viral titer, this processing of N was not observed. To further verify these observations, we transiently expressed N in different cell lines. Caco-2 and N2a cells served as models for persistent SARS-CoV infection, whereas Vero E6 and A549 cells did as prototype cell lines lytically infected by SARS-CoV. The experiments revealed that N induces the intrinsic apoptotic pathway, resulting in processing of N at residues 400 and 403 by caspase-6 and/or caspase-3. Of note, caspase activation is highly cell type specific in SARS-CoV-infected as well as transiently transfected cells. In Caco-2 and N2a cells, almost no N-processing was detectable. In Vero E6 and A549 cells, a high proportion of N was cleaved by caspases. Moreover, we examined the subcellular localization of SARS-CoV N in these cell lines. In transfected Vero E6 and A549 cells, SARS-CoV N was localized both in the cytoplasm and nucleus, whereas in Caco-2 and N2a cells, nearly no nuclear localization was observed. In addition, our studies indicate that the nuclear localization of N is essential for its caspase-6-mediated cleavage. These data suggest a correlation among the replication cycle of SARS-CoV, subcellular localization of N, induction of apoptosis, and the subsequent activation of caspases leading to cleavage of N.
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Affiliation(s)
- Claudia Diemer
- Institute of Virology, Technical University of Munich, Trogerstr. 30, 81675 Munich, Germany
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