08-25-2021-1146 - Vaccinia Virus Ankara - Laboratory-acquired infection is also possible, because VACV is extensively used in laboratory-based research in the study of virology, immunology, and vaccine development. Because VACV remains pathogenic to unvaccinated individuals, laboratory workers who handle VACV strains that are not highly attenuated must receive the appropriate vaccine.308 1930 1920 1890 1820 1794 1760 1646 1502 1492 1201 1180 1000 etc.

Vaccinia Virus

Vaccinia virus produces proteins that either antagonize kinases or bind to adaptor proteins in TLR signaling pathways, suppressing the activation of host cell transcription needed for antiviral responses.

From: Primer to the Immune Response (Second Edition), 2014 

• Neoplasm
• Recombinant
• Antigen
• Protein
• DNA
• Virus Infection
• Poxviridae
• Smallpox

• Vaccinia Virus

  G.L. Smith, in Encyclopedia of Virology (Third Edition), 2008

  Taxonomy

  Vaccinia virus is the most intensively studied species in the genus Orthopoxvirus of the family Poxviridae, and several VACV strains have been sequenced. The first strain sequenced was Copenhagen, which has been a reference for comparison with the sequences of additional VACV strains and other OPVs. Other commonly used, sequenced VACV strains are Western Reserve (WR), Lister (and derivatives LC16m0 and LC16m8), and MVA. All VACV strains cluster closely together phylogenetically, as do all other OPV species except for CPXV, where two strains (GRI-90 and Brighton Red) are more divergent and might eventually be considered as separate species. HSPV appears to be the OPV most closely related to VACV.

  VACCINIA VIRUS (POXVIRIDAE)

  Riccardo Wittek, in Encyclopedia of Virology (Second Edition), 1999

  Geographic and Seasonal Distribution

  Vaccinia virus is not associated with a naturally occurring disease in humans. The smallpox vaccine was extensively used worldwide but, after eradication of smallpox, vaccination was abandoned.

  Rabbitpox virus, a highly virulent vaccinia virus strain, has caused outbreaks of a lethal pox disease in colonies of laboratory rabbits in Utrecht and New York. Several outbreaks of buffalopox occurred in Maharashtra state in India, where buffaloes are used for milk production. The disease is caused by an orthopoxvirus which is closely related to vaccinia virus, but different enough to justify classification as a subspecies of vaccinia virus.

  How Does Vaccinia Virus Interfere With Interferon?

  Geoffrey L. Smith, ... Yongxu Lu, in Advances in Virus Research, 2018

  7 Summary

  VACV has acquired a remarkable arsenal of proteins that inhibit the production of IFNs, the binding of IFNs to their receptors, IFN-induced signaling, and the antiviral activity of ISGs. The existence of these VACV proteins provides not only evidence of the importance of the IFN system for protection against viruses but also illustrates how the IFN system functions. It is likely that additional VACV proteins that target the IFN system remain to be discovered and, equally, it is possible that VACV proteins that target the IFN system will lead to the discovery of additional cellular proteins that function in the IFN system. Viruses are wonderful tools for learning about innate immunity and cell biology and so, although VACV was used as a vaccine against a disease that was eradicated nearly 40 years ago, there are compelling reasons to continue to study it.

  Modified Vaccinia Virus Ankara

  A. Volz, G. Sutter, in Advances in Virus Research, 2017

  2 History and Development of MVA

  2.1 Ancestry and Generation by Serial Passage

  Modified Vaccinia virus Ankara (MVA) was developed by serial passage in chicken fibroblast tissue culture to serve as safer vaccine during the last years of the WHO smallpox eradication campaign. Its ancestor virus is the vaccinia virus strain Ankara which was originally propagated on the skin of calves and donkeys at the Turkish vaccine institute in Ankara for smallpox vaccine production. In 1953, the vaccinia virus strain Ankara was brought to Munich and added to the strain collection of the Institute for Infectious Diseases and Tropical Medicine at the University of Munich. Herrlich and Mayr cultivated the virus on the chorioallantois membranes (CAM) of embryonatedchicken eggs and therefore named it as Chorioallantois Vaccinia virus Ankara (CVA) (Herrlich and Mayr, 1954). At the Bayerische Landesimpfanstalt München (Bavarian State Institute for Vaccines), CVA was grown on the skin of calves to manufacture smallpox vaccine for the vaccination campaigns in Munich in 1954/1955. In addition, at the University of Munich, CVA was tested in passage experiments in various tissue cultures to study the genetic stability and the evolution of orthopoxviruses. Mayr and Munz (1964)reported that 371 passages of CVA in primary CEF had resulted in the development of an infection phenotype with restricted host (cell) tropism and it was discussed that similar biological properties were known from poxviruses that are highly adapted to specific hosts, e.g., variola virus (VARV) to humans or fowlpox virus to chicken. Successive passage of vaccinia virus in minced chicken embryo tissuehad been described as successful strategy for in vitro amplification of the smallpox vaccine virus in a culture system (Rivers and Ward, 1931, 1933). The serial passage of CVA in CEF was further continued by Anton Mayr and colleagues and, in 1968 after the 516th passage on CEF, the virus was renamed Modifiziertes Vakziniavirus Ankara (MVA) and provided to the Bavarian State Institute for Vaccines to test its suitability for smallpox vaccine production (Stickl and Hochstein-Mintzel, 1971).

  2.2 Early Characterization of Biological Properties

  Phenotypic changes relating to the repeated passage of the CVA virus in CEF cultures were first observed upon infection of the embryonated egg. For many years, CAM inoculations were the gold-standard experimental system for the phenotypic study of various poxviruses (Goodpasture et al., 1931, 1932; Mayr et al., 1955). MVA infection is characterized by the formation of small proliferative lesions on the CAM. In contrast, considerably larger CAM lesions with variable size areas of central necrosis are typically found with CVA or other conventional vaccinia viruses (Herrlich and Mayr, 1954). Interestingly, the CAM lesions of MVA were noted to closely resemble those induced by variola or fowlpox viruses following egg inoculation (Mayr and Munz, 1964; Stickl and Hochstein-Mintzel, 1971). In addition, it was observed early on that MVA had lost the capacity of vaccinia virus to cause prominent cytopathic effects and/or to form plaques in first-generation tissue cultures such as CEF, primary bovine, or porcine kidney cells, or human HeLa cells (Mayr and Munz, 1964). The most characteristic changes in the in vivo behavior of the virus were reported from experimental inoculations of rabbits (German Great White) (Mayr et al., 1975; Stickl and Hochstein-Mintzel, 1971). Intradermal infections or cutaneous infections by scarification with conventional vaccinia virus (VACV) result in the formation of typical skin lesions. Such lesions were totally absent following inoculation with MVA suggesting a substantial loss of virulence upon in vivo infection. These data were confirmed by the finding that newborn (strain NMRI; 1–3 days old) or adult mice (12–15 g) survived intracerebral inoculations of MVA at doses that resulted in 100% mortality following CVA infection (Mayr et al., 1975; Stickl and Hochstein-Mintzel, 1971). The inability of MVA to induce primary reactions with pock lesions forming upon intradermal or cutaneous inoculation was also confirmed in the cynomolgus monkey model (Macacus fascicularis). Macaques tolerated intracranial inoculations with MVA without obvious adverse effects, whereas animals injected with CVA developed severe systemic disease. Moreover, intradermal or intramuscular vaccination with about 2 × 105 infectious units (IU) of MVA vaccine protected macaques from severe disease following intravenous challenge with VARV strain Madras 1965 (Mayr et al., 1975; Stickl and Hochstein-Mintzel, 1971). These data from early preclinical characterization in laboratory animals already suggested that MVA had maintained immunogenicity as vaccine but demonstrated a dramatic loss of virulence. Upon the 516th CEF passage the virus was renamed MVA and transferred to the Bavarian State Vaccine Institute in Munich for evaluation as safer smallpox vaccine in clinical trials.

  2.3 Early Use as Safe Vaccine Against Smallpox

  The first MVA vaccine preparation to be tested in humans was produced in CEF cultures and contained 106 IU MVA/mL (Stickl and Hochstein-Mintzel, 1971). In first attempts, the use of this vaccine by scarification failed to induce any kind of skin reactions and the application by intracutaneous inoculation (0.2 mL vaccine suspension containing 2 × 105 IU MVA) was chosen for first clinical testing and primary vaccination of 107 individuals aged 2–38 years (Stickl and Hochstein-Mintzel, 1971). After 4–6 days, minor local reactions developed at the site of injection with redness and swelling of the skin of the forearm. However, the investigators observed no pock lesions or other symptoms normally associated with smallpox vaccination and none of the 107 individuals developed fever (body temperature ≥ 38 °C). Interestingly, it was noted that the MVA application failed to induce circulation antibodies that inhibited the hemagglutination by VACV. Thus, the efficacy of immunization was tested with secondary vaccination by scarification using VACV strain Elstree in 64 of the 107 individuals that had received MVA for primary vaccination. Skin reactions typical for follow-up smallpox vaccinations were noted in 62 of 64 patients and suggested a successful primary immunization with the MVA vaccine. These data supported further clinical development of MVA as smallpox vaccine and, following the testing in more than 7000 patients (Stickl et al., 1974), the Bavarian State Vaccine Institute in Munich obtained the first marketing authorization for MVA as primary prevaccine against smallpox in Germany in 1977 (Paul-Ehrlich-Institut, 31.01.1977). Until 1980, the MVA smallpox vaccine was given to more than 120,000 humans without documentation of severe adverse events otherwise associated with the use of conventional VACV vaccines (Mahnel and Mayr, 1994). Immunizations with this first licensed MVA vaccine stopped with the end of the smallpox vaccination program in Germany.

  To generate these first MVA vectors, the foreign gene sequences were targeted precisely to the site of the naturally existing deletion III in the MVA genome. This strategy in designing the vector was to avoid unnecessary changes in the genotype and phenotype of the resulting recombinant MVA. The development of other recombinant MVA vaccines with heterologous genes from simian immunodeficiency virus (SIV) or parainfluenza virus 3 inserted in deletion III rapidly followed (Hirsch et al., 1996; Wyatt et al., 1996). Also, the natural deletion II within the MVA genome was successfully used as insertion site to express recombinant bacteriophage T7 RNA polymerase (Sutter et al., 1995). In addition, the thymidine kinase locus, a well-exploited insertion site in replication-competent VACV vectors, likewise, served to generate recombinant MVA delivering antigens of HIV-1 or Plasmodium berghei (Hanke et al., 1998; Schneider et al., 1998).

  
  

  Skin Infections

  Carlos Nicolas Prieto-Granada, ... Martin C. MihmJr., in Diagnostic Pathology of Infectious Disease, 2010

  Vaccinia

  The vaccinia virus (VACV) is antigenically very similar to smallpoxvirus, with both viruses presumably being derived from a common ancestor, a feature that led to the extensive use of VACV as a vaccine against smallpox. Vaccination with VACV confers immunity against several viruses from the Orthopoxvirus genus. Inoculation with VACV leads to cutaneous lesions similar to those seen in smallpox. The inoculation site evolves to a vesicle that becomes pustular, crusts, and finally heals, leaving a scar. Adverse reactions do occur with vaccination, especially in immunocompromised or atopic patients.301,302

  Since 1999, there have been reports of outbreaks involving strains of VACV, particularly in rural areas of Brazil.303-306 In these cases, the clinical picture and transmission mechanisms bear a striking resemblance to cowpox infection (discussed later), including acquisition of the infection from cows through udder lesions and the presence of umbilicated papular lesions with lymphangitis and regional lymphadenopathy.305,306 However, several molecular studies have characterized the causative virus as VACV.303,306 The possible origin, mechanisms of circulation, and reservoirs of these zoonotic VACV infections are largely unknown. It is speculated that VACV could have remained latent in unknown animal reservoirs for decades, because it was relatively common for domestic animals to become infected with VACV from recently vaccinated individuals during the massive smallpox vaccination campaigns of the past.303,307

  Laboratory-acquired infection is also possible, because VACV is extensively used in laboratory-based research in the study of virology, immunology, and vaccine development. Because VACV remains pathogenic to unvaccinated individuals, laboratory workers who handle VACV strains that are not highly attenuated must receive the appropriate vaccine.308

  
  

  Viral and Nonviral Vectors for In Vivo and Ex Vivo Gene Therapies

  A. Crespo-Barreda, ... P. Martin-Duque, in Translating Regenerative Medicine to the Clinic, 2016

  1.1.3 Vaccinia Virus

  1.1.3.1 Generalities

  VV is a poxvirus that was clinically used as vaccine for smallpox. The genome of VV is completely sequenced and facilitates the creation of recombinant viral vectors that could carry up to 25 kb of foreign DNA without the need for viral gene deletions.

  1.1.3.2 Vaccinia Vectors and Genomic Modifications

  VV is a very large, complex, and enveloped virus that contains a linear and dsDNA genome of about 180–190 kbp, with internal terminal repeats, and hairpin loops. The life cycle of the VV occurs in the cytoplasm and so it is a nonintegrative vector.26

  An advantage of using vaccinia-derived vectors is that the vaccinia vectors may carry until 25 kb of foreign DNA without the need for viral deletions.27 Vaccinia vectors present other advantages as a broad host range that permits the infections of primary cultures and many different cell lines, cytoplasmic replication, or the fact that the viral genome does not splice its primary transcripts.

  To regulate the activity levels of the VV-derived vectors, diverse promoters are used, such as natural or synthetic promoters and also early or late expression promoters. Several promoters can be used and are relatively easy to make recombinant viruses, growth, and purify them26 In order to improve the efficiency of the homologous recombination when insertion is desired, other strategies could be used such as the vaccinia–bacteria artificial chromosome technology.28

  Nevertheless, there are problems associated with the host immune response. A vigorous immune response is desirable because it may enhance its potential as vaccine but it might lead to a premature clearance of the virus before adequate levels of replication have occurred. To avoid the early clearance of the virus, vaccinia has developed a wide range of strategies to evade the immune response and to survive in vivo.29

  
  

The Lister Strain of Vaccinia Virus as an Anticancer Therapeutic Agent

Jahangir Ahmed, ... Yaohe Wang, in Gene Therapy of Cancer (Third Edition), 2014

Introduction

Vaccinia virus (VV) has played a prominent role in one of the greatest achievements in medical history—the eradication of smallpox(caused by variola virus). This occurred in the late 1970s, having claimed the lives of half a billion people worldwide in the preceding three centuries [1]. In 1776, Jenner famously inoculated a small boy with pus obtained from a pustule on the hand of a milkmaid [2]. The active therapeutic responsible for the resulting immunity to smallpox was most likely cowpox virus, which is closely related to but taxonomically different from VV [3]. The origin of VV remains obscure, but by the early 20th century it became the foremost smallpox vaccine [3,4].

Although variola is no longer present in any population, threats of bioterrorism from laboratory-preserved derivatives maintain the potential need for rapid widespread vaccination. Vaccine development thus still remains active. In addition, VV has found utility in other roles, including the immunotherapeutic prevention of other infectious diseases [5] as well as in the treatment of cancer [6]. With regard to the latter, the earliest studies (which mainly used replication-attenuated VV recombinants for fear of toxicity) were relatively disappointing in the clinic. Replication-competent VVs retain their ability to lyse tumor cells and spread through tumor tissue. Recent advances in DNA recombinant technology (enabling the rational manipulation of the viral backbone), coupled with the ever-increasing knowledge gains in the fields of molecular virology and cancer cell biology, have aided the development of safe and efficacious replication-competent oncolytic VVs. These are currently at the forefront of the most promising novel anticancer agents.

Different VV strains were used in different areas of the world for mass vaccination. The anticancer potential of the Lister strain (VVL), which was popular in Europe, is the main focus of this chapter.

Poxviruses

G.L. Smith, ... M.A. Skinner, in Encyclopedia of Virology (Third Edition), 2008

Entry

VACV forms two distinct virion types (IMV and EEV), which are surrounded by different numbers of membranes. These different virions are also produced by viruses from several chordopoxvirus genera, and may be universal for poxviruses. IMV enters by fusion of its membrane with either the plasma membrane or the membrane of an intracellular vesicle following endocytosis. EEV entry is complicated by the second membrane that is shed on contact with the cell by a ligand-dependent nonfusogenic process. This places the IMV from within the EEV envelope against the plasma membrane and thereafter entry takes place as for free IMV. A remarkable feature of VACV fusion is the presence of a complex of nine proteins that are all required for fusion but not binding to the cell. In contrast, the fusion machinery of other enveloped viruses is often only a single protein. The fusion proteins of VACV are conserved in many other poxviruses, suggesting a common mechanism of entry. After a virus core has entered the cell, it is transported on microtubules deeper into the cell (see Figure 2(d) for an image of a virus core).

Virus Assembly and Exit Pathways

Nicolas Cifuentes-Munoz, ... Rebecca Ellis Dutch, in Advances in Virus Research, 2020

2.2 Formation of actin tails

Vaccinia virus (VACV) replication occurs in cytosolic factories, and involves the formation of two forms of infectious virus, the intracellular mature virus (IMV) and extracellular enveloped virus (EEV) (Fig. 1). These two forms differ not only antigenically and structurally, but also in the way they exit the cell (Smith and Law, 2004). The majority of IMV particles are released from cells after lysis. Late in infection, IMV particles can also exit the cell through budding, but the significance of this mechanism is not completely understood. Budding from the plasma membrane, together with exocytosis, are the proposed ways that EEV exits cells. However, an important role of the actin cytoskeleton in VACV assembly was identified after early observations using high-voltage electron microscopy (Stokes, 1976). In infected cells, microvilli containing enveloped VACV particles at their tips were observed at the cell periphery (Stokes, 1976). The formation of the microvilli was shown to be sensitive to cytochalasin B but not to nocodazole, suggesting actin polymerization could play a role in their stabilization. The term actin tails was proposed for VACV-induced microvilli, due to their resemblance to actin tails formed in bacterial infections with Listeria, Shigella or Rickettsia (Cudmore et al., 1995; Welch and Way, 2013). Actin tails are initially observed at the interior of the cell, but as the infection progresses they project from the cell surface up to 20 μm. Enveloped virions located at the tip of actin tails were shown to project toward uninfected cells for direct cell-to-cell spread (Fig. 1) (Cudmore et al., 1995). Soon after the discovery of actin tails, it was demonstrated that phosphorylation of the viral protein A36R by Src and Abl family kinases was essential for the actin-based motility of vaccinia (Frischknecht et al., 1999a,b; Newsome et al., 2006). Phosphorylated A36R recruits the adaptor proteins Nck and Grb2 and the downstream effector N-WASP (Wiscott-Aldrich syndrome protein) together with the WASP Interacting Protein (WIP) (Donnelly et al., 2013; Frischknecht et al., 1999b; Scaplehorn et al., 2002). N-WASP can stimulate the actin-nucleating activity of the Arp2/3 complex (Taylor et al., 2011). In addition, activation of the formin FHOD1 by the small GTPase Rac1 was shown to stimulate vaccinia virus-induced actin tail initiation and elongation, a mechanism independent of the N-WASP-Arp2/3 pathway (Alvarez and Agaisse, 2013) (Fig. 1). Two isoforms of cytoplasmic actin, β and γ-actin, are present in actin tails, but only β-actin was found to be involved in actin nucleation induced by VACV (Marzook et al., 2017). Therefore, the signaling pathway initiated through phosphorylation of VACV A36R to induce actin tail formation for direct cell-to-cell spread was found to be an elegant mimic of cellular pathways. More recently, it was shown that two VACV proteins, A33 and A36, are necessary and sufficient to induce actin tail formation. The early expression of both proteins was shown to be crucial for rapid spread and repulsion of virions to neighboring uninfected cells (Doceul et al., 2010). Additional cellular factors such as clathrin and the clathrin adaptor protein AP-2 enhance actin-based motility of vaccinia. Clathrin and AP-2 are recruited by the extracellular virus during its egress to promote clustering of A36, thus potentiating actin-based motility and spread of the infection (Humphries et al., 2012). Casein kinase 2 (CK2) also enhances actin tail formation of vaccinia virus, potentially through direct phosphorylation of A36 and the recruitment of phosphorylated Src (Alvarez and Agaisse, 2012). Though actin tail formation has been explored in detail for vaccinia virus, the sequence homology of key viral proteins and additional evidence suggest that actin tail formation is a common strategy for orthopoxviruses (Duncan et al., 2018; Newsome and Marzook, 2015; Reeves et al., 2011; Welch and Way, 2013).

Sign in to download hi-res image

Fig. 1. Formation of actin tails. Vaccinia virus (VACV) can spread from cell-to-cell through different mechanisms. In VACV infected cells, intracellular enveloped particles are transported to budding sites, where the outer viral membrane fuses with the plasma membrane (A). Extracellular enveloped viral particles remain attached to the plasma membrane and several cellular factors are recruited to the site through a cascade of events initiated by phosphorylation of the A36R protein cytosolic tail (B). Polymerization of F-actin underneath the plasma membrane occurs through activation of the cellular pathways N-WASP/Arp2/3 and FHOD1/Rac1, leading to elongation of actin tails (C). Viral particles can thus reach adjacent cells for rapid direct cell-to-cell spread.

https://www.sciencedirect.com/topics/medicine-and-dentistry/vaccinia-virus

Above. Skillet - Back From the Dead (Official Video)