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Earl PL, Americo JL, Moss B. Genetic studies of the susceptibility of classical and wild-derived inbred mouse strains to monkeypox virus. Virology 2015; 481:161-5. [PMID: 25791934 PMCID: PMC4437815 DOI: 10.1016/j.virol.2015.02.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 02/18/2015] [Accepted: 02/21/2015] [Indexed: 11/24/2022]
Abstract
Previously, we screened 38 inbred mouse strains for susceptibility to monkeypox virus (MPXV) and focused on wild-derived CAST mice because of their extreme vulnerability. Here, we provide further analysis of inbred mouse strains. NZW/Lac and C58 mice exhibited more weight loss than other classical inbred strains but all survived intranasal challenges with 10(4) to 10(6)PFU of MPXV. Mice from three wild derived strains, in addition to CAST, exhibited severe weight loss and died or were euthanized. LD50 values for CASA, MOLF and PERA were 100, 6800 and >10(5)PFU, respectively. CASA was inbred independently from the same founders as CAST, whereas MOLF and PERA are genetically and geographically distinct. The MPXV susceptibility of the F1 progeny of CAST and either C57BL/6 or BALB/c indicated that resistance is dominant. Back-crossing the F1 progeny of C57BL/6 and CAST to CAST suggested more than one independent resistant locus.
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Affiliation(s)
- Patricia L Earl
- Laboratory of Viral Diseases, 33 North Drive, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, Unites States
| | - Jeffrey L Americo
- Laboratory of Viral Diseases, 33 North Drive, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, Unites States
| | - Bernard Moss
- Laboratory of Viral Diseases, 33 North Drive, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, Unites States.
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Titova KA, Sergeev AA, Zamedyanskaya AS, Galahova DO, Kabanov AS, Morozova AA, Bulychev LE, Sergeev AA, Glotova TI, Shishkina LN, Taranov OS, Omigov VV, Zavjalov EL, Agafonov AP, Sergeev AN. Using ICR and SCID mice as animal models for smallpox to assess antiviral drug efficacy. J Gen Virol 2015; 96:2832-2843. [PMID: 26067292 DOI: 10.1099/vir.0.000216] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The possibility of using immunocompetent ICR mice and immunodeficient SCID mice as model animals for smallpox to assess antiviral drug efficacy was investigated. Clinical signs of the disease did not appear following intranasal (i.n.) challenge of mice with strain Ind-3a of variola virus (VARV), even when using the highest possible dose of the virus (5.2 log10 p.f.u.). The 50 % infective doses (ID50) of VARV, estimated by the virus presence or absence in the lungs 3 and 4 days post-infection, were 2.7 ± 0.4 log10 p.f.u. for ICR mice and 3.5 ± 0.7 log10 p.f.u. for SCID mice. After i.n. challenge of ICR and SCID mice with VARV 30 and 50 ID50, respectively, steady reproduction of the virus occurred only in the respiratory tract (lungs and nose). Pathological inflammatory destructive changes were revealed in the respiratory tract and the primary target cells for VARV (macrophages and epithelial cells) in mice, similar to those in humans and cynomolgus macaques. The use of mice to assess antiviral efficacies of NIOCH-14 and ST-246 demonstrated the compliance of results with those described in scientific literature, which opens up the prospect of their use as an animal model for smallpox to develop anti-smallpox drugs intended for humans.
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Affiliation(s)
- Ksenya A Titova
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Alexander A Sergeev
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Alena S Zamedyanskaya
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Darya O Galahova
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Alexey S Kabanov
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Anastasia A Morozova
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Leonid E Bulychev
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Artemiy A Sergeev
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Tanyana I Glotova
- State Scientific Establishment - Institute of Experimental Veterinary Science of Siberia and the Far East Russian Academy of Agricultural Sciences, Krasnoobsk, Novosibirsk Region, Russian Federation
| | - Larisa N Shishkina
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Oleg S Taranov
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Vladimir V Omigov
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Evgenii L Zavjalov
- Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Prospekt Lavrentyeva 10, 630090 Novosibirsk, Russian Federation
| | - Alexander P Agafonov
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
| | - Alexander N Sergeev
- Federal Budgetary Research Institution - State Research Center of Virology and Biotechnology VECTOR, Federal Service for Surveillance on Consumer Rights Protection and Human Well-being, Koltsovo, Novosibirsk region, Russian Federation
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Franceschi V, Parker S, Jacca S, Crump RW, Doronin K, Hembrador E, Pompilio D, Tebaldi G, Estep RD, Wong SW, Buller MR, Donofrio G. BoHV-4-Based Vector Single Heterologous Antigen Delivery Protects STAT1(-/-) Mice from Monkeypoxvirus Lethal Challenge. PLoS Negl Trop Dis 2015; 9:e0003850. [PMID: 26086739 PMCID: PMC4473039 DOI: 10.1371/journal.pntd.0003850] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 05/27/2015] [Indexed: 01/13/2023] Open
Abstract
Monkeypox virus (MPXV) is the etiological agent of human (MPX). It is an emerging orthopoxvirus zoonosis in the tropical rain forest of Africa and is endemic in the Congo-basin and sporadic in West Africa; it remains a tropical neglected disease of persons in impoverished rural areas. Interaction of the human population with wildlife increases human infection with MPX virus (MPXV), and infection from human to human is possible. Smallpox vaccination provides good cross-protection against MPX; however, the vaccination campaign ended in Africa in 1980, meaning that a large proportion of the population is currently unprotected against MPXV infection. Disease control hinges on deterring zoonotic exposure to the virus and, barring that, interrupting person-to-person spread. However, there are no FDA-approved therapies against MPX, and current vaccines are limited due to safety concerns. For this reason, new studies on pathogenesis, prophylaxis and therapeutics are still of great interest, not only for the scientific community but also for the governments concerned that MPXV could be used as a bioterror agent. In the present study, a new vaccination strategy approach based on three recombinant bovine herpesvirus 4 (BoHV-4) vectors, each expressing different MPXV glycoproteins, A29L, M1R and B6R were investigated in terms of protection from a lethal MPXV challenge in STAT1 knockout mice. BoHV-4-A-CMV-A29LgD106ΔTK, BoHV-4-A-EF1α-M1RgD106ΔTK and BoHV-4-A-EF1α-B6RgD106ΔTK were successfully constructed by recombineering, and their capacity to express their transgene was demonstrated. A small challenge study was performed, and all three recombinant BoHV-4 appeared safe (no weight-loss or obvious adverse events) following intraperitoneal administration. Further, BoHV-4-A-EF1α-M1RgD106ΔTK alone or in combination with BoHV-4-A-CMV-A29LgD106ΔTK and BoHV-4-A-EF1α-B6RgD106ΔTK, was shown to be able to protect, 100% alone and 80% in combination, STAT1(-/-) mice against mortality and morbidity. This work demonstrated the efficacy of BoHV-4 based vectors and the use of BoHV-4 as a vaccine-vector platform.
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Affiliation(s)
| | - Scott Parker
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Sarah Jacca
- Department of Medical-Veterinary Science, University of Parma, Parma, Italy
| | - Ryan W. Crump
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Konstantin Doronin
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Edguardo Hembrador
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Daniela Pompilio
- Department of Medical-Veterinary Science, University of Parma, Parma, Italy
| | - Giulia Tebaldi
- Department of Medical-Veterinary Science, University of Parma, Parma, Italy
| | - Ryan D. Estep
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Scott W. Wong
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Mark R. Buller
- Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri, United States of America
| | - Gaetano Donofrio
- Department of Medical-Veterinary Science, University of Parma, Parma, Italy
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Herbert MH, Squire CJ, Mercer AA. Poxviral ankyrin proteins. Viruses 2015; 7:709-38. [PMID: 25690795 PMCID: PMC4353913 DOI: 10.3390/v7020709] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 02/08/2023] Open
Abstract
Multiple repeats of the ankyrin motif (ANK) are ubiquitous throughout the kingdoms of life but are absent from most viruses. The main exception to this is the poxvirus family, and specifically the chordopoxviruses, with ANK repeat proteins present in all but three species from separate genera. The poxviral ANK repeat proteins belong to distinct orthologue groups spread over different species, and align well with the phylogeny of their genera. This distribution throughout the chordopoxviruses indicates these proteins were present in an ancestral vertebrate poxvirus, and have since undergone numerous duplication events. Most poxviral ANK repeat proteins contain an unusual topology of multiple ANK motifs starting at the N-terminus with a C-terminal poxviral homologue of the cellular F-box enabling interaction with the cellular SCF ubiquitin ligase complex. The subtle variations between ANK repeat proteins of individual poxviruses suggest an array of different substrates may be bound by these protein-protein interaction domains and, via the F-box, potentially directed to cellular ubiquitination pathways and possible degradation. Known interaction partners of several of these proteins indicate that the NF-κB coordinated anti-viral response is a key target, whilst some poxviral ANK repeat domains also have an F-box independent affect on viral host-range.
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Affiliation(s)
- Michael H Herbert
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand.
| | - Christopher J Squire
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand.
| | - Andrew A Mercer
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
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Israely T, Melamed S, Achdout H, Erez N, Politi B, Waner T, Lustig S, Paran N. TLR3 and TLR9 agonists improve postexposure vaccination efficacy of live smallpox vaccines. PLoS One 2014; 9:e110545. [PMID: 25350003 PMCID: PMC4211728 DOI: 10.1371/journal.pone.0110545] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 09/14/2014] [Indexed: 12/14/2022] Open
Abstract
Eradication of smallpox and discontinuation of the vaccination campaign resulted in an increase in the percentage of unvaccinated individuals, highlighting the need for postexposure efficient countermeasures in case of accidental or deliberate viral release. Intranasal infection of mice with ectromelia virus (ECTV), a model for human smallpox, is curable by vaccination with a high vaccine dose given up to 3 days postexposure. To further extend this protective window and to reduce morbidity, mice were vaccinated postexposure with Vaccinia-Lister, the conventional smallpox vaccine or Modified Vaccinia Ankara, a highly attenuated vaccine in conjunction with TLR3 or TLR9 agonists. We show that co-administration of the TLR3 agonist poly(I:C) even 5 days postexposure conferred protection, avoiding the need to increase the vaccination dose. Efficacious treatments prevented death, ameliorated disease symptoms, reduced viral load and maintained tissue integrity of target organs. Protection was associated with significant elevation of serum IFNα and anti-vaccinia IgM antibodies, modulation of IFNγ response, and balanced activation of NK and T cells. TLR9 agonists (CpG ODNs) were less protective than the TLR3 agonist poly(I:C). We show that activation of type 1 IFN by poly(I:C) and protection is achievable even without co-vaccination, requiring sufficient amount of the viral antigens of the infective agent or the vaccine. This study demonstrated the therapeutic potential of postexposure immune modulation by TLR activation, allowing to alleviate the disease symptoms and to further extend the protective window of postexposure vaccination.
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Affiliation(s)
- Tomer Israely
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Sharon Melamed
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Hagit Achdout
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Noam Erez
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Boaz Politi
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Trevor Waner
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Shlomo Lustig
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Nir Paran
- Department of Infectious diseases, Israel Institute for Biological Research, Ness-Ziona, Israel
- * E-mail:
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Parker S, Crump R, Foster S, Hartzler H, Hembrador E, Lanier ER, Painter G, Schriewer J, Trost LC, Buller RM. Co-administration of the broad-spectrum antiviral, brincidofovir (CMX001), with smallpox vaccine does not compromise vaccine protection in mice challenged with ectromelia virus. Antiviral Res 2014; 111:42-52. [PMID: 25128688 PMCID: PMC9533899 DOI: 10.1016/j.antiviral.2014.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/31/2014] [Accepted: 08/04/2014] [Indexed: 12/02/2022]
Abstract
Natural orthopoxvirus outbreaks such as vaccinia, cowpox, cattlepox and buffalopox continue to cause morbidity in the human population. Monkeypox virus remains a significant agent of morbidity and mortality in Africa. Furthermore, monkeypox virus’s broad host-range and expanding environs make it of particular concern as an emerging human pathogen. Monkeypox virus and variola virus (the etiological agent of smallpox) are both potential agents of bioterrorism. The first line response to orthopoxvirus disease is through vaccination with first-generation and second-generation vaccines, such as Dryvax and ACAM2000. Although these vaccines provide excellent protection, their widespread use is impeded by the high level of adverse events associated with vaccination using live, attenuated virus. It is possible that vaccines could be used in combination with antiviral drugs to reduce the incidence and severity of vaccine-associated adverse events, or as a preventive in individuals with uncertain exposure status or contraindication to vaccination. We have used the intranasal mousepox (ectromelia) model to evaluate the efficacy of vaccination with Dryvax or ACAM2000 in conjunction with treatment using the broad spectrum antiviral, brincidofovir (BCV, CMX001). We found that co-treatment with BCV reduced the severity of vaccination-associated lesion development. Although the immune response to vaccination was quantifiably attenuated, vaccination combined with BCV treatment did not alter the development of full protective immunity, even when administered two days following ectromelia challenge. Studies with a non-replicating vaccine, ACAM3000 (MVA), confirmed that BCV’s mechanism of attenuating the immune response following vaccination with live virus was, as expected, by limiting viral replication and not through inhibition of the immune system. These studies suggest that, in the setting of post-exposure prophylaxis, co-administration of BCV with vaccination should be considered a first response to a smallpox emergency in subjects of uncertain exposure status or as a means of reduction of the incidence and severity of vaccine-associated adverse events.
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Affiliation(s)
- Scott Parker
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States
| | - Ryan Crump
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States
| | - Scott Foster
- Chimerix Inc., 2505 Meridian Parkway, Suite 340, Durham, NC 27713, United States
| | - Hollyce Hartzler
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States
| | - Ed Hembrador
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States
| | - E Randall Lanier
- Chimerix Inc., 2505 Meridian Parkway, Suite 340, Durham, NC 27713, United States
| | - George Painter
- Chimerix Inc., 2505 Meridian Parkway, Suite 340, Durham, NC 27713, United States
| | - Jill Schriewer
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States
| | - Lawrence C Trost
- Chimerix Inc., 2505 Meridian Parkway, Suite 340, Durham, NC 27713, United States
| | - R Mark Buller
- Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO 63104, United States.
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Abstract
This review highlights ten "hot topics" in current antiviral research: (i) new nucleoside derivatives (i.e., PSI-352938) showing high potential as a direct antiviral against hepatitis C virus (HCV); (ii) cyclopropavir, which should be further pursued for treatment of human cytomegalovirus (HCMV) infections; (iii) North-methanocarbathymidine (N-MCT), with a N-locked conformation, showing promising activity against both α- and γ-herpesviruses; (iv) CMX001, an orally bioavailable prodrug of cidofovir with broad-spectrum activity against DNA viruses, including polyoma, adeno, herpes, and pox; (v) favipiravir, which is primarily pursued for the treatment of influenza virus infections, but also inhibits the replication of other RNA viruses, particularly (-)RNA viruses such as arena, bunya, and hanta; (vi) newly emerging antiarenaviral compounds which should be more effective (and less toxic) than the ubiquitously used ribavirin; (vii) antipicornavirus agents in clinical development (pleconaril, BTA-798, and V-073); (viii) natural products receiving increased attention as potential antiviral drugs; (ix) antivirals such as U0126 targeted at specific cellular kinase pathways [i.e., mitogen extracellular kinase (MEK)], showing activity against influenza and other viruses; and (x) two structurally unrelated compounds (i.e., LJ-001 and dUY11) with broad-spectrum activity against virtually all enveloped RNA and DNA viruses.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, B-3000, Leuven, Belgium.
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De Clercq E. Dancing with chemical formulae of antivirals: A panoramic view (Part 2). Biochem Pharmacol 2013; 86:1397-410. [DOI: 10.1016/j.bcp.2013.09.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 09/12/2013] [Accepted: 09/12/2013] [Indexed: 12/11/2022]
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Smee DF. Orthopoxvirus inhibitors that are active in animal models: an update from 2008 to 2012. Future Virol 2013; 8:891-901. [PMID: 24563659 PMCID: PMC3929309 DOI: 10.2217/fvl.13.76] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antiviral agents are being sought as countermeasures for the potential deliberate release of smallpox (variola) and monkeypox viruses, for the treatment of naturally acquired monkeypox virus infections, and as therapy for complications due to smallpox (live-attenuated vaccinia virus) vaccination or accidental infection after exposure to vaccinated persons. Reviews of the scientific literature spanning 1950-2008 have documented the progress made in developing small-animal models of poxvirus infection and identifying novel antiviral agents. Compounds of considerable interest include cidofovir, CMX001 and ST-246® (tecovirimat; SIGA Technologies, NY, USA). New inhibitors have been identified since 2008, most of which do not exhibit the kind of potency and selectivity required for drug development. Two promising agents include 4'-thioidoxuridine (a nucleoside analog) and mDEF201 (an adenovirus-vectored interferon). Compounds that have been effectively used in combination studies include vaccinia immune globulin, cidofovir, ST-246 and CMX001. In the future there may be an increase in experimental work using active compounds in combination.
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Affiliation(s)
- Donald F Smee
- Institute for Antiviral Research, Department of Animal, Dairy & Veterinary Sciences, Utah State University, Logan, UT, 84322-5600, USA, Tel.: +1 435 797 2897, ,
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De Clercq E. A cutting-edge view on the current state of antiviral drug development. Med Res Rev 2013; 33:1249-77. [PMID: 23495004 DOI: 10.1002/med.21281] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Prominent in the current stage of antiviral drug development are: (i) for human immunodeficiency virus (HIV), the use of fixed-dose combinations (FDCs), the most recent example being Stribild(TM); (ii) for hepatitis C virus (HCV), the pleiade of direct-acting antivirals (DAAs) that should be formulated in the most appropriate combinations so as to obtain a cure of the infection; (iii)-(v) new strategies (i.e., AIC316, AIC246, and FV-100) for the treatment of herpesvirus infections: herpes simplex virus (HSV), cytomegalovirus (CMV), and varicella-zoster virus (VZV), respectively; (vi) the role of a new tenofovir prodrug, tenofovir alafenamide (TAF) (GS-7340) for the treatment of HIV infections; (vii) the potential use of poxvirus inhibitors (CMX001 and ST-246); (viii) the usefulness of new influenza virus inhibitors (peramivir and laninamivir octanoate); (ix) the position of the hepatitis B virus (HBV) inhibitors [lamivudine, adefovir dipivoxil, entecavir, telbivudine, and tenofovir disoproxil fumarate (TDF)]; and (x) the potential of new compounds such as FGI-103, FGI-104, FGI-106, dUY11, and LJ-001 for the treatment of filoviruses (i.e., Ebola). Whereas for HIV and HCV therapy is aimed at multiple-drug combinations, for all other viruses, HSV, CMV, VZV, pox, influenza, HBV, and filoviruses, current strategies are based on the use of single compounds.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, B-3000, Leuven, Belgium.
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Parker S, Buller RM. A review of experimental and natural infections of animals with monkeypox virus between 1958 and 2012. Future Virol 2013; 8:129-157. [PMID: 23626656 DOI: 10.2217/fvl.12.130] [Citation(s) in RCA: 181] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Monkeypox virus (MPXV) was discovered in 1958 during an outbreak in an animal facility in Copenhagen, Denmark. Since its discovery, MPXV has revealed a propensity to infect and induce disease in a large number of animals within the mammalia class from pan-geographical locations. This finding has impeded the elucidation of the natural host, although the strongest candidates are African squirrels and/or other rodents. Experimentally, MPXV can infect animals via a variety of multiple different inoculation routes; however, the natural route of transmission is unknown and is likely to be somewhat species specific. In this review we have attempted to compile and discuss all published articles that describe experimental or natural infections with MPXV, dating from the initial discovery of the virus through to the year 2012. We further discuss the comparative disease courses and pathologies of the host species.
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Affiliation(s)
- Scott Parker
- Department of Molecular Microbiology & Immunology, Saint Louis University School of Medicine, 1100 S. Grand Blvd, Saint Louis, MO 63104, USA
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Abstract
As the threat of exposure to emerging and reemerging viruses within a naive population increases, it is vital that the basic mechanisms of pathogenesis and immune response be thoroughly investigated. By using animal models in this endeavor, the response to viruses can be studied in a more natural context to identify novel drug targets, and assess the efficacy and safety of new products. This is especially true in the advent of the Food and Drug Administration's animal rule. Although no one animal model is able to recapitulate all the aspects of human disease, understanding the current limitations allows for a more targeted experimental design. Important facets to be considered before an animal study are the route of challenge, species of animals, biomarkers of disease, and a humane endpoint. This chapter covers the current animal models for medically important human viruses, and demonstrates where the gaps in knowledge exist.
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Earl PL, Americo JL, Moss B. Lethal monkeypox virus infection of CAST/EiJ mice is associated with a deficient gamma interferon response. J Virol 2012; 86:9105-12. [PMID: 22696658 PMCID: PMC3416162 DOI: 10.1128/jvi.00162-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 06/05/2012] [Indexed: 11/20/2022] Open
Abstract
Monkeypox virus (MPXV) is endemic in Africa, where it causes disease in humans resembling smallpox. A recent importation of MPXV-infected animals into the United States raises the possibility of global spread. Rodents comprise the major reservoir of MPXV, and a variety of such animals, even those native to North America, are susceptible. In contrast, common inbred strains of mice, including BALB/c and C57BL/6, are greatly resistant to MPXV. However, several inbred strains of mice derived from wild mice, including CAST/EiJ, exhibit morbidity and mortality at relatively low inoculums of MPXV. Elucidating the basis for the susceptibility of CAST/EiJ mice could contribute to an understanding of MPXV pathogenicity and host defense mechanisms and enhance the value of this mouse strain as a model system for evaluation of therapeutics and vaccines. Here we compared virus dissemination and induced cytokine production in CAST/EiJ mice to those in the resistant BALB/c strain. Following intranasal infection, robust virus replication occurred in the lungs of both strains, although a relatively higher inoculum was required for BALB/c. However, while spread to other internal organs was rapid and efficient in CAST/EiJ mice, the virus was largely restricted to the lungs in BALB/c mice. Gamma interferon (IFN-γ) and CCL5 were induced in lungs of BALB/c mice concomitant with virus replication but not in CAST/EiJ mice. The importance of IFN-γ in protection against MPXV disease was demonstrated by the intranasal administration of the mouse cytokine to CAST/EiJ mice and the resulting protection against MPXV. Furthermore, C57BL/6 mice with inactivation of the IFN-γ gene or the IFN-γ receptor gene exhibited enhanced sensitivity to MPXV.
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Affiliation(s)
- Patricia L Earl
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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64
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De Clercq E. Human viral diseases: what is next for antiviral drug discovery? Curr Opin Virol 2012; 2:572-9. [PMID: 22846888 DOI: 10.1016/j.coviro.2012.07.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/10/2012] [Indexed: 01/30/2023]
Abstract
For the treatment of human immunodeficiency virus (HIV) infections for which there are ample drugs available, the immediate future lies in a once-daily combination pill containing three or four active ingredients. This strategy may also be envisaged for the treatment of hepatitis C virus (HCV) infections as soon as we have at hand the appropriate direct-acting antiviral agents (DAAs) to be combined. A combination drug therapy is generally not entertained for other viruses. Yet, new drugs are at the horizon for the treatment of herpes simplex virus (HSV), varicella-zoster virus (VZV), poxvirus, hepatitis B virus (HBV), influenza and enveloped viruses-at-large.
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Affiliation(s)
- Erik De Clercq
- Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
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65
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Israely T, Paran N, Lustig S, Erez N, Politi B, Shafferman A, Melamed S. A single cidofovir treatment rescues animals at progressive stages of lethal orthopoxvirus disease. Virol J 2012; 9:119. [PMID: 22709563 PMCID: PMC3409050 DOI: 10.1186/1743-422x-9-119] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 06/18/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In an event of a smallpox outbreak in humans, the window for efficacious treatment by vaccination with vaccinia viruses (VACV) is believed to be limited to the first few days post-exposure (p.e.). We recently demonstrated in a mouse model for human smallpox, that active immunization 2-3 days p.e. with either VACV-Lister or modified VACV Ankara (MVA) vaccines, can rescue animals from lethal challenge of ectromelia virus (ECTV), the causative agent of mousepox. The present study was carried out in order to determine whether a single dose of the anti-viral cidofovir (CDV), administered at different times and doses p.e. either alone or in conjunction with active vaccination, can rescue ECTV infected mice. METHODS Animals were infected intranasally with ECTV, treated on different days with various single CDV doses and monitored for morbidity, mortality and humoral response. In addition, in order to determine the influence of CDV on the immune response following vaccination, both the "clinical take", IFN-gamma and IgG Ab levels in the serum were evaluated as well as the ability of the mice to withstand a lethal challenge of ECTV. Finally the efficacy of a combined treatment regime of CDV and vaccination p.e. was determined. RESULTS A single p.e. CDV treatment is sufficient for protection depending on the initiation time and dose (2.5 - 100 mg/kg) of treatment. Solid protection was achieved by a low dose (5 mg/kg) CDV treatment even if given at day 6 p.e., approximately 4 days before death of the control infected untreated mice (mean time to death (MTTD) 10.2). At the same time point complete protection was achieved by single treatment with higher doses of CDV (25 or 100 mg/kg). Irrespective of treatment dose, all surviving animals developed a protective immune response even when the CDV treatment was initiated one day p.e.. After seven days post treatment with the highest dose (100 mg/kg), virus was still detected in some organs (e.g. lung and liver) yet all animals survived, suggesting that efficacious single CDV treatment requires a potent immune system. The combination of CDV and vaccination provided no additional protection over CDV alone. Yet, combining CDV and vaccination maintained vaccination efficacy. CONCLUSIONS Altogether, our data substantiate the feasibility of single post-exposure antiviral treatment to face orthopoxvirus infection.
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Affiliation(s)
- Tomer Israely
- Israel Institute for Biological Research, Ness-ziona, Israel
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66
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Miller MA, Stabenow JM, Parvathareddy J, Wodowski AJ, Fabrizio TP, Bina XR, Zalduondo L, Bina JE. Visualization of murine intranasal dosing efficiency using luminescent Francisella tularensis: effect of instillation volume and form of anesthesia. PLoS One 2012; 7:e31359. [PMID: 22384012 PMCID: PMC3286442 DOI: 10.1371/journal.pone.0031359] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 01/06/2012] [Indexed: 11/18/2022] Open
Abstract
Intranasal instillation is a widely used procedure for pneumonic delivery of drugs, vaccine candidates, or infectious agents into the respiratory tract of research mice. However, there is a paucity of published literature describing the efficiency of this delivery technique. In this report we have used the murine model of tularemia, with Francisella tularensis live vaccine strain (FTLVS) infection, to evaluate the efficiency of pneumonic delivery via intranasal dosing performed either with differing instillation volumes or different types of anesthesia. FTLVS was rendered luminescent via transformation with a reporter plasmid that constitutively expressed the Photorhabdus luminescens lux operon from a Francisella promoter. We then used an IVIS Spectrum whole animal imaging system to visualize FT dissemination at various time points following intranasal instillation. We found that instillation of FT in a dose volume of 10 µl routinely resulted in infection of the upper airways but failed to initiate infection of the pulmonary compartment. Efficient delivery of FT into the lungs via intranasal instillation required a dose volume of 50 µl or more. These studies also demonstrated that intranasal instillation was significantly more efficient for pneumonic delivery of FTLVS in mice that had been anesthetized with inhaled (isoflurane) vs. parenteral (ketamine/xylazine) anesthesia. The collective results underscore the need for researchers to consider both the dose volume and the anesthesia type when either performing pneumonic delivery via intranasal instillation, or when comparing studies that employed this technique.
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Affiliation(s)
- Mark A Miller
- The University of Tennessee Health Science Center, Memphis, Tennessee, United States of America.
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67
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Parker S, Chen NG, Foster S, Hartzler H, Hembrador E, Hruby D, Jordan R, Lanier R, Painter G, Painter W, Sagartz JE, Schriewer J, Mark Buller R. Evaluation of disease and viral biomarkers as triggers for therapeutic intervention in respiratory mousepox - an animal model of smallpox. Antiviral Res 2012; 94:44-53. [PMID: 22381921 PMCID: PMC3722602 DOI: 10.1016/j.antiviral.2012.02.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 12/16/2011] [Accepted: 02/08/2012] [Indexed: 11/26/2022]
Abstract
The human population is currently faced with the potential use of natural or recombinant variola and monkeypox viruses as biological weapons. Furthermore, the emergence of human monkeypox in Africa and its expanding environs poses a significant natural threat. Such occurrences would require therapeutic and prophylactic intervention with antivirals to minimize morbidity and mortality of exposed populations. Two orally-bioavailable antivirals are currently in clinical trials; namely CMX001, an ether-lipid analog of cidofovir with activity at the DNA replication stage and ST-246, a novel viral egress inhibitor. Both of these drugs have previously been evaluated in the ectromelia/mousepox system; however, the trigger for intervention was not linked to a disease biomarker or a specific marker of virus replication. In this study we used lethal, intranasal, ectromelia virus infections of C57BL/6 and hairless SKH1 mice to model human disease and evaluate exanthematous rash (rash) as an indicator to initiate antiviral treatment. We show that significant protection can be provided to C57BL/6 mice by CMX001 or ST-246 when therapy is initiated on day 6 post infection or earlier. We also show that significant protection can be provided to SKH1 mice treated with CMX001 at day 3 post infection or earlier, but this is four or more days before detection of rash (ST-246 not tested). Although in this model rash could not be used as a treatment trigger, viral DNA was detected in blood by day 4 post infection and in the oropharyngeal secretions (saliva) by day 2–3 post infection – thus providing robust and specific markers of virus replication for therapy initiation. These findings are discussed in the context of current respiratory challenge animal models in use for the evaluation of poxvirus antivirals.
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Affiliation(s)
- Scott Parker
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, MO 63104, United States
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68
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de Wit E, Munster VJ, Metwally SA, Feldmann H. Assessment of rodents as animal models for Reston ebolavirus. J Infect Dis 2011; 204 Suppl 3:S968-72. [PMID: 21987777 DOI: 10.1093/infdis/jir330] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The emergence of Reston ebolavirus (REBOV) in domestic swine in the Philippines has caused a renewed interest in REBOV pathogenicity. Here, the use of different rodent species as animal disease models for REBOV was investigated. BALB/c and STAT1(-)(/-) mice, Hartley guinea pigs, and Syrian hamsters were inoculated intraperitoneally with REBOV strain Pennsylvania or Reston08-A. Although virus replication occurred in guinea pigs, hamsters, and STAT1(-/-) mice, progression to disease was only observed in STAT1(-)(/-) mice. Moreover, REBOV Pennsylvania was more pathogenic than REBOV Reston08-A in this model. Thus, STAT1(-)(/-) mice may be used for research of REBOV pathogenicity and intervention strategies.
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Affiliation(s)
- Emmie de Wit
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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69
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Keckler MS, Carroll DS, Gallardo-Romero NF, Lash RR, Salzer JS, Weiss SL, Patel N, Clemmons CJ, Smith SK, Hutson CL, Karem KL, Damon IK. Establishment of the black-tailed prairie dog (Cynomys ludovicianus) as a novel animal model for comparing smallpox vaccines administered preexposure in both high- and low-dose monkeypox virus challenges. J Virol 2011; 85:7683-98. [PMID: 21632764 PMCID: PMC3147922 DOI: 10.1128/jvi.02174-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 05/21/2011] [Indexed: 11/20/2022] Open
Abstract
The 2003 monkeypox virus (MPXV) outbreak and subsequent laboratory studies demonstrated that the black-tailed prairie dog is susceptible to MPXV infection and that the ensuing rash illness is similar to human systemic orthopoxvirus (OPXV) infection, including a 7- to 9-day incubation period and, likely, in some cases a respiratory route of infection; these features distinguish this model from others. The need for safe and efficacious vaccines for OPVX in areas where it is endemic or epidemic is important to protect an increasingly OPXV-naïve population. In this study, we tested current and investigational smallpox vaccines for safety, induction of anti-OPXV antibodies, and protection against mortality and morbidity in two MPXV challenges. None of the smallpox vaccines caused illness in this model, and all vaccinated animals showed anti-OPXV antibody responses and neutralizing antibody. We tested vaccine efficacy by challenging the animals with 10(5) or 10(6) PFU Congo Basin MPXV 30 days postvaccination and evaluating morbidity and mortality. Our results demonstrated that vaccination with either Dryvax or Acambis2000 protected the animals from death with no rash illness. Vaccination with IMVAMUNE also protected the animals from death, albeit with (modified) rash illness. Based on the results of this study, we believe prairie dogs offer a novel and potentially useful small animal model for the safety and efficacy testing of smallpox vaccines in pre- and postexposure vaccine testing, which is important for public health planning.
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Affiliation(s)
- M S Keckler
- Centers for Disease Control and Prevention, Division of High-Consequence Pathogens and Pathology, Poxvirus and Rabies Branch, 1600 Clifton Road, Mailstop G-06, Atlanta, GA 30333, USA.
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70
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Duraffour S, Matthys P, van den Oord JJ, De Schutter T, Mitera T, Snoeck R, Andrei G. Study of camelpox virus pathogenesis in athymic nude mice. PLoS One 2011; 6:e21561. [PMID: 21738709 PMCID: PMC3125194 DOI: 10.1371/journal.pone.0021561] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 06/02/2011] [Indexed: 11/29/2022] Open
Abstract
Camelpox virus (CMLV) is the closest known orthopoxvirus genetically related to variola virus. So far, CMLV was restricted to camelids but, recently, three human cases of camelpox have been described in India, highlighting the need to pursue research on its pathogenesis, which has been hampered by the lack of small animal models. Here, we confirm that NMRI immunocompetent mice are resistant to intranasal (i.n.) CMLV infection. However, we demonstrate that CMLV induced a severe disease following i.n. challenge of athymic nude mice, which was accompanied with a failure in gaining weight, leading to euthanasia of the animals. On the other hand, intracutaneous (i.c.) infection resulted in disease development without impacting the body weight evolution. CMLV replication in tissues and body fluids was confirmed in the two models. We further analyzed innate immune and B cell responses induced in the spleen and draining lymph nodes after exposure to CMLV. In both models, strong increases in CD11b+F4/80+ macrophages were seen in the spleen, while neutrophils, NK and B cell responses varied between the routes of infection. In the lymph nodes, the magnitude of CD11c+CD8α+ lymphoid and CD11c+CD11b+ myeloid dendritic cell responses increased in i.n. challenged animals. Analysis of cytokine profiles revealed significant increases of interleukin (IL)-6 and IL-18 in the sera of infected animals, while those of other cytokines were similar to uninfected controls. The efficacy of two antivirals (cidofovir or HPMPC, and its 2, 6-diaminopurine analog) was evaluated in both models. HPMPC was the most effective molecule affording 100% protection from morbidity. It appeared that both treatments did not affect immune cell responses or cytokine expression. In conclusion, we demonstrated that immunodeficient mice are permissive for CMLV propagation. These results provide a basis for studying the pathogenesis of CMLV, as well as for evaluating potential antiviral therapies in an immunodeficiency context.
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Affiliation(s)
- Sophie Duraffour
- Rega Institute, Laboratory of Virology and Chemotherapy, K.U.L, Leuven, Belgium.
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71
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Torres E, Duque MD, Camps P, Naesens L, Calvet T, Font-Bardia M, Vázquez S. Polycyclic N-benzamido imides with potent activity against vaccinia virus. ChemMedChem 2011; 5:2072-8. [PMID: 20967819 PMCID: PMC7162373 DOI: 10.1002/cmdc.201000306] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The synthesis and antiviral activity of a series of novel polycyclic analogues of the orthopoxvirus egress inhibitor tecovirimat (ST-246) is presented. Several of these compounds display sub-micromolar activity against vaccinia virus, and were more potent than cidofovir (CDV). The more active compounds were about 10-fold more active than CDV, with minimum cytotoxic concentrations above 100 μM. Chemical manipulations of the two carbon-carbon double bonds present in the compounds were carried out to further explore the structure-activity relationships of these new polycyclic imides. Hydrogenation of the two carbon-carbon double bonds decreases antiviral activity, whereas either cyclopropanation or epoxidation of the double bonds fully eliminates the antiviral activity.
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Affiliation(s)
- Eva Torres
- Institute of Biomedicine, Universitat de Barcelona, Spain
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72
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Abstract
The eradication of smallpox, one of the great triumphs of medicine, was accomplished through the prophylactic administration of live vaccinia virus, a comparatively benign relative of variola virus, the causative agent of smallpox. Nevertheless, recent fears that variola virus may be used as a biological weapon together with the present susceptibility of unimmunized populations have spurred the development of new-generation vaccines that are safer than the original and can be produced by modern methods. Predicting the efficacy of such vaccines in the absence of human smallpox, however, depends on understanding the correlates of protection. This review outlines the biology of poxviruses with particular relevance to vaccine development, describes protein targets of humoral and cellular immunity, compares animal models of orthopoxvirus disease with human smallpox, and considers the status of second- and third-generation smallpox vaccines.
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Affiliation(s)
- Bernard Moss
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-3210, USA.
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73
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Hutson CL, Damon IK. Monkeypox virus infections in small animal models for evaluation of anti-poxvirus agents. Viruses 2010; 2:2763-76. [PMID: 21994638 PMCID: PMC3185589 DOI: 10.3390/v2122763] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 12/08/2010] [Accepted: 12/10/2010] [Indexed: 12/17/2022] Open
Abstract
An ideal animal model for the study of a human disease is one which utilizes a route of infection that mimics the natural transmission of the pathogen; the ability to obtain disease with an infectious dose equivalent to that causing disease in humans; as well having a disease course, morbidity and mortality similar to that seen with human disease. Additionally, the animal model should have a mode(s) of transmission that mimics human cases. The development of small animal models for the study of monkeypox virus (MPXV) has been quite extensive for the relatively short period of time this pathogen has been known, although only a few of these models have been used to study anti-poxvirus agents. We will review those MPXV small animal models that have been developed thus far for the study of therapeutic agents.
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Affiliation(s)
- Christina L Hutson
- Poxvirus and Rabies Branch, Centers for Disease Control and Prevention, 1600 Clifton Rd. MS-G06 Atlanta, GA 30029, USA; E-Mail:
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74
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Abstract
Smallpox is a human disease caused by infection with variola virus, a member of the genus Orthopoxvirus. Although smallpox has been eradicated, concern that it might be reintroduced through bioterrorism has therefore led to intensive efforts to develop new vaccines and antiviral drugs against this disease. Because these vaccines and therapeutics cannot be tested in human trials, it is necessary to test such medical countermeasures in different animal models. Although several orthopoxviruses cause disease in laboratory animals, only rabbitpox virus (RPXV) infection of rabbits shows patterns of natural airborne transmission similar to smallpox. Studies have shown that a smallpox-like disease can be produced in rabbits in a controlled fashion through exposure to a small-particle RPXV aerosol, and rabbitpox spreads from animal to animal by the airborne route in a laboratory setting. This model can therefore be utilized to test drugs and vaccines against variola virus and other aerosolized orthopoxviruses.
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Affiliation(s)
- Aysegul Nalca
- Center for Aerobiological Sciences, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA.
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75
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Parker S, Siddiqui AM, Painter G, Schriewer J, Buller RM. Ectromelia virus infections of mice as a model to support the licensure of anti-orthopoxvirus therapeutics. Viruses 2010; 2:1918-1932. [PMID: 21994714 PMCID: PMC3185751 DOI: 10.3390/v2091918] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/30/2010] [Accepted: 08/31/2010] [Indexed: 12/02/2022] Open
Abstract
The absence of herd immunity to orthopoxviruses and the concern that variola or monkeypox viruses could be used for bioterroristic activities has stimulated the development of therapeutics and safer prophylactics. One major limitation in this process is the lack of accessible human orthopoxvirus infections for clinical efficacy trials; however, drug licensure can be based on orthopoxvirus animal challenge models as described in the "Animal Efficacy Rule". One such challenge model uses ectromelia virus, an orthopoxvirus, whose natural host is the mouse and is the etiological agent of mousepox. The genetic similarity of ectromelia virus to variola and monkeypox viruses, the common features of the resulting disease, and the convenience of the mouse as a laboratory animal underscores its utility in the study of orthopoxvirus pathogenesis and in the development of therapeutics and prophylactics. In this review we outline how mousepox has been used as a model for smallpox. We also discuss mousepox in the context of mouse strain, route of infection, infectious dose, disease progression, and recovery from infection.
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Affiliation(s)
- Scott Parker
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO, 63104, USA; E-Mails: (S.P.); (A.M.S.); (J.S.)
| | - Akbar M. Siddiqui
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO, 63104, USA; E-Mails: (S.P.); (A.M.S.); (J.S.)
| | - George Painter
- Chimerix Inc., 2505 Meridian Park Way, Suite 340, Durham, NC, 27713, USA; E-Mail:
| | - Jill Schriewer
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO, 63104, USA; E-Mails: (S.P.); (A.M.S.); (J.S.)
| | - R. Mark Buller
- Department of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, 1100 S. Grand Blvd., St. Louis, MO, 63104, USA; E-Mails: (S.P.); (A.M.S.); (J.S.)
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76
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Meseda CA, Weir JP. Third-generation smallpox vaccines: challenges in the absence of clinical smallpox. Future Microbiol 2010; 5:1367-82. [DOI: 10.2217/fmb.10.98] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Smallpox, a disease caused by variola virus, is estimated to have killed hundreds of millions to billions of people before it was certified as eradicated in 1980. However, there has been renewed interest in smallpox vaccine development due in part to zoonotic poxvirus infections and the possibility of a re-emergence of smallpox, as well as the fact that first-generation smallpox vaccines are associated with relatively rare, but severe, adverse reactions in some vaccinees. An understanding of the immune mechanisms of vaccine protection and the use of suitable animal models for vaccine efficacy assessment are paramount to the development of safer and effective smallpox vaccines. This article focuses on studies aimed at understanding the immune responses elicited by vaccinia virus and the various animal models that can be used to evaluate smallpox vaccine efficacy. Harnessing this information is necessary to assess the effectiveness and potential usefulness of new-generation smallpox vaccines.
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Affiliation(s)
| | - Jerry P Weir
- Division of Viral Products, Center for Biologics Evaluation & Research, USFDA, 1401 Rockville Pike, HFM-457, Rockville, MD 20852, USA
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77
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Americo JL, Moss B, Earl PL. Identification of wild-derived inbred mouse strains highly susceptible to monkeypox virus infection for use as small animal models. J Virol 2010; 84:8172-80. [PMID: 20519404 PMCID: PMC2916512 DOI: 10.1128/jvi.00621-10] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 05/20/2010] [Indexed: 11/20/2022] Open
Abstract
Infection with monkeypox virus (MPXV) causes disease manifestations in humans that are similar, although usually less severe, than those of smallpox. Since routine vaccination for smallpox ceased more than 30 years ago, there is concern that MPXV could be used for bioterrorism. Thus, there is a need to develop animal models to study MPXV infection. Accordingly, we screened 38 inbred mouse strains for susceptibility to MPXV. Three highly susceptible wild-derived inbred strains were identified, of which CAST/EiJ was further developed as a model. Using an intranasal route of infection with an isolate of the Congo Basin clade of MPXV, CAST/EiJ mice exhibited weight loss, morbidity, and death in a dose-dependent manner with a calculated 50% lethal dose (LD(50)) of 680 PFU, whereas there were no deaths of BALB/c mice at a 10,000-fold higher dose. CAST/EiJ mice exhibited greater MPXV sensitivity when infected via the intraperitoneal route, with an LD(50) of 14 PFU. Both routes resulted in MPXV replication in the lung, spleen, and liver. Intranasal infection with an isolate of the less-pathogenic West African clade yielded an LD(50) of 7,600 PFU. The immune competence of CAST/EiJ mice was established by immunization with vaccinia virus, which induced antigen-specific T- and B-lymphocyte responses and fully protected mice from lethal doses of MPXV. The new mouse model has the following advantages for studying pathogenesis of MPXV, as well as for evaluation of potential vaccines and therapeutics: relative sensitivity to MPXV through multiple routes, genetic homogeneity, available immunological reagents, and commercial production.
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Affiliation(s)
- Jeffrey L. Americo
- Laboratory of Viral Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Bernard Moss
- Laboratory of Viral Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Patricia L. Earl
- Laboratory of Viral Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
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