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Robert Jordan - One of the best experts on this subject based on the ideXlab platform.
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CHAPTER 4:Discovery and Development of Antiviral Drugs for Treatment of Pathogenic Human Orthopoxvirus Infections
Drug Discovery, 2013Co-Authors: Robert JordanAbstract:Smallpox, a devastating disease with mortality rates of upwards of 30%, ravaged humanity for thousands of years until it was eradicated in the latter half of the twentieth century by a successful vaccination campaign sponsored by the World Health Organization. Smallpox was caused by infection with variola virus, one of several Orthopoxviruses that infect humans and cause disease. Although smallpox no longer exists in the environment, concern that variola virus or a related Orthopoxvirus could be developed into a bioweapon prompted the US government to sponsor research into developing antiviral drugs to treat variola virus infection. Antiviral drug development for Orthopoxvirus infections is hampered by the lack of human disease, requiring the use of animal models to establish pharmacokinetic–pharmacodynamic relationships to guide effective human dosing strategies. Cidofovir, CMX001 and ST‐246 are clinical‐stage compounds currently being evaluated for the treatment of pathogenic Orthopoxvirus infections. Cidofovir is an acyclic nucleoside phosphonate that targets the viral polymerase and CMX001 is an oral prodrug of cidofovir designed to improve oral bioavailability and safety. ST‐246 is a novel chemical entity that blocks viral egress. Although all three compounds are effective at treating Orthopoxvirus infections in animal models, and are safe and well tolerated in human clinical trials, establishing effective human dosing strategies using animal efficacy data remains a major challenge for the development of these therapeutics.
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Effective antiviral treatment of systemic Orthopoxvirus disease: ST-246 treatment of prairie dogs infected with monkeypox virus
Journal of virology, 2011Co-Authors: Scott K Smith, Darin S Carroll, Zach Braden, Robert Jordan, Dennis E. Hruby, Josh Self, Sonja Weiss, Russell L. Regnery, Whitni Davidson, Inger K DamonAbstract:Smallpox preparedness research has led to development of antiviral therapies for treatment of serious Orthopoxvirus infections. Monkeypox virus is an emerging, zoonotic Orthopoxvirus which can cause severe and transmissible disease in humans, generating concerns for public health. Monkeypox virus infection results in a systemic, febrile-rash illness closely resembling smallpox. Currently, there are no small-molecule antiviral therapeutics approved to treat Orthopoxvirus infections of humans. The prairie dog, using monkeypox virus as a challenge virus, has provided a valuable nonhuman animal model in which monkeypox virus infection closely resembles human systemic Orthopoxvirus illness. Here, we assess the efficacy of the antiOrthopoxvirus compound ST-246 in prairie dogs against a monkeypox virus challenge of 65 times the 50% lethal dose (LD(50)). Animals were infected intranasally and administered ST-246 for 14 days, beginning on days 0, 3, or after rash onset. Swab and blood samples were collected every 2 days and analyzed for presence of viral DNA by real-time PCR and for viable virus by tissue culture. Seventy-five percent of infected animals that received vehicle alone succumbed to infection. One hundred percent of animals that received ST-246 survived challenge, and animals that received treatment before symptom onset remained largely asymptomatic. Viable virus and viral DNA were undetected or at greatly reduced levels in animals that began treatment on 0 or 3 days postinfection, compared to control animals or animals treated post-rash onset. Animals treated after rash onset manifested illness, but all recovered. Our results indicate that ST-246 can be used therapeutically, following onset of rash illness, to treat systemic Orthopoxvirus infections.
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Single-Dose Safety and Pharmacokinetics of ST-246, a Novel Orthopoxvirus Egress Inhibitor
Antimicrobial agents and chemotherapy, 2008Co-Authors: Robert Jordan, Deborah Tien, Tove' C. Bolken, Kevin F. Jones, Shanthakumar R. Tyavanagimatt, Josef Strasser, Annie Frimm, Michael L. Corrado, Phoebe G. Strome, Dennis E. HrubyAbstract:ST-246 is a novel, potent Orthopoxvirus egress inhibitor that is being developed to treat pathogenic Orthopoxvirus infections of humans. This phase I, double-blind, randomized, placebo-controlled single ascending dose study (first time with humans) was conducted to determine the safety, tolerability, and pharmacokinetics of ST-246 in healthy human volunteers. ST-246 was administered in single oral doses of 500, 1,000, and 2,000 mg to fasting healthy volunteers and 1,000 mg to nonfasting healthy volunteers. ST-246 was generally well tolerated with no serious adverse events, and no subject was withdrawn from the study due to ST-246. The most commonly reported drug-related adverse event was neutropenia, which was found, upon further analysis, not to be treatment related. ST-246 was readily absorbed following oral administration with mean times to maximum concentration from 2 h to 3 h. Absorption was greater in nonfasting volunteers than in fasting volunteers. Administration of ST-246 resulted in exposure levels predicted to be sufficient for inhibiting Orthopoxvirus replication compared to exposure levels in nonhuman primates in which ST-246 protected animals from lethal Orthopoxvirus infection.
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Activity of the anti-Orthopoxvirus compound ST-246 against vaccinia, cowpox and camelpox viruses in cell monolayers and organotypic raft cultures.
Antiviral therapy, 2007Co-Authors: Sophie Duraffour, Jean Marc Crance, Robert Jordan, Dennis E. Hruby, Robert Snoeck, Rita Vos, Joost Van Den Oord, Daniel Garin, Erik De Clercq, Graciela AndreiAbstract:Background The potential use of variola virus as a biological weapon has renewed efforts in the development of antiviral agents against Orthopoxviruses. ST-246 [4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-di oxo-4,6-ethenocycloprop [f]isoindol-2(1 H)-yl)-benzamide] is an anti-Orthopoxvirus compound active against several Orthopoxviruses including vaccinia virus (VV), cowpox virus (CPV), camelpox virus (CMLV), ectromelia virus (ECTV) and variola virus in cell culture. The compound has been shown to inhibit the release of extracellular virus by targeting the F13L W protein and to protect mice from W, CPV and ECTV Orthopoxvirus-induced disease. Methods The antiviral activity of ST-246 was assessed against extracellular and intracellular W, CPV and CMLV production in human embryonic lung (HEL) fibroblasts and primary human keratinocyte (PHK) cell monolayers, as well as in three-dimensional raft cultures. Results ST-246 inhibited preferentially the production of extracellular virus compared with intracellular virus production in HEL and PHK cells (for W) and in PHK cells (for CMLV). In organotypic epithelial raft cultures, ST-246 at 20 microg/ml inhibited extracellular W and CMLV production by 6 logs, whereas intracellular virus yield was reduced by 2 logs. In the case of CPV, both extracellular and intracellular virus production were completely inhibited by ST-246 at 20 microg/ml. Histological sections of the infected rafts, treated with increasing amounts of drug, confirmed the antiviral activity of ST-246: the epithelium was protected and there was no evidence of viral infection. Electron microscopic examination confirmed the absence of intracellular enveloped virus forms in W-, CPV- and CMLV-infected cells treated with 10 microg/ml of ST-246. Conclusions These data indicate that ST-246 is a potent anti-Orthopoxvirus compound; the mode of inhibition is dependent on the virus and cell type.
Inger K Damon - One of the best experts on this subject based on the ideXlab platform.
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Investigation of the First Laboratory-Acquired Human Cowpox Virus Infection in the United
2016Co-Authors: Mary G. Reynolds, Inger K DamonAbstract:Background. Cowpox virus is an Orthopoxvirus that can cause infections in humans and a variety of animals. Infections occur in Eurasia; infections in humans and animals have not been reported in the United States. This report describes the occurrence of the first known human case of laboratory-acquired cowpox virus infection in the United States and the ensuing investigation. Methods. The patient and laboratory personnel were interviewed, and laboratory activities were reviewed. Real-time polymerase chain reaction (PCR) and serologic assays were used to test the patient’s specimens. PCR assays were used to test specimens obtained during the investigation. Results. A specimen from the patient’s lesion tested positive for cowpox virus DNA. Genome sequencing revealed a recombinant region consistent with a strain of cowpox virus stored in the research laboratory’s freezer. Cowpox virus contamination was detected in 6 additional laboratory stocks of viruses. Orthopoxvirus DNA was present in 3 of 20 environmental swabs taken from laboratory surfaces. Conclusions. The handling of contaminated reagents or contact with contaminated surfaces was likely the mode of transmission. Delays in recognition and diagnosis of this infection in a laboratory researcher underscor
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Orthopoxvirus variola infection of cynomys ludovicianus north american black tailed prairie dog
Virology, 2013Co-Authors: Darin S Carroll, Victoria A Olson, Inger K Damon, Scott K Smith, Zach Braden, Nishi Patel, Jason Abel, Kevin L KaremAbstract:Since the eradication of Smallpox, researchers have attempted to study Orthopoxvirus pathogenesis and immunity in animal models in order to correlate results human smallpox. A solely human pathogen, Orthopoxvirus variola fails to produce authentic smallpox illness in any other animal species tested to date. In 2003, an outbreak in the USA of Orthopoxvirus monkeypox, revealed the susceptibility of the North American black-tailed prairie dog (Cynomys ludovicianus) to infection and fulminate disease. Prairie dogs infected with Orthopoxvirus monkeypox present with a clinical scenario similar to ordinary smallpox, including prodrome, rash, and high mortality. This study examines if Black-tailed prairie dogs can become infected with O. variola and serve as a surrogate model for the study of human smallpox disease. Substantive evidence of infection is found in immunological seroconversion of animals to either intranasal or intradermal challenges with O. variola, but in the absence of overt illness.
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Effective antiviral treatment of systemic Orthopoxvirus disease: ST-246 treatment of prairie dogs infected with monkeypox virus
Journal of virology, 2011Co-Authors: Scott K Smith, Darin S Carroll, Zach Braden, Robert Jordan, Dennis E. Hruby, Josh Self, Sonja Weiss, Russell L. Regnery, Whitni Davidson, Inger K DamonAbstract:Smallpox preparedness research has led to development of antiviral therapies for treatment of serious Orthopoxvirus infections. Monkeypox virus is an emerging, zoonotic Orthopoxvirus which can cause severe and transmissible disease in humans, generating concerns for public health. Monkeypox virus infection results in a systemic, febrile-rash illness closely resembling smallpox. Currently, there are no small-molecule antiviral therapeutics approved to treat Orthopoxvirus infections of humans. The prairie dog, using monkeypox virus as a challenge virus, has provided a valuable nonhuman animal model in which monkeypox virus infection closely resembles human systemic Orthopoxvirus illness. Here, we assess the efficacy of the antiOrthopoxvirus compound ST-246 in prairie dogs against a monkeypox virus challenge of 65 times the 50% lethal dose (LD(50)). Animals were infected intranasally and administered ST-246 for 14 days, beginning on days 0, 3, or after rash onset. Swab and blood samples were collected every 2 days and analyzed for presence of viral DNA by real-time PCR and for viable virus by tissue culture. Seventy-five percent of infected animals that received vehicle alone succumbed to infection. One hundred percent of animals that received ST-246 survived challenge, and animals that received treatment before symptom onset remained largely asymptomatic. Viable virus and viral DNA were undetected or at greatly reduced levels in animals that began treatment on 0 or 3 days postinfection, compared to control animals or animals treated post-rash onset. Animals treated after rash onset manifested illness, but all recovered. Our results indicate that ST-246 can be used therapeutically, following onset of rash illness, to treat systemic Orthopoxvirus infections.
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Detection of North American Orthopoxviruses by real time-PCR
Virology Journal, 2011Co-Authors: Nadia F Gallardo-romero, Ginny L. Emerson, Andres Velasco-villa, Sonja L Weiss, Darin S Carroll, Christine M Hughes, Inger K Damon, Yu Li, Kevin L Karem, Victoria A OlsonAbstract:The prevalence of North American Orthopoxviruses in nature is unknown and may be more difficult to ascertain due to wide spread use of vaccinia virus recombinant vaccines in the wild. A real time PCR assay was developed to allow for highly sensitive and specific detection of North American Orthopoxvirus DNA in animal tissues and bodily fluids. This method is based on the amplification of a 156 bp sequence within a myristylated protein, highly conserved within the North American Orthopoxviruses but distinct from orthologous genes present in other Orthopoxviruses. The analytical sensitivity was 1.1 fg for Volepox virus DNA, 1.99 fg for Skunkpox virus DNA, and 6.4 fg for Raccoonpox virus DNA with a 95% confidence interval. Our assay did not cross-react with other Orthopoxviruses or ten diverse representatives of the Chordopoxvirinae subfamily. This new assay showed more sensitivity than tissue culture tests, and was capable of differentiating North American Orthopoxviruses from other members of Orthopoxvirus . Thus, our assay is a promising tool for highly sensitive and specific detection of North American Orthopoxviruses in the United States and abroad.
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Amplification refractory mutation system PCR assays for the detection of variola and Orthopoxvirus
Journal of virological methods, 2004Co-Authors: David Pulford, Inger K Damon, Hermann Meyer, Gale Brightwell, Richard Kline, D.o. UlaetoAbstract:PCR assays that can identify the presence of variola virus (VARV) sequences in an unknown DNA sample were developed using principles established for the amplification refractory mutation system (ARMS). The assay's specificity utilised unique single nucleotide polymorphisms (SNP) identified among Orthopoxvirus (OPV) orthologs of the vaccinia virus Copenhagen strain A13L and A36R genes. When a variola virus specific primer was used with a consensus primer in an ARMS assay with different Orthopoxvirus genomes, a PCR product was only amplified from variola virus DNA. Incorporating a second consensus primer into the assay produced a multiplex PCR that provided Orthopoxvirus generic and variola-specific products with variola virus DNA. We tested two single nucleotide polymorphisms with a panel of 43 variola virus strains, collected over 40 years from countries across the world, and have shown that they provide reliable markers for variola virus identification. The variola virus specific primers did not produce amplicons with either assay format when tested with 50 other Orthopoxvirus DNA samples. Our analysis shows that these two polymorphisms were conserved in variola virus genomes and provide a reliable signature of Orthopoxvirus species identification.
Hermann Meyer - One of the best experts on this subject based on the ideXlab platform.
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Genus Orthopoxvirus: Monkeypox virus
Poxviruses, 2007Co-Authors: Sandra Essbauer, Hermann MeyerAbstract:Monkeypox virus is an Orthopoxvirus that is genetically distinct from other members of the genus, including Variola virus, Vaccinia virus, Ectromelia virus, Camelpox virus, and Cowpox virus. It was first identified as the cause of a pox-like illness in captive monkeys in 1958. In the 1970s, human infections occurred in Central and Western Africa clinically indistinguishable from smallpox. In contrast with Variola virus, however, Monkeypox virus has a wide range of hosts, which has allowed it to maintain a reservoir in wild animals. Human monkeypox was first recognized outside Africa in 2003 during an outbreak in the US that was traced to monkeypox virus-infected rodents imported from West Africa. Today, monkeypox is regarded as the most important Orthopoxvirus infection in human beings since the eradication of smallpox. There is currently no proven treatment for human monkeypox, and its potential as an agent of bioterrorism is discussed.
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Amplification refractory mutation system PCR assays for the detection of variola and Orthopoxvirus
Journal of virological methods, 2004Co-Authors: David Pulford, Inger K Damon, Hermann Meyer, Gale Brightwell, Richard Kline, D.o. UlaetoAbstract:PCR assays that can identify the presence of variola virus (VARV) sequences in an unknown DNA sample were developed using principles established for the amplification refractory mutation system (ARMS). The assay's specificity utilised unique single nucleotide polymorphisms (SNP) identified among Orthopoxvirus (OPV) orthologs of the vaccinia virus Copenhagen strain A13L and A36R genes. When a variola virus specific primer was used with a consensus primer in an ARMS assay with different Orthopoxvirus genomes, a PCR product was only amplified from variola virus DNA. Incorporating a second consensus primer into the assay produced a multiplex PCR that provided Orthopoxvirus generic and variola-specific products with variola virus DNA. We tested two single nucleotide polymorphisms with a panel of 43 variola virus strains, collected over 40 years from countries across the world, and have shown that they provide reliable markers for variola virus identification. The variola virus specific primers did not produce amplicons with either assay format when tested with 50 other Orthopoxvirus DNA samples. Our analysis shows that these two polymorphisms were conserved in variola virus genomes and provide a reliable signature of Orthopoxvirus species identification.
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Orthopoxvirus diagnostics.
Methods in molecular biology (Clifton N.J.), 2004Co-Authors: Hermann Meyer, Inger K Damon, Joseph J EspositoAbstract:Biologic and antigenic properties are often useful for identifying and differentiating Orthopoxviruses (OPV). However, polymerase chain reaction (PCR) amplification, with either restriction cleavage or sequencing of amplicons, has been gaining credibility as a more rapid, specific, sensitive, and often cost-saving technique for research and diagnostic laboratories. This chapter is consolidated using prior research papers from our laboratories with three different methods that should be suitable for the preparation of Orthopoxvirus DNA from various sources (e.g., clinical specimens or cell cultures) and four different methods for PCR that should be useful for investigating Orthopoxvirus species and strains.
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Sequence alterations within and downstream of the A-type inclusion protein genes allow differentiation of Orthopoxvirus species by polymerase chain reaction.
Journal of General Virology, 1994Co-Authors: Hermann Meyer, Martin Pfeffer, Hanns-joachim RzihaAbstract:A PCR protocol was established that not only allows the detection of, but also the differentiation of species of the genus Orthopoxvirus. This assay was accomplished by the selection of oligonucleotides located within the gene that encodes the A-type inclusion protein of cowpox virus. The primer pair flanked a region exhibiting distinct and specific DNA deletions in the corresponding sequences of vaccinia, mousepox, monkeypox and camelpox virus. For this reason, PCR resulted in DNA fragments of different sizes. The presented PCR protocol, combined with BglII restriction digests, allowed the unequivocal assignment of 42 Orthopoxvirus (OPV) strains and isolates to the correct OPV species. The resulting classification corresponded exactly with known biological data for the OPV strains investigated. Furthermore, 13 out of 22 cowpox virus isolates could be subtyped by the presence or absence of a small BglII fragment. DNA sequencing showed that the lack of this BglII fragment was caused by a deletion of 72 nucleotides.
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Differentiation of species of the genus Orthopoxvirus in a dot blot assay using digoxigenin-labeled DNA-probes.
Veterinary microbiology, 1993Co-Authors: Hermann Meyer, Nikolaus Osterrieder, Martin PfefferAbstract:A dot blot assay using five different digoxigenin-labeled probes was established for specific detection and differentiation of four species belonging to the genus Orthopoxvirus. As little as 20 pg Orthopoxvirus DNA can be detected, corresponding to approximately 8×104 DNA molecules. A total of 37 Orthopoxvirus strains and isolates of different origin were investigated and could be assigned to the species vaccina, cowpox, camelpox, and mousepox virus. These finding agree with their identification by biological means. Additionally, a simple procedure to isolate Orthopoxvirus DNA directly from scab material was developed. This allows a fast classification without isolating the virus.
Sergei N. Shchelkunov - One of the best experts on this subject based on the ideXlab platform.
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Comparing New-Generation Candidate Vaccines against Human Orthopoxvirus Infections.
Acta naturae, 2017Co-Authors: R. A. Maksyutov, S. N. Yakubitskyi, I. V. Kolosova, Sergei N. ShchelkunovAbstract:The lack of immunity to the variola virus in the population, increasingly more frequent cases of human Orthopoxvirus infection, and increased risk of the use of the variola virus (VARV) as a bioterrorism agent call for the development of modern, safe vaccines against Orthopoxvirus infections. We previously developed a polyvalent DNA vaccine based on five VARV antigens and an attenuated variant of the vaccinia virus (VACV) with targeted deletion of six genes (VACΔ6). Independent experiments demonstrated that triple immunization with a DNA vaccine and double immunization with VACΔ6 provide protection to mice against a lethal dose (10 LD50) of the ectromelia virus (ECTV), which is highly pathogenic for mice. The present work was aimed at comparing the immunity to smallpox generated by various immunization protocols using the DNA vaccine and VACΔ6. It has been established that immunization of mice with a polyvalent DNA vaccine, followed by boosting with recombinant VACΔ6, as well as double immunization with VACΔ6, induces production of VACV-neutralizing antibodies and provides protection to mice against a 150 LD50 dose of ECTV. The proposed immunization protocols can be used to develop safe vaccination strategies against smallpox and other human Orthopoxvirus infections.
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An Increasing Danger of Zoonotic Orthopoxvirus Infections
PLoS pathogens, 2013Co-Authors: Sergei N. ShchelkunovAbstract:On May 8, 1980, the World Health Assembly at its 33rd session solemnly declared that the world and all its peoples had won freedom from smallpox and recommended ceasing the vaccination of the population against smallpox. Currently, a larger part of the world population has no immunity not only against smallpox but also against other zoonotic Orthopoxvirus infections. Recently, recorded outbreaks of Orthopoxvirus diseases not only of domestic animals but also of humans have become more frequent. All this indicates a new situation in the ecology and evolution of zoonotic Orthopoxviruses. Analysis of state-of-the-art data on the phylogenetic relationships, ecology, and host range of Orthopoxviruses—etiological agents of smallpox (variola virus, VARV), monkeypox (MPXV), cowpox (CPXV), vaccinia (VACV), and camelpox (CMLV)—as well as the patterns of their evolution suggests that a VARV-like virus could emerge in the course of natural evolution of modern zoonotic Orthopoxviruses. Thus, there is an insistent need for organization of the international control over the outbreaks of zoonotic Orthopoxvirus infections in various countries to provide a rapid response and prevent them from developing into epidemics.
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Species-specific differences in organization of Orthopoxvirus kelch-like proteins.
Virus genes, 2002Co-Authors: Sergei N. Shchelkunov, A. V. Totmenin, Irina KolosovaAbstract:Organization of Orthopoxvirus proteins of the kelch superfamily and their genes were analyzed and compared. Complete genomic sequences of variola (VAR), monkeypox (MPV), vaccinia (VAC), and species-specific regions of cowpox (CPV) viruses were used in the work. Despite the multiplicity of kelch-like proteins in Orthopoxviruses, their function is still vague. It has been discovered that the genes of Orthopoxvirus kelch-like proteins are localized only to the terminal variable regions of the genome and display species-specific differences in the lengths of the proteins they potentially encode. All the genes belonging to kelch superfamily in the genome of VAR, which has the only host–the man, are mutationally destroyed. However, CPV, displaying the widest host range among Orthopoxviruses, encode the most numerous set of kelch-like proteins. Weak homologies between kelch-like proteins of one virus were demonstrated as well as high homologies between isologues of different Orthopoxvirus species. The comparison performed suggest that CPV virus is most ancient and may be considered as the ancestor of other Orthopoxviruses pathogenic for humans.
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Species-specific differences in the structure of Orthopoxvirus complement-binding protein
Virus Research, 2001Co-Authors: E. A. Uvarova, Sergei N. ShchelkunovAbstract:Vaccinia virus complement-binding protein (VCP) is secreted from the cells infected with the virus and controls the complement activation reactions. This protein contains four short consensus repeats (SCR), typical of the protein family of complement activation regulators. Organization of the VCP genes/proteins of Orthopoxviruses-monkeypox (MPV), variola, cowpox and vaccinia viruses-and their cellular homologues (DAF and C4BP) were studied comparatively. For this purpose, VCP genes of three MPV strains were sequenced. VCP gene sequences of other human-pathogenic Orthopoxvirus species and strains determined earlier were involved in the analysis. It has been demonstrated that a premature termination of the MPV VCP open reading frame results in a truncated protein sequence carrying a deletion of the C-terminal SCR4. This is an essential distinction of MPV from other Orthopoxvirus species.
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Expression of Orthopoxvirus DNA sequences in Escherichia coli cells
Molekuliarnaia biologiia, 1992Co-Authors: Sergei N. ShchelkunovAbstract:We observed the expression of recombinant plasmids genes containing ectromelia virus DNA fragments in E. coli minicells. Using plasmids with vaccinia or ectromelia viruses DNA fragments inserted upstream of lacZ gene we showed that certain Orthopoxvirus genome fragments carry out a promoter-like function in bacterial cells.
Jay W Hooper - One of the best experts on this subject based on the ideXlab platform.
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side by side comparison of gene based smallpox vaccine with mva in nonhuman primates
PLOS ONE, 2012Co-Authors: Joseph W Golden, Matthew Josleyn, Eric M Mucker, Chienfu Hung, Peter T Loudon, Jay W HooperAbstract:Orthopoxviruses remain a threat as biological weapons and zoonoses. The licensed live-virus vaccine is associated with serious health risks, making its general usage unacceptable. Attenuated vaccines are being developed as alternatives, the most advanced of which is modified-vaccinia virus Ankara (MVA). We previously developed a gene-based vaccine, termed 4pox, which targets four Orthopoxvirus antigens, A33, B5, A27 and L1. This vaccine protects mice and non-human primates from lethal Orthopoxvirus disease. Here, we investigated the capacity of the molecular adjuvants GM-CSF and Escherichia coli heat-labile enterotoxin (LT) to enhance the efficacy of the 4pox gene-based vaccine. Both adjuvants significantly increased protective antibody responses in mice. We directly compared the 4pox plus LT vaccine against MVA in a monkeypox virus (MPXV) nonhuman primate (NHP) challenge model. NHPs were vaccinated twice with MVA by intramuscular injection or the 4pox/LT vaccine delivered using a disposable gene gun device. As a positive control, one NHP was vaccinated with ACAM2000. NHPs vaccinated with each vaccine developed anti-Orthopoxvirus antibody responses, including those against the 4pox antigens. After MPXV intravenous challenge, all control NHPs developed severe disease, while the ACAM2000 vaccinated animal was well protected. All NHPs vaccinated with MVA were protected from lethality, but three of five developed severe disease and all animals shed virus. All five NHPs vaccinated with 4pox/LT survived and only one developed severe disease. None of the 4pox/LT-vaccinated animals shed virus. Our findings show, for the first time, that a subunit Orthopoxvirus vaccine delivered by the same schedule can provide a degree of protection at least as high as that of MVA.
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the strategic use of novel smallpox vaccines in the post eradication world
Expert Review of Vaccines, 2011Co-Authors: Joseph W Golden, Jay W HooperAbstract:We still face a threat of Orthopoxviruses in the form of biological weapons and emerging zoonoses. Therefore, there is a need to maintain a comprehensive defense strategy to counter the low-probability, high-impact threat of smallpox, as well as the ongoing threat of naturally occurring Orthopoxvirus disease. The currently licensed live-virus smallpox vaccine ACAM2000 is effective, but associated with serious and even life-threatening adverse events. The health threat posed by this vaccine, and other previously licensed vaccines, has prevented many first responders, and even many in the military, from receiving a vaccine against smallpox. At the same time, global immunity produced during the smallpox eradication campaign is waning. Here, we review novel subunit/component vaccines and how they might play roles in unconventional strategies to defend against emerging Orthopoxvirus diseases throughout the world and against smallpox used as a weapon of mass destruction.
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heterogeneity in the a33 protein impacts the cross protective efficacy of a candidate smallpox dna vaccine
Virology, 2008Co-Authors: Joseph W Golden, Jay W HooperAbstract:We previously developed a gene-based vaccine, termed 4pox, which targets four Orthopoxvirus proteins (A33, L1, B5, and A27). Because any subunit Orthopoxvirus vaccine must protect against multiple species of Orthopoxviruses, we are interested in understanding the cross-protective potential of our 4pox vaccine target immunogens. In our current studies, we focused on the A33 immunogen. We found one monoclonal antibody against A33, MAb-1G10, which could not bind the monkeypox virus A33 ortholog, A35. MAb-1G10 binding could be rescued if A35 amino acids 118 and 120 were substituted with those from A33. MAb-1G10 has been shown to protect mice from VACV challenge, thus our findings indicated a protective epitope differs among Orthopoxviruses. Accordingly, we tested the cross-protective efficacy of a DNA vaccine consisting of A35R against VACV challenge and compared it to vaccination with A33R DNA. Mice vaccinated with A35R had greater mortality and more weight loss compared to those vaccinated with A33R. These findings demonstrate that despite high homology between A33R orthologs, amino acid differences can impact cross-protection. Furthermore, our results caution that adequate cross-protection by any pan-Orthopoxvirus subunit vaccine will require not only careful evaluation of cross-protective immunity, but also of targeting of multiple Orthopoxvirus immunogens.
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smallpox dna vaccine protects nonhuman primates against lethal monkeypox
Journal of Virology, 2004Co-Authors: Jay W Hooper, E A Thompson, C Wilhelmsen, Michael A Zimmerman, Ait M Ichou, S E Steffen, Connie S Schmaljohn, Alan L Schmaljohn, Peter B. JahrlingAbstract:Two decades after a worldwide vaccination campaign was used to successfully eradicate naturally occurring smallpox, the threat of bioterrorism has led to renewed vaccination programs. In addition, sporadic outbreaks of human monkeypox in Africa and a recent outbreak of human monkeypox in the U.S. have made it clear that naturally occurring zoonotic Orthopoxvirus diseases remain a public health concern. Much of the threat posed by Orthopoxviruses could be eliminated by vaccination; however, because the smallpox vaccine is a live Orthopoxvirus vaccine (vaccinia virus) administered to the skin, the vaccine itself can pose a serious health risk. Here, we demonstrate that rhesus macaques vaccinated with a DNA vaccine consisting of four vaccinia virus genes (L1R, A27L, A33R, and B5R) were protected from severe disease after an otherwise lethal challenge with monkeypox virus. Animals vaccinated with a single gene (L1R) which encodes a target of neutralizing antibodies developed severe disease but survived. This is the first demonstration that a subunit vaccine approach to smallpox-monkeypox immunization is feasible.
