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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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Establishment of CRFK cells for vaccine production by inactivating endogenous retrovirus with TALEN technology. Sci Rep 2022; 12:6641. [PMID: 35477976 PMCID: PMC9046391 DOI: 10.1038/s41598-022-10497-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
Endogenous retroviruses (ERVs) are retroviral sequences present in the host genomes. Although most ERVs are inactivated, some are produced as replication-competent viruses from host cells. We previously reported that several live-attenuated vaccines for companion animals prepared using the Crandell-Rees feline kidney (CRFK) cell line were contaminated with a replication-competent feline ERV termed RD-114 virus. We also found that the infectious RD-114 virus can be generated by recombination between multiple RD-114 virus-related proviruses (RDRSs) in CRFK cells. In this study, we knocked out RDRS env genes using the genome-editing tool TAL Effector Nuclease (TALEN) to reduce the risk of contamination by infectious ERVs in vaccine products. As a result, we succeeded in establishing RDRS knockout CRFK cells (RDKO_CRFK cells) that do not produce infectious RD-114 virus. The growth kinetics of feline herpesvirus type 1, calicivirus, and panleukopenia virus in RDKO_CRFK cells differed from those in parental cells, but all of them showed high titers exceeding 107 TCID50/mL. Infectious RD-114 virus was undetectable in the viral stocks propagated in RDKO_CRFK cells. This study suggested that RDRS env gene-knockout CRFK cells will be useful as a cell line for the manufacture of live-attenuated vaccines or biological substances with no risk of contamination with infectious ERV.
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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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Westman M, Norris J, Malik R, Hofmann-Lehmann R, Harvey A, McLuckie A, Perkins M, Schofield D, Marcus A, McDonald M, Ward M, Hall E, Sheehy P, Hosie M. The Diagnosis of Feline Leukaemia Virus (FeLV) Infection in Owned and Group-Housed Rescue Cats in Australia. Viruses 2019; 11:v11060503. [PMID: 31159230 PMCID: PMC6630418 DOI: 10.3390/v11060503] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/29/2019] [Indexed: 12/11/2022] Open
Abstract
A field study was undertaken to (i) measure the prevalence of feline leukaemia virus (FeLV) exposure and FeLV infection in a cross-section of healthy Australian pet cats; and (ii) investigate the outcomes following natural FeLV exposure in two Australian rescue facilities. Group 1 (n = 440) consisted of healthy client-owned cats with outdoor access, predominantly from eastern Australia. Groups 2 (n = 38) and 3 (n = 51) consisted of a mixture of healthy and sick cats, group-housed in two separate rescue facilities in Sydney, Australia, tested following identification of index cases of FeLV infection in cats sourced from these facilities. Diagnostic testing for FeLV exposure/infection included p27 antigen testing using three different point-of-care FeLV kits and a laboratory-based ELISA, real-time polymerase chain reaction (qPCR) testing to detect FeLV proviral DNA in leukocytes, real-time reverse-transcription PCR (qRT-PCR) testing to detect FeLV RNA in plasma, and neutralising antibody (NAb) testing. Cats were classified as FeLV-uninfected (FeLV-unexposed and presumptively FeLV-abortive infections) or FeLV-infected (presumptively regressive and presumptively progressive infections). In Group 1, 370 FeLV-unexposed cats (370/440, 84%), 47 abortive infections (47/440, 11%), nine regressive infections (9/440, 2%), and two progressive infections (2/440, 0.5%) were identified, and 12 FeLV-uninfected cats (12/440, 3%) were unclassifiable as FeLV-unexposed or abortive infections due to insufficient samples available for NAb testing. In Groups 2 and 3, 31 FeLV-unexposed cats (31/89, 35%), eight abortive infections (8/89, 9%), 22 regressive infections (22/89; 25%), and 19 progressive infections (19/89; 21%) were discovered, and nine FeLV-uninfected cats (9/89; 10%) were unclassifiable due to insufficient samples available for NAb testing. One of the presumptively progressively-infected cats in Group 3 was likely a focal FeLV infection. Two other presumptively progressively-infected cats in Group 3 may have been classified as regressive infections with repeated testing, highlighting the difficulties associated with FeLV diagnosis when sampling cats at a single time point, even with results from a panel of FeLV tests. These results serve as a reminder to Australian veterinarians that the threat of FeLV to the general pet cat population remains high, thus vigilant FeLV testing, separate housing for FeLV-infected cats, and FeLV vaccination of at-risk cats is important, particularly in group-housed cats in shelters and rescue facilities, where outbreaks of FeLV infection can occur.
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Affiliation(s)
- Mark Westman
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, 2006 NSW, Australia.
| | - Jacqueline Norris
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, 2006 NSW, Australia.
| | - Richard Malik
- Centre for Veterinary Education, The University of Sydney, Camperdown, 2006 NSW, Australia.
| | - Regina Hofmann-Lehmann
- Clinical Laboratory and Centre for Clinical Studies, Vetsuisse Faculty, The University of Zurich, CH-8057 Zürich, Switzerland.
| | - Andrea Harvey
- Small Animal Specialist Hospital, 1 Richardson Place, North Ryde, Sydney, 2113 NSW, Australia.
| | - Alicia McLuckie
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, 2006 NSW, Australia.
| | | | | | - Alan Marcus
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, 2006 NSW, Australia.
| | - Mike McDonald
- Veterinary Diagnostic Services, The University of Glasgow, Glasgow, Scotland G61 1QH, UK.
| | - Michael Ward
- Sydney School of Veterinary Science, The University of Sydney, Camden, 2570 NSW, Australia.
| | - Evelyn Hall
- Sydney School of Veterinary Science, The University of Sydney, Camden, 2570 NSW, Australia.
| | - Paul Sheehy
- Sydney School of Veterinary Science, The University of Sydney, Camden, 2570 NSW, Australia.
| | - Margaret Hosie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, Scotland G61 1QH, UK.
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5
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Wilkes RP, Anis E, Dunbar D, Lee PYA, Tsai YL, Lee FC, Chang HFG, Wang HTT, Graham EM. Rapid and sensitive insulated isothermal PCR for point-of-need feline leukaemia virus detection. J Feline Med Surg 2017; 20:362-369. [PMID: 28589743 PMCID: PMC5871024 DOI: 10.1177/1098612x17712847] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objectives Feline leukaemia virus (FeLV), a gamma retrovirus, causes diseases of the
feline haematopoietic system that are invariably fatal. Rapid and accurate
testing at the point-of-need (PON) supports prevention of virus spread and
management of clinical disease. This study evaluated the performance of an
insulated isothermal PCR (iiPCR) that detects proviral DNA, and a reverse
transcription (RT)-iiPCR that detects both viral RNA and proviral DNA, for
FeLV detection at the PON. Methods Mycoplasma haemofelis, feline coronavirus, feline
herpesvirus, feline calicivirus and feline immunodeficiency virus were used
to test analytical specificity. In vitro transcribed RNA, artificial
plasmid, FeLV strain American Type Culture Collection VR-719 and a clinical
FeLV isolate were used in the analytical sensitivity assays. A retrospective
study including 116 clinical plasma and serum samples that had been tested
with virus isolation, real-time PCR and ELISA, and a prospective study
including 150 clinical plasma and serum samples were implemented to evaluate
the clinical performances of the iiPCR-based methods for FeLV detection. Results Ninety-five percent assay limit of detection was calculated to be 16 RNA and
five DNA copies for the RT-iiPCR, and six DNA copies for the iiPCR. Both
reactions had analytical sensitivity comparable to a reference real-time PCR
(qPCR) and did not detect five non-target feline pathogens. The clinical
performance of the RT-iiPCR and iiPCR had 98.82% agreement (kappa[κ] = 0.97)
and 100% agreement (κ = 1.0), respectively, with the qPCR (n = 85). The
agreement between an automatic nucleic extraction/RT-iiPCR system and virus
isolation to detect FeLV in plasma or serum was 95.69% (κ = 0.95) and 98.67%
(κ = 0.85) in a retrospective (n = 116) and a prospective (n = 150) study,
respectively. Conclusions and relevance These results suggested that both RT-iiPCR and iiPCR assays can serve as
reliable tools for PON FeLV detection.
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Affiliation(s)
- Rebecca P Wilkes
- 1 Clinical Virology Laboratory, University of Tennessee Veterinary Medical Center, Knoxville, TN, USA.,*Current address: Veterinary Diagnostic and Investigational Laboratory, College of Veterinary Medicine, University of Georgia, Tifton, GA, USA
| | - Eman Anis
- 1 Clinical Virology Laboratory, University of Tennessee Veterinary Medical Center, Knoxville, TN, USA.,2 Department of Virology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Beheira, Egypt.,*Current address: Veterinary Diagnostic and Investigational Laboratory, College of Veterinary Medicine, University of Georgia, Tifton, GA, USA
| | - Dawn Dunbar
- 3 Veterinary Diagnostic Services, School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | | | | | | | | | | | - Elizabeth M Graham
- 3 Veterinary Diagnostic Services, School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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6
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Hartmann K, Griessmayr P, Schulz B, Greene CE, Vidyashankar AN, Jarrett O, Egberink HF. Quality of different in-clinic test systems for feline immunodeficiency virus and feline leukaemia virus infection. J Feline Med Surg 2016; 9:439-45. [PMID: 17604205 DOI: 10.1016/j.jfms.2007.04.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2007] [Indexed: 10/23/2022]
Abstract
Many new diagnostic in-house tests for identification of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection have been licensed for use in veterinary practice, and the question of the relative merits of these kits has prompted comparative studies. This study was designed to define the strengths and weaknesses of seven FIV and eight FeLV tests that are commercially available. In this study, 536 serum samples from randomly selected cats were tested. Those samples reacting FIV-positive in at least one of the tests were confirmed by Western blot, and those reacting FeLV-positive were confirmed by virus isolation. In addition, a random selection of samples testing negative in all test systems was re-tested by Western blot (100 samples) and by virus isolation (81 samples). Specificity, sensitivity, positive and negative predictive values of each test and the quality of the results were compared.
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Affiliation(s)
- Katrin Hartmann
- Clinic for Small Animal Medicine, Ludwig Maximilian University Munich, Veterinaerstrasse 13, 80539 Munich, Germany.
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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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Hashimoto-Gotoh A, Yoshikawa R, Miyazawa T. Comparison between S+L- assay and LacZ marker rescue assay for detecting replication-competent gammaretroviruses. Biologicals 2015; 43:363-8. [PMID: 26164289 DOI: 10.1016/j.biologicals.2015.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/29/2015] [Accepted: 06/15/2015] [Indexed: 12/11/2022] Open
Abstract
To avoid contamination of adventitious gammaretroviruses in biological products such as vaccines, it is necessary to check the master seed cells for manufacturing. There are several assays to detect infectious gammaretroviruses. Among these, sarcoma-positive, leukemia-negative (S+L-) assay is a classical infectivity assay, which is often recommended in governmental guidelines. The S+L- cells used in S+L- assay generate unique focus upon the infection of replication-competent gammaretroviruses. Although S+L- assay is well recognized for the detection, their applicability is questionable in some cases. On the other hand, LacZ marker rescue (LMR) assay detects infectious gammaretroviruses by transducing LacZ marker gene to the target cells, which shows lacZ-positive foci if the infectious virus is present. In this study, we compared LMR and S+L- assays for detection of a variety of endogenous and exogenous gammaretroviruses. As results, LMR assay could detect all gammaretroviruses examined. On the other hand, S+L- assay using feline S+L- cells, termed QN10S, could not detect porcine endogenous retrovirus (PERV) subgroups A/B. Further, S+L- mink cells could not detect feline leukemia virus subgroups B in addition to PERV-A/B. These data indicate that LMR assay is better suited to detect wider range of gammaretroviruses.
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Affiliation(s)
- A Hashimoto-Gotoh
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - R Yoshikawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - T Miyazawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
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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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Yoshikawa R, Miyaho RN, Hashimoto A, Abe M, Yasuda J, Miyazawa T. Suppression of production of baboon endogenous virus by dominant negative mutants of cellular factors involved in multivesicular body sorting pathway. Virus Res 2014; 196:128-34. [PMID: 25463055 DOI: 10.1016/j.virusres.2014.11.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/14/2014] [Accepted: 11/14/2014] [Indexed: 12/31/2022]
Abstract
Baboon endogenous virus (BaEV) is an infectious endogenous gammaretrovirus isolated from a baboon placenta. BaEV-related sequences have been identified in both Old World monkeys and African apes, but not in humans or Asian apes. Recently, it was reported that BaEV-like particles were produced from Vero cells derived from African green monkeys by chemical induction, and thus BaEV-like particles may contaminate biological products manufactured using Vero cells. In this study, we constructed an infectious molecular clone of BaEV strain M7. We found two putative L-domain motifs, PPPY and PSAP, in the pp15 region of Gag. To examine the function of the L-domain motifs, we conducted virus budding assay using L-domain motif mutants. We revealed that the PPPY motif, but not the PSAP motif, plays a major role as the L-domain in BaEV budding. We also demonstrated that Vps4A/B are involved in BaEV budding. These data suggest that BaEV Gag recruits the cellular endosomal sorting complex required for transport (ESCRT) machinery through the interaction of the PPPY L-domain with cellular factors. These data will be useful for controlling contamination of BaEV-like particles in biological products in the future.
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Affiliation(s)
- Rokusuke Yoshikawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Rie Nakaoka Miyaho
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Akira Hashimoto
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Masumi Abe
- Fifth Biology Section for Microbiology, First Department of Forensic Science, National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwai, Chiba 277-0882, Japan
| | - Jiro Yasuda
- Department of Emerging Infectious Disease, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan
| | - Takayuki Miyazawa
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
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Detection of antibodies to the feline leukemia Virus (FeLV) transmembrane protein p15E: an alternative approach for serological FeLV detection based on antibodies to p15E. J Clin Microbiol 2014; 52:2046-52. [PMID: 24696026 DOI: 10.1128/jcm.02584-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this report was to investigate whether the diagnosis of feline leukemia virus (FeLV) infection by serology might be feasible and useful. Among the various viral proteins, the FeLV env-gene product (SU) and the envelope transmembrane protein p15E were considered promising candidates for the serological diagnosis of FeLV infection. Thus, we evaluated p15E and three other FeLV antigens, namely, a recombinant env-gene product, whole FeLV, and a short peptide from the FeLV transmembrane protein, for their potential to detect FeLV infection. To evaluate possible exposure of cats to FeLV, we tested serum and plasma samples from experimentally and naturally infected and vaccinated cats for the presence of antibodies to these antigens by enzyme-linked immunosorbent assays (ELISAs). The serological results were compared with the p27 and proviral real-time PCR results. We found that p15E displayed a diagnostic sensitivity of 95.7% and a specificity of 100% in experimentally infected cats. In naturally infected cats, p15E showed a diagnostic sensitivity of 77.1% and a specificity of 85.6%. Vaccinated cats displayed minimal antibody levels to p15E, suggesting that anti-p15E antibodies indicate infection rather than vaccination. The other antigens turned out to be too unspecific. The lower specificity in cats exposed to FeLV under field conditions may be explained by the fact that some cats become infected and seroconvert in the absence of detectable viral nucleic acids in plasma. We conclude that p15E serology may become a valuable tool for diagnosing FeLV infection; in some cases, it may replace PCR.
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12
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Antibody response to vaccines for rhinotracheitis, caliciviral disease, panleukopenia, feline leukemia, and rabies in tigers (Panthera tigris) and lions (Panthera leo). J Zoo Wildl Med 2012; 43:248-55. [PMID: 22779227 DOI: 10.1638/2010-0166.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This article presents the results of a study of captive tigers (Panthera tigris) and lions (Panthera leo) vaccinated with a recombinant vaccine against feline leukemia virus; an inactivated adjuvanted vaccine against rabies virus; and a multivalent modified live vaccine against feline herpesvirus, calicivirus, and panleukopenia virus. The aim of the study was to assess the immune response and safety of the vaccines and to compare the effects of the administration of single (1 ml) and double (2 ml) doses. The animals were separated into two groups and received either single or double doses of vaccines, followed by blood collection for serologic response for 400 days. No serious adverse event was observed, with the exception of abortion in one lioness, potentially caused by the incorrect use of the feline panleukopenia virus modified live vaccine. There was no significant difference between single and double doses for all vaccines. The recombinant vaccine against feline leukemia virus did not induce any serologic response. The vaccines against rabies and feline herpesvirus induced a significant immune response in the tigers and lions. The vaccine against calicivirus did not induce a significant increase in antibody titers in either tigers or lions. The vaccine against feline panleukopenia virus induced a significant immune response in tigers but not in lions. This report demonstrates the value of antibody titer determination after vaccination of nondomestic felids.
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13
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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. [PMID: 22403413 PMCID: PMC10822583 DOI: 10.1177/1098612x12440531] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
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)
- Theresa Englert
- Clinic of Small Animal Medicine, Ludwig Maximilian University Munich, Munich, Germany.
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14
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Patel JR, Heldens JGM, Bakonyi T, Rusvai M. Important mammalian veterinary viral immunodiseases and their control. Vaccine 2012; 30:1767-81. [PMID: 22261411 PMCID: PMC7130670 DOI: 10.1016/j.vaccine.2012.01.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 01/03/2012] [Accepted: 01/05/2012] [Indexed: 11/16/2022]
Abstract
This paper offers an overview of important veterinary viral diseases of mammals stemming from aberrant immune response. Diseases reviewed comprise those due to lentiviruses of equine infectious anaemia, visna/maedi and caprine arthritis encephalitis and feline immunodeficiency. Diseases caused by viruses of feline infectious peritonitis, feline leukaemia, canine distemper and aquatic counterparts, Aleutian disease and malignant catarrhal fever. We also consider prospects of immunoprophylaxis for the diseases and briefly other control measures. It should be realised that the outlook for effective vaccines for many of the diseases is remote. This paper describes the current status of vaccine research and the difficulties encountered during their development.
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Affiliation(s)
- J R Patel
- Jas Biologicals Ltd, 12 Pembroke Avenue, Denny Industrial Estate, Waterbeach, Cambridge CB25 9QR, UK.
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15
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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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16
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Miyazawa T, Yoshikawa R, Golder M, Okada M, Stewart H, Palmarini M. Isolation of an infectious endogenous retrovirus in a proportion of live attenuated vaccines for pets. J Virol 2010; 84:3690-4. [PMID: 20106919 PMCID: PMC2838105 DOI: 10.1128/jvi.02715-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 01/19/2010] [Indexed: 11/20/2022] Open
Abstract
The genomes of all animal species are colonized by endogenous retroviruses (ERVs). Although most ERVs have accumulated defects that render them incapable of replication, fully infectious ERVs have been identified in various mammals. In this study, we isolated a feline infectious ERV (RD-114) in a proportion of live attenuated vaccines for pets. Isolation of RD-114 was made in two independent laboratories using different detection strategies and using vaccines for both cats and dogs commercially available in Japan or the United Kingdom. This study shows that the methods currently employed to screen veterinary vaccines for retroviruses should be reevaluated.
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Affiliation(s)
- Takayuki Miyazawa
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
| | - Rokusuke Yoshikawa
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
| | - Matthew Golder
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
| | - Masaya Okada
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
| | - Hazel Stewart
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
| | - Massimo Palmarini
- Laboratory of Signal Transduction, Institute for Virus Research, Kyoto University, 53 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan, Institute of Comparative Medicine, University of Glasgow Faculty of Veterinary Medicine, 464 Bearsden Road, Glasgow G61 1QH, Scotland
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17
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Nakaya Y, Shojima T, Hoshino S, Miyazawa T. Focus assay on FeLIX-dependent feline leukemia virus. J Vet Med Sci 2009; 72:117-21. [PMID: 19915325 DOI: 10.1292/jvms.09-0194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
T-lymphotropic feline leukemia virus (FeLV-T) induces immunodeficiency in cats. FeLV-T is fusion-defective and requires a cofactor, termed FeLIX, for infection. FeLIX is a truncated envelope glycoprotein of an endogenous FeLV and mediates infection by binding a phosphate transporter Pit-1. In this study, we established a feline sarcoma-positive leukemia-negative cell line expressing FeLIX, named QN/FeLIX cells. Upon infection, FeLV-T induced prominent foci with syncytia in QN/FeLIX cells and could be titrated by the focus assay. In addition, we established a FeLIX-expressing feline fibroblast cell line, named AH/FeLIX cells. FeLV-T productively infected AH/FeLIX cells and induced severe CPE with syncytia. QN/FeLIX and AH/FeLIX cells will be useful for the study of FeLIX-dependent mutants in FeLV-infected cats.
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Affiliation(s)
- Yuki Nakaya
- Laboratory of Signal Transduction, Department of Cell Biology, Institute for Virus Research, Kyoto University, Kyoto, Japan
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18
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Abstract
DNA vaccines represent a new frontier in vaccine technology. One important application of this technology is in the veterinary arena. DNA vaccines have already gained a foothold in certain fields of veterinary medicine. However, several important questions must be addressed when developing DNA vaccines for animals, including whether or not the vaccine is efficacious and cost effective compared with currently available options. Another important question to consider is how to apply this developing technology in a wide range of different situations, from the domestic pet to individual fish in fisheries with several thousand animals, to wildlife programs for disease control. In some cases, DNA vaccines represent an interesting option for vaccination, while in others, currently available options are sufficient. This review will examine a number of diseases of veterinary importance and the progress being made in DNA vaccine technology relevant to these diseases, and we compare these with the conventional treatment options available.
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Affiliation(s)
- Laurel Redding
- University of Pennsylvania School of Veterinary Medicine, 3800 Spruce Street, University of Pennsylvania, Philadelphia, PA 19104, USA,
| | - David B Werner
- Department of Pathology and Laboratory Medicine, 422 Curie Boulevard – 505 SCL, University of Pennsylvania, Philadelphia, PA 19104, USA, Tel.: +1 215 349 8365, Fax: +1215 573 9436,
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19
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Hisasue M, Nagashima N, Nishigaki K, Fukuzawa I, Ura S, Katae H, Tsuchiya R, Yamada T, Hasegawa A, Tsujimoto H. Myelodysplastic syndromes and acute myeloid leukemia in cats infected with feline leukemia virus clone33 containing a unique long terminal repeat. Int J Cancer 2009; 124:1133-41. [PMID: 19035458 DOI: 10.1002/ijc.24050] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Feline leukemia virus (FeLV) clone33 was obtained from a domestic cat with acute myeloid leukemia (AML). The long terminal repeat (LTR) of this virus, like the LTRs present in FeLV from other cats with AML, differs from the LTRs of other known FeLV in that it has 3 tandem direct 47-bp repeats in the upstream region of the enhancer (URE). Here, we injected cats with FeLV clone33 and found 41% developed myelodysplastic syndromes (MDS) characterized by peripheral blood cytopenias and dysplastic changes in the bone marrow. Some of the cats with MDS eventually developed AML. The bone marrow of the majority of cats with FeLV clone33 induced MDS produced fewer erythroid and myeloid colonies upon being cultured with erythropoietin or granulocyte-macrophage colony-stimulating factor (GM-SCF) than bone marrow from normal control cats. Furthermore, the bone marrow of some of the cats expressed high-levels of the apoptosis-related genes TNF-alpha and survivin. Analysis of the proviral sequences obtained from 13 cats with naturally occurring MDS reveal they also bear the characteristic URE repeats seen in the LTR of FeLV clone33 and other proviruses from cats with AML. Deletions and mutations within the enhancer elements are frequently observed in naturally occurring MDS as well as AML. These results suggest that FeLV variants that bear URE repeats in their LTR strongly associate with the induction of both MDS and AML in cats.
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Affiliation(s)
- Masaharu Hisasue
- Laboratory of Veterinary Internal Medicine II, School of Veterinary Medicine, Azabu University, Sagamihara City, Kanagawa, Japan
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20
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Cattori V, Tandon R, Riond B, Pepin AC, Lutz H, Hofmann-Lehmann R. The kinetics of feline leukaemia virus shedding in experimentally infected cats are associated with infection outcome. Vet Microbiol 2009; 133:292-6. [DOI: 10.1016/j.vetmic.2008.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 06/17/2008] [Accepted: 07/16/2008] [Indexed: 12/27/2022]
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21
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Review of companion animal viral diseases and immunoprophylaxis. Vaccine 2008; 27:491-504. [PMID: 19041354 PMCID: PMC7130499 DOI: 10.1016/j.vaccine.2008.11.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2008] [Accepted: 11/05/2008] [Indexed: 12/01/2022]
Abstract
In this article we review important established, newly emergent and potential viral diseases of cats, dogs and rabbits. Topics covered include virus epidemiology, disease pathogenesis, existing and prospective immunoprophylaxis against the viruses. For some feline viruses, notably the immunodeficiency virus, leukaemia virus and peritonitis virus, available vaccines are poorly efficacious but there are good prospects for this. A further challenge for the industry is likely to be due to viruses jumping species and the emergence of more virulent variants of established viruses resulting from mutations as has been the case for the canine parvovirus, coronaviruses and feline calicivirus.
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22
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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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23
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24
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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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25
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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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26
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SAKAGUCHI S, BABA K, ISHIKAWA M, YOSHIKAWA R, SHOJIMA T, MIYAZAWA T. Focus Assay on RD114 Virus in QN10S Cells. J Vet Med Sci 2008; 70:1383-6. [PMID: 19122411 DOI: 10.1292/jvms.70.1383] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Shoichi SAKAGUCHI
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
- Obihiro University of Agriculture and Veterinary Medicine
| | - Kenji BABA
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
| | - Mieko ISHIKAWA
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
| | - Rokusuke YOSHIKAWA
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
| | - Takayuki SHOJIMA
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
| | - Takayuki MIYAZAWA
- Laboratory of Viral Pathogenesis, Center for Emerging Virus Research, Institute for Virus Research, Kyoto University
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27
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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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28
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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: 64] [Impact Index Per Article: 3.6] [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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29
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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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30
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Gomes-Keller MA, Gönczi E, Tandon R, Riondato F, Hofmann-Lehmann R, Meli ML, Lutz H. Detection of feline leukemia virus RNA in saliva from naturally infected cats and correlation of PCR results with those of current diagnostic methods. J Clin Microbiol 2006; 44:916-22. [PMID: 16517876 PMCID: PMC1393115 DOI: 10.1128/jcm.44.3.916-922.2006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel diagnostic test for feline leukemia virus (FeLV) RNA in saliva from naturally infected cats is described in this study. We evaluated different diagnostic tests and compared them with the widely used enzyme-linked immunosorbent assay (ELISA) for the detection of p27 in the diagnosis of FeLV. Blood samples from 445 cats were tested for the presence of provirus by real-time PCR and plasma and saliva specimens from those cats were tested for the presence of viral RNA by real-time reverse transcription (RT)-PCR and for the presence of p27 by ELISA. In comparison to conventional ELISA, the diagnostic sensitivity and specificity of the detection of salivary FeLV RNA by real-time RT-PCR were found to be 98.1 and 99.2%, respectively. Detection of viral RNA in saliva had a positive predictive value of 94.6% and a negative predictive value of 99.7%. The kappa value was 0.96, demonstrating an almost perfect agreement between both tests. Furthermore, we confirmed previous results showing that a number of cats which tested negative for the presence of p27 in plasma were in fact positive for the presence of DNA provirus in blood specimens (5.4%). However, 96.4% of these latently infected cats did not shed viral RNA in saliva; therefore, we assume that these cats are of relatively low clinical importance at the time of testing. This study shows considerable diagnostic value of the detection of saliva FeLV RNA in naturally infected cats. This new diagnostic method has advantages over the conventional ELISA, such as less invasive sample collection and no requirement for trained personnel.
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Affiliation(s)
- M A Gomes-Keller
- Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057, Zurich, Switzerland.
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31
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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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32
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Abstract
Molecular technology has given us a greater insight into the aetiology of disease, the functioning of the immune system and the mode of action of veterinary pathogens. The knowledge gained has been used to develop new vaccines with specific, reactive antigens which elicit protective immune mediated responses (humoral and/or cell mediated) in the host. These vaccines should not burden the immune system by initiating responses against non-essential antigens. However, the efficacy of these vaccines is only as good as the delivery technology or route used to present them to the immune system. Some vaccines, traditionally given by the parenteral route, are now given by the natural route; either orally or intranasally. Two major advantages, often interrelated, are the rapid onset of immunity and stimulation of the local, mucosal immunity. These new technologies are now making an impact on current vaccine development. The balance has to be found between what is technologically feasible and what will provide at least as good a protective immunity as current, conventional vaccines. As new and emerging diseases appear globally, new opportunities arise for molecular and conventional technologies to be applied to both the development and delivery of novel vaccines, as well as the improvement of vaccines in current use.
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Affiliation(s)
- W S K Chalmers
- Intervet UK Ltd., Walton Manor, Walton, Milton Keynes, Buckinghamshire MK7 7AJ, UK.
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33
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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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34
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Nagashima N, Hisasue M, Nishigaki K, Miyazawa T, Kano R, Hasegawa A. In vitro selective suppression of feline myeloid colony formation is attributable to molecularly cloned strain of feline leukemia virus with unique long terminal repeat. Res Vet Sci 2005; 78:151-4. [PMID: 15563922 DOI: 10.1016/j.rvsc.2004.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2004] [Indexed: 11/28/2022]
Abstract
Molecularly cloned feline leukemia virus (FeLV)-clone 33 (C-33), derived from a cat with acute myelocytic leukemia (AML), was examined to assess its relation to the pathogenesis of AML and myelodysplastic syndrome (MDS). To evaluate in vitro pathogenicity of FeLV C-33, bone marrow colony-forming assay was performed on marrow cells infected with FeLV C-33 or an FeLV subgroup A strain (61E, a molecularly cloned strain with minimal pathogenicity). The myeloid colony-forming activity of feline bone marrow mononuclear cells infected with FeLV C-33 was significantly lower than that of cells infected with 61E. This suggests that FeLV C-33 has myeloid lineage-specific pathogenicity for cats, and that FeLV C-33 infection is useful as an experimental model for investigating pathogenesis of MDS and AML.
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MESH Headings
- Animals
- Bone Marrow Cells/cytology
- Bone Marrow Cells/virology
- Cat Diseases/virology
- Cats
- Cloning, Molecular
- DNA, Viral/chemistry
- DNA, Viral/genetics
- Leukemia Virus, Feline/genetics
- Leukemia Virus, Feline/pathogenicity
- Leukemia, Myeloid, Acute/pathology
- Leukemia, Myeloid, Acute/veterinary
- Leukemia, Myeloid, Acute/virology
- Myelodysplastic Syndromes/veterinary
- Myelodysplastic Syndromes/virology
- Myeloid Progenitor Cells/cytology
- Myeloid Progenitor Cells/virology
- Polymerase Chain Reaction/veterinary
- Retroviridae Infections/veterinary
- Retroviridae Infections/virology
- Terminal Repeat Sequences
- Tumor Virus Infections/veterinary
- Tumor Virus Infections/virology
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Affiliation(s)
- N Nagashima
- Department of Pathobiology, Nihon University School of Veterinary Medicine, 1866, Kameino, Fujisawa, Kanagawa 252-8510, Japan
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35
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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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36
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Nakata R, Miyazawa T, Shin YS, Watanabe R, Mikami T, Matsuura Y. Reevaluation of host ranges of feline leukemia virus subgroups. Microbes Infect 2003; 5:947-50. [PMID: 12941386 DOI: 10.1016/s1286-4579(03)00180-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We reevaluated the host ranges of feline leukemia virus (FeLV) subgroups A, B and C using pseudotype assays based on recombinant NB-tropic murine leukemia virus, which is not usually blocked after viral entry in mammalian cells. Pseudotype viruses of FeLV-B and -C infected a variety of cell lines from many mammalian species. Unexpectedly, FeLV-A pseudotype viruses of two independent isolates from the UK and US also infected a variety of non-feline cell lines including cells from humans, rabbits, pigs and minks. Moreover, both isolates of FeLV-A productively infected human embryonic kidney 293 and mink Mv-1-Lu cells. We conclude that FeLV-A is not strictly ecotropic.
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Affiliation(s)
- Risa Nakata
- Research Center for Emerging Infectious Diseases, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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37
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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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38
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Addie DD, Radford A, Yam PS, Taylor DJ. Cessation of feline calicivirus shedding coincident with resolution of chronic gingivostomatitis in a cat. J Small Anim Pract 2003; 44:172-6. [PMID: 12703869 DOI: 10.1111/j.1748-5827.2003.tb00140.x] [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: 01/09/2023]
Abstract
Feline calicivirus (FCV) shedding and oral bacterial flora were monitored over a period of 22 months in a case of feline gingivostomatitis (FGS). The cat was treated daily with 50 mg thalidomide capsules by mouth, and 200 mg lactoferrin powder was applied directly to the lesions. Clinical signs began to resolve after 11 months when, in addition to treatment, the diet had been changed to an additive-free cat food supplemented with antioxidant vitamins A, D3 and E. Resolution of clinical signs of FGS coincided with the cessation of FCV shedding, and this is the first report documenting such an association. Which part of the treatment, if any, contributed to the cure requires further investigation.
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Affiliation(s)
- D D Addie
- Department of Veterinary Pathology, University of Glasgow, Bearsden Road, Glasgow G61 1QH
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39
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Affiliation(s)
- Andrew H Sparkes
- The Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk CB8 7UU, UK.
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40
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Flynn JN, Dunham SP, Watson V, Jarrett O. Longitudinal analysis of feline leukemia virus-specific cytotoxic T lymphocytes: correlation with recovery from infection. J Virol 2002; 76:2306-15. [PMID: 11836409 PMCID: PMC135947 DOI: 10.1128/jvi.76.5.2306-2315.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Feline leukemia virus (FeLV) is a common naturally occurring gammaretrovirus of domestic cats that is associated with degenerative diseases of the hematopoietic system, immunodeficiency, and neoplasia. Although the majority of cats exposed to FeLV develop a transient infection and recover, a proportion of cats become persistently viremic and many subsequently develop fatal diseases. To define the dominant host immune effector mechanisms responsible for the outcome of infection, we studied the longitudinal changes in FeLV-specific cytotoxic T lymphocytes (CTLs) in a group of naïve cats following oronasal exposure to FeLV. Using (51)Cr release assays to measure ex vivo virus-specific cytotoxicity, the emerging virus-specific CTL response was correlated with modulations in viral burden as assessed by detection of infectious virus, FeLV p27 capsid antigen, and proviral DNA in the blood. High levels of circulating FeLV-specific effector CTLs appeared before virus neutralizing antibodies in cats that recovered from exposure to FeLV. In contrast, persistent viremia was associated with a silencing of virus-specific humoral and cell-mediated host immune effector mechanisms. A single transfer of between 2 x 10(7) and 1 x 10(8) autologous, antigen-activated lymphoblasts was associated with a downmodulation in viral burden in vivo. The results suggest an important role for FeLV-specific CTLs in retroviral immunity and demonstrate the potential to modulate disease outcome by the adoptive transfer of antigen-specific T cells in vivo.
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Affiliation(s)
- J Norman Flynn
- Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, Glasgow G61 1QH, Scotland.
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41
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Hartmann K, Werner RM, Egberink H, Jarrett O. Comparison of six in-house tests for the rapid diagnosis of feline immunodeficiency and feline leukaemia virus infections. Vet Rec 2001; 149:317-20. [PMID: 11583125 DOI: 10.1136/vr.149.11.317] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Six rapid tests for the diagnosis of feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infections which have recently been introduced in Europe for use in small animal practice were compared. Eight hundred serum samples were tested and those reacting FIV-positive in at least one of the tests were confirmed by Western blot, and those reacting FeLV-positive were confirmed by virus isolation. The specificity and sensitivity of each test and the quality of the results produced were compared.
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Affiliation(s)
- K Hartmann
- Medizinische Tierklinik, München, Germany
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42
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Hanlon L, Argyle D, Bain D, Nicolson L, Dunham S, Golder MC, McDonald M, McGillivray C, Jarrett O, Neil JC, Onions DE. Feline leukemia virus DNA vaccine efficacy is enhanced by coadministration with interleukin-12 (IL-12) and IL-18 expression vectors. J Virol 2001; 75:8424-33. [PMID: 11507187 PMCID: PMC115087 DOI: 10.1128/jvi.75.18.8424-8433.2001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2001] [Accepted: 06/07/2001] [Indexed: 11/20/2022] Open
Abstract
The expectation that cell-mediated immunity is important in the control of feline leukemia virus (FeLV) infection led us to test a DNA vaccine administered alone or with cytokines that favored the development of a Th1 immune response. The vaccine consisted of two plasmids, one expressing the gag/pol genes and the other expressing the env gene of FeLV-A/Glasgow-1. The genetic adjuvants were plasmids encoding the feline cytokines interleukin-12 (IL-12), IL-18, or gamma interferon (IFN-gamma). Kittens were immunized by three intramuscular inoculations of the FeLV DNA vaccine alone or in combination with plasmids expressing IFN-gamma, IL-12, or both IL-12 and IL-18. Control kittens were inoculated with empty plasmid. Following immunization, anti-FeLV antibodies were not detected in any kitten. Three weeks after the final immunization, the kittens were challenged by the intraperitoneal inoculation of FeLV-A/Glasgow-1 and were then monitored for a further 15 weeks for the presence of virus in plasma and, at the end of the trial, for latent virus in bone marrow. The vaccine consisting of FeLV DNA with the IL-12 and IL-18 genes conferred significant immunity, protecting completely against transient and persistent viremia, and in five of six kittens protecting against latent infection. None of the other vaccines provided significant protection.
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Affiliation(s)
- L Hanlon
- Department of Veterinary Pathology, University of Glasgow, Bearsden, Glasgow G61 1QH, United Kingdom.
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43
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Abstract
This review deals briefly with some key developments in veterinary vaccinology, lists the types of vaccines that are used for vaccinations commonly performed in food animals as well as in companion animals, and indicates that the practising veterinarian can select the best vaccine by comparing the results of efficacy studies. Diva (Differentiating Infected from Vaccinated Animals; also termed marker) vaccines and companion diagnostic tests have been developed that can be used for progammes aimed to control or eradicate virus infections. Vaccine-induced herd immunity, which can be measured relatively easily when diva vaccines are used, is a crucial issue in such programmes. Current vaccine research follows many routes towards novel vaccines, which can be divided into non-replicating ('killed') and replicating ('live') vaccines. Promising trends are the development of DNA vaccination, vector vaccines, and attenuation of DNA and RNA viruses by DNA technology. The lack of (in vitro) correlates of vaccine protection markedly hampers progress in vaccine research. Various characteristics of an 'ideal' vaccine are listed, such as multivalency and the induction of lifelong immunity after one non-invasive administration in animals with maternal immunity. Future research should be aimed at developing vaccines that approach the ideal as closely as possible and which are directed against diseases not yet controlled by vaccination and against newly emerging diseases.
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Affiliation(s)
- J T van Oirschot
- Institute for Animal Science and Health (ID-Lelystad), The Netherlands
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44
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Hofmann-Lehmann R, Huder JB, Gruber S, Boretti F, Sigrist B, Lutz H. Feline leukaemia provirus load during the course of experimental infection and in naturally infected cats. J Gen Virol 2001; 82:1589-1596. [PMID: 11413369 DOI: 10.1099/0022-1317-82-7-1589] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Feline leukaemia virus (FeLV) infection in domestic cats can vary in its outcome (persistent, transient, no infection) for reasons that are not entirely known. It was hypothesized that the initial virus and provirus load could significantly influence the course of retrovirus infection. To determine the role of provirus loads, two methods of PCR, a nested PCR and a fluorogenic probe-based (TaqMan) real-time quantitative PCR, which were specific to the U3 region of FeLV-A were established. FeLV provirus in naturally and experimentally infected cats was then measured. Only 3 weeks after experimental FeLV-A infection, persistently infected cats demonstrated higher provirus loads and lower humoral immune responses than cats that had overcome antigenaemia. Lower initial provirus loads were associated with successful humoral immune responses. Unexpectedly, provirus in the buffy-coat cells of two cats that tested negative for the p27 antigen (a marker for viraemia) was also detected. In 597 Swiss cats, comparison of p27 antigen levels with PCR results revealed broad agreement. However, similar to the experimental situation, a significant number of animals (10%) was negative for the p27 antigen and FeLV-positive by PCR. These cats had a mean provirus load 300-fold lower than that of animals testing positive for the p27 antigen. In conclusion, an association between the provirus load and the outcome of FeLV infection was found. Detection of provirus carriers should contribute to further the control of FeLV. In addition, quantification of provirus loads will lead to a better understanding of FeLV pathogenesis and anti-retrovirus protective mechanisms.
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Affiliation(s)
- Regina Hofmann-Lehmann
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
| | - Jon B Huder
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
| | - Sabine Gruber
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
| | - Felicitas Boretti
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
| | - Brigitte Sigrist
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
| | - Hans Lutz
- Clinical Laboratory, Department of Internal Veterinary Medicine, Faculty of Veterinary Medicine, University of Zurich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland1
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45
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Flynn JN, Hanlon L, Jarrett O. Feline leukaemia virus: protective immunity is mediated by virus-specific cytotoxic T lymphocytes. Immunology 2000; 101:120-5. [PMID: 11012762 PMCID: PMC2327065 DOI: 10.1046/j.1365-2567.2000.00089.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Feline leukaemia virus (FeLV) nucleic acid vaccination of domestic cats affords protection against viraemia and the development of latency without inducing antiviral antibodies.1 To determine the contribution of cell-mediated immunity to the control of virus replication and clearance from the host, FeLV-specific cytotoxic T lymphocyte (CTL) responses were compared in vaccine-protected, transiently viraemic, and persistently viraemic cats. Vaccinal immunity was associated with the detection of higher levels of virus-specific effector CTL in the peripheral blood and lymphoid organs to FeLV Gag/Pro and Env antigens than those observed in unvaccinated control, persistently viraemic cats (P<0.001). Likewise, higher levels of virus-specific CTLs were also observed in transiently viraemic cats which recovered following exposure to FeLV. In cats that controlled their infection, recognition of Gag/Pro antigens was significantly higher than the recognition of Env antigens. This is the first report highlighting the very significant role that virus-specific CTL have in determining the outcome of FeLV infection in either vaccinated cats or cats recovering naturally from FeLV exposure.
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Affiliation(s)
- J N Flynn
- Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow, Glasgow, UK
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46
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Addie DD, Dennis JM, Toth S, Callanan JJ, Reid S, Jarrett O. Long-term impact on a closed household of pet cats of natural infection with feline coronavirus, feline leukaemia virus and feline immunodeficiency virus. Vet Rec 2000; 146:419-24. [PMID: 10811262 DOI: 10.1136/vr.146.15.419] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A closed household of 26 cats in which feline coronavirus (FCoV), feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) were endemic was observed for 10 years. Each cat was seropositive for FCoV on at least one occasion and the infection was maintained by reinfection. After 10 years, three of six surviving cats were still seropositive. Only one cat, which was also infected with FIV, developed feline infectious peritonitis (FIP). Rising anti-FCoV antibody titres did not indicate that the cat would develop FIP. The FeLV infection was self-limiting because all seven of the initially viraemic cats died within five years and the remainder were immune. However, FeLV had the greatest impact on mortality. Nine cats were initially FIV-positive and six more cats became infected during the course of the study, without evidence of having been bitten. The FIV infection did not adversely affect the cats' life expectancy.
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Affiliation(s)
- D D Addie
- Department of Veterinary Pathology, University of Glasgow Veterinary School, Bearsden
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47
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Gueguen S, Martin V, Bonnet L, Saunier D, Mähl P, Aubert A. Safety and efficacy of a recombinant FeLV vaccine combined with a live feline rhinotracheitis, calicivirus and panleukopenia vaccine. Vet Rec 2000; 146:380-1. [PMID: 10803986 DOI: 10.1136/vr.146.13.380-b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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48
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Baumann JG, Günzburg WH, Salmons B. CrFK feline kidney cells produce an RD114-like endogenous virus that can package murine leukemia virus-based vectors. J Virol 1998; 72:7685-7. [PMID: 9696876 PMCID: PMC110043 DOI: 10.1128/jvi.72.9.7685-7687.1998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The feline kidney cell line CrFK is used extensively for viral infectivity assays and for study of the biology of various retroviruses and derived vectors. We demonstrate the production of an endogenous, RD114-like, infectious retrovirus from CrFK cells. This virus also is shown to efficiently package Moloney murine leukemia virus vectors.
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Affiliation(s)
- J G Baumann
- Institute of Virology, University of Veterinary Sciences, A-1210 Vienna, Austria
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49
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Robinson A, DeCann K, Aitken E, Gruffydd-Jones TJ, Sparkes AH, Werret G, Harbour DA. Comparison of a rapid immunomigration test and ELISA for FIV antibody and FeLV antigen testing in cats. Vet Rec 1998; 142:491-2. [PMID: 9612917 DOI: 10.1136/vr.142.18.491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- A Robinson
- Feline Centre, Department of Clinical Veterinary Science, Langford, Bristol
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50
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Ramsey IK, Spibey N, Jarrett O. The receptor binding site of feline leukemia virus surface glycoprotein is distinct from the site involved in virus neutralization. J Virol 1998; 72:3268-77. [PMID: 9525654 PMCID: PMC109800 DOI: 10.1128/jvi.72.4.3268-3277.1998] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The external surface glycoprotein (SU) of feline leukemia virus (FeLV) contains sites which define the viral subgroup and induce virus-neutralizing antibodies. The subgroup phenotypic determinants have been located to a small variable region, VR1, towards the amino terminus of SU. The sites which function as neutralizing epitopes in vivo are unknown. Recombinant SU proteins were produced by using baculoviruses that contained sequences encoding the SUs of FeLV subgroup A (FeLV-A), FeLV-C, and two chimeric FeLVs (FeLV-215 and FeLV-VC) in which the VR1 domain of FeLV-A had been replaced by the corresponding regions of FeLV-C isolates. The recombinant glycoproteins, designated Bgp70-A, -C, -215, and -VC, respectively, were similar to their wild-type counterparts in several immunoblots and inhibited infection of susceptible cell lines in a subgroup-specific manner. Thus, Bgp70-A interfered with infection by FeLV-A, whereas Bgp70-C, -VC, and -215 did not. Conversely, Bgp70-C, -VC, and -215 blocked infection with FeLV-C, while Bgp70-A had no effect. These results indicate that the site on SU which binds to the FeLV cell surface receptor was preserved in the recombinant glycoproteins. It was also found that the recombinant proteins were able to bind naturally occurring neutralizing antibodies. Bgp70-A, -VC, and -215 interfered with the action of anti-FeLV-A neutralizing antibodies, whereas Bgp70-C did not. Furthermore, Bgp70-C interfered with the action of anti-FeLV-C neutralizing antibodies, while the other proteins did not. These results indicate that the neutralizing epitope(s) of FeLV SU lies outside the subgroup-determining VR1 domain.
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Affiliation(s)
- I K Ramsey
- Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom
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