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Vignuzzi M, Stone JK, Andino R. Ribavirin and lethal mutagenesis of poliovirus: molecular mechanisms, resistance and biological implications. Virus Res 2005; 107:173-81. [PMID: 15649563 DOI: 10.1016/j.virusres.2004.11.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Positive strand RNA virus populations are a collection of similar but genetically different viruses. They exist as viral quasispecies due to the high mutation rates of the low fidelity viral RNA-dependent RNA polymerase (RdRp). It is thought that this genomic heterogeneity is advantageous to the population, allowing for adaptation to rapidly changing environments that present varying types and degrees of selective pressure. However, one consequence of this extensive diversity is the susceptibility to mutagens that further increase sequence variation. Since RNA viruses live at the edge of maximal variability, an increase in the mutation rate is likely to force the virus beyond the tolerable mutation frequency into 'error catastrophe'. One such mutagen, ribavirin, is an antiviral nucleoside analog that is mutagenic to several RNA viruses. Ribavirin is incorporated into the viral genome causing lethal mutagenesis and a subsequent decrease in the specific infectivity. Even so, passaging poliovirus in the presence of low to intermediate concentrations of the drug leads to the emergence of a viral population resistant to the effects of ribavirin. These viruses have a point mutation in the RdRp that increases the overall polymerase fidelity. Interestingly, as predicted by the quasispecies theory, ribavirin resistant viruses are less adaptable, as they are more susceptible to other non-mutagenic antiviral drugs and are highly attenuated in vivo. Here, we review the mechanism of action of ribavirin on poliovirus and other RNA viruses, the possibility for escape via increased fidelity of the viral polymerase, the consequences of this response on viral population dynamics, and the biological implications for the therapeutic use of mutagenic antiviral agents.
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Affiliation(s)
- Marco Vignuzzi
- Department of Microbiology and Immunology, University of California, Mission Bay, Genentech Hall, Box 2280, San Francisco CA 94143-2280, USA
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Brodie SJ, de la Concha-Bermejillo A, Snowder GD, DeMartini JC. Current concepts in the epizootiology, diagnosis, and economic importance of ovine progressive pneumonia in North America: A review. Small Rumin Res 1998. [DOI: 10.1016/s0921-4488(97)00019-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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3
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Abstract
Maedi-Visna and ovine progressive pneumonia are disease of sheep that are caused by ovine lentivirus and characterized by chronic inflammation of the lungs, mammary glands, joints, and central nervous system. Although tremendous progress in research has led to a better understanding of the pathogenesis of these diseases, many questions still remain. Much of the mystery is the result of the complexity of the ovine lentivirus genome and the intricate interactions of the virus with the host during replication. Discoveries in molecular virology are shedding light on these interactions and novel approaches to prevent and control lentivirus infections are being explored. There is hope that some of these approaches will eventually be used to eradicate these diseases.
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Tobin GJ, Ennis WH, Clanton DJ, Gonda MA. Inhibition of bovine immunodeficiency virus by anti-HIV-1 compounds in a cell culture-based assay. Antiviral Res 1996; 33:21-31. [PMID: 8955850 DOI: 10.1016/s0166-3542(96)00990-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The bovine immunodeficiency virus (BIV) and human immunodeficiency virus types 1 and 2 (HIV-1 and -2) are members of the lentivirus genus of retroviruses. Although DNA sequences of these viruses have diverged considerably, the BIV genome organization, function of structural and regulatory genes, and replication cycle are very similar to that of HIV-1, making BIV a potentially useful model to study compounds with anti-HIV-1 activity. A cell culture-based antiviral assay was developed to test compounds for inhibition of BIV replication. The assay uses an embryonic rabbit epithelial (EREp) cell line that is highly sensitive to BIV infection and cytopathology. The 50% effective concentrations (EC50) at which the virus was inhibited in EREp cells were determined for 13 nucleoside analog, non-nucleoside, tumor-suppressive, or membrane-surface inhibitory compounds. The nucleoside analogs (3'-azido-2',3'-dideoxythymidine, 2',3'-dideoxyinosine and 2',3'-dideoxycytosine), surface-membrane inhibitors (dextran sulfate, hypericin, Chicago Sky Blue and quinobene), the nucleoside reductase inhibitor (hydroxyurea), and a tumor-suppressive phorbol ester (prostratin) inhibited BIV with EC50 values similar to those derived in HIV-1 lymphocyte (CD4+)-based assays. BIV was markedly more resistant to inhibition with HIV-1-specific non-nucleoside reverse transcriptase inhibitors (NNRTIs) (thiazolobenzimidazole, oxathiin carboxanilide and thiocarbamate) than was HIV-1, which parallels results with NNRTIs in HIV-2 assays.
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Affiliation(s)
- G J Tobin
- Laboratory of Cell and Molecular Structure, SAIC Frederick, MD, USA.
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Thormar H, Balzarini J, Holy A, Jindrich J, Rosenberg I, Debyser Z, Desmyter J, De Clercq E. Inhibition of visna virus replication by 2',3'-dideoxynucleosides and acyclic nucleoside phosphonate analogs. Antimicrob Agents Chemother 1993; 37:2540-4. [PMID: 7509142 PMCID: PMC192732 DOI: 10.1128/aac.37.12.2540] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A series of acyclic nucleoside phosphonate (ANP) and 2',3'-dideoxynucleoside (ddN) derivatives were evaluated for their inhibitory effects on visna virus replication and maedi/visna virus-induced syncytium formation in sheep choroid plexus cells. Most ANP derivatives inhibited virus replication and syncytium formation within a concentration range of 0.2 to 1.8 microM. Among the most active ANP derivatives ranked (R)-9-(2-phosphonomethoxypropyl)adenine, (R)-9-(2-phosphonomethoxypropyl)-2,6-diaminopurine, and (S)-9-(3-fluoro-2-phosphonomethoxypropyl)adenine. Of the ddN derivatives, 2',3'-dideoxycytidine (ddCyd) proved to be the most inhibitory to visna virus-induced syncytium formation (50% effective concentration, 0.02 microM). The purine ddN analogs (i.e., 2',3'-dideoxyinosine, 2',3'-dideoxyadenosine, 2',3'-dideoxyguanosine, and 2,6-diaminopurine-2',3'-dideoxyribosine) were 10- to 30-fold less effective, and the thymidine derivatives 2',3'-didehydro-2',3'-dideoxythymidine (D4T) and 3'-azido-2',3'-dideoxythymidine (AZT) were more than 500-fold less inhibitory to visna virus than ddCyd. The 5'-triphosphate forms of AZT and D4T were 100- to 600-fold more inhibitory to visna virus particle-derived reverse transcriptase than was the 5'-triphosphate of ddCyd. The apparent discrepancy between the inhibitory effects of these ddN derivatives on virus replication and viral reverse transcriptase activity most likely reflects differences in the metabolic conversion of ddCyd versus D4T and AZT in sheep choroid plexus cells.
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Affiliation(s)
- H Thormar
- Institute of Biology, University of Iceland, Reykjavik
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6
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Rollinson EA. Prospects for Antiviral Chemotherapy in Veterinary Medicine: 2. Avian, Piscine, Canine, Porcine, Bovine and Equine Virus Diseases. Antivir Chem Chemother 1992. [DOI: 10.1177/095632029200300601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This paper, which is published in two parts, reviews the literature pertaining to antiviral chemotherapy of viruses of veterinary importance. While early reports in the 1970s referred to the chemotherapy of a number of different RNA and DNA viruses, there was considerable focus in the 1980s, initially on herpesviruses and latterly on retroviruses, and particularly in cats. Details are given of the successful treatments of FeLV and FIV, which have been used as animal models for HIV therapy. Therapy of equine, canine, bovine, porcine, avian, and fish diseases is also considered. The high costs of developing and registering a new chemical entity, especially for food species in which extensive toxicity/residue data are required, is the main reason why specific antiviral compounds are not currently available for veterinary use, although some non-specific immune modulators are now emerging. Concurrent availability of appropriate diagnostic tools is a prerequisite for successful veterinary antiviral chemotherapy, as is a greater understanding of the pathogenesis of virus infections in animals and the development of more sophisticated means of drug delivery, appropriate to both food animal species and companion animals (dogs, cats, and horses). Additionally, antiviral agents are valuable as research tools per se, as opposed to solely as chemotherapeutic agents. Part 1 covers the feline virus diseases, while part 2 includes the other viruses of veterinary importance, in dogs, horses, cattle, pigs, birds, and fish.
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Affiliation(s)
- E. A. Rollinson
- Pitman Moore Europe, Breakspear Road South, Harefield, Oxbridge UB9 6LS, UK
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7
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Rollinson EA. Prospects for Antiviral Chemotherapy in Veterinary Medicine: 1. Feline Virus Diseases. Antivir Chem Chemother 1992. [DOI: 10.1177/095632029200300501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This paper, which is published in two parts, reviews the literature pertaining to antiviral chemotherapy of viruses of veterinary importance. While early reports in the 1970s referred to the chemotherapy of a number of different RNA and DNA viruses, there was considerable focus in the 1980s, initially on herpesviruses and latterly on retroviruses, particularly in cats. Details are given of the successful treatments of FeLV and FIV, which have been used as animal models for HIV therapy. The high costs of developing and registering a new chemical entity, especially for food species, in which extensive toxicity/residue data are required, is the main reason why specific antiviral compounds are not currently available for veterinary use, although some non-specific immune modulators are now emerging. Concurrent availability of appropriate diagnostic tools is a prerequisite for successful veterinary antiviral chemotherapy, as is a greater understanding of the pathogenesis of virus infections in animals and the development of more sophisticated means of drug delivery, appropriate to both food animal species and companion animals. Additionally, antiviral agents are valuable as research tools per se, as opposed to solely as chemotherapeutic agents.
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Pétursson G, Andrésdóttir V, Andrésson O, Torsteinsdóttir S, Georgsson G, Pálsson PA. Human and ovine lentiviral infections compared. Comp Immunol Microbiol Infect Dis 1991; 14:277-87. [PMID: 1684142 DOI: 10.1016/0147-9571(91)90133-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Maedi-visna virus (MVV) of sheep was the first lentivirus to be isolated. The genomic organization of MVV is very similar to that of human immunodeficiency virus (HIV) with several genes regulating the expression of the viral genome. Viral replication is severely restricted in the host and some cells apparently contain the genetic information in a DNA provirus form with little or no expression of viral antigens. This seems to be a major factor in causing the "slowness" of lentiviral infections and the persistence of the virus in the host since the immune system may not recognize the provirus-containing cells. The target cells for HIV and MVV are similar although T4 lymphocytes are not specifically destroyed in maedi-visna. There are also certain similarities in the pathological changes in both diseases, both in the central nervous system, the lungs and the lymphatic system. Although the severe final immunodeficiency state characteristic of AIDS has not been observed in maedi-visna, the basic biological features of the MVV and its interaction with host cells are so similar to HIV infection, that we consider ovine maedi-visna useful animal model for the human lentivirus infections.
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Affiliation(s)
- G Pétursson
- Institute for Experimental Pathology, University of Iceland, Reykjavík
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Hoover EA, Zeidner NS, Mullins JI. Therapy of presymptomatic FeLV-induced immunodeficiency syndrome with AZT in combination with alpha interferon. Ann N Y Acad Sci 1990; 616:258-69. [PMID: 1964030 DOI: 10.1111/j.1749-6632.1990.tb17846.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
AZT inhibited replication of an immunodeficiency-inducing strain of feline leukemia virus (FeLV-FAIDS) in vitro at concentrations as low as 0.005 microgram/mL. This antiviral activity was augmented an additional 25-30% when AZT was combined with human recombinant alpha-interferon (2b) (IFN alpha). Administration of AZT alone or in combination with IFN alpha, beginning at the time of exposure to a 100% persistent viremia-inducing dose of FeLV-FAIDS, abrogated the progression of viral infection and protected treated animals from induction of persistent antigenemia and disease. Low levels of antigenemia were detected intermittently in some AZT-treated cats throughout the 6 week treatment and 40 week observation period. Combination of AZT with IFN alpha appeared even more effective than AZT alone. In this treatment group even transient antigenemia was undetectable throughout the therapy and posttherapy observation periods, and latent virus could not be reactivated from bone marrow cells of protected animals. These results provide additional evidence that early treatment with AZT or AZT/IFN alpha therapy can be effective in completely aborting retroviral infections.
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Affiliation(s)
- E A Hoover
- Department of Pathology, Colorado State University, Fort Collins 80523
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Abstract
Traditionally animal models have formed a vital part of the preclinical evaluation of new forms of antiviral therapy. A variety of models used in the past or potentially useful in the future are considered in this short review. Several valuable and complex questions concerning virus-drug interactions in vivo have been successfully addressed by means of animal models. Better understanding of drug modes of action and virus pathogenesis in the models enable even more accurate predictions to be made for the outcome of antiviral therapy in man. The complexity of virus infections in man is such that animals are likely to remain an important part in drug evaluation for many years. To this end, new developments such as improved techniques in the production of transgenic animals are opening up a variety of completely novel methods for studying inhibitors of a wider group of viruses in vivo including the human immunodeficiency virus. However, the correct interpretation of animal data requires the critical evaluation of animal models. This review will identify several important difficulties which confront those working on antiviral chemotherapy in animals and which must continue to be addressed if confidence in animal data is to be maintained.
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Affiliation(s)
- H J Field
- Department of Clinical Veterinary Medicine, University of Cambridge, U.K
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Bapat AR, Bodner AJ, Ting RC, Cheng YC. Identification and some properties of a unique DNA polymerase from cells infected with human B-lymphotropic virus. J Virol 1989; 63:1400-3. [PMID: 2783739 PMCID: PMC247839 DOI: 10.1128/jvi.63.3.1400-1403.1989] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
A new DNA polymerase and DNase activity were identified from cells infected with human B-lymphotropic herpesvirus (HBLV). DNA polymerase associated with HBLV infection was similar in its sensitivity to inhibition by ppi analogs as other herpesvirus-specific DNA polymerases but was dissimilar in its inhibition by certain nucleoside triphosphates.
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Affiliation(s)
- A R Bapat
- Department of Pharmacology, University of North Carolina, Chapel Hill 27599-7365
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Smee DF, McKernan PA, Alaghamandan HA, Frank KB, Ramasamy K, Revankar GR, Robins RK. Antiviral activities of 2'-deoxyribofuranosyl and arabinofuranosyl analogs of sangivamycin against retro- and DNA viruses. Antiviral Res 1988; 10:263-77. [PMID: 2854957 DOI: 10.1016/0166-3542(88)90045-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Eight sugar-modified pyrrolopyrimidine nucleoside analogs related to the antibiotic sangivamycin were evaluated in cell culture against herpes simplex types 1 (HSV-1) and 2 (HSV-2), cytomegalovirus (CMV), adenovirus, and visna virus. Five of the compounds were highly active against most of the viruses with 50% inhibition (ED50) values of 1-10 microM. The selectivity of the agents was low, with inhibition of uninfected cell proliferation occurring within 5-fold that of the virus ED50 for most of the viruses. The compounds did not possess RNA virus-inhibitory activity when evaluated against certain myxo-, paramyxo-, picorna-, reo-, rhabdo-, and togaviruses. Two of the nucleosides were tested further in a cell line persistently infected with Friend leukemia virus where they were inhibitory to both virus yield and cell proliferation at 4-5 microM. Several of the sangivamycin analogs were tested in animal models using a twice-a-day treatment regimen. They proved to be inactive against HSV-1, murine CMV and/or Friend leukemia virus infections in mice.
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Affiliation(s)
- D F Smee
- Nucleic Acid Research Institute, Costa Mesa, California 92626
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Affiliation(s)
- M Dawson
- Central Veterinary Laboratory, Weybridge, Surrey, U.K
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