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Meng F, Zhao Z, Li G, Suo S, Shi N, Yin J, Zarlenga D, Ren X. Bacterial expression of antigenic sites A and D in the spike protein of transmissible gastroenteritis virus and evaluation of their inhibitory effects on viral infection. Virus Genes 2011; 43:335-41. [PMID: 21701858 PMCID: PMC7089297 DOI: 10.1007/s11262-011-0637-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 06/11/2011] [Indexed: 11/03/2022]
Abstract
The spike (S) protein is a key structural protein of coronaviruses including, the porcine transmissible gastroenteritis virus (TGEV). The S protein is a type I membrane glycoprotein located in the viral envelope and is responsible for mediating the binding of viral particles to specific cell receptors and therefore specific cell types. It is also an important immune target for the host in neutralizing the virus. Four antigenic sites A, B, C, and D that reside near the N-terminal domain have been defined in the S protein. Of these, the region encoding antigenic sites A and to a lesser extent D, herein defined as S-AD, are most critical in eliciting host neutralizing antibodies. Herein, we enzymatically amplified, cloned, and expressed the S-AD fragment from TGEV in the prokaryotic expression vector, pET-30a. Maximum protein expression was achieved at 30°C over a 5-h period post-induction. Rabbit polyclonal antiserum was generated using recombinant S-AD (rS-AD) protein. In contrast to prior studies showing no activity with bacterially produced S protein, results indicated that polyclonal serum recognized TGEV-infected cells and reduced infection by 100%. Furthermore, the truncated rS-AD peptide was able to bind to the surface of cells from swine testes in a competitive manner and completely inhibit viral infection.
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Affiliation(s)
- Fandan Meng
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
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2
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Ren X, Liu B, Yin J, Zhang H, Li G. Phage displayed peptides recognizing porcine aminopeptidase N inhibit transmissible gastroenteritis coronavirus infection in vitro. Virology 2010; 410:299-306. [PMID: 21176936 PMCID: PMC7111919 DOI: 10.1016/j.virol.2010.11.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 06/22/2010] [Accepted: 11/16/2010] [Indexed: 12/03/2022]
Abstract
Porcine aminopeptidase N (pAPN) is a cellular receptor of transmissible gastroenteritis virus (TGEV), a porcine coronavirus. Interaction between the spike (S) protein of TGEV and pAPN initiates cell infection. Small molecules, especially peptides are an expanding area for therapy or diagnostic assays for viral diseases. Here, the peptides capable of binding the pAPN were, for the first time, identified by biopanning using a random 12-mer peptide library to the immobilized protein. Three chemically synthesized peptides recognizing the pAPN showed effective inhibition ability to TGEV infection in vitro. A putative TxxF motif was identified in the S protein of TGEV. Phages bearing the specific peptides interacted with the pAPN in ELISA. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays confirmed the protective effect of the peptides on cell infection by TGEV. Moreover, the excellent immune responses in mice induced by the identified phages provided the possibility to develop novel phage-based vaccines.
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Affiliation(s)
- Xiaofeng Ren
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China
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3
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Dosch SF, Mahajan SD, Collins AR. SARS coronavirus spike protein-induced innate immune response occurs via activation of the NF-kappaB pathway in human monocyte macrophages in vitro. Virus Res 2009; 142:19-27. [PMID: 19185596 PMCID: PMC2699111 DOI: 10.1016/j.virusres.2009.01.005] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Accepted: 01/09/2009] [Indexed: 12/12/2022]
Abstract
A purified recombinant spike (S) protein was studied for its effect on stimulating human peripheral blood monocyte macrophages (PBMC). We examined inflammatory gene mRNA abundances found in S protein-treated PBMC using gene arrays. We identified differential mRNA abundances of genes with functional properties associated with antiviral (CXCL10) and inflammatory (IL-6 and IL-8) responses. We confirmed cytokine mRNA increases by real-time quantitative(q) RT-PCR or ELISA. We further analyzed the sensitivity and specificity of the prominent IL-8 response. By real-time qRT-PCR, S protein was shown to stimulate IL-8 mRNA accumulation in a dose dependent manner while treatment with E protein did not. Also, titration of S protein-specific production and secretion of IL-8 by ELISA showed that the dose of 5.6nM of S produced a significant increase in IL-8 (p=0.003) compared to mock-treated controls. The increase in IL-8 stimulated by a concentration of 5.6nM of S was comparable to concentrations seen for S protein binding to ACE2 or to neutralizing monoclonal antibody suggesting a physiological relevance. An NF-kappaB inhibitor, TPCK (N-Tosyl-L-Phenylalanine Chloromethyl Ketone) could suppress IL-8 production and secretion in response to S protein in PBMC and THP-1 cells and in HCoV-229E virus-infected PBMC. Activation and translocation of NF-kappaB was shown to occur rapidly following exposure of PBMC or THP-1 cells to S protein using a highly sensitive assay for active nuclear NF-kappaB p65 transcription factor. The results further suggested that released or secreted S protein could activate blood monocytes through recognition by toll-like receptor (TLR)2 ligand.
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Affiliation(s)
- Susan F. Dosch
- Department of Microbiology and Immunology, Division of Allergy, Immunology and Rheumatology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Supriya D. Mahajan
- Department of Medicine, Division of Allergy, Immunology and Rheumatology, State University of New York at Buffalo, Buffalo, NY, United States
| | - Arlene R. Collins
- Department of Microbiology and Immunology, Division of Allergy, Immunology and Rheumatology, State University of New York at Buffalo, Buffalo, NY, United States
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4
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Chan CM, Woo PCY, Lau SKP, Tse H, Chen HL, Li F, Zheng BJ, Chen L, Huang JD, Yuen KY. Spike protein, S, of human coronavirus HKU1: role in viral life cycle and application in antibody detection. Exp Biol Med (Maywood) 2008; 233:1527-36. [PMID: 18849544 DOI: 10.3181/0806-rm-197] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We recently described the discovery, genome, clinical features, genotypes and evolution of a novel and global human respiratory virus named human coronavirus HKU1 (HCoV-HKU1) which is not yet culturable. We expressed a C-terminal FLAG-tagged CoV-HKU1 spike (S) protein by the Semliki Forest Virus (SFV) system and investigated its maturation profile. Pulse chase labeling revealed that S-FLAG was expressed as high-mannose N-glycans of monomers and trimers. It was predominantly cleaved into subdomains S1 and S2 during maturation. S1 was secreted into the medium. Immunofluorescence analysis visualized S along the secretory pathway from endoplasmic reticulum to plasma membrane. Cleavage of S and release of HCoV-HKU1 S pseudotyped virus were inhibited by furin or furin-like enzyme inhibitors. The cell-based expressed full-length S-FLAG could be recognized by the convalescent serum obtained from a patient with HCoV-HKU1 pneumonia. The data suggest that the native form of HCoV-HKU1 spike expressed in our system can be used in developing serological diagnostic assay and in understanding the role of S in the viral life cycle.
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Affiliation(s)
- Che-Man Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administration Region, Hong Kong
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5
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Callendret B, Lorin V, Charneau P, Marianneau P, Contamin H, Betton JM, van der Werf S, Escriou N. Heterologous viral RNA export elements improve expression of severe acute respiratory syndrome (SARS) coronavirus spike protein and protective efficacy of DNA vaccines against SARS. Virology 2007; 363:288-302. [PMID: 17331558 PMCID: PMC7103356 DOI: 10.1016/j.virol.2007.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Revised: 12/19/2006] [Accepted: 01/15/2007] [Indexed: 01/19/2023]
Abstract
The SARS-CoV spike glycoprotein (S) is the main target of the protective immune response in humans and animal models of SARS. Here, we demonstrated that efficient expression of S from the wild-type spike gene in cultured cells required the use of improved plasmid vectors containing donor and acceptor splice sites, as well as heterologous viral RNA export elements, such as the CTE of Mazon-Pfizer monkey virus or the PRE of Woodchuck hepatitis virus (WPRE). The presence of both splice sites and WPRE markedly improved the immunogenicity of S-based DNA vaccines against SARS. Upon immunization of mice with low doses (2 microg) of naked DNA, only intron and WPRE-containing vectors could induce neutralizing anti-S antibodies and provide protection against challenge with SARS-CoV. Our observations are likely to be useful for the construction of plasmid and viral vectors designed for optimal expression of intronless genes derived from cytoplasmic RNA viruses.
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Affiliation(s)
- Benoît Callendret
- Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, EA 302 Université Paris 7, France
| | - Valérie Lorin
- Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, EA 302 Université Paris 7, France
| | - Pierre Charneau
- Groupe à 5 ans de Virologie Moléculaire et de Vectorologie, France
| | - Philippe Marianneau
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Hugues Contamin
- Unité de Biologie des Infections Virales Emergentes, Institut Pasteur, IFR 128 BioSciences Lyon-Gerland, 21 avenue Tony Garnier, 69365 Lyon Cedex 07, France
| | - Jean-Michel Betton
- Unité de Biochimie Structurale, URA CNRS 2185, Institut Pasteur, 25 rue du Dr. Roux, 75724 PARIS Cedex 15, France
| | - Sylvie van der Werf
- Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, EA 302 Université Paris 7, France
| | - Nicolas Escriou
- Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, EA 302 Université Paris 7, France
- Corresponding author. Unité de Génétique Moléculaire des Virus Respiratoires, URA CNRS 1966, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France. Fax: +33 140613241.
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6
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Perlman S, Holmes KV. Intracellular transport of the S proteins of coronaviruses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 581:271-5. [PMID: 17037541 PMCID: PMC7123658 DOI: 10.1007/978-0-387-33012-9_45] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Stanley Perlman
- Department of Pediatrics, University of Iowa, 52242 Iowa City, IA USA
| | - Kathryn V. Holmes
- Department of Microbiology, University of Colorado Health Sciences Center at Fitzsimons, 80045-8333 Aurora, CO USA
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Yin J, Ren X, Tian Z, Li Y. Assembly of pseudorabies virus genome-based transfer vehicle carrying major antigen sites of S gene of transmissible gastroenteritis virus: potential perspective for developing live vector vaccines. Biologicals 2006; 35:55-61. [PMID: 16731004 PMCID: PMC7128284 DOI: 10.1016/j.biologicals.2006.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 12/20/2005] [Accepted: 02/01/2006] [Indexed: 01/08/2023] Open
Abstract
Two severe porcine infectious diseases, pseudorabies (PR) and transmissible gastroenteritis (TGE) caused by pseudorabies virus (PRV) and transmissible gastroenteritis virus (TGEV) respectively often result in serious economic loss in animal husbandry worldwide. Vaccination is the important prevention means against both infections. To achieve a PRV genome-based virus live vector, aiming at further TGEV/PRV bivalent vaccine development, a recombinant plasmid pUG was constructed via inserting partial PK and full-length gG genes of PRV strain Bartha K-61 amplified into pUC119 vector. In parallel, another recombinant pHS was generated by introducing a fragment designated S1 encoding the major antigen sites of S gene from TGEV strain TH-98 into a prokaryotic expression vector pPROEX HTc. The SV40 polyA sequence was then inserted into the downstream of S1 fragment of pHS. The continuous region containing S1fragment, SV40 polyA and four single restriction enzyme sites digested from pHS was subcloned into the downstream of gG promoter of pUG. In addition, a LacZ reporter gene was introduced into the universal transfer vector named pUGS-LacZ. Subsequently, a PRV genome-based virus live vector was generated via homologous recombination. The functionally effective vector was purified and partially characterized. Moreover, the potential advantages of this system are discussed.
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Affiliation(s)
- Jiechao Yin
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, 59 Mucai Street, 150030 Harbin, PR China
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8
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Song HC, Seo MY, Stadler K, Yoo BJ, Choo QL, Coates SR, Uematsu Y, Harada T, Greer CE, Polo JM, Pileri P, Eickmann M, Rappuoli R, Abrignani S, Houghton M, Han JH. Synthesis and characterization of a native, oligomeric form of recombinant severe acute respiratory syndrome coronavirus spike glycoprotein. J Virol 2004; 78:10328-35. [PMID: 15367599 PMCID: PMC516425 DOI: 10.1128/jvi.78.19.10328-10335.2004] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have expressed and characterized the severe acute respiratory syndrome coronavirus (SARS-CoV) spike protein in cDNA-transfected mammalian cells. The full-length spike protein (S) was newly synthesized as an endoglycosidase H (endo H)-sensitive glycoprotein (gp170) that is further modified into an endo H-resistant glycoprotein (gp180) in the Golgi apparatus. No substantial proteolytic cleavage of S was observed, suggesting that S is not processed into head (S1) and stalk (S2) domains as observed for certain other coronaviruses. While the expressed full-length S glycoprotein was exclusively cell associated, a truncation of S by excluding the C-terminal transmembrane and cytoplasmic tail domains resulted in the expression of an endoplasmic reticulum-localized glycoprotein (gp160) as well as a Golgi-specific form (gp170) which was ultimately secreted into the cell culture medium. Chemical cross-linking, thermal denaturation, and size fractionation analyses suggested that the full-length S glycoprotein of SARS-CoV forms a higher order structure of approximately 500 kDa, which is consistent with it being an S homotrimer. The latter was also observed in purified virions. The intracellular form of the C-terminally truncated S protein (but not the secreted form) also forms trimers, but with much less efficiency than full-length S. Deglycosylation of the full-length homotrimer with peptide N-glycosidase-F under native conditions abolished recognition of the protein by virus-neutralizing antisera raised against purified virions, suggesting the importance of the carbohydrate in the correct folding of the S protein. These data should aid in the design of recombinant vaccine antigens to prevent the spread of this emerging pathogen.
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MESH Headings
- Animals
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- COS Cells
- Cell Line
- Chlorocebus aethiops
- Cricetinae
- Culture Media/chemistry
- DNA, Complementary
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Endoplasmic Reticulum/chemistry
- Glycoside Hydrolases/metabolism
- Golgi Apparatus/chemistry
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/metabolism
- Molecular Weight
- Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase/metabolism
- Protein Folding
- Protein Processing, Post-Translational
- Protein Structure, Tertiary
- Protein Subunits/analysis
- Protein Transport
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
- Severe acute respiratory syndrome-related coronavirus/genetics
- Spike Glycoprotein, Coronavirus
- Viral Envelope Proteins/chemistry
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
- Viral Envelope Proteins/metabolism
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Affiliation(s)
- Hyun Chul Song
- Vaccines Research, Chiron Corporation, 4560 Horton St., Emeryville, CA 94608, USA
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9
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Schwegmann-Wessels C, Al-Falah M, Escors D, Wang Z, Zimmer G, Deng H, Enjuanes L, Naim HY, Herrler G. A novel sorting signal for intracellular localization is present in the S protein of a porcine coronavirus but absent from severe acute respiratory syndrome-associated coronavirus. J Biol Chem 2004; 279:43661-6. [PMID: 15304515 PMCID: PMC8060824 DOI: 10.1074/jbc.m407233200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Coronaviruses (CoV) mature by a budding process at intracellular membranes. Here we showed that the major surface protein S of a porcine CoV (transmissible gastroenteritis virus) is not transported to the cell surface but is retained intracellularly. Site-directed mutagenesis indicated that a tyrosine-dependent signal (YXXI) in the cytoplasmic tail is essential for intracellular localization of the S protein. Surface expression of mutant proteins was evident by immunofluorescence analysis and surface biotinylation. Intracellularly retained S proteins only contained endoglycosidase H-sensitive N-glycans, whereas mutant proteins that migrated to the plasma membrane acquired N-linked oligosaccharides of the complex type. Corresponding tyrosine residues are present in the cytoplasmic tails of the S proteins of other animal CoV but not in the tail portion of the S protein of severe acute respiratory syndrome (SARS)-CoV. Changing the SEPV tetrapeptide in the cytoplasmic tail to YEPI resulted in intracellular retention of the S protein of SARS-CoV. As the S proteins of CoV have receptor binding and fusion activities and are the main target of neutralizing antibodies, the differences in the transport behavior of the S proteins suggest different strategies in the virus host interactions between SARS-CoV and other coronaviruses.
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10
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Liu C, Kokuho T, Kubota T, Watanabe S, Inumaru S, Yokomizo Y, Onodera T. DNA mediated immunization with encoding the nucleoprotein gene of porcine transmissible gastroenteritis virus. Virus Res 2001; 80:75-82. [PMID: 11597750 DOI: 10.1016/s0168-1702(01)00333-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The immune response to a naked plasmid DNA encoding the nucleoprotein (N protein) of porcine transmissible gastroenteritis virus (TGEV) was investigated in this study. A complementary DNA of the entire N gene was amplified by RT-PCR, and inserted into a mammalian expression vector (pcDNA3.1) to construct a recombinant plasmid (pcDNA/N). To evaluate the immunogenicity of the construct, BALB/c mice were intramuscularly immunized with different doses (50, 100 and 200 microg/mouse) of pcDNA/N twice at a 5-week interval. An optimal antibody response was achieved with 100 microg of pcDNA/N. The response lasted at least 11 weeks after primary immunization. By western blotting analysis, the antibodies specifically recognized a 47 kDa protein corresponding to the viral N protein, but they did not reveal neutralizing activity against infectious TGEV in vitro. Immunoglobulin G2a was predominant among these antibodies, which was indicative of Th1 type cell activation in pcDNA/N immunized mice. Moreover, spleen cells from these mice showed stronger immune responses than those from live vaccine or parental vector immunized mice. These results suggest that the construct can elicit both humoral and cell-mediated immune (CMI) responses against TGEV N protein in mice.
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Affiliation(s)
- C Liu
- National Institute of Animal Health, 3-1-1 Kannondai, Tsukuba, 305-0856, Ibaraki, Japan
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11
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Abstract
Friesian calves were infected with one of three isolates of bovine viral diarrhoea virus (BVDV) and used to establish parameters for an in vitro model of BVDV-reactive T-cell responses in cattle. The study assessed virus clearance, seroconversion, maturation of lymphoproliferative responses (both during and following disease resolution) and the antigen-specificity of CD4(+) T cells from recovered animals. Seroconversion and virus-specific lymphoproliferation were not detected until viraemia had resolved. Interestingly, lymphoproliferation was detected earlier in the animals infected with cytopathic viruses than in those infected with noncytopathic virus despite broadly similar rates of virus clearance and seroconversion for both biotypes. CD4(+) and CD8(+) T cells were induced to proliferate by virus-infected stimulator cells whereas only CD4(+) T cells responded to non-infectious antigens. Lymphoproliferation was strain cross-reactive and MHC-restricted. Induction of T-cell proliferation by recombinant proteins identified the major envelope proteins E(rns) and E2 and the nonstructural (NS) 2-3 protein as T-cell determinants. In addition, the capsid (C) and/or the amino-terminal proteinase, N(pro) were identified as T-cell determinants from the responses of short-term T-cell lines. Thus, in this model, the CD4(+) T-cell repertoire induce by acute BVDV infection includes at least the major envelope proteins, NS2-3, and capsid and/or N(pro).
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Affiliation(s)
- T Collen
- Division of Immunopathology, Institute for Animal Health, Compton, UK.
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12
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Sestak K, Meister RK, Hayes JR, Kim L, Lewis PA, Myers G, Saif LJ. Active immunity and T-cell populations in pigs intraperitoneally inoculated with baculovirus-expressed transmissible gastroenteritis virus structural proteins. Vet Immunol Immunopathol 1999; 70:203-21. [PMID: 10507362 PMCID: PMC7119614 DOI: 10.1016/s0165-2427(99)00074-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The intraperitoneal inoculation of pigs with baculovirus-expressed transmissible gastroenteritis virus (TGEV) structural proteins (S, N, M) in conjunction with thermolabile Escherichia coli mutant toxin (LT-R192G) in incomplete Freund's adjuvant (IFA) was tested in an attempt to elicit active immunity to TGEV in gut-associated lymphoid tissues (GALT). Four groups of 63 (1-5-week-old) suckling, TGEV-seronegative pigs were used to assess the efficacy of the recombinant protein vaccine (group 3) in comparison with sham (group 1), commercial vaccine (group 2), and virulent TGEV Miller-strain-inoculated pigs (group 4). The TGEV-specific mucosal and systemic immune responses were measured after in vivo and in vitro stimulation with TGEV-antigens. The major T-cell subset distribution was analyzed in vivo and in vitro after stimulation of mononuclear cells with TGEV (from mesenteric lymph nodes of group 3 inoculated with TGEV-recombinant proteins). Induction of active immunity was assessed by challenge of pigs with virulent TGEV at 27 days of age. Baculovirus-expressed TGEV proteins coadministered with LT-R192G in IFA induced mesenteric lymph node immune responses associated with IgA-antibodies to TGEV and partial protection against TGEV-challenge. The high titers of serum IgG- and virus-neutralizing-antibodies to TGEV in group 3 pigs most likely reflected the dose of TGEV S-protein administered. At the day of TGEV-challenge, the in vitro stimulation of mononuclear cells from the mesenteric lymph nodes of group 3 pigs with inactivated TGEV resulted in an increase in double positive (CD4+CD8+), natural killer (CD2+CD4-CD8+dim) and cytotoxic (CD2+CD4-CD8+bright) T-cell phenotypes, accompanied by increased expression of interleukin-2 receptor and a decrease of the null (CD2-CD4-CD8-/SW6+) cell phenotype.
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Affiliation(s)
- K Sestak
- Food Animal Health Research Program, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691, USA
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13
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Hiscox JA, Mawditt KL, Cavanagh D, Britton P. Investigation of the control of coronavirus subgenomic mRNA transcription by using T7-generated negative-sense RNA transcripts. J Virol 1995; 69:6219-27. [PMID: 7666523 PMCID: PMC189519 DOI: 10.1128/jvi.69.10.6219-6227.1995] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The subgenomic mRNAs of the coronavirus transmissible gastroenteritis virus (TGEV) are not produced in equimolar amounts. We have developed a reporter gene system to investigate the control of this differential subgenomic mRNA synthesis. Transcription of mRNAs by the TGEV polymerase was obtained from negative-sense RNA templates generated in situ from DNA containing a T7 promoter. A series of gene cassettes was produced; these cassettes comprised the reporter chloramphenicol acetyltransferase (CAT) gene downstream of transcription-associated sequences (TASs) (also referred to as intergenic sequences and promoters) believed to be involved in the synthesis of TGEV subgenomic mRNAs 6 and 7. The gene cassettes were designed so that negative-sense RNA copies of the CAT gene with sequences complementary to the TGEV TASs, or modified versions, at the 3' end would be synthesized in situ by T7 RNA polymerase. Using this system, we have demonstrated that CAT was expressed from mRNAs derived from the T7-generated negative-sense RNA transcripts only in TGEV-infected cells and only from transcripts possessing a TGEV negative-sense TAS. Analysis of the CAT mRNAs showed the presence of the TGEV leader RNA sequence at the 5' end, in keeping with observations that all coronavirus mRNAs have a 5' leader sequence corresponding to the 5' end of the genomic RNA. Our results indicated that the CAT mRNAs were transcribed from the in situ-synthesized negative-sense RNA templates without the requirement of TGEV genomic 5' or 3' sequences on the T7-generated negative-sense transcripts (3'-TAS-CAT-5'). Modification of the TGEV TASs indicated (i) that the degree of potential base pairing between the 3' end of the leader RNA and the TGEV negative-sense TAS was not the sole determinant of the amount of subgenomic mRNA transcribed and (ii) that other factors, including nucleotides flanking the TAS, are involved in the regulation of transcription of TGEV subgenomic mRNAs.
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Affiliation(s)
- J A Hiscox
- Division of Molecular Biology, Institute for Animal Health, Compton, Newbury, United Kingdom
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14
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Godet M, Grosclaude J, Delmas B, Laude H. Major receptor-binding and neutralization determinants are located within the same domain of the transmissible gastroenteritis virus (coronavirus) spike protein. J Virol 1994; 68:8008-16. [PMID: 7525985 PMCID: PMC237264 DOI: 10.1128/jvi.68.12.8008-8016.1994] [Citation(s) in RCA: 137] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The spike glycoprotein (S) of coronavirus, the major target for virus-neutralizing antibodies, is assumed to mediate the attachment of virions to the host cell. A 26-kilodalton fragment proteolytically cleaved from transmissible gastroenteritis virus (TGEV) S protein was previously shown to bear two adjacent antigenic sites, A and B, both defined by high-titer neutralizing antibodies. Recombinant baculoviruses expressing C-terminal truncations of the 26-kilodalton region were used to localize functionally important determinants in the S protein primary structure. Two overlapping 223- and 150-amino-acid-long products with serine 506 as a common N terminus expressed all of the site A and B epitopes and induced virus-binding antibodies. Coexpression of one of these truncated protein S derivatives with aminopeptidase N (APN), a cell surface molecule acting as a receptor for TGEV, led to the formation of a complex which could be immunoprecipitated by anti-S antibodies. These data provide evidence that major neutralization-mediating and receptor-binding determinants reside together within a domain of the S protein which behaves like an independent module. In spite of their ability to prevent S-APN interaction, the neutralizing antibodies appeared to recognize a preformed complex, thus indicating that antibody- and receptor-binding determinants should be essentially distinct. Together these findings bring new insight into the molecular mechanism of TGEV neutralization.
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Affiliation(s)
- M Godet
- Unité de Virologie et Immunologie Moléculaires, Institut National de la Recherche Agronomique, Jouy-en-Josas, France
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15
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Tuboly T, Nagy E, Dennis JR, Derbyshire JB. Immunogenicity of the S protein of transmissible gastroenteritis virus expressed in baculovirus. Arch Virol 1994; 137:55-67. [PMID: 7979998 PMCID: PMC7087137 DOI: 10.1007/bf01311173] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Seven fragments of the spike (S) gene cDNA of transmissible gastroenteritis virus (TGEV), as well as the full length cDNA, were cloned and expressed in baculovirus vectors. Piglets were immunized with cells infected with the recombinant viruses. Each of the recombinants induced TGEV-specific antibodies detected in a fixed cell enzyme immunoassay. The amino terminal half of the S protein, containing all four major antigenic sites (A, B, C and D), and encoded by a 2.2 kb fragment of the S gene, induced virus neutralizing (VN) antibody titers comparable with those induced by the complete S protein. Recombinant proteins lacking the A antigenic site, or with a deletion including the putative receptor binding sites and the D antigenic site, were not capable of inducing levels of VN antibodies similar to those induced by the whole S protein.
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Affiliation(s)
- T Tuboly
- Department of Veterinary Microbiology and Immunology, University of Guelph, Ontario, Canada
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16
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Olsen CW. A review of feline infectious peritonitis virus: molecular biology, immunopathogenesis, clinical aspects, and vaccination. Vet Microbiol 1993; 36:1-37. [PMID: 8236772 PMCID: PMC7117146 DOI: 10.1016/0378-1135(93)90126-r] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Feline infectious peritonitis (FIP) has been an elusive and frustrating problem for veterinary practitioners and cat breeders for many years. Over the last several years, reports have begun to elucidate aspects of the molecular biology of the causal virus (FIPV). These papers complement a rapidly growing base of knowledge concerning the molecular organization and replication of coronaviruses in general. The fascinating immunopathogenesis of FIPV infection and the virus' interaction with macrophages has also been the subject of several recent papers. It is now clear that FIPV may be of interest to scientists other than veterinary virologists since its pathogenesis may provide a useful model system for other viruses whose infectivity is enhanced in the presence of virus-specific antibody. With these advances and the recent release of the first commercially-available FIPV vaccine, it is appropriate to review what is known about the organization and replication of coronaviruses and the pathogenesis of FIPV infection.
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Affiliation(s)
- C W Olsen
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison
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