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Weidinger AK, Bergmann M, König M, Zablotski Y, Hartmann K. Anti-rabies humoral immune response in cats after concurrent vs separate vaccination against rabies and feline leukaemia virus using canarypox-vectored vaccines. J Feline Med Surg 2024; 26:1098612X231218643. [PMID: 38358295 PMCID: PMC10911302 DOI: 10.1177/1098612x231218643] [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] [Indexed: 02/16/2024]
Abstract
OBJECTIVES Some expert groups recommend that cats should be vaccinated with non-adjuvanted feline leukaemia virus (FeLV) and rabies vector vaccines, which, in the European Union, are currently not licensed for concurrent use and have to be administered at least 14 days apart (different from the USA) and thus at separate visits, which is associated with more stress for cats and owners. The aim of this study was to assess the anti-rabies antibody response in cats after vaccination against rabies and FeLV at concurrent vs separate (4 weeks apart) visits using two canarypox-vectored vaccines (Purevax Rabies and Purevax FeLV; Boehringer Ingelheim) and to evaluate the occurrence of vaccine-associated adverse events (VAAEs). METHODS Healthy FeLV antigen-negative client-owned kittens (n = 106) were prospectively included in this randomised study. All kittens received primary vaccinations against rabies (week 0) and FeLV (weeks 4 and 8). After 1 year, the study group (n = 52) received booster vaccinations against rabies and FeLV concurrently at the same visit (weeks 50-52). The control group (n = 54) received booster vaccinations against rabies (weeks 50-52) and FeLV (weeks 54-56) separately. Anti-rabies virus antibodies (anti-RAV Ab) were determined by fluorescent antibody virus neutralisation assay at weeks 4, 50-52 and 54-56, and compared between both groups using a Mann-Whitney U-test. RESULTS Four weeks after the first rabies vaccination, 87/106 (82.1%) kittens had a titre ⩾0.5 IU/ml and 19/106 (17.9%) had a titre <0.5 IU/ml. Four weeks after the 1-year rabies booster, all cats had adequate anti-RAV Ab according to the World Organisation for Animal Health (⩾0.5 IU/ml), and the titres of the study group (median = 14.30 IU/ml) and the control group (median = 21.39 IU/ml) did not differ significantly (P = 0.141). VAAEs were observed in 7/106 (6.6%) cats. CONCLUSIONS AND RELEVANCE Concurrent administration of Purevax FeLV and Purevax Rabies vector vaccines at the 1-year booster does not interfere with the development of anti-RAV Ab or cause more adverse effects and thus represents a better option than separate vaccination visits for cats and owners.
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Affiliation(s)
- Anna-Karina Weidinger
- LMU Small Animal Clinic, Centre for Clinical Veterinary Medicine, LMU Munich, Munich, Germany
| | - Michèle Bergmann
- LMU Small Animal Clinic, Centre for Clinical Veterinary Medicine, LMU Munich, Munich, Germany
| | - Matthias König
- Institute of Virology, Faculty of Veterinary Medicine, Justus Liebig University, Giessen, Hessen, Germany
| | - Yury Zablotski
- LMU Small Animal Clinic, Centre for Clinical Veterinary Medicine, LMU Munich, Munich, Germany
| | - Katrin Hartmann
- LMU Small Animal Clinic, Centre for Clinical Veterinary Medicine, LMU Munich, Munich, Germany
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2
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Moll GM, Swenson CL, Yuzbasiyan-Gurkan V. BET Inhibitor JQ1 Attenuates Feline Leukemia Virus DNA, Provirus, and Antigen Production in Domestic Cat Cell Lines. Viruses 2023; 15:1853. [PMID: 37766260 PMCID: PMC10535802 DOI: 10.3390/v15091853] [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: 08/04/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Feline leukemia virus (FeLV) is a cosmopolitan gammaretrovirus that causes lifelong infections and fatal diseases, including leukemias, lymphomas, immunodeficiencies, and anemias, in domestic and wild felids. There is currently no definitive treatment for FeLV, and while existing vaccines reduce the prevalence of progressive infections, they neither provide sterilizing immunity nor prevent regressive infections that result in viral reservoirs with the potential for reactivation, transmission, and the development of associated clinical diseases. Previous studies of murine leukemia virus (MuLV) established that host cell epigenetic reader bromodomain and extra-terminal domain (BET) proteins facilitate MuLV replication by promoting proviral integration. Here, we provide evidence that this facilitatory effect of BET proteins extends to FeLV. Treatment with the archetypal BET protein bromodomain inhibitor (+)-JQ1 and FeLV challenge of two phenotypically disparate feline cell lines, 81C fibroblasts and 3201 lymphoma cells, significantly reduced FeLV proviral load, total FeLV DNA load, and p27 capsid protein expression at nonlethal concentrations. Moreover, significant decreases in FeLV proviral integration were documented in 81C and 3201 cells. These findings elucidate the importance of BET proteins for efficient FeLV replication, including proviral integration, and provide a potential target for treating FeLV infections.
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Affiliation(s)
- Garrick M. Moll
- Comparative Medicine & Integrative Biology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA;
| | - Cheryl L. Swenson
- Comparative Medicine & Integrative Biology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA;
- Department of Pathobiology & Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
| | - Vilma Yuzbasiyan-Gurkan
- Comparative Medicine & Integrative Biology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA;
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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Ortiz R, Barajas A, Pons-Grífols A, Trinité B, Tarrés-Freixas F, Rovirosa C, Urrea V, Barreiro A, Gonzalez-Tendero A, Cardona M, Ferrer L, Clotet B, Carrillo J, Aguilar-Gurrieri C, Blanco J. Exploring FeLV-Gag-Based VLPs as a New Vaccine Platform-Analysis of Production and Immunogenicity. Int J Mol Sci 2023; 24:ijms24109025. [PMID: 37240371 DOI: 10.3390/ijms24109025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/11/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Feline leukemia virus (FeLV) is one of the most prevalent infectious diseases in domestic cats. Although different commercial vaccines are available, none of them provides full protection. Thus, efforts to design a more efficient vaccine are needed. Our group has successfully engineered HIV-1 Gag-based VLPs that induce a potent and functional immune response against the HIV-1 transmembrane protein gp41. Here, we propose to use this concept to generate FeLV-Gag-based VLPs as a novel vaccine strategy against this retrovirus. By analogy to our HIV-1 platform, a fragment of the FeLV transmembrane p15E protein was exposed on FeLV-Gag-based VLPs. After optimization of Gag sequences, the immunogenicity of the selected candidates was evaluated in C57BL/6 and BALB/c mice, showing strong cellular and humoral responses to Gag but failing to generate anti-p15E antibodies. Altogether, this study not only tests the versatility of the enveloped VLP-based vaccine platform but also sheds light on FeLV vaccine research.
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Affiliation(s)
- Raquel Ortiz
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- Doctorate School, Microbiology Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Ana Barajas
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- Doctorate School, Medicine Department, University of Vic-Central University of Catalonia (UVic-UCC), 08500 Vic, Spain
| | - Anna Pons-Grífols
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- Doctorate School, Microbiology Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
| | - Benjamin Trinité
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
| | | | - Carla Rovirosa
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
| | - Victor Urrea
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
| | | | | | | | | | - Bonaventura Clotet
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- Doctorate School, Medicine Department, University of Vic-Central University of Catalonia (UVic-UCC), 08500 Vic, Spain
- Infectious Diseases Department, Germans Trias I Pujol Hospital, 08916 Badalona, Spain
| | - Jorge Carrillo
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- CIBERINFEC, ISCIII, 28029 Madrid, Spain
| | | | - Julià Blanco
- AIDS Research Institute, IrsiCaixa, Campus Can Ruti, 08916 Badalona, Spain
- Doctorate School, Microbiology Department, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
- Doctorate School, Medicine Department, University of Vic-Central University of Catalonia (UVic-UCC), 08500 Vic, Spain
- CIBERINFEC, ISCIII, 28029 Madrid, Spain
- Germans Trias I Pujol Research Institute (IGTP), Campus Can Ruti, 08916 Badalona, Spain
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4
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Westman ME, Giselbrecht J, Norris JM, Malik R, Green J, Burton-Bradley E, Cheang A, Meili T, Meli ML, Hartmann K, Hofmann-Lehmann R. Field Performance of a Rapid Test to Detect Progressive, Regressive, and Abortive Feline Leukemia Virus Infections in Domestic Cats in Australia and Germany. Viruses 2023; 15:v15020491. [PMID: 36851705 PMCID: PMC9967048 DOI: 10.3390/v15020491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/12/2023] Open
Abstract
Different feline leukemia virus (FeLV) infection outcomes are possible in cats following natural exposure, such as progressive infections (persistent viremia), regressive infections (transient or no viremia followed by proviral persistence) and abortive infections (presence of only antibodies). Laboratory-based testing is currently required for categorization of infection outcomes in cats. The aim of this study was to evaluate the field performance of a novel, rapid, combination point-of-care (PoC) test kit commercially available in Europe (v-RetroFel®Ag/Ab; 2020-2021 version) to determine different FeLV infection outcomes by concurrent detection of FeLV antigen (p27) and antibodies against FeLV transmembrane envelope protein (p15E). A secondary aim was to evaluate the performance of the same test kit (v-RetroFel®FIV) to determine positive/negative feline immunodeficiency virus (FIV) infection status by the detection of antibodies to FIV capsid protein (p24) and transmembrane glycoprotein (gp40). Two cohorts of domestic cats were recruited and tested with v-RetroFel® using plasma or serum, including cats in Australia (n = 200) and cats in Germany (n = 170). Results from p27 antigen PoC testing, proviral DNA PCR, and neutralizing antibody testing or testing for antibodies against non-glycosylated surface unit envelope protein (p45) were used to assign cats to groups according to different FeLV infection outcomes. Testing with a laboratory-based FeLV p15E antibody ELISA was also performed for comparison. In the first cohort, v-RetroFel®Ag/Ab correctly identified 89% (109/122) FeLV-unexposed cats and 91% (21/23) progressive infections, but no regressive (0/23) or abortive (0/32) infections. In the second cohort, v-RetroFel®Ag/Ab correctly identified 94% (148/158) FeLV-unexposed cats and 100% (4/4) progressive infections, but no regressive (0/2) and only 17% (1/6) abortive infections. There was test agreement between v-RetroFel®Ab and the p15E laboratory ELISA in 58.9% of samples. As a secondary outcome of this study, the sensitivity and specificity of v-RetroFel®FIV testing in cohort 1 were 94.7% (18/19) and 98.3% (178/181), and in cohort 2, 30.0% (3/10) and 100.0% (160/160), respectively. Prior history of FIV vaccination did not produce any false-positive FIV results. In conclusion, v-RetroFel®Ag/Ab (2020-2021 version) was unable to accurately determine different FeLV infection outcomes in the field. Improvements of the test prior to application to field samples are required.
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Affiliation(s)
- Mark E. Westman
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
- Correspondence:
| | - Juliana Giselbrecht
- Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine LMU Munich, Veterinaerstrasse 13, 80539 Munich, Germany
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, The University of Zurich, CH-8057 Zurich, Switzerland
| | - Jacqueline M. Norris
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
- The Sydney Institute for Infectious Diseases, The University of Sydney, Sydney, NSW 2006, Australia
| | - Richard Malik
- Centre for Veterinary Education, The University of Sydney, Sydney, NSW 2006, Australia
- School of Veterinary and Animal Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Jennifer Green
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Elle Burton-Bradley
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Ashley Cheang
- Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW 2006, Australia
| | - Theres Meili
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, The University of Zurich, CH-8057 Zurich, Switzerland
| | - Marina L. Meli
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, The University of Zurich, CH-8057 Zurich, Switzerland
| | - Katrin Hartmann
- Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine LMU Munich, Veterinaerstrasse 13, 80539 Munich, Germany
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, The University of Zurich, CH-8057 Zurich, Switzerland
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Abstract
Vaccines protect cats from serious diseases by inducing antibodies and cellular immune responses. Primary vaccinations and boosters are given according to vaccination guidelines provided by industry and veterinary organizations, based on minimal duration of immunity (DOI). For certain diseases, particularly feline panleukopenia, antibody titres correlate with protection. For feline calicivirus and feline herpesvirus, a similar correlation is absent, or less clear. In this review, the European Advisory Board on Cat Diseases (ABCD) presents current knowledge and expert opinion on the use of antibody testing in different situations. Antibody testing can be performed either in diagnostic laboratories, or in veterinary practice using point of care (POC) tests, and can be applied for several purposes, such as to provide evidence that a successful immune response was induced following vaccination. In adult cats, antibody test results can inform the appropriate re-vaccination interval. In shelters, antibody testing can support the control of FPV outbreaks by identifying potentially unprotected cats. Antibody testing has also been proposed to support decisions on optimal vaccination schedules for the individual kitten. However, such testing is still expensive and it is considered impractical to monitor the decline of maternally derived antibodies.
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Molina VM, Orjuela M. Frecuencia de la leucemia felina (vilef): refugio municipal Rionegro, Colombia 2020. REVISTA DE LA FACULTAD DE MEDICINA VETERINARIA Y DE ZOOTECNIA 2022. [DOI: 10.15446/rfmvz.v69n1.101522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
La leucemia viral felina (ViLeF) es una enfermedad retroviral letal, de una elevada prevalencia en Colombia, que afecta a felinos de diferentes edades y sexos. El objetivo de esta investigación fue determinar la frecuencia por serodiagnóstico de ViLeF en felinos del centro integral de bienestar animal Ceiba, ubicado en Rionegro, Antioquia (Colombia), en 2020. Para ello, se realizó un estudio descriptivo longitudinal de serofrecuencia de ViLeF desde enero hasta diciembre de 2020. Fueron muestreados 92 gatos, a los cuales se les efectuó una prueba p27 por inmunoensayo comercial Elisa (Idexx©, Snap Combo Plus®, Maine, EE. UU.). La frecuencia de felinos positivos fue 30/92 (32,60%) y el mes de mayo fue el de mayor frecuencia (9,78%). Los machos positivos fueron 17/92 (18,47%) y las hembras 13/92 (14,13%). La edad promedio de seropositividad fue 2,14 años. La frecuencia de ViLeF en 2020 para Ceiba, Rionegro (Colombia) es de 32,60%, un valor elevado con respecto a descripciones en otros albergues para felinos. ViLeF es una enfermedad que está siendo reportada con mayor frecuencia en Colombia, debido a que las medidas de prevención no se están adoptando rutinariamente.
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7
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Adeno-Associated Vector-Delivered CRISPR/ SaCas9 System Reduces Feline Leukemia Virus Production In Vitro. Viruses 2021; 13:v13081636. [PMID: 34452500 PMCID: PMC8402633 DOI: 10.3390/v13081636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/12/2021] [Accepted: 08/14/2021] [Indexed: 12/16/2022] Open
Abstract
Feline leukemia virus (FeLV) is a retrovirus of cats worldwide. High viral loads are associated with progressive infection and the death of the host, due to FeLV-associated disease. In contrast, low viral loads, an effective immune response, and a better clinical outcome can be observed in cats with regressive infection. We hypothesize that by lowering viral loads in progressively infected cats, using CRISPR/SaCas9-assisted gene therapy, the cat’s immune system may be permitted to direct the infection towards a regressive outcome. In a step towards this goal, the present study evaluates different adeno-associated vectors (AAVs) for their competence in delivering a gene editing system into feline cells, followed by investigations of the CRISPR/SaCas9 targeting efficiency for different sites within the FeLV provirus. Nine natural AAV serotypes, two AAV hybrid strains, and Anc80L65, an in silico predicted AAV ancestor, were tested for their potential to infect different feline cell lines and feline primary cells. AAV-DJ revealed superior infection efficiency and was thus employed in subsequent transduction experiments. The introduction of double-strand breaks, using the CRISPR/SaCas9 system targeting 12 selected FeLV provirus sites, was confirmed by T7 endonuclease 1 (T7E1), as well as Tracking of Indels by Decomposition (TIDE) analysis. The highest percentage (up to 80%) of nonhomologous end-joining (NHEJ) was found in the highly conserved gag and pol regions. Subsequent transduction experiments, using AAV-DJ, confirmed indel formation and showed a significant reduction in FeLV p27 antigen for some targets. The targeting of the FeLV provirus was efficient when using the CRISPR/SaCas9 approach in vitro. Whether the observed extent of provirus targeting will be sufficient to provide progressively FeLV-infected cats with the means to overcome the infection needs to be further investigated in vivo.
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8
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Parr YA, Beall MJ, Levy JK, McDonald M, Hamman NT, Willett BJ, Hosie MJ. Measuring the Humoral Immune Response in Cats Exposed to Feline Leukaemia Virus. Viruses 2021; 13:v13030428. [PMID: 33800090 PMCID: PMC7998633 DOI: 10.3390/v13030428] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/23/2021] [Accepted: 03/05/2021] [Indexed: 01/18/2023] Open
Abstract
Retroviruses belong to an important and diverse family of RNA viruses capable of causing neoplastic disease in their hosts. Feline leukaemia virus (FeLV) is a gammaretrovirus that infects domestic and wild cats, causing immunodeficiency, cytopenia and neoplasia in progressively infected cats. The outcome of FeLV infection is influenced by the host immune response; progressively infected cats demonstrate weaker immune responses compared to regressively infected cats. In this study, humoral immune responses were examined in 180 samples collected from 123 domestic cats that had been naturally exposed to FeLV, using a novel ELISA to measure antibodies recognizing the FeLV surface unit (SU) glycoprotein in plasma samples. A correlation was demonstrated between the strength of the humoral immune response to the SU protein and the outcome of exposure. Cats with regressive infection demonstrated higher antibody responses to the SU protein compared to cats belonging to other outcome groups, and samples from cats with regressive infection contained virus neutralising antibodies. These results demonstrate that an ELISA that assesses the humoral response to FeLV SU complements the use of viral diagnostic tests to define the outcome of exposure to FeLV. Together these tests could allow the rapid identification of regressively infected cats that are unlikely to develop FeLV-related disease.
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Affiliation(s)
- Yasmin A. Parr
- MRC—University of Glasgow Centre for Virus Research, Glasgow, Scotland G61 1QH, UK; (B.J.W.); (M.J.H.)
- Correspondence: ; Tel.: +44-0-141-330-3444
| | | | - Julie K. Levy
- Maddie’s Shelter Medicine Program, University of Florida, Gainesville, FL 32608, USA;
| | - Michael McDonald
- Veterinary Diagnostic Services, University of Glasgow, Glasgow, Scotland G61 1QH, UK;
| | | | - Brian J. Willett
- MRC—University of Glasgow Centre for Virus Research, Glasgow, Scotland G61 1QH, UK; (B.J.W.); (M.J.H.)
| | - Margaret J. Hosie
- MRC—University of Glasgow Centre for Virus Research, Glasgow, Scotland G61 1QH, UK; (B.J.W.); (M.J.H.)
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Beall MJ, Buch J, Clark G, Estrada M, Rakitin A, Hamman NT, Frenden MK, Jefferson EP, Amirian ES, Levy JK. Feline Leukemia Virus p27 Antigen Concentration and Proviral DNA Load Are Associated with Survival in Naturally Infected Cats. Viruses 2021; 13:302. [PMID: 33671961 PMCID: PMC7919025 DOI: 10.3390/v13020302] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 12/18/2022] Open
Abstract
Longitudinal studies of cats naturally infected with feline leukemia virus (FeLV) are important for understanding disease outcomes. Levels of p27 antigen and copy numbers of proviral DNA have been associated with FeLV-infection courses. The purpose of this prospective study was to establish cutoff values for p27 antigen concentration and proviral DNA load that distinguished high positive from low positive groups of cats and to evaluate an association with survival. At enrollment, 254 cats were tested by point-of-care and microtiter plate enzyme-linked immunosorbent assays (ELISAs) for p27 antigen and real-time polymerase chain reaction (PCR) for proviral DNA. The 127 positive cats were retested monthly for six months and monitored for survival over the four-year study. A receiver operating characteristic-based analysis of samples with concordant or discordant qualitative results for p27 antigen and proviral DNA was used to establish cutoff values, and when applied to test results at enrollment for classifying cats as high positive or low positive, a significant difference in survival was observed. High positive cats had a median survival of 1.37 years (95% CI 0.83-2.02) from time of enrollment, while most low positive cats were still alive (93.1% survival). Quantitative results for p27 antigen concentration and proviral DNA load were highly correlated with survival times in FeLV-infected cats.
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Affiliation(s)
- Melissa J. Beall
- IDEXX Laboratories, Inc., Westbrook, ME 04092, USA; (J.B.); (G.C.); (M.E.); (A.R.)
| | - Jesse Buch
- IDEXX Laboratories, Inc., Westbrook, ME 04092, USA; (J.B.); (G.C.); (M.E.); (A.R.)
| | - Genevieve Clark
- IDEXX Laboratories, Inc., Westbrook, ME 04092, USA; (J.B.); (G.C.); (M.E.); (A.R.)
| | - Marko Estrada
- IDEXX Laboratories, Inc., Westbrook, ME 04092, USA; (J.B.); (G.C.); (M.E.); (A.R.)
| | - Andrei Rakitin
- IDEXX Laboratories, Inc., Westbrook, ME 04092, USA; (J.B.); (G.C.); (M.E.); (A.R.)
| | - Natascha T. Hamman
- Austin Pets Alive!, Austin, TX 78703, USA; (N.T.H.); (M.K.F.); (E.P.J.); (E.S.A.)
| | - Monica K. Frenden
- Austin Pets Alive!, Austin, TX 78703, USA; (N.T.H.); (M.K.F.); (E.P.J.); (E.S.A.)
| | - Ellen P. Jefferson
- Austin Pets Alive!, Austin, TX 78703, USA; (N.T.H.); (M.K.F.); (E.P.J.); (E.S.A.)
| | - E. Susan Amirian
- Austin Pets Alive!, Austin, TX 78703, USA; (N.T.H.); (M.K.F.); (E.P.J.); (E.S.A.)
| | - Julie K. Levy
- Maddie’s Shelter Medicine Program, University of Florida, Gainesville, FL 32608, USA;
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Anti-SU Antibody Responses in Client-Owned Cats Following Vaccination against Feline Leukaemia Virus with Two Inactivated Whole-Virus Vaccines (Fel-O-Vax ® Lv-K and Fel-O-Vax ® 5). Viruses 2021; 13:v13020240. [PMID: 33546485 PMCID: PMC7913631 DOI: 10.3390/v13020240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/29/2021] [Accepted: 02/02/2021] [Indexed: 12/16/2022] Open
Abstract
A field study undertaken in Australia compared the antibody responses induced in client-owned cats that had been vaccinated using two inactivated whole feline leukaemia virus (FeLV) vaccines, the monovalent vaccine Fel-O-Vax® Lv-K and the polyvalent vaccine Fel-O-Vax® 5. Serum samples from 428 FeLV-uninfected cats (118 FeLV-vaccinated and 310 FeLV-unvaccinated) were tested for anti-FeLV neutralising antibodies (NAb) using a live virus neutralisation assay to identify 378 FeLV-unexposed (NAb-negative) and 50 FeLV-exposed (NAb-positive; abortive infections) cats, following by anti-surface unit (SU) FeLV-A and FeLV-B antibody ELISA testing. An additional 42 FeLV-infected cats (28 presumptively regressively infected, 14 presumptively progressively infected) were also tested for anti-SU antibodies. NAb-positive cats displayed significantly higher anti-SU antibody ELISA responses compared to NAb-negative cats (p < 0.001). FeLV-unexposed cats (NAb-negative) that had been vaccinated less than 18 months after a previous FeLV vaccination using the monovalent vaccine (Fel-O-Vax® Lv-K) displayed higher anti-SU antibody ELISA responses than a comparable group vaccinated with the polyvalent vaccine (Fel-O-Vax® 5) (p < 0.001 for both anti-FeLV-A and FeLV-B SU antibody responses). This difference in anti-SU antibody responses between cats vaccinated with the monovalent or polyvalent vaccine, however, was not observed in cats that had been naturally exposed to FeLV (NAb-positive) (p = 0.33). It was postulated that vaccination with Fel-O-Vax® 5 primed the humoral response prior to FeLV exposure, such that antibody production increased when the animal was challenged, while vaccination with Fel-O-Vax® Lv-K induced an immediate preparatory antibody response that did not quantitatively increase after FeLV exposure. These results raise questions about the comparable vaccine efficacy of the different FeLV vaccine formulations and correlates of protection.
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11
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Hofmann-Lehmann R, Hartmann K. Feline leukaemia virus infection: A practical approach to diagnosis. J Feline Med Surg 2021; 22:831-846. [PMID: 32845225 DOI: 10.1177/1098612x20941785] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PRACTICAL RELEVANCE Feline leukaemia virus (FeLV) is a retrovirus of domestic cats worldwide. Cats lacking strong FeLV-specific immunity and undergoing progressive infection commonly develop fatal FeLV-associated disease. Many aspects of FeLV infection pathogenesis have been elucidated, some during more recent years using molecular techniques. It is recommended that the FeLV status of every cat is known, since FeLV infection can influence the prognosis and clinical management of every sick cat. Moreover, knowledge of a cat's FeLV status is of epidemiological importance to prevent further spread of the infection. CLINICAL CHALLENGES Diagnosing FeLV infection remains challenging due to different outcomes of infection, which can vary over time depending on the balance between the virus and the host's immune system. Furthermore, testing for FeLV infection has become more refined over the years and now includes diagnostic assays for different viral and immunological parameters. Knowledge of FeLV infection pathogenesis, as well as the particulars of FeLV detection methods, is an important prerequisite for correct interpretation of any test results and accurate determination of a cat's FeLV status. AIMS The current review presents recent knowledge on FeLV pathogenesis, key features to be determined in FeLV infection, and frequently used FeLV detection methods, and their characteristics and interpretation. An algorithm for the diagnosis of FeLV infection in a single cat, developed by the European Advisory Board on Cat Diseases, is included, and FeLV testing in specific situations is addressed. As well as increasing awareness of this deadly infection in domestic cats, the aim is to contribute diagnostic expertise to allow veterinarians in practice to improve their recognition, and further reduce the prevalence, of FeLV infection.
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Affiliation(s)
- Regina Hofmann-Lehmann
- Prof, Dr med vet, FVH Professor of Laboratory Medicine, Director of Department of Clinical Diagnostics and Services, Head of Clinical Laboratory and Centre for Clinical Studies, Vetsuisse Faculty, University of Zurich, Switzerland
| | - Katrin Hartmann
- Prof, Dr med vet, Dr habil, Dip ECVIM-CA (Internal Medicine) Professor of Internal Medicine, Head of Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine, LMU Munich, Germany
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12
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Hartmann K, Hofmann-Lehmann R. What's New in Feline Leukemia Virus Infection. Vet Clin North Am Small Anim Pract 2020; 50:1013-1036. [PMID: 32680664 DOI: 10.1016/j.cvsm.2020.05.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Feline leukemia virus (FeLV) is a retrovirus with global impact on the health of domestic cats that causes tumors (mainly lymphoma), bone marrow disorders, and immunosuppression. The importance of FeLV is underestimated due to complacency associated with previous decline in prevalence. However, with this comes lowered vigilance, which, along with potential for regressively infected cats to reactivate viremia and shed the virus or develop clinical signs, can pose a risk to feline health. This article summarizes knowledge on FeLV pathogenesis, courses of infection, and factors affecting prevalance, infection outcome, and development of FeLV-associated diseases, with special focus on regressive FeLV infection.
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Affiliation(s)
- Katrin Hartmann
- Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine LMU Munich, Veterinaerstrasse 13, Munich 80539, Germany.
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Department for Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, Zurich 8057, Switzerland
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13
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Little S, Levy J, Hartmann K, Hofmann-Lehmann R, Hosie M, Olah G, Denis KS. 2020 AAFP Feline Retrovirus Testing and Management Guidelines. J Feline Med Surg 2020; 22:5-30. [DOI: 10.1177/1098612x19895940] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Clinical importance: Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infections are found in cats worldwide. Both infections are associated with a variety of clinical signs and can impact quality of life and longevity. Scope: This document is an update of the 2008 American Association of Feline Practitioners’ feline retrovirus management guidelines and represents current knowledge on pathogenesis, diagnosis, prevention and treatment of retrovirus infections in cats. Testing and interpretation: Although vaccines are available for FeLV in many countries and for FIV in some countries, identification of infected cats remains an important factor for preventing new infections. The retrovirus status of every cat at risk of infection should be known. Cats should be tested as soon as possible after they are acquired, following exposure to an infected cat or a cat of unknown infection status, prior to vaccination against FeLV or FIV, and whenever clinical illness occurs. It might not be possible to determine a cat’s infection status based on testing at a single point in time; repeat testing using different methods could be required. Although FeLV and FIV infections can be associated with clinical disease, some infected cats, especially those infected with FIV, can live for many years with good quality of life. Management of infected cats: There is a paucity of data evaluating treatments for infected cats, especially antiretroviral and immunomodulatory drugs. Management of infected cats is focused on effective preventive healthcare strategies, and prompt identification and treatment of illness, as well as limiting the spread of infection.
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Affiliation(s)
- Susan Little
- Bytown Cat Hospital, Ottawa, ON, Canada
- Charing Cross Cat Clinic, Brantford, ON, Canada
| | - Julie Levy
- Maddie’s Shelter Medicine Program, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
- Charing Cross Cat Clinic, Brantford, ON, Canada
| | - Katrin Hartmann
- Clinic of Small Animal Medicine, Centre for Clinical Veterinary Medicine, LMU Munich, Munich, Germany
- Charing Cross Cat Clinic, Brantford, ON, Canada
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Department of Clinical Diagnostics and Services, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
- Charing Cross Cat Clinic, Brantford, ON, Canada
| | - Margaret Hosie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
- Charing Cross Cat Clinic, Brantford, ON, Canada
| | - Glenn Olah
- Albuquerque Cat Clinic, Albuquerque, NM, USA
- Charing Cross Cat Clinic, Brantford, ON, Canada
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Evaluation of a quantitative enzyme-linked immunosorbent assay for feline leukemia virus p27 antigen and comparison to proviral DNA loads by real-time polymerase chain reaction. Comp Immunol Microbiol Infect Dis 2019; 67:101348. [PMID: 31527012 DOI: 10.1016/j.cimid.2019.101348] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/14/2019] [Accepted: 08/30/2019] [Indexed: 11/23/2022]
Abstract
Feline leukemia virus (FeLV) is an oncogenic retrovirus of cats. While higher viral RNA and proviral DNA loads have been correlated with progressive infections and disease, a similar correlation has been suggested for p27 antigen concentrations. This analytical study compared the results of a quantitative ELISA for p27 antigen with quantitative real-time PCR results for FeLV proviral DNA in patient samples. A significant positive correlation between copies of proviral DNA and the concentration of p27 antigen was identified (r = 0.761, P < 0.0001). Samples with high proviral DNA loads, at least 1 × 106 copies/mL of whole blood, typically had p27 antigen concentrations greater than 30 ng/mL in plasma. Samples with proviral DNA loads below this level all had concentrations of p27 antigen in plasma that were less than 10 ng/mL. Given this correlation, it is hypothesized that the concentration of p27 antigen at a given point in time may help to indicate the likelihood of a progressive or regressive infection similar to what has been demonstrated for proviral DNA loads.
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Olagoke O, Quigley BL, Eiden MV, Timms P. Antibody response against koala retrovirus (KoRV) in koalas harboring KoRV-A in the presence or absence of KoRV-B. Sci Rep 2019; 9:12416. [PMID: 31455828 PMCID: PMC6711960 DOI: 10.1038/s41598-019-48880-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 08/13/2019] [Indexed: 01/13/2023] Open
Abstract
Koala retrovirus (KoRV) is in the process of endogenization into the koala (Phascolarctos cinereus) genome and is currently spreading through the Australian koala population. Understanding how the koala's immune system responds to KoRV infection is critical for developing an efficacious vaccine to protect koalas. To this end, we analyzed the antibody response of 235 wild koalas, sampled longitudinally over a four-year period, that harbored KoRV-A, and with or without KoRV-B. We found that the majority of the sampled koalas were able to make anti-KoRV antibodies, and that there was a linear increase in anti-KoRV IgG levels in koalas up to approximately seven years of age and then a gradual decrease thereafter. Koalas infected with both KoRV-A and KoRV-B were found to have slightly higher anti-KoRV IgG titers than koalas with KoRV-A alone and there was an inverse relationship between anti-KoRV IgG levels and circulating KoRV viral load. Finally, we identified distinct epitopes on the KoRV envelope protein that were recognized by antibodies. Together, these findings provide insight into the koala's immune response to KoRV and may be useful in the development of a therapeutic KoRV vaccine.
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Affiliation(s)
- O Olagoke
- Genecology Research Center, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, 4556, Queensland, Australia
| | - B L Quigley
- Genecology Research Center, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, 4556, Queensland, Australia
| | - M V Eiden
- Section on Directed Gene Transfer, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA
| | - P Timms
- Genecology Research Center, University of the Sunshine Coast, 90 Sippy Downs Drive, Sippy Downs, 4556, Queensland, Australia.
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Nesina S, Katrin Helfer-Hungerbuehler A, Riond B, Boretti FS, Willi B, Meli ML, Grest P, Hofmann-Lehmann R. Retroviral DNA--the silent winner: blood transfusion containing latent feline leukemia provirus causes infection and disease in naïve recipient cats. Retrovirology 2015; 12:105. [PMID: 26689419 PMCID: PMC4687292 DOI: 10.1186/s12977-015-0231-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/09/2015] [Indexed: 11/23/2022] Open
Abstract
Background
The feline leukemia virus (FeLV) is a gamma-retrovirus of domestic cats that was discovered half a century ago. Cats that are infected with FeLV may develop a progressive infection resulting in persistent viremia, immunodeficiency, tumors, anemia and death. A significant number of cats mount a protective immune response that suppresses viremia; these cats develop a regressive infection characterized by the absence of viral replication and the presence of low levels of proviral DNA. The biological importance of these latter provirus carriers is largely unknown. Results Here, we demonstrate that ten cats that received a transfusion of blood from aviremic provirus carriers developed active FeLV infections, some with a progressive outcome and the development of fatal FeLV-associated disease. The infection outcome, disease spectrum and evolution into FeLV-C in one cat mirrored those of natural infection. Two cats developed persistent antigenemia; six cats were transiently antigenemic. Reactivation of infection occurred in some cats. One recipient developed non-regenerative anemia associated with FeLV-C, and four others developed a T-cell lymphoma, one with secondary lymphoblastic leukemia. Five of the ten recipient cats received provirus-positive aviremic blood, whereas the other five received provirus- and viral RNA-positive but aviremic blood. Notably, the cats that received blood containing only proviral DNA exhibited a later onset but graver outcome of FeLV infection than the cats that were transfused with blood containing proviral DNA and viral RNA. Leukocyte counts and cytokine analyses indicated that the immune system of the latter cats reacted quicker and more efficiently. Conclusions Our results underline the biological and epidemiological relevance of FeLV provirus carriers and the risk of inadvertent FeLV transmission via blood transfusion and demonstrate the replication capacity of proviral DNA if uncontrolled by the immune system. Our results have implications not only for veterinary medicine, such as the requirement for testing blood donors and blood products for FeLV provirus by sensitive polymerase chain reaction, but are also of general interest by revealing the importance of latent retroviral DNA in infected hosts. When aiming to eliminate a retroviral infection from a population, provirus carriers must be considered. Electronic supplementary material The online version of this article (doi:10.1186/s12977-015-0231-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stefanie Nesina
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. .,Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - A Katrin Helfer-Hungerbuehler
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. .,Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Barbara Riond
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Felicitas S Boretti
- Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Barbara Willi
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. .,Clinic for Small Animal Internal Medicine, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Marina L Meli
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. .,Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Paula Grest
- Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland. .,Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
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Comparative Efficacy of Feline Leukemia Virus (FeLV) Inactivated Whole-Virus Vaccine and Canarypox Virus-Vectored Vaccine during Virulent FeLV Challenge and Immunosuppression. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:798-805. [PMID: 25972402 PMCID: PMC4478526 DOI: 10.1128/cvi.00034-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 04/22/2015] [Indexed: 11/24/2022]
Abstract
Four vaccines for feline leukemia virus (FeLV) are available in the United States. This study's purpose was to compare the efficacy of Nobivac feline 2-FeLV (an inactivated, adjuvanted whole-virus vaccine) and PureVax recombinant FeLV (a live, canarypox virus-vectored vaccine) following FeLV challenge. Cats were vaccinated at 9 and 12 weeks with Nobivac feline 2-FeLV (group A, n = 11) or PureVax recombinant FeLV (group B, n = 10). Group C (n = 11) comprised unvaccinated controls. At 3 months postvaccination, cats were immunosuppressed and challenged with FeLV-A/61E. The outcomes measured were persistent antigenemia at 12 weeks postchallenge (PC) and proviral DNA and viral RNA at 3 to 9 weeks PC. Persistent antigenemia was observed in 0 of 11 cats in group A, 5 of 10 cats in group B, and 10 of 11 cats in group C. Group A was significantly protected compared to those in groups B (P < 0.013) and C (P < 0.0001). No difference was found between groups B and C (P > 0.063). The preventable fraction was 100% for group A and 45% for group B. At 9 weeks PC, proviral DNA and viral RNA were detected 1 of 11 cats in group A, 6 of 10 cats in group B, and 9 of 11 cats in group C. Nucleic acid loads were significantly lower in group A than in group C (P < 0.01). Group A had significantly lower proviral DNA loads than group B at weeks 6 to 9 (P < 0.02). The viral RNA loads were significantly lower in group A than in group B at weeks 7 to 9 (P < 0.01). The results demonstrate that Nobivac feline 2-FeLV-vaccinated cats were fully protected against persistent antigenemia and had significantly smaller amounts of proviral DNA and plasma viral RNA loads than PureVax recombinant FeLV-vaccinated cats and unvaccinated controls.
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18
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No benefit of therapeutic vaccination in clinically healthy cats persistently infected with feline leukemia virus. Vaccine 2015; 33:1578-85. [PMID: 25698488 DOI: 10.1016/j.vaccine.2015.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/04/2015] [Indexed: 11/22/2022]
Abstract
Therapeutic vaccinations have a potential application in infections where no curative treatment is available. In contrast to HIV, efficacious vaccines for a cat retrovirus, feline leukemia virus (FeLV), are commercially available. However, the infection is still prevalent, and no effective treatment of the infection is known. By vaccinating persistently FeLV-infected cats and presenting FeLV antigens to the immune system of the host, e.g., in the form of recombinant and/or adjuvanted antigens, we intended to shift the balance toward an advantage of the host so that persistent infection could be overcome by the infected cat. Two commercially available FeLV vaccines efficacious in protecting naïve cats from FeLV infection were tested in six experimentally and persistently FeLV-infected cats: first, a canarypox-vectored vaccine, and second, an adjuvanted, recombinant envelope vaccine was repeatedly administered with the aim to stimulate the immune system. No beneficial effects on p27 antigen and plasma viral RNA loads, anti-FeLV antibodies, or life expectancy of the cats were detected. The cats were unable to overcome or decrease viremia. Some cats developed antibodies to FeLV antigens although not protective. Thus, we cannot recommend vaccinating persistently FeLV-infected cats as a means of improving their FeLV status, quality of life or life expectancy. We suggest testing of all cats for FeLV infection prior to FeLV vaccination.
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Helfer-Hungerbuehler AK, Widmer S, Kessler Y, Riond B, Boretti FS, Grest P, Lutz H, Hofmann-Lehmann R. Long-term follow up of feline leukemia virus infection and characterization of viral RNA loads using molecular methods in tissues of cats with different infection outcomes. Virus Res 2015; 197:137-50. [DOI: 10.1016/j.virusres.2014.12.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 12/18/2014] [Accepted: 12/19/2014] [Indexed: 10/24/2022]
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A targeted mutation within the feline leukemia virus (FeLV) envelope protein immunosuppressive domain to improve a canarypox virus-vectored FeLV vaccine. J Virol 2013; 88:992-1001. [PMID: 24198407 DOI: 10.1128/jvi.02234-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We previously delineated a highly conserved immunosuppressive (IS) domain within murine and primate retroviral envelope proteins that is critical for virus propagation in vivo. The envelope-mediated immunosuppression was assessed by the ability of the proteins, when expressed by allogeneic tumor cells normally rejected by engrafted mice, to allow these cells to escape, at least transiently, immune rejection. Using this approach, we identified key residues whose mutation (i) specifically abolishes immunosuppressive activity without affecting the "mechanical" function of the envelope protein and (ii) significantly enhances humoral and cellular immune responses elicited against the virus. The objective of this work was to study the immunosuppressive activity of the envelope protein (p15E) of feline leukemia virus (FeLV) and evaluate the effect of its abolition on the efficacy of a vaccine against FeLV. Here we demonstrate that the FeLV envelope protein is immunosuppressive in vivo and that this immunosuppressive activity can be "switched off" by targeted mutation of a specific amino acid. As a result of the introduction of the mutated envelope sequence into a previously well characterized canarypox virus-vectored vaccine (ALVAC-FeLV), the frequency of vaccine-induced FeLV-specific gamma interferon (IFN-γ)-producing cells was increased, whereas conversely, the frequency of vaccine-induced FeLV-specific interleukin-10 (IL-10)-producing cells was reduced. This shift in the IFN-γ/IL-10 response was associated with a higher efficacy of ALVAC-FeLV against FeLV infection. This study demonstrates that FeLV p15E is immunosuppressive in vivo, that the immunosuppressive domain of p15E can modulate the FeLV-specific immune response, and that the efficacy of FeLV vaccines can be enhanced by inhibiting the immunosuppressive activity of the IS domain through an appropriate mutation.
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21
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Holmes JC, Holmer SG, Ross P, Buntzman AS, Frelinger JA, Hess PR. Polymorphisms and tissue expression of the feline leukocyte antigen class I loci FLAI-E, FLAI-H, and FLAI-K. Immunogenetics 2013; 65:675-89. [PMID: 23812210 PMCID: PMC3777221 DOI: 10.1007/s00251-013-0711-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/18/2013] [Indexed: 01/14/2023]
Abstract
Cytotoxic CD8+ T-cell immunosurveillance for intracellular pathogens, such as viruses, is controlled by classical major histocompatibility complex (MHC) class Ia molecules, and ideally, these antiviral T-cell populations are defined by the specific peptide and restricting MHC allele. Surprisingly, despite the utility of the cat in modeling human viral immunity, little is known about the feline leukocyte antigen class I complex (FLAI). Only a few coding sequences with uncertain locus origin and expression patterns have been reported. Of 19 class I genes, three loci--FLAI-E, FLAI-H, and FLAI-K--are predicted to encode classical molecules, and our objective was to evaluate their status by analyzing polymorphisms and tissue expression. Using locus-specific, PCR-based genotyping, we amplified 33 FLAI-E, FLAI-H, and FLAI-K alleles from 12 cats of various breeds, identifying, for the first time, alleles across three distinct loci in a feline species. Alleles shared the expected polymorphic and invariant sites in the α1/α2 domains, and full-length cDNA clones possessed all characteristic class Ia exons. Alleles could be assigned to a specific locus with reasonable confidence, although there was evidence of potentially confounding interlocus recombination between FLAI-E and FLAI-K. Only FLAI-E, FLAI-H, and FLAI-K origin alleles were amplified from cDNAs of multiple tissue types. We also defined hypervariable regions across these genes, which permitted the assignment of names to both novel and established alleles. As predicted, FLAI-E, FLAI-H, and FLAI-K fulfill the major criteria of class Ia genes. These data represent a necessary prerequisite for studying epitope-specific antiviral CD8+ T-cell responses in cats.
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Affiliation(s)
- Jennifer C. Holmes
- Immunology Program, and Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, United States of America
| | - Savannah G. Holmer
- Immunology Program, and Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, United States of America
| | - Peter Ross
- Immunology Program, and Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, United States of America
| | - Adam S. Buntzman
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
| | - Jeffrey A. Frelinger
- Department of Immunobiology, University of Arizona, Tucson, Arizona, United States of America
| | - Paul R. Hess
- Immunology Program, and Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, United States of America
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22
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Feline leukaemia virus: Half a century since its discovery. Vet J 2013; 195:16-23. [DOI: 10.1016/j.tvjl.2012.07.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/27/2012] [Accepted: 07/04/2012] [Indexed: 11/30/2022]
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23
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Abstract
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia), and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less commonly diagnosed than in the previous 20 years; prevalence has been decreasing in most countries. However, FeLV importance may be underestimated as it has been shown that regressively infected cats (that are negative in routinely used FeLV tests) also can develop clinical signs. FIV can cause an acquired immunodeficiency syndrome that increases the risk of opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. This article provides a review of clinical syndromes in progressively and regressively FeLV-infected cats as well as in FIV-infected cats.
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Affiliation(s)
- Katrin Hartmann
- Medizinische Kleintierklinik, LMU University of Munich, Germany, Veterinaerstrasse 13, 80539 Munich, Germany.
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24
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Englert T, Lutz H, Sauter-Louis C, Hartmann K. Survey of the feline leukemia virus infection status of cats in Southern Germany. J Feline Med Surg 2012; 14:392-8. [DOI: 10.1177/1098612x12440531] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most studies that investigate the prevalence of infections with feline leukemia virus (FeLV) are based on the detection of p27 antigen in blood, but they do not detect proviral DNA to identify the prevalence of regressive FeLV infections. The aim of the present study was to assess the prevalence and status of FeLV infection in cats in Southern Germany. P27 antigen enzyme-linked immunosorbent assay (ELISA), anti-p45 antibody ELISA, DNA polymerase chain reaction (PCR) of blood and RNA PCR of saliva were performed. Nine out of 495 cats were progressively (persistently) infected (1.8%) and six were regressively (latently) infected (1.2%). Cats with regressive infections are defined as cats that have been able to overcome antigenemia but provirus can be detected by PCR. Twenty-two unvaccinated cats likely had abortive infections (regressor cats), testing FeLV antigen- and provirus-negative but anti-p45 antibody-positive. Most of the FeLV-vaccinated cats did not have anti-FeLV antibodies. Both progressive, as well as regressive infections seem to be rare in Germany today.
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Affiliation(s)
| | - Hans Lutz
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland
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25
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Hartmann K. Clinical aspects of feline immunodeficiency and feline leukemia virus infection. Vet Immunol Immunopathol 2011; 143:190-201. [PMID: 21807418 PMCID: PMC7132395 DOI: 10.1016/j.vetimm.2011.06.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with a global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FIV can cause an acquired immunodeficiency syndrome that increases the risk of developing opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less important as a deadly infectious agent as in the last 20 years prevalence has been decreasing in most countries.
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Affiliation(s)
- Katrin Hartmann
- Clinic of Small Animal Medicine, LMU University of Munich, Veterinaerstrasse 13, 80539 Munich, Germany.
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26
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Geret CP, Cattori V, Meli ML, Riond B, Martínez F, López G, Vargas A, Simón MA, López-Bao JV, Hofmann-Lehmann R, Lutz H. Feline leukemia virus outbreak in the critically endangered Iberian lynx (Lynx pardinus): high-throughput sequencing of envelope variable region A and experimental transmission. Arch Virol 2011; 156:839-54. [PMID: 21302124 DOI: 10.1007/s00705-011-0925-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 01/18/2011] [Indexed: 12/18/2022]
Abstract
The Iberian lynx is the most endangered felid species. During winter/spring 2006/7, a feline leukemia virus (FeLV) outbreak of unexpected virulence killed about 2/3 of the infected Iberian lynxes. All FeLV-positive animals were co-infected with feline hemoplasmas. To further characterize the Iberian lynx FeLV strain and evaluate its potential virulence, the FeLV envelope gene variable region A (VRA) mutant spectrum was analyzed using the Roche 454 sequencing technology, and an in vivo transmission study of lynx blood to specified-pathogen-free cats was performed. VRA mutations indicated weak apolipoprotein B mRNA editing enzyme and catalytic polypeptide-like cytidine deaminase (APOBEC) restriction of FeLV replication, and variants characteristic of aggressive FeLV strains, such as FeLV-C or FeLV-A/61C, were not detected. Cats exposed to FeLV/Candidatus Mycoplasma haemominutum-positive lynx blood did not show a particularly severe outcome of infection. The results underscore the special susceptibility of Iberian lynxes to infectious diseases.
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Affiliation(s)
- C P Geret
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Switzerland
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27
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Helfer-Hungerbuehler AK, Cattori V, Boretti FS, Ossent P, Grest P, Reinacher M, Henrich M, Bauer E, Bauer-Pham K, Niederer E, Holznagel E, Lutz H, Hofmann-Lehmann R. Dominance of highly divergent feline leukemia virus A progeny variants in a cat with recurrent viremia and fatal lymphoma. Retrovirology 2010; 7:14. [PMID: 20167134 PMCID: PMC2837606 DOI: 10.1186/1742-4690-7-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 02/19/2010] [Indexed: 12/30/2022] Open
Abstract
Background In a cat that had ostensibly recovered from feline leukemia virus (FeLV) infection, we observed the reappearance of the virus and the development of fatal lymphoma 8.5 years after the initial experimental exposure to FeLV-A/Glasgow-1. The goals of the present study were to investigate this FeLV reoccurrence and molecularly characterize the progeny viruses. Results The FeLV reoccurrence was detected by the presence of FeLV antigen and RNA in the blood and saliva. The cat was feline immunodeficiency virus positive and showed CD4+ T-cell depletion, severe leukopenia, anemia and a multicentric monoclonal B-cell lymphoma. FeLV-A, but not -B or -C, was detectable. Sequencing of the envelope gene revealed three FeLV variants that were highly divergent from the virus that was originally inoculated (89-91% identity to FeLV-A/Glasgow-1). In the long terminal repeat 31 point mutations, some previously described in cats with lymphomas, were detected. The FeLV variant tissue provirus and viral RNA loads were significantly higher than the FeLV-A/Glasgow-1 loads. Moreover, the variant loads were significantly higher in lymphoma positive compared to lymphoma negative tissues. An increase in the variant provirus blood load was observed at the time of FeLV reoccurrence. Conclusions Our results demonstrate that ostensibly recovered FeLV provirus-positive cats may act as a source of infection following FeLV reactivation. The virus variants that had largely replaced the inoculation strain had unusually heavily mutated envelopes. The mutations may have led to increased viral fitness and/or changed the mutagenic characteristics of the virus.
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Torres AN, O'Halloran KP, Larson LJ, Schultz RD, Hoover EA. Feline leukemia virus immunity induced by whole inactivated virus vaccination. Vet Immunol Immunopathol 2009; 134:122-31. [PMID: 20004483 DOI: 10.1016/j.vetimm.2009.10.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A fraction of cats exposed to feline leukemia virus (FeLV) effectively contain virus and resist persistent antigenemia/viremia. Using real-time PCR (qPCR) to quantitate circulating viral DNA levels, previously we detected persistent FeLV DNA in blood cells of non-antigenemic cats considered to have resisted FeLV challenge. In addition, previously we used RNA qPCR to quantitate circulating viral RNA levels and determined that the vast majority of viral DNA is transcriptionally active, even in the absence of antigenemia. A single comparison of all USDA-licensed commercially available FeLV vaccines using these modern sensitive methods has not been reported. To determine whether FeLV vaccination would prevent nucleic acid persistence, we assayed circulating viral DNA, RNA, antigen, infectious virus, and virus neutralizing (VN) antibody in vaccinated and unvaccinated cats challenged with infectious FeLV. We identified challenged vaccinates with undetectable antigenemia and viremia concomitant with persistent FeLV DNA and/or RNA. Moreover, these studies demonstrated that two whole inactivated virus (WIV) adjuvanted FeLV vaccines (Fort Dodge Animal Health's Fel-O-Vax Lv-K) and Schering-Plough Animal Health's FEVAXYN FeLV) provided effective protection against FeLV challenge. In nearly every recipient of these vaccines, neither viral DNA, RNA, antigen, nor infectious virus could be detected in blood after FeLV challenge. Interestingly, this effective viral containment occurred despite a weak to undetectable VN antibody response. The above findings reinforce the precept of FeLV infection as a unique model of effective retroviral immunity elicited by WIV vaccination, and as such holds valuable insights into retroviral immunoprevention and therapy.
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Affiliation(s)
- Andrea N Torres
- Department of Microbiology, Immunology, and Pathology, 1619 Campus Delivery, Colorado State University, Ft. Collins, CO 80523-1619, USA
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29
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Major A, Cattori V, Boenzli E, Riond B, Ossent P, Meli ML, Hofmann-Lehmann R, Lutz H. Exposure of cats to low doses of FeLV: seroconversion as the sole parameter of infection. Vet Res 2009; 41:17. [PMID: 19861115 PMCID: PMC2789331 DOI: 10.1051/vetres/2009065] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Accepted: 10/26/2009] [Indexed: 12/02/2022] Open
Abstract
In felids, feline leukemia virus (FeLV) infection results in a variety of outcomes that range from abortive (virus readily eliminated and never detectable) to progressive infection (persistent viremia and viral shedding). Recently, a novel outcome was postulated for low FeLV infectious doses. Naïve cats exposed to faeces of persistently infected cats seroconverted, indicating infection, but remained negative for provirus and p27 antigen in blood. FeLV provirus was found in some tissues but not in the bone marrow, infection of which is usually considered a necessary stage for disease progression. To investigate the impact of low FeLV doses on young cats and to test the hypothesis that low dose exposure may lead to an unknown pathogenesis of infection without involvement of the bone marrow, 21 cats were infected oronasally with variable viral doses. Blood p27, proviral and viral loads were followed until week 20 post-infection. Tissue proviral loads were determined as well. The immune response was monitored by measuring FeLV whole virus and p45 antibodies; and feline oncornavirus-associated cell membrane antigen (FOCMA) assay. One cat showed regressive infection (transient antigenemia, persistent provirus-positivity, and seroconversion) with provirus only found in some organs at sacrifice. In 7 of the 20 remaining cats FOCMA assay positivity was the only sign of infection, while all other tests were negative. Overall, the results show that FeLV low dose exposure can result in seroconversion during a presumed abortive infection. Therefore, commonly used detection methods do not detect all FeLV-infected animals, possibly leading to an underestimation of the prevalence of infection.
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Affiliation(s)
- Andrea Major
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057, Zurich, Switzerland
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30
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Lutz H, Addie D, Belák S, Boucraut-Baralon C, Egberink H, Frymus T, Gruffydd-Jones T, Hartmann K, Hosie MJ, Lloret A, Marsilio F, Pennisi MG, Radford AD, Thiry E, Truyen U, Horzinek MC. Feline leukaemia. ABCD guidelines on prevention and management. J Feline Med Surg 2009; 11:565-74. [PMID: 19481036 PMCID: PMC7172531 DOI: 10.1016/j.jfms.2009.05.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OVERVIEW Feline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines. INFECTION Transmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30-40% will develop persistent viraemia, 30-40% show transient viraemia and 20-30% seroconvert. Young kittens are especially susceptible to FeLV infection. DISEASE SIGNS The most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2-3 years. DIAGNOSIS In low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested. DISEASE MANAGEMENT Supportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host. VACCINATION RECOMMENDATIONS All cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8-9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3-4 years of age, a booster every 2-3 years suffices, in view of the significantly lower susceptibility of older cats.
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Affiliation(s)
- Hans Lutz
- European Advisory Board on Cat Diseases (ABCD).
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31
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Levy J, Crawford C, Hartmann K, Hofmann-Lehmann R, Little S, Sundahl E, Thayer V. 2008 American Association of Feline Practitioners' feline retrovirus management guidelines. J Feline Med Surg 2008; 10:300-16. [DOI: 10.1016/j.jfms.2008.03.002] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2008] [Indexed: 11/16/2022]
Abstract
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are among the most common infectious diseases of cats. Although vaccines are available for both viruses, identification and segregation of infected cats form the cornerstone for preventing new infections. Guidelines in this report have been developed for diagnosis, prevention, treatment, and management of FeLV and FIV infections. All cats should be tested for FeLV and FIV infections at appropriate intervals based on individual risk assessments. This includes testing at the time of acquisition, following exposure to an infected cat or a cat of unknown infection status, prior to vaccination against FeLV or FIV, prior to entering group housing, and when cats become sick. No test is 100% accurate at all times under all conditions; results should be interpreted along with the patient's health and risk factors. Retroviral tests can diagnose only infection, not clinical disease, and cats infected with FeLV or FIV may live for many years. A decision for euthanasia should never be based solely on whether or not the cat is infected. Vaccination against FeLV is highly recommended in kittens. In adult cats, antiretroviral vaccines are considered non-core and should be administered only if a risk assessment indicates they are appropriate. Few large controlled studies have been performed using antiviral or immunomodulating drugs for the treatment of naturally infected cats. More research is needed to identify best practices to improve long-term outcomes following retroviral infections in cats.
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Affiliation(s)
- Julie Levy
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, United States
| | - Cynda Crawford
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, United States
| | - Katrin Hartmann
- Clinic of Small Animal Medicine, Ludwig Maximilian University Munich, Veterinaerstrasse 13, 80539 Munich, Germany
| | | | - Susan Little
- Winn Feline Foundation, 1805 Atlantic Avenue, PO Box 1005, Manasquan, NJ 08736-0805, United States
| | - Eliza Sundahl
- KC Cat Clinic, 7107 Main Street, Kansas City, MO 64114, United States
| | - Vicki Thayer
- Purrfect Practice PC, PO Box 550, Lebanon, OR 97355, United States
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32
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Tandon R, Cattori V, Pepin AC, Riond B, Meli ML, McDonald M, Doherr MG, Lutz H, Hofmann-Lehmann R. Association between endogenous feline leukemia virus loads and exogenous feline leukemia virus infection in domestic cats. Virus Res 2008; 135:136-43. [DOI: 10.1016/j.virusres.2008.02.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 02/28/2008] [Accepted: 02/29/2008] [Indexed: 11/25/2022]
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34
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Hofmann-Lehmann R, Cattori V, Tandon R, Boretti FS, Meli ML, Riond B, Lutz H. How molecular methods change our views of FeLV infection and vaccination. Vet Immunol Immunopathol 2008; 123:119-23. [DOI: 10.1016/j.vetimm.2008.01.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Cattori V, Pepin AC, Tandon R, Riond B, Meli ML, Willi B, Lutz H, Hofmann-Lehmann R. Real-time PCR investigation of feline leukemia virus proviral and viral RNA loads in leukocyte subsets. Vet Immunol Immunopathol 2008; 123:124-8. [DOI: 10.1016/j.vetimm.2008.01.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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36
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Torres AN, O'Halloran KP, Larson LJ, Schultz RD, Hoover EA. Development and application of a quantitative real-time PCR assay to detect feline leukemia virus RNA. Vet Immunol Immunopathol 2008; 123:81-9. [PMID: 18321595 DOI: 10.1016/j.vetimm.2008.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
We previously defined four categories of feline leukemia virus (FeLV) infection, designated as abortive, regressive, latent, and progressive. To determine if detectable viral DNA is transcriptionally active in the absence of antigenemia, we developed and validated a real-time viral RNA qPCR assay. This assay proved to be highly sensitive, specific, reproducible, and allowed reliable quantitation. We then applied this methodology, together with real-time DNA qPCR and p27 capsid antigen capture ELISA, to examine cats challenged with FeLV. We found that circulating viral RNA and DNA levels were highly correlated and the assays were almost in perfect agreement. This indicates that the vast majority of viral DNA is transcriptionally active, even in the absence of antigenemia. The real-time qPCR assays are more sensitive than the most commonly used FeLV diagnostic assay, the p27 capsid antigen capture ELISA. Application of qPCR assays may add greater depth in understanding of FeLV-host relationships.
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Affiliation(s)
- Andrea N Torres
- Department of Microbiology, Immunology, and Pathology, 1619 Campus Delivery, Colorado State University, Ft. Collins, CO 80523-1619, USA
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37
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High prevalence of Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) in Slovenia. ACTA VET-BEOGRAD 2008. [DOI: 10.2298/avb0803191t] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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38
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Poulet H, Minke J, Pardo MC, Juillard V, Nordgren B, Audonnet JC. Development and registration of recombinant veterinary vaccines. Vaccine 2007; 25:5606-12. [PMID: 17227690 DOI: 10.1016/j.vaccine.2006.11.066] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2006] [Revised: 11/14/2006] [Accepted: 11/30/2006] [Indexed: 11/28/2022]
Abstract
The canarypox vaccine vector (ALVAC) technology has been used to develop and license several vaccines for companion animals and horses in the European Union and USA. ALVAC is a ubiquitous vector with high biosafety since it is non-replicative in mammalians, is genetically and physically stable, and able to induce both humoral and cell-mediated immune responses against the expressed transgene product. Specific rules apply for the development and registration of recombinant vector vaccines. The biology of the vector as well as the recombinant virus must be thoroughly documented to allow the risk assessment of its use in the target species. In particular, its safety for the host and the environment must be extensively demonstrated before field trials can be authorized.
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Affiliation(s)
- Hervé Poulet
- Merial SAS, 254, rue Marcel Mérieux, 69007 Lyon, France.
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39
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Pepin AC, Tandon R, Cattori V, Niederer E, Riond B, Willi B, Lutz H, Hofmann-Lehmann R. Cellular segregation of feline leukemia provirus and viral RNA in leukocyte subsets of long-term experimentally infected cats. Virus Res 2007; 127:9-16. [PMID: 17434224 DOI: 10.1016/j.virusres.2007.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 03/02/2007] [Accepted: 03/13/2007] [Indexed: 11/24/2022]
Abstract
Cats exposed to feline leukemia virus (FeLV) may develop different outcomes of the infection. However, during acute infection blood proviral and viral RNA loads of cats with progressive and regressive infection are not significantly different. Thus, not the overall loads but rather those of specific leukocyte subsets may influence the infection outcome. By combining fluorescence activated cell sorting (FACS) with sensitive real-time TaqMan PCR and reverse transcriptase (RT) PCR, we established in the present study the methods to determine FeLV proviral and viral RNA loads in specific leukocyte subsets. In addition, they were applied to analyze long-term persistently FeLV-infected (p27-positive) and FeLV exposed but nonantigenemic (p27-negative), nonviremic cats. In the latter animals, CD4(+) and B lymphocytes exhibited the highest proviral loads, whereas in p27-positive cats, all leukocyte subsets showed similar high loads. In p27-positive cats, monocytes and granulocytes bore the highest viral RNA loads, whereas only one p27-negative cat was positive for viral RNA in T lymphocytes. To our knowledge, this is the first study to investigate FeLV proviral and viral RNA loads in leukocyte subsets of FeLV exposed cats. The herein described methods are important prerequisites to gain a deeper insight into the pathogenesis of FeLV infection.
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Affiliation(s)
- Andrea C Pepin
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Switzerland
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40
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Hofmann-Lehmann R, Cattori V, Tandon R, Boretti FS, Meli ML, Riond B, Pepin AC, Willi B, Ossent P, Lutz H. Vaccination against the feline leukaemia virus: outcome and response categories and long-term follow-up. Vaccine 2006; 25:5531-9. [PMID: 17240486 DOI: 10.1016/j.vaccine.2006.12.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 12/04/2006] [Accepted: 12/13/2006] [Indexed: 10/01/2022]
Abstract
Feline leukaemia virus (FeLV) is a pathogen inducing fatal disease in cats worldwide. By applying sensitive molecular assays, efficacious commonly used FeLV vaccines that protect cats from antigenaemia were found not to prevent proviral integration and minimal viral replication after challenge. Nonetheless, vaccines protected cats from FeLV-associated disease and prolonged life expectancy. The spectrum of host response categories was refined by investigating plasma viral RNA loads. All cats initially fought similar virus loads, although subsequently loads were associated with infection outcomes. Persistence of plasma viral RNA was moderately associated with reactivation of FeLV infection. In conclusion, sensitive molecular assays are important tools for reviewing pathogenesis of FeLV infection.
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Affiliation(s)
- Regina Hofmann-Lehmann
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstr. 260, CH-8057 Zurich, Switzerland.
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41
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Diagnosis of feline leukaemia virus infection by semi-quantitative real-time polymerase chain reaction. J Feline Med Surg 2006; 9:8-13. [PMID: 16861024 DOI: 10.1016/j.jfms.2006.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2006] [Indexed: 10/24/2022]
Abstract
In this paper the design and use of a semi-quantitative real-time polymerase chain reaction assay (RT-PCR) for feline leukaemia virus (FeLV) provirus is described. Its performance is evaluated against established methods of FeLV diagnosis, including virus isolation and enzyme-linked immunoassay (ELISA) in a population of naturally infected cats. The RT-PCR assay is found to have both a high sensitivity (0.92) and specificity (0.99) when examined by expectation maximisation methods and is also able to detect a large number of cats with low FeLV proviral loads that were negative by other conventional test methods.
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42
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Cattori V, Tandon R, Pepin A, Lutz H, Hofmann-Lehmann R. Rapid detection of feline leukemia virus provirus integration into feline genomic DNA. Mol Cell Probes 2006; 20:172-81. [PMID: 16488115 DOI: 10.1016/j.mcp.2005.11.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 11/18/2005] [Indexed: 01/21/2023]
Abstract
Feline leukemia virus (FeLV) is a gamma retrovirus that induces fatal diseases in domestic cats. Efficacious FeLV vaccines prevent persistent viremia and development of FeLV-related disease after virus exposure, but not minimal viral replication and a provirus-positive state as recently demonstrated using sensitive real-time PCR assays. Proviral integration is an important parameter of latent infection and persistence of retroviruses in infected cells. So far, FeLV-specific real-time PCR assays could not distinguish between the integrated and episomal forms of the provirus. Thus, it was the aim of the present study to develop a rapid assay for the detection of FeLV proviral integration. The test combines conventional and quantitative real-time PCR that use virus-specific primers and primers specific for cat genomic small interspersed nuclear elements. It was applied to analyze the time course of proviral integration into the genome of a feline fibroblast cell line and detect provirus integration in peripheral white blood cells from vaccinated and unvaccinated, FeLV-exposed cats. The newly developed rapid test will essentially contribute to a better understanding of the mechanisms involved in the pathogenesis of FeLV infection and be especially useful in the development of antiretroviral vaccines and therapies aimed at the inhibition of proviral integration.
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Affiliation(s)
- Valentino Cattori
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland.
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43
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Tandon R, Cattori V, Gomes-Keller MA, Meli ML, Golder MC, Lutz H, Hofmann-Lehmann R. Quantitation of feline leukaemia virus viral and proviral loads by TaqMan real-time polymerase chain reaction. J Virol Methods 2005; 130:124-32. [PMID: 16054243 DOI: 10.1016/j.jviromet.2005.06.017] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 06/16/2005] [Accepted: 06/23/2005] [Indexed: 11/20/2022]
Abstract
Feline leukaemia virus (FeLV) infection in cats is not only of veterinary importance but also a well-acknowledged animal model for studying the pathogenesis of retroviral disease. After virus exposure, different courses and outcomes of FeLV infection may prevail; they have been associated with cellular and humoral immune responses and the FeLV proviral load in peripheral blood. We hypothesized that the plasma viral RNA load might be an additional relevant indicator for the infection outcome. To quantify these loads, a real-time reverse transcriptase (RT) polymerase chain reaction (PCR) assay was developed. The assay amplifies FeLV-A, -B, and -C as some naturally infected cats could not be identified with a FeLV-A-based assay previously. The assay was applied to determine plasma FeLV RNA loads in cats infected both naturally and experimentally with FeLV. In addition, an improved real-time PCR assay for quantitation of FeLV proviral loads is described. The assays developed were more sensitive than ELISA and virus isolation in the early phase of infection. In addition, PCR allows the identification of provirus carriers that have overcome antigenaemia. Thus, for most effective detection of FeLV exposure and characterization of the infection in a cat, PCR assays are recommended as diagnostic tools.
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Affiliation(s)
- Ravi Tandon
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
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44
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O'Donovan LH, McMonagle EL, Taylor S, Bain D, Pacitti AM, Golder MC, McDonald M, Hanlon L, Onions DE, Argyle DJ, Jarrett O, Nicolson L. A vector expressing feline mature IL-18 fused to IL-1beta antagonist protein signal sequence is an effective adjuvant to a DNA vaccine for feline leukaemia virus. Vaccine 2005; 23:3814-23. [PMID: 15893619 PMCID: PMC7115661 DOI: 10.1016/j.vaccine.2005.02.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Accepted: 02/08/2005] [Indexed: 01/08/2023]
Abstract
DNA vaccination using vectors expressing the gag/pol and env genes of feline leukaemia virus (FeLV) and plasmids encoding feline interleukin-12 (IL-12) and IL-18 completely protected cats from viraemia following challenge [Hanlon L, Argyle D, Bain D, Nicolson L, Dunham S, Golder MC, et al. Feline leukaemia virus DNA vaccine efficacy is enhanced by coadministration with interleukin-12 (IL-12) and IL-18 expression vectors. J Virol 2001;75:8424-33]. However, the relative contribution of each cytokine gene towards protection is unknown. This study aimed to resolve this issue. IL-12 and IL-18 constructs were modified to ensure effective expression, and bioactivity was demonstrated using specific assays. Kittens were immunised intramuscularly with FeLV DNA and various cytokine constructs. Together with control kittens, these were challenged oronasally with FeLV and monitored for 15 weeks. All six kittens given FeLV, IL-12 and IL-18 were protected from the establishment of persistent viraemia and four from latent infection. Of six kittens immunised with FeLV DNA and IL-18, all were protected from viraemia and five from latent infection. In contrast, three of five kittens given FeLV DNA and IL-12 became persistently viraemic. Therefore, the adjuvant effect on the FeLV DNA vaccine appears to reside in the expression of IL-18.
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Affiliation(s)
- Lucy H O'Donovan
- MacRobert Laboratories, Institute of Comparative Medicine, University of Glasgow, Bearsden, Glasgow G61 1QH, UK.
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Torres AN, Mathiason CK, Hoover EA. Re-examination of feline leukemia virus: host relationships using real-time PCR. Virology 2005; 332:272-83. [PMID: 15661159 DOI: 10.1016/j.virol.2004.10.050] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2004] [Revised: 07/13/2004] [Accepted: 10/05/2004] [Indexed: 11/17/2022]
Abstract
The mechanisms responsible for effective vs. ineffective viral containment are central to immunoprevention and therapies of retroviral infections. Feline leukemia virus (FeLV) infection is unique as a naturally occurring, diametric example of effective vs. ineffective retroviral containment by the host. We developed a sensitive quantitative real-time DNA PCR assay specific for exogenous FeLV to further explore the FeLV-host relationship. By assaying p27 capsid antigen in blood and FeLV DNA in blood and tissues of successfully vaccinated, unsuccessfully vaccinated, and unvaccinated pathogen-free cats, we defined four statistically separable classes of FeLV infection, provisionally designated as abortive, regressive, latent, and progressive. These host-virus relationships were established by 8 weeks post-challenge and could be maintained for years. Real-time PCR methods offer promise in gaining deeper insight into the mechanisms of FeLV infection and immunity.
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Affiliation(s)
- Andrea N Torres
- Department of Microbiology, Immunology, and Pathology, Colorado State University, 1619 Campus Delivery, Fort Collins, CO, 80523-1619, USA
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Poulet H, Brunet S, Boularand C, Guiot AL, Leroy V, Tartaglia J, Minke J, Audonnet JC, Desmettre P. Efficacy of a canarypox virus-vectored vaccine against feline leukaemia. Vet Rec 2003; 153:141-5. [PMID: 12934796 DOI: 10.1136/vr.153.5.141] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Canarypox virus recombinant vaccines have a unique efficacy and safety profile for the vaccinated host because the canarypox virus is non-replicative in mammalian hosts. After the vaccination of a mammalian species, recombinant canarypox viruses express the inserted genes but cannot multiply in the host. They stimulate a strong immune response in the absence of any virus amplification in the host or any viral spread into the environment. A new canarypox-based recombinant vaccine is the canarypox-feline leukaemia virus (FeLV) vaccine (EURIFEL FeLV; Merial) that expresses the FeLV env and gag protective genes. This paper describes experiments which demonstrate that it is effective against any oronasal FeLV challenge. The protection was shown to be solid against an oronasal challenge one year after the initial vaccination, and was effective against a very severe 'in-contact' challenge. Furthermore, the canarypox virus-FeLV vaccine was effective without an adjuvant.
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Affiliation(s)
- H Poulet
- Merial, Laboratoire de Lyon Gerland, 254 rue Marcel Merieux, 69007 Lyon, France
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Graham EM, Jarrett O, Flynn JN. Development of antibodies to feline IFN-gamma as tools to elucidate the cellular immune responses to FeLV. J Immunol Methods 2003; 279:69-78. [PMID: 12969548 PMCID: PMC7125904 DOI: 10.1016/s0022-1759(03)00244-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An understanding of the nature of immune protection and the role of immune effector products such as interferon-gamma (IFN-gamma) in the control of infectious disease is fundamental to the rational design of effective vaccines and immunotherapeutic reagents. Murine monoclonal and sheep polyclonal antibodies (mAbs and pAbs) to feline IFN-gamma (fIFN-gamma) were generated firstly to facilitate further research into the role of cellular immune responses in the control of feline infectious disease, and secondly to enable evaluation of the efficacy of novel immunotherapeutic approaches. A hybridoma clone, D9, secreting IgG1 antibodies was selected for expansion and the mAbs affinity purified in vitro. Polyclonal antibodies were raised in a sheep against recombinant fIFN-gamma and affinity purified. The sensitivity of the D9 mAb and the sheep anti-fIFN-gamma pAb was determined using an indirect fIFN-gamma enzyme-linked immunosorbent assay (ELISA) and immunoblots. These antibodies were assessed for their ability to detect the production of fIFN-gamma by specific feline T cell populations ex vivo following coculture with mitogen or feline leukaemia virus (FeLV) antigens for 4 h in the presence of the protein secretion inhibitor brefeldin A (BFA). Production of fIFN-gamma was evaluated using flow cytometry to simultaneously detect PE-labelled surface molecules and fluorescein isothiocyanate (FITC)-labelled intracellular fIFN-gamma. Using this approach, our initial studies revealed an upregulation in virus-specific fIFN-gamma-secreting CD4(+)T cells in the lymph nodes of FeLV latently infected cats.
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Key Words
- ifn-γ
- antifeline antibodies
- feline cytokines
- feline leukaemia virus
- ap, alkaline phosphatase
- bfa, brefeldin a
- con a, concanavalin a
- elisa, enzyme-linked immunosorbent assay
- fcov, feline coronavirus
- felv, feline leukaemia virus
- fitc, fluorescein isothiocyanate
- fiv, feline immunodeficiency virus
- hiv, human immunodeficiency virus
- ifn-γ, interferon-γ
- pe, phycoerythrin
- rt, room temperature
- spf, specific pathogen free
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Affiliation(s)
- Elizabeth M Graham
- Department of Veterinary Pathology, University of Glasgow, Bearsden Road, G61 1QH Glasgow, UK
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