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2.
Transbound Emerg Dis ; 66(6): 2204-2208, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31293076

RESUMO

Myxomatosis is an infectious disease caused by myxoma virus (MYXV; genus Leporipoxvirus), which affects the European wild rabbit (Oryctolagus cuniculus) and sporadically brown hares (Lepus europaeus). Here, we describe the first outbreak of myxomatosis in Iberian hares (Lepus granatensis). Between mid-July and the end of September 2018, around 530 dead animals were detected in Iberian hare populations in southern Spain. The apparent mean mortality rate was 56.7%, and the estimated mean case fatality rate was 69.2%. Histopathological and molecular results confirmed MYXV infections in all hares analysed. To the authors' knowledge, this is the first myxomatosis outbreak causing a high mortality in hares and the first detailed characterization of a myxomatosis outbreak in the Iberian hare. The absence of cases in sympatric wild rabbits suggests differences in the susceptibility between both lagomorph species to the virus strain implicated in the outbreak. After the first case, the number of affected areas increased sharply affecting most of the Iberian Peninsula where the Iberian hare is present. Further studies are required to elucidate the origin of the implicated MYXV strain as well as to assess the impact of this outbreak on the Iberian hare populations.


Assuntos
Surtos de Doenças/veterinária , Lebres/virologia , Infecções por Poxviridae/epidemiologia , Infecções por Poxviridae/veterinária , Animais , Epiderme/patologia , Epiderme/virologia , Pulmão/patologia , Pulmão/virologia , Myxoma virus , Coelhos , Espanha/epidemiologia
3.
Transbound Emerg Dis ; 66(6): 2218-2226, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31322320

RESUMO

The study of myxoma virus (MYXV) infections in the European rabbit (Oryctolagus cuniculus) has produced one of the most accepted host-pathogen evolutionary models. To date, myxomatosis has been limited to the European rabbit with sporadic reports in hares. However, reports of widespread mortalities in the Iberian hare (Lepus granatensis) with myxomatosis-like clinical signs indicate a potential species jump has occurred. The presence of MYXV DNA was confirmed by PCR in 244 samples received from regional veterinary services, animal health laboratories, hunters or rangers over a 5-month period. PCR analysis of 4 MYXV positive hare samples revealed a 2.8 kb insertion located within the M009 gene with respect to MYXV. The presence of this insertion was subsequently confirmed in 20 samples from 18 Spanish provinces. Sanger sequencing and subsequent analysis show that the insert contained 4 ORFs which are phylogenetically related to MYXV genes M060, M061, M064 and M065. The complete MYXV genome from hare tissue was sequenced using Ion torrent next-generation technology and a summary of the data presented here. With the exception of the inserted region, the virus genome had no large scale modifications and 110 mutations with respect to the MYXV reference strain Lausanne were observed. The next phase in the evolution of MYXV has taken place as a host species jump from the European rabbit to the Iberian hare an occurrence which could have important effects on this naïve population.


Assuntos
Lebres/virologia , Myxoma virus/genética , Infecções por Poxviridae/virologia , Animais , DNA Viral/genética , Genoma Viral , Mutagênese Insercional , Filogenia , Reação em Cadeia da Polimerase , Infecções por Poxviridae/veterinária , Coelhos , Espanha , Sequenciamento Completo do Genoma
4.
J Virol Methods ; 272: 113709, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31351983

RESUMO

Recognition of myxomatosis is usually based on clinical symptoms, but amyxomatous cases of the disease require the use of laboratory methods. Nowadays PCR assays are routinely employed for detection of MYXV DNA, but none of them have had their diagnostic usefulness conclusively confirmed through validation. The aim of the study was the development and validation of a PCR with an internal amplification control (IAC) for intravital and postmortem detection of viral DNA of myxoma virus. To avoid false negative results a chimeric internal amplification control (IAC) was prepared and incorporated into the PCR and amplified by the same primer set as the target DNA (M071L). The optimal concentration of particular ingredients in the PCR mixture (including IAC concentration and volume of DNA sample) was determined. To minimize the risk of amplicon carry-over contamination, uracil N-glycosylase was added to the reaction. Before proper validation the robustness of the IAC-PCR was verified. Validation of the method encompassed the following parameters: the analytical and diagnostic specificity (ASp, DSp) and sensitivity (ASe, DSe) of the assay, repeatability, and intra-laboratory reproducibility. The assay LOD was established at 2 TCIU of the virus particles/0.2 ml tissue homogenate with a 100% capacity to detect different MYXV strains (ASp). The method was characterized by good DSp of 0.955 (0.839-0.999 CI) and DSe of 0.976 (0.914-1.00 CI). In addition, it was repeatable and reproducible and confirmed its suitability for the detection of MYXV in clinical material. The IAC-PCR developed meets OIE validation requirements for virological methods and can be used in diagnostic or epidemiological studies of rabbit myxomatosis.


Assuntos
DNA Viral/isolamento & purificação , Myxoma virus/genética , Myxoma virus/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Animais , Mixomatose Infecciosa/diagnóstico , Mixomatose Infecciosa/epidemiologia , Mixomatose Infecciosa/virologia , Polônia/epidemiologia , Coelhos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
J Biol Chem ; 294(21): 8480-8489, 2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-30940649

RESUMO

Among the repertoire of immunoregulatory proteins encoded by myxoma virus, M013 is a viral homologue of the viral pyrin domain-only protein (vPOP) family. In myeloid cells, M013 protein has been shown to inhibit both the inflammasome and NF-κB signaling pathways by direct binding to ASC1 and NF-κB1, respectively. In this study, a three-dimensional homology model of the M013 pyrin domain (PYD) was built based on similarities to known PYD structures. A distinctive feature of the deduced surface electrostatic map of the M013 PYD is the presence of a negatively region consisting of numerous aspartate and glutamate residues in close proximity. Single-site mutations of aspartate and glutamate residues reveal their role in interactions with ASC-1. The biological significance of charge complementarity in the M013-ASC-1 interaction was further confirmed by functional assays of caspase-1 activation and subsequent secretion of cytokines. M013 also has a unique 33-residue C-terminal tail that follows the N-terminal PYD, and it is enriched in positively charged residues. Deletion of the tail of M013 significantly inhibited the interactions between M013 and NF-κB1, thus compromising the ability of the viral protein to suppress the secretion of pro-inflammatory cytokines. These results demonstrate that vPOP M013 exploits distinct structural motifs to regulate both the inflammasome and NF-κB pathways.


Assuntos
Myxoma virus , NF-kappa B/imunologia , Transdução de Sinais/imunologia , Proteínas Virais , Motivos de Aminoácidos , Substituição de Aminoácidos , Caspase 1/genética , Caspase 1/imunologia , Células HeLa , Humanos , Inflamassomos/genética , Mutagênese Sítio-Dirigida , Mutação de Sentido Incorreto , Myxoma virus/química , Myxoma virus/genética , Myxoma virus/imunologia , NF-kappa B/genética , Domínios Proteicos , Transdução de Sinais/genética , Células THP-1 , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/imunologia
6.
J Clin Invest ; 129(6): 2279-2292, 2019 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-31033480

RESUMO

Oncolytic virotherapy has been proposed as an ablative and immunostimulatory treatment strategy for solid tumors that are resistant to immunotherapy alone; however, there is a need to optimize host immune activation using preclinical immunocompetent models in previously untested common adult tumors. We studied a modified oncolytic myxoma virus (MYXV) that shows high efficiency for tumor-specific cytotoxicity in small-cell lung cancer (SCLC), a neuroendocrine carcinoma with high mortality and modest response rates to immune checkpoint inhibitors. Using an immunocompetent SCLC mouse model, we demonstrated the safety of intrapulmonary MYXV delivery with efficient tumor-specific viral replication and cytotoxicity associated with induction of immune cell infiltration. We observed increased SCLC survival following intrapulmonary MYXV that was enhanced by combined low-dose cisplatin. We also tested intratumoral MYXV delivery and observed immune cell infiltration associated with tumor necrosis and growth inhibition in syngeneic murine allograft tumors. Freshly collected primary human SCLC tumor cells were permissive to MYXV and intratumoral delivery into patient-derived xenografts resulted in extensive tumor necrosis. We confirmed MYXV cytotoxicity in classic and variant SCLC subtypes as well as cisplatin-resistant cells. Data from 26 SCLC human patients showed negligible immune cell infiltration, supporting testing MYXV as an ablative and immune-enhancing therapy.


Assuntos
Cisplatino/farmacologia , Neoplasias Pulmonares/terapia , Myxoma virus , Terapia Viral Oncolítica , Vírus Oncolíticos , Carcinoma de Pequenas Células do Pulmão/terapia , Animais , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , Neoplasias Pulmonares/patologia , Camundongos , Camundongos Knockout , Carcinoma de Pequenas Células do Pulmão/genética , Carcinoma de Pequenas Células do Pulmão/imunologia , Carcinoma de Pequenas Células do Pulmão/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Expert Opin Biol Ther ; 19(6): 561-573, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30919708

RESUMO

INTRODUCTION: Over the last decade, advances in biological therapies have resulted in remarkable clinical responses for the treatment of some previously incurable cancers. Oncolytic virotherapy is one of these promising novel strategies for cancer therapy. A successful oncolytic virus promotes tumor cell oncolysis and elicits a robust long-term anti-tumor immunity. AREAS COVERED: Oncolytic poxviruses (Vaccinia virus and Myxoma virus) demonstrated encouraging results in multiple pre-clinical tumor models and some clinical trials for the treatment of various cancers. This review summarizes the advances made on poxvirus oncolytic virotherapy in the last five years. EXPERT OPINION: Many challenges remain in poxvirus oncolytic virotherapy. Two key goals to achieve are enhancing the efficiency of viral delivery to tumor sites and overcoming local tumor immune-evasion. Additional efforts are necessary to explore the best combination of virotherapy with standard available treatments, particularly immunotherapies. By addressing these issues, this new modality will continue to improve as an adjunct biotherapy to treat malignant diseases.


Assuntos
Neoplasias/terapia , Terapia Viral Oncolítica , Poxviridae/genética , Quimioterapia Adjuvante , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Vetores Genéticos/uso terapêutico , Humanos , Imunoterapia Adotiva , Myxoma virus/genética , Linfócitos T/citologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Vírus Vaccinia/genética
8.
Science ; 363(6433): 1277-1278, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30898916
9.
Science ; 363(6433): 1319-1326, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30765607

RESUMO

In the 1950s the myxoma virus was released into European rabbit populations in Australia and Europe, decimating populations and resulting in the rapid evolution of resistance. We investigated the genetic basis of resistance by comparing the exomes of rabbits collected before and after the pandemic. We found a strong pattern of parallel evolution, with selection on standing genetic variation favoring the same alleles in Australia, France, and the United Kingdom. Many of these changes occurred in immunity-related genes, supporting a polygenic basis of resistance. We experimentally validated the role of several genes in viral replication and showed that selection acting on an interferon protein has increased the protein's antiviral effect.


Assuntos
Adaptação Biológica/genética , Imunidade Inata/genética , Myxoma virus/imunologia , Mixomatose Infecciosa/imunologia , Coelhos/genética , Coelhos/virologia , Alelos , Animais , Austrália , Evolução Molecular , França , Frequência do Gene , Variação Genética , Interferon alfa-2/genética , Interferon alfa-2/imunologia , Mixomatose Infecciosa/genética , Polimorfismo de Nucleotídeo Único , População , Coelhos/imunologia , Reino Unido
10.
J Virol ; 93(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30728252

RESUMO

Myxoma virus (MYXV) has been evolving in a novel host species-European rabbits-in Australia since 1950. Previous studies of viruses sampled from 1950 to 1999 revealed a remarkably clock-like evolutionary process across all Australian lineages of MYXV. Through an analysis of 49 newly generated MYXV genome sequences isolated in Australia between 2008 and 2017, we show that MYXV evolution in Australia can be characterized by three lineages, one of which exhibited a greatly elevated rate of evolutionary change and a dramatic breakdown of temporal structure. Phylogenetic analysis revealed that this apparently punctuated evolutionary event occurred between 1996 and 2012. The branch leading to the rapidly evolving lineage contained a relatively high number of nonsynonymous substitutions, and viruses in this lineage reversed a mutation found in the progenitor standard laboratory strain (SLS) and all previous sequences that disrupts the reading frame of the M005L/R gene. Analysis of genes encoding proteins involved in DNA synthesis or RNA transcription did not reveal any mutations likely to cause rapid evolution. Although there was some evidence for recombination across the MYXV phylogeny, this was not associated with the increase in the evolutionary rate. The period from 1996 to 2012 saw significant declines in wild rabbit numbers, due to the introduction of rabbit hemorrhagic disease and prolonged drought in southeastern Australia, followed by the partial recovery of populations. It is therefore possible that a rapidly changing environment for virus transmission changed the selection pressures faced by MYXV, altering the course and pace of virus evolution.IMPORTANCE The coevolution of myxoma virus (MYXV) and European rabbits in Australia is one of the most important natural experiments in evolutionary biology, providing insights into virus adaptation to new hosts and the evolution of virulence. Previous studies of MYXV evolution have also shown that the virus evolves both relatively rapidly and in a strongly clock-like manner. Using newly acquired MYXV genome sequences from Australia, we show that the virus has experienced a dramatic change in evolutionary behavior over the last 20 years, with a breakdown in clock-like structure, the appearance of a rapidly evolving virus lineage, and the accumulation of multiple nonsynonymous and indel mutations. We suggest that this punctuated evolutionary event may reflect a change in selection pressures as rabbit numbers declined following the introduction of rabbit hemorrhagic disease virus and drought in the geographic regions inhabited by rabbits.


Assuntos
Evolução Molecular , Genes Virais , Myxoma virus/genética , Fases de Leitura Aberta , Filogenia , Infecções por Poxviridae , Animais , Austrália , Infecções por Poxviridae/genética , Infecções por Poxviridae/veterinária , Coelhos , Fatores de Tempo , Proteínas Virais/genética , Sequenciamento Completo do Genoma
11.
Methods Mol Biol ; 1826: 73-86, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30194594

RESUMO

The serpin family of serine proteinase inhibitors plays key roles in the maintenance of mammalian homeostasis. Virus-encoded serpins disrupt the balance of mammalian proteases to facilitate virus replication in the infected host. DNA viruses, in particular members of the poxvirus family, have acquired multiple copies of the functional serpins which are essential for viral pathogenesis. Virus-encoded serpins have proven to be very effective inhibitors of host proteases and thus are very attractive candidate molecules as immunomodulatory drugs. With this chapter we explain approaches to identifying immune-modulating viral serpins.


Assuntos
Myxoma virus , Serpinas , Proteínas Virais , Animais , Linhagem Celular , Myxoma virus/genética , Myxoma virus/metabolismo , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Coelhos , Serpinas/genética , Serpinas/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismo
12.
Methods Mol Biol ; 1826: 237-254, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30194605

RESUMO

Adeno-associated virus (AAV) has become the preferred viral gene transfer platform for ocular gene therapy due to its known safety profile in human clinical trials. This viral vector has a 4.7 kbp (kilo base pair) carrying capacity (single-stranded DNA) and only retains the inverted terminal repeats (ITRs) from the original virus. Here we describe the design and testing of AAV vectors capable of delivering an anti-inflammatory serine protease inhibitor (serpin) derived from the myxoma virus. Myxoma is a rabbit species specific virus infection, a Leporipoxvirus. Myxomaviral proteins have been developed as therapeutic stand-alone immune-modulating proteins for inflammation-based disorders and the myxoma virus itself is under development as a viral oncolytic platform for cancer treatment. We fused the Serp2 gene with the GFP reporter gene through a self-cleaving peptide.


Assuntos
Dependovirus , Myxoma virus/genética , Transdução Genética/métodos , Proteínas Virais , Animais , Células HEK293 , Humanos , Coelhos , Proteínas Virais/biossíntese , Proteínas Virais/genética
13.
Methods Mol Biol ; 1826: 255-265, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30194606

RESUMO

Serine protease inhibitors, or serpins, function as central regulators for many vital processes in the mammalian body, maintaining homeostasis for clot formation and breakdown, immune responses, lung function, and hormone or central nervous system activity, among many others. When serine protease activity or serpin-mediated regulation becomes unbalanced or dysfunctional, then severe disease states and pathogenesis can ensue. With serpinopathies, genetic mutations lead to inactive serpins or protein aggregation with loss of function. With other disorders, such as sepsis, atherosclerosis, cancer, obesity, and the metabolic syndrome, the thrombotic and thrombolytic cascades and/or inflammatory responses become unbalanced, with excess bleeding and clotting and upregulation of adverse immune responses. Returning overall balance can be engineered through introduction of a beneficial serpin replacement as a therapeutic or through blockade of serpins that are detrimental. Several drugs have been developed and are currently in use and/or in development both to replace dysfunctional serpins and to block adverse effects induced by aberrant protease or serpin actions.With this chapter, we provide a general overview of the development of a virus-derived serpin, Serp-1, and serpin reactive center loop (RCL) peptides, as therapeutics. Serp-1 is a virus-derived serpin developed as a new class of immune modulator. We will use the development of Serp-1 as a general introduction to serpin-based drug development.


Assuntos
Desenvolvimento de Medicamentos , Fatores Imunológicos , Myxoma virus , Peptídeos , Serpinas , Proteínas Virais , Animais , Humanos , Fatores Imunológicos/química , Fatores Imunológicos/genética , Fatores Imunológicos/uso terapêutico , Myxoma virus/química , Myxoma virus/genética , Peptídeos/química , Peptídeos/genética , Peptídeos/uso terapêutico , Serpinas/química , Serpinas/genética , Serpinas/uso terapêutico , Proteínas Virais/química , Proteínas Virais/genética , Proteínas Virais/uso terapêutico
14.
J Anim Ecol ; 87(5): 1418-1428, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30133819

RESUMO

European rabbits (Oryctolagus cuniculus) have been exposed to rabbit haemorrhagic disease virus (RHDV) and myxoma virus (MYXV) in their native and invasive ranges for decades. Yet, the long-term effects of these viruses on rabbit population dynamics remain poorly understood. In this context, we analysed 17 years of detailed capture-mark-recapture data (2000-2016) from Turretfield, South Australia, using a probabilistic state-space hierarchical modelling framework to estimate rabbit survival and epidemiological dynamics. While RHDV infection and disease-induced death were most prominent during annual epidemics in winter and spring, we found evidence for continuous infection of susceptible individuals with RHDV throughout the year. RHDV-susceptible rabbits had, on average, 25% lower monthly survival rates compared to immune individuals, while the average monthly force of infection in winter and spring was ~38%. These combined to result in an average infection-induced mortality rate of 69% in winter and spring. Individuals susceptible to MYXV and immune to RHDV had similar survival probabilities to those having survived infections from both viruses, whereas individuals susceptible to both RHDV and MYXV had higher survival probabilities than those susceptible to RHDV and immune to MYXV. This suggests that MYXV may reduce the future survival rates of individuals that endure initial MYXV infection. There was no evidence for long-term changes in disease-induced mortality and infection rates for either RHDV or MYXV. We conclude that continuous, year-round virus perpetuation (and perhaps heterogeneity in modes of transmission and infectious doses during and after epidemics) acts to reduce the efficiency of RHDV and MYXV as biocontrol agents of rabbits in their invasive range. However, if virulence can be maintained as relatively constant through time, RHDV and MYXV will likely continue realizing strong benefits as biocontrol agents.


Assuntos
Infecções por Caliciviridae , Vírus da Doença Hemorrágica de Coelhos , Myxoma virus , Animais , Coelhos , Austrália do Sul , Virulência
15.
Viruses ; 10(8)2018 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-30060548

RESUMO

Many oncolytic viruses that are efficacious in murine cancer models are ineffective in humans. The outcomes of oncolytic virus treatment in dogs with spontaneous tumors may better predict human cancer response and improve treatment options for dogs with cancer. The objectives of this study were to evaluate the safety of treatment with myxoma virus lacking the serp2 gene (MYXVΔserp2) and determine its immunogenicity in dogs. To achieve these objectives, dogs with spontaneous soft tissue sarcomas were treated with MYXVΔserp2 intratumorally (n = 5) or post-operatively (n = 5). In dogs treated intratumorally, clinical scores were recorded and tumor biopsies and swabs (from the mouth and virus injection site) were analyzed for viral DNA at multiple time-points. In all dogs, blood, urine, and feces were frequently collected to evaluate organ function, virus distribution, and immune response. No detrimental effects of MYXVΔserp2 treatment were observed in any canine cancer patients. No clinically significant changes in complete blood profiles, serum chemistry analyses, or urinalyses were measured. Viral DNA was isolated from one tumor swab, but viral dissemination was not observed. Anti-MYXV antibodies were occasionally detected. These findings provide needed safety information to advance clinical trials using MYXVΔserp2 to treat patients with cancer.


Assuntos
Myxoma virus , Terapia Viral Oncolítica , Vírus Oncolíticos , Sarcoma/terapia , Sarcoma/veterinária , Animais , Linhagem Celular Tumoral , DNA Viral/sangue , DNA Viral/isolamento & purificação , DNA Viral/urina , Cães , Fezes/virologia , Terapia Viral Oncolítica/efeitos adversos , Proteínas Virais/genética
16.
J Virol ; 92(20)2018 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-30045995

RESUMO

High-throughput DNA sequencing enables the study of experimental evolution in near real time. Until now, mutants with deletions of nonessential host range genes were used in experimental evolution of vaccinia virus (VACV). Here, we guided the selection of adaptive mutations that enhanced the fitness of a hybrid virus in which an essential gene had been replaced with an ortholog from another poxvirus genus. Poxviruses encode a complete system for transcription, including RNA polymerase and stage-specific transcription factors. The abilities of orthologous intermediate transcription factors from other poxviruses to substitute for those of VACV, as determined by transfection assays, corresponded with the degree of amino acid identity. VACV in which the A8 or A23 intermediate transcription factor subunit gene was replaced by the myxoma (MYX) virus ortholog exhibited decreased replication. During three parallel serial passages of the hybrid virus with the MYXA8 gene, plaque sizes and virus yields increased. DNA sequencing of virus populations at passage 10 revealed high frequencies of five different single nucleotide mutations in the two largest RNA polymerase subunits, RPO147 and RPO132, and two different Kozak consensus sequence mutations predicted to increase translation of the MYXA8 mRNA. Surprisingly, there were no mutations within either intermediate transcription factor subunit. Based on homology with Saccharomyces cerevisiae RNA polymerase, the VACV mutations were predicted to be buried within the internal structure of the enzyme. By directly introducing single nucleotide substitutions into the genome of the original hybrid virus, we demonstrated that both RNA polymerase and translation-enhancing mutations increased virus replication independently.IMPORTANCE Previous studies demonstrated the experimental evolution of vaccinia virus (VACV) following deletion of a host range gene important for evasion of host immune defenses. We have extended experimental evolution to essential genes that cannot be deleted but could be replaced by a divergent orthologous gene from another poxvirus. Replacement of a VACV transcription factor gene with one from a distantly related poxvirus led to decreased fitness as evidenced by diminished replication. Serially passaging the hybrid virus at a low multiplicity of infection provided conditions for selection of adaptive mutations that improved replication. Notably, these included five independent mutations of the largest and second largest RNA polymerase subunits. This approach should be generally applicable for investigating adaptation to swapping of orthologous genes encoding additional essential proteins of poxviruses as well as other viruses.


Assuntos
RNA Polimerases Dirigidas por DNA/genética , Evolução Molecular , Mutação de Sentido Incorreto , Myxoma virus/enzimologia , Fatores de Transcrição/genética , Vírus Vaccinia/fisiologia , Replicação Viral , RNA Polimerases Dirigidas por DNA/metabolismo , Myxoma virus/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Seleção Genética , Inoculações Seriadas , Fatores de Transcrição/metabolismo , Vírus Vaccinia/genética , Vírus Vaccinia/crescimento & desenvolvimento , Carga Viral , Ensaio de Placa Viral
17.
Comp Med ; 68(4): 280-285, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30017020

RESUMO

Myxoma virus is a member of Leporipoxviridae whose tropism is tightly restricted to lagomorphs. In susceptible Oryctolagus rabbits, the virus causes a highly lethal disease known as myxomatosis, which begins as a localized infection but rapidly disseminates throughout the animal, leading to immune compromise, mucosal infections, multiorgan failure, and death. In a research setting, myxoma infection of susceptible Oryctolagus cuniculus rabbits is used as a model of poxviral disease progression and represents one of only a few means to study the pathogenesis of this viral family in a native host species. However, the rapid progression of myxomatosis makes accurate prediction of humane endpoints critical to limiting animal pain and distress and preventing death as an endpoint. Here we present case studies of myxomatosis at 2 institutions and offer a refined scoring system to reliably track the course of disease in susceptible rabbits infected with myxoma virus.


Assuntos
Bem-Estar do Animal , Myxoma virus , Infecções por Poxviridae/veterinária , Animais , Modelos Animais de Doenças , Suscetibilidade a Doenças , Feminino , Infecções por Poxviridae/patologia , Coelhos , Reprodutibilidade dos Testes , Projetos de Pesquisa , Virulência
18.
Bioessays ; 40(8): e1800050, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29869436

RESUMO

Cancer cells seem to exploit mechanisms that evolve as part of physiological tolerance, which is a complementary and often beneficial form of defense. The study of physiological systems of tolerance can therefore provide insights into the development of a state of host tolerance of cancer, and how to break it. Analysis of these models has the potential to improve our understanding of existing immunological therapeutic targets, and help to identify future targets and rational therapeutic combinations. The treatment of cancer with immune checkpoint inhibitors aims to reverse the progression to tolerance of cancer, and achieve an immunogenic, rather than tolerogenic, homeostasis. Broadening the efficacy and durability of checkpoint inhibitors focuses on reversing tolerance and stimulating immunogenicity in the cancer, host, and environment. Two examples of important physiological states of tolerance that may inform tolerance of cancer are microbial infection and placental reproduction. These states of tolerance result from bilateral shaping of host and non-self, akin to immunoediting in cancer, and offer reliable models to study the immune tolerance paradigm.


Assuntos
Interações Hospedeiro-Patógeno/imunologia , Tolerância Imunológica/fisiologia , Infecções/imunologia , Neoplasias/imunologia , Placenta/fisiologia , Aloenxertos/imunologia , Animais , Feminino , Humanos , Microbiota , Myxoma virus/patogenicidade , Infecções por Poxviridae/mortalidade , Gravidez , Microambiente Tumoral/imunologia
19.
J Wildl Dis ; 54(3): 544-547, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29667872

RESUMO

Digital media and digital search tools offer simple and effective means to monitor for pathogens and disease outbreaks in target organisms. Using tools such as Rich Site Summary feeds, and Google News and Google Scholar specific key word searches, international digital media were actively monitored from 2012 to 2016 for pathogens and disease outbreaks in the taxonomic order Lagomorpha, with a specific focus on the European rabbit ( Oryctolagus cuniculus). The primary objective was identifying pathogens for assessment as potential new biocontrol agents for Australia's pest populations of the European rabbit. A number of pathogens were detected in digital media reports. Additional benefits arose in the regular provision of case reports and research on myxomatosis and rabbit haemorrhagic disease virus that assisted with current research.


Assuntos
Infecções por Caliciviridae/veterinária , Surtos de Doenças/veterinária , Internet , Mixomatose Infecciosa/epidemiologia , Coelhos , Animais , Animais Selvagens , Austrália/epidemiologia , Infecções por Caliciviridae/epidemiologia , Vírus da Doença Hemorrágica de Coelhos , Myxoma virus , Vigilância da População
20.
J Virol ; 92(7)2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29343569

RESUMO

Poxviruses are large, DNA viruses whose protein capsid is surrounded by one or more lipid envelopes. Embedded into these lipid envelopes are three conserved viral proteins which are thought to mediate binding of virions to target cells. While the function of these proteins has been studied in vitro, their specific roles during the pathogenesis of poxviral disease remain largely unclear. Here we present data demonstrating that the putative chondroitin binding protein M083 from the leporipoxvirus myxoma virus is a significant virulence factor during infection of susceptible Oryctolagus rabbits. Removal of M083 results in a reduced capacity of virus to spread beyond the regional lymph nodes and completely eliminates infection-mediated mortality. In vitro, removal of M083 results in only minor intracellular replication defects but causes a significant reduction in the ability of myxoma virus to spread from infected epithelial cells onto primary lymphocytes. We hypothesize that the physiological role of M083 is therefore to mediate the spread of myxoma virus onto rabbit lymphocytes, allowing these cells to disseminate virus throughout infected rabbits.IMPORTANCE Poxviruses represent both a class of human pathogens and potential therapeutic agents for the treatment of human malignancy. Understanding the basic biology of these agents is therefore significant to human health in a variety of ways. While the mechanisms mediating poxviral binding have been well studied in vitro, how these mechanisms impact poxviral pathogenesis in vivo remains unclear. The current study advances our understanding of how poxviral binding impacts viral pathogenesis by demonstrating that the putative chondroitin binding protein M083 plays a critical role during the pathogenesis of myxoma virus in susceptible Oryctolagus rabbits by impacting viral dissemination through changes in the transfer of virions onto primary splenocytes.


Assuntos
Linfócitos/virologia , Myxoma virus , Proteínas Virais , Células A549 , Animais , Humanos , Linfócitos/metabolismo , Linfócitos/patologia , Myxoma virus/genética , Myxoma virus/metabolismo , Myxoma virus/patogenicidade , Coelhos , Proteínas Virais/genética , Proteínas Virais/metabolismo
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