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Kalogianni AI, Bossis I, Ekateriniadou LV, Gelasakis AI. Etiology, Epizootiology and Control of Maedi-Visna in Dairy Sheep: A Review. Animals (Basel) 2020; 10:E616. [PMID: 32260101 PMCID: PMC7222820 DOI: 10.3390/ani10040616] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 01/04/2023] Open
Abstract
Maedi-visna (MV) in sheep is caused by maedi-visna virus (MVV), a small ruminant lentivirus (SRLV) that causes chronic infection and inflammatory lesions in infected animals. Pneumonia and mastitis are its predominant clinical manifestations, and the tissues infected by MVV are mainly the lungs, the mammary gland, the nervous system and the joints. MV has a worldwide distribution with distinct MVV transmission patterns depending on circulating strains and regionally applied control/eradication schemes. Nevertheless, the prevalence rate of MV universally increases. Currently, gaps in understanding the epizootiology of MV, the continuous mutation of existing and the emergence of new small ruminant lentiviruses (SRLVs) strains, lack of an effective detection protocol and the inefficiency of currently applied preventive measures render elimination of MV an unrealistic target. Therefore, modifications on the existing MV surveillance and control schemes on an evidentiary basis are necessary. Updated control schemes require the development of diagnostic protocols for the early and definitive diagnosis of MVV infections. The objectives of this review are to summarize the current knowledge in the epizootiology and control of MV in dairy sheep, to describe the research framework and to cover existing gaps in understanding future challenges regarding MV.
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Affiliation(s)
- Aphrodite I Kalogianni
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
| | - Ioannis Bossis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
| | | | - Athanasios I Gelasakis
- Laboratory of Anatomy and Physiology of Farm Animals, Department of Animal Science, Agricultural University of Athens (AUA), Iera Odos 75 str., 11855 Athens, Greece
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2
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Blacklaws BA. Small ruminant lentiviruses: immunopathogenesis of visna-maedi and caprine arthritis and encephalitis virus. Comp Immunol Microbiol Infect Dis 2012; 35:259-69. [PMID: 22237012 DOI: 10.1016/j.cimid.2011.12.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
Abstract
The small ruminant lentiviruses include the prototype for the genus, visna-maedi virus (VMV) as well as caprine arthritis encephalitis virus (CAEV). Infection of sheep or goats with these viruses causes slow, progressive, inflammatory pathology in many tissues, but the most common clinical signs result from pathology in the lung, mammary gland, central nervous system and joints. This review examines replication, immunity to and pathogenesis of these viruses and highlights major differences from and similarities to some of the other lentiviruses.
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Affiliation(s)
- Barbara A Blacklaws
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK.
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3
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Reina R, Barbezange C, Niesalla H, de Andrés X, Arnarson H, Biescas E, Mazzei M, Fraisier C, McNeilly TN, Liu C, Perez M, Carrozza ML, Bandecchi P, Solano C, Crespo H, Glaria I, Huard C, Shaw DJ, de Blas I, de Andrés D, Tolari F, Rosati S, Suzan-Monti M, Andrésdottir V, Torsteinsdottir S, Petursson G, Lujan L, Pepin M, Amorena B, Blacklaws B, Harkiss GD. Mucosal immunization against ovine lentivirus using PEI-DNA complexes and modified vaccinia Ankara encoding the gag and/or env genes. Vaccine 2008; 26:4494-505. [PMID: 18606204 DOI: 10.1016/j.vaccine.2008.06.065] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 06/04/2008] [Accepted: 06/13/2008] [Indexed: 11/25/2022]
Abstract
Sheep were immunized against Visna/Maedi virus (VMV) gag and/or env genes via the nasopharynx-associated lymphoid tissue (NALT) and lung using polyethylenimine (PEI)-DNA complexes and modified vaccinia Ankara, and challenged with live virus via the lung. env immunization enhanced humoral responses prior to but not after VMV challenge. Systemic T cell proliferative and cytotoxic responses were generally low, with the responses following single gag gene immunization being significantly depressed after challenge. A transient reduction in provirus load in the blood early after challenge was observed following env immunization, whilst the gag gene either alone or in combination with env resulted in significantly elevated provirus loads in lung. However, despite this, a significant reduction in lesion score was observed in animals immunized with the single gag gene at post-mortem. Inclusion of IFN-gamma in the immunization mixture in general had no significant effects. The results thus showed that protective effects against VMV-induced lesions can be induced following respiratory immunization with the single gag gene, though this was accompanied by an increased pulmonary provirus load.
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Affiliation(s)
- R Reina
- CSIC-Public University of Navarra, Pamplona, Spain
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4
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Abstract
The lesions caused by maedi-visna virus (MVV) are known to be immune mediated with a presumed contribution by the response to viral antigens. However, very little is known about the T-cell response to individual viral proteins. We have therefore expressed the three individual gag antigens of MVV strain EV1 (p16, p25, and p14) in a bacterial expression system and used the purified recombinant proteins to analyze the antibody and CD4+ T-cell response to MVV. Plasma samples were taken from sheep after 1 year of infection with MVV. The titers for antibodies in these samples were determined by indirect enzyme-linked immunosorbent assays and were as follows: anti-p25 antibody, 1:400 to >1:3,200; anti-p16 antibody, 1:400 to 1:3,200; and anti-p14 antibody, 1:<100 to 1:3,200. When the induction of antibodies was followed over time postinfection (p.i.), samples positive for anti-p25 were seen by day 24 p.i., followed by anti-p16 by day 45 p.i., and lastly anti-p14 by day 100 p.i. T-cell proliferative responses to all three gag antigens were detected in persistently infected sheep peripheral blood lymphocytes. The antigens were therefore used to raise T-cell lines from persistently infected sheep. These T-cell lines were shown to be specific for the recombinant gag antigens and for viral antigen expressed on infected macrophages. The proliferative response was restricted to major histocompatibility complex class II HLA-DR and so was due to CD4+ T lymphocytes. All three gag antigens may therefore play a role in immune-mediated lesion formation in MVV disease by presentation on infected macrophages in lesions.
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Affiliation(s)
- Inderpal Singh
- Centre for Veterinary Science, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, United Kingdom CB3 0ES
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5
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Trujillo JD, Hötzel KJ, Snekvik KR, Cheevers WP. Antibody response to the surface envelope of caprine arthritis-encephalitis lentivirus: disease status is predicted by SU antibody isotype. Virology 2004; 325:129-36. [PMID: 15231392 DOI: 10.1016/j.virol.2004.03.048] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2003] [Revised: 01/16/2004] [Accepted: 03/29/2004] [Indexed: 11/16/2022]
Abstract
This study evaluated the hypothesis that the disease status of Saanen goats infected with caprine arthritis-encephalitis lentivirus (CAEV) is associated with the focus of immune responses to viral antigens, particularly the surface envelope glycoprotein (SU). Specifically, we have proposed that Th2 responses promote progressive immune-mediated arthritis, whereas Th1 responses restrict virus replication and development of clinical disease. The present study determined the isotype of SU antibodies associated with progressor and long-term nonprogressor (LTNP) status. We show that chronically infected goats that develop clinical arthritis have predominantly IgG1 antibodies to SU during both preclinical and clinical stages of disease, whereas SU antibodies of LTNP goats are relatively biased toward IgG2. Additional studies determined the isotype of SU antibodies induced initially by CAEV infection. These experiments show that initial IgG1-dominated responses to SU are associated with subsequent development of preclinical inflammatory joint lesions, whereas lack of joint pathology is associated with an IgG2 bias of initial responses to SU. Our results using the CAEV model suggest that isotype bias of SU antibodies is a reliable indicator of clinical disease caused by lentiviruses. Isotype analysis may be a useful method to screen candidate lentiviral vaccines intended to prevent disease progression.
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Affiliation(s)
- Jessie D Trujillo
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
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6
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Cheevers WP, Snekvik KR, Trujillo JD, Kumpula-McWhirter NM, Pretty On Top KJ, Knowles DP. Prime-boost vaccination with plasmid DNA encoding caprine-arthritis encephalitis lentivirus env and viral SU suppresses challenge virus and development of arthritis. Virology 2003; 306:116-25. [PMID: 12620804 DOI: 10.1016/s0042-6822(02)00044-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study evaluated the efficacy of prime-boost vaccination for immune control of caprine arthritis-encephalitis virus (CAEV), a macrophage tropic lentivirus that causes progressive arthritis in the natural host. Vaccination of Saanen goats with pUC-based plasmid DNA expressing CAEV env induces T helper type 1 (Th1) biased immune responses to vector-encoded surface envelope (SU), and the plasmid-primed Th1 response is expanded following boost with purified SU in Freund's incomplete adjuvant (SU-FIA) (J. C. Beyer et al., 2001, Vaccine 19, 1643-1651). Four goats vaccinated with env expression plasmids and boosted with SU-FIA were challenged intravenously with 1 x 10(4) TCID(50) of CAEV at 428 days after SU-FIA boost and evaluated by immunological, virological, and disease criteria. Controls included two goats primed with pUC18 and eight unvaccinated goats. Goats receiving prime-boost vaccination with CAEV env plasmids and SU-FIA became infected but suppressed postchallenge virus replication, provirus loads in lymph node, and development of arthritis for at least 84 weeks.
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Affiliation(s)
- W P Cheevers
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164, USA.
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7
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Beyer JC, Chebloune Y, Mselli-Lakhal L, Hötzel I, Kumpula-McWhirter N, Cheevers WP. Immunization with plasmid DNA expressing the caprine arthritis-encephalitis virus envelope gene: quantitative and qualitative aspects of antibody response to viral surface glycoprotein. Vaccine 2001; 19:1643-51. [PMID: 11166887 DOI: 10.1016/s0264-410x(00)00418-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Saanen goats were vaccinated intradermally with plasmid DNA expressing caprine arthritis-encephalitis virus (CAEV) rev-env (pENV) or tat-rev-env (pTAT-ENV) or vaccinia virus expressing CAEV env (rWR-63). Sera from all vaccinated goats immunoprecipitated CAEV surface (SU) and transmembrane (TM) glycoproteins with a dominant response to SU. Antibody response to CAEV SU induced by plasmid DNA was relatively biased toward IgG2, whereas vaccinia rWR-63 induced predominantly IgG1 antibodies to SU. Differential IgG isotype bias established by immunization with plasmid or vaccinia vectors was maintained following subcutaneous boost with purified CAEV SU in Freund's incomplete adjuvant (FIA). Goats injected with pUC18 control plasmid followed by immunization with SU-FIA also had IgG2 biased responses, whereas SU-FIA immunization of a goat primed with vaccinia rWR-SC11 without the CAEV env gene induced a predominant IgG1 response. We conclude that pUC based plasmids expressing the CAEV env gene promote stable type 1 biased immune responses to plasmid encoded SU. IgG2 biased response may be due to innate type 1 priming capacity of immunostimulatory CpG motifs in the pUC ampicillin resistance gene.
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MESH Headings
- Animals
- Antibodies, Viral/immunology
- Arthritis-Encephalitis Virus, Caprine/genetics
- Arthritis-Encephalitis Virus, Caprine/immunology
- COS Cells
- Gene Products, env/chemistry
- Gene Products, env/genetics
- Gene Products, env/immunology
- Gene Products, tat/genetics
- Genetic Vectors/genetics
- Glycoproteins
- Goats/immunology
- Immunization, Secondary
- Immunoglobulin G/immunology
- Immunoglobulin Isotypes/immunology
- Membrane Proteins
- Plasmids/genetics
- RNA, Messenger/analysis
- RNA, Messenger/genetics
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Reverse Transcriptase Polymerase Chain Reaction
- Vaccination
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- Vaccinia virus/genetics
- Viral Proteins
- Viral Vaccines/genetics
- Viral Vaccines/immunology
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Affiliation(s)
- J C Beyer
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA
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8
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Bertoni G, Hertig C, Zahno ML, Vogt HR, Dufour S, Cordano P, Peterhans E, Cheevers WP, Sonigo P, Pancino G. B-cell epitopes of the envelope glycoprotein of caprine arthritis-encephalitis virus and antibody response in infected goats. J Gen Virol 2000; 81:2929-2940. [PMID: 11086124 DOI: 10.1099/0022-1317-81-12-2929] [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: 11/18/2022] Open
Abstract
Goats infected with caprine arthritis-encephalitis virus (CAEV) develop high titres of antibodies to Env. Not only is no consistent neutralizing response found but anti-Env antibodies have even been associated with disease in infected goats. To identify the continuous antigenic determinants involved in this atypical anti-Env response, we mapped CAEV-CO Env by screening an epitope expression library with infected goat sera. In addition to the four previously described epitopes, seven novel antigenic sites were identified, of which five were located on the surface (SU) and two in the transmembrane (TM) subunits of Env. The SU antibody-binding domains located in the variable regions of the C-terminal part of the molecule (SU3 to SU5) showed the strongest reactivity and induced a rapid seroconversion in six experimentally infected goats. However, the response to these immunodominant epitopes did not appear to be associated with any neutralizing activity. The pattern of serum reactivity of naturally infected goats with these epitopes was restricted, suggesting a type-specific reaction. Interestingly, the reactivity of peptides representing SU5 sequences derived from CAEV field isolates varied with the geographical and/or breeding origin of the animals. This suggests that peptides corresponding to the immunodominant SU epitopes may well be useful in the serotyping of CAEV isolates. Furthermore, the identification of the CAEV Env epitopes will permit us to functionally dissect the antibody response and to address the role of anti-Env antibodies either in the protection from or in the pathogenesis of CAEV infection.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/immunology
- Antibody Specificity
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Arthritis-Encephalitis Virus, Caprine/chemistry
- Arthritis-Encephalitis Virus, Caprine/genetics
- Arthritis-Encephalitis Virus, Caprine/immunology
- Arthritis-Encephalitis Virus, Caprine/physiology
- Binding Sites
- Blotting, Western
- Cloning, Molecular
- Epitope Mapping
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/genetics
- Epitopes, B-Lymphocyte/immunology
- Gene Products, env/chemistry
- Gene Products, env/genetics
- Gene Products, env/immunology
- Glycoproteins
- Goats/immunology
- Goats/virology
- Immune Sera/biosynthesis
- Immune Sera/immunology
- Immunodominant Epitopes/chemistry
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/immunology
- Lentivirus Infections/immunology
- Lentivirus Infections/veterinary
- Membrane Proteins
- Molecular Sequence Data
- Neutralization Tests
- Peptide Library
- Protein Structure, Tertiary
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Sequence Alignment
- Time Factors
- Viral Proteins
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Affiliation(s)
- Giuseppe Bertoni
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Christian Hertig
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Marie-Luise Zahno
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Hans-Rudolf Vogt
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Sophie Dufour
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Pablo Cordano
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - Ernst Peterhans
- Institute of Veterinary Virology, University of Berne, Länggass-Str. 122, CH-3012 Berne, Switzerland1
| | - William P Cheevers
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington 99164-7040, USA2
| | - Pierre Sonigo
- Génétique des Virus (ICGM-CNRS UPR 0415), Institut Cochin de Génétique moléculaire, 75014 Paris, France3
| | - Gianfranco Pancino
- Génétique des Virus (ICGM-CNRS UPR 0415), Institut Cochin de Génétique moléculaire, 75014 Paris, France3
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9
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Cheevers WP, Hötzel I, Beyer JC, Kumpula-McWhirter N. Immune response to caprine arthritis-encephalitis virus surface protein induced by coimmunization with recombinant vaccinia viruses expressing the caprine arthritis-encephalitis virus envelope gene and caprine interleukin-12. Vaccine 2000; 18:2494-503. [PMID: 10775783 DOI: 10.1016/s0264-410x(00)00043-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objective of this study was to determine if interleukin (IL)-12 can focus an antigen specific type 1 immune response characterized by activation of Th1 lymphocytes and production of IgG2 antibodies in vivo. Saanen goats co-immunized with recombinant vaccinia viruses expressing caprine IL-12 (rRB-IL12) and the caprine arthritis-encephalitis virus (CAEV) envelope (env) gene (rWR-63) were evaluated for development of immune responses to the CAEV env encoded surface glycoprotein (SU). Immune responses were defined by: (i) SU antibody titers; (ii) the ratio of SU IgG1 and IgG2 antibodies; (iii) interferon gamma (IFNgamma) and IL-4 gene expression and proliferative response of SU stimulated lymph node mononuclear cells (LNMC). Apart from enhancement of IFNgamma and IL-4 gene expression in SU stimulated LNMC, rRB-IL12 did not affect the immune response to rWR-63 encoded SU. Thus, localized production of exogenous species specific IL-12 at the site of immunization did not focus initial priming of antigen reactive Th lymphocytes. These results are in contrast to previous studies using inbred mice and raise questions regarding the use of cytokine adjuvants to focus immune responses in outbred animals.
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Affiliation(s)
- W P Cheevers
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164-7040, USA.
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10
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Kemp RK, Knowles DP, Perry LL, McGuire TC, Besser TE, Cheevers WP. Crossreactive neutralizing antibodies induced by immunization with caprine arthritis-encephalitis virus surface glycoprotein. Vaccine 2000; 18:1282-7. [PMID: 10649630 DOI: 10.1016/s0264-410x(99)00181-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four Saanen goats were immunized with affinity purified gp135 surface glycoprotein (SU) of caprine arthritis-encephalitis virus isolate 79-63 (CAEV-63) and evaluated for homologous and crossreactive serum neutralizing antibodies. CAEV-63 neutralizing antibodies were detected in all goats after seven immunizations with SU in Quil A adjuvant. Sera from three goats neutralized an independent CAEV isolate (CAEV-Co). However, serum from one goat did not detectably neutralize heterologous CAEV-Co and inhibited CAEV-Co neutralization by another serum.
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Affiliation(s)
- R K Kemp
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA
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11
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Rafnar B, Tobin GJ, Nagashima K, Gonda MA, Gunnarsson E, Andrésson OS, Georgsson G, Torsteinsdóttir S. Immune response to recombinant visna virus Gag and Env precursor proteins synthesized in insect cells. Virus Res 1998; 53:107-20. [PMID: 9620203 DOI: 10.1016/s0168-1702(97)00141-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Two different recombinant visna virus (VV) gag-baculoviruses were constructed for the expression of precursor VV Gag in insect cells. Both recombinant Gag viruses expressed proteins migrating on SDS PAGE at the predicted rate for VV Gag precursor, Pr50gag. However, differences were seen in the morphology of the virus-like particles produced. Monoclonal antibody directed against the VV Gag capsid protein (p25) and sera from sheep infected with ovine lentiviruses reacted to both 50-kDa proteins. A recombinant VV env-baculovirus was constructed, substituting sequences encoding the signal peptide of VV Env with the murine IFN-gamma analogue. Sera from ovine lentivirus infected sheep reacted in immunoblots with two proteins of approximately 100 and 200 kDa found in the plasma membrane of insect cells infected with env-recombinant virus. Sheep immunized with either the recombinant Gag or the Env proteins developed high antibody titers to VV in ELISA. The serum of sheep and ascitic fluid of mice immunized with the recombinant Gag reacted with native Pr50gag and the processed Gag proteins in immunoblots, whereas serum of the recombinant Env immunized sheep reacted with VV gp135 and a putative oligomer of gp135. The immunized sheep responded specifically to visna virus by lymphocyte proliferation in vitro.
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Affiliation(s)
- B Rafnar
- Institute for Experimental Pathology, University of Iceland, Reykjavik
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12
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Davies JM, Robinson WF, Carnegie PR. Antibody reactivity to the transmembrane protein of the caprine arthritis encephalitis virus correlates with severity of arthritis: no evidence for the involvement of epitope mimicry. Vet Immunol Immunopathol 1997; 60:131-47. [PMID: 9533272 DOI: 10.1016/s0165-2427(97)00095-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Serum and synovial antibody reactivities of caprine arthritis encephalitis virus (CAEV) infected goats were assessed by Western blotting against purified CAEV antigen and the greatest intensity of reactivity in the serum of arthritic goats was to the gp45 transmembrane protein (TM). The extracytoplasmic domain of the TM gene was cloned into a pGEX vector and expressed in Escherichia coli as a glutathione S transferase fusion protein (GST-TM). This clone was found to be 90.5 and 89.2% homologous to published sequences of CAEV TM gene. Serum of 16 goats naturally infected with CAEV were examined by Western blotting for reactivity to the fusion protein. Antibody reactivity to the GST-TM correlated with clinically detectable arthritis (R = 0.642, P < or = 0.007). The hypothesis that the immune response to the envelope proteins of the CAEV contributes to the severity of arthritis in goats naturally infected with CAEV via epitope mimicry was tested. Antibodies from 5 CAEV infected goats were affinity purified against the GST-TM fusion protein and tested for cross-reactivity with a series of goat synovial extracts and proteogylcans. No serum antibody response or cross-reactivity of affinity purified antibodies could be detected. Peptides of the CAEV SU that were predicted to be linear epitopes and a similar heat shock protein 83 (HSP) peptide identified by database searching, were synthesized and tested for reactivity in CAEV goats using ELISA, in vitro lymphocyte proliferation and delayed type hypersensitivity (DTH) assays. Peripheral blood lymphocytes from 10 of 17 goats with long term natural CAEV infections proliferated in vitro in response to CAEV and in vivo 3 of 7 CAEV infected goats had a DTH reaction to CAEV antigen. However, none of the peptides elicited significant cell mediated immune responses from CAEV infected goats. No antibody reactivity to the SU peptides or HSP peptide was found. We observed that the antibody reactivity to the CAEV TM protein associated with severity of arthritis however epitope mimicry by the envelope proteins of CAEV is unlikely to be involved.
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Affiliation(s)
- J M Davies
- Biotechnology Research Group, Murdoch University, Australia
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13
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Rowe JD, East NE. Risk factors for transmission and methods for control of caprine arthritis-encephalitis virus infection. Vet Clin North Am Food Anim Pract 1997; 13:35-53. [PMID: 9071745 DOI: 10.1016/s0749-0720(15)30363-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The major route of transmission of caprine-encephalitis virus (CAEV) is through the ingestion of CAEV-infected colostrum or milk. Less efficient routes of transmission are associated with prolonged contact with infected goats and are reviewed in this article. Prevention of CAEV is based on the removal of kids from their dam at birth, and feeding the kids heat-treated colostrum and pasteurized milk until weaning. Serologic testing and segregation or culling of seropositive goats is necessary to minimize horizontal transmission of CAEV.
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Affiliation(s)
- J D Rowe
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, USA
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14
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Knowles DP. Laboratory diagnostic tests for retrovirus infections of small ruminants. Vet Clin North Am Food Anim Pract 1997; 13:1-11. [PMID: 9071743 DOI: 10.1016/s0749-0720(15)30361-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The most practical and reliable approach to confirming a diagnosis of OPPV or CAEV infection is a combination of serology and clinical evaluation. Although serology represents the most cost effective method of diagnosing persistently infected, clinically normal animals, testing errors occur; the frequency of error depends on the performance data of the particular serologic assay being used. When PCR detection of OPPV and CAEV becomes routinely available, this detection method can be used in rigorous eradication programs to determine the infection status of animals that cannot be definitively diagnosed by serology. The important aspects of OPPV and CAEV infection that must be considered in designing programs to prevent transmission are (1) OPPV and CAEV persist for life in the infected host, (2) a major route of transmission is to lambs and kids via colostrum and milk during nursing, (3) contact transmission among adults can occur, and (4) time variability can exist among individual sheep and goats from infection to the appearance of detectable antibodies.
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MESH Headings
- Animals
- Arthritis-Encephalitis Virus, Caprine/genetics
- Arthritis-Encephalitis Virus, Caprine/immunology
- Arthritis-Encephalitis Virus, Caprine/isolation & purification
- DNA, Viral/analysis
- DNA, Viral/genetics
- Diagnostic Tests, Routine/methods
- Diagnostic Tests, Routine/veterinary
- Goat Diseases/blood
- Goat Diseases/diagnosis
- Goat Diseases/virology
- Goats
- Lentivirus Infections/blood
- Lentivirus Infections/diagnosis
- Lentivirus Infections/veterinary
- Pneumonia, Progressive Interstitial, of Sheep/blood
- Pneumonia, Progressive Interstitial, of Sheep/diagnosis
- Pneumonia, Progressive Interstitial, of Sheep/virology
- Retroviridae/genetics
- Retroviridae/immunology
- Retroviridae/isolation & purification
- Retroviridae Infections/blood
- Retroviridae Infections/diagnosis
- Retroviridae Infections/veterinary
- Sheep
- Sheep Diseases/blood
- Sheep Diseases/diagnosis
- Sheep Diseases/virology
- Visna-maedi virus/genetics
- Visna-maedi virus/immunology
- Visna-maedi virus/isolation & purification
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Affiliation(s)
- D P Knowles
- Animal Disease Research Unit, United States Department of Agriculture, Pullman, Washington, USA
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15
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Perk K, Yaniv A, Gazit A, Demartini JC. Evaluation of vaccines for ovine lentivirus infection. AIDS Res Hum Retroviruses 1996; 12:425-6. [PMID: 8882325 DOI: 10.1089/aid.1996.12.425] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- K Perk
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Israel
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