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Efficacy of Antiviral Drugs against Feline Immunodeficiency Virus. Vet Sci 2015; 2:456-476. [PMID: 29061953 PMCID: PMC5644647 DOI: 10.3390/vetsci2040456] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/05/2015] [Accepted: 10/21/2015] [Indexed: 11/29/2022] Open
Abstract
Feline immunodeficiency virus (FIV) is one of the most common infectious agents affecting cats worldwide .FIV and human immunodeficiency virus (HIV) share many properties: both are lifelong persistent lentiviruses that are similar genetically and morphologically and both viruses propagate in T-lymphocytes, macrophages, and neural cells. Experimentally infected cats have measurable immune suppression, which sometimes progresses to an acquired immunodeficiency syndrome. A transient initial state of infection is followed by a long latent stage with low virus replication and absence of clinical signs. In the terminal stage, both viruses can cause severe immunosuppression. Thus, FIV infection in cats has become an important natural model for studying HIV infection in humans, especially for evaluation of antiviral compounds. Of particular importance for chemotherapeutic studies is the close similarity between the reverse transcriptase (RT) of FIV and HIV, which results in high in vitro susceptibility of FIV to many RT-targeted antiviral compounds used in the treatment of HIV-infected patients. Thus, the aim of this article is to provide an up-to-date review of studies on antiviral treatment of FIV, focusing on commercially available compounds for human or animal use.
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Hartmann K. Efficacy of antiviral chemotherapy for retrovirus-infected cats: What does the current literature tell us? J Feline Med Surg 2015; 17:925-39. [PMID: 26486979 PMCID: PMC10816252 DOI: 10.1177/1098612x15610676] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
GLOBAL IMPORTANCE The two feline retroviruses, feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), are global and widespread, but differ in their potential to cause disease. VIRAL INFECTION - FIV FIV, a lentivirus that shares many properties with human immunodeficiency virus (HIV), can cause an acquired immune deficiency syndrome, which predisposes cats to other infections, stomatitis, neurological disorders and tumours. Although secondary infections are common, specific opportunistic infections or acquired immunodeficiency virus-defining infections, such as those that occur with HIV, are not commonly reported in FIV-infected cats. In most naturally infected cats, FIV does not cause a severe clinical syndrome; with appropriate care, FIV-infected cats can live many years before succumbing to conditions unrelated to their FIV infection. Thus, overall survival time is not necessarily shorter than in uninfected cats, and quality of life is usually high over many years or lifelong. VIRAL INFECTION - FELV FeLV, an oncornavirus, is more pathogenic than FIV. Historically, it was considered to account for more disease-related deaths and clinical syndromes in cats than any other infectious agent. Recently, the prevalence and importance of FeLV have been decreasing, mainly because of testing and eradication programmes and the use of FeLV vaccines. Progressive FeLV infection can cause tumours, bone marrow suppression and immunosuppression, as well as neurological and other disorders, and leads to a decrease in life expectancy. However, with appropriate care, many FeLV-infected cats can also live several years with a good quality of life. PRACTICAL RELEVANCE A decision regarding treatment or euthanasia should never be based solely on the presence or absence of a retrovirus infection. Antiviral chemotherapy is of increasing interest in veterinary medicine, but is still not used commonly. EVIDENCE BASE This article reviews the current literature on antiviral chemotherapy in retrovirus-infected cats, focusing on drugs that are currently available on the market and, thus, could potentially be used in cats.
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Affiliation(s)
- Katrin Hartmann
- Medizinische Kleintierklinik, Ludwig-Maximilians-Universität München, Veterinärstrasse 13, 80539 Munich, Germany
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Improved health and survival of FIV-infected cats is associated with the presence of autoantibodies to the primary receptor, CD134. Proc Natl Acad Sci U S A 2009; 106:19980-5. [PMID: 19901342 DOI: 10.1073/pnas.0911307106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We analyzed antibody responses in sera from feline immunodeficiency virus (FIV)-infected and uninfected cats. A strong antiviral response to the viral surface glycoprotein (SU) was noted in both natural and experimental infections. In addition, 143 of 226 FIV-infected animals (63%) also expressed antibodies to the primary binding receptor, CD134, whereas cats infected with other feline RNA viruses, including calicivirus, coronavirus, herpesvirus, and feline leukemia virus, did not. Both affinity-purified anti-CD134 and anti-SU antibodies blocked FIV infection ex vivo. FACS analyses revealed that the anti-CD134 antibodies bound to a cryptic epitope on the receptor that was only exposed when SU bound to CD134. Anti-CD134 binding caused displacement of SU from the surface of the cell and inhibition of infection. The presence of antibodies to CD134 correlated with lower virus loads and a better overall health status in FIV(+) cats, whereas anti-SU antibodies were present independent of health status. The findings are consistent with a role for antireceptor antibodies in protection from virus spread and disease progression.
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Willett BJ, McMonagle EL, Logan N, Samman A, Hosie MJ. A single site for N-linked glycosylation in the envelope glycoprotein of feline immunodeficiency virus modulates the virus-receptor interaction. Retrovirology 2008; 5:77. [PMID: 18721458 PMCID: PMC2563026 DOI: 10.1186/1742-4690-5-77] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 08/22/2008] [Indexed: 11/10/2022] Open
Abstract
Feline immunodeficiency virus (FIV) targets helper T cells by attachment of the envelope glycoprotein (Env) to CD134, a subsequent interaction with CXCR4 then facilitating the process of viral entry. As the CXCR4 binding site is not exposed until CD134-binding has occurred then the virus is protected from neutralising antibodies targeting the CXCR4-binding site on Env. Prototypic FIV vaccines based on the FL4 strain of FIV contain a cell culture-adapted strain of FIV Petaluma, a CD134-independent strain of FIV that interacts directly with CXCR4. In addition to a characteristic increase in charge in the V3 loop homologue of FIVFL4, we identified two mutations in potential sites for N-linked glycosylation in the region of FIV Env analogous to the V1–V2 region of HIV and SIV Env, T271I and N342Y. When these mutations were introduced into the primary GL8 and CPG41 strains of FIV, the T271I mutation was found to alter the nature of the virus-CD134 interaction; primary viruses carrying the T271I mutation no longer required determinants in cysteine-rich domain (CRD) 2 of CD134 for viral entry. The T271I mutation did not confer CD134-independent infection upon GL8 or CPG41, nor did it increase the affinity of the CXCR4 interaction, suggesting that the principal effect was targeted at reducing the complexity of the Env-CD134 interaction.
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Affiliation(s)
- Brian J Willett
- Retrovirus Research Laboratory, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Bearsden Road, Glasgow, G61 1QH, UK.
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Pecon-Slattery J, McCracken CL, Troyer JL, VandeWoude S, Roelke M, Sondgeroth K, Winterbach C, Winterbach H, O'Brien SJ. Genomic organization, sequence divergence, and recombination of feline immunodeficiency virus from lions in the wild. BMC Genomics 2008; 9:66. [PMID: 18251995 PMCID: PMC2270836 DOI: 10.1186/1471-2164-9-66] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 02/05/2008] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Feline immunodeficiency virus (FIV) naturally infects multiple species of cat and is related to human immunodeficiency virus in humans. FIV infection causes AIDS-like disease and mortality in the domestic cat (Felis catus) and serves as a natural model for HIV infection in humans. In African lions (Panthera leo) and other exotic felid species, disease etiology introduced by FIV infection are less clear, but recent studies indicate that FIV causes moderate to severe CD4 depletion. RESULTS In this study, comparative genomic methods are used to evaluate the full proviral genome of two geographically distinct FIV subtypes isolated from free-ranging lions. Genome organization of FIVPle subtype B (9891 bp) from lions in the Serengeti National Park in Tanzania and FIVPle subtype E (9899 bp) isolated from lions in the Okavango Delta in Botswana, both resemble FIV genome sequence from puma, Pallas cat and domestic cat across 5' LTR, gag, pol, vif, orfA, env, rev and 3'LTR regions. Comparative analyses of available full-length FIV consisting of subtypes A, B and C from FIVFca, Pallas cat FIVOma and two puma FIVPco subtypes A and B recapitulate the species-specific monophyly of FIV marked by high levels of genetic diversity both within and between species. Across all FIVPle gene regions except env, lion subtypes B and E are monophyletic, and marginally more similar to Pallas cat FIVOma than to other FIV. Sequence analyses indicate the SU and TM regions of env vary substantially between subtypes, with FIVPle subtype E more related to domestic cat FIVFca than to FIVPle subtype B and FIVOma likely reflecting recombination between strains in the wild. CONCLUSION This study demonstrates the necessity of whole-genome analysis to complement population/gene-based studies, which are of limited utility in uncovering complex events such as recombination that may lead to functional differences in virulence and pathogenicity. These full-length lion lentiviruses are integral to the advancement of comparative genomics of human pathogens, as well as emerging disease in wild populations of endangered species.
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Affiliation(s)
- Jill Pecon-Slattery
- Laboratory of Genomic Diversity, National Cancer Institute-Frederick, Frederick MD 21702 USA
| | - Carrie L McCracken
- Laboratory of Genomic Diversity, Basic Research Program-SAIC Frederick – National Cancer Institute, Frederick, MD 21702 USA
| | - Jennifer L Troyer
- Laboratory of Genomic Diversity, Basic Research Program-SAIC Frederick – National Cancer Institute, Frederick, MD 21702 USA
| | - Sue VandeWoude
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins CO 80532 USA
| | - Melody Roelke
- Laboratory of Genomic Diversity, Basic Research Program-SAIC Frederick – National Cancer Institute, Frederick, MD 21702 USA
| | - Kerry Sondgeroth
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman WA 99164 USA
| | | | | | - Stephen J O'Brien
- Laboratory of Genomic Diversity, National Cancer Institute-Frederick, Frederick MD 21702 USA
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de Parseval A, Grant CK, Sastry KJ, Elder JH. Sequential CD134-CXCR4 interactions in feline immunodeficiency virus (FIV): soluble CD134 activates FIV Env for CXCR4-dependent entry and reveals a cryptic neutralization epitope. J Virol 2006; 80:3088-91. [PMID: 16501119 PMCID: PMC1395450 DOI: 10.1128/jvi.80.6.3088-3091.2006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recombinant soluble CD134 (sCD134) facilitated feline immunodeficiency virus (FIV) entry into CXCR4-positive, cell surface CD134-negative target cells. sCD134-activated entry was dose dependent and CXCR4 dependent. We used the sCD134 activation system to explore the neutralization by four anti-V3 monoclonal antibodies (MAbs). V3 MAbs weakly neutralized FIV infection using target cells expressing both CD134 and CXCR4 but potently inhibited sCD134-activated entry into target cells expressing CXCR4 alone. These findings provide direct evidence for a sequential interaction of FIV Env with CD134 and CXCR4 and reveal the presence of a cryptic epitope in V3 that is masked in the mature envelope oligomers.
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MESH Headings
- Amino Acid Sequence
- Animals
- Cats
- Epitopes/chemistry
- Epitopes/genetics
- Epitopes/immunology
- Gene Expression Regulation, Viral
- Gene Products, env/chemistry
- Gene Products, env/genetics
- Gene Products, env/metabolism
- Genes, env
- HIV Envelope Protein gp120/chemistry
- Immunodeficiency Virus, Feline/metabolism
- Immunodeficiency Virus, Feline/pathogenicity
- Molecular Sequence Data
- Neutralization Tests
- Peptide Fragments/chemistry
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Receptors, CXCR4/metabolism
- Receptors, OX40
- Receptors, Tumor Necrosis Factor/metabolism
- Solubility
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Affiliation(s)
- Aymeric de Parseval
- The Scripps Research Institute, Department of Molecular Biology, MB-14, 10550 N. Torrey Pines Rd., La Jolla, California 92037, USA.
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Smirnova N, Troyer JL, Schissler J, Terwee J, Poss M, VandeWoude S. Feline lentiviruses demonstrate differences in receptor repertoire and envelope structural elements. Virology 2005; 342:60-76. [PMID: 16120451 DOI: 10.1016/j.virol.2005.07.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 06/09/2005] [Accepted: 07/20/2005] [Indexed: 11/15/2022]
Abstract
Feline immunodeficiency virus (FIV) causes fatal disease in domestic cats via T cell depletion-mediated immunodeficiency. Pumas and lions are hosts for apparently apathogenic lentiviruses (PLV, LLV) distinct from FIV. We compared receptor use among these viruses by: (1) evaluating target cell susceptibility; (2) measuring viral replication following exposure to specific and non-specific receptor antagonists; and (3) comparing Env sequence and structural motifs. Most isolates of LLV and PLV productively infected domestic feline T cells, but differed from domestic cat FIV by infecting cells independent of CXCR4, demonstrating equivalent or enhanced replication following heparin exposure, and demonstrating substantial divergence in amino acid sequence and secondary structure in Env receptor binding domains. PLV infection was, however, inhibited by CD134/OX40 antibody. Thus, although PLV and LLV infection interfere with FIV superinfection, we conclude that LLV and PLV utilize novel, more promiscuous mechanisms for cell entry than FIV, underlying divergent tropism and biological properties of these viruses.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Cats
- Cell Line
- DNA, Viral/genetics
- Glycosylation
- Immunodeficiency Virus, Feline/genetics
- Immunodeficiency Virus, Feline/immunology
- Immunodeficiency Virus, Feline/pathogenicity
- Immunodeficiency Virus, Feline/physiology
- Lentiviruses, Feline/genetics
- Lentiviruses, Feline/immunology
- Lentiviruses, Feline/pathogenicity
- Lentiviruses, Feline/physiology
- Lions
- Molecular Sequence Data
- Puma
- Receptors, CXCR4/antagonists & inhibitors
- Receptors, CXCR4/physiology
- Receptors, OX40
- Receptors, Tumor Necrosis Factor/antagonists & inhibitors
- Receptors, Virus/antagonists & inhibitors
- Receptors, Virus/physiology
- Sequence Homology, Amino Acid
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
- Viral Envelope Proteins/chemistry
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/physiology
- Virulence
- Virus Replication
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Affiliation(s)
- Natalia Smirnova
- Department of Microbiology, Immunology, and Pathology, Colorado State University, 1619 Campus Delivery, Fort Collins, CO 80523-1619, USA
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de Parseval A, Ngo S, Sun P, Elder JH. Factors that increase the effective concentration of CXCR4 dictate feline immunodeficiency virus tropism and kinetics of replication. J Virol 2004; 78:9132-43. [PMID: 15308709 PMCID: PMC506950 DOI: 10.1128/jvi.78.17.9132-9143.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surface glycoprotein (gp95) of the feline immunodeficiency virus (FIV) binds in a strain-specific manner to several cell surface molecules, including CXCR4, heparan sulfate proteoglycans (HSPGs), DC-SIGN, and a 43-kDa cell surface receptor on T cells recently identified as CD134 by M. Shimojima et al. (Science 303:1192-1195, 2004). CXCR4 is the entry receptor in all known cases, and the other molecules act as binding receptors to help facilitate infection. In this report, we confirm and extend the findings regarding CD134 as a primary receptor for FIV. In addition, we show that temperature critically influences the binding properties of FIV gp95 to CXCR4 and HSPGs. The data show that gp95 of the field strain FIV-PPR bound to CXCR4 at 22 degrees C, whereas binding was not detected at 4 degrees C. In contrast, binding of the laboratory adapted FIV-34TF10 gp95 was observed at either 4 degrees C or 22 degrees C, albeit at increased levels at the higher temperature. The level of CXCR4 increased after the temperature was switched from 4 to 22 degrees C, whereas the level of HSPGs decreased, resulting in higher binding of gp95 from both strains to CXCR4 and lower binding of gp95 of FIV-34TF10 to HSPGs (FIV-PPR gp95 does not bind to these molecules). The findings also show that HSPGs facilitate the CXCR4-mediated infectivity of CrFK and G355-5 cells by FIV-34TF10. These two nonlymphoid cell lines express very low levels of CXCR4 and are permissive to FIV-34TF10 but not to productive infection by FIV-PPR. However, overexpression of human CXCR4 in CrFK or G-355-5 cells resulted in extensive cell fusion and infection by FIV-PPR. Taken together, these findings indicate that factors that increase the effective concentration of CXCR4 enhance FIV infectivity and may involve (i) temperature or ligand-induced conformational changes in CXCR4 that enhance SU binding, (ii) coreceptor interactions with gp95 that either alter gp95 conformation to enhance CXCR4 binding and/or raise the localized concentration of receptor or ligand, or (iii) direct increase in CXCR4 concentration via overexpression.
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Affiliation(s)
- Aymeric de Parseval
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
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9
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Willett BJ, Cannon CA, Hosie MJ. Expression of CXCR4 on feline peripheral blood mononuclear cells: effect of feline immunodeficiency virus infection. J Virol 2003; 77:709-12. [PMID: 12477874 PMCID: PMC140578 DOI: 10.1128/jvi.77.1.709-712.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CXCR4 expression on feline peripheral blood mononuclear cells (PBMC) was analyzed. While monocytes and B lymphocytes expressed CXCR4, no CXCR4 was detected on T lymphocytes, in stark contrast to the expression pattern on T lymphocytes from humans. In spite of the important role that CXCR4 plays in infection with feline immunodeficiency virus, expression on PBMC in vivo was unaffected by infection with either a primary or a cell culture-adapted virus strain.
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Affiliation(s)
- Brian J Willett
- Retrovirus Research Laboratory, Institute of Comparative Medicine, Department of Veterinary Pathology, University of Glasgow, United Kingdom.
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10
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Willett BJ, Cannon CA, Hosie MJ. Upregulation of surface feline CXCR4 expression following ectopic expression of CCR5: implications for studies of the cell tropism of feline immunodeficiency virus. J Virol 2002; 76:9242-52. [PMID: 12186908 PMCID: PMC136470 DOI: 10.1128/jvi.76.18.9242-9252.2002] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Feline CXCR4 and CCR5 were expressed in feline cells as fusion proteins with enhanced green fluorescent protein (EGFP). Expression of the EGFP fusion proteins was localized to the cell membrane, and surface expression of CXCR4 was confirmed by using a cross-species-reactive anti-CXCR4 monoclonal antibody. Ectopic expression of feline CCR5 enhanced expression of either endogenous feline CXCR4 or exogenous feline or human CXCR4 expressed from a retrovirus vector, indicating that experiments investigating the effect of CCR5 expression on feline immunodeficiency virus (FIV) infection must be interpreted with caution. Susceptibility to infection with cell culture-adapted strains of FIV or to syncytium formation following transfection with a eukaryotic vector expressing an env gene from a cell culture-adapted strain of virus correlated with expression of either human or feline CXCR4, whereas feline CCR5 had no effect. In contrast, neither CXCR4 nor CCR5 rendered cells permissive to either productive infection with primary strains of FIV or syncytium formation following transfection with primary env gene expression vectors. Screening a panel of Ghost cell lines expressing diverse human chemokine receptors confirmed that CXCR4 alone supported fusion mediated by the FIV Env from cell culture-adapted viruses. CXCR4 expression was upregulated in Ghost cells coexpressing CXCR4 and CCR5 or CXCR4, CCR5, and CCR3, and susceptibility to FIV infection could be correlated with the level of CXCR4 expression. The data suggest that beta-chemokine receptors may influence FIV infection by modulating the expression of CXCR4.
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Affiliation(s)
- Brian J Willett
- Retrovirus Research Laboratory, Institute of Comparative Medicine, University of Glasgow Veterinary School, Glasgow G61 1QH, United Kingdom.
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Hosie MJ, Willett BJ, Klein D, Dunsford TH, Cannon C, Shimojima M, Neil JC, Jarrett O. Evolution of replication efficiency following infection with a molecularly cloned feline immunodeficiency virus of low virulence. J Virol 2002; 76:6062-72. [PMID: 12021339 PMCID: PMC136200 DOI: 10.1128/jvi.76.12.6062-6072.2002] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The development of an effective vaccine against human immunodeficiency virus is considered to be the most practicable means of controlling the advancing global AIDS epidemic. Studies with the domestic cat have demonstrated that vaccinal immunity to infection can be induced against feline immunodeficiency virus (FIV); however, protection is largely restricted to laboratory strains of FIV and does not extend to primary strains of the virus. We compared the pathogenicity of two prototypic vaccine challenge strains of FIV derived from molecular clones; the laboratory strain PET(F14) and the primary strain GL8(414). PET(F14) established a low viral load and had no effect on CD4(+)- or CD8(+)-lymphocyte subsets. In contrast, GL8(414) established a high viral load and induced a significant reduction in the ratio of CD4(+) to CD8(+) lymphocytes by 15 weeks postinfection, suggesting that PET(F14) may be a low-virulence-challenge virus. However, during long-term monitoring of the PET(F14)-infected cats, we observed the emergence of variant viruses in two of three cats. Concomitant with the appearance of the variant viruses, designated 627(W135) and 628(W135,) we observed an expansion of CD8(+)-lymphocyte subpopulations expressing reduced CD8 beta-chain, a phenotype consistent with activation. The variant viruses both carried mutations that reduced the net charge of the V3 loop (K409Q and K409E), giving rise to a reduced ability of the Env proteins to both induce fusion and to establish productive infection in CXCR4-expressing cells. Further, following subsequent challenge of naïve cats with the mutant viruses, the viruses established higher viral loads and induced more marked alterations in CD8(+)-lymphocyte subpopulations than did the parent F14 strain of virus, suggesting that the E409K mutation in the PET(F14) strain contributes to the attenuation of the virus.
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Affiliation(s)
- Margaret J Hosie
- Department of Veterinary Pathology, University of Glasgow, Glasgow G61 1QH, United Kingdom.
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12
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Gavrilin MA, Mathes LE, Podell M. Methamphetamine enhances cell-associated feline immunodeficiency virus replication in astrocytes. J Neurovirol 2002; 8:240-9. [PMID: 12053278 DOI: 10.1080/13550280290049660] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Human immunodeficiency virus (HIV) infection among substance abusers is on the rise worldwide. Psychostimulants, and in particular methamphetamine (METH), have detrimental effects on the immune system as well as causing a progressive neurodegeneration, similar to HIV infection. Many Lentivirinae, including feline immunodeficiency virus (FIV), penetrate into the central nervous system early in the course of infection with astrocytes serving as a reservoir of chronic brain infection. We demonstrate that the FIV-Maryland isolate infects feline primary and cell line (G355-5)-cultured astrocytes only under cell-associated conditions. Infected astrocytes yielded a new astrocytotropic isolate, capable of cell-free infection (termed FIV-MD-A). This isolate contained four amino acid substitutions in the envelope polyprotein resulting in a change in net charge as compared to FIV-MD. Infection for both isolates was dependent upon a functional astrocyte CXCR4 receptor. Methamphetamine increased significantly FIV replication in feline astrocytes for cell-associated infection only, with no effect on peripheral blood mononuclear cells or astrocytes infected with FIV-MD-A. This viral replication was related to proviral copy number, suggesting the effect of METH is at the viral entry or integration into host genome levels, but not at the translational level. Thus, lentiviral infection of the brain in the presence of the psychostimulant METH may result in enhanced astrocyte viral replication, producing a more rapid and increased brain viral load.
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Affiliation(s)
- Mikhail A Gavrilin
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine The Ohio State University, Columbus 43230, USA
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13
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Abstract
To identify the early target cells and tissues in transmucosal feline immunodeficiency virus (FIV) infection, cats were exposed to a clade C FIV isolate via the oral-nasal or vaginal mucosa and multiple tissues were examined by virus isolation coculture (VI), DNA PCR, catalyzed tyramide signal-amplified in situ hybridization (TSA-ISH), and immunohistochemistry between days 1 and 12 postinoculation (p.i.). FIV RNA was detected in tonsil and oral or vaginal mucosa as early as 1 day p.i. by TSA-ISH and in retropharyngeal, tracheobronchial, or external iliac lymph nodes and sometimes in spleen or blood mononuclear cells by day 2, indicating that regional and distant spread of virus-infected cells occurred rapidly after mucosal exposure. By day 8, viral RNA, DNA, and culturable virus were uniformly detected in regional and distant tissues, connoting systemic infection. TSA-ISH proved more sensitive than DNA PCR in detecting early FIV-infected cells. In mucosal tissues, the earliest demonstrable FIV-bearing cells were either within or subjacent to the mucosal epithelium or were in germinal centers of regional lymph nodes. The FIV(+) cells were of either of two morphological types, large stellate or small round. Those FIV RNA(+) cells which could be colabeled for a phenotype marker, were labeled for either dendritic-cell-associated protein p55 or T-lymphocyte receptor antigen CD3. These studies indicate that FIV crosses mucous membranes within hours after exposure and rapidly traffics via dendritic and T cells to systemic lymphoid tissues, a pathway similar to that thought to occur in the initial phase of infection by the human and simian immunodeficiency viruses.
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Affiliation(s)
- Leslie A Obert
- Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA
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14
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Johnston JB, Power C. Feline immunodeficiency virus xenoinfection: the role of chemokine receptors and envelope diversity. J Virol 2002; 76:3626-36. [PMID: 11907202 PMCID: PMC136059 DOI: 10.1128/jvi.76.8.3626-3636.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The use of chemokine receptors as cell recognition signals is a property common to several lentiviruses, including feline, human, and simian immunodeficiency viruses. Previously, two feline immunodeficiency virus (FIV) isolates, V1CSF and Petaluma, were shown to use chemokine receptors in a strain-dependent manner to infect human peripheral blood mononuclear cells (PBMC) (J. Johnston and C. Power, J. Virol. 73:2491-2498, 1999). Since the sequences of these viruses differed primarily in regions of the FIV envelope gene implicated in receptor use and cell tropism, envelope chimeras of V1CSF and Petaluma were constructed to investigate the role of envelope diversity in the profiles of chemokine receptors used by FIV to infect primate cells. By use of a receptor-blocking assay, all viruses were found to infect human and macaque PBMC through a mechanism involving the CXCR4 receptor. However, infection by viruses encoding the V3-to-V5 region of the V1CSF surface unit was also inhibited by blockade of the CCR3 or CCR5 receptor. Similar results were obtained with GHOST cells, human osteosarcoma cells expressing specific combinations of chemokine receptors. CXCR4 was required for infection by all FIV strains, but viruses expressing the V3-to-V5 region of V1CSF required the concurrent presence of either CCR3 or CCR5. In contrast, CXCR4 alone was sufficient to allow infection of GHOST cells by FIV strains possessing the V3-to-V5 region of Petaluma. To assess the role of primate chemokine receptors in productive infection, Crandell feline kidney (CrFK) cells that expressed human CXCR4, CCR3, or CCR5 in addition to feline CXCR4 were generated. Sustained infection by viruses encoding the V3-to-V5 region of V1CSF was detected in CrFK cells expressing human CCR3 or CCR5 but not in cells expressing CXCR4 alone, while all CrFK cell lines were permissive to viruses encoding the V3-to-V5 region of Petaluma. These results indicate that FIV uses chemokine receptors to infect both human and nonhuman primate cells and that the profiles of these receptors are dependent on envelope sequence, and they provide insights into the mechanism by which xenoinfections may occur.
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Affiliation(s)
- J B Johnston
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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Johnston JB, Silva C, Power C. Envelope gene-mediated neurovirulence in feline immunodeficiency virus infection: induction of matrix metalloproteinases and neuronal injury. J Virol 2002; 76:2622-33. [PMID: 11861828 PMCID: PMC135953 DOI: 10.1128/jvi.76.6.2622-2633.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Accepted: 12/05/2001] [Indexed: 12/18/2022] Open
Abstract
The release of neurotoxins by activated brain macrophages or microglia is one mechanism proposed to contribute to the development of neurological disease following infection by lentiviruses, including feline immunodeficiency virus (FIV). Since molecular diversity in the lentiviral envelope gene influences the expression of host molecules implicated in neuronal injury, the role of the envelope sequence in FIV neuropathogenesis was investigated by using the neurovirulent FIV strain V1CSF, the nonneurovirulent strain Petaluma, and a chimera (FIVCh) containing the V1CSF envelope gene in a Petaluma background. All three viruses replicated in primary feline macrophages with equal efficiency, but conditioned medium from V1CSF- or FIVCh-infected cells was significantly more neurotoxic than medium from Petaluma-infected cultures (P < 0.001) and could be attenuated in a dose-dependent manner by treatment with either the matrix metalloproteinase (MMP) inhibitor prinomastat (PMT) or function-blocking antibodies to MMP-2. Although FIV sequences were detectable by PCR in brain tissue from neonatal cats infected with each of the viral strains, immunohistochemistry revealed increased astrogliosis and macrophage activation in the brains of V1CSF- and FIVCh-infected cats relative to the other groups, together with elevated markers of neuronal stress that included morphological changes and increased c-fos immunoreactivity. Similarly, MMP-2, but not MMP-9, mRNA and protein expression was increased in brain tissues of V1CSF- and FIVCh-infected cats relative to Petaluma-infected animals (P < 0.01). Infection with V1CSF or FIVCh was also associated with greater CD4(+) cell depletion (P < 0.001) and neurodevelopmental delays (P < 0.005), than in Petaluma-infected animals; these deficits improved following PMT therapy. These findings indicated that diversity in the envelope gene sequence influenced the neurovirulence exhibited by FIV both in vitro and in vivo, possibly through a mechanism involving the differential induction of MMP-2.
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Affiliation(s)
- J B Johnston
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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Pandya S, Klimatcheva E, Planelles V. Lentivirus and foamy virus vectors: novel gene therapy tools. Expert Opin Biol Ther 2001; 1:17-40. [PMID: 11727544 DOI: 10.1517/14712598.1.1.17] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The aim of gene therapy is to modify the genetic material of living cells to achieve therapeutic benefit. Gene therapy involves the insertion of a functional gene into a cell, to replace an absent or defective gene, or to fight an infectious agent or a tumour. At present, a wide variety of somatic tissues are being explored for the introduction of foreign genes with a view towards treatment. A prime requirement for successful gene therapy is the sustained expression of the therapeutic gene without any adverse effect on the recipient. A highly desirable vector would be generated at high titres, integrate into target cells (including non-dividing cells) and have little or no associated immune reactions. Lentiviruses have the ability to infect dividing and non-dividing cells and, therefore, constitute ideal candidates for development of vectors for gene therapy. This review presents a description of available lentiviral vectors, including vector design, applications to disease treatment and safety considerations. In addition, general aspects of the biology of lentiviruses with relevance to vector development will be discussed. Recent investigations have revealed that foamy viruses, another group of retroviruses, are also capable of infecting non-dividing cells. Thus, foamy virus vectors are actively being developed in parallel to lentivirus vectors. This review will also include various aspects of the biology of foamy viruses with relevance to vector development.
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Affiliation(s)
- S Pandya
- Departments of Medicine and Microbiology and Immunology, University of Rochester Cancer Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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