Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Mol Ther ; 30(9): 2984-2997, 2022 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-35484842

RESUMO

As the coronavirus disease 2019 (COVID-19) pandemic continues and new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern emerge, the adaptive immunity initially induced by the first-generation COVID-19 vaccines starts waning and needs to be strengthened and broadened in specificity. Vaccination by the nasal route induces mucosal, humoral, and cellular immunity at the entry point of SARS-CoV-2 into the host organism and has been shown to be the most effective for reducing viral transmission. The lentiviral vaccination vector (LV) is particularly suitable for this route of immunization owing to its non-cytopathic, non-replicative, and scarcely inflammatory properties. Here, to set up an optimized cross-protective intranasal booster against COVID-19, we generated an LV encoding stabilized spike of SARS-CoV-2 Beta variant (LV::SBeta-2P). mRNA vaccine-primed and -boosted mice, with waning primary humoral immunity at 4 months after vaccination, were boosted intranasally with LV::SBeta-2P. A strong boost effect was detected on cross-sero-neutralizing activity and systemic T cell immunity. In addition, mucosal anti-spike IgG and IgA, lung-resident B cells, and effector memory and resident T cells were efficiently induced, correlating with complete pulmonary protection against the SARS-CoV-2 Delta variant, demonstrating the suitability of the LV::SBeta-2P vaccine candidate as an intranasal booster against COVID-19. LV::SBeta-2P vaccination was also fully protective against Omicron infection of the lungs and central nervous system, in the highly susceptible B6.K18-hACE2IP-THV transgenic mice.


Assuntos
COVID-19 , Vacinas Virais , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Vacinas contra COVID-19 , Humanos , Pulmão , Camundongos , Mucosa , SARS-CoV-2/genética , Vacinação , Vacinas Sintéticas , Vacinas de mRNA
2.
Pharmaceutics ; 15(3)2023 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-36986707

RESUMO

Lentiviral vectors are among the most effective viral vectors for vaccination. In clear contrast to the reference adenoviral vectors, lentiviral vectors have a high potential for transducing dendritic cells in vivo. Within these cells, which are the most efficient at activating naive T cells, lentiviral vectors induce endogenous expression of transgenic antigens that directly access antigen presentation pathways without the need for external antigen capture or cross-presentation. Lentiviral vectors induce strong, robust, and long-lasting humoral, CD8+ T-cell immunity and effective protection against several infectious diseases. There is no pre-existing immunity to lentiviral vectors in the human population and the very low pro-inflammatory properties of these vectors pave the way for their use in mucosal vaccination. In this review, we have mainly summarized the immunological aspects of lentiviral vectors, their recent optimization to induce CD4+ T cells, and our recent data on lentiviral vector-based vaccination in preclinical models, including prophylaxis against flaviviruses, SARS-CoV-2, and Mycobacterium tuberculosis.

3.
Front Immunol ; 14: 1208041, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37654495

RESUMO

Dengue virus (DENV) is responsible for approximately 100 million cases of dengue fever annually, including severe forms such as hemorrhagic dengue and dengue shock syndrome. Despite intensive vaccine research and development spanning several decades, a universally accepted and approved vaccine against dengue fever has not yet been developed. The major challenge associated with the development of such a vaccine is that it should induce simultaneous and equal protection against the four DENV serotypes, because past infection with one serotype may greatly increase the severity of secondary infection with a distinct serotype, a phenomenon known as antibody-dependent enhancement (ADE). Using a lentiviral vector platform that is particularly suitable for the induction of cellular immune responses, we designed a tetravalent T-cell vaccine candidate against DENV ("LV-DEN"). This vaccine candidate has a strong CD8+ T-cell immunogenicity against the targeted non-structural DENV proteins, without inducing antibody response against surface antigens. Evaluation of its protective potential in the preclinical flavivirus infection model, i.e., mice knockout for the receptor to the type I IFN, demonstrated its significant protective effect against four distinct DENV serotypes, based on reduced weight loss, viremia, and viral loads in peripheral organs of the challenged mice. These results provide proof of concept for the use of lentiviral vectors for the development of efficient polyvalent T-cell vaccine candidates against all DENV serotypes.


Assuntos
Vírus da Dengue , Dengue Grave , Animais , Camundongos , Vacinas Combinadas , Linfócitos T CD8-Positivos , Anticorpos Facilitadores
4.
Microbes Infect ; 25(7): 105142, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37080384

RESUMO

Human Angiotensin-Converting Enzyme 2 (hACE2) is the major receptor enabling host cell invasion by SARS-CoV-2 via interaction with Spike. The murine ACE2 does not interact efficiently with SARS-CoV-2 Spike and therefore the laboratory mouse strains are not permissive to SARS-CoV-2 replication. Here, we generated new hACE2 transgenic mice, which harbor the hACE2 gene under the human keratin 18 promoter, in "HHD-DR1" background. HHD-DR1 mice are fully devoid of murine Major Histocompatibility Complex (MHC) molecules of class-I and -II and express only MHC molecules from Human Leukocyte Antigen (HLA) HLA 02.01, DRA01.01, DRB1.01.01 alleles, widely expressed in human populations. We selected three transgenic strains, with various hACE2 mRNA expression levels and distinctive profiles of lung and/or brain permissiveness to SARS-CoV-2 replication. These new hACE2 transgenic strains display high permissiveness to the replication of SARS-CoV-2 Omicron sub-variants, while the previously available B6.K18-ACE22Prlmn/JAX mice have been reported to be poorly susceptible to infection with Omicron. As a first application, one of these MHC- and ACE2-humanized strains was successfully used to show the efficacy of a lentiviral-based COVID-19 vaccine.


Assuntos
Enzima de Conversão de Angiotensina 2 , COVID-19 , Animais , Camundongos , Humanos , Enzima de Conversão de Angiotensina 2/genética , SARS-CoV-2/genética , Vacinas contra COVID-19 , Permissividade , Complexo Principal de Histocompatibilidade , Camundongos Transgênicos
5.
J Virol ; 85(4): 1747-56, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21106742

RESUMO

Hantaviruses, the causative agents of two emerging diseases, are negative-stranded RNA viruses with a tripartite genome. We isolated two substrains from a parental strain of Puumala hantavirus (PUUV-Pa), PUUV-small (PUUV-Sm) and PUUV-large (PUUV-La), named after their focus size when titrated. The two isolates were sequenced; this revealed differences at two positions in the nucleocapsid protein and two positions in the RNA-dependent RNA polymerase, but the glycoproteins were identical. We also detected a 43-nucleotide deletion in the PUUV-La S-segment 5' noncoding region covering a predicted hairpin loop structure that was found to be conserved among all hantaviruses with members of the rodent subfamily Arvicolinae as their hosts. Stocks of PUUV-La showed a lower ratio of viral RNA to infectious particles than stocks of PUUV-Sm and PUUV-Pa, indicating that PUUV-La replicated more efficiently in alpha/beta interferon (IFN-α/ß)-defective Vero E6 cells. In Vero E6 cells, PUUV-La replicated to higher titers and PUUV-Sm replicated to lower titers than PUUV-Pa. In contrast, in IFN-competent MRC-5 cells, PUUV-La and PUUV-Sm replicated to similar levels, while PUUV-Pa progeny virus production was strongly inhibited. The different isolates clearly differed in their potential to induce innate immune responses in MRC-5 cells. PUUV-Pa caused stronger induction of IFN-ß, ISG56, and MxA than PUUV-La and PUUV-Sm, while PUUV-Sm caused stronger MxA and ISG56 induction than PUUV-La. These data demonstrate that the phenotypes of isolated hantavirus substrains can have substantial differences compared to each other and to the parental strain. Importantly, this implies that the reported differences in phenotypes for hantaviruses might depend more on chance due to spontaneous mutations during passage than inherited true differences between hantaviruses.


Assuntos
Células Epiteliais/virologia , Fibroblastos/virologia , Rim/virologia , Pulmão/virologia , Virus Puumala/classificação , Virus Puumala/fisiologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Chlorocebus aethiops , Humanos , Rim/citologia , Pulmão/citologia , Dados de Sequência Molecular , Mutação , Proteínas do Nucleocapsídeo/química , Proteínas do Nucleocapsídeo/genética , Fenótipo , Virus Puumala/genética , Virus Puumala/imunologia , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/genética , Análise de Sequência de DNA , Especificidade da Espécie , Células Vero , Proteínas Virais/química , Proteínas Virais/genética , Replicação Viral
6.
J Infect Dis ; 204 Suppl 3: S884-91, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21987765

RESUMO

The matrix protein VP40 is essential for Ebola virus (EBOV) and Marburg virus assembly and budding at the plasma membrane. In this study we have investigated the effect of single amino acid substitutions in a conserved proline-rich region of the EBOV VP40 located in the carboxy-terminal part of the protein. We demonstrate that substitutions within this region result in an alteration of intracellular VP40 localization and also cause a reduction or a complete block of virus-like particle budding, a benchmark of VP40 function. Furthermore, some mutated VP40s revealed an enhanced binding with cellular Sec24C, a part of the coat protein complex II (COPII) vesicular transport system. Analysis of the 3-dimensional structure of VP40 revealed the spatial proximity of the proline-rich region and an earlier identified site of interaction with Sec24C, thus allowing us to hypothesize that the altered intracellular localization of the VP40 mutants is a consequence of defects in their interaction with COPII-mediated vesicular transport.


Assuntos
Membrana Celular/metabolismo , Ebolavirus/metabolismo , Prolina/química , Proteínas da Matriz Viral/metabolismo , Liberação de Vírus/fisiologia , Animais , Chlorocebus aethiops , Células HEK293 , Humanos , Modelos Moleculares , Nocodazol/farmacologia , Conformação Proteica , Transporte Proteico , Moduladores de Tubulina/farmacologia , Células Vero , Proteínas da Matriz Viral/química , Proteínas da Matriz Viral/genética
7.
J Infect Dis ; 204 Suppl 3: S1011-20, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21987737

RESUMO

In sharp contrast to human and nonhuman primates, guinea pigs and some other mammals resist Ebola virus (EBOV) replication and do not develop illness upon virus inoculation. However, serial passaging of EBOV in guinea pigs results in a selection of variants with high pathogenicity. In this report, using a reverse genetics approach, we demonstrate that this dramatic increase in EBOV pathogenicity is associated with amino acid substitutions in the structural protein VP24. We show that although replication of recombinant EBOV carrying wild-type VP24 is impaired in primary peritoneal guinea pig macrophages and in the liver of infected animals, the substitutions in VP24 allow EBOV to replicate in guinea pig macrophages and spread in the liver of infected animals. Furthermore, we demonstrate that both VP24/wild type and the guinea pig-adapted VP24/8mc are similar in their ability to block expression of interferon-induced host genes, suggesting that the increase in EBOV virulence for guinea pigs is not associated with VP24 interferon antagonist function. This study sheds light on the mechanism of resistance to EBOV infection and highlights the critical role of VP24 in EBOV pathogenesis.


Assuntos
Ebolavirus/metabolismo , Ebolavirus/patogenicidade , Doença pelo Vírus Ebola/virologia , Proteínas Virais/metabolismo , Animais , Linhagem Celular , Ebolavirus/classificação , Ebolavirus/genética , Feminino , Regulação Viral da Expressão Gênica/fisiologia , Cobaias , Humanos , Fígado/ultraestrutura , Macrófagos/virologia , Mutação , Virulência , Replicação Viral
8.
Vaccines (Basel) ; 11(1)2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36679857

RESUMO

Following the breakthrough of numerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants in recent months and the incomplete efficiency of the currently available vaccines, development of more effective vaccines is desirable. Non-integrative, non-cytopathic and non-inflammatory lentiviral vectors elicit sterilizing prophylaxis against SARS-CoV-2 in preclinical animal models and are particularly suitable for mucosal vaccination, which is acknowledged as the most effective in reducing viral transmission. Here, we demonstrate that a single intranasal administration of a vaccinal lentiviral vector encoding a stabilized form of the original SARS-CoV-2 Spike glycoprotein induces full-lung protection of respiratory tracts and strongly reduces pulmonary inflammation in the susceptible Syrian golden hamster model against the prototype SARS-CoV-2. In addition, we show that a lentiviral vector encoding stabilized Spike of SARS-CoV-2 Beta variant (LV::SBeta-2P) prevents pathology and reduces infectious viral loads in lungs and nasal turbinates following inoculation with the SARS-CoV-2 Omicron variant. Importantly, an intranasal boost with LV::SBeta-2P improves cross-seroneutralization much better in LV::SBeta-2P-primed hamsters than in their counterparts primed with an LV-encoding Spike from the ancestral SARS-CoV-2. These results strongly suggest that an immune imprint with the original Spike sequence has a negative impact on cross-protection against new variants. Our results tackle the issue of vaccine effectiveness in people who have already been vaccinated and have vanished immunity and indicate the efficiency of LV-based intranasal vaccination, either as a single dose or as booster.

9.
J Med Virol ; 83(1): 108-14, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21108346

RESUMO

In Europe, Dobrava-Belgrade (DOBV), Saaremaa (SAAV), and Puumala (PUUV) viruses are known to cause hemorrhagic fever with renal syndrome (HFRS). All three hantaviruses are now found in Croatia. Lung tissue samples of 315 Apodemus mice trapped in 2003-2004 were screened for the presence of hantaviral N-Ag and 20 mice (6.3%) were found either strongly positive or weak/suspected-positive. Partial sequences of hantavirus M and S segments were recovered by RT-PCR from six mice and subjected to (phylo)genetic analysis that revealed the presence of four novel strains of DOBV and one of SAAV. Curiously, one of the newly described DOBV strains was found in Apodemus agrarius mouse, that is, not in the traditional host, A. flavicollis mice, suggesting a spillover event. S segment sequences recovered previously from HFRS cases [Markotic et al., 2002] were confirmed as DOBV sequences; one of which appeared particularly close to the prototype Slovenian DOBV isolate. Taken together with earlier data on PUUV in Croatia, these results show a co-circulation of three European hantavirus pathogens in this country. So far, not a single SAAV sequence has been recovered from HFRS patients either in Croatia or neighboring Slovenia and Hungary nor in Slovakia suggesting a somewhat lower fequency of acute SAAV infection in humans in this part of Europe than for example in the Baltics.


Assuntos
Murinae/virologia , Orthohantavírus/classificação , Orthohantavírus/isolamento & purificação , Animais , Análise por Conglomerados , Croácia , Orthohantavírus/genética , Pulmão/virologia , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência
10.
EMBO Mol Med ; 13(12): e14459, 2021 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-34647691

RESUMO

COVID-19 vaccines already in use or in clinical development may have reduced efficacy against emerging SARS-CoV-2 variants. In addition, although the neurotropism of SARS-CoV-2 is well established, the vaccine strategies currently developed have not taken into account protection of the central nervous system. Here, we generated a transgenic mouse strain expressing the human angiotensin-converting enzyme 2, and displaying unprecedented brain permissiveness to SARS-CoV-2 replication, in addition to high permissiveness levels in the lung. Using this stringent transgenic model, we demonstrated that a non-integrative lentiviral vector, encoding for the spike glycoprotein of the ancestral SARS-CoV-2, used in intramuscular prime and intranasal boost elicits sterilizing protection of lung and brain against both the ancestral virus, and the Gamma (P.1) variant of concern, which carries multiple vaccine escape mutations. Beyond induction of strong neutralizing antibodies, the mechanism underlying this broad protection spectrum involves a robust protective T-cell immunity, unaffected by the recent mutations accumulated in the emerging SARS-CoV-2 variants.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais , Encéfalo/metabolismo , Vacinas contra COVID-19 , Humanos , Camundongos , Camundongos Transgênicos , Glicoproteína da Espícula de Coronavírus/metabolismo
11.
Cell Host Microbe ; 29(2): 236-249.e6, 2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33357418

RESUMO

To develop a vaccine candidate against coronavirus disease 2019 (COVID-19), we generated a lentiviral vector (LV) eliciting neutralizing antibodies against the Spike glycoprotein of SARS-CoV-2. Systemic vaccination by this vector in mice, in which the expression of the SARS-CoV-2 receptor hACE2 has been induced by transduction of respiratory tract cells by an adenoviral vector, confers only partial protection despite high levels of serum neutralizing activity. However, eliciting an immune response in the respiratory tract through an intranasal boost results in a >3 log10 decrease in the lung viral loads and reduces local inflammation. Moreover, both integrative and non-integrative LV platforms display strong vaccine efficacy and inhibit lung deleterious injury in golden hamsters, which are naturally permissive to SARS-CoV-2 replication and closely mirror human COVID-19 physiopathology. Our results provide evidence of marked prophylactic effects of LV-based vaccination against SARS-CoV-2 and designate intranasal immunization as a powerful approach against COVID-19.


Assuntos
Administração Intranasal/métodos , Vacinas contra COVID-19/administração & dosagem , COVID-19/imunologia , COVID-19/prevenção & controle , SARS-CoV-2/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , Cricetinae , Feminino , Vetores Genéticos , Imunidade nas Mucosas , Imunização Secundária , Imunoglobulina A/imunologia , Lentivirus/genética , Lentivirus/imunologia , Masculino , Camundongos , Modelos Animais , Sistema Respiratório/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Carga Viral
12.
J Gen Virol ; 91(Pt 5): 1262-74, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20107019

RESUMO

The genus Hantavirus (family Bunyaviridae) includes negative-strand RNA viruses that are carried by persistently infected rodent and insectivore species. Puumala virus (PUUV), carried by bank voles (Myodes glareolus), is a pathogenic hantavirus that causes outbreaks of mild haemorrhagic fever with renal syndrome across Europe. In northern Europe, PUUV is represented by several genetic lineages that are maintained by distinct phylogroups of bank voles. The present study describes sequences of new PUUV strains recovered from northern and southern regions of Scandinavia and compares phylogenetic relationships between north-European PUUV strains and M. glareolus. This analysis revealed contradictions in phylogenetic clustering and remarkable differences in estimated divergence times between the lineages of PUUV and its host, suggesting that the established PUUV lineages did not co-diverge with the distinct phylogroups of M. glareolus that carry them at present.


Assuntos
Arvicolinae/virologia , Polimorfismo Genético , Virus Puumala/classificação , Virus Puumala/isolamento & purificação , RNA Viral/genética , Animais , Análise por Conglomerados , Europa (Continente) , Genótipo , Dados de Sequência Molecular , Filogenia , Virus Puumala/genética , Análise de Sequência de DNA
13.
J Med Virol ; 81(12): 2045-52, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19856478

RESUMO

Hantaviruses (Bunyaviridae) cause hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus (cardio)pulmonary syndrome (HCPS) in the Americas. HFRS is caused by Hantaan virus (HTNV), Seoul virus (SEOV), Dobrava virus (DOBV), Saaremaa virus (SAAV), and Puumala virus (PUUV). Of those, only HTNV is not present in Europe. In recent years, hantaviruses, described in other parts of Europe, were also detected at various locations in Hungary. To study the genetic properties of Hungarian hantaviruses in detail, sequences of the viral S and M segments were recovered from bank voles (Myodes glareolus), yellow-necked mice (Apodemus flavicollis), and striped field mice (Apodemus agrarius) trapped in the Transdanubian region. As expected, the sequences recovered belonged, respectively, to PUUV (two strains), DOBV (one strain), and SAAV (one strain). On phylogenetic trees two new Hungarian PUUV strains located within the well- supported Alpe-Adrian (ALAD) genetic lineage that included also Austrian, Slovenian, and Croatian strains. Analysis of the Hungarian SAAV and DOBV genetic variants showed host-specific clustering and also geographical clustering within each of these hantavirus species. Hungarian SAAV and DOBV strains were related most closely to strains from Slovenia (Prekmurje region). This study confirms that multiple hantaviruses can co-circulate in the same locality and can be maintained side-by-side in different rodent species.


Assuntos
Infecções por Hantavirus/virologia , Orthohantavírus/isolamento & purificação , Animais , Arvicolinae/virologia , Reservatórios de Doenças/virologia , Variação Genética , Orthohantavírus/genética , Infecções por Hantavirus/epidemiologia , Humanos , Hungria/epidemiologia , Dados de Sequência Molecular , Murinae/virologia , Filogenia , RNA Viral/genética , RNA Viral/isolamento & purificação , Análise de Sequência de RNA , Especificidade da Espécie
14.
Virol J ; 5: 4, 2008 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-18190679

RESUMO

Hantavirus genome sequences were recovered from tissue samples of Myodes rufocanus, Microtus fortis and Microtus oeconomus captured in the Baikal area of Buryatia, Russian Federation. Genetic analysis of S- and M-segment sequences of Buryatian hantavirus strains showed that Myodes-associated strains belong to Hokkaido virus (HOKV) type while Microtus-associated strains belong to Vladivostok virus (VLAV) type. On phylogenetic trees Buryatian HOKV strains were clustered together with M. rufocanus- originated strains from Japan, China and Far-East Russia (Primorsky region). Buryatian Microtus- originated strains shared a common recent ancestor with M. fortis- originated VLAV strain from Far-East Russia (Vladivostok area). Our data (i) confirm that M. rufocanus carries a hantavirus which is similar to but distinct from both Puumala virus carried by M. glareolus and Muju virus associated with M. regulus, (ii) confirm that M. fortis is the natural host for VLAV, and (iii) suggest M. oeconomus as an alternative host for VLAV.


Assuntos
Genoma Viral , Infecções por Hantavirus/veterinária , Orthohantavírus/genética , Doenças dos Roedores/virologia , Roedores/virologia , Animais , Orthohantavírus/classificação , Infecções por Hantavirus/virologia , Dados de Sequência Molecular , Filogenia , Roedores/classificação , Sibéria , Especificidade da Espécie
15.
Virol J ; 5: 113, 2008 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-18837987

RESUMO

BACKGROUND: The analysis of the nonstructural (NS) gene of the highly pathogenic (HP) H5N1 avian influenza viruses (AIV) isolated in Sweden early 2006 indicated the co-circulation of two sub-lineages of these viruses at that time. In order to complete the information on their genetic features and relation to other HP H5N1 AIVs the seven additional genes of twelve Swedish isolates were amplified in full length, sequenced, and characterized. RESULTS: The presence of two sub-lineages of HP H5N1 AIVs in Sweden in 2006 was further confirmed by the phylogenetic analysis of approximately the 95% of the genome of twelve isolates that were selected on the base of differences in geographic location, timing and animal species of origin. Ten of the analyzed viruses belonged to sub-clade 2.2.2. and grouped together with German and Danish isolates, while two 2.2.1. sub-clade viruses formed a cluster with isolates of Egyptian, Italian, Slovenian, and Nigerian origin. The revealed amino acid differences between the two sub-groups of Swedish viruses affected the predicted antigenicity of the surface glycoproteins, haemagglutinin and neuraminidase, rather than the nucleoprotein, polymerase basic protein 2, and polymerase acidic protein, the main targets of the cellular immune responses. The distinctive characteristics between members of the two subgroups were identified and described. CONCLUSION: The comprehensive genetic characterization of HP H5N1 AIVs isolated in Sweden during the spring of 2006 is reported. Our data support previous findings on the coincidental spread of multiple sub-lineage H5N1 HPAIVs via migrating aquatic birds to large distance from their origin. The detection of 2.2.1. sub-clade viruses in Sweden adds further data regarding their spread in the North of Europe in 2006. The close genetic relationship of Swedish isolates sub-clade 2.2.2. to the contemporary German and Danish isolates supports the proposition of the introduction and spread of a single variant of 2.2.2. sub-clade H5N1 avian influenza viruses in the Baltic region. The presented findings underline the importance of whole genome analysis.


Assuntos
Virus da Influenza A Subtipo H5N1/classificação , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/virologia , Animais , Aves , Análise por Conglomerados , Genoma Viral , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/epidemiologia , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência , Suécia/epidemiologia , Proteínas não Estruturais Virais/genética , Proteínas Estruturais Virais/genética
16.
Virol J ; 3: 72, 2006 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-16953877

RESUMO

Sixty one tissue samples from several rodent species trapped in five provinces of Thailand were examined for the presence of hantaviral markers by enzyme-immunoassay and immunoblotting. Four samples, all from the great bandicoot rat Bandicota indica, were confirmed positive for the hantaviral N-antigen. Two of them were trapped in Nakhon Pathom province, the other two in Nakhon Ratchasima province, approximately 250 km from the other trapping site. When analysed by RT-nested PCR, all four rodents were found positive for the hantaviral S- and M-segment nucleotide sequences. Genetic analysis revealed that the four newly described wild-type strains belong to Thailand hantavirus. On the phylogenetic trees they formed a well-supported cluster within the group of Murinae-associated hantaviruses and shared a recent common ancestor with Seoul virus.


Assuntos
Murinae/virologia , Orthohantavírus/genética , Animais , Antígenos Virais/análise , Sequência de Bases , Genoma Viral , Orthohantavírus/isolamento & purificação , Immunoblotting/métodos , Dados de Sequência Molecular , Filogenia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Tailândia
17.
Virus Res ; 90(1-2): 207-15, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12457975

RESUMO

Phylogenetic analysis of three hantaviruses: Hantaan (HTNV), Dobrava (DOBV), and the newly designated serotype/genotype Saaremaa (SAAV) and their respective hosts, rodents of genus Apodemus, reveals a discrepancy in the virus-host relationships. While all Apodemus agrarius sequences from Europe and the Far East are monophyletic, SAAV (carried by the western subspecies of A. agrarius) shared the most recent ancestor with A. flavicollis-associated DOBV virus, but not with HTNV (carried by the eastern subspecies of A. agrarius). This suggests that host switching occurred in the evolution of these hantaviruses. A likely scenario includes transmission of ancestral DOBV to the western form of A. agrarius resulting in the ecological and reproductive isolation of ancestral SAAV. Approximate time-point of the hypothetical host switching estimated from maximum likelihood (ML) phylogenetic tree, 2.7-4.0 millions years ago (MYA), is closer to the present than the expected time of split between the two Apodemus species (not later than 6.5 MYA). Taken together with other proposed cases of host switching, our observations suggest that these events might not be exceptional in the hantavirus evolution.


Assuntos
Evolução Molecular , Infecções por Hantavirus/veterinária , Muridae/virologia , Orthohantavírus/fisiologia , Filogenia , Animais , DNA Mitocondrial/genética , Orthohantavírus/classificação , Orthohantavírus/genética , Orthohantavírus/isolamento & purificação , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da Espécie
18.
J Clin Virol ; 30(3): 254-7, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15135745

RESUMO

Most human hantavirus infections in Denmark have been registered on the Fyn island with Puumala hantavirus hosted by Clethrionomys glareolus as the causative agent. To search for other known European hantaviruses in Denmark, we analyzed 101 Apodemus spp. mice trapped on the Lolland island. Genome sequences of Saaremaa hantavirus (SAAV) were recovered from one of the A. agrarius, thus suggesting SAAV presence in Denmark. We also analyzed serum samples from a patient from Lolland with a history of hantavirus-like infection, probably caused by SAAV. Thus, in addition to Puumala virus, SAAV can impose a threat for the human health in Denmark.


Assuntos
Infecções por Hantavirus/epidemiologia , Muridae/virologia , Orthohantavírus/isolamento & purificação , Doenças dos Roedores/epidemiologia , Animais , Dinamarca/epidemiologia , Orthohantavírus/classificação , Orthohantavírus/genética , Infecções por Hantavirus/veterinária , Infecções por Hantavirus/virologia , Humanos , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Doenças dos Roedores/virologia , Análise de Sequência de DNA
19.
Cell Rep ; 6(6): 1026-1036, 2014 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-24630992

RESUMO

Marburg virus (MARV) has a high fatality rate in humans, causing hemorrhagic fever characterized by massive viral replication and dysregulated inflammation. Here, we demonstrate that VP24 of MARV binds Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of nuclear transcription factor erythroid-derived 2 (Nrf2). Binding of VP24 to Keap1 Kelch domain releases Nrf2 from Keap1-mediated inhibition promoting persistent activation of a panoply of cytoprotective genes implicated in cellular responses to oxidative stress and regulation of inflammatory responses. Increased expression of Nrf2-dependent genes was demonstrated both during MARV infection and upon ectopic expression of MARV VP24. We also show that Nrf2-deficient mice can control MARV infection when compared to lethal infection in wild-type animals, indicating that Nrf2 is critical for MARV infection. We conclude that VP24-driven activation of the Nrf2-dependent pathway is likely to contribute to dysregulation of host antiviral inflammatory responses and that it ensures survival of MARV-infected cells despite these responses.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Marburgvirus/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas do Citoesqueleto/metabolismo , Células HEK293 , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Transdução de Sinais , Transfecção
20.
J Virol ; 77(16): 8793-800, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12885898

RESUMO

We previously developed a model for studies on hantavirus host adaptation and initiated genetic analysis of Puumala virus variants passaged in colonized bank voles and in cultured Vero E6 cells. With the data presented in this paper, the sequence comparison of the wild-type and Vero E6-adapted variants of Puumala virus, strain Kazan, has been completed. The only amino acid substitution that distinguished the two virus variants was found in the L protein, Ser versus Phe at position 2053. Another mutation found in the L segment, the silent transition C1053U, could result from the selection of a variant with altered L RNA folding. Nucleotide substitutions observed in individual L cDNA clones, most of them A-->G and U-->C transitions, suggested that the population of L RNA molecules is represented by quasispecies. The mutation frequency in the L segment quasispecies appeared to be similar to the corresponding values for the S and M quasispecies. Analysis of the cDNA clones with the complete S segment sequences from passage 20 confirmed our earlier conclusion that the cell-adapted genotype of the virus is represented mostly by variants with mutated S segment noncoding regions. However, the spectrum of the S segment quasispecies appeared to be changing, suggesting that, after the initial adaptation (passages 1 to 11), the viral population is still being driven by selection for variants with higher fitness.


Assuntos
Adaptação Fisiológica/genética , Mutação Puntual , Virus Puumala/fisiologia , Proteínas Virais/genética , Animais , Sequência de Bases , Chlorocebus aethiops , Primers do DNA , Conformação de Ácido Nucleico , RNA Viral , Células Vero
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA