Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cell Rep ; 28(12): 3032-3046.e6, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31533029

RESUMO

Zaire ebolavirus (EBOV) VP35 protein is a suppressor of type I interferon (IFN) production, an inhibitor of dendritic cell maturation, and a putative virulence determinant. Here, a recombinant EBOV encoding a mutant VP35 virus (VP35m) is demonstrated to activate RIG-I-like receptor signaling and innate antiviral pathways. When inoculated into cynomolgus macaques, VP35m exhibits dramatic attenuation as compared to wild-type EBOV (wtEBOV), with 20 or 300 times the standard 100% lethal challenge dose not causing EBOV disease (EVD). Further, VP35m infection, despite limited replication in vivo, activates antigen presentation and innate immunity pathways and elicits increased frequencies of proliferating memory T cells and B cells and production of anti-EBOV antibodies. Upon wtEBOV challenge, VP35m-immunized animals survive, exhibiting host responses consistent with an orderly immune response and the absence of excessive inflammation. These data demonstrate that VP35 is a critical EBOV immune evasion factor and provide insights into immune mechanisms of EBOV control.

2.
Cell ; 178(4): 1004-1015.e14, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31398326

RESUMO

Lassa virus (LASV) causes hemorrhagic fever and is endemic in West Africa. Protective antibody responses primarily target the LASV surface glycoprotein (GPC), and GPC-B competition group antibodies often show potent neutralizing activity in humans. However, which features confer potent and broadly neutralizing antibody responses is unclear. Here, we compared three crystal structures of LASV GPC complexed with GPC-B antibodies of varying neutralization potency. Each GPC-B antibody recognized an overlapping epitope involved in binding of two adjacent GPC monomers and preserved the prefusion trimeric conformation. Differences among GPC-antibody interactions highlighted specific residues that enhance neutralization. Using structure-guided amino acid substitutions, we increased the neutralization potency and breadth of these antibodies to include all major LASV lineages. The ability to define antibody residues that allow potent and broad neutralizing activity, together with findings from analyses of inferred germline precursors, is critical to develop potent therapeutics and for vaccine design and assessment.

3.
Curr Opin Virol ; 37: 97-104, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31401518

RESUMO

Serum from convalescent Lassa fever patients was previously shown to be ineffective as a source of protective antibodies in some early studies. Subsequently, monoclonal antibodies (MAbs) to the Lassa virus (LASV) glycoprotein produced by memory B cells of West African patients who survived Lassa fever were identified. Development of MAbs as potential Lassa immunotherapeutics was facilitated by structural studies and mutational analyses that identified protective epitopes on the prefusion form of the LASV glycoprotein. Human mAbs were screened for reactivity to different neutralizing epitopes, potency, and broad reactivity against multiple lineages of LASV. MAbs were downselected in a guinea pig model of Lassa fever. A cocktail of three human MAbs designated Arevirumab-3 rescued 100% of Cynomolgus macaques at advanced stages of disease more than a week post-infection. Antibody therapeutics may be further developed in clinical trials in endemic areas potentially offering a key treatment option for Lassa fever.

4.
Lancet Infect Dis ; 19(9): 925-927, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31300333
5.
Sci Rep ; 9(1): 7329, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-31065012

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

6.
Sci Rep ; 9(1): 7755, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31123310

RESUMO

Crimean-Congo hemorrhagic fever virus (CCHFV), a tick-borne bunyavirus, can cause a life-threatening hemorrhagic syndrome in humans but not in its animal host. The virus is widely distributed throughout southeastern Europe, the Middle East, Africa, and Asia. Disease management has proven difficult and there are no broadly licensed vaccines or therapeutics. Recombinant vesicular stomatitis viruses (rVSV) expressing foreign glycoproteins (GP) have shown promise as experimental vaccines for several viral hemorrhagic fevers. Here, we developed and assessed a replication competent rVSV vector expressing the CCHFV glycoprotein precursor (GPC), which encodes CCHFV structural glycoproteins. This construct drives strong expression of CCHFV-GP, in vitro. Using these vectors, we vaccinated STAT-1 knock-out mice, an animal model for CCHFV. The vector was tolerated and 100% efficacious against challenge from a clinical strain of CCHFV. Anti-CCHFV-GP IgG and neutralizing antibody titers were observed in surviving animals. This study demonstrates that a rVSV expressing only the CCHFV-GP has the potential to serve as a replication competent vaccine platform against CCHF infections.

7.
Cell Host Microbe ; 25(1): 49-58.e5, 2019 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-30629918

RESUMO

Recent and ongoing outbreaks of Ebola virus disease (EVD) underscore the unpredictable nature of ebolavirus reemergence and the urgent need for antiviral treatments. Unfortunately, available experimental vaccines and immunotherapeutics are specific for a single member of the Ebolavirus genus, Ebola virus (EBOV), and ineffective against other ebolaviruses associated with EVD, including Sudan virus (SUDV) and Bundibugyo virus (BDBV). Here we show that MBP134AF, a pan-ebolavirus therapeutic comprising two broadly neutralizing human antibodies (bNAbs), affords unprecedented effectiveness and potency as a therapeutic countermeasure to antigenically diverse ebolaviruses. MBP134AF could fully protect ferrets against lethal EBOV, SUDV, and BDBV infection, and a single 25-mg/kg dose was sufficient to protect NHPs against all three viruses. The development of MBP134AF provides a successful model for the rapid discovery and translational advancement of immunotherapeutics targeting emerging infectious diseases.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Ebolavirus/patogenicidade , Furões/virologia , Doença pelo Vírus Ebola/imunologia , Doença pelo Vírus Ebola/prevenção & controle , Bem-Estar do Animal , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/isolamento & purificação , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/administração & dosagem , Linhagem Celular , Cercopithecus aethiops , Modelos Animais de Doenças , Feminino , Filoviridae/imunologia , Infecções por Filoviridae/imunologia , Infecções por Filoviridae/prevenção & controle , Infecções por Filoviridae/virologia , Glicoproteínas/imunologia , Cobaias , Células HEK293 , Doença pelo Vírus Ebola/virologia , Humanos , Células Matadoras Naturais , Macaca , Macaca fascicularis , Masculino , Primatas , Análise de Sobrevida , Resultado do Tratamento , Proteínas Virais/imunologia
8.
J Infect Dis ; 218(suppl_5): S486-S495, 2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-30476250

RESUMO

The domestic ferret is a uniformly lethal model of infection for 3 species of Ebolavirus known to be pathogenic in humans. Reagents to systematically analyze the ferret host response to infection are lacking; however, the recent publication of a draft ferret genome has opened the potential for transcriptional analysis of ferret models of disease. In this work, we present comparative analysis of longitudinally sampled blood taken from ferrets and nonhuman primates infected with lethal doses of the Makona variant of Zaire ebolavirus. Strong induction of proinflammatory and prothrombotic signaling programs were present in both ferrets and nonhuman primates, and both transcriptomes were similar to previously published datasets of fatal cases of human Ebola virus infection.

9.
Expert Opin Drug Discov ; 13(11): 1027-1040, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30269599

RESUMO

INTRODUCTION: Small animal models have played a critical role in understanding the pathogenesis and transmission of disease caused by filoviruses. Notably, small animals have served to identify and validate many different approaches to countering infection with these highly pathogenic viruses. Nonetheless, predictive efficacy between each model does not appear to be equivalent as higher order animals seem to be more prognostic and therefore successful in the evaluation of medical countermeasures (MCM). Areas covered: This review comprehensively details the available small animal models of filovirus infection and discusses the benefits and shortcomings of each model with respect to the development of MCM. An up-to-date evaluation of mouse, hamster, guinea pig, and ferret models is provided. Expert opinion: The recent development of the domestic ferret model for ebolavirus offers a small animal model that faithfully reproduces most features of human disease without the need for viral adaptation or an immunocompromised host. That being said, choosing a small animal model to evaluate a particular MCM must consider potential confounders associated with each model. These confounding issues include incomplete host immune systems or mutations in the challenge virus that enables the disease.

10.
J Infect Dis ; 218(suppl_5): S565-S573, 2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29982718

RESUMO

Background: The 2013-2016 Ebola virus disease (EVD) epidemics in West Africa highlighted a need for effective therapeutics for treatment of the disease caused by filoviruses. Monoclonal antibodies (mAbs) are promising therapeutic candidates for prophylaxis or treatment of virus infections. Data about efficacy of human mAb monotherapy against filovirus infections in preclinical nonhuman primate models are limited. Methods: Previously, we described a large panel of human mAbs derived from the circulating memory B cells from Bundibugyo virus (BDBV) infection survivors that bind to the surface glycoprotein (GP) of the virus. We tested one of these neutralizing mAbs that recognized the glycan cap of the GP, designated mAb BDBV289, as monotherapy in rhesus macaques. Results: We found that recombinant mAb BDBV289-N could confer up to 100% protection to BDBV-infected rhesus macaques when treatment was initiated as late as 8 days after virus challenge. Protection was associated with survival and decreased viremia levels in the blood of treated animals. Conclusions: These findings define the efficacy of monotherapy of lethal BDBV infection with a glycan cap-specific mAb and identify a candidate mAb therapeutic molecule that could be included in antibody cocktails for prevention or treatment of ebolavirus infections.

11.
J Infect Dis ; 218(suppl_5): S582-S587, 2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29939296

RESUMO

A recombinant vesicular stomatitis virus (rVSV) expressing the Marburg virus (MARV) Musoke variant glycoprotein fully protects macaques against 2 MARV variants and Ravn virus as a preventive vaccine and MARV variant Musoke as a postexposure treatment. To evaluate postexposure efficacy against the most pathogenic MARV variant, Angola, we engineered rVSVs expressing homologous Angola glycoprotein. Macaques were challenged with high or low doses of variant Angola and treated 20-30 minutes after exposure. A total of 25% and 60%-75% of treated macaques survived the high-dose and low-dose challenges, respectively. The more rapid disease progression of variant Angola versus variant Musoke may account for the incomplete protection observed.

12.
J Infect Dis ; 218(suppl_5): S448-S452, 2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29955887

RESUMO

The domestic ferret was recently described as a uniformly lethal model for 3 species of Ebolavirus. More importantly, this new model utilizes nonadapted wild-type Ebolaviruses. Here, in a proof-of-concept study, we infected ferrets with different variants of the closely related Marburg and Ravn viruses using different doses and routes of exposure. Although ferrets produced a neutralizing humoral response to challenge, we did not observe disease or viremia in any animal. The lack of disease in ferrets underscores the notion that differential mechanisms to immunity among filoviruses exist and may provide a model to better understand how differences contribute to disease.

13.
Nat Rev Drug Discov ; 2018 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-29725132

RESUMO

This corrects the article DOI: 10.1038/nrd.2017.251.

14.
Sci Rep ; 8(1): 5939, 2018 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-29651117

RESUMO

Lassa fever, a hemorrhagic fever caused by Lassa virus (LASV), is endemic in West Africa. It is difficult to distinguish febrile illnesses that are common in West Africa from Lassa fever based solely on a patient's clinical presentation. The field performance of recombinant antigen-based Lassa fever immunoassays was compared to that of quantitative polymerase chain assays (qPCRs) using samples from subjects meeting the case definition of Lassa fever presenting to Kenema Government Hospital in Sierra Leone. The recombinant Lassa virus (ReLASV) enzyme-linked immunosorbant assay (ELISA) for detection of viral antigen in blood performed with 95% sensitivity and 97% specificity using a diagnostic standard that combined results of the immunoassays and qPCR. The ReLASV rapid diagnostic test (RDT), a lateral flow immunoassay based on paired monoclonal antibodies to the Josiah strain of LASV (lineage IV), performed with 90% sensitivity and 100% specificity. ReLASV immunoassays performed better than the most robust qPCR currently available, which had 82% sensitivity and 95% specificity. The performance characteristics of recombinant antigen-based Lassa virus immunoassays indicate that they can aid in the diagnosis of LASV Infection and inform the clinical management of Lassa fever patients.

15.
Nat Rev Drug Discov ; 17(6): 413-434, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29375139

RESUMO

The filoviruses - Ebola virus and Marburg virus - cause lethal haemorrhagic fever in humans and non-human primates (NHPs). Filoviruses present a global health threat both as naturally acquired diseases and as potential agents of bioterrorism. In the recent 2013-2016 outbreak of Ebola virus, the most promising therapies for post-exposure use with demonstrated efficacy in the gold-standard NHP models of filovirus disease were unable to show statistically significant protection in patients infected with Ebola virus. This Review briefly discusses these failures and what has been learned from these experiences, and summarizes the current status of post-exposure medical countermeasures in development, including antibodies, small interfering RNA and small molecules. We outline how our current knowledge could be applied to the identification of novel interventions and ways to use interventions more effectively.

16.
Front Immunol ; 8: 1372, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29123522

RESUMO

Existing models of Ebola virus disease (EVD) suggest antigen-presenting cells are initial targets of Zaire ebolavirus (ZEBOV). In vitro studies have shown that ZEBOV infection of monocytes and macrophages results in the production of inflammatory mediators, which may cause lymphocyte apoptosis. However, these findings have not been corroborated by in vivo studies. In this study, we report the first longitudinal analysis of transcriptional changes in purified monocytes, T-cells, and B-cells isolated from cynomolgus macaques following infection with ZEBOV-Makona. Our data reveal monocytes as one of the major immune cell subsets that supports ZEBOV replication in vivo. In addition, we report a marked increase in the transcription of genes involved in inflammation, coagulation, and vascular disease within monocytes, suggesting that monocytes contribute to EVD manifestations. Further, genes important for antigen presentation and regulation of immunity were downregulated, potentially subverting development of adaptive immunity. In contrast, lymphocytes, which do not support ZEBOV replication, showed transcriptional changes limited to a small number of interferon-stimulated genes (ISGs) and a failure to upregulate genes associated with an antiviral effector immune response. Collectively, these data suggest that ZEBOV-infected monocytes play a significant role in ZEBOV-Makona pathogenesis and strategies to suppress virus replication or modify innate responses to infection in these cells should be a priority for therapeutic intervention.

17.
J Clin Invest ; 127(12): 4437-4448, 2017 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29106386

RESUMO

Ebolaviruses and marburgviruses belong to the family Filoviridae and cause high lethality in infected patients. There are currently no licensed filovirus vaccines or antiviral therapies. The development of broad-spectrum therapies against members of the Marburgvirus genus, including Marburg virus (MARV) and Ravn virus (RAVV), is difficult because of substantial sequence variability. RNAi therapeutics offer a potential solution, as identification of conserved target nucleotide sequences may confer activity across marburgvirus variants. Here, we assessed the therapeutic efficacy of lipid nanoparticle (LNP) delivery of a single nucleoprotein-targeting (NP-targeting) siRNA in nonhuman primates at advanced stages of MARV or RAVV disease to mimic cases in which patients begin treatment for fulminant disease. Sixteen rhesus monkeys were lethally infected with MARV or RAVV and treated with NP siRNA-LNP, with MARV-infected animals beginning treatment four or five days after infection and RAVV-infected animals starting treatment three or six days after infection. While all untreated animals succumbed to disease, NP siRNA-LNP treatment conferred 100% survival of RAVV-infected macaques, even when treatment began just 1 day prior to the death of the control animals. In MARV-infected animals, day-4 treatment initiation resulted in 100% survival, and day-5 treatment resulted in 50% survival. These results identify a single siRNA therapeutic that provides broad-spectrum protection against both MARV and RAVV.

18.
Nat Med ; 23(10): 1146-1149, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28869611

RESUMO

There are no approved treatments for Lassa fever, which is endemic to the same regions of West Africa that were recently devastated by Ebola. Here we show that a combination of human monoclonal antibodies that cross-react with the glycoproteins of all four clades of Lassa virus is able to rescue 100% of cynomolgus macaques when treatment is initiated at advanced stages of disease, including up to 8 d after challenge.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/uso terapêutico , Febre Lassa/prevenção & controle , Animais , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , Evasão da Resposta Imune/genética , Imuno-Histoquímica , Vírus Lassa/genética , Macaca fascicularis , RNA Viral/sangue , Distribuição Aleatória , Taxa de Sobrevida , Carga Viral
19.
Sci Rep ; 7(1): 9730, 2017 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-28852031

RESUMO

Zaire Ebolavirus (ZEBOV) continues to pose a significant threat to human health as highlighted by the recent epidemic that originated in West Africa and the ongoing outbreak in the Democratic Republic of the Congo. Although the ZEBOV variant responsible for this epidemic (Makona) shares significant genetic similarity with previously identified variants (Kikwit and Mayinga), recent reports suggest slower disease progression in nonhuman primates. However, the pathogenesis caused by the new variant is not fully understood. We present the first comprehensive approach in understanding ZEBOV-Makona pathogenesis in cynomolgus macaques by measuring changes in immune cell frequencies, plasma levels of immune mediators, and differentially expressed genes (DEGs) within whole blood (WB) and peripheral blood mononuclear cells (PBMC). Our combined approach revealed a link between: 1) increased interferon-stimulated gene expression, IFNα levels, and activated plasmacytoid dendritic cells; 2) higher proinflammatory gene expression, cytokine and chemokine levels, and non-classical monocytes; 3) gene signature of leukocyte activation and increased granulocytes; and 4) decreased expression of lymphocyte related genes and lymphopenia. In addition, our data strongly indicate delayed disease progression as well as limited overlap (~30%) in host transcriptome changes following ZEBOV-Makona infection compared to ZEBOV-Kikwit. These observations provide novel insight into the molecular mechanisms of ZEBOV-Makona pathogenesis.

20.
Methods Mol Biol ; 1628: 353-362, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28573634

RESUMO

Immunologic assays such as ELISA allow detection of either virus antigens or the host's immune response to antigens associated with prior infections and offer a powerful means to approach understanding the epidemiology and epizootiology of these agents. However, the success of these assays is highly dependent on the production of high-quality materials both to establish the assays (i.e., antigen target for antibody) and to serve as controls for establishing assay parameters and sensitivity. Here we describe methods for preparing ebolavirus antigens suitable for use as either reagents or controls in a variety of ELISA formats. Considering work with filoviruses is typically restricted to maximum containment laboratories; thus, we also provide methods for inactivating and safety testing of these antigens for safe use in properly established field laboratories.


Assuntos
Antígenos Virais/imunologia , Ebolavirus/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Doença pelo Vírus Ebola/imunologia , Anticorpos Antivirais/imunologia , Reações Cruzadas/imunologia , Ebolavirus/isolamento & purificação , Doença pelo Vírus Ebola/virologia , Humanos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA