55 results on '"Leukemia, Feline prevention & control"'
Search Results
2. 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).
- Author
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Westman M, Norris J, Malik R, Hofmann-Lehmann R, Parr YA, Armstrong E, McDonald M, Hall E, Sheehy P, and Hosie MJ
- Subjects
- Animals, Antibodies, Neutralizing blood, Antibodies, Viral blood, Australia, Cats, Enzyme-Linked Immunosorbent Assay, Gene Products, gag immunology, Leukemia Virus, Feline genetics, Leukemia Virus, Feline isolation & purification, Leukemia, Feline diagnosis, Vaccines, Inactivated administration & dosage, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccination veterinary, Viral Vaccines administration & dosage
- 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.- Published
- 2021
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3. The Diagnosis of Feline Leukaemia Virus (FeLV) Infection in Owned and Group-Housed Rescue Cats in Australia.
- Author
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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, and Hosie M
- Subjects
- Animals, Antibodies, Viral blood, Australia epidemiology, Cats, Cross-Sectional Studies, DNA, Viral blood, Leukemia, Feline diagnosis, Leukemia, Feline epidemiology, Leukemia, Feline prevention & control, Retroviridae Infections diagnosis, Retroviridae Infections epidemiology, Retroviridae Infections prevention & control, Viral Load veterinary, Cat Diseases virology, Leukemia Virus, Feline immunology, Leukemia Virus, Feline isolation & purification, Leukemia, Feline virology, Retroviridae Infections veterinary
- 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.
- Published
- 2019
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4. Diagnosing feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) infection: an update for clinicians.
- Author
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Westman ME, Malik R, and Norris JM
- Subjects
- Animals, Antibodies, Viral analysis, Antibodies, Viral blood, Australia epidemiology, Cats, Feline Acquired Immunodeficiency Syndrome epidemiology, Feline Acquired Immunodeficiency Syndrome prevention & control, Immunodeficiency Virus, Feline immunology, Leukemia Virus, Feline immunology, Leukemia, Feline epidemiology, Leukemia, Feline prevention & control, Point-of-Care Systems, Polymerase Chain Reaction, Retroviridae Proteins, Oncogenic immunology, Saliva virology, Sensitivity and Specificity, Viral Vaccines immunology, Feline Acquired Immunodeficiency Syndrome diagnosis, Immunodeficiency Virus, Feline isolation & purification, Leukemia Virus, Feline isolation & purification, Leukemia, Feline diagnosis
- Abstract
With the commercial release in Australia in 2004 of a vaccine against feline immunodeficiency virus (FIV; Fel-O-Vax FIV®), the landscape for FIV diagnostics shifted substantially. Point-of-care (PoC) antibody detection kits, which had been the mainstay for diagnosing FIV infection since the early 1990s, were no longer considered accurate to use in FIV-vaccinated cats, because of the production of vaccine-induced antibodies that were considered indistinguishable from those produced in natural FIV infections. Consequently, attention shifted to alternative diagnostic methods such as nucleic acid detection. However, over the past 5 years we have published a series of studies emphasising that FIV PoC test kits vary in their methodology, resulting in differing accuracy in FIV-vaccinated cats. Importantly, we demonstrated that two commercially available FIV antibody test kits (Witness™ and Anigen Rapid™) were able to accurately distinguish between FIV-vaccinated and FIV-infected cats, concluding that testing with either kit offers an alternative to PCR testing. This review summarises pertinent findings from our work published in a variety of peer-reviewed research journals to inform veterinarians (particularly veterinarians in Australia, New Zealand and Japan, where the FIV vaccine is currently commercially available) about how the approach to the diagnosis of FIV infection has shifted. Included in this review is our work investigating the performance of three commercially available FIV PoC test kits in FIV-vaccinated cats and our recommendations for the diagnosis of FIV infection; the effect of primary FIV vaccination (three FIV vaccines, 4 weeks apart) on PoC test kit performance; our recommendations regarding annual testing of FIV-vaccinated cats to detect 'vaccine breakthroughs'; and the potential off-label use of saliva for the diagnosis of FIV infection using some FIV PoC test kits. We also investigated the accuracy of the same three brands of test kits for feline leukaemia virus (FeLV) diagnosis, using both blood and saliva as diagnostic specimens. Based on these results, we discuss our recommendations for confirmatory testing when veterinarians are presented with a positive FeLV PoC test kit result. Finally, we conclude with our results from the largest and most recent FIV and FeLV seroprevalence study conducted in Australia to date., (© 2019 Australian Veterinary Association.)
- Published
- 2019
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5. Comparing the efficacy of FeLV vaccines: comment on: Stuke, K. et al. Efficacy of an inactivated FeLV vaccine compared to a recombinant FeLV vaccine in minimum age cats following virulent FeLV challenge. Vaccine 2014;32(22):2599-603.
- Author
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Hofmann-Lehmann R, Levy LS, and Willett BJ
- Subjects
- Animals, Antigens, Viral blood, Gene Products, gag blood, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic administration & dosage, Vaccination veterinary, Viral Vaccines administration & dosage
- Published
- 2015
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6. In response to letter to the editor (Regina Hofmann-Lehmann, Laura S. Levy and Brian Willett)--Comparing the efficacy of FeLV vaccines.
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Stuke K, King V, Southwick K, Stoeva MI, Thomas A, and Winkler MT
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- Animals, Antigens, Viral blood, Gene Products, gag blood, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic administration & dosage, Vaccination veterinary, Viral Vaccines administration & dosage
- Published
- 2015
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7. Efficacy of an inactivated FeLV vaccine compared to a recombinant FeLV vaccine in minimum age cats following virulent FeLV challenge.
- Author
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Stuke K, King V, Southwick K, Stoeva MI, Thomas A, and Winkler MT
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- Animals, Bone Marrow Cells virology, Cats, DNA, Viral isolation & purification, Leukemia Virus, Feline, Random Allocation, Vaccines, Inactivated administration & dosage, Vaccines, Synthetic administration & dosage, Antigens, Viral blood, Gene Products, gag blood, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic administration & dosage, Vaccination veterinary, Viral Vaccines administration & dosage
- Abstract
The aim of the study was to determine the efficacy of an inactivated feline leukemia virus (FeLV) vaccine (Versifel(®) FeLV, Zoetis.) compared to a recombinant FeLV vaccine (Purevax(®) FeLV, Merial Animal Health) in young cats, exposed under laboratory conditions to a highly virulent challenge model. The study was designed to be consistent with the general immunogenicity requirements of the European Pharmacopoeia 6.0 Monograph 01/2008:1321-Feline Leukaemia Vaccine (Inactivated) with the exception that commercial-strength vaccines were assessed. Fifty seronegative cats (8-9 weeks old) were vaccinated subcutaneously on two occasions, three weeks apart, with either placebo (treatment group T01), Versifel FeLV Vaccine (treatment group T02), or Purevax FeLV Vaccine (treatment group T03) according to the manufacturer's directions. Cats were challenged three weeks after the second vaccination with a virulent FeLV isolate (61E strain). Persistent FeLV antigenemia was determined from 3 to 15 weeks postchallenge. Bone marrow samples were tested for the presence of FeLV proviral DNA to determine FeLV latent infection. At week 15 after challenge with the virulent FeLV 61E strain, the Versifel FeLV Vaccine conferred 89.5% protection against FeLV persistent antigenemia and 94.7% protection against FeLV proviral DNA integration in bone marrow cells. In comparison, the Purevax FeLV Vaccine conferred 20% protection against FeLV persistent antigenemia and 35% protection against FeLV proviral DNA integration in bone marrow cells following challenge. The data from this study show that the Versifel FeLV Vaccine was efficacious in preventing both FeLV persistent p27 antigenemia and FeLV proviral DNA integration in bone marrow cells of cats challenged with this particular challenge model under laboratory conditions and provided better protection than Purevax FeLV in this experimental challenge model with highly virulent FeLV., (Copyright © 2014 Elsevier Ltd. All rights reserved.)
- Published
- 2014
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8. A targeted mutation within the feline leukemia virus (FeLV) envelope protein immunosuppressive domain to improve a canarypox virus-vectored FeLV vaccine.
- Author
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Schlecht-Louf G, Mangeney M, El-Garch H, Lacombe V, Poulet H, and Heidmann T
- Subjects
- Animals, Canarypox virus metabolism, Cats, Female, Gene Products, env administration & dosage, Gene Products, env genetics, Genetic Vectors genetics, Genetic Vectors metabolism, Immunosuppressive Agents administration & dosage, Immunosuppressive Agents immunology, Interferons genetics, Interferons immunology, Interleukin-10 genetics, Interleukin-10 immunology, Leukemia Virus, Feline chemistry, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Leukemia, Feline virology, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Protein Structure, Tertiary, Retroviridae Proteins, Oncogenic administration & dosage, Retroviridae Proteins, Oncogenic chemistry, Retroviridae Proteins, Oncogenic immunology, Viral Vaccines administration & dosage, Viral Vaccines chemistry, Viral Vaccines immunology, Canarypox virus genetics, Gene Products, env chemistry, Gene Products, env immunology, Immunosuppressive Agents chemistry, Leukemia Virus, Feline genetics, Leukemia, Feline immunology, Mutation, Missense, Retroviridae Proteins, Oncogenic genetics, Viral Vaccines genetics
- Abstract
We previously delineated a highly conserved immunosuppressive (IS) domain within murine and primate retroviral envelope proteins that is critical for virus propagation in vivo. The envelope-mediated immunosuppression was assessed by the ability of the proteins, when expressed by allogeneic tumor cells normally rejected by engrafted mice, to allow these cells to escape, at least transiently, immune rejection. Using this approach, we identified key residues whose mutation (i) specifically abolishes immunosuppressive activity without affecting the "mechanical" function of the envelope protein and (ii) significantly enhances humoral and cellular immune responses elicited against the virus. The objective of this work was to study the immunosuppressive activity of the envelope protein (p15E) of feline leukemia virus (FeLV) and evaluate the effect of its abolition on the efficacy of a vaccine against FeLV. Here we demonstrate that the FeLV envelope protein is immunosuppressive in vivo and that this immunosuppressive activity can be "switched off" by targeted mutation of a specific amino acid. As a result of the introduction of the mutated envelope sequence into a previously well characterized canarypox virus-vectored vaccine (ALVAC-FeLV), the frequency of vaccine-induced FeLV-specific gamma interferon (IFN-γ)-producing cells was increased, whereas conversely, the frequency of vaccine-induced FeLV-specific interleukin-10 (IL-10)-producing cells was reduced. This shift in the IFN-γ/IL-10 response was associated with a higher efficacy of ALVAC-FeLV against FeLV infection. This study demonstrates that FeLV p15E is immunosuppressive in vivo, that the immunosuppressive domain of p15E can modulate the FeLV-specific immune response, and that the efficacy of FeLV vaccines can be enhanced by inhibiting the immunosuppressive activity of the IS domain through an appropriate mutation.
- Published
- 2014
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9. Difficulties in demonstrating long term immunity in FeLV vaccinated cats due to increasing age-related resistance to infection.
- Author
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Wilson S, Greenslade J, Saunders G, Holcroft C, Bruce L, Scobey A, Childers T, Sture G, and Thompson J
- Subjects
- Animals, Antigens, Viral, Cats, Proliferating Cell Nuclear Antigen blood, Vaccines, Inactivated immunology, Aging immunology, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Viral Vaccines immunology
- Abstract
Background: Feline leukaemia virus (FeLV) is a pathogen causing fatal illness in cats worldwide, and as such there is a high demand for products to protect against disease. The duration of immunity provided by an inactivated FeLV vaccine, Versifel FeLV, when administered to cats of the target age was determined. Kittens received two vaccinations when aged 7 to 9 weeks old, and were subsequently challenged up to 36 months later with the FeLV-A Glasgow isolate., Results: In all studies, all of the younger aged control kittens showed persistent FeLV p27 antigenaemia confirming that the challenge virus was severe and efficacious. In contrast, the control cats did not show the required level of persistent antigenaemia, with a maximum of 45% cats affected in the middle duration study and only 10% in the longer study. However, apart from one animal in the short duration study, all of the cats vaccinated with Versifel FeLV were negative for persistent antigenaemia and can be considered treatment successes., Conclusion: In conclusion, we have shown that although age-related resistance to infection with a virulent FeLV challenge is evident from as early as 10 months of age, vaccination with Versifel FeLV may aid in the protection of cats from FeLV related disease up to three years after primary vaccination as kittens.
- Published
- 2012
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10. Antibody response to vaccines for rhinotracheitis, caliciviral disease, panleukopenia, feline leukemia, and rabies in tigers (Panthera tigris) and lions (Panthera leo).
- Author
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Risi E, Agoulon A, Allaire F, Le Dréan-Quénec'hdu S, Martin V, and Mahl P
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- Animals, Animals, Zoo, Caliciviridae Infections prevention & control, Cats, Dose-Response Relationship, Immunologic, Feline Panleukopenia immunology, Leukemia, Feline immunology, Leukemia, Feline prevention & control, Rabies prevention & control, Rabies veterinary, Serologic Tests, Vaccination, Viral Vaccines administration & dosage, Antibodies, Viral blood, Caliciviridae Infections veterinary, Feline Panleukopenia prevention & control, Lions, Tigers, Viral Vaccines immunology
- 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.
- Published
- 2012
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11. [FeLV infection in the cat: clinically relevant aspects].
- Author
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Boretti FS, Lutz H, and Hofmann-Lehmann R
- Subjects
- Animals, Cats, Leukemia Virus, Feline, Leukemia, Feline prevention & control, Leukemia, Feline transmission, Viral Vaccines administration & dosage, Leukemia, Feline diagnosis, Leukemia, Feline pathology
- Abstract
The feline leukemia virus (FeLV) is a retrovirus of the domestic cat that was described almost 50 years ago. The FeLV-infection may lead to fatal diseases in domestic and small wild cats. The use of efficacious diagnostics assays and vaccines led to a reduction of the FeLV prevalence; however, FeLV still poses a problem for the cat presented with the infection. This article aims to describe recent developments in diagnostics and findings in the infection pathogenesis that are clinically relevant.
- Published
- 2011
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12. Protection against feline leukemia virus challenge for at least 2 years after vaccination with an inactivated feline leukemia virus vaccine.
- Author
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Jirjis FF, Davis T, Lane J, Carritt K, Sweeney D, Williams J, and Wasmoen T
- Subjects
- Animals, Cats, Specific Pathogen-Free Organisms, Vaccination, Vaccines, Inactivated immunology, Viremia, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Viral Vaccines immunology
- Abstract
Twelve cats were vaccinated at 8 and 11 weeks of age with a commercially available inactivated FeLV vaccine (Nobivac FeLV, Intervet/Schering-Plough Animal Health). Eleven cats served as age-matched, placebo-vaccinated controls. All cats were kept in isolation for 2 years after vaccination and were then challenged with virulent FeLV to evaluate vaccine efficacy and duration of immunity. Cats were monitored for 12 weeks after challenge for development of persistent viremia using a commercial FeLV p27 ELISA. Persistent viremia developed in all 11 (100%) of the control cats, whereas 10 of 12 (83%) vaccinated cats were fully protected from persistent viremia following challenge. The results demonstrate that the vaccine used in this study protects cats from persistent FeLV viremia for at least 2 years after vaccination.
- Published
- 2010
13. Feline leukaemia. ABCD guidelines on prevention and management.
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Lutz H, Addie D, Belák S, Boucraut-Baralon C, Egberink H, Frymus T, Gruffydd-Jones T, Hartmann K, Hosie MJ, Lloret A, Marsilio F, Pennisi MG, Radford AD, Thiry E, Truyen U, and Horzinek MC
- Subjects
- Animals, Cats, Diagnosis, Differential, False Positive Reactions, Leukemia, Feline diagnosis, Leukemia, Feline therapy, Leukemia, Feline transmission, Societies, United States, Viremia veterinary, Leukemia, Feline prevention & control, Practice Guidelines as Topic, Vaccination veterinary, Veterinary Medicine standards, Viral Vaccines administration & dosage
- Abstract
Overview: Feline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines., Infection: Transmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30-40% will develop persistent viraemia, 30-40% show transient viraemia and 20-30% seroconvert. Young kittens are especially susceptible to FeLV infection., Disease Signs: The most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2-3 years., Diagnosis: In low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested., Disease Management: Supportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host., Vaccination Recommendations: All cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8-9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3-4 years of age, a booster every 2-3 years suffices, in view of the significantly lower susceptibility of older cats.
- Published
- 2009
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14. Combined administration in a single injection of a feline multivalent modified live vaccine against FHV, FCV, and FPLV together with a recombinant FeLV vaccine is both safe and efficacious for all four major feline viral pathogens.
- Author
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Kanellos T, Sutton DJ, Salisbury CF, and Chalmers WS
- Subjects
- Animals, Caliciviridae Infections immunology, Caliciviridae Infections prevention & control, Calicivirus, Feline immunology, Cat Diseases immunology, Cats, Feline Panleukopenia immunology, Feline Panleukopenia Virus immunology, Female, Herpesviridae immunology, Herpesviridae Infections immunology, Herpesviridae Infections prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline immunology, Male, Safety, Treatment Outcome, Vaccines, Attenuated, Vaccines, Combined, Viral Vaccines adverse effects, Caliciviridae Infections veterinary, Cat Diseases prevention & control, Feline Panleukopenia prevention & control, Herpesviridae Infections veterinary, Leukemia, Feline prevention & control, Viral Vaccines administration & dosage
- Abstract
Nobivac Tricat, a lyophilised trivalent modified live attenuated vaccine is routinely used to protect cats against three commonly diagnosed feline viral pathogens namely herpesvirus, calicivirus and panleukopenia virus. The recognition of feline leukaemia virus (FeLV) as an important viral pathogen has prompted the development of an efficacious liquid recombinant subunit FeLV vaccine (p45 envelope protein). Lyophilised Tricat vaccine was dissolved in the liquid FeLV vaccine and no detectable deleterious effect on the titre of any of the live virus components was observed after 2h incubation. In vivo studies where the vaccines were mixed in the same syringe prior to inoculation showed no alteration to the safety profile assessed by repeat and overdose studies. Serological comparisons of the modified live viral antibody titres showed no evidence of reduced responses following administration of the mixed products. Challenge studies using pathogenic herpesvirus and FeLV revealed no difference in the degree of clinical protection. This paper shows that neither safety nor efficacy is adversely affected as a result of mixing the two vaccines.
- Published
- 2008
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15. How molecular methods change our views of FeLV infection and vaccination.
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Hofmann-Lehmann R, Cattori V, Tandon R, Boretti FS, Meli ML, Riond B, and Lutz H
- Subjects
- Animals, Antigens, Viral blood, Carrier State immunology, Carrier State veterinary, Carrier State virology, Cats, Leukemia, Feline diagnosis, Leukemia, Feline immunology, Leukemia, Feline prevention & control, Proviruses immunology, RNA, Viral chemistry, RNA, Viral genetics, Reverse Transcriptase Polymerase Chain Reaction veterinary, Viral Load veterinary, Leukemia Virus, Feline genetics, Leukemia, Feline virology
- Abstract
FeLV was discovered 40 years ago and vaccines have been commercially available for almost two decades. So far, most FeLV pathogenesis and vaccine studies were conducted assaying parameters, such as virus isolation and antigen detection. Accordingly, regressive infection was characterized by transient or undetectable viremia, while persistent viremia is typically observed in cats with progressive infection. Using real-time polymerase chain reaction assays, the spectrum of host response categories to FeLV infection was recently refined by investigating proviral and plasma viral RNA loads. Cats believed to be immune to FeLV infection were found to turn provirus-positive after virus exposure. Moreover, efficacious FeLV vaccines were found unable to prevent provirus-integration and minimal viral replication. Remarkably, no difference was found in initial proviral and plasma viral RNA loads between cats with different infection outcomes. Only subsequently, the infection outcome is associated with FeLV loads. FeLV provirus was found to persist for years; reoccurrence of viremia and disease development was observed in some cats. Thus, aviremic provirus-positive cats are FeLV carriers and, following reactivation, may act as an infection source. However, integrated viral DNA may also be essential for solid protection and long-lasting maintenance of protective immunity. In conclusion, real-time TaqMan PCR and RT-PCR assays are highly sensitive and specific. They yield a more sensitive measure for FeLV exposure than antigen detection, virus isolation or immunofluoresence assays. We recommend the use of real-time PCR assays to identify FeLV exposed cats, particularly in catteries, and investigate obscure clinical cases that may be FeLV-associated. The use of sensitive molecular methods will contribute to a more in-depth understanding of the FeLV pathogenesis.
- Published
- 2008
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16. Thoughts on the 2006 feline vaccine panel report.
- Author
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Norsworthy GD
- Subjects
- Animal Husbandry methods, Animals, Bites and Stings veterinary, Cats, Leukemia, Feline transmission, Risk Factors, Vaccination standards, Feline Acquired Immunodeficiency Syndrome prevention & control, Leukemia, Feline prevention & control, Vaccination veterinary, Vaccines
- Published
- 2007
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17. Protection from challenge following administration of a canarypox virus-vectored recombinant feline leukemia virus vaccine in cats previously vaccinated with a killed virus vaccine.
- Author
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Grosenbaugh DA, Leard T, and Pardo MC
- Subjects
- Animals, Canarypox virus, Cats, Immunization Schedule, Injections, Subcutaneous veterinary, Prospective Studies, Retroviridae Proteins, Oncogenic administration & dosage, Specific Pathogen-Free Organisms, Treatment Outcome, Vaccination methods, Vaccines, Inactivated, Vaccines, Synthetic, Viral Vaccines administration & dosage, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic immunology, Vaccination veterinary, Viral Vaccines immunology
- Abstract
Objective: To compare protection against FeLV challenge obtained following administration of 2 doses of an adjuvanted, chemically inactivated, whole FeLV (FeLV-k) vaccine with protection obtained following administration of 1 dose of an FeLV-k vaccine followed by 1 dose of a canarypox virus-vectored recombinant FeLV (rCP-FeLV) vaccine., Design: Prospective study., Animals: Thirty-two 9-week-old domestic shorthair cats., Procedure: Cats received 2 doses of the FeLV-k vaccine SC, 21 days apart (n = 11); 1 dose of the FeLV-k vaccine SC and, 21 days later, 1 dose of the rCP-FeLV vaccine transdermally (11); or 2 doses of physiologic saline (0.9% NaCl) solution (control; 10). Four weeks after the second vaccine dose, all cats were challenged with FeLV by means of oronasal administration. Blood samples were collected at weekly intervals beginning 21 days after challenge, and serum was tested for FeLV antigen., Results: All 10 control cats became persistently infected (ie, FeLV antigen detected in > or = 3 consecutive serum samples) following FeLV challenge, whereas only 1 of 11 cats that received 2 doses of the FeLV-k vaccine and none of the 11 cats that received 1 dose of the FeLV-k vaccine and 1 dose of the rCP-FeLV vaccine did., Conclusions and Clinical Relevance: Results suggest that protection against FeLV challenge obtained following SC administration of a single dose of an FeLV-k vaccine followed, 21 days later, by transdermal administration of a single dose of an rCP-FeLV vaccine was similar to that obtained following SC administration of 2 doses of the FeLV-k vaccine 21 days apart.
- Published
- 2006
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18. Feline B7.1 and B7.2 proteins produced from swinepox virus vectors are natively processed and biologically active: potential for use as nonchemical adjuvants.
- Author
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Winslow BJ, Kalabat DY, Brown SM, Cochran MD, and Collisson EW
- Subjects
- Animals, Antigens, CD, Antigens, Differentiation, B7-1 Antigen genetics, B7-2 Antigen genetics, CTLA-4 Antigen, Cats, Cell Line, Gene Products, env metabolism, Gene Products, gag metabolism, Genetic Vectors, Humans, Immunoconjugates, Interleukin-2 biosynthesis, Jurkat Cells, Leukemia, Feline prevention & control, Lymphocyte Activation, Poxviridae Infections immunology, Virus Replication, Adjuvants, Immunologic, B7-1 Antigen immunology, B7-2 Antigen immunology, Poxviridae Infections veterinary, Suipoxvirus immunology
- Abstract
Costimulatory ligands, B7.1 and B7.2, have been incorporated into viral and DNA vectors as potential nonchemical adjuvants to enhance CTL and humoral immune responses against viral pathogens. In addition, soluble B7 proteins, minus their transmembrane and cytoplasmic domains, have been shown to block the down regulation of T-cell activation through blockade of B7/CTLA-4 interactions in mouse tumor models. Recently, we developed swinepox virus (SPV) vectors for delivery of feline leukemia antigens for vaccine use in cats [Winslow, B.J., Cochran, M.D., Holzenburg, A., Sun, J., Junker, D.E., Collisson, E.W., 2003. Replication and expression of a swinepox virus vector delivering feline leukemia virus Gag and Env to cell lines of swine and feline origin. Virus Res. 98, 1-15]. To explore the use of feline B7.1 and B7.2 ligands as nonchemical adjuvants, SPV vectors containing full-length feline B7.1 and B7.2 ligands were constructed and analyzed. Full-length feline B7.1 and B7.2 produced from SPV vectors were natively processed and costimulated Jurkat cells to produce IL-2, in vitro. In addition, we explored the feasibility of utilizing SPV as a novel expression vector to produce soluble forms of feline B7.1 (sB7.1) and B7.2 (sB7.2) in tissue culture. The transmembrane and cytoplasmic regions of the B7.1 and B7.2 genes were replaced with a poly-histidine tag and purified via a two-step chromatography procedure. Receptor binding and costimulation activity was measured. Although feline sB7.1-his and sB7.2-his proteins bound to the human homolog receptors, CTLA-4 and CD28, both soluble ligands possessed greater affinity for CTLA-4, compared to CD28. However, both retained the ability to partially block CD28-mediated costimulation in vitro. Results from these studies establish the use of SPV as a mammalian expression vector and suggest that full-length-vectored and purified soluble feline B7 ligands may be valuable, nonchemical immune-modulators.
- Published
- 2005
- Full Text
- View/download PDF
19. Comparison of the safety and efficacy of a recombinant feline leukemia virus (FeLV) vaccine delivered transdermally and an inactivated FeLV vaccine delivered subcutaneously.
- Author
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Grosenbaugh DA, Leard T, Pardo MC, Motes-Kreimeyer L, and Royston M
- Subjects
- Administration, Cutaneous, Animals, Antigens, Viral blood, Cats, Injections, Subcutaneous veterinary, Random Allocation, Safety, Specific Pathogen-Free Organisms, Treatment Outcome, Vaccines, Inactivated administration & dosage, Vaccines, Inactivated standards, Vaccines, Synthetic administration & dosage, Vaccines, Synthetic standards, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic administration & dosage, Retroviridae Proteins, Oncogenic standards, Vaccination veterinary, Viral Vaccines administration & dosage, Viral Vaccines standards
- Abstract
The efficacy of a new recombinant FeLV vaccine (rFeLV), delivered transdermally via a needle-free delivery device was compared to that of an inactivated FeLV vaccine (FeLV-k), administered subcutaneously, with a conventional needle and syringe. Kittens were immunized with either rFeLV (0.25 ml, transdermal) or FeLV-k (1 ml, subcutaneous); or they were sham-vaccinated with physiologic saline (0.25 ml, transdermal). Two vaccinations were administered 21 days apart. Injection sites were monitored for any acute or subacute reactions relative to vaccine administration. Four weeks following the final vaccination, all cats were subject to oro-nasal FeLV challenge. Blood was collected for determination of FeLV antigenemia (p27) at weekly intervals beginning three weeks post-challenge. All of the vaccinated cats from both groups resisted FeLV challenge; and 90% of the control cats developed persistent FeLV antigenemia in response to challenge. No acute or persistent injection site reactions were observed. The rFeLV, delivered transdermally, provides protection against persistent FeLV antigenemia following a robust challenge that is equivalent to that of FeLV-k.
- Published
- 2004
20. Efficacy of a canarypox virus-vectored vaccine against feline leukaemia.
- Author
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Poulet H, Brunet S, Boularand C, Guiot AL, Leroy V, Tartaglia J, Minke J, Audonnet JC, and Desmettre P
- Subjects
- Animals, Antibody Formation, Cats, Chick Embryo, Gene Expression Regulation, Leukemia, Feline immunology, Canarypox virus genetics, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccines, Synthetic immunology, Vaccines, Synthetic pharmacology
- 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.
- Published
- 2003
- Full Text
- View/download PDF
21. Feline leukaemia virus and vaccination.
- Author
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Sparkes AH
- Subjects
- Animals, Cats, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccination veterinary, Viral Vaccines
- Published
- 2003
- Full Text
- View/download PDF
22. Manufacturer addresses concerns about FIV vaccine.
- Author
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Connell S
- Subjects
- Animals, Cats, Leukemia Virus, Feline classification, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Leukemia, Feline virology, Polymerase Chain Reaction methods, Polymerase Chain Reaction veterinary, Leukemia Virus, Feline isolation & purification, Leukemia, Feline diagnosis, Retroviridae Proteins, Oncogenic, Viral Vaccines
- Published
- 2003
23. Implementation of a feral cat management program on a university campus.
- Author
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Hughes KL and Slater MR
- Subjects
- Animals, Euthanasia, Animal, Feline Acquired Immunodeficiency Syndrome prevention & control, Female, Leukemia, Feline prevention & control, Male, Population Control methods, Population Dynamics, Texas, Animal Welfare, Animals, Wild surgery, Castration veterinary, Cats surgery, Vaccination veterinary
- Abstract
In August 1998, Texas AM University implemented on campus a trap-test-vaccinate-alter-return-monitor (TTVARM) program to manage the feral cat population. TTVARM is an internationally recognized term for trapping and neutering programs aimed at management of feral cat populations. In this article we summarize results of the program for the period August 1998 to July 2000. In surgery laboratories, senior veterinary students examined cats that were humanely trapped once a month and tested them for feline leukemia and feline immunodeficiency virus infections, vaccinated, and surgically neutered them. They euthanized cats testing positive for either infectious disease. Volunteers provided food and observed the cats that were returned to their capture sites on campus and maintained in managed colonies. The program placed kittens and tame cats for adoption; cats totaled 158. Of the majority of 158 captured cats, there were less kittens caught in Year 2 than in Year 1. The proportion of tame cats trapped was significantly greater in Year 2 than in Year 1. The prevalence found for feline leukemia and feline immunodeficiency virus ELISA test positives was 5.8% and 6.5%, respectively. Following surgery, 101 cats returned to campus. The project recaptured, retested, and revaccinated more than one-fourth of the cats due for their annual vaccinations. The program placed 32 kittens, juveniles, and tame adults for adoption. The number of cat complaints received by the university's pest control service decreased from Year 1 to Year 2.
- Published
- 2002
- Full Text
- View/download PDF
24. Safety and efficacy of a recombinant FeLV vaccine combined with a live feline rhinotracheitis, calicivirus and panleukopenia vaccine.
- Author
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Gueguen S, Martin V, Bonnet L, Saunier D, Mähl P, and Aubert A
- Subjects
- Animals, Caliciviridae Infections prevention & control, Calicivirus, Feline immunology, Cats, Feline Panleukopenia immunology, Feline Panleukopenia Virus immunology, Female, Leukemia, Feline immunology, Male, Pneumovirus immunology, Pneumovirus Infections prevention & control, Vaccination adverse effects, Caliciviridae Infections veterinary, Feline Panleukopenia prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Pneumovirus Infections veterinary, Vaccination veterinary
- Published
- 2000
- Full Text
- View/download PDF
25. Vaccination against feline leukaemia using a new feline herpesvirus type 1 vector.
- Author
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Willemse MJ, van Schooneveld SH, Chalmers WS, and Sondermeijer PJ
- Subjects
- Administration, Intranasal, Animals, Cats, Gene Expression Regulation, Viral immunology, Genes, env immunology, Genetic Vectors administration & dosage, Genetic Vectors metabolism, Herpesviridae immunology, Leukemia Virus, Feline genetics, Leukemia, Feline immunology, Vaccines, Synthetic administration & dosage, Viral Vaccines administration & dosage, Viral Vaccines genetics, Genetic Vectors immunology, Herpesviridae genetics, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccines, Synthetic immunology, Viral Vaccines immunology
- Abstract
A recombinant feline herpesvirus type 1 (FHV-1) was constructed expressing the envelope glycoprotein gene from feline leukaemia virus (FeLV). The expression cassette containing the long terminal repeat promoter from Rous sarcoma virus was stably integrated at the locus downstream of the gC homologue in FHV-1. Oronasal vaccination with recombinant FHV-1 engendered significant protection against challenge with the homologous FelV-A/Glasgow-1 isolate. Three of four vaccinated cats did not become viraemic for FeLV and developed serum neutralizing antibodies while five of six controls became persistently infected after challenge. However, latent FeLV was detected at 12 weeks after challenge in bone marrow cultures of all animals except one. The potential of this new vector to protect against FeLV was compared with previous reports using live recombinant vaccines.
- Published
- 1996
- Full Text
- View/download PDF
26. Evaluation of feline leukemia virus control measures.
- Author
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Lubkin SR, Romatowski J, Zhu M, Kulesa PM, and White KA
- Subjects
- Animals, Cats, Disease Susceptibility, Evaluation Studies as Topic, Leukemia, Feline epidemiology, Models, Biological, Population Density, Prevalence, Social Environment, Immunization veterinary, Leukemia, Feline prevention & control
- Abstract
A susceptible-infected-recovered-susceptible (SIRS) model of the epidemiology of feline leukemia virus is formulated and analysed. The dynamics of the disease are dramatically different in no-risk, low-risk and high-risk subpopulations of asocial, free roaming, and multiple cat household cats. Among low risk (<1% prevalence) free roaming cats, the model predicts that an effective immunization rate of 4% year-1, or an effective removal rate of 8% year-1 are adequate to control the disease completely. Under higher risk (10% prevalence) conditions, an effective immunization rate of 23-72% year-1 or a removal rate of 69-145% year-1 are required for control. At very high (30%) prevalence rates, even heroic measures may not suffice to substantially reduce disease prevalence: a vaccination rate of 100% year-1 even if attainable, would only slightly reduce disease prevalence from 30% to 29%. We conclude that the current estimated effective feline leukemia virus immunization rate of 11-19% of the general population is inadequate to provide herd immunity in the subpopulation of cats which are genuinely at risk of infection. A substantial increase in the vaccination rate and/or intensification of test and removal efforts in the at risk population would be required to attain an effective level of protection.
- Published
- 1996
- Full Text
- View/download PDF
27. Comparative studies of the efficacy of a recombinant feline leukaemia virus vaccine.
- Author
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Jarrett O and Ganière JP
- Subjects
- Animals, Cats, Leukemia, Feline immunology, Phenotype, Time Factors, Vaccines, Inactivated immunology, Vaccines, Inactivated standards, Vaccines, Synthetic immunology, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccines, Synthetic standards
- Abstract
The efficacy of three feline leukaemia virus (FeLV) vaccines was compared. Kittens were immunised with either a recombinant subunit vaccine, Leucogen, or one of two inactivated virus vaccines, Leukocell 2 or Leucat. On subsequent challenge by intraperitoneal inoculation of FeLV of subgroup A (FeLV-A), only Leucogen gave significant protection. In a second experiment, kittens vaccinated with Leucogen were protected against oronasal challenge with a phenotypic mixture of FeLV of subgroups A, B and C. These results indicate that a recombinant vaccine, containing only the protein moiety of the surface glycoprotein of FeLV-A, can provide better protection than the inactivated virus vaccines tested against challenge with virus of the same subgroup, and can also protect against challenge by all three subgroups of FeLV.
- Published
- 1996
- Full Text
- View/download PDF
28. Development and testing of an inactivated feline leukemia virus vaccine.
- Author
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Hoover EA, Mullins JI, Chu HJ, and Wasmoen TL
- Subjects
- Animals, Cats, Cloning, Molecular, Vaccines, Inactivated administration & dosage, Vaccines, Inactivated biosynthesis, Vaccines, Inactivated immunology, Viral Vaccines administration & dosage, Viral Vaccines biosynthesis, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Viral Vaccines immunology
- Abstract
We assessed an inactivated whole virus feline leukemia virus (FeLV) vaccine developed from a molecularly cloned feline leukemia virus isolate (FeLV-61E-A) for its ability to protect cats against homologous and heterologous virulent virus challenge. The fractions of cats that resisted the induction of persistent viremia after FeLV challenge were the following: (1) FeLV-61E-A vaccine, 95%; (2) adjuvant controls, 26%; and (3) established commercial control FeLV vaccine, 35%. The pre-challenge mean neutralizing antibody titers for each group were (1) FeLV-61E-A vaccine, 1:43; (2) adjuvant controls, <1:8; and (3) established commercial control FeLV vaccine: 1:12. The commercial version of the prototype FeLV-61E-A vaccine (Fel-O-Vax, Fort Dodge Laboratories, Fort Dodge, IA) was developed through use of a proprietary adjuvant and a stable high antigen production cell lines. The efficacy and duration of immunity produced by Fel-O-Vax was studied alone and in multivalent combination with other feline virus vaccines in seven subsequent efficacy trials conducted in over 150 immunized cats. The overall FeLV-resistant fraction in these trials was 87% in vaccinated cats versus 8% in adjuvant controls. The duration of protective immunity induced by the multivalent Fel-O-Vax-LvK IV at 1 year postvaccination was 100% in challenged vaccinees versus 0% in challenged controls. The results of these studies show that an inactivated FeLV vaccine prepared from a molecularly cloned subgroup A FeLV can produce high level protective immunity against FeLV infection. This immunity is durable for at least 1 year without intervening booster immunization or virus exposure.
- Published
- 1995
29. Vaccination against feline leukaemia virus.
- Author
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Kerr MG
- Subjects
- Animals, Cats, Leukemia Virus, Feline immunology, Viral Vaccines administration & dosage, Leukemia, Feline prevention & control, Vaccination veterinary
- Published
- 1994
- Full Text
- View/download PDF
30. Diagnosis, therapy, and prevention of common infectious diseases in the cat.
- Author
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Greene CE
- Subjects
- Animals, Cats, Feline Acquired Immunodeficiency Syndrome prevention & control, Feline Infectious Peritonitis prevention & control, Feline Acquired Immunodeficiency Syndrome diagnosis, Feline Acquired Immunodeficiency Syndrome therapy, Feline Infectious Peritonitis diagnosis, Feline Infectious Peritonitis therapy, Leukemia, Feline diagnosis, Leukemia, Feline prevention & control, Leukemia, Feline therapy
- Published
- 1994
31. Evaluation of a feline leukemia virus vaccine in a controlled natural transmission study.
- Author
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Lafrado LJ
- Subjects
- Animals, Antigens, Viral blood, Cats, Enzyme-Linked Immunosorbent Assay, Female, Fluorescent Antibody Technique, Male, Retroviridae Infections prevention & control, Single-Blind Method, Specific Pathogen-Free Organisms, Tumor Virus Infections prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Infections veterinary, Retroviridae Proteins, Oncogenic, Tumor Virus Infections veterinary, Viral Vaccines
- Abstract
Twenty-six 8-week-old specific-pathogen-free cats were vaccinated subcutaneously with 2 doses of a commercially available FeLV vaccine, and 26 age-matched specific-pathogen-free cats were similarly vaccinated with a placebo vaccine containing the same adjuvant as the FeLV vaccine. Cats then were randomly assigned to 2 groups of 26 cats (13 FeLV-vaccinated cats and 13 control cats), and each group was housed with 5 cats previously inoculated with FeLV. All cats were tested biweekly for the next 26 weeks for evidence of FeLV antigenemia. Five of the 26 control cats developed antigenemia. However, 4 of these cats were only transiently antigenemic (positive results for 3 consecutive biweekly samples) and only 1 was persistently antigenemic. None of the FeLV-vaccinated cats developed antigenemia. Preventable fraction was calculated to be 100%.
- Published
- 1994
32. Vaccination against feline leukaemia virus.
- Author
-
Jarrett O
- Subjects
- Animals, Cats, Leukemia Virus, Feline immunology, Leukemia, Feline diagnosis, Prevalence, Viral Vaccines therapeutic use, Leukemia, Feline prevention & control, Vaccination veterinary
- Published
- 1994
- Full Text
- View/download PDF
33. [Vaccination of cats against infection with feline leukemia virus (FeLV): first recombinant vaccine and the effect of a pre-existing infection with feline immunodeficiency virus (FIV)].
- Author
-
Hofmann-Lehmann R, Aubert A, Wolfensberger C, Cronier J, and Lutz H
- Subjects
- Animals, Cats, Male, Specific Pathogen-Free Organisms, Vaccination veterinary, Feline Acquired Immunodeficiency Syndrome immunology, Immunodeficiency Virus, Feline immunology, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Vaccines, Synthetic, Viral Vaccines
- Abstract
A new recombinant FeLV vaccine was evaluated in 30 specified pathogen-free cats 10 months of age cats. The vaccine consisted of the non-glycosylated FeLV envelope protein p45, aluminium hydroxide and a saponin adjuvant. The cats (n = 18) were vaccinated twice intramuscularly, 3 weeks apart. All animals were challenged intraperitoneally with FeLV subgroup A, 18 weeks later. While 94% of the vaccinated cats showed no viraemia or were only transiently viraemic, 80% of the non-vaccinated animals became persistently viraemic within 2 to 3 weeks. In our hands the preventable fraction of the vaccine was 93%. In order to determine the effect of a pre-existing infection with feline immunodeficiency virus on the efficacy of vaccination, 50% of the cats were previously infected with FIV. The infected cats were protected to the same degree as the non-infected animals. With prolonged duration of FIV infection the probability increases, that the immune system of the cat will fail and clinical signs will appear. In order to observe a state of possible immunodeficiency, an accurate clinical examination of every cat prior to vaccination seems of major importance.
- Published
- 1994
34. FeLV vaccination.
- Author
-
Vivian JS
- Subjects
- Animals, Cats, Leukemia Virus, Feline immunology, Leukemia, Feline immunology, Viral Vaccines, Leukemia, Feline prevention & control, Vaccination veterinary
- Published
- 1993
- Full Text
- View/download PDF
35. Protection of cats against feline leukemia virus by vaccination with a canarypox virus recombinant, ALVAC-FL.
- Author
-
Tartaglia J, Jarrett O, Neil JC, Desmettre P, and Paoletti E
- Subjects
- Animals, Canaries microbiology, Cats, Fluorescent Antibody Technique, Gene Products, env immunology, Genes, env, Genes, gag, Genes, pol, Genetic Vectors, Leukemia Virus, Feline genetics, Leukemia Virus, Feline growth & development, Neutralization Tests, Vaccines, Attenuated immunology, Vero Cells, Antibodies, Viral biosynthesis, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Poxviridae genetics, Vaccines, Synthetic immunology
- Abstract
Two ALVAC (canarypox virus)-based recombinant viruses expressing the feline leukemia virus (FeLV) subgroup A env and gag genes were assessed for their protective efficacy in cats. Both recombinant viruses contained the entire gag gene. ALVAC-FL also expressed the entire envelope glycoprotein, while ALVAC-FL(dl IS) expressed an env-specific gene product deleted of the putative immunosuppressive region. Although only 50% of the cats vaccinated with ALVAC-FL(dl IS) were protected against persistent viremia after oronasal exposure to a homologous FeLV isolate, all cats administered ALVAC-FL resisted the challenge exposure. Significantly, protection was afforded in the absence of detectable FeLV-neutralizing antibodies. These results represent the first effective vaccination of cats against FeLV with a poxvirus-based recombinant vector and have implications that are relevant not only to FeLV vaccine development but also to developing vaccines against other retroviruses, including human immunodeficiency virus.
- Published
- 1993
- Full Text
- View/download PDF
36. Feline leukemia virus. Immunization and prevention.
- Author
-
Loar AS
- Subjects
- Animals, Antibodies, Viral biosynthesis, Cats, Leukemia, Feline immunology, Immunization veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines
- Abstract
Our understanding of the pathogenesis of FeLV infection is little changed from what was described by Hardy and his colleagues in the mid-1970s. The prevention of FeLV infection consists, first, of avoiding the agent and, second, of providing optimum immunologic resistance. In multi-cat environments, the former is achieved through test-and-removal methods perennially reviewed in the literature and by minimizing exposure to outdoor cats. The latter is possible by attempting to maintain a low-stress, pathogen-free household and by the use of appropriate, effective immunization programs. Simple immunologic concepts used for the development of vaccines against feline distemper and rabies have evolved to enable generation of products that can now protect against retroviruses. The use of more complex biologic methods, such as recombinant technology and the manipulation of antigen presentation, bears encouragement, so that perhaps one day the most destructive of feline infectious diseases may be checked.
- Published
- 1993
- Full Text
- View/download PDF
37. Immunogenicity and efficacy of a commercial feline leukemia virus vaccine.
- Author
-
Pedersen NC
- Subjects
- Animals, Cats, Enzyme-Linked Immunosorbent Assay veterinary, Methylprednisolone administration & dosage, Random Allocation, Specific Pathogen-Free Organisms, Viremia immunology, Antibodies, Viral biosynthesis, Leukemia Virus, Feline immunology, Leukemia, Feline immunology, Leukemia, Feline prevention & control, Viral Vaccines immunology
- Abstract
Twenty young adult specific pathogen-free cats were randomly divided into two groups of 10 animals each. One group was vaccinated with two doses of feline leukemia virus vaccine according to the manufacturer's recommendations. All 20 cats were challenge exposed oronasally (4 times over a 1-week period), beginning 3 weeks after immunization, with a virulent subgroup A strain of FeLV (CT600-FeLV). The severity of the FeLV infection was enhanced by treating the cats with methylprednisolone acetate at the time of the last FeLV exposure. Ten of 10 nonvaccinated cats became persistently viremic compared with 0/10 of the vaccinates. ELISA antibodies to whole FeLV were present at high concentrations after immunization in all of the vaccinated cats, and there was no observable anamnestic antibody response after challenge exposure. ELISA antibodies to whole FeLV appeared at low concentrations in the serum of nonvaccinated cats after infection but disappeared as the viremia became permanently established. Virus neutralizing antibodies were detected in 3/10 vaccinates and 0/10 nonvaccinates immediately before FeLV challenge exposure, and in 8/10 vaccinates and 1/10 nonvaccinates 5 weeks later. Although vaccination did not consistently evoke virus neutralizing antibodies, it appeared to immunologically prime cats for a virus-neutralizing antibody response after infection. Active FeLV infection was detected in bone marrow cells taken 14 weeks after infection from 10/10 nonvaccinates and 0/10 vaccinates. Latent FeLV infection was not detected in bone marrow cells from any of the vaccinated cats 14 weeks after challenge exposure.
- Published
- 1993
- Full Text
- View/download PDF
38. Feline leukemia virus: pathophysiology, prevention, and treatment.
- Author
-
Cotter SM
- Subjects
- Animals, Antiviral Agents therapeutic use, Cats, Immunization, Leukemia Virus, Feline genetics, Leukemia, Feline immunology, Leukemia, Feline prevention & control, Leukemia, Feline therapy, Leukemia Virus, Feline physiology, Leukemia, Feline physiopathology
- Published
- 1992
- Full Text
- View/download PDF
39. Evaluation of a killed, whole virion feline leukemia virus vaccine.
- Author
-
Tizard I and Bass EP
- Subjects
- Animals, Cats, Evaluation Studies as Topic, Specific Pathogen-Free Organisms, Vaccines, Inactivated, Viremia prevention & control, Virion immunology, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines, Viremia veterinary
- Published
- 1991
40. Antibody response of kittens after vaccination followed by exposure to feline leukemia virus-infected cats.
- Author
-
Hawks DM, Legendre AM, Rohrbach BW, Sebring R, Chavez L, Chu HJ, and Acree WM
- Subjects
- Animals, Antibodies, Viral blood, Blotting, Western, Bone Marrow microbiology, Cats, Leukemia Virus, Feline isolation & purification, Neutralization Tests, Random Allocation, Specific Pathogen-Free Organisms, Viremia microbiology, Viremia prevention & control, Viremia veterinary, Antibodies, Viral biosynthesis, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic immunology, Vaccination veterinary, Viral Vaccines immunology
- Abstract
Protein (western) blot analysis and virus-neutralization assay were used to evaluate the antibody response of specific-pathogen-free kittens to FeLV vaccination and followed by natural exposure. Several kittens had barely detectable reactions to specific FeLV antigens prior to vaccination or exposure. Correlation was not found between protection against persistent viremia and antibody response after vaccination as measured by western blot analysis or virus neutralization assay. A statistically significant (P less than 0.01) difference in the antibody response against p27 antigen after natural exposure to FeLV was observed between persistently viremic kittens and transiently viremic or aviremic kittens. Measurable (P less than 0.05) virus neutralizing antibody titer after FeLV exposure was found only in a small number of kittens that were protected against persistent viremia. Lack of association between humoral response and vaccination-induced protection against persistent FeLV infection suggests an important role for cell-mediated immunity in such protection.
- Published
- 1991
41. Evaluation of efficacy and safety of an inactivated virus vaccine against feline leukemia virus infection.
- Author
-
Hines DL, Cutting JA, Dietrich DL, and Walsh JA
- Subjects
- Animals, Cats, Evaluation Studies as Topic, Female, Immunization, Secondary veterinary, Male, Specific Pathogen-Free Organisms, Vaccines, Inactivated adverse effects, Viremia prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic adverse effects, Vaccination veterinary, Viral Vaccines adverse effects, Viremia veterinary
- Abstract
An inactivated virus vaccine was developed for prevention of FeLV infection in domestic cats. When given in 2 doses, 3 weeks apart, to cats that were greater than or equal to 9 weeks old at the time of first vaccination, the vaccine prevented persistent viremia from developing in 132 of 144 (92%) vaccinates after oronasal challenge exposure with virulent FeLV. In contrast, persistent viremia developed after oronasal challenge exposure with FeLV in 39 of 45 (87%) age-matched nonvaccinated control cats. Transient viremia, indicated by early detection of p27 by ELISA in serum of cats protected from persistent viremia at 12 weeks after challenge exposure, was found in 10 of 132 (8%) vaccinates. Cats that were aviremic 12 to 16 weeks after challenge exposure were examined for reactivation of latent FeLV infection; 4 weekly doses of methylprednisolone were administered, followed by in vitro culture of bone marrow cells. Latent infection was readily reactivated in 6 of 8 (75%) nonvaccinated control cats that had been transiently viremic after challenge exposure. However, latent infection was reactivated in only 5 of 48 (10%) protected vaccinates, and in none of 38 vaccinates in which transient viremia had not been detected. In a safety field trial, only 34 mild reactions of short duration were observed after administration of 2,379 doses of vaccine to cats of various ages, breeds, and vaccination history, for a 1.43% reaction rate. Results indicate that the aforementioned inactivated virus vaccine is safe and efficacious for the prevention of infection with FeLV.
- Published
- 1991
42. Comparative efficacy of three commercial feline leukemia virus vaccines against methylprednisolone acetate-augmented oronasal challenge exposure with virulent virus.
- Author
-
Pedersen NC and Johnson L
- Subjects
- Animals, Antigens, Viral blood, Cats, Enzyme-Linked Immunosorbent Assay, Female, Male, Random Allocation, Specific Pathogen-Free Organisms, Viremia prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines, Viremia veterinary
- Abstract
Three commercial FeLV vaccines, (A, B, and C) were purchased on the open market and administered to 8- to 20-week-old specific-pathogen-free kittens, according to manufacturers' instructions. A similar group of nonvaccinated kittens served as controls. All kittens were challenge-exposed oronasally with virulent FeLV 4 weeks after the final vaccination. Serum samples were monitored for FeLV-p27 antigenemia using an ELISA at 1- to 2-week intervals for at least 16 weeks after the last day of challenge exposure. Kittens that were either transiently (1 to 4 weeks) or never viremic during this period were counted as recovered, whereas kittens that became viremic and retained viremia for at least 10 weeks were counted as persistently viremic. The 3 vaccines were found to be 39% (vaccine C), 28% (vaccine B), and 17% (vaccine A) efficacious in preventing persistent viremia in immunized, compared with nonimmunized kittens.
- Published
- 1991
43. Development of a whole killed feline leukemia virus vaccine.
- Author
-
York SM and York CJ
- Subjects
- Animals, Antibodies, Viral blood, Antigens, Viral blood, Cats, Chromatography, Neutralization Tests, Retroviridae Proteins, Oncogenic immunology, Retroviridae Proteins, Oncogenic standards, Vaccines, Inactivated analysis, Vaccines, Inactivated immunology, Vaccines, Inactivated standards, Viral Vaccines immunology, Viral Vaccines standards, Viremia prevention & control, Viremia veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic analysis, Vaccination veterinary, Viral Vaccines analysis
- Abstract
A whole killed FeLV vaccine was developed. By use of a chromatography method of purification and concentration, the resulting vaccine has been shown to be significantly lower in bovine serum albumin and total protein contents than were the same ingredients in the starting materials. The virus was inactivated or killed as an essential part of the vaccine development process. Vaccination trials with the vaccine without use of adjuvants indicated appreciable virus-neutralizing serum titer (greater than or equal to 1:10) in 107 of 110 vaccinated cats. Of 43 cats vaccinated and subsequently challenge exposed with virulent FeLV, only 2 developed persistent virus antigenemia (longer than 1 month), whereas 14 of 22 nonvaccinated control cats developed persistent viremia. In field tests, 2,770 cats from 6 states were vaccinated and observed. Postvaccinal reactions were not observed.
- Published
- 1991
44. Panel report on the colloquium on feline leukemia virus/feline immunodeficiency virus: tests and vaccination.
- Subjects
- Animals, Cats, Feline Acquired Immunodeficiency Syndrome diagnosis, Lentivirus Infections diagnosis, Leukemia, Feline diagnosis, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines, Feline Acquired Immunodeficiency Syndrome prevention & control, Immunodeficiency Virus, Feline immunology, Lentivirus Infections veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control
- Published
- 1991
45. Comparison of the efficacy of three commercial feline leukemia virus vaccines in a natural challenge exposure.
- Author
-
Legendre AM, Hawks DM, Sebring R, Rohrbach B, Chavez L, Chu HJ, and Acree WM
- Subjects
- Animals, Bone Marrow microbiology, Cats, Double-Blind Method, Enzyme-Linked Immunosorbent Assay, Female, Fluorescent Antibody Technique, Leukemia Virus, Feline isolation & purification, Male, Random Allocation, Specific Pathogen-Free Organisms, Viremia prevention & control, Viremia veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines
- Abstract
Forty-seven kittens were exposed for 31 weeks to 12 FeLV-positive carrier cats. The carrier cats were infected with 2 laboratory strains of FeLV and at least 2 strains of street virus. Eleven nonvaccinated control kittens and 12 vaccinated kittens were allotted to 3 groups. After 31 weeks of exposure, the following kittens were persistently blood FeLV positive by ELISA and immunofluorescence antibody (IFA) testing: 7 of the 11 control kittens, 0 of 12 kittens inoculated with vaccine A, 5 of 12 kittens inoculated with vaccine B, and 6 of 12 kittens inoculated with vaccine C. Only the kittens inoculated with vaccine A were significantly (P less than 0.05) different from the control group. After 23 weeks of exposure, culture was done to identify FeLV in the bone marrow of the kittens. Feline leukemia virus was isolated from the bone marrow of 9 of 11 control kittens. Virus was isolated from the bone marrow of 5 of 12 kittens inoculated with vaccine A, 11 of 12 kittens inoculated with vaccine B, and 10 of 12 kittens inoculated with vaccine C. Of the 17 cats that had FeLV isolated only from culture of bone marrow (negative results of blood virus isolation, ELISA, and IFA testing), 13 eliminated the virus from the bone marrow by week 31 of exposure. After 31 weeks of exposure, FeLV was isolated from the bone marrow of 8 of 11 control kittens, 0 of 12 kittens inoculated with vaccine A, 7 of 12 kittens inoculated with vaccine B, and 7 of 12 kittens inoculated with vaccine C.
- Published
- 1991
46. Feline leukemia virus vaccine development.
- Author
-
Sebring RW, Chu HJ, Chavez LG, Sandblom DS, Hustead DR, Dale B, Wolf D, and Acree WM
- Subjects
- Adjuvants, Immunologic, Animals, Bone Marrow microbiology, Cats, Fluorescent Antibody Technique, Leukemia Virus, Feline isolation & purification, Vaccines, Inactivated, Vaccines, Synthetic, Viremia prevention & control, Viremia veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines
- Published
- 1991
47. Efficacy and safety field trials of a recombinant DNA vaccine against feline leukemia virus infection.
- Author
-
Clark N, Kushner NN, Barrett CB, Kensil CR, Salsbury D, and Cotter S
- Subjects
- Adjuvants, Immunologic, Aluminum Hydroxide immunology, Animals, Antibodies, Viral biosynthesis, Antibodies, Viral blood, Cats, Female, Immunization, Secondary adverse effects, Immunization, Secondary veterinary, Injections, Subcutaneous adverse effects, Injections, Subcutaneous veterinary, Male, Saponins immunology, Vaccination adverse effects, Vaccination veterinary, Vaccines, Synthetic administration & dosage, Vaccines, Synthetic adverse effects, Vaccines, Synthetic immunology, Viremia prevention & control, Viremia veterinary, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic administration & dosage, Retroviridae Proteins, Oncogenic adverse effects, Retroviridae Proteins, Oncogenic immunology, Viral Vaccines administration & dosage, Viral Vaccines adverse effects, Viral Vaccines immunology
- Abstract
A new recombinant gp70 vaccine was found to be safe and effective for prevention of infection by FeLV. The vaccine incorporates a unique purified saponin adjuvant with the recombinant antigen. Serious systemic reactions were not observed during the efficacy trial. Local reactions were transient and mild. More than 2,000 doses were administered to a cross section of household cats in a field safety trial. Only 1 cat had hypersensitivity reaction, which resolved. Among veterinarians who used the vaccine and the cat owners, the vaccine was judged satisfactory and safe. After rigorous intraperitoneal challenge exposure without use of immunosuppressants, 100% of the controls in the efficacy trial became infected, 70% of which remained persistently infected with FeLV. Among vaccinates, 45% were never viremic and 40% cleared transient infection within 12 weeks after challenge exposure. Of the 20 vaccinated cats, 3 were persistently infected. Overall, 85% of cats vaccinated with this recombinant DNA FeLV vaccine resisted persistent FeLV infection after stringent challenge exposure, which translates to preventable fraction of 78.6%.
- Published
- 1991
48. Development of a genetically engineered vaccine against feline leukemia virus infection.
- Author
-
Kensil CR, Barrett C, Kushner N, Beltz G, Storey J, Patel U, Recchia J, Aubert A, and Marciani D
- Subjects
- Adjuvants, Immunologic, Animals, Antibodies, Viral biosynthesis, Cats, Immunization, Secondary veterinary, Recombinant Proteins immunology, Specific Pathogen-Free Organisms, Vaccines, Synthetic immunology, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic immunology, Vaccination veterinary, Viral Envelope Proteins immunology, Viral Vaccines immunology
- Abstract
A genetically engineered subunit vaccine against FeLV infection was developed. The protective immunogen in the vaccine was a purified recombinant protein containing the entire amino acid sequence of FeLV subgroup A gp70 envelope protein. The optimal adjuvant was determined to be a highly purified saponin, QS-21, derived from Quillaja saponaria Molina. A vaccine formulation containing the recombinant protein, QS-21, and aluminum hydroxide was tested in specific-pathogen-free kittens and was shown to induce neutralizing antibodies as well as appreciable antibody responses to native gp70 by enzyme immunoassay and protein (western) immunoblot analysis and of whole virus preparations.
- Published
- 1991
49. Year two of follow-up evaluation of a randomized, blind field trial of a commercial feline leukemia virus vaccine.
- Author
-
Scarlett JM and Pollock RV
- Subjects
- Animals, Cats, Enzyme-Linked Immunosorbent Assay, Evaluation Studies as Topic, Fluorescent Antibody Technique, Follow-Up Studies, Immunization, Secondary veterinary, Leukemia, Feline mortality, Risk Factors, Viremia mortality, Viremia prevention & control, Leukemia Virus, Feline immunology, Leukemia, Feline prevention & control, Retroviridae Proteins, Oncogenic, Vaccination veterinary, Viral Vaccines, Viremia veterinary
- Abstract
A blind randomized field trial of a commercial FeLV vaccine was conducted. Cats on study were vaccinated with either a commercial FeLV vaccine or a placebo, then housed with FeLV-positive cats in a ratio of approximately 2 study cats to 1 infected cat (results of the first 12 months of the study have been reported). All surviving placebo-treated and FeLV-vaccinated cats were re-vaccinated 1 year after initial exposure to FeLV-infected cats. Exposure continued for an additional 12 months, and the viremia status of the cats was monitored by immunofluorescent antibody (IFA) and ELISA testing at 4-month intervals. During the second year of observation, 1 additional FeLV-vaccinated cat had positive results of 2 consecutive ELISA tests, but remained IFA negative. Classifying this cat as persistently viremic reduced the estimate of the preventable fraction, but did not alter the conclusions drawn earlier, viz, that vaccination appreciably reduces the number of cats that become persistently viremic after long-term natural exposure.
- Published
- 1991
50. Overview of feline leukemia virus research.
- Author
-
Jarrett O
- Subjects
- Animals, Cats, Feline Acquired Immunodeficiency Syndrome epidemiology, Feline Acquired Immunodeficiency Syndrome prevention & control, Leukemia, Feline epidemiology, Leukemia, Feline prevention & control, Feline Acquired Immunodeficiency Syndrome microbiology, Leukemia Virus, Feline immunology, Leukemia Virus, Feline isolation & purification, Leukemia Virus, Feline physiology, Leukemia, Feline microbiology
- Published
- 1991
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