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Bronzoni RVM, Fatima M, Montassier S, Pereira GT, Gama NMSQ, Sakai V, Montassier HJ. Detection of Infectious Bronchitis Virus and Specific Anti- Viral Antibodies Using a Concanavalin A–Sandwich–ELISA. Viral Immunol 2005; 18:569-78. [PMID: 16212536 DOI: 10.1089/vim.2005.18.569] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Concanavalin A-Sandwich ELISA (Con A-S-ELISA) was developed for the detection of infectious bronchitis virus (IBV) or chicken specific anti-viral antibodies. The antigen detection limit for the Con A-S-ELISA was 10(5,1) EID(50)/mL. Three homologous and four heterologous IBV strains were similarly detected. This assay was highly effective in detecting the virus after infected tissue homogenates were passed once in embryonated chicken eggs, showing a good agreement with virus isolation technique. The Con A-S-ELISA was also used to measure anti-IBV chicken antibodies and showed a high coefficient of correlation (r = 0.85) and an agreement of k = 0.80 with the commercially available Indirect-ELISA. The relative sensitivity and specificity between these two tests were, respectively, 92.86% and 95.65% with an accuracy of 93.39%. Thus, the Con A-S-ELISA proved to be able to detect alternatively homologous and heterologous IBV strains or specific chicken anti- IBV antibodies, using the Con A as capture reagent of this assay.
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Affiliation(s)
- Roberta V M Bronzoni
- Faculdade de Ciências Agrárias e Veterinárias, Departamento de Patologia Veterinária, Laboratório de Imunologia e Virologia, Universidade Estadual Paulista, Rodovia Prof. Paulo Donato Castellane, 14884-900 Jaboticabal, SP, Brazil
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2
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Rosati S, Profiti M, Lorenzetti R, Bandecchi P, Mannelli A, Ortoffi M, Tolari F, Ciabatti IM. Development of recombinant capsid antigen/transmembrane epitope fusion proteins for serological diagnosis of animal lentivirus infections. J Virol Methods 2004; 121:73-8. [PMID: 15350735 DOI: 10.1016/j.jviromet.2004.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 05/24/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022]
Abstract
Among animal lentiviruses, Feline immunodeficiency virus (FIV), Equine infectious anaemia virus (EIAV) and Small ruminant lentiviruses (SRLV) are important pathogens associated with a variety of clinical pictures including immunodeficiency, anaemia, arthritis, pneumonia. The detection of viral antibody response represents a practical diagnostic approach in all lentivirus infections since they remain detectable long life. Capsid antigen (CA) is the major viral core protein and specific antibodies against this antigen are usually first recognised in infected sheep, goat and horse, remaining detectable for long period. Transmembrane (TM) domain of envelope glycoprotein contains a well conserved motif known to form an immunodominant epitope in several lentiviruses. In this study a simple strategy was developed to express the entire CA and the TM epitope in a single fusion protein from equine, feline and small ruminant lentiviruses in prokaryotic system and evaluated the diagnostic utility of a purified preparation in an indirect ELISA for each of the three infections. Results demonstrate that, for FIV and SRLV infections, the combination of CA and TM fractions increases the sensitivity of diagnostic tests based only on CA. The corresponding CA/TM antigen from EIAV showed excellent agreement with Coggins test.
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Affiliation(s)
- S Rosati
- Dipartimento di Produzioni Animali, Epidemiologia ed Ecologia, Facoltà di Medicina Veterinaria, Università di Torino, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy.
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3
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Dunham SP, Flynn JN, Rigby MA, Macdonald J, Bruce J, Cannon C, Golder MC, Hanlon L, Harbour DA, Mackay NA, Spibey N, Jarrett O, Neil JC. Protection against feline immunodeficiency virus using replication defective proviral DNA vaccines with feline interleukin-12 and -18. Vaccine 2002; 20:1483-96. [PMID: 11858854 DOI: 10.1016/s0264-410x(01)00507-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A molecular clone of the Glasgow-8 isolate of FIV (FIVGL8) was rendered replication defective by an in-frame deletion in either reverse transcriptase (deltaRT) or integrase (deltaIN) genes for use as DNA vaccines. To test the ability of these multi-gene vaccines to protect against two feline immunodeficiency virus (FIV) isolates of differing virulence, cats were immunized using either DNA vaccine alone or co-administered with interleukin-12 (IL-12) and/or interleukin-18 (IL-18) cytokine DNA. Animals were challenged sequentially with FIV-Petaluma (FIVPET) an FIV isolate of relatively low virulence and subsequently with the more virulent FIVGL8. A proportion of vaccinates (5/18 deltaIN and 2/12 deltaRT) were protected against primary challenge with FIV(PET). Five of the vaccinated-protected cats were re-challenged with FIV(PET); four (all deltaIN) remained free of viraemia whilst all naive controls became viraemic. Following subsequent challenge with the more virulent FIVGL8 these four vaccinated-protected animals all became viraemic but showed lower proviral loads than naive cats. This study suggests that while our current DNA vaccines may not produce sterilizing immunity against more virulent isolates of FIV, they may nevertheless significantly reduce the impact of infection.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Viral/biosynthesis
- Base Sequence
- Cats
- DNA, Viral/genetics
- Defective Viruses/enzymology
- Defective Viruses/genetics
- Defective Viruses/immunology
- Feline Acquired Immunodeficiency Syndrome/immunology
- Feline Acquired Immunodeficiency Syndrome/prevention & control
- Genes, Viral
- Immunodeficiency Virus, Feline/enzymology
- Immunodeficiency Virus, Feline/genetics
- Immunodeficiency Virus, Feline/immunology
- Immunodeficiency Virus, Feline/pathogenicity
- Integrases/genetics
- Interleukin-12/administration & dosage
- Interleukin-18/administration & dosage
- Molecular Sequence Data
- Proviruses/isolation & purification
- RNA-Directed DNA Polymerase/genetics
- Sequence Deletion
- T-Lymphocytes, Cytotoxic/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/pharmacology
- Viral Vaccines/administration & dosage
- Viral Vaccines/pharmacology
- Virulence
- Virus Replication/genetics
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Affiliation(s)
- Stephen P Dunham
- Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK.
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4
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Leutenegger CM, Boretti FS, Mislin CN, Flynn JN, Schroff M, Habel A, Junghans C, Koenig-Merediz SA, Sigrist B, Aubert A, Pedersen NC, Wittig B, Lutz H. Immunization of cats against feline immunodeficiency virus (FIV) infection by using minimalistic immunogenic defined gene expression vector vaccines expressing FIV gp140 alone or with feline interleukin-12 (IL-12), IL-16, or a CpG motif. J Virol 2000; 74:10447-57. [PMID: 11044089 PMCID: PMC110919 DOI: 10.1128/jvi.74.22.10447-10457.2000] [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: 11/20/2022] Open
Abstract
Four groups of cats, each containing four animals, were immunized at 0, 3, and 6 weeks with minimalistic immunogenic defined gene expression vector (MIDGE) vaccines containing the gene(s) for feline immunodeficiency virus (FIV) gp140, FIV gp140 and feline interleukin-12 (IL-12), FIV gp140 and feline IL-16, or FIV gp140 and a CpG motif. MIDGEs were coated onto gold beads and injected intradermally with a gene gun. A fifth group of four cats were immunized in an identical manner but with blank gold beads. All cats were challenge exposed to virulent FIV 4 weeks following the final immunization, and the course of infection was monitored. The two groups of cats immunized with the FIV gp140 gene alone or with blank gold particles became highly viremic and seroconverted as early as 4 weeks after infection. In contrast, three of four cats immunized with FIV gp140 in combination with feline IL-12 failed to become viremic or seropositive, as has been shown elsewhere (F. S. Boretti, C. M. Leutenegger, C. Mislin, et al., AIDS 14:1749-1757, 2000). Here we show the effect of IL-12 when used as an adjuvant on the viral RNA and DNA load and on the cytokine profile. In addition, the two groups of cats immunized either with gp140 and IL-16 or with gp140 and the CpG had greatly reduced viremia. Protection correlated weakly with cytotoxic T-lymphocyte activity and increased cytokine transcription of IL-12, gamma interferon, and IL-10 by peripheral blood mononuclear cells in the postchallenge period. This study extends the data on IL-12 and provides new results on CpG motifs and IL-16 used as adjuvants in the FIV cat model.
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Affiliation(s)
- C M Leutenegger
- Clinical Laboratory, Department of Internal Veterinary Medicine, University of Zurich, 8057 Zurich, Switzerland.
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5
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Hosie MJ, Dunsford T, Klein D, Willett BJ, Cannon C, Osborne R, Macdonald J, Spibey N, Mackay N, Jarrett O, Neil JC. Vaccination with inactivated virus but not viral DNA reduces virus load following challenge with a heterologous and virulent isolate of feline immunodeficiency virus. J Virol 2000; 74:9403-11. [PMID: 11000209 PMCID: PMC112369 DOI: 10.1128/jvi.74.20.9403-9411.2000] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has been shown that cats can be protected against infection with the prototypic Petaluma strain of feline immunodeficiency virus (FIV(PET)) using vaccines based on either inactivated virus particles or replication-defective proviral DNA. However, the utility of such vaccines in the field is uncertain, given the absence of consistent protection against antigenically distinct strains and the concern that the Petaluma strain may be an unrepresentative, attenuated isolate. Since reduction of viral pathogenicity and dissemination may be useful outcomes of vaccination, even in the absence of complete protection, we tested whether either of these vaccine strategies ameliorates the early course of infection following challenge with heterologous and more virulent isolates. We now report that an inactivated virus vaccine, which generates high levels of virus neutralizing antibodies, confers reduced virus loads following challenge with two heterologous isolates, FIV(AM6) and FIV(GL8). This vaccine also prevented the marked early decline in CD4/CD8 ratio seen in FIV(GL8)-infected cats. In contrast, DNA vaccines based on either FIV(PET) or FIV(GL8), which induce cell-mediated responses but no detectable antiviral antibodies, protected a fraction of cats against infection with FIV(PET) but had no measurable effect on virus load when the infecting virus was FIV(GL8). These results indicate that the more virulent FIV(GL8) is intrinsically more resistant to vaccinal immunity than the FIV(PET) strain and that a broad spectrum of responses which includes virus neutralizing antibodies is a desirable goal for lentivirus vaccine development.
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Affiliation(s)
- M J Hosie
- Department of Veterinary Pathology, University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom.
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6
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Mazzetti P, Giannecchini S, Del Mauro D, Matteucci D, Portincasa P, Merico A, Chezzi C, Bendinelli M. AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: detailed analysis of the humoral immune response to a protective vaccine. J Virol 1999; 73:1-10. [PMID: 9847300 PMCID: PMC103801 DOI: 10.1128/jvi.73.1.1-10.1999] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The feline immunodeficiency virus (FIV) cat model is extensively used to investigate possible vaccination approaches against AIDS in humans. Although consistent levels of protection have been achieved with FIV, as with other model systems, by immunizing with whole inactivated virus or fixed infected cells, the mechanisms responsible for protection are elusive. In previous studies we showed that cats immunized with a vaccine consisting of fixed infected cells were protected or unprotected against cell-free or cell-associated FIV challenge depending on the time interval between completion of vaccination and challenge. In an attempt to define possible humoral immune correlates of protection, selected sera harvested at the times of challenge from such cats were examined for anti-FIV-antibody titers and properties by using binding and functional immunological assays. Binding assays included quantitative Western blotting, enzyme-linked tests for antibodies to FIV glycoproteins and immunodominant linear epitopes, and tests for measuring conformation dependence and avidity of anti-viral-envelope antibodies. Functional assays included virus neutralization performed with two different cell substrates, complement- and antibody-dependent virolysis, blocking of reverse transcriptase, and an assay that measured the ability of sera to prevent FIV growth in cocultures of infected and uninfected cells. Despite the wide spectrum of parameters investigated, no correlation between vaccine-induced protection and the humoral parameters measured was noted.
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Affiliation(s)
- P Mazzetti
- Department of Biomedicine and Retrovirus Center, University of Pisa, Pisa, Italy
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7
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Hosie MJ, Flynn JN, Rigby MA, Cannon C, Dunsford T, Mackay NA, Argyle D, Willett BJ, Miyazawa T, Onions DE, Jarrett O, Neil JC. DNA vaccination affords significant protection against feline immunodeficiency virus infection without inducing detectable antiviral antibodies. J Virol 1998; 72:7310-9. [PMID: 9696827 PMCID: PMC109955 DOI: 10.1128/jvi.72.9.7310-7319.1998] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
To test the potential of a multigene DNA vaccine against lentivirus infection, we generated a defective mutant provirus of feline immunodeficiency virus (FIV) with an in-frame deletion in pol (FIVDeltaRT). In a first experiment, FIVDeltaRT DNA was administered intramuscularly to 10 animals, half of which also received feline gamma interferon (IFN-gamma) DNA. The DNA was administered in four 100-microg doses at 0, 10, and 23 weeks. Immunization with FIVDeltaRT elicited cytotoxic T-cell (CTL) responses to FIV Gag and Env in the absence of a serological response. After challenge with homologous virus at week 26, all 10 of the control animals became seropositive and viremic but 4 of the 10 vaccinates remained seronegative and virus free. Furthermore, quantitative virus isolation and quantitative PCR analysis of viral DNA in peripheral blood mononuclear cells revealed significantly lower virus loads in the FIVDeltaRT vaccinates than in the controls. Immunization with FIVDeltaRT in conjunction with IFN-gamma gave the highest proportion of protected cats, with only two of five vaccinates showing evidence of infection following challenge. In a second experiment involving two groups (FIVDeltaRT plus IFN-gamma and IFN-gamma alone), the immunization schedule was reduced to 0, 4, and 8 weeks. Once again, CTL responses were seen prior to challenge in the absence of detectable antibodies. Two of five cats receiving the proviral DNA vaccine were protected against infection, with an overall reduction in virus load compared to the five infected controls. These findings demonstrate that DNA vaccination can elicit protection against lentivirus infection in the absence of a serological response and suggest the need to reconsider efficacy criteria for lentivirus vaccines.
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Affiliation(s)
- M J Hosie
- Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, Glasgow G61 1QH, United Kingdom.
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8
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Bertrand O, Cochet S, Cartron JP. Expanded bed chromatography for one-step purification of mannose binding lectin from tulip bulbs using mannose immobilized on DEAE Streamline. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00575-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Del Mauro D, Matteucci D, Giannecchini S, Maggi F, Pistello M, Bendinelli M. Autologous and heterologous neutralization analyses of primary feline immunodeficiency virus isolates. J Virol 1998; 72:2199-207. [PMID: 9499077 PMCID: PMC109516 DOI: 10.1128/jvi.72.3.2199-2207.1998] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Feline immunodeficiency virus (FIV) provides a model system with which the significance of neutralizing antibody (NA) in immunosuppressive lentivirus infections may be studied. To date, no detailed analysis of the neutralization properties of primary FIV isolates has been reported. In this study, we have conducted the first comprehensive study of the sensitivity to autologous and heterologous neutralization in a lymphoid cell-based assay of 15 primary FIV isolates and, for comparison, of one tissue culture-adapted strain. Primary isolates in general proved highly NA resistant, although there was considerable individual variation. Variation was also observed in the capacity of immune sera to neutralize heterologous FIV isolates. The ability of sera to neutralize isolates or for isolates to be neutralized by sera did not correlate with epidemiological and genetic relatedness or with the quasispecies complexity of the isolates. From the study of specific-pathogen-free cats experimentally infected with viral isolates associated with NA of different breadths, it appears that the development of FIV vaccines cannot rely on the existence of viral strains inherently capable of inducing especially broad NA responses.
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Affiliation(s)
- D Del Mauro
- Retrovirus Center and Virology Section, Department of Biomedicine, University of Pisa, Italy
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10
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Giannecchini S, Matteucci D, Bendinelli M. Effect of enzymatic deglycosylation on feline immunodeficiency virus sensitivity to antibody-mediated neutralization. AIDS Res Hum Retroviruses 1998; 14:199-204. [PMID: 9491909 DOI: 10.1089/aid.1998.14.199] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We have investigated the effect of deglycosylation with peptide-N-glycosidase F (PNGase F) on the sensitivity to inhibition by immune sera of two variants of the Petaluma strain of feline immunodeficiency virus (FIV-Pet), one sensitive to antibody-mediated neutralization because tissue culture adapted and the other, obtained by passaging the previous one in vivo, resistant to neutralization. The partial deglycosylation achieved did not appreciably affect FIV-Pet infectivity for T lymphoid cell cultures and did not increase the susceptibility to serum neutralization of the resistant variant but totally prevented neutralization of the sensitive variant. These finding suggest that the epitopes involved in neutralization of tissue culture-adapted FIV-Pet are effectively recognized by antibody only when the viral surface is properly glycosylated.
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Affiliation(s)
- S Giannecchini
- Retrovirus Center and Virology Section, Department of Biomedicine, University of Pisa, Italy
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11
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Sibille P, Strosberg AD. A FIV epitope defined by a phage peptide library screened with a monoclonal anti-FIV antibody. Immunol Lett 1997; 59:133-7. [PMID: 9419019 DOI: 10.1016/s0165-2478(97)00111-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Phage peptide libraries constitute powerful tools for the mapping of epitopes recognized by monoclonal antibodies. We report here the characterization of an antibody directed against a 20-residue peptide derived from the surface glycoprotein of the feline immunodeficiency virus. The isolation of the WRPDF consensus sequence from a phage display library defined the exact epitope recognized by the mAb. Compared with known immunogenic peptides of the FIV envelope, it corresponds to the most immunodominant peptide found in the whole molecule. Kinetic data describing the antibody-peptide interactions were obtained by surface plasmon resonance. The antibody binds the peptide with a KD in the nanomolar range.
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Affiliation(s)
- P Sibille
- Institut Cochin de Génétique Moléculaire, Unité d'Immunopharmacologie moléculaire et génétique des virus, CNRS UPR 415, Paris, France.
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12
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Flynn JN, Cannon CA, Neil JC, Jarrett O. Vaccination with a feline immunodeficiency virus multiepitopic peptide induces cell-mediated and humoral immune responses in cats, but does not confer protection. J Virol 1997; 71:7586-92. [PMID: 9311839 PMCID: PMC192106 DOI: 10.1128/jvi.71.10.7586-7592.1997] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cats were immunized with a 46-residue multiepitopic synthetic peptide of feline immunodeficiency virus (FIV) comprising immunodominant epitopes present in the third variable domain of the envelope glycoprotein, transmembrane glycoprotein (TM), and p24 Gag core protein, using Quil A as an adjuvant. All vaccinated cats developed a humoral response which recognized the synthetic peptide immunogen and the intact viral core and envelope proteins. A FIV Gag- and Env-specific effector cytotoxic T-lymphocyte response was also detected in the peripheral blood of vaccinated cats, which peaked at week 30. This response appeared to be major histocompatibility complex restricted. Epitope mapping studies revealed that both the cellular and humoral immune responses were directed principally to a peptide within the TM glycoprotein, CNQNQFFCK. However, vaccination did not confer protection when cats were challenged with the Petaluma isolate of FIV at week 35.
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MESH Headings
- Adjuvants, Immunologic
- Amino Acid Sequence
- Animals
- Antibodies, Viral/biosynthesis
- Antibodies, Viral/blood
- Antibody Formation
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Cats
- Epitopes
- Feline Acquired Immunodeficiency Syndrome/immunology
- Gene Products, env/chemistry
- Gene Products, env/immunology
- Gene Products, gag/chemistry
- Gene Products, gag/immunology
- Immunity, Cellular
- Immunodeficiency Virus, Feline/immunology
- Molecular Sequence Data
- Quillaja Saponins
- Saponins
- T-Lymphocytes, Cytotoxic/immunology
- Vaccines, Synthetic
- Viral Envelope Proteins/immunology
- Viral Vaccines
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Affiliation(s)
- J N Flynn
- Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom.
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13
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Pancino G, Sonigo P. Retention of viral infectivity after extensive mutation of the highly conserved immunodominant domain of the feline immunodeficiency virus envelope. J Virol 1997; 71:4339-46. [PMID: 9151822 PMCID: PMC191650 DOI: 10.1128/jvi.71.6.4339-4346.1997] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In lentiviruses, including human immunodeficiency virus and feline immunodeficiency virus (FIV), the principal immunodominant domain (PID) of the transmembrane glycoprotein elicits a strong humoral response in infected hosts. The PID is marked by the presence of two cysteines that delimit a sequence, composed of five to seven amino acids in different lentiviruses, which is highly conserved among isolates of the same lentiviral species. While the conservation of the sequence suggests the presence of functional constraints, the conservation of the immunodominance among divergent lentiviruses raises the hypothesis of a selective advantage for the infecting virus conferred by the host humoral response against this domain. We and others have previously shown that an appropriate structure of the PID is required for the production of a functional envelope. In the present work, we analyzed virological functions and immune reactivity of the envelope after random mutagenesis of the PID of FIV. We obtained nine mutant envelopes which were correctly processed and retained fusogenic ability. Mutation of the two C-terminal residues of the PID sequence between the cysteines in a molecular clone of FIV abolished infectivity. In contrast, three molecular clones containing extensive mutations in the four N-terminal amino acids were infectious. However, the mutations affected PID reactivity with sera from infected cats. Our results suggest that functional constraints, although existent, are not sufficient to account for PID sequence conservation. Such conservation may also result from positive selection by anti-PID antibodies which enhance infection.
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Affiliation(s)
- G Pancino
- Génétique des Virus et Immunopharmacologie Moléculaire (ICGM-CNRS UPR0415), Institut Cochin de Génétique Moléculaire, Paris, France.
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14
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Willett BJ, Flynn JN, Hosie MJ. FIV infection of the domestic cat: an animal model for AIDS. IMMUNOLOGY TODAY 1997; 18:182-9. [PMID: 9136455 DOI: 10.1016/s0167-5699(97)84665-8] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- B J Willett
- Dept of Veterinary Pathology, University of Glasgow Veterinary School, UK.
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15
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Rigby MA, Hosie MJ, Willett BJ, Mackay N, McDonald M, Cannon C, Dunsford T, Jarrett O, Neil JC. Comparative efficiency of feline immunodeficiency virus infection by DNA inoculation. AIDS Res Hum Retroviruses 1997; 13:405-12. [PMID: 9075482 DOI: 10.1089/aid.1997.13.405] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Direct inoculation of genetic material in DNA form is a novel approach to vaccination that has proved efficacious for a number of viral agents. We are interested in the potential of this approach for the delivery of vaccines based on attenuated or replication-defective retroviruses. Toward this goal, we tested the effect of intramuscular inoculation of a plasmid containing the entire genome of feline immunodeficiency virus (FIV-Petaluma, F14 clone). DNA delivery was compared with intramuscular or intraperitoneal inoculation of virus reconstituted from the same molecular clone. The outcome was monitored by serological analysis and quantitative virus load determination over a 31-week period. DNA inoculation was found to be a reliable means of infection, although seroconversion and the rise in PBMC virus load were delayed relative to intramuscular or intraperitoneal inoculation of virus. At 31 weeks, similar levels of proviral DNA were detected in central lymphoid tissue of all infected animals. In conclusion, DNA inoculation of proviral DNA will be of use as a novel method of cell-free virus challenge and may have further potential for the delivery of lentiviral vaccines.
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Affiliation(s)
- M A Rigby
- Department of Veterinary Pathology, University of Glasgow Veterinary School, UK
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16
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Hosie MJ, Flynn JN. Feline immunodeficiency virus vaccination: characterization of the immune correlates of protection. J Virol 1996; 70:7561-8. [PMID: 8892875 PMCID: PMC190824 DOI: 10.1128/jvi.70.11.7561-7568.1996] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Whole inactivated virus (WIV) vaccines derived from the FL4 cell line protect cats against challenge with feline immunodeficiency virus (FIV). To investigate the correlates of protective immunity induced by WIV, we established an immunization regimen which protected a proportion of the vaccinates against challenge. A strong correlation was observed between high virus neutralizing antibody titers and protection following challenge. To investigate further the immune mechanisms responsible for immunity, all of the vaccinates were rechallenged 35 weeks following the initial challenge. Results of virus isolation from peripheral blood mononuclear cells indicated that 9 of 10 vaccinates were protected from viremia following the second challenge, suggesting that vaccine-induced immunity to FIV persisted for at least 8 months. However, more stringent analysis for evidence of infection revealed that 5 of 10 vaccinates harbored virus in lymphoid tissues. Unlike the protection observed immediately following vaccination, which correlated positively with virus neutralizing antibody titer, the ability to resist a second challenge with FIV was more closely correlated with the induction of Env-specific cytotoxic T-cell activity. The results indicate that both virus-specific humoral immunity and cellular immunity play a role in the protection induced in cats by WIV immunization but their relative importance may be dependent on the interval between vaccination and exposure to virus.
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Affiliation(s)
- M J Hosie
- MRC Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow, Bearsden, United Kingdom.
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Key Recent Literature. Viral Immunol 1995. [DOI: 10.1089/vim.1995.8.199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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