- Volume 93, Issue 12, 2012
Volume 93, Issue 12, 2012
- Review
-
-
-
Vesicular stomatitis virus as a flexible platform for oncolytic virotherapy against cancer
More LessOncolytic virus (OV) therapy is an emerging anti-cancer approach that utilizes viruses to preferentially infect and kill cancer cells, while not harming healthy cells. Vesicular stomatitis virus (VSV) is a prototypic non-segmented, negative-strand RNA virus with inherent OV qualities. Antiviral responses induced by type I interferon pathways are believed to be impaired in most cancer cells, making them more susceptible to VSV than normal cells. Several other factors make VSV a promising OV candidate for clinical use, including its well-studied biology, a small, easily manipulated genome, relative independence of a receptor or cell cycle, cytoplasmic replication without risk of host-cell transformation, and lack of pre-existing immunity in humans. Moreover, various VSV-based recombinant viruses have been engineered via reverse genetics to improve oncoselectivity, safety, oncotoxicity and stimulation of tumour-specific immunity. Alternative delivery methods are also being studied to minimize premature immune clearance of VSV. OV treatment as a monotherapy is being explored, although many studies have employed VSV in combination with radiotherapy, chemotherapy or other OVs. Preclinical studies with various cancers have demonstrated that VSV is a promising OV; as a result, a human clinical trial using VSV is currently in progress.
-
-
- Animal
-
- RNA viruses
-
-
Typing of viral hemorrhagic septicemia virus by monoclonal antibodies
Seven mAbs with specific reaction patterns against each of the four genotypes and eight subtypes of viral hemorrhagic septicemia virus (VHSV) were produced, aiming to establish an immunoassay for typing VHSV isolates according to their genotype. Among the mAbs, VHS-1.24 reacted with all genotypes except genotype Ie, whilst mAb VHS-9.23 reacted with all genotypes except genotype III. mAb VHS-3.80 reacted with genotypes Ib, Ic, Id and II. mAb VHS-7.57 reacted with genotypes II and IVa, and mAb VHS-5.18 with genotype Ib only. Interestingly, mAb VHS-3.75 reacted with all of the genotype III isolates except a rainbow trout-pathogenic isolate from the west coast of Norway, and reacted in addition with the IVb isolate, CA-NB00-01, from the east coast of the USA. Finally, mAb VHS-1.88 reacted with all genotype IVb isolates from the Great Lakes, but not with CA-NB00-01. In conclusion, we can distinguish between all four genotypes and between five of eight subtypes of VHSV by testing isolates in immunoassay using a panel of nine mAbs. By Western blotting and transfection of cell cultures, it was shown that mAb VHS-1.24 recognized an epitope on the viral phosphoprotein (P), whilst all others recognized antigenic determinants on the nucleoprotein (N). From amino acid alignments of the various genotypes and subtypes of VHSV isolates, it was possible to determine the epitope specificity of mAb VHS-1.24 to be aa 32–34 in the P-protein; the specificities of mAbs VHS-3.80, VHS-7.57 and VHS-3.75 were found to be aa 43 and 45–48, aa 117 and 121, and aa 103, 118 and 121 of the N-protein, respectively.
-
-
-
Inactivation of influenza virus haemagglutinin by chlorine dioxide: oxidation of the conserved tryptophan 153 residue in the receptor-binding site
More LessAirborne influenza virus infection of mice can be prevented by gaseous chlorine dioxide (ClO2). This study demonstrated that ClO2 abolished the function of the haemagglutinin (HA) of influenza A virus (H1N1) in a concentration-, time- and temperature-dependent manner. The IC50 during a 2 min reaction with ClO2 at 25 °C was 13.7 µM, and the half-life time of HA with 100 µM ClO2 at 25 °C was 19.5 s. Peptides generated from a tryptic digest of ClO2-treated virus were analysed by mass spectrometry. An HA fragment, 150NLLWLTGK157 was identified in which the tryptophan residue (W153) was 32 mass units greater than expected. The W153 residue of this peptide, which is derived from the central region of the receptor-binding site of HA, is highly conserved. It was shown that W153 was oxidized to N-formylkynurenine in ClO2-treated virus. It was concluded that the inactivation of influenza virus by ClO2 is caused by oxidation of W153 in HA, thereby abolishing its receptor-binding ability.
-
-
-
Antigenic diversity and cross-reactivity of avian influenza H5N1 viruses in Egypt between 2006 and 2011
Influenza epidemics are a major health concern worldwide. Highly pathogenic avian influenza (HPAI) H5N1 viruses in Egypt have been subject to rapid genetic and antigenic changes since the first outbreak in February 2006 and have been endemic in poultry in Egypt since 2008. In this study, 33 H5N1 viruses isolated from avian hosts were antigenically analysed by using a panel of eight mAbs raised against the A/Viet Nam/1203/04 (H5N1; clade 1) and A/bar-headed goose/Qinghai-lake/1A/05 (H5N1; clade 2.2) influenza viruses. Rats were immunized with inactivated whole-virus vaccine produced by reverse genetics with the haemagglutinin and neuraminidase genes of eight antigenically different HPAI H5N1 virus isolates and six internal genes from A/Puerto Rico/8/1934 (PR8) to produce polyclonal antibodies. Cross-reactivity between the obtained polyclonal antibodies and the isolated viruses was assayed. Antigenic cartography of the isolated viruses showed that three antigenic clusters were defined based on haemagglutination inhibition (HI) analysis using mAbs and the majority of viruses isolated in 2010 and 2011 fell into two of these clusters. An antigenic map based on polyclonal rat antisera showed that all virus isolates fell within one extended cluster. Accordingly, continuous surveillance and antigenic characterization will help us determine which virus isolate(s) should be used in poultry vaccine preparation.
-
-
-
Quantification of heterosubtypic immunity between avian influenza subtypes H3N8 and H4N6 in multiple avian host species
Low-pathogenicity avian influenza virus (LPAIV) can lead to epizootics that cause economic losses in poultry or the emergence of human-infectious strains. LPAIVs experience a complex immunity landscape as they are endemic in numerous host species, and many antigenically distinct strains co-circulate. Prevention and control of emergence of detrimental strains requires an understanding of infection/transmission characteristics of the various subtypes in different hosts, including interactions between subtypes. In order to develop analytical frameworks for examining control efficacy, quantification of heterosubtypic immunity interactions is fundamental. However, these data are scarce, especially for wild avian subtypes in natural hosts. Consequently, in this study, three host species (mallards, quail and pheasants) were infected with two LPAIV subtypes isolated from wild birds: H3N8 and H4N6. The recovered hosts were also reinfected with the alternate subtype to measure the effects of heterosubtypic immunity. Oropharyngeal and cloacal swabs were collected and viral RNA load was quantified by real-time RT-PCR. For secondary infections in recovered hosts, peak viral load was up to four orders of magnitude lower and shedding length was up to 4 days shorter. However, both the magnitude and presence of heterosubtypic immunity varied across specific host species/subtype combinations. Using a mathematical model of virus replication, the variation in virus replication dynamics due to host individuals was quantified. It was found that accounting for individual heterogeneity is important for drawing accurate conclusions about treatment effects. These results are relevant for developing epidemiological models to inform control practices and for analysing virus replication data.
-
-
-
Genomic reassortment of influenza A virus in North American swine, 1998–2011
Revealing the frequency and determinants of reassortment among RNA genome segments is fundamental to understanding basic aspects of the biology and evolution of the influenza virus. To estimate the extent of genomic reassortment in influenza viruses circulating in North American swine, we performed a phylogenetic analysis of 139 whole-genome viral sequences sampled during 1998–2011 and representing seven antigenically distinct viral lineages. The highest amounts of reassortment were detected between the H3 and the internal gene segments (PB2, PB1, PA, NP, M and NS), while the lowest reassortment frequencies were observed among the H1γ, H1pdm and neuraminidase segments, particularly N1. Less reassortment was observed among specific haemagglutinin–neuraminidase combinations that were more prevalent in swine, suggesting that some genome constellations may be evolutionarily more stable.
-
-
-
Evidence of bat origin for Menangle virus, a zoonotic paramyxovirus first isolated from diseased pigs
More LessMenangle virus (MenPV) is a zoonotic paramyxovirus capable of causing disease in pigs and humans. It was first isolated in 1997 from stillborn piglets at a commercial piggery in New South Wales, Australia, where an outbreak of reproductive disease occurred. Neutralizing antibodies to MenPV were detected in various pteropid bat species in Australia and fruit bats were suspected to be the source of the virus responsible for the outbreak in pigs. However, previous attempts to isolate MenPV from various fruit bat species proved fruitless. Here, we report the isolation of MenPV from urine samples of the black flying fox, Pteropus alecto, using a combination of improved procedures and newly established bat cell lines. The nucleotide sequence of the bat isolate is 94 % identical to the pig isolate. This finding provides strong evidence supporting the hypothesis that the MenPV outbreak in pigs originated from viruses in bats roosting near the piggery.
-
-
-
Identification of a novel B-cell epitope of Hantaan virus glycoprotein recognized by neutralizing 3D8 monoclonal antibody
Hantaan virus (HTNV), a member of the family Bunyaviridae, is a major agent causing haemorrhagic fever with renal syndrome, a high-mortality-rate disease threatening approximately 150 000 people around the world yearly. The 3D8 mAb displays a neutralizing activity to HTNV infection. In this study, the B-cell epitopes of HTNV glycoproteins (GPs) were finely mapped by peptide scanning. A new B-cell epitope 882GFLCPEFPGSFRKKC896 of HTNV, which locates on Gc, has been screened out from a set of 15-mer synthesized peptides covering the full-length of HTNV-GPs. It has been shown by the alanine-scanning technique that 885C, 893R, 894K, 895K and 896C are the key amino acids of the binding sites of the GPs. The implications of identifying a novel B-cell epitope for hantavirus immunology and vaccinology are discussed.
-
-
-
Combined action of type I and type III interferon restricts initial replication of severe acute respiratory syndrome coronavirus in the lung but fails to inhibit systemic virus spread
STAT1-deficient mice are more susceptible to infection with severe acute respiratory syndrome coronavirus (SARS-CoV) than type I interferon (IFN) receptor-deficient mice. We used mice lacking functional receptors for both type I and type III IFN (double knockout, dKO) to evaluate the possibility that type III IFN plays a decisive role in SARS-CoV protection. We found that viral peak titres in lungs of dKO and STAT1-deficient mice were similar, but significantly higher than in wild-type mice. The kinetics of viral clearance from the lung were also comparable in dKO and STAT1-deficient mice. Surprisingly, however, infected dKO mice remained healthy, whereas infected STAT1-deficient mice developed liver pathology and eventually succumbed to neurological disease. Our data suggest that the failure of STAT1-deficient mice to control initial SARS-CoV replication efficiently in the lung is due to impaired type I and type III IFN signalling, whereas the failure to control subsequent systemic viral spread is due to unrelated defects in STAT1-deficient mice.
-
-
-
Characterization of a full-length infectious cDNA clone and a GFP reporter derivative of the oncolytic picornavirus SVV-001
Seneca Valley virus (SVV-001) is an oncolytic picornavirus with selective tropism for a subset of human cancers with neuroendocrine differentiation. To characterize further the specificity of SVV-001 and its patterns and kinetics of intratumoral spread, bacterial plasmids encoding a cDNA clone of the full-length wild-type virus and a derivative virus expressing GFP were generated. The full-length cDNA of the SVV-001 RNA genome was cloned into a bacterial plasmid under the control of the T7 core promoter sequence to create an infectious cDNA clone, pNTX-09. A GFP reporter virus cDNA clone, pNTX-11, was then generated by cloning a fusion protein of GFP and the 2A protein from foot-and-mouth disease virus immediately following the native SVV-001 2A sequence. Recombinant GFP-expressing reporter virus, SVV–GFP, was rescued from cells transfected with in vitro RNA transcripts from pNTX-11 and propagated in cell culture. The proliferation kinetics of SVV-001 and SVV–GFP were indistinguishable. The SVV–GFP reporter virus was used to determine that a subpopulation of permissive cells is present in small-cell lung cancer cell lines previously thought to lack permissivity to SVV-001. Finally, it was shown that SVV–GFP administered to tumour-bearing animals homes in to and infects tumours whilst having no detectable tropism for normal mouse tissues at 1×1011 viral particles kg−1, a dose equivalent to that administered in ongoing clinical trials. These infectious clones will be of substantial value in further characterizing the biology of this virus and as a backbone for the generation of additional oncolytic derivatives.
-
-
-
Insertion and recombination events at hypervariable region 1 over 9.6 years of hepatitis C virus chronic infection
Hepatitis C virus (HCV) exists as a quasispecies within an infected individual. We have previously reported an in-frame 3 bp insertion event at the N-terminal region of the E2 glycoprotein from a genotype 4a HCV isolate giving rise to an atypical 28 aa hypervariable region (HVR) 1. To further explore quasispecies evolution at the HVR1, serum samples collected over 9.6 years from the same chronically infected, treatment naïve individual were subjected to retrospective clonal analysis. Uniquely, we observed that isolates containing this atypical HVR1 not only persisted for 7.6 years, but dominated the quasispecies swarm. Just as striking was the collapse of this population of variants towards the end of the sampling period in synchrony with variants containing a classical HVR1 from the same lineage. The replication space was subsequently occupied by a second minor lineage, which itself was only intermittently detectable at earlier sampling points. In conjunction with the observed genetic shift, the coexistence of two distinct HVR1 populations facilitated the detection of putative intra-subtype recombinants, which included the identification of the likely ancestral parental donors. Juxtaposed to the considerable plasticity of the HVR1, we also document a degree of mutational inflexibility as each of the HVR1 subpopulations within our dataset exhibited overall genetic conservation and convergence. Finally, we raise the issue of genetic analysis in the context of mixed lineage infections.
-
-
-
Evolution of the human immunodeficiency virus type 1 protease: effects on viral replication capacity and protease robustness
More LessThe rapid spread of human immunodeficiency virus type 1 (HIV-1) in humans has been accompanied by continuous extensive genetic diversification of the virus. The aim of this study was to investigate the impact of HIV-1 diversification on HIV-1 replication capacity (RC) and mutational robustness. Thirty-three HIV-1 protease sequences were amplified from three groups of viruses: two naïve sample groups isolated 15 years apart plus a third group of protease inhibitor-(PI) resistant samples. The amplified proteases were recombined with an HXB2 infectious clone and RC was determined in MT-4 cells. RC was also measured in these three groups after random mutagenesis in vitro using error-prone PCR. No significant RC differences were observed between recombinant viruses from either early or recent naïve isolates (P = 0.5729), even though the proteases from the recent isolates had significantly lower sequence conservation scores compared with a subtype B ancestral sequence (P<0.0001). Randomly mutated recombinant viruses from the three groups exhibited significantly lower RC values than the corresponding wild-type viruses (P<0.0001). There was no significant difference regarding viral infectivity reduction between viruses carrying randomly mutated naïve proteases from early or recent sample isolates (P = 0.8035). Interestingly, a significantly greater loss of RC was observed in the PI-resistant protease group (P = 0.0400). These results demonstrate that protease sequence diversification has not affected HIV-1 RC or protease robustness and indicate that proteases carrying PI resistance substitutions are less robust than naïve proteases.
-
-
-
Comparative analysis of the fusion efficiency elicited by the envelope glycoprotein V1–V5 regions derived from human immunodeficiency virus type 1 transmitted perinatally
Understanding the properties of viruses preferentially establishing infection during perinatal transmission of human immunodeficiency virus type 1 (HIV-1) is critical for the development of effective measures to prevent transmission. A previous study demonstrated that the newly transmitted viruses (in infants) of chronically infected mother–infant pairs (MIPs) were fitter in terms of growth, which was imparted by their envelope (Env) glycoprotein V1–V5 regions, than those in the corresponding chronically infected mothers. In order to investigate whether the higher fitness of transmitted viruses was conferred by their higher entry efficiency directed by the V1–V5 regions during perinatal transmission, the fusogenicity of Env containing V1–V5 regions derived from transmitted and non-tranmsmitted viruses of five chronically infected MIPs and two acutely infected MIPs was analysed using two different cell–cell fusion assays. The results showed that, in one chronically infected MIP, a higher fusion efficiency was induced by the infant Env V1–V5 compared with that of the corresponding mother. Moreover, the V4–V5 regions played an important role in discriminating the transmitted and non-transmitted viruses in this pair. However, neither a consistent pattern nor significant differences in fusogenicity mediated by the V1–V5 regions between maternal and infant variants was observed in the other MIPs. This study suggests that there is no consistent and significant correlation between viral fitness selection and entry efficiency directed by the V1–V5 regions during perinatal transmission. Other factors such as the route and timing of transmission may also be involved.
-
-
-
Hyperediting of human T-cell leukemia virus type 2 and simian T-cell leukemia virus type 3 by the dsRNA adenosine deaminase ADAR-1
More LessRNA editing mediated by adenosine deaminases acting on RNA (ADARs) converts adenosine (A) to inosine (I) residues in dsRNA templates. While ADAR-1-mediated editing was essentially described for RNA viruses, the present work addresses the issue for two δ-retroviruses, human T-cell leukemia virus type 2 and simian T-cell leukemia virus type 3 (HTLV-2 and STLV-3). We examined whether ADAR-1 could edit HTLV-2 and STLV-3 virus genomes in cell culture and in vivo. Using a highly sensitive PCR-based method, referred to as 3DI-PCR, we showed that ADAR-1 could hypermutate adenosine residues in HTLV-2. STLV-3 hypermutation was obtained without using 3DI-PCR, suggesting a higher mutation frequency for this virus. Detailed analysis of the dinucleotide editing context showed preferences for 5′ ArA and 5′ UrA. In conclusion, the present observations demonstrate that ADAR-1 massively edits HTLV-2 and STLV-3 retroviruses in vitro, but probably remains a rare phenomenon in vivo.
-
- DNA viruses
-
-
Novel polyomaviruses in South American bats and their relationship to other members of the family Polyomaviridae
Bats are the natural reservoir of a variety of viruses, including a polyomavirus (PyV) from a North American brown bat. We investigated 163 spleen samples from 22 bat species from French Guiana for the presence of PyVs. In total, we detected 25 PyV-positive animals belonging to nine different bat species. Phylogenetic analysis was performed on the genomes of eight representative PyVs, and showed that the bat PyVs form three distinct lineages within the genus Orthopolyomavirus and are genetically different from the previously described North American bat virus. Interestingly, two lineages cluster with PyVs found in chimpanzees, orangutans and gorillas. In addition, one group of bat PyVs is genetically related to the human Merkel cell polyomavirus.
-
-
-
Serological cross-reactions between four polyomaviruses of birds using virus-like particles expressed in yeast
More LessPolyomaviruses are aetiological agents of fatal acute diseases in various bird species. Genomic analysis revealed that avian polyomavirus (APyV), crow polyomavirus (CPyV), finch polyomavirus (FPyV) and goose hemorrhagic polyomavirus (GHPyV) are closely related to each other, but nevertheless form separate viral species; however, their serological relationship was previously unknown. As only APyV can be grown efficiently in tissue culture, virus-like particles (VLPs) were generated by expression of the genomic regions encoding the major structural protein VP1 of these viruses in yeast; these were used to elicit type-specific antibodies in rabbits and as antigens in serological reactions. For increased VLP assembly, a nuclear-localization signal was introduced into APyV-VP1. VLPs derived from the VP1 of the monkey polyomavirus simian virus 40 served as control. APyV-, GHPyV- and CPyV-VLPs showed haemagglutinating activity with chicken and human erythrocytes. CPyV- and GHPyV-specific sera showed slight cross-reactions in immunoblotting, haemagglutination-inhibition assay and indirect ELISA. The FPyV-specific serum inhibited the haemagglutination activity of APyV-VLPs slightly and showed a weak cross-neutralizing activity against APyV in cell-culture tests. Generally, these data indicate that the four polyomaviruses of birds are serologically distinct. However, in accordance with genetic data, a relationship between CPyV and GHPyV as well as between APyV and FPyV is evident, and grouping into two different serogroups may be suggested. The haemagglutinating activity of APyV, CPyV and GHPyV may indicate similar receptor-binding mechanisms for these viruses. Our data could be useful for the development of vaccines against the polyomavirus-induced diseases in birds and for interpretation of diagnostic test results.
-
-
-
Diverse circular ssDNA viruses discovered in dragonflies (Odonata: Epiprocta)
Viruses with circular ssDNA genomes that encode a replication initiator protein (Rep) are among the smallest viruses known to infect both eukaryotic and prokaryotic organisms. In the past few years an overwhelming diversity of novel circular Rep-encoding ssDNA (CRESS-DNA) viruses has been unearthed from various hosts and environmental sources. Since there is limited information regarding CRESS-DNA viruses in invertebrates, this study explored the diversity of CRESS-DNA viruses circulating among insect populations by targeting dragonflies (Epiprocta), top insect predators that accumulate viruses from their insect prey over space and time. Using degenerate PCR and rolling circle amplification coupled with restriction digestion, 17 CRESS-DNA viral genomes were recovered from eight different dragonfly species collected in tropical and temperate regions. Nine of the genomes are similar to cycloviruses and represent five species within this genus, suggesting that cycloviruses are commonly associated with insects. Three of the CRESS-DNA viruses share conserved genomic features with recently described viruses similar to the mycovirus Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1, leading to the proposal of the genus Gemycircularvirus. The remaining viruses are divergent species representing four novel CRESS-DNA viral genera, including a gokushovirus-like prokaryotic virus (microphage) and three eukaryotic viruses with Reps similar to circoviruses. The novelty of CRESS-DNA viruses identified in dragonflies using simple molecular techniques indicates that there is an unprecedented diversity of ssDNA viruses among insect populations.
-
-
-
Discovery of a novel Torque teno sus virus species: genetic characterization, epidemiological assessment and disease association
The study describes a novel Torque teno sus virus (TTSuV) species, provisionally named Torque teno sus virus k2b (TTSuVk2b), originally found in commercial pig sera by applying the rolling-circle amplification technique. Full-length sequences of TTSuVk2b were obtained, annotated and used in the phylogenetic analyses, which revealed that TTSuVk2b is a novel Anellovirus species within the genus Kappatorquevirus of the family Anelloviridae. Quantitative PCR techniques were developed to determine total TTSuV DNA quantities as well as the prevalence and viral DNA quantities of TTSuV1, TTSuVk2a and TTSuVk2b. The mean total TTSuV load in seven commercial sera was determined at 6.3 log10 DNA copies ml−1 of serum, with TTSuVk2b loads being the lowest at 4.5 log10 DNA copies ml−1 of serum. Subsequently, prevalence and loads of TTSuVs were determined in pig sera from 17 countries. TTSuVk2b prevalence ranged from 0 to 100 % with viral loads from 3.3 to 4.6 log10 copies ml−1 of sera. TTSuVk2a, so far the only species in the genus Kappatorquevirus, has been linked to an economically important swine disease, namely post-weaning multisystemic wasting syndrome (PMWS). Considering the grouping of TTSuVk2b in the same genus as TTSuVk2a, TTSuVk2b prevalence and viral DNA load were determined in PMWS-affected animals and healthy counterparts. This revealed that TTSuVk2a and TTSuVk2b are not only genetically related, but also that their viral loads in serum are elevated in PMWS animals compared with those of healthy pen mates. In summary, the present work describes a novel TTSuV species including its genetic characterization, epidemiological assessment and potential disease association.
-
-
-
Interclade recombination in porcine parvovirus strains
More LessA detailed analysis of the Ns1/Vp1Vp2 genome region of the porcine parvovirus (PPV) strains isolated from vaccinated animals was performed. We found many inconsistencies in the phylogenetic trees of these viral isolates, such as low statistical support and strains with long branches in the phylogenetic trees. Thus, we used distance-based and phylogenetic methods to distinguish de facto recombinants from spurious recombination signals. We found a mosaic virus in which the Ns1 gene was acquired from one PPV clade and the Vp1Vp2 gene was acquired from a distinct phylogenetic clade. We also described the interclade mosaic structure of the Vp1Vp2 gene of a reference strain. If recombination is an adaptive mechanism over the course of PPV evolution, we would likely observe increasing numbers of chimeric strains over time. However, when the PPV sequences isolated from 1964 to 2011 were analysed, only two chimeric strains were detected. Thus, PPV recombination is an independent event, resulting from close contact between animals housed in high-density conditions.
-
-
-
Incorporation of GP64 into Helicoverpa armigera nucleopolyhedrovirus enhances virus infectivity in vivo and in vitro
More LessThe envelope fusion proteins of baculoviruses, glycoprotein GP64 from group I nucleopolyhedrovirus (NPV) or the F protein from group II NPV and granulovirus, are essential for baculovirus morphogenesis and infectivity. The F protein is considered the ancestral baculovirus envelope fusion protein, while GP64 is a more recent evolutionary introduction into baculoviruses and exhibits higher fusogenic activity than the F protein. Each of the fusion proteins is required by the respective virus to spread infection within larval tissues. A recombinant Helicoverpa armigera NPV (HearNPV) expressing GP64 from Autographa californica multiple nucleopolyhedrovirus, vHaBac-gp64-egfp, was constructed, which still retained the native F protein, and its infectivity was assayed in vivo and in vitro. Analyses by one-step growth curve to determine viral titre and by quantitative PCR to determine viral DNA copy number showed that vHaBac-gp64-egfp was more infectious in vitro than the control, vHaBac-egfp. The polyhedrin gene (polh) was reintroduced into the recombinant viruses and bioassays showed that vHaBac-gp64-polh accelerated the mortality of infected larvae compared with the vHaBac-egfp-polh control, and the LC50 (median lethal concentration) of vHaBac-gp64-polh was reduced to approximately 20 % of that of vHaBac-egfp-polh. Therefore, incorporation of GP64 into HearNPV budded virions improved virus infectivity both in vivo and in vitro. The construction of this bivalent virus with a more efficient fusion protein could improve the use of baculoviruses in different areas such as gene therapy and biocontrol.
-
Volumes and issues
-
Volume 105 (2024)
-
Volume 104 (2023)
-
Volume 103 (2022)
-
Volume 102 (2021)
-
Volume 101 (2020)
-
Volume 100 (2019)
-
Volume 99 (2018)
-
Volume 98 (2017)
-
Volume 97 (2016)
-
Volume 96 (2015)
-
Volume 95 (2014)
-
Volume 94 (2013)
-
Volume 93 (2012)
-
Volume 92 (2011)
-
Volume 91 (2010)
-
Volume 90 (2009)
-
Volume 89 (2008)
-
Volume 88 (2007)
-
Volume 87 (2006)
-
Volume 86 (2005)
-
Volume 85 (2004)
-
Volume 84 (2003)
-
Volume 83 (2002)
-
Volume 82 (2001)
-
Volume 81 (2000)
-
Volume 80 (1999)
-
Volume 79 (1998)
-
Volume 78 (1997)
-
Volume 77 (1996)
-
Volume 76 (1995)
-
Volume 75 (1994)
-
Volume 74 (1993)
-
Volume 73 (1992)
-
Volume 72 (1991)
-
Volume 71 (1990)
-
Volume 70 (1989)
-
Volume 69 (1988)
-
Volume 68 (1987)
-
Volume 67 (1986)
-
Volume 66 (1985)
-
Volume 65 (1984)
-
Volume 64 (1983)
-
Volume 63 (1982)
-
Volume 62 (1982)
-
Volume 61 (1982)
-
Volume 60 (1982)
-
Volume 59 (1982)
-
Volume 58 (1982)
-
Volume 57 (1981)
-
Volume 56 (1981)
-
Volume 55 (1981)
-
Volume 54 (1981)
-
Volume 53 (1981)
-
Volume 52 (1981)
-
Volume 51 (1980)
-
Volume 50 (1980)
-
Volume 49 (1980)
-
Volume 48 (1980)
-
Volume 47 (1980)
-
Volume 46 (1980)
-
Volume 45 (1979)
-
Volume 44 (1979)
-
Volume 43 (1979)
-
Volume 42 (1979)
-
Volume 41 (1978)
-
Volume 40 (1978)
-
Volume 39 (1978)
-
Volume 38 (1978)
-
Volume 37 (1977)
-
Volume 36 (1977)
-
Volume 35 (1977)
-
Volume 34 (1977)
-
Volume 33 (1976)
-
Volume 32 (1976)
-
Volume 31 (1976)
-
Volume 30 (1976)
-
Volume 29 (1975)
-
Volume 28 (1975)
-
Volume 27 (1975)
-
Volume 26 (1975)
-
Volume 25 (1974)
-
Volume 24 (1974)
-
Volume 23 (1974)
-
Volume 22 (1974)
-
Volume 21 (1973)
-
Volume 20 (1973)
-
Volume 19 (1973)
-
Volume 18 (1973)
-
Volume 17 (1972)
-
Volume 16 (1972)
-
Volume 15 (1972)
-
Volume 14 (1972)
-
Volume 13 (1971)
-
Volume 12 (1971)
-
Volume 11 (1971)
-
Volume 10 (1971)
-
Volume 9 (1970)
-
Volume 8 (1970)
-
Volume 7 (1970)
-
Volume 6 (1970)
-
Volume 5 (1969)
-
Volume 4 (1969)
-
Volume 3 (1968)
-
Volume 2 (1968)
-
Volume 1 (1967)