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Zhang Z, Guo K, Chu X, Liu M, Du C, Hu Z, Wang X. Development and evaluation of a test strip for the rapid detection of antibody against equine infectious anemia virus. Appl Microbiol Biotechnol 2024; 108:85. [PMID: 38189948 PMCID: PMC10774152 DOI: 10.1007/s00253-023-12980-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/06/2023] [Accepted: 12/20/2023] [Indexed: 01/09/2024]
Abstract
Equine infectious anemia (EIA) is a contagious disease of horses caused by the equine infectious anemia virus (EIAV). The clinical signs at the acute phase include intermittent high fever, thrombocytopenia, hemorrhage, edema, and anemia. The clinical signs at chronic and relapsing subclinical levels include emaciation and progressive weakness. Surviving horses become lifelong carriers because of the integration of the viral genome into that of the host, and these horses can produce and transmit the virus to other animals. This increases the difficulty of imposing practical control measures to prevent epidemics of this disease. Serological tests measuring the antibodies in equine sera are considered to be a reliable tool for the long-term monitoring of EIA. However, the standard serological tests for EIV either have low sensitivity (e.g., agar gel immunodiffusion test, AGID) or are time consuming to perform (e.g., ELISA and western blotting). The development of a rapid and simple method for detecting the disease is therefore critical to control the spread of EIA. In this study, we designed and developed a colloidal gold immunochromatographic (GICG) test strip to detect antibodies against EIAV based on the double-antigen sandwich. Both the p26 and gp45 proteins were used as the capture antigens, which may help to improve the positive detection rate of the strip. We found that the sensitivity of the test strip was 8 to 16 times higher than those of two commercially available ELISA tests and 128 to 256 times higher than AGID, but 8 to 16 times lower than that of western blotting. The strip has good specificity and stability. When serum samples from experimental horses immunized with the attenuated EIAV vaccine (n = 31) were tested, the results of the test strip showed 100% coincidence with those from NECVB-cELISA and 70.97% with AGID. When testing clinical serum samples (n = 1014), the test strip surprisingly provided greater sensitivity and a higher number of "true positive" results than other techniques. Therefore, we believe that the GICG test strip has demonstrated great potential in the field trials as a simple and effective tool for the detection of antibodies against EIAV. KEY POINTS: • A colloidal gold immunochromatographic (GICG) fast test strip was developed with good specificity, sensitivity, stability, and repeatability • The test strip can be used in point-of-care testing for the primary screening of EIAV antibodies • Both the p26 and gp45 proteins were used as the capture antigens, giving a high positive detection rate in the testing of experimentally infected animal and field samples.
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Affiliation(s)
- Zenan Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Kui Guo
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaoyu Chu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
- Institute of Western Agriculture, the Chinese Academy of Agricultural Sciences, Changji, China
- WOAH Reference Laboratory for Equine Infectious Anemia, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China
| | - Mingru Liu
- Shenzhen Lvshiyuan Biotechnology Co., Shenzhen, China
| | - Cheng Du
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
- WOAH Reference Laboratory for Equine Infectious Anemia, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
| | - Zhe Hu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
- WOAH Reference Laboratory for Equine Infectious Anemia, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
| | - Xiaojun Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
- Institute of Western Agriculture, the Chinese Academy of Agricultural Sciences, Changji, China.
- WOAH Reference Laboratory for Equine Infectious Anemia, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, China.
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Application across species of a one health approach to liquid sample handling for respiratory based -omics analysis. Sci Rep 2021; 11:14292. [PMID: 34253818 PMCID: PMC8275668 DOI: 10.1038/s41598-021-93839-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 06/25/2021] [Indexed: 01/19/2023] Open
Abstract
Airway inflammation is highly prevalent in horses, with the majority of non-infectious cases being defined as equine asthma. Currently, cytological analysis of airway derived samples is the principal method of assessing lower airway inflammation. Samples can be obtained by tracheal wash (TW) or by lavage of the lower respiratory tract (bronchoalveolar lavage (BAL) fluid; BALF). Although BALF cytology carries significant diagnostic advantages over TW cytology for the diagnosis of equine asthma, sample acquisition is invasive, making it prohibitive for routine and sequential screening of airway health. However, recent technological advances in sample collection and processing have made it possible to determine whether a wider range of analyses might be applied to TW samples. Considering that TW samples are relatively simple to collect, minimally invasive and readily available in the horse, it was considered appropriate to investigate whether, equine tracheal secretions represent a rich source of cells and both transcriptomic and proteomic data. Similar approaches have already been applied to a comparable sample set in humans; namely, induced sputum. Sputum represents a readily available source of airway biofluids enriched in proteins, changes in the expression of which may reveal novel mechanisms in the pathogenesis of respiratory diseases, such as asthma and chronic obstructive pulmonary disease. The aim of this study was to establish a robust protocol to isolate macrophages, protein and RNA for molecular characterization of TW samples and demonstrate the applicability of sample handling to rodent and human pediatric bronchoalveolar lavage fluid isolates. TW samples provided a good quality and yield of both RNA and protein for downstream transcriptomic/proteomic analyses. The sample handling methodologies were successfully applicable to BALF for rodent and human research. TW samples represent a rich source of airway cells, and molecular analysis to facilitate and study airway inflammation, based on both transcriptomic and proteomic analysis. This study provides a necessary methodological platform for future transcriptomic and/or proteomic studies on equine lower respiratory tract secretions and BALF samples from humans and mice.
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Molecular detection, histopathological analysis, and immunohistochemical characterization of equine infectious anemia virus in naturally infected equids. Arch Virol 2020; 165:1333-1342. [PMID: 32266552 DOI: 10.1007/s00705-020-04616-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 03/17/2020] [Indexed: 10/24/2022]
Abstract
Equine infectious anemia (EIA), a disease caused by equine infectious anemia virus (EIAV), is considered an obstacle to the development of the horse industry. There is no treatment or vaccine available for EIA, and its pathogenesis, as well as the immune response against the virus, is not fully understood. Therefore, an immunohistochemistry assay was developed for the detection of viral antigens in tissues of equids naturally infected with EIAV. Sections of organs of six equids from Apodi-RN, Brazil, that tested positive for EIA by serological tests (ELISA and AGID) were fixed in 10% formalin solution and embedded in paraffin. Immunohistochemistry was performed using a polyclonal anti-EIAV antibody. EIAV antigens were observed in red spleen pulp cells and hepatic sinusoids, as well as bronchiolar and alveolar epithelial cells of the lungs and proximal and distal tubules of the kidneys. The presence of EIAV in the spleen and liver was expected due to viral tropism by macrophages, which are abundantly present in these organs. However, EIAV was also found in lung and kidney epithelial cells, indicating that the virus infects cell types other than macrophages. In conclusion, the immunohistochemical assay standardized in this study was able to detect EIAV antigens in spleen, liver, kidney and lung cells from naturally infected EIAV equids. Immunostaining observed in the spleen confirms viral tropism by mononuclear phagocytes; however, the presence of EIAV in lung and kidney epithelial cells indicates that virus may be eliminated in urine and/or oronasal secretions, suggesting new routes for viral excretion.
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Dorey-Robinson DLW, Locker N, Steinbach F, Choudhury B. Molecular characterization of equine infectious anaemia virus strains detected in England in 2010 and 2012. Transbound Emerg Dis 2019; 66:2311-2317. [PMID: 31267701 DOI: 10.1111/tbed.13286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 06/05/2019] [Accepted: 06/25/2019] [Indexed: 12/24/2022]
Abstract
Equine infectious anaemia virus (EIAV) is a retrovirus with worldwide distribution which is notifiable to the OIE. Despite its importance to the equine industry, most information regarding its biology have been obtained using only two strains (EIAVWYO and EIAVLIA ) from the USA and China, respectively. Recently full genome sequences from Ireland, Italy and Japan have been published; however, this is still not representative of the number of EIAV outbreaks experienced globally each year. The limited availability of published sequences makes design of a universal EIAV PCR difficult, hence diagnosis is solely reliant on serology. Accordingly, it is important to further investigate the re-emerging cases in other areas of the world. Here, we provide information regarding the outbreaks of EIA in England in 2010 and 2012 including the molecular characterization of strains. Full genome was obtained for two symptomatic cases but could not be resolved for the asymptomatic cases. The two British genomes from 2010 (EIAVDEV ) and 2012 (EIAVCOR ) each represent a new phylogenetic group, each differing genetically from the other available full genome sequences by 21.1%-25.5%. That the majority of new EIAV full genome sequences to be published adds another phylogenetic group indicates that the surface of EIAV global diversity is just being scratched. These data highlight that further work is needed to fully understand EIAV genetic diversity, namely the full genome sequencing of EIAV cases from a variety of locations and time points. This would aid both the use of phylogenetics in parallel with horse tracing as the epidemiological tool of disease tracking and the design of a universally applicable molecular diagnostic method.
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Affiliation(s)
| | | | - Falko Steinbach
- Animal & Plant Health Agency, Addlestone, UK.,University of Surrey, Guildford, UK
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Cook RF, Barrandeguy M, Lee PYA, Tsai CF, Shen YH, Tsai YL, Chang HFG, Wang HTT, Balasuriya UBR. Rapid detection of equine infectious anaemia virus nucleic acid by insulated isothermal RT-PCR assay to aid diagnosis under field conditions. Equine Vet J 2018; 51:489-494. [PMID: 30353944 DOI: 10.1111/evj.13032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/24/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Control of equine infectious anaemia (EIA) currently depends on serological diagnosis of infected equids. However, recently infected equids may not produce detectable anti-EIAV antibodies up to 157 days post infection and so present a high transmission risk. Therefore, direct nucleic acid detection methods are urgently needed to improve EIAV surveillance and management programs in counties where the disease is endemic. OBJECTIVES To evaluate a field-deployable, reverse transcription-insulated isothermal PCR (RT-iiPCR) assay targeting the conserved 5' untranslated region (5' UTR)/exon 1 of the tat gene of EIAV. STUDY DESIGN The analytical and clinical performance of the newly developed EIAV RT-iiPCR was evaluated by comparison with a EIAV real-time RT-PCR (RT-qPCR) along with the AGID test. METHODS Analytical sensitivity was determined using in vitro transcribed RNA containing the target area of the 5' UTR/tat gene and samples from two EIAV-positive horses. Specificity was verified using nine common equine viruses. Clinical performance was evaluated by comparison with EIAV RT-qPCR and AGID using samples derived from 196 inapparent EIAV carrier horses. RESULTS EIAV RT-iiPCR did not react with other commonly encountered equine viruses and had equivalent sensitivity (95% detection limit of eight genome equivalents), with a concordance of 95.41% to conventional EIAV RT-qPCR. However, the RT-qPCR and RT-iiPCR had sensitivities of 43.75 and 50.00%, respectively, when compared to the AGID test. MAIN LIMITATIONS Low viral loads commonly encountered in inapparent EIAV carriers may limit the diagnostic sensitivity of RT-PCR-based tests. CONCLUSIONS Although EIAV RT-iiPCR is not sufficiently sensitive to replace the current AGID test, it can augment control efforts by identifying recently exposed or "serologically silent" equids, particularly as the latter often represent a significant transmission risk because of high viral loads. Furthermore, the relatively low cost and field-deployable design enable utilisation of EIAV RT-iiPCR even in remote regions.
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Affiliation(s)
- R F Cook
- Louisiana Animal Disease Diagnostic Laboratory and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - M Barrandeguy
- Instituto Nacional de Tecnología Agropecuaria (INTA), Instituto de Virología, Argentina
| | - P-Y A Lee
- GeneReach USA, Lexington, Massachusetts, USA
| | - C-F Tsai
- GeneReach USA, Lexington, Massachusetts, USA
| | - Y-H Shen
- GeneReach USA, Lexington, Massachusetts, USA
| | - Y-L Tsai
- GeneReach USA, Lexington, Massachusetts, USA
| | - H-F G Chang
- GeneReach USA, Lexington, Massachusetts, USA
| | - H-T T Wang
- GeneReach USA, Lexington, Massachusetts, USA
| | - U B R Balasuriya
- Louisiana Animal Disease Diagnostic Laboratory and Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
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Cursino AE, Vilela APP, Franco-Luiz APM, de Oliveira JG, Nogueira MF, Júnior JPA, de Aguiar DM, Kroon EG. Equine infectious anemia virus in naturally infected horses from the Brazilian Pantanal. Arch Virol 2018; 163:2385-2394. [DOI: 10.1007/s00705-018-3877-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 03/19/2018] [Indexed: 10/16/2022]
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7
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Detection of equine infectious anemia nucleic acid in asymptomatic carrier horses by nested PCR. ASIAN BIOMED 2018. [DOI: 10.2478/abm-2010-0129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Background: Equine infectious anemia virus (EIAV) is a lentivirus with an almost worldwide distribution, infecting equids. It causes a persistent infection that is characterized by recurring episodes of fever, anemia, and thrombocytopenia. Most of the horses may control EIAV replication within a year, remaining persistently infected without clinical signs of disease. Objective: Detect EIA nucleic acid from peripheral blood of asymptomatic horses using nested PCR. Materials and method: We used nested PCR, amplifying P26 gag gene of EIAV, for direct detection of viral RNA in plasma and proviral DNA from PBMC in asymptomatic carrier horses in comparison with the Coggins test. EIA nucleic acid was prepared from 20 seropositive and five EIAV seronegative horses. Amplification of 246 bp expected size fragments was obtained using two different sets of primers targeting the P26 gag gene. Results: Among 20 seropositive horses, nine samples were positive for RNA and DNA. The five samples were positive for DNA but not for RNA, which indicates that the virus integrated into the host cell genome with a low level of viral replication. However, six samples were negative for both DNA and RNA. False negative could result due to primer failure caused by gag sequences variation among strains circulating in Thailand when compared with various strains from other parts of the world. EIAV antigens may also be prepared from cell cultures contaminated with other retroviruses thus causing false positives with the Coggins test. Conclusion: Nested PCR can be a useful tool for detecting the presence of EIAV in asymptomatic carrier horses. This may be especially true during the acute stage of the disease where the viremia levels are usually at the highest levels before detectable antibodies appear.
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Schwartz EJ, Vaidya NK, Dorman KS, Carpenter S, Mealey RH. Dynamics of lentiviral infection in vivo in the absence of adaptive immune responses. Virology 2017; 513:108-113. [PMID: 29055819 DOI: 10.1016/j.virol.2017.09.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 11/25/2022]
Abstract
Understanding the dynamics of acute viral infection is crucial for developing strategies to prevent and control infection. In this study, lentiviral dynamics in a host without adaptive immunity were examined in order to determine kinetic parameters of infection and quantify the effect of neutralizing antibodies in preventing infection, using mathematical modeling of data from equine infectious anemia virus (EIAV) infection of horses with severe combined immunodeficiency (SCID). Estimated parameters were used to calculate the basic reproductive number and virus doubling time and found that the rate that antibodies neutralized virus was ~18 times greater than the virus clearance rate. These results establish EIAV replication kinetics in SCID horses and the minimal efficacy of antibodies that blocked infection. Furthermore, they indicate that EIAV is at most mildly cytopathic. This study advances our understanding of EIAV infection and may have important implications for the control of other viral infections, including HIV.
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Affiliation(s)
- Elissa J Schwartz
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA; Department of Mathematics and Statistics, Washington State University, Pullman, WA 99164, USA.
| | - Naveen K Vaidya
- Department of Mathematics and Statistics, San Diego State University, San Diego, CA 92182, USA
| | - Karin S Dorman
- Department of Statistics, Iowa State University, Ames, IA 50011, USA; Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Susan Carpenter
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA
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Gaudaire D, Lecouturier F, Ponçon N, Morilland E, Laugier C, Zientara S, Hans A. Molecular characterization of equine infectious anaemia virus from a major outbreak in southeastern France. Transbound Emerg Dis 2017; 65:e7-e13. [PMID: 28503813 DOI: 10.1111/tbed.12657] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Indexed: 12/25/2022]
Abstract
In 2009, a major outbreak of equine infectious anaemia (EIA) was reported in the south-east of France. This outbreak affected three premises located in the Var region where the index case, a 10-year-old mare that exhibited clinical signs consistent with EIA, occurred at a riding school. Overall, more than 250 horses were tested for EIAV (equine infectious anaemia virus) antibodies, using agar gel immunodiffusion test, and 16 horses were positive in three different holdings. Epidemiological survey confirmed that the three premises were related through the purchase/sale of horses and the use of shared or nearby pastures. Molecular characterization of viruses was performed by sequencing the full gag gene sequence (1,400 bp) of the proviral DNAs retrieved from the spleen of infected animals collected post-mortem. Phylogenetic analysis confirmed epidemiological data from the field, as viruses isolated from the three premises were clustering together suggesting a common origin whereas some premises were 50 km apart. Moreover, viruses characterized during this outbreak are different from European strains described so far, underlying the high genetic diversity of EIAV in Europe.
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Affiliation(s)
- D Gaudaire
- Virology Unit, ANSES-Dozulé Laboratory for Equine Diseases, Goustranville, France
| | - F Lecouturier
- Virology Unit, ANSES-Dozulé Laboratory for Equine Diseases, Goustranville, France
| | - N Ponçon
- Direction Générale de l'Alimentation, Ministère de l'Agriculture, Paris, France
| | - E Morilland
- Virology Unit, ANSES-Dozulé Laboratory for Equine Diseases, Goustranville, France
| | - C Laugier
- Virology Unit, ANSES-Dozulé Laboratory for Equine Diseases, Goustranville, France
| | - S Zientara
- Anses Maisons-Alfort Laboratory for Animal Health, UMR1161 Virologie, Université Paris-Est, Maisons-Alfort, France
| | - A Hans
- Virology Unit, ANSES-Dozulé Laboratory for Equine Diseases, Goustranville, France
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Cappelli K, Cook RF, Stefanetti V, Passamonti F, Autorino GL, Scicluna MT, Coletti M, Verini Supplizi A, Capomaccio S. Deep sequencing and variant analysis of an Italian pathogenic field strain of equine infectious anaemia virus. Transbound Emerg Dis 2017; 64:2104-2112. [DOI: 10.1111/tbed.12631] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Indexed: 11/28/2022]
Affiliation(s)
- K. Cappelli
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
| | - R. F. Cook
- Department of Veterinary Science; Gluck Equine Research Center; University of Kentucky; Lexington KY USA
| | - V. Stefanetti
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
| | - F. Passamonti
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
| | - G. L. Autorino
- Istituto Zooprofilattico Sperimentale delle Regioni Lazio e Toscana; Rome Italy
| | - M. T. Scicluna
- Istituto Zooprofilattico Sperimentale delle Regioni Lazio e Toscana; Rome Italy
| | - M. Coletti
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
| | - A. Verini Supplizi
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
| | - S. Capomaccio
- Dipartimento di Medicina Veterinaria - Centro di Studio del Cavallo Sportivo; Università degli Studi di Perugia; Perugia Italy
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Amino acid mutations in the env gp90 protein that modify N-linked glycosylation of the Chinese EIAV vaccine strain enhance resistance to neutralizing antibodies. Virus Genes 2016; 52:814-822. [PMID: 27572122 DOI: 10.1007/s11262-016-1382-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/12/2016] [Indexed: 02/05/2023]
Abstract
The Chinese EIAV vaccine is an attenuated live virus vaccine obtained by serial passage of a virulent horse isolate (EIAVL) in donkeys (EIAVD) and, subsequently, in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAVL) with attenuated strains serially passaged in donkey MDM (EIAVDLV) and donkey dermal cells (EIAVFDDV). 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 EIAVFDDV 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 EIAVFDDV. 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. This study indicates that these mutations played an important role in the attenuation of the EIAV vaccine strains.
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Ricotti S, Garcia MI, Veaute C, Bailat A, Lucca E, Cook RF, Cook SJ, Soutullo A. Serologically silent, occult equine infectious anemia virus (EIAV) infections in horses. Vet Microbiol 2016; 187:41-49. [DOI: 10.1016/j.vetmic.2016.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 03/07/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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Evolution of equine infectious anaemia in naturally infected mules with different serological reactivity patterns prior and after immune suppression. Vet Microbiol 2016; 189:15-23. [PMID: 27259822 DOI: 10.1016/j.vetmic.2016.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/25/2016] [Accepted: 04/04/2016] [Indexed: 11/21/2022]
Abstract
Information on equine infectious anaemia (EIA) in mules, including those with an equivocal reaction in agar gel immunodiffusion test (AGIDT), is scarce. For this, a study was conducted to evaluate the clinical, viral loads and pathological findings of two groups of naturally infected asymptomatic mules, respectively with a negative/equivocal and positive AGIDT reactivity, which were subjected to pharmacological immune suppression (IS). A non-infected control was included in the study that remained negative during the observation period. Throughout the whole study, even repeated episodes of recrudescence of EIA were observed in 9 infected mules, independently from their AGIDT reactivity. These events were generally characterised by mild, transient alterations, typical of the EIA acute form represented by hyperthermia and thrombocytopenia, in concomitance with viral RNA (vRNA) peaks that were higher in the Post-IS period, reaching values similar to those of horses during the clinical acute phase of EIA. Total tissue viral nucleic acid loads were greatest in animals with the major vRNA activity and in particular in those with negative/equivocal AGIDT reactivity. vRNA replication levels were around 10-1000 times lower than those reported in horses, with the animals still presenting typical alterations of EIA reactivation. Macroscopic lesions were absent in all the infected animals while histological alterations were characterised by lymphomonocyte infiltrates and moderate hemosiderosis in the cytoplasm of macrophages. On the basis of the above results, even mules with an equivocal/negative AGIDT reaction may act as EIAV reservoirs. Moreover, such animals could escape detection due to the low AGIDT sensitivity and therefore contribute to the maintenance and spread of the infection.
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Liu Q, Ma J, Wang XF, Xiao F, Li LJ, Zhang JE, Lin YZ, Du C, He XJ, Wang X, Zhou JH. Infection with equine infectious anemia virus vaccine strain EIAVDLV121 causes no visible histopathological lesions in target organs in association with restricted viral replication and unique cytokine response. Vet Immunol Immunopathol 2016; 170:30-40. [PMID: 26832985 PMCID: PMC7112881 DOI: 10.1016/j.vetimm.2016.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 11/10/2015] [Accepted: 01/20/2016] [Indexed: 11/06/2022]
Abstract
The live equine infectious anemia virus (EIAV) vaccine strain EIAVDLV121 was developed by in vitro attenuation of a virulent strain, EIAVLN40, in the 1970s, and it has been demonstrated to induce protective immunity under laboratory and natural EIAV infection conditions. The detailed biological features of this attenuated virus remain to be further investigated. Experimental inoculation with EIAVDLV121 did not result in clinical symptoms even with immunosuppressive treatment in our previous studies. Here, we further investigated whether the replication of the vaccine strain EIAVDLV121 in experimentally infected horses causes histopathological lesions to develop in the targeted organs. Both the lungs and the spleen have been demonstrated to support EIAV replication. By evaluating the gross macroscopic and histological changes, we found that EIAVDLV121 did not cause detectable histopathological lesions and that it replicated several hundred times more slowly than its parental virulent strain, EIAVLN40, in tissues. Immunochemical assays of these tissues indicated that the primary target cells of EIAVDLV121 were monocytes/macrophages, but that EIAVLN40 also infected alveolar epithelial cells and vascular endothelial cells. In addition, both of these viral strains promoted the up- and down-regulation of the expression of various cytokines and chemokines, implicating the potential involvement of these cellular factors in the pathological outcomes of EIAV infection and host immune responses. Taken together, these results demonstrate that the EIAV vaccine strain does not cause obvious histopathological lesions or clinical symptoms and that it induces a unique cytokine response profile. These features are considered essential for EIAVDLV121 to function as an effective live vaccine.
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Affiliation(s)
- Qiang Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Jian Ma
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Fei Xiao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Li-Jia Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Jiao-Er Zhang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Yue-Zhi Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Cheng Du
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
| | - Xi-Jun He
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China.
| | - Xiaojun Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China.
| | - Jian-Hua Zhou
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China; Harbin Pharmaceutical Group Biovaccine Company, Harbin 150069, China.
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15
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Characterization of Equine Infectious Anemia Virus Integration in the Horse Genome. Viruses 2015; 7:3241-60. [PMID: 26102582 PMCID: PMC4488736 DOI: 10.3390/v7062769] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/12/2015] [Accepted: 06/15/2015] [Indexed: 01/17/2023] Open
Abstract
Human immunodeficiency virus (HIV)-1 has a unique integration profile in the human genome relative to murine and avian retroviruses. Equine infectious anemia virus (EIAV) is another well-studied lentivirus that can also be used as a promising retro-transfection vector, but its integration into its native host has not been characterized. In this study, we mapped 477 integration sites of the EIAV strain EIAVFDDV13 in fetal equine dermal (FED) cells during in vitro infection. Published integration sites of EIAV and HIV-1 in the human genome were also analyzed as references. Our results demonstrated that EIAVFDDV13 tended to integrate into genes and AT-rich regions, and it avoided integrating into transcription start sites (TSS), which is consistent with EIAV and HIV-1 integration in the human genome. Notably, the integration of EIAVFDDV13 favored long interspersed elements (LINEs) and DNA transposons in the horse genome, whereas the integration of HIV-1 favored short interspersed elements (SINEs) in the human genome. The chromosomal environment near LINEs or DNA transposons potentially influences viral transcription and may be related to the unique EIAV latency states in equids. The data on EIAV integration in its natural host will facilitate studies on lentiviral infection and lentivirus-based therapeutic vectors.
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16
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Du C, Ma J, Liu Q, Li YF, He XJ, Lin YZ, Wang XF, Meng QW, Wang X, Zhou JH. Mice transgenic for equine cyclin T1 and ELR1 are susceptible to equine infectious anemia virus infection. Retrovirology 2015; 12:36. [PMID: 25928027 PMCID: PMC4422544 DOI: 10.1186/s12977-015-0163-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/02/2015] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND As a member of the tumor necrosis factor receptor (TNFR) protein superfamily, equine lentivirus receptor 1 (ELR1) has been shown to be expressed in various equine cells that are permissive for equine infectious anemia virus (EIAV) replication. The EIAV Tat protein (eTat) activates transcription initiated at the viral long terminal repeat (LTR) promoter through a unique mechanism that requires the recruitment of the equine cyclin T1 (eCT1) cofactor into the viral TAR RNA target element. In vitro studies have demonstrated that mouse fibroblast cell lines (e.g., NIH 3T3 cells) that express the EIAV receptor ELR1 and eCT1 support the productive replication of EIAV. Therefore, we constructed transgenic eCT1- and ELR1-expressing mice to examine whether they support in vivo EIAV replication. FINDINGS For the first time, we constructed mice transgenic for ELR1 and eCT1. Real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis confirmed that ELR1 and eCT1 were expressed in the transgenic mouse tissues, particularly in the intestines, spleen and lymph nodes. Consistent with the results of EIAV infection in NIH 3T3 cells expressing ELR1 and eCT1, mouse embryonic fibroblasts (MEFs) from the transgenic mice could support EIAV replication. More importantly, this virus could infect and replicate in mouse blood monocyte-derived macrophages (mMDMs). Macrophages are the principle target cell of EIAV in its natural hosts. Furthermore, after the transgenic mice were inoculated with EIAV, the virus could be detected not only in the plasma of the circulating blood but also in multiple organs, among which, the spleen and lymph nodes were the predominant sites of EIAV replication. Finally, we found that consistent with high viral replication levels, the relevant pathological changes occurred in the spleen and lymph nodes. CONCLUSIONS Our results show that mice transgenic for ELR1 and eCT1 are susceptible to EIAV infection and replication. Further, EIAV infection can cause lesions on the spleen and lymph nodes, similar to those frequently observed in horses, the natural hosts. Therefore, ELR1 and eCT1 are essential in vivo for EIAV invasion and replication.
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Affiliation(s)
- Cheng Du
- 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, 150001, China.
| | - Jian Ma
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Qiang Liu
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Yun-Fei Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Xi-Jun He
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Yue-Zhi Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Xue-Feng Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, 150001, China.
| | - Qing-Wen Meng
- 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.
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17
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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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18
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Liu C, Cook SJ, Craigo JK, Cook FR, Issel CJ, Montelaro RC, Horohov DW. Epitope shifting of gp90-specific cellular immune responses in EIAV-infected ponies. Vet Immunol Immunopathol 2014; 161:161-9. [PMID: 25176006 DOI: 10.1016/j.vetimm.2014.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/02/2014] [Accepted: 08/04/2014] [Indexed: 11/16/2022]
Abstract
Unlike other lentiviruses, EIAV replication can be controlled in most infected horses leading to an inapparent carrier state free of overt clinical signs which lasts for many years. While the resolution of the initial infection is correlated with the appearance of virus specific cellular immune responses, the precise immune mechanisms responsible for control of the infection are not yet identified. Since the virus undergoes rapid mutation following infection, the immune response must also adapt to meet this challenge. We hypothesize that this adaptation involves peptide-specific recognition shifting from immunodominant variable determinants to conserved immunorecessive determinants following EIAV infection. Forty-four peptides, spanning the entire surface unit protein (gp90) of EIAV, were used to monitor peptide-specific T cell responses in vivo over a six-month period following infection. Peptides were injected intradermally and punch biopsies were collected for real-time PCR analysis to monitor the cellular peptide-specific immune responses in vivo. Similar to the CMI response to HIV infection, peptide-specific T cell recognition patterns changed over time. Early post infection (1 month), immune responses were directed to the peptides in the carboxyl-terminus variable region. By six months post infection, the peptide recognition spanned the entire gp90 sequence. These results indicate that peptide recognition broadens during EIAV infection.
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Affiliation(s)
- Chong Liu
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Sheila J Cook
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Jodi K Craigo
- Center for Vaccine Research and Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Frank R Cook
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Charles J Issel
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA
| | - Ronald C Montelaro
- Center for Vaccine Research and Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA
| | - David W Horohov
- Department of Veterinary Science, University of Kentucky, Lexington, KY, USA.
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19
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Ma J, Wang SS, Lin YZ, Liu HF, Liu Q, Wei HM, Wang XF, Wang YH, Du C, Kong XG, Zhou JH, Wang X. Infection of equine monocyte-derived macrophages with an attenuated equine infectious anemia virus (EIAV) strain induces a strong resistance to the infection by a virulent EIAV strain. Vet Res 2014; 45:82. [PMID: 25106750 PMCID: PMC4283155 DOI: 10.1186/s13567-014-0082-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 07/23/2014] [Indexed: 11/10/2022] Open
Abstract
The Chinese attenuated equine infectious anemia virus (EIAV) vaccine has successfully protected millions of equine animals from EIA disease in China. Given that the induction of immune protection results from the interactions between viruses and hosts, a better understanding of the characteristics of vaccine strain infection and host responses would be useful for elucidating the mechanism of the induction of immune protection by the Chinese attenuated EIAV strain. In this study, we demonstrate in equine monocyte-derived macrophages (eMDM) that EIAVFDDV13, a Chinese attenuated EIAV strain, induced a strong resistance to subsequent infection by a pathogenic strain, EIAVUK3. Further experiments indicate that the expression of the soluble EIAV receptor sELR1, Toll-like receptor 3 (TLR3) and interferon β (IFNβ) was up-regulated in eMDM infected with EIAVFDDV13 compared with eMDM infected with EIAVUK3. Stimulating eMDM with poly I:C resulted in similar resistance to EIAV infection as induced by EIAVFDDV13 and was correlated with enhanced TLR3, sELR1 and IFNβ expression. The knock down of TLR3 mRNA significantly impaired poly I:C-stimulated resistance to EIAV, greatly reducing the expression of sELR1 and IFNβ and lowered the level of infection resistance induced by EIAVFDDV13. These results indicate that the induction of restraining infection by EIAVFDDV13 in macrophages is partially mediated through the up-regulated expression of the soluble viral receptor and IFNβ, and that the TLR3 pathway activation plays an important role in the development of an EIAV-resistant intracellular environment.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Jian-Hua Zhou
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, Heilongjiang, China.
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20
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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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21
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Bolfa P, Nolf M, Cadoré JL, Catoi C, Archer F, Dolmazon C, Mornex JF, Leroux C. Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses. Vet Res 2013; 44:113. [PMID: 24289102 PMCID: PMC3879148 DOI: 10.1186/1297-9716-44-113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Accepted: 11/12/2013] [Indexed: 11/29/2022] Open
Abstract
EIA (Equine Infectious Anemia) is a blood-borne disease primarily transmitted by haematophagous insects or needle punctures. Other routes of transmission have been poorly explored. We evaluated the potential of EIAV (Equine Infectious Anemia Virus) to induce pulmonary lesions in naturally infected equids. Lungs from 77 EIAV seropositive horses have been collected in Romania and France. Three types of lesions have been scored on paraffin-embedded lungs: lymphocyte infiltration, bronchiolar inflammation, and thickness of the alveolar septa. Expression of the p26 EIAV capsid (CA) protein has been evaluated by immunostaining. Compared to EIAV-negative horses, 52% of the EIAV-positive horses displayed a mild inflammation around the bronchioles, 22% had a moderate inflammation with inflammatory cells inside the wall and epithelial bronchiolar hyperplasia and 6.5% had a moderate to severe inflammation, with destruction of the bronchiolar epithelium and accumulation of smooth muscle cells within the pulmonary parenchyma. Changes in the thickness of the alveolar septa were also present. Expression of EIAV capsid has been evidenced in macrophages, endothelial as well as in alveolar and bronchiolar epithelial cells, as determined by their morphology and localization. To summarize, we found lesions of interstitial lung disease similar to that observed during other lentiviral infections such as FIV in cats, SRLV in sheep and goats or HIV in children. The presence of EIAV capsid in lung epithelial cells suggests that EIAV might be responsible for the broncho-interstitial damages observed.
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Affiliation(s)
| | | | | | | | | | | | | | - Caroline Leroux
- UMR754, Retrovirus and Comparative Pathology, INRA, Lyon, France.
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22
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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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23
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Kuhar U, Završnik J, Toplak I, Malovrh T. Detection and molecular characterisation of equine infectious anaemia virus from field outbreaks in Slovenia. Equine Vet J 2013; 46:386-91. [DOI: 10.1111/evj.12138] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- U. Kuhar
- Veterinary Faculty; Institute for Microbiology and Parasitology; Virology Unit; University of Ljubljana; Slovenia
| | - J. Završnik
- Veterinary Faculty; Institute for Microbiology and Parasitology; Virology Unit; University of Ljubljana; Slovenia
| | - I. Toplak
- Veterinary Faculty; Institute for Microbiology and Parasitology; Virology Unit; University of Ljubljana; Slovenia
| | - T. Malovrh
- Veterinary Faculty; Institute for Microbiology and Parasitology; Virology Unit; University of Ljubljana; Slovenia
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24
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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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25
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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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26
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Dong JB, Zhu W, Cook FR, Goto Y, Horii Y, Haga T. Identification of a novel equine infectious anemia virus field strain isolated from feral horses in southern Japan. J Gen Virol 2013; 94:360-365. [DOI: 10.1099/vir.0.047498-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although equine infectious anemia (EIA) was described more than 150 years ago, complete genomic sequences have only been obtained from two field strains of EIA virus (EIAV), EIAVWyoming and EIAVLiaoning. In 2011, EIA was detected within the distinctive feral Misaki horse population that inhabits the Toi-Cape area of southern Japan. Complete proviral sequences comprising a novel field strain were amplified directly from peripheral blood of one of these EIAV-infected horses and characterized by nucleotide sequencing. The complete provirus of Miyazaki2011-A strain is 8208 bp in length with an overall genomic organization typical of EIAV. However, this field isolate possesses just 77.2 and 78.7 % nucleotide sequence identity with the EIAVWyoming and EIAVLiaoning strains, respectively, while similarity plot analysis suggested all three strains arose independently. Furthermore, phylogenetic studies using sequences obtained from all EIAV-infected Misaki horses against known viral strains strongly suggests these Japanese isolates comprise a separate monophyletic group.
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Affiliation(s)
- Jian-Bao Dong
- The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8511, Japan
- Research Fellow DC of the Japan Society for the Promotion of Science, Tokyo 102-8472, Japan
- Departments of Veterinary Microbiology, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Wei Zhu
- Research Fellow DC of the Japan Society for the Promotion of Science, Tokyo 102-8472, Japan
- Departments of Veterinary Microbiology, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Frank R. Cook
- Gluck Equine Research Center, Department of Veterinary Science, University of Kentucky, Lexington, KY 40506, USA
| | - Yoshitaka Goto
- Departments of Veterinary Microbiology, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Yoichiro Horii
- Veterinary Parasitic Diseases, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Takeshi Haga
- Division of Infection Control and Disease Prevention, Department of Veterinary Medical Science, University of Tokyo, Tokyo 113-8654, Japan
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27
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Schwartz EJ, Pawelek KA, Harrington K, Cangelosi R, Madrid S. Immune Control of Equine Infectious Anemia Virus Infection by Cell-Mediated and Humoral Responses. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/am.2013.48a023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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28
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Caij AB, Tignon M. Epidemiology and Genetic Characterization of Equine Infectious Anaemia Virus Strains Isolated in Belgium in 2010. Transbound Emerg Dis 2012; 61:464-8. [DOI: 10.1111/tbed.12031] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Indexed: 11/26/2022]
Affiliation(s)
- A. B. Caij
- Unit Enzootic and (Re-) Emerging Viral Disease; Operational Direction of Viral Diseases; Veterinary and Agrochemical Research Centre; Brussels Belgium
| | - M. Tignon
- Unit Enzootic and (Re-) Emerging Viral Disease; Operational Direction of Viral Diseases; Veterinary and Agrochemical Research Centre; Brussels Belgium
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29
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Craigo JK, Ezzelarab C, Montelaro RC. Development of a high throughput, semi-automated, infectious center cell-based ELISA for equine infectious anemia virus. J Virol Methods 2012; 185:221-7. [PMID: 22820072 DOI: 10.1016/j.jviromet.2012.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 06/28/2012] [Accepted: 07/04/2012] [Indexed: 11/26/2022]
Abstract
A faster semi-automated 96-well microtiter plate assay to determine viral infectivity titers, or viral focal units (vfu), of equine infectious anemia virus (EIAV) stocks is described. Optimization of the existing method modernizes a classic virological technique for viral titer determination by quantitating EIAV in experimentally infected cells via a cell-based ELISA. To allow for automation, multiple parameters of the current assay procedures were modified resulting in an assay that required only one quarter the original amount of virus and/or serum for infectivity or neutralization assays, respectively. Equivalent reductions in the required volumes of tissue culture, cell processing, and protein detection reagents were also achieved. Additionally, the new assay decreased the time required from start to finish from 10 days to 6 days (viral titer) or 7 days (viral neutralization), while increasing the number of samples that can be processed concurrently by transition to a 96-well microtiter plate format and by automated counting.
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Affiliation(s)
- Jodi K Craigo
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Development of a nested PCR assay to detect equine infectious anemia proviral DNA from peripheral blood of naturally infected horses. Arch Virol 2012; 157:2105-11. [PMID: 22798044 DOI: 10.1007/s00705-012-1406-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 05/25/2012] [Indexed: 10/28/2022]
Abstract
Equine infectious anemia (EIA) has posed a major challenge and caused significant losses to the equine industry worldwide. PCR detection methods have considerable potential as an adjunct to conventional serological diagnostic techniques. However, most published PCR methods, including that recommended by the OIE, were designed using laboratory-adapted virus strains and do not function with field isolates of EIA virus (EIAV). In the present study, a nested PCR assay for detection of EIAV proviral DNA in peripheral blood cells of naturally infected horses was developed. Primer sets were designed based on conserved 5' regions of the viral genome extending from the LTR to the tat gene. Preliminary studies demonstrated that the method has a detection limit of 10 genomic copies and, when applied to a naturally EIAV-infected feral horse population, shows 100 % correlation with conventional serological diagnostic techniques. This assay provides a powerful new tool in the control of EIAV.
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Patel JR, Heldens JGM, Bakonyi T, Rusvai M. Important mammalian veterinary viral immunodiseases and their control. Vaccine 2012; 30:1767-81. [PMID: 22261411 PMCID: PMC7130670 DOI: 10.1016/j.vaccine.2012.01.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 01/03/2012] [Accepted: 01/05/2012] [Indexed: 11/16/2022]
Abstract
This paper offers an overview of important veterinary viral diseases of mammals stemming from aberrant immune response. Diseases reviewed comprise those due to lentiviruses of equine infectious anaemia, visna/maedi and caprine arthritis encephalitis and feline immunodeficiency. Diseases caused by viruses of feline infectious peritonitis, feline leukaemia, canine distemper and aquatic counterparts, Aleutian disease and malignant catarrhal fever. We also consider prospects of immunoprophylaxis for the diseases and briefly other control measures. It should be realised that the outlook for effective vaccines for many of the diseases is remote. This paper describes the current status of vaccine research and the difficulties encountered during their development.
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Affiliation(s)
- J R Patel
- Jas Biologicals Ltd, 12 Pembroke Avenue, Denny Industrial Estate, Waterbeach, Cambridge CB25 9QR, UK.
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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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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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Molecular detection, epidemiology, and genetic characterization of novel European field isolates of equine infectious anemia virus. J Clin Microbiol 2010; 49:27-33. [PMID: 21084503 DOI: 10.1128/jcm.01311-10] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The application of molecular diagnostic techniques along with nucleotide sequence determination to permit contemporary phylogenetic analysis of European field isolates of equine infectious anemia virus (EIAV) has not been widely reported. As a result, of extensive testing instigated following the 2006 outbreak of equine infectious anemia in Italy, 24 farms with a history of exposure to this disease were included in this study. New PCR-based methods were developed, which, especially in the case of DNA preparations from peripheral blood cells, showed excellent correlation with OIE-approved agar gel immunodiffusion (AGID) tests for identifying EIAV-infected animals. In contrast, the OIE-recommended oligonucleotide primers for EIAV failed to react with any of the Italian isolates. Similar results were also obtained with samples from four Romanian farms. In addition, for the first time complete characterization of gag genes from five Italian isolates and one Romanian isolate has been achieved, along with acquisition of extensive sequence information (86% of the total gag gene) from four additional EIAV isolates (one Italian and three Romanian). Furthermore, in another 23 cases we accomplished partial characterization of gag gene sequences in the region encoding the viral matrix protein. Analysis of this information suggested that most Italian isolates were geographically restricted, somewhat reminiscent of the "clades" described for human immunodeficiency virus type 1 (HIV-1). Collectively this represents the most comprehensive genetic study of European EIAV isolates conducted to date.
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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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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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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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McNab T, Desport M, Tenaya WM, Hartaningsih N, Wilcox GE. Bovine immunodeficiency virus produces a transient viraemic phase soon after infection in Bos javanicus. Vet Microbiol 2009; 141:216-23. [PMID: 19766411 DOI: 10.1016/j.vetmic.2009.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 08/06/2009] [Accepted: 09/04/2009] [Indexed: 02/05/2023]
Abstract
Infection of Bali cattle (Bos javanicus) in Indonesia with a non-pathogenic bovine lentivirus similar to Bovine immunodeficiency virus (BIV) is suspected but efforts to detect the virus have been unsuccessful. To define the kinetics of BIV infection in Bali cattle, 13 were infected with the R-29 strain of BIV and monitored for 60 days. No clinical effects were detected. Proviral DNA was detected in peripheral blood mononuclear cells from 4 to 60 days with peak titres 20 days post-infection (dpi). There was a transient viraemia from 4 to 14 dpi with a maximum titre of 1x10(4)genome copies/ml plasma. An antibody response to the transmembrane (TM) glycoprotein commenced 12 dpi but an antibody response to the capsid (CA) protein was detected in one animal only and not until 34 dpi. The results indicated that detection of BIV in infected Bali cattle would have a greater chance of success soon after infection and prior to the onset of a CA antibody response.
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Affiliation(s)
- Tegan McNab
- School of Veterinary and Biomedical Science, Murdoch University, Murdoch, WA 6150, Australia
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Fidalgo-Carvalho I, Craigo JK, Barnes S, Costa-Ramos C, Montelaro RC. Characterization of an equine macrophage cell line: application to studies of EIAV infection. Vet Microbiol 2008; 136:8-19. [PMID: 19038510 DOI: 10.1016/j.vetmic.2008.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 10/06/2008] [Accepted: 10/13/2008] [Indexed: 11/26/2022]
Abstract
EIAV is a monocyte/macrophage tropic virus. To date, even though EIAV has been under investigation for numerous years, very few details have been elucidated about EIAV/macrophage interactions. This is largely due to the absence of an equine macrophage cell line that would support viral replication. Herein we describe the spontaneous immortalization and generation of a clonal equine macrophage-like (EML) cell line with the functional and immunophenotype characteristics of differentiated equine monocyte derived macrophage(s) (eMDM(s)). These cells possess strong non-specific esterase (NSE) activity, are able to phagocytose fluorescent bioparticles, and produce nitrites in response to LPS. The EML-3C cell line expresses the EIAV receptor for cellular entry (ELR1) and supports replication of the virulent EIAV(PV) biological clone. Thus, EML-3C cells provide a useful cell line possessing equine macrophage related properties for the growth and study of EIAV infection as well as of other equine macrophage tropic viruses.
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Affiliation(s)
- Isabel Fidalgo-Carvalho
- Iron Genes and the Immune System, Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, Oporto, Portugal
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Equine infectious anemia virus resists the antiretroviral activity of equine APOBEC3 proteins through a packaging-independent mechanism. J Virol 2008; 82:11889-901. [PMID: 18818324 DOI: 10.1128/jvi.01537-08] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Equine infectious anemia virus (EIAV), uniquely among lentiviruses, does not encode a vif gene product. Other lentiviruses, including human immunodeficiency virus type 1 (HIV-1), use Vif to neutralize members of the APOBEC3 (A3) family of intrinsic immunity factors that would otherwise inhibit viral infectivity. This suggests either that equine cells infected by EIAV in vivo do not express active A3 proteins or that EIAV has developed a novel mechanism to avoid inhibition by equine A3 (eA3). Here, we demonstrate that horses encode six distinct A3 proteins, four of which contain a single copy of the cytidine deaminase (CDA) consensus active site and two of which contain two CDA motifs. This represents a level of complexity previously seen only in primates. Phylogenetic analysis of equine single-CDA A3 proteins revealed two proteins related to human A3A (hA3A), one related to hA3C, and one related to hA3H. Both equine double-CDA proteins are similar to hA3F and were named eA3F1 and eA3F2. Analysis of eA3F1 and eA3F2 expression in vivo shows that the mRNAs encoding these proteins are widely expressed, including in cells that are natural EIAV targets. Both eA3F1 and eA3F2 inhibit retrotransposon mobility, while eA3F1 is a potent inhibitor of a Vif-deficient HIV-1 mutant and induces extensive editing of HIV-1 reverse transcripts. However, both eA3F1 and eA3F2 are weak inhibitors of EIAV. Surprisingly, eA3F1 and eA3F2 were packaged into EIAV and HIV-1 virions as effectively as hA3G, although only the latter inhibited EIAV infectivity. Moreover, all three proteins bound both the HIV-1 and EIAV nucleocapsid protein specifically in vitro. It therefore appears that EIAV has evolved a novel mechanism to specifically neutralize the biological activities of the cognate eA3F1 and eA3F2 proteins at a step subsequent to virion incorporation.
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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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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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Fraser DG, Leib SR, Zhang BS, Mealey RH, Brown WC, McGuire TC. Lymphocyte proliferation responses induced to broadly reactive Th peptides did not protect against equine infectious anemia virus challenge. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2005; 12:983-93. [PMID: 16085917 PMCID: PMC1182189 DOI: 10.1128/cdli.12.8.983-993.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effect of immunization with five lipopeptides, three containing T-helper (Th) epitopes and two with both Th and cytotoxic T-lymphocyte (CTL) epitopes, on equine infectious anemia virus (EIAV) challenge was evaluated. Peripheral blood mononuclear cells from EIAV lipopeptide-immunized horses had significant proliferative responses to Th peptides compared with those preimmunization, and the responses were attributed to significant responses to peptides Gag from positions 221 to 245 (Gag 221-245), Gag 250-269, and Pol 326-347; however, there were no consistent CTL responses. The significant proliferative responses in the EIAV lipopeptide-immunized horses allowed testing of the hypothesis that Th responses to immunization would enhance Th and CTL responses following EIAV challenge and lessen the viral load and the severity of clinical disease. The EIAV lipopeptide-immunized group did have a significant increase in proliferative responses to Th peptides 1 week after virus challenge, whereas the control group did not. Two weeks after challenge, a significant CTL response to virus-infected cell targets occurred in the EIAV lipopeptide-immunized group compared to that in the control group. These Th and CTL responses did not significantly alter either the number of viral RNA copies/ml or disease severity. Thus, lipopeptide-induced proliferative responses and enhanced Th and CTL responses early after virus challenge were unable to control challenge virus load and clinical disease.
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Affiliation(s)
- Darrilyn G Fraser
- Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA
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Craigo JK, Sturgeon TJ, Cook SJ, Issel CJ, Leroux C, Montelaro RC. Apparent elimination of EIAV ancestral species in a long-term inapparent carrier. Virology 2005; 344:340-53. [PMID: 16226288 DOI: 10.1016/j.virol.2005.09.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 08/10/2005] [Accepted: 09/07/2005] [Indexed: 11/18/2022]
Abstract
Equine infectious anemia virus (EIAV) envelope variation produces newly dominant quasispecies with each sequential disease cycle; new populations arise, and previous plasma quasispecies, including the original inoculum, become undetectable. The question remains whether these ancestral variants exist in tissue reservoirs or if the immune system eliminates quasispecies from persistent infections. To examine this, an EIAV long-term inapparent carrier was immune suppressed with dexamethasone. Immune suppression resulted in increased plasma viral loads by approximately 10(4) fold. Characterization of pre- and post-immune suppression populations demonstrated continual envelope evolution and revealed novel quasispecies distinct from defined populations from previous disease stages. Analysis of the tissue and plasma populations post-immune suppression indicated the original infectious inoculum and early populations were undetectable. Therefore, the host immune system apparently eliminated a diverse array of antigenic variants, but viral persistence was maintained by relentless evolution of new envelope populations from tissue reservoirs in response to ongoing immune pressures.
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Affiliation(s)
- Jodi K Craigo
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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45
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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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46
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Spyrou V, Papanastassopoulou M, Koumbati M, Nikolakaki SV, Koptopoulos G. Molecular analysis of the proviral DNA of equine infectious anemia virus in mules in Greece. Virus Res 2005; 107:63-72. [PMID: 15567035 DOI: 10.1016/j.virusres.2004.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 06/04/2004] [Accepted: 06/25/2004] [Indexed: 11/16/2022]
Abstract
Molecular analysis of the regulatory and structurally important genetic segments of equine infectious anemia virus (EIAV) in mules is presented. We have previously reported clinicopathological and laboratory findings in mules infected with EIAV, both naturally and after experimental inoculation. In this study the fragment coding for integrase, gp90, tat and the fusion domain of gp45 of the proviral genome from these animals was sequenced and compared with one another and with that of EIAV strains already published in the literature. Significant variations were observed mainly in the sequences of the gp90 surface protein. In the two wild type sequences, there were substitutions in the V5 hypervariable domain of this protein. In the sequences of the experimentally inoculated animals and the donor strain, variations were due to insertions/duplications in the V3 principal neutralizing domain (PND) and substitutions in the V5 hypervariable domain. Finally, when compared with the already published strains, the wild type sequences had single amino acid substitutions across the whole protein and multiple substitutions in the V4-V6 variable domains. In general, the two Greek wild type sequences were closer to two of the American strains (WSU5 and Massachusetts), than to the two Japanese (V26 and V70) or the third American strain (Wyoming_wi) used in this study.
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Affiliation(s)
- Vassiliki Spyrou
- Laboratory of Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece
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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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Oaks JL, Long MT, Baszler TV. Leukoencephalitis associated with selective viral replication in the brain of a pony with experimental chronic equine infectious anemia virus infection. Vet Pathol 2004; 41:527-32. [PMID: 15347829 DOI: 10.1354/vp.41-5-527] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neurologic disease occurs sporadically in horses infected with the equine infectious anemia virus (EIAV). This report describes a case of clinically severe neurologic disease in a pony experimentally infected with EIAV. This pony did not have fever or anemia, which are the characteristic clinical signs of disease. The histopathologic changes were characterized as lymphohistiocytic periventricular leukoencephalitis. Polymerase chain reaction and in situ hybridization data showed that the brain lesions were directly associated with viral replication and that high-level viral replication occurred selectively within the lesion and not in other tissues. These findings suggest that EIAV-associated neurologic disease is the direct result of viral replication.
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Baccam P, Thompson RJ, Li Y, Sparks WO, Belshan M, Dorman KS, Wannemuehler Y, Oaks JL, Cornette JL, Carpenter S. Subpopulations of equine infectious anemia virus Rev coexist in vivo and differ in phenotype. J Virol 2003; 77:12122-31. [PMID: 14581549 PMCID: PMC254257 DOI: 10.1128/jvi.77.22.12122-12131.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lentiviruses exist in vivo as a population of related, nonidentical genotypes, commonly referred to as quasispecies. The quasispecies structure is characteristic of complex adaptive systems and contributes to the high rate of evolution in lentiviruses that confounds efforts to develop effective vaccines and antiviral therapies. Here, we describe analyses of genetic data from longitudinal studies of genetic variation in a lentivirus regulatory protein, Rev, over the course of disease in ponies experimentally infected with equine infectious anemia virus. As observed with other lentivirus data, the Rev variants exhibited a quasispecies character. Phylogenetic and partition analyses suggested that the Rev quasispecies comprised two distinct subpopulations that coexisted during infection. One subpopulation appeared to accumulate changes in a linear, time-dependent manner, while the other evolved radially from a common variant. Over time, the two subpopulations cycled in predominance coincident with changes in the disease state, suggesting that the two groups differed in selective advantage. Transient expression assays indicated the two populations differed significantly in Rev nuclear export activity. Chimeric proviral clones containing Rev genotypes representative of each population differed in rate and overall level of virus replication in vitro. The coexistence of genetically distinct viral subpopulations that differ in phenotype provides great adaptability to environmental changes within the infected host. A quasispecies model with multiple subpopulations may provide additional insight into the nature of lentivirus reservoirs and the evolution of antigenic and drug-resistant variants.
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Affiliation(s)
- Prasith Baccam
- Department of Mathematics, Iowa State University, Ames, Iowa, USA
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50
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Fraser DG, Mealey RH, McGuire TC. Selecting peptides to optimize Th1 responses to an equine lentivirus using HLA-DR binding motifs and defined HIV-1 Th peptides. Immunogenetics 2003; 55:508-14. [PMID: 12942208 DOI: 10.1007/s00251-003-0600-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2003] [Revised: 07/28/2003] [Indexed: 11/30/2022]
Abstract
Three moderately to broadly recognized equine infectious anemia virus (EIAV) peptides that contained helper T-lymphocyte (Th) 1 epitopes were previously identified. Although lipopeptide immunization was only weakly immunostimulatory in a preliminary study, as measured by T-lymphocyte proliferation responses, it was of interest to define additional broadly recognized Th1 epitopes to include in future immunization trials. Using broadly cross-reactive and conserved Th epitopes known in the related human immunodeficiency virus-1 (HIV-1) and binding motifs defined in human leukocyte antigen DR molecules as guides, this work identified three new peptides containing Th1 epitopes recognized by 60-75% of EIAV infected horses. The observed similarity across species of major histocompatibility complex (MHC) class II binding motifs and the conservation of Th peptides between related viruses should allow easier targeting of Th epitope regions in less well characterized pathogens and/or in species whose MHC class II molecules are poorly defined.
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Affiliation(s)
- Darrilyn G Fraser
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA
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