Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Virol ; 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051278

RESUMO

Arenaviruses Lassa (LASV), Junín (JUNV) and Machupo (MACV) can cause severe and fatal diseases in humans. Although these pathogens are closely related, the host immune responses to these virus infections differs remarkably with direct implications in viral pathogenesis. LASV infection is immunosuppressive with very low level interferon response. In contrast, JUNV and MACV infections stimulate a robust IFN response in a RIG-I-dependent manner and readily activate PKR, a known host dsRNA sensor. In response to infection with RNA viruses, host non-self RNA sensors recognize viral-derived dsRNA as danger signals and initiate innate immune responses. Arenavirus nucleoproteins (NPs) contain a highly conserved exoribonuclease (ExoN) motif, through which LASV NP has been shown to degrade virus-derived immunostimulatory dsRNA in biochemical assays. In this study, we for the first time present evidence that LASV restricts dsRNA accumulation during infection. Although JUNV and MACV NPs also have the ExoN motif, dsRNA readily accumulated in infected cells and often co-localized with dsRNA sensors. Moreover, LASV co-infection diminished the dsRNA accumulation and IFN response in JUNV-infected cells. Disruption of LASV NP ExoN with mutation led to dsRNA accumulation and impaired LASV replication in minigenome systems. Importantly, both LASV NP and RNA polymerase L protein were required to diminish dsRNA accumulation and IFN response in JUNV infection. For the first time, we discovered a collaboration between LASV NP ExoN and L protein in limiting dsRNA accumulation. Our new findings provide mechanistic insights into the differential host innate immune responses to highly pathogenic arenavirus infections.SignificanceArenavirus NPs contain a highly conserved DEDDh ExoN motif, through which LASV NP degrades virus-derived, immunostimulatory dsRNA in biochemical assays to eliminate the danger signal and inhibit innate immune response. Nevertheless, the function of NP ExoN in arenavirus infection remains to be defined. In this study, we discovered that LASV potently restricts dsRNA accumulation during infection and minigenome replication. In contrast, although the NPs of JUNV and MACV also harbor the ExoN motif, dsRNA readily formed during JUNV and MACV infections accompanied by IFN and PKR responses. Interestingly, LASV NP alone was not sufficient to limit dsRNA accumulation. Instead, both LASV NP and L protein were required to restrict immunostimulatory dsRNA accumulation. Our findings provide novel and important insights to the mechanism for the distinct innate immune response to these highly pathogenic arenaviruses and open new directions for future studies.

2.
Cell Rep ; 30(2): 308-319.e5, 2020 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-31940478

RESUMO

Fruit bats are suspected to be natural hosts of filoviruses, including Ebola virus (EBOV) and Marburg virus (MARV). Interestingly, however, previous studies suggest that these viruses have different tropisms depending on the bat species. Here, we show a molecular basis underlying the host-range restriction of filoviruses. We find that bat-derived cell lines FBKT1 and ZFBK13-76E show preferential susceptibility to EBOV and MARV, respectively, whereas the other bat cell lines tested are similarly infected with both viruses. In FBKT1 and ZFBK13-76E, unique amino acid (aa) sequences are found in the Niemann-Pick C1 (NPC1) protein, one of the cellular receptors interacting with the filovirus glycoprotein (GP). These aa residues, as well as a few aa differences between EBOV and MARV GPs, are crucial for the differential susceptibility to filoviruses. Taken together, our findings indicate that the heterogeneity of bat NPC1 orthologs is an important factor controlling filovirus species-specific host tropism.

3.
Vaccine ; 37(45): 6824-6831, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31561999

RESUMO

Lassa virus (LASV), the causative agent of Lassa fever (LF), was first identified in 1969. Since then, outbreaks in the endemic countries of Nigeria, Liberia, and Sierra Leone occur on an annual basis resulting in a case-fatality rate of 15-70% in hospitalized patients. There is currently no licensed vaccine and there are limited animal models to test vaccine efficacy. An estimated 37.7 million people are at risk of contracting LASV; therefore, there is an urgent need for the development of a safe, effective vaccine against LASV infection. The LF endemic countries are also inflicted with HIV, Ebola, and malaria infections. The safety in immunocompromised populations must be considered in LASV vaccine development. The novel adenovirus vector-based platform, Ad5 (E1-,E2b-) has been used in clinical trial protocols for treatment of immunocompromised individuals, has been shown to exhibit high stability, low safety risk in humans, and induces a strong cell-mediated and pro-inflammatory immune response even in the presence of pre-existing adenovirus immunity. To this nature, our lab has developed an Ad5 (E1-,E2b-) vector-based vaccine expressing the LASV-NP or LASV-GPC. We found that guinea pigs vaccinated with two doses of Ad5 (E1-,E2b-) LASV-NP and Ad5 (E1-,E2b-) LASV-GPC were protected against lethal LASV challenge. The Ad5 (E1-,E2b-) LASV-NP and LASV-GPC vaccine represents a potential vaccine candidate against LF.

4.
mSphere ; 4(5)2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31554720

RESUMO

Lassa virus (LASV), a member of the family Arenaviridae, is the causative agent of Lassa fever. Lassa virus is endemic in West African countries, such as Nigeria, Guinea, Liberia, and Sierra Leone, and causes outbreaks annually. Lassa fever onset begins with "flu-like" symptoms and may develop into lethal hemorrhagic disease in severe cases. Although Lassa virus is one of the most alarming pathogens from a public health perspective, there are few licensed vaccines or therapeutics against Lassa fever. The fact that animal models are limited and the fact that mostly laboratory-derived viruses are used for studies limit the successful development of countermeasures. In this study, we demonstrated that the LASV isolate LF2384-NS-DIA-1 (LF2384), which was directly isolated from a serum sample from a fatal human Lassa fever case in the 2012 Sierra Leone outbreak, causes uniformly lethal infection in outbred Hartley guinea pigs without virus-host adaptation. This is the first report of a clinically isolated strain of LASV causing lethal infection in outbred guinea pigs. This novel guinea pig model of Lassa fever may contribute to Lassa fever research and the development of vaccines and therapeutics.IMPORTANCE Lassa virus, the causative agent of Lassa fever, is a zoonotic pathogen causing annual outbreaks in West African countries. Human patients can develop lethal hemorrhagic fever in severe cases. Although Lassa virus is one of the most alarming pathogens from a public health perspective, there are few available countermeasures, such as antiviral drugs or vaccines. Moreover, the fact that animal models are not readily accessible and the fact that mostly laboratory viruses, which have been passaged many times after isolation, are used for studies further limits the successful development of countermeasures. In this study, we demonstrate that a human isolate of Lassa virus causes lethal infection uniformly in Hartley guinea pigs. This novel animal model of Lassa fever may contribute to Lassa fever research and the development of vaccines and therapeutics.


Assuntos
Modelos Animais de Doenças , Febre Lassa/mortalidade , Febre Lassa/veterinária , Vírus Lassa/patogenicidade , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Cobaias , Humanos , Vírus Lassa/isolamento & purificação , Dose Letal Mediana , Carga Viral
5.
Curr Opin Virol ; 37: 118-122, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31479989

RESUMO

Lassa virus (LASV) is endemic in West Africa, causing an estimated 100000-300000 new infections and up to 5000-10000 deaths yearly. There are no vaccines and therapeutics are extremely limited. Typical case fatality rates are ∼1%, although a recent 2018 Nigerian outbreak featured an unprecedented 25.4% case fatality rate. Survivors of infection suffer a lifetime of sequelae with sudden onset sensorineural hearing loss (SNHL) being the most prevalent. The cause of this hearing loss remains unknown, and there is a critical need for further research on its mechanisms and potential therapeutics. The objective of this review is to outline the only currently available small animal model for LASV-induced hearing loss and to identify potential surrogate models.

6.
Sci Rep ; 9(1): 1158, 2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30718752

RESUMO

Two novel influenza A virus-like genomes were detected in fruit bats in Central and South America. However, the biological properties of these bat-derived influenza viruses (BatIVs) are still largely unknown since infectious viral particles have never been isolated from the infected host species. In this study, a reverse genetics approach was used to generate infectious BatIV particles entirely from plasmids encoding full-length sequences in eight gene segments. We inoculated BatIV particles into various cell cultures including bat-derived cell lines and found that BatIVs infected particular bat-derived cells efficiently but not the other cell lines tested. Reassortant viruses between the two BatIVs were also successfully generated and their replication in the susceptible bat cell lines was confirmed. These findings suggest a limited host range and reassortment potential of BatIVs in nature, providing fundamental information for understanding of the ecology of BatIVs.

7.
Sci Rep ; 9(1): 573, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679679

RESUMO

Recently, bat adenoviruses (BtAdVs) of genus Mastadenovirus have been isolated from various bat species, some of them displaying a wide host range in cell culture. In this study, we isolated two BtAdVs from Japanese wild microbats. While one isolate was classified as Bat mastadenovirus A, the other was phylogenetically independent of other BtAdVs. It was rather related to, but serologically different from, canine adenoviruses. We propose that the latter, isolated from Asian parti-colored bat, should be assigned to a novel species of Bat mastadenovirus. Both isolates replicated in various mammalian cell lines, implying their wide cell tropism. To gain insight into cell tropism of these BtAdVs, we investigated the coxsackievirus and adenovirus receptor (CXADR) for virus entry to the cells. We prepared CXADR-knockout canine kidney cells and found that replication of BtAdVs was significantly hampered in these cells. For confirmation, their replication in canine CXADR-addback cells was rescued to the levels with the original cells. We also found that viral replication was corrected in human or bat CXADR-transduced cells to similar levels as in canine CXADR-addback cells. These results suggest that BtAdVs were able to use several mammalian-derived CXADRs as entry factors.

8.
Front Microbiol ; 9: 1751, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30123198

RESUMO

The family Arenaviridae is divided into three genera: Mammarenavirus, Reptarenavirus, and Hartmanivirus. The Mammarenaviruses contain viruses responsible for causing human hemorrhagic fever diseases including New World viruses Junin, Machupo, Guanarito, Sabia, and Chapare virus and Old World viruses Lassa, and Lujo virus. These two groups of arenaviruses share the same genome organization composed of two ambisense RNA segments. These segments contain four open reading frames that encode for four proteins: the nucleoprotein, glycoprotein precursor, L protein, and Z. Despite their genome similarities, these groups exhibit marked differences in their replication life cycles. This includes differences in attachment, entry, and immune evasion. By understanding the intricacy of replication in each of these viral species we can work to develop counter measures against human diseases. This includes the development of vaccines and antivirals for these emerging viral threats. Currently only the vaccine against Junin virus, Candid#1, is in use as well as Ribavirin for treatment of Lassa Fever. In addition, small molecule inhibitors can be developed to target various aspects of the virus life cycle. In these ways an understanding of the arenavirus replication cycle can be used to alleviate the mortality and morbidity of these infections worldwide.

9.
J Infect Dis ; 218(suppl_5): S397-S402, 2018 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-30010949

RESUMO

Niemann-Pick C1 (NPC1), a host receptor involved in the envelope glycoprotein (GP)-mediated entry of filoviruses into cells, is believed to be a major determinant of cell susceptibility to filovirus infection. It is known that proteolytically digested Ebola virus (EBOV) GP interacts with 2 protruding loops in domain C of NPC1. Using previously published structural data and the National Center for Biotechnology Information Single-Nucleotide Polymorphism (SNP) database, we identified 10 naturally occurring missense SNPs in human NPC1. To investigate whether these SNPs affect cell susceptibility to filovirus infection, we generated Vero E6 cell lines stably expressing NPC1 with SNP substitutions and compared their susceptibility to vesicular stomatitis virus pseudotyped with filovirus GPs and infectious EBOV. We found that some of the substitutions resulted in reduced susceptibility to filoviruses, as indicated by the lower titers and smaller plaque/focus sizes of the viruses. Our data suggest that human NPC1 SNPs may likely affect host susceptibility to filoviruses.


Assuntos
Proteínas de Transporte/genética , Ebolavirus/patogenicidade , Doença pelo Vírus Ebola/genética , Doença pelo Vírus Ebola/virologia , Glicoproteínas de Membrana/genética , Polimorfismo de Nucleotídeo Único/genética , Animais , Linhagem Celular , Células HEK293 , Humanos , Receptores Virais/metabolismo , Células Vero , Proteínas do Envelope Viral/metabolismo , Internalização do Vírus
10.
PLoS Pathog ; 14(1): e1006848, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29338048

RESUMO

Cell surface receptors for phosphatidylserine contribute to the entry of Ebola virus (EBOV) particles, indicating that the presence of phosphatidylserine in the envelope of EBOV is important for the internalization of EBOV particles. Phosphatidylserine is typically distributed in the inner layer of the plasma membrane in normal cells. Progeny virions bud from the plasma membrane of infected cells, suggesting that phosphatidylserine is likely flipped to the outer leaflet of the plasma membrane in infected cells for EBOV virions to acquire it. Currently, the intracellular dynamics of phosphatidylserine during EBOV infection are poorly understood. Here, we explored the role of XK-related protein (Xkr) 8, which is a scramblase responsible for exposure of phosphatidylserine in the plasma membrane of apoptotic cells, to understand its significance in phosphatidylserine-dependent entry of EBOV. We found that Xkr8 and transiently expressed EBOV glycoprotein GP often co-localized in intracellular vesicles and the plasma membrane. We also found that co-expression of GP and viral major matrix protein VP40 promoted incorporation of Xkr8 into ebolavirus-like particles (VLPs) and exposure of phosphatidylserine on their surface, although only a limited amount of phosphatidylserine was exposed on the surface of the cells expressing GP and/or VP40. Downregulating Xkr8 or blocking caspase-mediated Xkr8 activation did not affect VLP production, but they reduced the amount of phosphatidylserine on the VLPs and their uptake in recipient cells. Taken together, our findings indicate that Xkr8 is trafficked to budding sites via GP-containing vesicles, is incorporated into VLPs, and then promote the entry of the released EBOV to cells in a phosphatidylserine-dependent manner.


Assuntos
Ebolavirus/fisiologia , Interações Hospedeiro-Patógeno , Fosfatidilserinas/metabolismo , Proteínas de Transferência de Fosfolipídeos/fisiologia , Vírion/metabolismo , Animais , Células HEK293 , Doença pelo Vírus Ebola/metabolismo , Doença pelo Vírus Ebola/virologia , Humanos , Células Vero , Proteínas do Core Viral/metabolismo , Liberação de Vírus
11.
PLoS One ; 12(10): e0186450, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29040311

RESUMO

It has been proposed that some non-retroviral RNA virus genes are integrated into vertebrate genomes. Endogenous filovirus-like elements (EFLs) have been discovered in some mammalian genomes. However, their potential roles in ebolavirus infection are unclear. A filovirus VP35-like element (mlEFL35) is found in the little brown bat (Myotis lucifugus) genome. Putative mlEFL35-derived protein (mlEFL35p) contains nearly full-length amino acid sequences corresponding to ebolavirus VP35. Ebola virus VP35 has been shown to bind double-stranded RNA, leading to inhibition of type I interferon (IFN) production, and is also known as a viral polymerase cofactor that is essential for viral RNA transcription/replication. In this study, we transiently expressed mlEFL35p in human kidney cells and investigated its biological functions. We first found that mlEFL35p was coimmunoprecipitated with itself and ebolavirus VP35s but not with the viral nucleoprotein. Then the biological functions of mlEFL35p were analyzed by comparing it to ebolavirus VP35s. We found that the expression of mlEFL35p significantly inhibited human IFN-ß promoter activity as well as VP35s. By contrast, expression of mlEFL35p did not support viral RNA transcription/replication and indeed slightly decrease the reporter gene expression in a minigenome assay. These results suggest that mlEFL35p potentially acts as an IFN antagonist but not a polymerase cofactor.


Assuntos
Ebolavirus/genética , Interações Hospedeiro-Patógeno , Interferon beta/antagonistas & inibidores , Nucleoproteínas/genética , RNA de Cadeia Dupla/genética , Proteínas do Core Viral/genética , Sequência de Aminoácidos , Animais , Quirópteros/virologia , Ebolavirus/isolamento & purificação , Ebolavirus/metabolismo , Expressão Gênica , Genes Reporter , Células HEK293 , Humanos , Interferon beta/genética , Interferon beta/imunologia , Luciferases/genética , Luciferases/metabolismo , Nucleoproteínas/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , RNA de Cadeia Dupla/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Proteínas do Core Viral/metabolismo , Replicação Viral
12.
PLoS One ; 12(8): e0182228, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28787440

RESUMO

Highly pathogenic avian influenza viruses (HPAIVs) of H5 subtype have persistently caused outbreaks in domestic poultry and wild birds worldwide and sporadically infected humans. Rapid and accurate diagnosis is one of the key strategies for the control of H5 HPAIVs. However, the sensitivity of the diagnosis of H5 HPAIVs has gradually reduced due to extensive antigenic variation during their evolution. Particularly, the previously developed immunochromatographic diagnosis kit for H5 viruses, Linjudge Flu A/H5, exhibits reduced detection of H5 HPAIVs isolated in recent years. In the present study, we established a new advanced H5 rapid immunochromatographic detection kit (New Linjudge Flu A/H5) by a combination of two anti-H5 hemagglutinin monoclonal antibodies, A64/1 previously applied in the Linjudge Flu A/H5 and A32/2, a novel monoclonal antibody generated from a clade 2.3.4.4 H5 HPAIV. The new kit broadly detected all classical and recent H5 influenza viruses and showed a higher specificity and sensitivity than the original Linjudge Flu A/H5 with recently circulating H5 HPAIVs. Furthermore, the applicability of the New Linjudge Flu A/H5 was demonstrated by detecting antigens from the swabs and tissue homogenates of naturally infected birds and experimentally infected chickens with H5N6 HPAIVs belonging to the genetic clade 2.3.4.4. Our study, therefore, can provide an effective point-of-care rapid antigen detection kit for the surveillance of H5 avian influenza viruses and as a prompt countermeasure against the current widespread of the clade 2.3.4.4 H5 HPAIVs in domestic and wild birds.


Assuntos
Cromatografia de Afinidade , Glicoproteínas de Hemaglutininação de Vírus da Influenza/análise , Vírus da Influenza A/imunologia , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/diagnóstico , Animais , Anseriformes/imunologia , Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Galinhas/imunologia , Cromatografia de Afinidade/instrumentação , Humanos , Vírus da Influenza A/genética , Influenza Aviária/imunologia , Kit de Reagentes para Diagnóstico , Sensibilidade e Especificidade
13.
Ticks Tick Borne Dis ; 8(1): 103-111, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27769656

RESUMO

Ticks harbour various microorganisms, some of which act as pathogens of humans and animals. The recent advancement of genome sequencing technologies revealed that a wide range of previously unrecognised microorganisms exist in ticks. Continuous cell lines established from ticks could play a key role in the isolation of such microorganisms; however, tick cells themselves have been known to harbour symbiotic microorganisms. The present study aimed to characterise putative RNA viral sequences detected in the culture supernatant of one of the most frequently used tick cell lines, ISE6, which was derived from embryos of the blacklegged tick Ixodes scapularis. Viral particles purified from the culture supernatant were used for RNA extraction, followed by Illumina sequencing. The reads were de novo assembled and the resulting contigs were annotated by tBLASTx search. The results suggested that there were at least five putative viral sequences of four phylogenetically distinct lineages in ISE6 cells. The predominant viral sequence found in ISE6 cells, designated I. scapularis iflavirus, was a member of the family Iflaviridae, which is an arthropod-infecting virus group. We also identified L and M segments of the family Bunyaviridae, which could not be classified into any of the five known genera, and a potential capsid protein related to Drosophila A virus. In addition to these previously unrecognised viruses, ISE6 was revealed to harbour a putative genome sequence of I. scapularis-associated virus-1, which was reported in a recent metagenomic study of I. scapularis itself. All the five putative viral sequences were detected by RT-PCR in both ISE6 cells and the culture supernatant. Electron microscopic analysis showed the existence of spherical virions with a varying diameter of 50-70nm in the culture supernatant of ISE6 cells. Further studies are required to investigate the potential roles of ISE6-associated viruses in ticks.


Assuntos
Ixodes/citologia , Orthobunyavirus/genética , Picornaviridae/genética , RNA Viral/isolamento & purificação , Animais , Linhagem Celular , Filogenia
14.
PLoS Pathog ; 12(12): e1006139, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28036370

RESUMO

Antibody-dependent enhancement (ADE) of Ebola virus (EBOV) infection has been demonstrated in vitro, raising concerns about the detrimental potential of some anti-EBOV antibodies. ADE has been described for many viruses and mostly depends on the cross-linking of virus-antibody complexes to cell surface Fc receptors, leading to enhanced infection. However, little is known about the molecular mechanisms underlying this phenomenon. Here we show that Fcγ-receptor IIa (FcγRIIa)-mediated intracellular signaling through Src family protein tyrosine kinases (PTKs) is required for ADE of EBOV infection. We found that deletion of the FcγRIIa cytoplasmic tail abolished EBOV ADE due to decreased virus uptake into cellular endosomes. Furthermore, EBOV ADE, but not non-ADE infection, was significantly reduced by inhibition of the Src family protein PTK pathway, which was also found to be important to promote phagocytosis/macropinocytosis for viral uptake into endosomes. We further confirmed a significant increase of the Src phosphorylation mediated by ADE. These data suggest that antibody-EBOV complexes bound to the cell surface FcγRIIa activate the Src signaling pathway that leads to enhanced viral entry into cells, providing a novel perspective for the general understanding of ADE of virus infection.


Assuntos
Anticorpos Facilitadores/imunologia , Doença pelo Vírus Ebola/imunologia , Receptores de IgG/imunologia , Transdução de Sinais/imunologia , Quinases da Família src/imunologia , Animais , Anticorpos Antivirais/imunologia , Técnicas de Silenciamento de Genes , Células HEK293 , Doença pelo Vírus Ebola/metabolismo , Humanos , Células Jurkat , Células K562 , Células Vero , Internalização do Vírus
15.
Sci Rep ; 6: 20514, 2016 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-26861827

RESUMO

During the latest outbreak of Ebola virus disease in West Africa, monoclonal antibody therapy (e.g., ZMapp) was utilized to treat patients. However, due to the antigenic differences among the five ebolavirus species, the current therapeutic monoclonal antibodies are only effective against viruses of the species Zaire ebolavirus. Although this particular species has indeed caused the majority of human infections in Central and, recently, West Africa, other ebolavirus species (e.g., Sudan ebolavirus and Bundibugyo ebolavirus) have also repeatedly caused outbreaks in Central Africa and thus should not be neglected in the development of countermeasures against ebolaviruses. Here we report the generation of an ebolavirus glycoprotein-specific monoclonal antibody that effectively inhibits cellular entry of representative isolates of all known ebolavirus species in vitro and show its protective efficacy in mouse models of ebolavirus infections. This novel neutralizing monoclonal antibody targets a highly conserved internal fusion loop in the glycoprotein molecule and prevents membrane fusion of the viral envelope with cellular membranes. The discovery of this highly cross-neutralizing antibody provides a promising option for broad-acting ebolavirus antibody therapy and will accelerate the design of improved vaccines that can selectively elicit cross-neutralizing antibodies against multiple species of ebolaviruses.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , Doença pelo Vírus Ebola/tratamento farmacológico , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Modelos Animais de Doenças , Ebolavirus/metabolismo , Epitopos/química , Epitopos/imunologia , Feminino , Doença pelo Vírus Ebola/mortalidade , Doença pelo Vírus Ebola/veterinária , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Receptor de Interferon alfa e beta/deficiência , Receptor de Interferon alfa e beta/genética , Alinhamento de Sequência , Taxa de Sobrevida , Células Vero , Internalização do Vírus/efeitos dos fármacos
16.
Virology ; 488: 43-50, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26605499

RESUMO

Recently found bat-derived influenza viruses (BatIVs) have hemagglutinin (HA) and neuraminidase (NA) gene segments distinct from those of previously known influenza A viruses. However, pathogenicities of these BatIVs remain unknown since infectious virus strains have not been isolated yet. To gain insight into the biological properties of BatIVs, we generated vesicular stomatitis viruses (VSVs) pseudotyped with the BatIV HA and NA. We found that VSVs pseudotyped with BatIV HAs and NAs efficiently infected particular bat cell lines but not those derived from primates, and that proteolytic cleavage with a trypsin-like protease was necessary for HA-mediated virus entry. Treatment of the susceptible bat cells with some enzymes and inhibitors revealed that BatIV HAs might recognize some cellular glycoproteins as receptors rather than the sialic acids used for the other known influenza viruses. These data provide fundamental information on the mechanisms underlying the cellular entry and host restriction of BatIVs.


Assuntos
Quirópteros/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Neuraminidase/metabolismo , Orthomyxoviridae/isolamento & purificação , Vesiculovirus/fisiologia , Internalização do Vírus , Animais , Linhagem Celular , Vetores Genéticos , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Neuraminidase/genética , Receptores Virais/metabolismo , Vesiculovirus/genética
17.
PLoS One ; 10(9): e0137989, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26368015

RESUMO

Two highly pathogenic avian influenza virus strains, A/duck/Hokkaido/WZ83/2010 (H5N1) (WZ83) and A/duck/Hokkaido/WZ101/2010 (H5N1) (WZ101), which were isolated from wild ducks in Japan, were found to be genetically similar, with only two amino acid differences in their M1 and PB1 proteins at positions 43 and 317, respectively. We found that both WZ83 and WZ101 caused lethal infection in chickens but WZ101 killed them more rapidly than WZ83. Interestingly, ducks experimentally infected with WZ83 showed no or only mild clinical symptoms, whereas WZ101 was highly lethal. We then generated reassortants between these viruses and found that exchange of the M gene segment completely switched the pathogenic phenotype in both chickens and ducks, indicating that the difference in the pathogenicity for these avian species between WZ83 and WZ101 was determined by only a single amino acid in the M1 protein. It was also found that WZ101 showed higher pathogenicity than WZ83 in mice and that WZ83, whose M gene was replaced with that of WZ101, showed higher pathogenicity than wild-type WZ83, although this reassortant virus was not fully pathogenic compared to wild-type WZ101. These results suggest that the amino acid at position 43 of the M1 protein is one of the factors contributing to the pathogenicity of H5N1 highly pathogenic avian influenza viruses in both avian and mammalian hosts.


Assuntos
Substituição de Aminoácidos , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/patogenicidade , Mutação de Sentido Incorreto , Infecções por Orthomyxoviridae/genética , Proteínas da Matriz Viral/genética , Animais , Embrião de Galinha , Patos , Camundongos
18.
Virus Genes ; 51(1): 57-68, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26036326

RESUMO

Migratory water birds are the natural reservoir of influenza A viruses. H5 and H7 influenza viruses are isolated over the world and also circulate among poultry in Asia. In 2010, two H5N1 highly pathogenic avian influenza viruses (HPAIVs) were isolated from fecal samples of water birds on the flyway of migration from Siberia, Russia to the south in Hokkaido, Japan. H7N9 viruses are sporadically isolated from humans and circulate in poultry in China. To monitor whether these viruses have spread in the wild bird population, we conducted virological surveillance of avian influenza in migratory water birds in autumn from 2010 to 2014. A total of 8103 fecal samples from migratory water birds were collected in Japan and Mongolia, and 350 influenza viruses including 13 H5 and 19 H7 influenza viruses were isolated. A phylogenetic analysis revealed that all isolates are genetically closely related to viruses circulating among wild water birds. The results of the antigenic analysis indicated that the antigenicity of viruses in wild water birds is highly stable despite their nucleotide sequence diversity but is distinct from that of HPAIVs recently isolated in Asia. The present results suggest that HPAIVs and Chinese H7N9 viruses were not predominantly circulating in migratory water birds; however, continued monitoring of H5 and H7 influenza viruses both in domestic and wild birds is recommended for the control of avian influenza.


Assuntos
Antígenos Virais/análise , Antígenos Virais/genética , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Influenza Aviária/virologia , Animais , Aves , Análise por Conglomerados , Fezes/virologia , Variação Genética , Japão , Dados de Sequência Molecular , Mongólia , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Homologia de Sequência
19.
J Virol ; 89(12): 6481-93, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25855742

RESUMO

UNLABELLED: Multiple host molecules are known to be involved in the cellular entry of filoviruses, including Ebola virus (EBOV); T-cell immunoglobulin and mucin domain 1 (TIM-1) and Niemann-Pick C1 (NPC1) have been identified as attachment and fusion receptors, respectively. However, the molecular mechanisms underlying the entry process have not been fully understood. We found that TIM-1 and NPC1 colocalized and interacted in the intracellular vesicles where EBOV glycoprotein (GP)-mediated membrane fusion occurred. Interestingly, a TIM-1-specific monoclonal antibody (MAb), M224/1, prevented GP-mediated membrane fusion and also interfered with the binding of TIM-1 to NPC1, suggesting that the interaction between TIM-1 and NPC1 is important for filovirus membrane fusion. Moreover, MAb M224/1 efficiently inhibited the cellular entry of viruses from all known filovirus species. These data suggest a novel mechanism underlying filovirus membrane fusion and provide a potential cellular target for antiviral compounds that can be universally used against filovirus infections. IMPORTANCE: Filoviruses, including Ebola and Marburg viruses, cause rapidly fatal diseases in humans and nonhuman primates. There are currently no approved vaccines or therapeutics for filovirus diseases. In general, the cellular entry step of viruses is one of the key mechanisms to develop antiviral strategies. However, the molecular mechanisms underlying the entry process of filoviruses have not been fully understood. In this study, we demonstrate that TIM-1 and NPC1, which serve as attachment and fusion receptors for filovirus entry, interact in the intracellular vesicles where Ebola virus GP-mediated membrane fusion occurs and that this interaction is important for filovirus infection. We found that filovirus infection and GP-mediated membrane fusion in cultured cells were remarkably suppressed by treatment with a TIM-1-specific monoclonal antibody that interfered with the interaction between TIM-1 and NPC1. Our data provide new insights for the development of antiviral compounds that can be universally used against filovirus infections.


Assuntos
Ebolavirus/fisiologia , Receptores Virais/metabolismo , Internalização do Vírus , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Linhagem Celular , Cercopithecus , Humanos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Mapeamento de Interação de Proteínas , Receptores Virais/genética , Análise de Sequência de DNA
20.
J Infect Dis ; 212 Suppl 2: S101-8, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25786916

RESUMO

Fruit bats are suspected to be a natural reservoir of filoviruses, including Ebola and Marburg viruses. Using an enzyme-linked immunosorbent assay based on the viral glycoprotein antigens, we detected filovirus-specific immunoglobulin G antibodies in 71 of 748 serum samples collected from migratory fruit bats (Eidolon helvum) in Zambia during 2006-2013. Although antibodies to African filoviruses (eg, Zaire ebolavirus) were most prevalent, some serum samples showed distinct specificity for Reston ebolavirus, which that has thus far been found only in Asia. Interestingly, the transition of filovirus species causing outbreaks in Central and West Africa during 2005-2014 seemed to be synchronized with the change of the serologically dominant virus species in these bats. These data suggest the introduction of multiple species of filoviruses in the migratory bat population and point to the need for continued surveillance of filovirus infection of wild animals in sub-Saharan Africa, including hitherto nonendemic countries.


Assuntos
Quirópteros/virologia , Infecções por Filoviridae/epidemiologia , Infecções por Filoviridae/virologia , Filoviridae/imunologia , África/epidemiologia , Animais , Anticorpos Antivirais/sangue , Ásia/epidemiologia , Linhagem Celular , Quirópteros/sangue , Quirópteros/imunologia , Surtos de Doenças , Ebolavirus/imunologia , Feminino , Infecções por Filoviridae/sangue , Infecções por Filoviridae/imunologia , Glicoproteínas/imunologia , Células HEK293 , Doença pelo Vírus Ebola/sangue , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/imunologia , Doença pelo Vírus Ebola/virologia , Humanos , Imunoglobulina G/sangue , Masculino , Prevalência , Proteínas Virais/imunologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA