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Poxviruses are among the largest and most complex viruses known. Vaccinia virus, the prototype of the family Poxviridae, has been studied much more than myxoma virus. The aim of this work was to have a better knowledge about myxom...
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Poxviruses are among the largest and most complex viruses known. Vaccinia virus, the prototype of the family Poxviridae, has been studied much more than myxoma virus. The aim of this work was to have a better knowledge about myxoma virus morphogenesis. The characterization of the main stages of MV morphogenesis was achieved by ultrastructural and immunological analysis. Specific antibodies were raised against M022L and M071L, two envelope proteins of extracellular enveloped virus and intracellular mature virus, respectively. The main stages of assembly were similar to those seen with other poxviruses, and the duration of the whole replication cycle was estimated to be around 16 h, longer than what was described for vaccinia virus. Morphological changes of infected cells were associated with the development of long cellular projections and enlarged microvilli. Intracellular enveloped viruses are associated with the cytoskeleton to move through the cell. Unlike earlier studies, as many cell-associated enveloped viruses as intracellular enveloped viruses were observed in relation with specialized microvilli, although these structures were rarely noticed. Finally, an unusual spreading process was observed, which uses cytoplasmic corridors.
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Myxomatosis is a highly infectious viral disease of rabbits. Myxoma virus (MYXV) is not pathogenic to other animal species except for rabbits and hares. In Poland, outbreaks of myxomatosis mainly occur on small-scale size rabbit f...
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Myxomatosis is a highly infectious viral disease of rabbits. Myxoma virus (MYXV) is not pathogenic to other animal species except for rabbits and hares. In Poland, outbreaks of myxomatosis mainly occur on small-scale size rabbit farms in which specific immunoprophylaxis is not carried out. A typical nodular form of the disease is characterized by swelling and large myxomas over the whole body as well as by lung infection which is associated with atypical myxomatosis. However, differences in the virulence of MYXV strains are observed. They arise from a better adaptation of the virus to the rabbit host and they may also be related to the modulation of cellular response by infected animals. In fact, the changes observed in the MYXV genome do not result in the emergence of other novel virus strains than those currently circulating in the rabbit population. In addition, all previously detected strains are characterized by high phylogenetic relatedness.
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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 stra...
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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.
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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 stra...
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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.
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The myxoma virus (MYXV) causes severe infections in European rabbits that may reach mortality rates up to 100% depending on the viral strain. The typical symptoms and lesions induced by the virus are usually enough to permit the c...
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The myxoma virus (MYXV) causes severe infections in European rabbits that may reach mortality rates up to 100% depending on the viral strain. The typical symptoms and lesions induced by the virus are usually enough to permit the correct clinical diagnosis. However, in peracute forms the infection may be accompanied by unspecific symptoms. Sudden death may also occur without evident clinical signs of myxomatosis. Likewise, a clinical diagnosis of atypical forms of myxomatosis (amyxomatous) is often complicated and delayed due to the scarceness of skin lesions. As the disease control often depends on an early and unequivocal diagnosis of MYXV, laboratorial methods play a relevant role in the confirmation of MYXV infection. This study describes the development and validation of a novel, high accurate real time polymerase chain reaction assay (rtPCR) for the detection of MYXV. Primers were designed to amplify a 125-bp within the gene M000.5L/R, which is duplicated in the termini of the genome and is unique among Leporipoxvirus. The assay was negative for SFV and other poxviruses and was able to detect 2.6 copies of MYXV DNA proving the effectiveness, specificity and sensitivity of this diagnosis tool. The rtPCR has been applied successfully in INIAV laboratory for routine diagnosis of myxomatosis since 2005.
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Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replica...
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Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replication-competent viruses to selectively infect and destroy cancerous cells while sparing normal cells and tissues. Clinical and/or preclinical studies on oncolytic viruses have revealed that the candidate viruses being tested in trials are remarkably safe and offer potential for treating many classes of currently incurable cancers. Among these candidates are vaccinia and myxoma viruses, which belong to the family Poxviridae and possess promising oncolytic features. This article describes poxviruses that are being developed for oncolytic virotherapy and summarizes the outcomes of both clinical and preclinical studies. Additionally, studies demonstrating superior efficacy when poxvirus oncolytic virotherapy is combined with conventional therapies are described.
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Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replica...
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Current standard treatments of cancer can prolong survival of many cancer patients but usually do not effectively cure the disease. Oncolytic virotherapy is an emerging therapeutic for the treatment of cancer that exploits replication-competent viruses to selectively infect and destroy cancerous cells while sparing normal cells and tissues. Clinical and/or preclinical studies on oncolytic viruses have revealed that the candidate viruses being tested in trials are remarkably safe and offer potential for treating many classes of currently incurable cancers. Among these candidates are vaccinia and myxoma viruses, which belong to the family Poxviridae and possess promising oncolytic features. This article describes poxviruses that are being developed for oncolytic virotherapy and summarizes the outcomes of both clinical and preclinical studies. Additionally, studies demonstrating superior efficacy when poxvirus oncolytic virotherapy is combined with conventional therapies are described.
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Oncolytic viruses are one of the most promising novel therapeutics for malignant cancers. They selectively infect and kill cancer cells while sparing the normal counterparts, expose cancer- specific antigens and activate the host ...
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Oncolytic viruses are one of the most promising novel therapeutics for malignant cancers. They selectively infect and kill cancer cells while sparing the normal counterparts, expose cancer- specific antigens and activate the host immune system against both viral and tumor determinants. Oncolytic viruses can be used as monotherapy or combined with existing cancer therapies to become more potent. Among the many types of oncolytic viruses that have been developed thus far, members of poxviruses are the most promising candidates against diverse cancer types. This review summarizes recent advances that are made with oncolytic myxoma virus (MYXV), a member of the Leporipoxvirus genus. Unlike other oncolytic viruses, MYXV infects only rabbits in nature and causes no harm to humans or any other non-leporid animals. However, MYXV can selectively infect and kill cancer cells originating from human, mouse and other host species. This selective cancer tropism and safety profile have led to the testing of MYXV in various types of preclinical cancer models. The next stage will be successful GMP manufacturing and clinical trials that will bring MYXV from bench to bedside for the treatment of currently intractable malignancies.
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Myxomatosis is an emergent disease in the Iberian hare, having been considered a rabbit disease for decades. Genome sequencing of the strains obtained from Iberian hares with myxomatosis showed these to be distinct from the classi...
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Myxomatosis is an emergent disease in the Iberian hare, having been considered a rabbit disease for decades. Genome sequencing of the strains obtained from Iberian hares with myxomatosis showed these to be distinct from the classical ones that circulated in rabbits since the virus introduction in Europe, in 1952. The main genomic difference in this natural recombinant hare myxoma virus (ha-MYXV) is the presence of an additional 2.8 kb region disrupting the M009L gene and adding a set of genes homologous to the myxoma virus (MYXV) genes M060R, M061R, M064R, M065R and M066R originated in Poxviruses. After the emergence of this recombinant virus (ha-MYXV) in hares, in the summer of 2019, the ha-MYXV was not detected in rabbit surveys, suggesting an apparent species segregation with the MYXV classic strains persistently circulating in rabbits. Recently, a group of six unvaccinated European rabbits (Oryctolagus cuniculus cuniculus) from a backyard rabbitry in South Portugal developed signs of myxomatosis (anorexia, dyspnoea, oedema of eyelids, head, ears, external genitals and anus, and skin myxomas in the base of the ears). Five of them died within 24-48 hr of symptom onset. Molecular analysis revealed that only the recombinant MYXV was present. This is the first documented report of a recombinant hare myxoma virus in farm rabbits associated with high mortality, which increases the concern for the future of both the Iberian hare and wild rabbits and questions the safety of the rabbit industry. This highlights the urgent need to evaluate the efficacy of available vaccines against this new MYXV.
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Multiple myeloma (MM) is a hematological malignancy of plasma cells that remains incurable despite significant progress with myeloablative regimens and autologous stem cell transplantation for eligible patients and, more recently ...
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Multiple myeloma (MM) is a hematological malignancy of plasma cells that remains incurable despite significant progress with myeloablative regimens and autologous stem cell transplantation for eligible patients and, more recently with T cell redirected immunotherapy. Recently, we reported that ex vivo virotherapy with oncolytic myxoma virus (MYXV) improved MM-free survival in an autologous-transplant Balb/c mouse model. Here, we tested the Vk*MYC transplantable C57BL/6 mouse MM model that more closely recapitulates human disease. In vitro, the murine bortezomib-resistant Vk12598 cell line is fully susceptible to MYXV infection. In vivo results demonstrate: (i) autologous bone marrow (BM) leukocytes armed ex vivo with MYXV exhibit moderate therapeutic effects against MM cells pre-seeded into recipient mice; (ii) Cyclophosphamide in combination with BM/MYXV delays the onset of myeloma in mice seeded with Vk12598 cells; (iii) BM/MYXV synergizes with the Smac-mimetics LCL161 and with immune checkpoint inhibitor α-PD-1 to control the progression of established MM in vivo, resulting in significant improvement of survival rates and decreased of tumor burden; (iv) Survivor mice from (ii) and (iii), when re-challenged with fresh Vk12598 cells, developed acquired anti-MM immunity. These results highlight the utility of autologous BM grafts armed ex vivo with oncolytic MYXV alone or in combination with chemotherapy/immunotherapy to treat drug-resistant MM in vivo.
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