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Hull-Nye D, Meadows T, Smith? SR, Schwartz EJ. Key Factors and Parameter Ranges for Immune Control of Equine Infectious Anemia Virus Infection. Viruses 2023; 15:v15030691. [PMID: 36992401 PMCID: PMC10058099 DOI: 10.3390/v15030691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 02/28/2023] [Accepted: 03/03/2023] [Indexed: 03/09/2023] Open
Abstract
Equine Infectious Anemia Virus (EIAV) is an important infection in equids, and its similarity to HIV creates hope for a potential vaccine. We analyze a within-host model of EIAV infection with antibody and cytotoxic T lymphocyte (CTL) responses. In this model, the stability of the biologically relevant endemic equilibrium, characterized by the coexistence of long-term antibody and CTL levels, relies upon a balance between CTL and antibody growth rates, which is needed to ensure persistent CTL levels. We determine the model parameter ranges at which CTL and antibody proliferation rates are simultaneously most influential in leading the system towards coexistence and can be used to derive a mathematical relationship between CTL and antibody production rates to explore the bifurcation curve that leads to coexistence. We employ Latin hypercube sampling and least squares to find the parameter ranges that equally divide the endemic and boundary equilibria. We then examine this relationship numerically via a local sensitivity analysis of the parameters. Our analysis is consistent with previous results showing that an intervention (such as a vaccine) intended to control a persistent viral infection with both immune responses should moderate the antibody response to allow for stimulation of the CTL response. Finally, we show that the CTL production rate can entirely determine the long-term outcome, regardless of the effect of other parameters, and we provide the conditions for this result in terms of the identified ranges for all model parameters.
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Affiliation(s)
- Dylan Hull-Nye
- Department of Mathematics, Washington State University, Pullman, WA 99164, USA
| | - Tyler Meadows
- Department of Mathematics and Statistics, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Stacey R. Smith?
- Department of Mathematics, Faculty of Medicine, The University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Elissa J. Schwartz
- Department of Mathematics and Statistics, School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
- Correspondence:
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2
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On the irrationality of rational design of an HIV vaccine in light of protein intrinsic disorder. Arch Virol 2021; 166:1283-1296. [PMID: 33606110 PMCID: PMC7892713 DOI: 10.1007/s00705-021-04984-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/19/2020] [Indexed: 12/18/2022]
Abstract
The lack of progress in finding an efficient vaccine for a human immunodeficiency virus (HIV) is daunting. In fact, this search has spanned nearly four decades without much success. There are several objective reasons for such a failure, which include the highly glycosylated nature of HIV-1, the presence of neotopes, and high mutation rates. This article argues that the presence of highly flexible and intrinsically disordered regions in both human anti-HIV-1 antibodies and the major HIV-1immunogen, its surface glycoprotein gp120, represent one of the major causes for the lack of success in utilization of structure-based reverse vaccinology.
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Goh GKM, Uversky VN. Shell disorder and the HIV vaccine mystery: lessons from the legendary Oswald Avery. J Biomol Struct Dyn 2021; 40:5702-5711. [PMID: 33410379 DOI: 10.1080/07391102.2020.1870562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The search for a human immunodeficiency virus (HIV) vaccine has spanned nearly four decades without much success. A much needed paradigm shift can be found in the abnormally high levels of intrinsic disorder in the outer shells of HIVs, the hepatitis C virus (HCV), and herpes simplex viruses (HSVs), for which successful vaccines have not been established. On the other hand, this feature (high levels of intrinsic disorder in the outer shells) is completely absent in classic viruses for which effective vaccines are found, such as the rabies virus. The motions arising from the disordered outer shell result in the inability of antibodies to bind tightly to the polysaccharides on the viral surface proteins, and, therefore, induce inadequate immune response. Experiments conducted by the legendary Avery Oswald in the 1920s form the theoretical underpinning of this new model. Failures of the vaccines based on the HIV glycoprotein Gp120 and other vaccines can be traced back to the lack of understanding of the important roles of shell disorder in a "Trojan-horse" immune evasion mechanism utilized by the virus.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Laboratory of New Methods in Biology, Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Pushchino, Russia Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Russia
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4
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Ahmad I, Li S, Li R, Chai Q, Zhang L, Wang B, Yu C, Zheng YH. The retroviral accessory proteins S2, Nef, and glycoMA use similar mechanisms for antagonizing the host restriction factor SERINC5. J Biol Chem 2019; 294:7013-7024. [PMID: 30862674 DOI: 10.1074/jbc.ra119.007662] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/06/2019] [Indexed: 12/13/2022] Open
Abstract
Serine incorporator 5 (SERINC5) is a recently identified restriction factor that blocks virus entry but is antagonized by three unrelated retroviral accessory proteins. The S2 protein from equine infectious anemia virus (EIAV) has been reported to reduce SERINC5 expression at steady-state levels likely via the endocytic pathway; however, the precise mechanism is still unclear. Here, we investigated how EIAV S2 protein down-regulates SERINC5 compared with down-regulation induced by Nef from HIV-1 and glycoMA proteins from murine leukemia virus (MLV). Using bimolecular fluorescence complementation (BiFC) assay and immunoprecipitation (IP), we detected an interaction between S2 and SERINC5. We found that this interaction relies on the S2 myristoylation site, indicating that it may occur on the plasma membrane. S2 internalized SERINC5 via receptor-mediated endocytosis and targeted it to endosomes and lysosomes, resulting in a ubiquitination-dependent decrease in SERINC5 expression at steady-state levels. Both BiFC and IP detected a glycoMA-SERINC5 interaction, but a Nef-SERINC5 interaction was detected only by BiFC. Moreover, S2 and glycoMA down-regulated SERINC5 more effectively than did Nef. We further show that unlike Nef, both S2 and glycoMA effectively down-regulate SERINC2 and also SERINC5 from Xenopus tropicalis (xSERINC5). Moreover, we detected expression of the equine SERINC5 (eSERINC5) protein and observed that its expression is much weaker than expression levels of SERINC5 from other species. Nonetheless, eSERINC5 had a strong antiviral activity that was effectively counteracted by S2. We conclude that HIV-1, EIAV, and MLV share a similar mechanism to antagonize viral restriction by host SERINC5.
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Affiliation(s)
- Iqbal Ahmad
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Sunan Li
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Rongrong Li
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Qingqing Chai
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
| | - Lixin Zhang
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Bin Wang
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Changqing Yu
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and
| | - Yong-Hui Zheng
- From the Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Harbin 150069, China and .,Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan 48824
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5
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de Pablo-Maiso L, Doménech A, Echeverría I, Gómez-Arrebola C, de Andrés D, Rosati S, Gómez-Lucia E, Reina R. Prospects in Innate Immune Responses as Potential Control Strategies against Non-Primate Lentiviruses. Viruses 2018; 10:v10080435. [PMID: 30126090 PMCID: PMC6116218 DOI: 10.3390/v10080435] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/08/2018] [Accepted: 08/10/2018] [Indexed: 02/06/2023] Open
Abstract
Lentiviruses are infectious agents of a number of animal species, including sheep, goats, horses, monkeys, cows, and cats, in addition to humans. As in the human case, the host immune response fails to control the establishment of chronic persistent infection that finally leads to a specific disease development. Despite intensive research on the development of lentivirus vaccines, it is still not clear which immune responses can protect against infection. Viral mutations resulting in escape from T-cell or antibody-mediated responses are the basis of the immune failure to control the infection. The innate immune response provides the first line of defense against viral infections in an antigen-independent manner. Antiviral innate responses are conducted by dendritic cells, macrophages, and natural killer cells, often targeted by lentiviruses, and intrinsic antiviral mechanisms exerted by all cells. Intrinsic responses depend on the recognition of the viral pathogen-associated molecular patterns (PAMPs) by pathogen recognition receptors (PRRs), and the signaling cascades leading to an antiviral state by inducing the expression of antiviral proteins, including restriction factors. This review describes the latest advances on innate immunity related to the infection by animal lentiviruses, centered on small ruminant lentiviruses (SRLV), equine infectious anemia virus (EIAV), and feline (FIV) and bovine immunodeficiency viruses (BIV), specifically focusing on the antiviral role of the major restriction factors described thus far.
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MESH Headings
- Animals
- Cats
- Cattle
- Dendritic Cells/immunology
- Dendritic Cells/virology
- Gene Expression Regulation/immunology
- Goats
- Horses
- Immunity, Innate
- Immunodeficiency Virus, Bovine/immunology
- Immunodeficiency Virus, Bovine/pathogenicity
- Immunodeficiency Virus, Feline/immunology
- Immunodeficiency Virus, Feline/pathogenicity
- Infectious Anemia Virus, Equine/immunology
- Infectious Anemia Virus, Equine/pathogenicity
- Interferon Regulatory Factors/genetics
- Interferon Regulatory Factors/immunology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/virology
- Lentivirus Infections/genetics
- Lentivirus Infections/immunology
- Lentivirus Infections/virology
- Macrophages/immunology
- Macrophages/virology
- Pathogen-Associated Molecular Pattern Molecules/immunology
- Receptors, Pattern Recognition/genetics
- Receptors, Pattern Recognition/immunology
- Sheep
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
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Affiliation(s)
- Lorena de Pablo-Maiso
- Instituto de Agrobiotecnología (IdAB), UPNA-CSIC-Gobierno de Navarra, Navarra 31192, Spain.
| | - Ana Doménech
- Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain.
| | - Irache Echeverría
- Instituto de Agrobiotecnología (IdAB), UPNA-CSIC-Gobierno de Navarra, Navarra 31192, Spain.
| | - Carmen Gómez-Arrebola
- Instituto de Agrobiotecnología (IdAB), UPNA-CSIC-Gobierno de Navarra, Navarra 31192, Spain.
| | - Damián de Andrés
- Instituto de Agrobiotecnología (IdAB), UPNA-CSIC-Gobierno de Navarra, Navarra 31192, Spain.
| | - Sergio Rosati
- Malattie Infettive degli Animali Domestici, Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, Torino 10095, Italy.
| | - Esperanza Gómez-Lucia
- Dpto. Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain.
| | - Ramsés Reina
- Instituto de Agrobiotecnología (IdAB), UPNA-CSIC-Gobierno de Navarra, Navarra 31192, Spain.
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6
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Wang HN, Rao D, Fu XQ, Hu MM, Dong JG. Equine infectious anemia virus in China. Oncotarget 2017; 9:1356-1364. [PMID: 29416700 PMCID: PMC5787444 DOI: 10.18632/oncotarget.20381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/09/2017] [Indexed: 11/25/2022] Open
Abstract
Equine infectious anemia is an equine disease caused by equine infectious anemia virus, which was first reported in 1840. Equine infectious anemia virus research in China started in the 1960s, focusing on etiology, pathology, diagnosis, and immunology. Notably, in 1978 an attenuated vaccine was successfully developed for equine infectious anemia virus, effectively preventing equine infectious anemia virus in China. This article will review equine infectious anemia virus in China, including past and recent research, and commemorate scientists who have made great contributions to equine infectious anemia virus prevention.
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Affiliation(s)
- Hua-Nan Wang
- Department of Veterinary Medicine, College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Dan Rao
- School of Animal Husbandry and Medical Engineering, Xinyang Agriculture and Forestry University, Xinyang, China.,Guangdong Key Laboratory of Laboratory Animals, Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China
| | - Xian-Qiu Fu
- The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ming-Ming Hu
- Shanxi Provincial Animal Disease Control Center, Taiyuan, China
| | - Jian-Guo Dong
- School of Animal Husbandry and Medical Engineering, Xinyang Agriculture and Forestry University, Xinyang, China
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7
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Wang XF, Lin YZ, Li Q, Liu Q, Zhao WW, Du C, Chen J, Wang X, Zhou JH. Genetic Evolution during the development of an attenuated EIAV vaccine. Retrovirology 2016; 13:9. [PMID: 26842878 PMCID: PMC4738788 DOI: 10.1186/s12977-016-0240-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 01/18/2016] [Indexed: 08/30/2023] Open
Abstract
Background The equine infectious anemia virus (EIAV) vaccine is the only attenuated lentiviral vaccine applied on a large scale that has been shown to be effective in controlling the prevalence of EIA in China. This vaccine was developed by successive passaging of a field-isolated virulent strain in different hosts and cultivated cells. To explore the molecular basis for the phenotype alteration of this vaccine strain, we systematically analyzed its genomic evolution during vaccine development. Results Sequence analysis revealed that the genetic distance between the wild-type strain and six representative strains isolated from key development stages gradually increased with the number of passages. Env gene, but not gag and pol, showed a clear evolutionary flow similar to that of the whole genomes of different generations during the attenuation. Stable mutations were identified in multiple regions of multiple genes along with virus passaging. The adaption of the virus to the growth environment of cultured cells with accumulated genomic and genetic variations was positively correlated with the reduction in pathogenicity and rise of immunogenicity. Statistical analyses revealed significant differences in the frequency of the most stable mutations between in vivo and ex vivo-adapted strains and between virulent and attenuated strains. Conclusions These data indicate that EIAV evolution during vaccine development generated an accumulation of mutations under the selective drive force, which helps to better understand the molecular basis of lentivirus pathogenicity and immunogenicity. Electronic supplementary material The online version of this article (doi:10.1186/s12977-016-0240-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. .,Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, China.
| | - Yue-Zhi Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Qiang Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. .,Harbin Weike Biotechnology Development Company, Harbin, China.
| | - Qiang Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Wei-Wei Zhao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Cheng Du
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Jie Chen
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Jian-Hua Zhou
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China. .,Harbin Pharmaceutical Group Biovaccine Co., Harbin, 150069, China.
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8
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Craigo JK, Ezzelarab C, Cook SJ, Liu C, Horohov D, Issel CJ, Montelaro RC. Protective efficacy of centralized and polyvalent envelope immunogens in an attenuated equine lentivirus vaccine. PLoS Pathog 2015; 11:e1004610. [PMID: 25569288 PMCID: PMC4287611 DOI: 10.1371/journal.ppat.1004610] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/07/2014] [Indexed: 11/18/2022] Open
Abstract
Lentiviral Envelope (Env) antigenic variation and related immune evasion present major hurdles to effective vaccine development. Centralized Env immunogens that minimize the genetic distance between vaccine proteins and circulating viral isolates are an area of increasing study in HIV vaccinology. To date, the efficacy of centralized immunogens has not been evaluated in the context of an animal model that could provide both immunogenicity and protective efficacy data. We previously reported on a live-attenuated (attenuated) equine infectious anemia (EIAV) virus vaccine, which provides 100% protection from disease after virulent, homologous, virus challenge. Further, protective efficacy demonstrated a significant, inverse, linear relationship between EIAV Env divergence and protection from disease when vaccinates were challenged with viral strains of increasing Env divergence from the vaccine strain Env. Here, we sought to comprehensively examine the protective efficacy of centralized immunogens in our attenuated vaccine platform. We developed, constructed, and extensively tested a consensus Env, which in a virulent proviral backbone generated a fully replication-competent pathogenic virus, and compared this consensus Env to an ancestral Env in our attenuated proviral backbone. A polyvalent attenuated vaccine was established for comparison to the centralized vaccines. Additionally, an engineered quasispecies challenge model was created for rigorous assessment of protective efficacy. Twenty-four EIAV-naïve animals were vaccinated and challenged along with six-control animals six months post-second inoculation. Pre-challenge data indicated the consensus Env was more broadly immunogenic than the Env of the other attenuated vaccines. However, challenge data demonstrated a significant increase in protective efficacy of the polyvalent vaccine. These findings reveal, for the first time, a consensus Env immunogen that generated a fully-functional, replication-competent lentivirus, which when experimentally evaluated, demonstrated broader immunogenicity that does not equate to higher protective efficacy.
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Affiliation(s)
- Jodi K. Craigo
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| | - Corin Ezzelarab
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Sheila J. Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Chong Liu
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - David Horohov
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Charles J. Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Ronald C. Montelaro
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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9
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Issel CJ, Cook RF, Mealey RH, Horohov DW. Equine infectious anemia in 2014: live with it or eradicate it? Vet Clin North Am Equine Pract 2014; 30:561-77. [PMID: 25441114 DOI: 10.1016/j.cveq.2014.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
In the absence of an effective vaccine, the success of the test and removal approach for the control of equine infectious anemia (EIA) cannot be overstated, at least in those areas where testing has been traditionally routine. This article addresses 4 main aspects: what has been learned about EIA virus, host control of its replication, and inapparent carriers; international status regarding the control of EIA; diagnostic and laboratory investigation; and reducing the spread of blood-borne infections by veterinarians. An attempt is made to put these issues into practical contemporary perspectives for the equine practitioner.
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Affiliation(s)
- Charles J Issel
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
| | - R Frank Cook
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
| | - Robert H Mealey
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, PO Box 647040, Pullman, WA 99164-7040, USA
| | - David W Horohov
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
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10
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Craigo JK, Montelaro RC. Lessons in AIDS vaccine development learned from studies of equine infectious, anemia virus infection and immunity. Viruses 2013; 5:2963-76. [PMID: 24316675 PMCID: PMC3967156 DOI: 10.3390/v5122963] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 11/20/2013] [Accepted: 11/25/2013] [Indexed: 11/16/2022] Open
Abstract
Equine infectious anemia (EIA), identified in 1843 [1] as an infectious disease of horses and as a viral infection in 1904, remains a concern in veterinary medicine today. Equine infectious anemia virus (EIAV) has served as an animal model of HIV-1/AIDS research since the original identification of HIV. Similar to other lentiviruses, EIAV has a high propensity for genomic sequence and antigenic variation, principally in its envelope (Env) proteins. However, EIAV possesses a unique and dynamic disease presentation that has facilitated comprehensive analyses of the interactions between the evolving virus population, progressive host immune responses, and the definition of viral and host correlates of immune control and vaccine efficacy. Summarized here are key findings in EIAV that have provided important lessons toward understanding long term immune control of lentivirus infections and the parameters for development of an enduring broadly protective AIDS vaccine.
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Affiliation(s)
- Jodi K Craigo
- Center for Vaccine Research, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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11
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Cook R, Leroux C, Issel C. Equine infectious anemia and equine infectious anemia virus in 2013: A review. Vet Microbiol 2013; 167:181-204. [DOI: 10.1016/j.vetmic.2013.09.031] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 09/16/2013] [Accepted: 09/21/2013] [Indexed: 10/26/2022]
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12
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Gao X, Jiang CG, Wang XF, Lin YZ, Ma J, Han XE, Zhao LP, Shen RX, Xiang WH, Zhou JH. Reverse mutation of the virulence-associated S2 gene does not cause an attenuated equine infectious anemia virus strain to revert to pathogenicity. Virology 2013; 443:321-8. [PMID: 23763769 DOI: 10.1016/j.virol.2013.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 04/24/2013] [Accepted: 05/10/2013] [Indexed: 11/15/2022]
Abstract
The contribution of S2 accessory gene of equine infectious anemia virus (EIAV) to the virulence of pathogenic strains was investigated in the present study by reverse mutation of all four consensus S2 mutation sites in an attenuated EIAV proviral strain, FDDV3-8, to the corresponding sequences of a highly pathogenic strain DV117. The S2 reverse-mutated recombinant strain FDDVS2r1-2-3-4 replicated with similar kinetics to FDDV3-8 in cultivated target cells. In contrast to the results of other studies of EIAV with dysfunctional S2, reverse mutation of S2 only transiently and moderately increased the plasma viral load of inoculated horses, and induction of transient immunosuppression did not boost viral pathogenicity. In addition, inoculation of FDDVS2r1-2-3-4 induced partial protection to a challenge pathogenic virus. These results suggest that the attenuated EIAV vaccine strain with multiple mutations in multiple genes will not easily revert to a virulent phenotype.
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Affiliation(s)
- Xu Gao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Harbin 150001, China
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13
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Craigo JK, Ezzelarab C, Cook SJ, Chong L, Horohov D, Issel CJ, Montelaro RC. Envelope determinants of equine lentiviral vaccine protection. PLoS One 2013; 8:e66093. [PMID: 23785473 PMCID: PMC3682429 DOI: 10.1371/journal.pone.0066093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/02/2013] [Indexed: 11/18/2022] Open
Abstract
Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection.
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Affiliation(s)
- Jodi K Craigo
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
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14
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Issel CJ, Scicluna MT, Cook SJ, Cook RF, Caprioli A, Ricci I, Rosone F, Craigo JK, Montelaro RC, Autorino GL. Challenges and proposed solutions for more accurate serological diagnosis of equine infectious anaemia. Vet Rec 2013; 172:210. [PMID: 23161812 PMCID: PMC3593188 DOI: 10.1136/vr-2012-100735] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2012] [Indexed: 11/21/2022]
Abstract
Serological diagnosis of equine infectious anaemia virus (EIAV) infections has depended mainly on the agar gel immunodiffusion test (AGIDT). This study documents the presence of EIAV genetic sequences in a number of persistently infected horses and mules whose serums were interpreted as negative/equivocal on AGIDT, but positive on more than one ELISA test and in immunoblot tests. Strategies designed to take advantage of the combined strengths of the ELISA and AGIDT are shown effective in a national surveillance program for EIA in Italy where 17 per cent (25/149) of the equids considered to be infected with EIAV on combined/comparative serological data had reactions in the AGIDT that were interpreted as negative or equivocal. These data document the benefits of using a three-tiered laboratory system for the diagnosis of EIA. Although the ELISA-first strategy introduces some confusing results, the discovery of up to 20 per cent more cases of EIA makes it compelling. In our opinion, it is better and more defensible to find two samples in 1000 with resolvable but falsely positive ELISA tests for EIA than to release two to three horses in 10,000 with falsely negative test results for EIA (the rates seen in the Italian surveillance presented here).
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Affiliation(s)
- C J Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington KY, USA.
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15
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Meng Q, Lin Y, Ma J, Ma Y, Zhao L, Li S, Yang K, Zhou J, Shen R, Zhang X, Shao Y. A pilot study comparing the development of EIAV Env-specific antibodies induced by DNA/recombinant vaccinia-vectored vaccines and an attenuated Chinese EIAV vaccine. Viral Immunol 2012; 25:477-84. [PMID: 23171359 DOI: 10.1089/vim.2012.0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Data from successful attenuated lentiviral vaccine studies indicate that fully mature Env-specific antibodies characterized by high titer, high avidity, and the predominant recognition of conformational epitopes are associated with protective efficacy. Although vaccination with a DNA prime/recombinant vaccinia-vectored vaccine boost strategy has been found to be effective in some trials with non-human primate/simian/human immunodeficiency virus (SHIV) models, it remains unclear whether this vaccination strategy could elicit mature equine infectious anemia virus (EIAV) Env-specific antibodies, thus protecting vaccinated horses against EIAV infection. Therefore, in this pilot study we vaccinated horses using a strategy based on DNA prime/recombinant Tiantan vaccinia (rTTV)-vectored vaccines encoding EIAV env and gag genes, and observed the development of Env-specific antibodies, neutralizing antibodies, and p26-specific antibodies. Vaccination with DNA induced low titer, low avidity, and the predominant recognition of linear epitopes by Env-specific antibodies, which was enhanced by boosting vaccinations with rTTV vaccines. However, the maturation levels of Env-specific antibodies induced by the DNA/rTTV vaccines were significantly lower than those induced by the attenuated vaccine EIAV(FDDV). Additionally, DNA/rTTV vaccines did not elicit broadly neutralizing antibodies. After challenge with a virulent EIAV strain, all of the vaccinees and control horses died from EIAV disease. These data indicate that the regimen of DNA prime/rTTV vaccine boost did not induce mature Env-specific antibodies, which might have contributed to immune protection failure.
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Affiliation(s)
- Qinglai Meng
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
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16
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Lin YZ, Shen RX, Zhu ZY, Deng XL, Cao XZ, Wang XF, Ma J, Jiang CG, Zhao LP, Lv XL, Shao YM, Zhou JH. An attenuated EIAV vaccine strain induces significantly different immune responses from its pathogenic parental strain although with similar in vivo replication pattern. Antiviral Res 2011; 92:292-304. [PMID: 21893100 DOI: 10.1016/j.antiviral.2011.08.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 07/25/2011] [Accepted: 08/18/2011] [Indexed: 01/06/2023]
Abstract
The EIAV (equine infectious anemia virus) multi-species attenuated vaccine EIAV(DLV121) successfully prevented the spread of equine infectious anemia (EIA) in China in the 1970s and provided an excellent model for the study of protective immunity to lentiviruses. In this study, we compared immune responses induced by EIAV(DLV121) to immunity elicited by the virulent EIAV(LN40) strain and correlated immune responses to protection from infection. Horses were randomly grouped and inoculated with either EIAV(DLV121) (Vaccinees, Vac) or a sublethal dose of EIAV(LN40) (asymptomatic carriers, Car). Car horses became EIAV(LN40) carriers without disease symptoms. Two of the four Vac horses were protected against infection and the other two had delayed onset or reduced severity of EIA with a lethal EIAV(LN40) challenge 5.5 months post initial inoculation. In contrast, all three Car animals developed acute EIA and two succumbed to death. Specific humoral and cellular immune responses in both Vac and Car groups were evaluated for potential correlations with protection. These analyses revealed that although plasma viral loads remained between 10(3) and 10(5)copies/ml for both groups before EIAV(LN40) challenge, Vac-treated animals developed significantly higher levels of conformational dependent, Env-specific antibody, neutralizing antibody as well as significantly elevated CD4(+) T cell proliferation and IFN-γ-secreting CD8(+) T cells than those observed in EIAV(LN40) asymptomatic carriers. Further analysis of protected and unprotected cases in vaccinated horses identified that cellular response parameters and the reciprocal anti-p26-specific antibody titers closely correlated with protection against infection with the pathogenic EIAV(LN40). These data provide a better understanding of protective immunity to lentiviruses.
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Affiliation(s)
- Yue-Zhi Lin
- State Key Laboratory of Veterinary Biotechnology, Division of Livestock Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China
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17
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Meng Q, Lin Y, Ma J, Ma Y, Zhao L, Li S, Liang H, Zhou J, Shen R, Zhang X, Shao Y. A pilot study on an attenuated Chinese EIAV vaccine inducing broadly neutralizing antibodies. Arch Virol 2011; 156:1455-62. [DOI: 10.1007/s00705-011-0992-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
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18
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Ma J, Shi N, Jiang CG, Lin YZ, Wang XF, Wang S, Lv XL, Zhao LP, Shao YM, Kong XG, Zhou JH, Shen RX. A proviral derivative from a reference attenuated EIAV vaccine strain failed to elicit protective immunity. Virology 2011; 410:96-106. [DOI: 10.1016/j.virol.2010.10.032] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 08/31/2010] [Accepted: 10/22/2010] [Indexed: 11/25/2022]
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19
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Reina R, Juganaru MM, Profiti M, Cascio P, Cerruti F, Bertolotti L, De Meneghi D, Amorena B, Rosati S. Immunological parameters in goats experimentally infected with SRLV genotype E, strain Roccaverano. Vet Immunol Immunopathol 2010; 139:237-44. [PMID: 21122927 DOI: 10.1016/j.vetimm.2010.11.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
Abstract
Genotype E of small ruminant lentivirus has been recently described in goats from different breeds in Italy. Genotype E infection may differ from known genotypes since deletions of dUTPase and VPR proteins have been confirmed in different independent areas and goat breed, and play a key role on virus replication and pathogenesis. In particular, genotype E Roccaverano strain has been described as low pathogenic since does not lead to clinical symptoms in goats. In contrast, classical CAEV infected goats of the same area and breed presented arthritis. In this study, we have used intratracheal and intra-bone marrow routes to establish genotype E persistent infections. Humoral and cellular immune responses elicited in the host against genotype E and genotype B derived antigens were evaluated until 200 days post-inoculation. Compared to genotype B antigen, seroconversion against genotype E GAG P16-25 antigen was detected at 2-3 weeks after inoculation, significantly earlier and at higher titres. Interestingly, antibody avidity did not increase in the course of the experiment neither against P16-25 nor against SU5, both derived from genotype E. T cell proliferation against P25-GST fusion protein antigens derived from genotype E was firstly detected at 15 days post-inoculation and was maintained throughout time until week 20 post-infection, while T cell proliferation against the genotype B P25 was not produced by the end of the experiment at 20 weeks post-inoculation. The strength of reaction was also higher when using P25 E as stimulator antigen. In contrast with antibody and T cell proliferation, cytotoxic-T-lymphocyte (CTL) activity in the circulating lymphocytes (effector cells) using blood-derived macrophages (BDM) as target cells, was not strain specific being surprisingly higher against genotype B infected antigen presenting cells (APCs). This is the first study reporting experimentally induced immunological changes in SRLV genotype E infection and indicates that CTL activity may be the adaptive immune response able to induce protection against heterologous infection.
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Affiliation(s)
- Ramses Reina
- Instituto de Agrobiotecnología, CSIC-Universidad Pública de Navarra-Gobierno de Navarra, Mutilva Baja, Navarra, Spain
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20
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Craigo JK, Barnes S, Cook SJ, Issel CJ, Montelaro RC. Divergence, not diversity of an attenuated equine lentivirus vaccine strain correlates with protection from disease. Vaccine 2010; 28:8095-104. [PMID: 20955830 DOI: 10.1016/j.vaccine.2010.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/17/2010] [Accepted: 10/01/2010] [Indexed: 10/18/2022]
Abstract
We recently reported an attenuated EIAV vaccine study that directly examined the effect of lentiviral envelope sequence variation on vaccine efficacy. The study [1] demonstrated for the first time the failure of an ancestral vaccine to protect and revealed a significant, inverse, linear relationship between envelope divergence and protection from disease. In the current study we examine in detail the evolution of the attenuated vaccine strain utilized in this previous study. We demonstrate here that the attenuated strain progressively evolved during the six-month pre-challenge period and that the observed protection from disease was significantly associated with divergence from the original vaccine strain.
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Affiliation(s)
- Jodi K Craigo
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261, USA
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21
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Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W. Amino acid mutations in the env gp90 protein that modify N-linked glycosylation of the Chinese EIAV vaccine strain enhance resistance to neutralizing antibodies. Viral Immunol 2010; 23:531-9. [PMID: 20883167 DOI: 10.1089/vim.2009.0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, designated g5, g9, and g10. To investigate the biological significance of these changes, reverse-mutated viruses were constructed in the backbone of the EIAV(FDDV) infectious molecular clone (pLGFD3). The resulting virus stocks were characterized for replication efficiency in donkey dermal cells and donkey MDM, and were tested for sensitivity to neutralization using sera from two ponies experimentally infected with EIAV(FDDV). The results clearly show that these mutations generated by site-directed mutagenesis resulted in cloned viruses with enhanced resistance to serum-neutralizing antibodies that were also able to recognize parental viruses. The results of this study indicate that these mutations play an important role in the attenuation of the EIAV vaccine strains.
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Affiliation(s)
- Xiue Han
- Heilongjiang Dairy Industry Technical Development Center, Northeast Agricultural University, Harbin, China.
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22
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Liu L, Wan Y, Wu L, Sun J, Li H, Li H, Ma L, Shao Y. Broader HIV-1 neutralizing antibody responses induced by envelope glycoprotein mutants based on the EIAV attenuated vaccine. Retrovirology 2010; 7:71. [PMID: 20807451 PMCID: PMC2940887 DOI: 10.1186/1742-4690-7-71] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 09/01/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In order to induce a potent and cross-reactive neutralizing antibody (nAb), an effective envelope immunogen is crucial for many viral vaccines, including the vaccine for the human immunodeficiency virus (HIV). The Chinese equine infectious anemia virus (EIAV) attenuated vaccine has controlled the epidemic of this virus after its vaccination in over 70 million equine animals during the last 3 decades in China. Data from our past studies demonstrate that the Env protein of this vaccine plays a pivotal role in protecting horses from both homologous and heterogeneous EIAV challenges. Therefore, the amino acid sequence information from the Chinese EIAV attenuated vaccine, in comparison with the parental wild-type EIAV strains, was applied to modify the corresponding region of the envelope glycoprotein of HIV-1 CN54. The direction of the mutations was made towards the amino acids conserved in the two EIAV vaccine strains, distinguishing them from the two wild-type strains. The purpose of the modification was to enhance the immunogenicity of the HIV Env. RESULTS The induced nAb by the modified HIV Env neutralized HIV-1 B and B'/C viruses at the highest titer of 1:270. Further studies showed that a single amino acid change in the C1 region accounts for the substantial enhancement in induction of anti-HIV-1 neutralizing antibodies. CONCLUSIONS This study shows that an HIV envelope modified by the information of another lentivirus vaccine induces effective broadly neutralizing antibodies. A single amino acid mutation was found to increase the immunogenicity of the HIV Env.
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Affiliation(s)
- Lianxing Liu
- State Key Laboratory for Infectious Diseases Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, 155 Changbai Road, Changping District, Beijing 102206, China
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23
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Qi X, Wang X, Wang S, Lin Y, Jiang C, Ma J, Zhao L, Lv X, Shen R, Wang F, Kong X, Su Z, Zhou J. Genomic analysis of an effective lentiviral vaccine-attenuated equine infectious anemia virus vaccine EIAV FDDV13. Virus Genes 2010; 41:86-98. [PMID: 20526660 DOI: 10.1007/s11262-010-0491-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 05/03/2010] [Indexed: 11/26/2022]
Abstract
Chinese equine infectious anemia virus (EIAV) attenuated vaccine is the first lentiviral vaccine with a successful application. In order to understand the correlation of viral genomic mutations with viral attenuation and with induced immunoprotective properties, we analyzed the proviral genome sequences of the EIAV-attenuated vaccine strain EIAV(FDDV13) (EIAV fetal donkey dermal cell-adapted vaccine) and its highly virulent parental strain EIAV(LN40). The sequences of these strains were compared with those of the major foreign EIAV strains. The results indicated a large genetic distance between the Chinese EIAV strain and the major EIAV strains in America and Japan. The Chinese strains belong to an independent phylogenetic branch. The divergence between the entire genome of the Chinese strains and that of other major EIAV strains is approximately 23%. The divergence rate in LTR is over 14%, whereas that in each open reading frame is over 20%. The gp90 exhibited a divergence of 35% in its nucleotide sequence and 40% in its amino acid sequence. The present study found that after long-term passage in vitro, EIAV(FDDV13) has accumulated many stable substitution mutations in each gene. These mutations at multiple sites in multiple genes of the vaccine strain, especially the conserved mutations, provide important references for further understanding the attenuation mechanism of Chinese EIAV-attenuated vaccine and the immunoprotection mechanism of lentiviral vaccines.
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Affiliation(s)
- Xu Qi
- Department of Neurology, First Affiliated Hospital of Harbin Medical University, Harbin, 150001, China
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24
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Covaleda L, Fuller FJ, Payne SL. EIAV S2 enhances pro-inflammatory cytokine and chemokine response in infected macrophages. Virology 2009; 397:217-23. [PMID: 19945727 DOI: 10.1016/j.virol.2009.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 10/06/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
Abstract
Equine infectious anemia virus (EIAV) infection is distinctive in that it causes a rapid onset of clinical disease relative to other retroviruses. In order to understand the interaction dynamics between EIAV and the host immune response, we explored the effects of EIAV and its S2 protein in the regulation of the cytokine and chemokine response in macrophages. EIAV infection markedly altered the expression pattern of a variety of pro-inflammatory cytokines and chemokines monitored in the study. Comparative studies in the cytokine response between EIAV(17) and EIAV(17DeltaS2) infection revealed that S2 enhances the expression of IL-1alpha, IL-1beta, IL-8, MCP-2, MIP-1beta and IP-10. Moreover, S2 specifically induced the expression of the newly discovered cytokine, IL-34. Taken together, these results may help explain the effect of cytokine and chemokine dysregulation in EIAV pathogenesis and suggest a role of S2 in optimizing the host cell environment to promote viral dissemination and replication.
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Affiliation(s)
- Lina Covaleda
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, MS4467, College Station, TX 77843-4467, USA
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Craigo JK, Barnes S, Zhang B, Cook SJ, Howe L, Issel CJ, Montelaro RC. An EIAV field isolate reveals much higher levels of subtype variability than currently reported for the equine lentivirus family. Retrovirology 2009; 6:95. [PMID: 19843328 PMCID: PMC2770520 DOI: 10.1186/1742-4690-6-95] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Accepted: 10/20/2009] [Indexed: 11/16/2022] Open
Abstract
Background Equine infectious anemia virus (EIAV), a lentivirus that infects horses, has been utilized as an animal model for the study of HIV. Furthermore, the disease associated with the equine lentivirus poses a significant challenge to veterinary medicine around the world. As with all lentiviruses, EIAV has been shown to have a high propensity for genomic sequence and antigenic variation, especially in its envelope (Env) proteins. Recent studies have demonstrated Env variation to be a major determinant of vaccine efficacy, emphasizing the importance of defining natural variation among field isolates of EIAV. To date, however, published EIAV sequences have been reported only for cell-adapted strains of virus, predominantly derived from a single primary virus isolate, EIAVWyoming (EIAVWY). Results We present here the first characterization of the Env protein of a natural primary isolate from Pennsylvania (EIAVPA) since the widely utilized and referenced EIAVWY strain. The data demonstrated that the level of EIAVPA Env amino acid sequence variation, approximately 40% as compared to EIAVWY, is much greater than current perceptions or published reports of natural EIAV variation between field isolates. This variation did not appear to give rise to changes in the predicted secondary structure of the proteins. While the EIAVPA Env was serologically cross reactive with the Env proteins of the cell-adapted reference strain, EIAVPV (derivative of EIAVWY), the two variant Envs were shown to lack any cross neutralization by immune serum from horses infected with the respective virus strains. Conclusion Taking into account the significance of serum neutralization to universal vaccine efficacy, these findings are crucial considerations towards successful EIAV vaccine development and the potential inclusion of field isolate Envs in vaccine candidates.
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Affiliation(s)
- Jodi K Craigo
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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26
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Ma J, Jiang C, Lin Y, Wang X, Zhao L, Xiang W, Shao Y, Shen R, Kong X, Zhou J. In vivo evolution of the gp90 gene and consistently low plasma viral load during transient immune suppression demonstrate the safety of an attenuated equine infectious anemia virus (EIAV) vaccine. Arch Virol 2009; 154:867-73. [PMID: 19363668 DOI: 10.1007/s00705-009-0378-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 03/30/2009] [Indexed: 10/20/2022]
Abstract
To study the in vivo evolution of the attenuated Chinese equine infectious anemia virus (EIAV) vaccine, viral gp90 gene variation and virus replication in immunosuppressed hosts were investigated. The results showed that after vaccination, the gp90 gene followed an evolutionary trend of declining diversity. The trend coincided with the maturation of immunity to EIAV, and eventually, the gp90 gene became highly homologous. The sequences of these predominant quasispecies were consistently detected up to 18 months after vaccination. Furthermore, after transient immune suppression with dexamethasone, the plasma viral RNA copy number of the vaccine strain in three vaccinated ponies remained consistently below the "pathogenic threshold" level, while the viral load increased by 25,000-fold in the positive control of an inapparent carrier of the parental virulent strain. This study is the first to provide evidence for the safety of an attenuated lentiviral vaccine with decreased genomic diversity and consistently low viral replication under suppressed immunity.
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Affiliation(s)
- Jian Ma
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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27
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Mealey RH, Leib SR, Littke MH, Wagner B, Horohov DW, McGuire TC. Viral load and clinical disease enhancement associated with a lentivirus cytotoxic T lymphocyte vaccine regimen. Vaccine 2009; 27:2453-68. [PMID: 19368787 DOI: 10.1016/j.vaccine.2009.02.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/04/2009] [Accepted: 02/18/2009] [Indexed: 10/21/2022]
Abstract
Effective DNA-based vaccines against lentiviruses will likely induce CTL against conserved viral proteins. Equine infectious anemia virus (EIAV) infects horses worldwide, and serves as a useful model for lentiviral immune control. Although attenuated live EIAV vaccines have induced protective immune responses, DNA-based vaccines have not. In particular, DNA-based vaccines have had limited success in inducing CTL responses against intracellular pathogens in the horse. We hypothesized that priming with a codon-optimized plasmid encoding EIAV Gag p15/p26 with co-administration of a plasmid encoding an equine IL-2/IgG fusion protein as a molecular adjuvant, followed by boosting with a vaccinia vector expressing Gag p15/p26, would induce protective Gag-specific CTL responses. Although the regimen induced Gag-specific CTL in four of seven vaccinated horses, CTL were not detected until after the vaccinia boost, and protective effects were not observed in EIAV challenged vaccinates. Unexpectedly, vaccinates had significantly higher viral loads and more severe clinical disease, associated with the presence of vaccine-induced CTL. It was concluded that (1) further optimization of the timing and route of DNA immunization was needed for efficient CTL priming in vivo, (2) co-administration of the IL-2/IgG plasmid did not enhance CTL priming by the Gag p15/p26 plasmid, (3) vaccinia vectors are useful for lentivirus-specific CTL induction in the horse, (4) Gag-specific CTL alone are either insufficient or a more robust Gag-specific CTL response is needed to limit EIAV viremia and clinical disease, and (5) CTL-inducing vaccines lacking envelope immunogens can result in lentiviral disease enhancement. Although the mechanisms for enhancement associated with this vaccine regimen remain to be elucidated, these results have important implications for development of lentivirus T cell vaccines.
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Affiliation(s)
- Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, 99164-7040, United States.
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28
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Envelope determinants of equine infectious anemia virus vaccine protection and the effects of sequence variation on immune recognition. J Virol 2008; 82:4052-63. [PMID: 18234792 DOI: 10.1128/jvi.02028-07] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A highly effective attenuated equine infectious anemia virus (EIAV) vaccine (EIAV(D9)) capable of protecting 100% of horses from disease induced by a homologous Env challenge strain (EIAV(PV)) was recently tested in ponies to determine the level of protection against divergent Env challenge strains (J. K. Craigo, B. S. Zhang, S. Barnes, T. L. Tagmyer, S. J. Cook, C. J. Issel, and R. C. Montelaro, Proc. Natl. Acad. Sci. USA 104:15105-15110, 2007). An inverse correlation between challenge strain Env variation and vaccine protection from disease was observed. Given the striking differences in protective immunity, we hypothesized that analysis of the humoral and cellular immune responses to the Env protein could reveal potential determinants of vaccine protection. Neutralization activity against the homologous Env or challenge strain-specific Env in immune sera from the vaccinated ponies did not correlate with protection from disease. Cellular analysis with Env peptide pools did not reveal an association with vaccine protection from disease. However, when individual vaccine-specific Env peptides were utilized, eight cytotoxic-T-lymphocyte (CTL) peptides were found to associate closely with vaccine protection. One of these peptides also yielded the only lymphoproliferative response associated with protective immunity. The identified peptides spanned both variable and conserved regions of gp90. Amino acid divergence within the principal neutralization domain and the identified peptides profoundly affected immune recognition, as illustrated by the inability to detect cross-reactive neutralizing antibodies and the observation that certain peptide-specific CTL responses were altered. In addition to identifying potential Env determinants of EIAV vaccine efficacy and demonstrating the profound effects of defined Env variation on immune recognition, these data also illustrate the sensitivity offered by individual peptides compared to peptide pools in measuring cellular immune responses in lentiviral vaccine trials.
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Nagarajan MM, Simard C. Gag genetic heterogeneity of equine infectious anemia virus (EIAV) in naturally infected horses in Canada. Virus Res 2007; 129:228-35. [PMID: 17767972 DOI: 10.1016/j.virusres.2007.07.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 07/07/2007] [Accepted: 07/09/2007] [Indexed: 11/19/2022]
Abstract
Gag genetic heterogeneity of equine infectious anemia virus (EIAV) variants in naturally infected horses in Canada was studied since very limited information is available on the variability of EIAV Gag sequences in public database. A phylogenetic analysis based on 414nts of Gag gene sequences amplified by a nested polymerase chain reaction (PCR) revealed the distinct divergence of these variants compared to other published strains in a corresponding region. Significant predicted amino acid sequence variations were also identified in an immunorelevant region within this fragment which corresponded to a previously characterized cytotoxic T lymphocytes (CTL) epitope cluster (EC2, aa 77-119). Furthermore, alignment of the predicted full-length Gag protein gene sequences of some of these variants associated with clinical cases of EIA in Canada with the published sequences of EIAV originating from other countries revealed conserved and variant sequences in regions corresponding to other characterized CTL epitope clusters, EC1, EC3 and EC4. Conserved sequences identified among different variant strains might have an important implication for their screening and selection of putative peptide epitopes to mediate relevant immune response and cross protection against divergent field strains of EIAV.
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Affiliation(s)
- Malliga M Nagarajan
- St-Hyacinthe Laboratory, Canadian Food Inspection Agency, St-Hyacinthe, QC, J2S 8E3, Canada.
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Craigo JK, Zhang B, Barnes S, Tagmyer TL, Cook SJ, Issel CJ, Montelaro RC. Envelope variation as a primary determinant of lentiviral vaccine efficacy. Proc Natl Acad Sci U S A 2007; 104:15105-10. [PMID: 17846425 PMCID: PMC1986620 DOI: 10.1073/pnas.0706449104] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lentiviral envelope antigenic variation and associated immune evasion are believed to present major obstacles to effective vaccine development. Although this perception is widely assumed by the scientific community, there is, to date, no rigorous experimental data assessing the effect of increasing levels of lentiviral Env variation on vaccine efficacy. It is our working hypothesis that Env is, in fact, a primary determinant of vaccine effectiveness. We previously reported that a successful experimental attenuated equine infectious anemia virus vaccine, derived by mutation of the viral S2 accessory gene, provided 100% protection from disease after virulent virus challenge. Here, we sought to comprehensively test our hypothesis by challenging vaccinated animals with proviral strains of defined, increasing Env variation, using variant envelope SU genes that arose naturally during experimental infection of ponies with equine infectious anemia virus. The reference attenuated vaccine combined with these variant Env challenge strains facilitated evaluation of the protection conferred by ancestral immunogens, because the Env of the attenuated vaccine is a direct ancestor to the variant proviral strain Envs. The results demonstrated that ancestral Env proteins did not impart broad levels of protection against challenge. Furthermore, the results displayed a significant inverse linear correlation of Env divergence and protection from disease. This study demonstrates potential obstacles to the use of single isolate ancestral Env immunogens. Finally, these findings reveal that relatively minor Env variation can pose a substantial challenge to lentiviral vaccine immunity, even when attenuated vaccines are used that, to date, achieve the highest levels of vaccine protection.
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Affiliation(s)
- Jodi K. Craigo
- *Center for Vaccine Research
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Baoshan Zhang
- *Center for Vaccine Research
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Shannon Barnes
- *Center for Vaccine Research
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Tara L. Tagmyer
- *Center for Vaccine Research
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA 15261; and
| | - Sheila J. Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Charles J. Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Ronald C. Montelaro
- *Center for Vaccine Research
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh, Pittsburgh, PA 15261; and
- To whom correspondence should be addressed at:
Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261. E-mail:
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FIV as a Model for HIV: An Overview. IN VIVO MODELS OF HIV DISEASE AND CONTROL 2007. [PMCID: PMC7121254 DOI: 10.1007/0-387-25741-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Animal models for human immunodeficiency virus (HIV) infection play a key role in understanding the pathogenesis of AIDS and the development of therapeutic agents and vaccines. As the only lentivirus that causes an immunodeficiency resembling that of HIV infection, in its natural host, feline immunodeficiency virus (FIV) has been a unique and powerful model for AIDS research. FIV was first described in 1987 by Niels Pedersen and co-workers as the causative agent for a fatal immunodeficiency syndrome observed in cats housed in a cattery in Petaluma, California. Since this landmark observation, multiple studies have shown that natural and experimental infection of cats with biological isolates of FIV produces an AIDS syndrome very similar in pathogenesis to that observed for human AIDS. FIV infection induces an acute viremia associated with Tcell alterations including depressed CD4 :CD8 T-cell ratios and CD4 T-cell depletion, peripheral lymphadenopathy, and neutropenia. In later stages of FIV infection, the host suffers from chronic persistent infections that are typically self-limiting in an immunocompetent host, as well as opportunistic infections, chronic diarrhea and wasting, blood dyscracias, significant CD4 T-cell depletion, neurologic disorders, and B-cell lymphomas. Importantly, chronic FIV infection induces a progressive lymphoid and CD4 T-cell depletion in the infected cat. The primary mode of natural FIV transmission appears to be blood-borne facilitated by fighting and biting. However, experimental infection through transmucosal routes (rectal and vaginal mucosa and perinatal) have been well documented for specific FIV isolates. Accordingly, FIV disease pathogenesis exhibits striking similarities to that described for HIV-1 infection.
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Zhang X, Wang Y, Liang H, Wei L, Xiang W, Shen R, Shao Y. Correlation between the induction of Th1 cytokines by an attenuated equine infectious anemia virus vaccine and protection against disease progression. J Gen Virol 2007; 88:998-1004. [PMID: 17325374 DOI: 10.1099/vir.0.82416-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) has been used to protect against equine infectious anaemia (EIA) disease for several decades in China. The attenuated mechanism and immunological protective mechanisms remain to be elucidated. To identify responses that correlate with the protection against disease, we immunized horses with DLV, followed by challenge with an EIAV wild-type strain LN. All vaccinated horses were asymptomatic and had a low level of virus replication (<10 copies ml-1). The expression level of cytokines including gamma interferon, interleukin 2 and 12 in DLV immunized horses was 5-100-fold higher than that in non-vaccinated controls (n=4, P<0.01). After challenge with virulent LN, horses vaccinated with DLV showed lower viral loads (<10(3) copies ml-1) with no temperature increase, except for one transient febrile episode in one animal. In contrast, horses in the non-vaccinated control group experienced much higher viral loads (>10(7) copies ml-1) and intermittent febrile episodes. Cytokine production in the DLV-vaccinated horses increased and attained a plateau level at approximately 50 days post-vaccination, and exceeded 10(7) copies per 10(7) peripheral blood mononuclear cells (PBMCs) 1-3 months post-challenge. However, non-vaccinated control horses died after several fever episodes (>or=39 degrees C), which coincided with higher viral load (10(6)-10(7) copies ml-1) and lower cytokine production (<10(4) copies per 10(7) PBMCs). The results indicate that high levels of EIAV-specific cytokines induced by the attenuated EIAV vaccine may contribute to the protective immune response against EIA disease.
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Affiliation(s)
- Xiaoyan Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China
| | - Ying Wang
- Harbin Veterinary Research Institute, Harbin 150086, China
| | - Hua Liang
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China
| | - Li Wei
- Harbin Veterinary Research Institute, Harbin 150086, China
| | - Wenhua Xiang
- Harbin Veterinary Research Institute, Harbin 150086, China
| | - Rongxian Shen
- Harbin Veterinary Research Institute, Harbin 150086, China
| | - Yiming Shao
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, China CDC, Beijing 100050, China
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Tagmyer TL, Craigo JK, Cook SJ, Issel CJ, Montelaro RC. Envelope-specific T-helper and cytotoxic T-lymphocyte responses associated with protective immunity to equine infectious anemia virus. J Gen Virol 2007; 88:1324-1336. [PMID: 17374779 DOI: 10.1099/vir.0.82391-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Equine infectious anemia virus (EIAV) infection of horses provides a valuable model for examining the natural immunological control of lentivirus infection and disease and the mechanisms of protective and enhancing vaccine immunity. We have previously hypothesized that the EIAV envelope (Env) proteins gp90 and gp45 are major determinants of vaccine efficacy, and that the development of protective immunity by attenuated viral vaccines may be associated with the progressive redirection of immune responses from immunodominant, variable Env segments to immunorecessive, conserved Env sequences. Whilst the antibody-neutralization determinants of Env have been defined, there are to date no comprehensive analyses of the lymphoproliferative (T-helper, Th) and cytotoxic T-cell (CTL) epitopes of the EIAV Env proteins. Thus, in the current study, synthetic-peptide methodologies were used to define regions of EIAV Env associated with protective vaccine immunity in a panel of 12 horses inoculated with the attenuated EIAVD9 vaccine and two asymptomatic carrier horses infected experimentally with the virulent EIAVPV strain expressing the same Env protein as the vaccine strain. The results of these studies identified 17 broadly reactive Th peptides and six broadly reactive CTL peptides in the Env proteins of EIAV that were associated with protective immunity. Thus, these data provide for the first time a comprehensive mapping of EIAV Env-specific cellular regions that can be used to examine the development of protective immunity and to evaluate potential cellular immune determinants of protective immunity.
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Affiliation(s)
- Tara L Tagmyer
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Molecular Virology and Microbiology Graduate Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Jodi K Craigo
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Sheila J Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516, USA
| | - Charles J Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516, USA
| | - Ronald C Montelaro
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Craigo JK, Durkin S, Sturgeon TJ, Tagmyer T, Cook SJ, Issel CJ, Montelaro RC. Immune suppression of challenged vaccinates as a rigorous assessment of sterile protection by lentiviral vaccines. Vaccine 2006; 25:834-45. [PMID: 17023099 PMCID: PMC1855206 DOI: 10.1016/j.vaccine.2006.09.040] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 08/21/2006] [Accepted: 09/07/2006] [Indexed: 01/19/2023]
Abstract
We previously reported that an experimental live-attenuated equine infectious anemia virus (EIAV) vaccine, containing a mutated S2 accessory gene, provided protection from disease and detectable infection after virulent virus (EIAV(PV)) challenge [Li F, Craigo JK, Howe L, Steckbeck JD, Cook S, Issel C, et al. A live-attenuated equine infectious anemia virus proviral vaccine with a modified S2 gene provides protection from detectable infection by intravenous virulent virus challenge of experimentally inoculated horses. J Virol 2003;77(13):7244-53; Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, et al. Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. J Virol 2005;79(5):2666-77]. To determine if attenuated EIAV vaccines actually prevent persistent infection by challenge virus, we employed a 14-day dexamethasone treatment of vaccinated horses post-challenge to suppress host immunity and amplify replication levels of any infecting EIAV. At 2 months post-challenge the horses were all protected from virulent-virus challenge, evidenced by a lack of EIA signs and detectable challenge plasma viral RNA. Upon immune suppression, 6/12 horses displayed clinical EIA. Post-immune suppression characterizations demonstrated that the attenuated vaccine evidently prevented detectable challenge virus infection in 50% of horses. These data highlight the utility of post-challenge immune suppression for evaluating persistent viral vaccine protective efficacy.
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Affiliation(s)
- Jodi K. Craigo
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Shannon Durkin
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Timothy J. Sturgeon
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Tara Tagmyer
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
| | - Sheila J. Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Charles J. Issel
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40516
| | - Ronald C. Montelaro
- Department of Molecular Genetics and Biochemistry, University of Kentucky, Lexington, KY 40516
- *Corresponding Author: Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, Phone: 412-648-8869, Fax: 412-383-8859,
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Steckbeck JD, Grieser HJ, Sturgeon T, Taber R, Chow A, Bruno J, Murphy-Corb M, Montelaro RC, Cole KS. Dynamic evolution of antibody populations in a rhesus macaque infected with attenuated simian immunodeficiency virus identified by surface plasmon resonance. J Med Primatol 2006; 35:248-60. [PMID: 16872288 PMCID: PMC3361734 DOI: 10.1111/j.1600-0684.2006.00173.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Increasing evidence suggests that an effective AIDS vaccine will need to elicit broadly neutralizing antibody responses. However, the mechanisms of antibody-mediated neutralization have not been defined. Previous studies from our lab have identified significant differences in the rates of antibody binding to trimeric SIV envelope proteins that correlate with neutralization sensitivity. Importantly, these results demonstrate differences in monoclonal antibody (MAb) binding to neutralization-sensitive and neutralization-resistant envelope proteins, suggesting that one mechanism for virus neutralization may be related to the stability of antibody binding. To date, little has been done to evaluate the binding properties of polyclonal serum antibodies elicited by SIV infection or vaccination. METHODS In the current study, we translate these findings with MAbs to study antibody binding properties of polyclonal serum antibody responses generated in rhesus macaques infected with attenuated SIV. Quantitative and qualitative binding properties of well-characterized longitudinal serum samples to trimeric, recombinant SIV gp140 envelope proteins were analyzed using surface plasmon resonance (SPR) technology (Biacore). RESULTS Results from these studies identified two antibody populations in most of the samples analyzed; one antibody population exhibited fast association/dissociation rates (unstable) while the other population demonstrated slower association/dissociation rates (stable). Over time, the percentage of the total binding response of each antibody population evolved, demonstrating a dynamic evolution of the antibody response that was consistent with the maturation of antibody responses defined using our standard panel of serological assays. However, the current studies provided a higher resolution analysis of polyclonal antibody binding properties, particularly with respect to the early time-points post-infection (PI), that is not possible with standard serological assays. More importantly, the increased stability of the antibody population with time PI corresponded with potent neutralization of homologous SIV in vitro. CONCLUSIONS These results suggest that the stability of the antibody-envelope interaction may be an important mechanism of serum antibody virus neutralization. In addition, measurements of the 'apparent' rates of association and dissociation may offer unique numerical descriptors to characterize the level of antibody maturation achieved by candidate vaccine strategies capable of eliciting broadly neutralizing antibody responses.
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Affiliation(s)
- J D Steckbeck
- Department of Medicine, Infectious Diseases Division, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Fagerness AJ, Flaherty MT, Perry ST, Jia B, Payne SL, Fuller FJ. The S2 accessory gene of equine infectious anemia virus is essential for expression of disease in ponies. Virology 2006; 349:22-30. [PMID: 16503341 DOI: 10.1016/j.virol.2005.12.041] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Revised: 11/12/2005] [Accepted: 12/22/2005] [Indexed: 10/25/2022]
Abstract
Equine infectious anemia virus (EIAV) is a macrophage-tropic lentivirus that persistently infects horses and causes a disease that is characterized by periodic episodes of fever, thrombocytopenia, and viremia. EIAV encodes only four regulatory/accessory genes, (tat, rev, ttm, and S2) and is the least genetically complex of all known lentiviruses. We sought to determine the role of the EIAV S2 accessory gene of EIAV by introducing mutations that would prevent S2 expression on the p19/wenv17 infectious molecular clone. Virus derived from the p19/wenv17 molecular clone is highly virulent and routinely fatal when given in high doses (J. Virol. 72 (1998) 483). In contrast, an S2 deletion mutant on the p19/wenv17 background is unable to induce acute disease and plasma virus loads were reduced by 2.5 to 4.0 logs at 15 days post-infection. The S2 deleted virus failed to produce any detectable clinical signs during a 5-month observation period. These results demonstrate that S2 gene expression is essential for disease expression of EIAV.
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Affiliation(s)
- Angela J Fagerness
- Department of Public Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606-8401, USA.
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Liang H, He X, Shen RX, Shen T, Tong X, Ma Y, Xiang WH, Zhang XY, Shao YM. Combined amino acid mutations occurring in the envelope closely correlate with pathogenicity of EIAV. Arch Virol 2006; 151:1387-403. [PMID: 16502285 DOI: 10.1007/s00705-005-0718-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Accepted: 11/29/2005] [Indexed: 11/26/2022]
Abstract
The Chinese equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) provides a unique natural model system to study the attenuation mechanism and immunological control of lentivirus replication. Critical consensus mutations were identified between virulent Chinese EIAV strains and vaccine strains. Based on a full-length infectious clone of EIAV vaccine strain pLGFD3, two molecular clones, mFD5-4-7 and mFD7-2-11, were successfully constructed, in which 4 and 6 critical consensus mutations in the env gene of the vaccine strain were point-mutated to the wild-type sequence, respectively by an overlap PCR mutagenesis strategy. The infectivity, virulence, and pathogenesis of the constructed clones were investigated in vitro using a reverse transcriptase assay, an indirect immunofluorescence assay, observation of cytopathogenic effect, and virion observation as well as in vivo by inoculation of animals with the resulting infectious clones. The pathogenic symptoms in horses inoculated with mFD7-2-11 were more severe than those inoculated with mFD5-4-7, whereas no pathogenic symptoms were detected in animals inoculated with their parental clone pLGFD3 strain. The results indicate that the consensus mutation residues of the env region involved in this study play significant roles in the virulence and pathogenicity of EIAV. This will contribute to the elucidation of the attenuating and protective mechanisms of the Chinese EIAV vaccine.
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MESH Headings
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Body Temperature
- Cell Line
- Cytopathogenic Effect, Viral
- Disease Models, Animal
- Equidae
- Equine Infectious Anemia/physiopathology
- Equine Infectious Anemia/virology
- Fluorescent Antibody Technique, Direct
- Gene Products, env/chemistry
- Gene Products, env/genetics
- Genes, env
- Horses
- Infectious Anemia Virus, Equine/genetics
- Infectious Anemia Virus, Equine/pathogenicity
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Platelet Count
- Point Mutation
- Sequence Alignment
- Vaccines, Attenuated/genetics
- Viral Vaccines/genetics
- Virulence/genetics
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Affiliation(s)
- H Liang
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, PR China
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Cook RF, Cook SJ, Bolin PS, Howe LJ, Zhou W, Montelaro RC, Issel CJ. Genetic immunization with codon-optimized equine infectious anemia virus (EIAV) surface unit (SU) envelope protein gene sequences stimulates immune responses in ponies. Vet Microbiol 2005; 108:23-37. [PMID: 15885929 DOI: 10.1016/j.vetmic.2005.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Revised: 04/05/2005] [Accepted: 04/07/2005] [Indexed: 10/25/2022]
Abstract
In the context of DNA vaccines the native equine infectious anemia virus (EIAV)-envelope gene has proven to be an extremely weak immunogen in horses probably because the RNA transcripts are poorly expressed owing to an unusual codon-usage bias, the possession of multiple RNA splice sites and potential adenosine-rich RNA instability elements. To overcome these problems a synthetic version of sequences encoding the EIAV surface unit (SU) envelope glycoprotein was produced (SYNSU) in which the codon-usage bias was modified to conform to that of highly expressed horse and human genes. In transfected COS-1 cell cultures, the steady state expression levels of SYNSU were at least 30-fold greater than equivalent native SU sequences. More importantly, EIAV-specific humoral and lymphocyte proliferation responses were induced in ponies immunized with a mammalian expression vector encoding SYNSU. However, these immunological responses were unable to confer protection against infection with a virulent EIAV strain.
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Affiliation(s)
- R Frank Cook
- Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
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Jin S, Issel CJ, Montelaro RC. Serological method using recombinant S2 protein to differentiate equine infectious anemia virus (EIAV)-infected and EIAV-vaccinated horses. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 11:1120-9. [PMID: 15539516 PMCID: PMC524783 DOI: 10.1128/cdli.11.6.1120-1129.2004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We recently reported a highly protective attenuated live virus vaccine for equine infectious anemia virus (EIAV) based on a proviral construct (EIAVUKDeltaS2) with a genetically engineered mutation in the viral S2 gene that eliminates expression of this accessory protein. While the EIAVUKDeltaS2 vaccine provides protection from detectable infection by experimental challenge with highly virulent virus, the potential for commercial application of this vaccine is complicated by the fact that horses inoculated with the EIAVUKDeltaS2 vaccine strain become seropositive in various reference diagnostic assays based on detection of antibodies to virion core or envelope proteins. To address this issue, we describe here the development and optimization of a new serologic EIAV diagnostic enzyme-linked immunosorbent assay (ELISA) to detect serum antibodies to the EIAV S2 protein that are produced in infected horses but not in horses inoculated with the EIAVUKDeltaS2 vaccine virus. The test S2 protein antigen was developed using the S2 gene sequence from the EIAVUK strain of virus and a series of modifications to facilitate production and purification of the diagnostic antigen, designated HS2G. Using this HS2G as antigen, we describe the development of an affinity ELISA that provides a sensitive and specific detection of S2-specific serum antibodies in experimentally and field-infected horses (22 of 24), without detectable reactivity with immune serum from uninfected (12 of 12) or vaccinated (29 of 29) horses. These data indicate that the S2-based diagnostic ELISA has the potential to accurately differentiate horses infected with EIAV from horses inoculated with an attenuated EIAV vaccine strain with a mutant S2 gene.
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Affiliation(s)
- Sha Jin
- Department of Molecular Genetics and Biochemistry, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
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40
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Pétursson G, Matthíasdóttir S, Svansson V, Andrésdóttir V, Georgsson G, Martin AH, Agnarsdóttir G, Gísladóttir E, Arnadóttir S, Högnadóttir S, Jónsson SR, Andrésson OS, Torsteinsdóttir S. Mucosal vaccination with an attenuated maedi–visna virus clone. Vaccine 2005; 23:3223-8. [PMID: 15837223 DOI: 10.1016/j.vaccine.2004.11.074] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 11/24/2004] [Indexed: 10/25/2022]
Abstract
Four sheep were infected intratracheally with an attenuated molecular clone of maedi-visna virus (MVV). All four became infected. Ten months later these sheep were challenged intratracheally with a genetically similar but pathogenic clone of MVV. Four unvaccinated sheep were infected simultaneously. All sheep became infected by the challenge virus. The vaccinated sheep were not protected against superinfection with the challenge clone. However, virus was isolated more frequently from the blood of the unvaccinated controls than of the vaccinated animals and ten times more frequently from lungs of unvaccinated sheep than from lungs of vaccinated sheep at sacrifice, indicating partial protection.
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Affiliation(s)
- Gudmundur Pétursson
- Institute for Experimental Pathology, University of Iceland, Keldur v/Vesturlandsveg, Reykjavik, Iceland.
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Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, Issel C, Montelaro RC. Discerning an effective balance between equine infectious anemia virus attenuation and vaccine efficacy. J Virol 2005; 79:2666-77. [PMID: 15708986 PMCID: PMC548432 DOI: 10.1128/jvi.79.5.2666-2677.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine efficacy, we examine here the relationship between the extent of virus attenuation, the maturation of host immune responses, and vaccine efficacy in a comparative study of three related attenuated EIAV proviral vaccine strains: the previously described EIAV(UK)DeltaS2 derived from a virulent proviral clone, EIAV(UK)DeltaS2/DU containing a second gene mutation in the virulent proviral clone, and EIAV(PR)DeltaS2 derived from a reference avirulent proviral clone. Inoculations of parallel groups of eight horses resulted in relatively low levels of viral replication (average of 10(2) to 10(3) RNA copies/ml) and a similar maturation of EIAV envelope-specific antibody responses as determined in quantitative and qualitative serological assays. However, experimental challenge of the experimentally immunized horses by our standard virulent EIAV(PV) strain by using a low-dose multiple exposure protocol (three inoculations with 10 median horse infective doses, administered intravenously) revealed a marked difference in the protective efficacy of the various attenuated proviral vaccine strains that was evidently associated with the extent of vaccine virus attenuation, time of viral challenge, and the apparent maturation of virus-specific immunity.
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Affiliation(s)
- Jodi K Craigo
- Department of Molecular Genetics and Biochemistry, W1144 Biomedical Science Tower, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Howe L, Craigo JK, Issel CJ, Montelaro RC. Specificity of serum neutralizing antibodies induced by transient immune suppression of inapparent carrier ponies infected with a neutralization-resistant equine infectious anemia virus envelope strain. J Gen Virol 2005; 86:139-149. [PMID: 15604441 DOI: 10.1099/vir.0.80374-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
It has been previously reported that transient corticosteroid immune suppression of ponies experimentally infected with a highly neutralization resistant envelope variant of equine infectious anemia virus (EIAV), designated EIAVΔPND, resulted in the appearance of type-specific serum antibodies to the infecting EIAVΔPNDvirus. The current study was designed to determine if this induction of serum neutralizing antibodies was associated with changes in the specificity of envelope determinants targeted by serum antibodies or caused by changes in the nature of the antibodies targeted to previously defined surface envelope gp90 V3 and V4 neutralization determinants. To address this question, the envelope determinants of neutralization by post-immune suppression serum were mapped. The results demonstrated that the neutralization sensitivity to post-immune suppression serum antibodies mapped specifically to the surface envelope gp90 V3 and V4 domains, individually or in combination. Thus, these data indicate that the development of serum neutralizing antibodies to the resistant EIAVΔPNDwas due to an enhancement of host antibody responses caused by transient immune suppression and the associated increase in virus replication.
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Affiliation(s)
- Laryssa Howe
- Department of Infectious Disease and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jodi K Craigo
- Department of Molecular Genetics and Biochemistry, School of Medicine, University of Pittsburgh, W1144 Biomedical Science Tower, Pittsburgh, PA 15261, USA
| | - Charles J Issel
- Department of Veterinary Sciences, Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA
| | - Ronald C Montelaro
- Department of Molecular Genetics and Biochemistry, School of Medicine, University of Pittsburgh, W1144 Biomedical Science Tower, Pittsburgh, PA 15261, USA
- Department of Infectious Disease and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
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