Publications

a small nonhuman primate model for filovirus-induced disease.	ebolavirus and marburgvirus are members of the filovirus family and induce a fatal hemorrhagic disease in humans and nonhuman primates with 90% case fatality. to develop a small nonhuman primate model for filovirus disease, common marmosets (callithrix jacchus) were intramuscularly inoculated with wild type marburgvirus musoke or ebolavirus zaire. the infection resulted in a systemic fatal disease with clinical and morphological features closely resembling human infection. animals experienced we ...	2011	21959017
real-time monitoring of cardiovascular function in rhesus macaques infected with zaire ebolavirus.	nine rhesus macaques were implanted with multisensor telemetry devices and internal jugular vein catheters before being infected with zaire ebolavirus. all animals developed viremia, fever, a hemorrhagic rash, and typical changes of ebola hemorrhagic fever in clinical laboratory tests. three macaques unexpectedly survived this usually lethal disease, making it possible to compare physiological parameters in lethally challenged animals and survivors. after the onset of fever, lethal illness was c ...	2011	21987736
vp24 is a molecular determinant of ebola virus virulence in guinea pigs.	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 rep ...	2011	21987737
impact of systemic or mucosal immunity to adenovirus on ad-based ebola virus vaccine efficacy in guinea pigs.	approximately 35% of the north american population and an estimated 90% of the sub-saharan african population have antibodies against adenovirus serotype 5 (adhu5) that are capable of neutralizing adhu5-based vaccines. in mice, intranasal delivery of adhu5 expressing the zaire ebolavirus glycoprotein human adenovirus serotype 5 (ad) containing the genes for the zaire ebolavirus glycoprotein (zgp) under the expressional control of a cytomegalovirus immediate early promoter (cmv)) can bypass syste ...	2011	21987739
therapeutics of ebola hemorrhagic fever: whole-genome transcriptional analysis of successful disease mitigation.	the mechanisms of ebola (ebov) pathogenesis are only partially understood, but the dysregulation of normal host immune responses (including destruction of lymphocytes, increases in circulating cytokine levels, and development of coagulation abnormalities) is thought to play a major role. accumulating evidence suggests that much of the observed pathology is not the direct result of virus-induced structural damage but rather is due to the release of soluble immune mediators from ebov-infected cell ...	2011	21987740
vesicular stomatitis virus-based ebola vaccines with improved cross-protective efficacy.	for ebola virus (ebov), 4 different species are known: zaire, sudan, côte d'ivoire, and reston ebolavirus. the newly discovered bundibugyo ebolavirus has been proposed as a 5th species. so far, no cross-neutralization among ebov species has been described, aggravating progress toward cross-species protective vaccines. with the use of recombinant vesicular stomatitis virus (rvsv)-based vaccines, guinea pigs could be protected against zaire ebolavirus (zebov) infection only when immunized with a v ...	2011	21987743
Recombinant vesicular stomatitis virus-based vaccines against Ebola and Marburg virus infections.	The filoviruses, Marburg virus and Ebola virus, cause severe hemorrhagic fever with a high mortality rate in humans and nonhuman primates. Among the most-promising filovirus vaccines under development is a system based on recombinant vesicular stomatitis virus (rVSV) that expresses a single filovirus glycoprotein (GP) in place of the VSV glycoprotein (G). Importantly, a single injection of blended rVSV-based filovirus vaccines was shown to completely protect nonhuman primates against Marburg vir ...	2011	21987744
single immunization with a monovalent vesicular stomatitis virus-based vaccine protects nonhuman primates against heterologous challenge with bundibugyo ebolavirus.	the recombinant vesicular stomatitis virus (rvsv) vector-based monovalent vaccine platform expressing a filovirus glycoprotein has been demonstrated to provide protection from lethal challenge with ebola (ebov) and marburg (marv) viruses both prophylactically and after exposure. this platform provides protection between heterologous strains within a species; however, protection from lethal challenge between species has been largely unsuccessful. to determine whether the rvsv-ebov vaccines have t ...	2011	21987745
protective efficacy of a bivalent recombinant vesicular stomatitis virus vaccine in the syrian hamster model of lethal ebola virus infection.	outbreaks of filoviral hemorrhagic fever occur sporadically and unpredictably across wide regions in central africa and overlap with the occurrence of other infectious diseases of public health importance.	2011	21987746
reston ebolavirus in humans and animals in the philippines: a review.	the 2008 reston ebolavirus infection event in domestic pigs has triggered continuing epidemiologic investigations among philippine health and veterinary agencies in collaboration with international filovirus experts. prior to this, there were only 3 known and documented reston ebolavirus outbreaks in nonhuman primates in the world, all traced back to a single geographic source in the philippines in a monkey breeding/export facility. the first one in 1989 was the first-ever ebola virus that emerg ...	2011	21987747
filovirus outbreak detection and surveillance: lessons from bundibugyo.	the first outbreak of ebola hemorrhagic fever (ehf) due to bundibugyo ebolavirus occurred in uganda from august to december 2007. during outbreak response and assessment, we identified 131 ehf cases (44 suspect, 31 probable, and 56 confirmed). consistent with previous large filovirus outbreaks, a long temporal lag (approximately 3 months) occurred between initial ehf cases and the subsequent identification of ebola virus and outbreak response, which allowed for prolonged person-to-person transmi ...	2011	21987748
risk factors for zaire ebolavirus--specific igg in rural gabonese populations.	in gabon, several ebolavirus outbreaks have occurred exclusively in the northeastern region. we conducted a large serosurvey to identify areas and populations at risk and potential demographic, clinical, and behavioral risk factors.	2011	21987749
Emergence of divergent Zaire ebola virus strains in Democratic Republic of the Congo in 2007 and 2008.	Zaire ebolavirus was responsible for 2 outbreaks in Democratic Republic of the Congo (DRC), in 1976 and 1995. The virus reemerged in DRC 12 years later, causing 2 successive outbreaks in the Luebo region, Kasai Occidental province, in 2007 and 2008.	2011	21987750
management of accidental exposure to ebola virus in the biosafety level 4 laboratory, hamburg, germany.	a needlestick injury occurred during an animal experiment in the biosafety level 4 laboratory in hamburg, germany, in march 2009. the syringe contained zaire ebolavirus (zebov) mixed with freund's adjuvant. neither an approved treatment nor a postexposure prophylaxis (pep) exists for ebola hemorrhagic fever. following a risk-benefit assessment, it was recommended the exposed person take an experimental vaccine that had shown pep efficacy in zebov-infected nonhuman primates (nhps) [12]. the vacci ...	2011	21987751
ebola reston virus infection of pigs: clinical significance and transmission potential.	in 2008, reston ebolavirus (rebov) was isolated from pigs during a disease investigation in the philippines. porcine reproductive and respiratory syndrome virus (prrsv) and porcine circovirus type 2 (pcv-2) infections were also confirmed in affected herds and the contribution of rebov to the disease outbreak remains uncertain. we have conducted experimental challenge studies in 5-week-old pigs, with exposure of animals to 10(6) tcid(50) of a 2008 swine isolate of rebov via either the oronasal or ...	2011	21987755
characterization of filovirus protein-protein interactions in mammalian cells using bimolecular complementation.	the virion protein 40 (vp40) and nucleoprotein (np) of ebola (ebov) and marburg viruses (marv) play key roles during virion assembly and egress. the ability to detect interactions between vp40-vp40, vp40-np, and np-np and follow these complexes as they traffic through mammalian cells would enhance our understanding of the molecular events leading to filovirus assembly and budding, and provide new insights into filovirus replication and pathogenesis. here, we successfully employed a bimolecular c ...	2011	21987757
impact of ebola mucin-like domain on antiglycoprotein antibody responses induced by ebola virus-like particles.	ebola virus (ebov) glycoprotein (gp), responsible for mediating host-cell attachment and membrane fusion, contains a heavily glycosylated mucin-like domain hypothesized to shield gp from neutralizing antibodies. to test whether the mucin-like domain inhibits the production and function of anti-gp antibodies, we vaccinated mice with ebola virus-like particles (vlps) that express vesicular stomatitis virus g, wild-type ebov gp (ebgp), ebov gp without its mucin-like domain (δmucgp), or ebov gp with ...	2011	21987758
unconventional secretion of ebola virus matrix protein vp40.	the ebola virus matrix protein vp40 plays an essential role in virus assembly and budding. in this study we reveal that transient vp40 expression results in the release into the culture medium of substantial amounts of soluble monomeric vp40 in addition to the release of virus-like particles containing an oligomeric form of this protein as previously described. we show that vp40 secretion is endoplasmic reticulum/golgi-independent and is not associated with cell death. soluble vp40 was observed ...	2011	21987759
Comparative analysis of Ebola virus glycoprotein interactions with human and bat cells.	Infection with Ebola virus (EBOV) causes hemorrhagic fever in humans with high case-fatality rates. The EBOV-glycoprotein (EBOV-GP) facilitates viral entry and promotes viral release from human cells. African fruit bats are believed not to develop disease upon EBOV infection and have been proposed as a natural reservoir of EBOV. We compared EBOV-GP interactions with human cells and cells from African fruit bats. We found that susceptibility to EBOV-GP-dependent infection was not limited to bat c ...	2011	21987760
the ebola virus glycoprotein and hiv-1 vpu employ different strategies to counteract the antiviral factor tetherin.	the antiviral protein tetherin/bst2/cd317/hm1.24 restricts cellular egress of human immunodeficiency virus (hiv) and of particles mimicking the ebola virus (ebov), a hemorrhagic fever virus. the hiv-1 viral protein u (vpu) and the ebov-glycoprotein (ebov-gp) both inhibit tetherin. here, we compared tetherin counteraction by ebov-gp and vpu. we found that ebov-gp but not vpu counteracted tetherin from different primate species, indicating that ebov-gp and vpu target tetherin differentially. tethe ...	2011	21987761
The importance of the NP: VP35 ratio in Ebola virus nucleocapsid formation.	Ebola virus VP35 is a cofactor of the viral RNA polymerase complex and, together with NP and VP24, is an essential component for nucleocapsid formation. In the present study, we examined the interactions between VP35 and NP and found that VP35 interacts with helical NP-RNA complexes through the C-terminus of NP. We also found that coexpression of excess VP35 with NP reduced the yields of NP-RNA complexes purified by CsCl gradient ultracentrifugation and inhibited the formation of the NP-induced ...	2011	21987764
Conserved proline-rich region of Ebola virus matrix protein VP40 is essential for plasma membrane targeting and virus-like particle release.	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, ...	2011	21987765
Knockdown of Ebola virus VP24 impairs viral nucleocapsid assembly and prevents virus replication.	The structural protein VP24 of Ebola virus (EBOV) is a determinant of virulence in rodent models and possesses an interferon antagonist function. In this study, we investigate the role of VP24 in EBOV replication using RNA interference by small interfering RNA to knock down the expression of this protein in virus-infected cells. We reveal that VP24 is required for assembly of viral nucleocapsids and that silencing of VP24 expression prevents the release of EBOV.	2011	21987766
sgp serves as a structural protein in ebola virus infection.	sgp, which is perceived as nonstructural, secretory glycoprotein, shares 295 amino acids at its n-terminal with gp(1,2), which include the specific residue necessary to interact with gp(2). in the present study, we tested whether the sgp protein of zaire ebolavirus (zebov) could substitute for gp(1) and form a complex with gp(2), thus serving as a structural protein.	2011	21987767
the ebola virus vp24 protein prevents hnrnp c1/c2 binding to karyopherin α1 and partially alters its nuclear import.	the ebola virus (ebov) protein vp24 inhibits type i and ii interferon (ifn) signaling by binding to npi-1 subfamily karyopherin α (kpna) nuclear import proteins, preventing their interaction with tyrosine-phosphorylated stat1 (phospho-stat1). this inhibits phospho-stat1 nuclear import. a biochemical screen now identifies heterogeneous nuclear ribonuclear protein complex c1/c2 (hnrnp c1/c2) nuclear import as an additional target of vp24. co-immunoprecipitation studies demonstrate that hnrnp c1/c2 ...	2011	21987768
drbp76 associates with ebola virus vp35 and suppresses viral polymerase function.	the zaire ebola virus (ebov) protein vp35 is multifunctional; it inhibits ifn-α/β production and functions as a cofactor of the viral rna polymerase. mass spectrometry identified the double stranded rna binding protein 76 (drbp76/nfar-1/nf90) as a cellular factor that associates with the vp35 c-terminal interferon inhibitory domain (iid). drbp76 is described to regulate host cell protein synthesis and play an important role in host defense. the vp35-iid-drbp76 interaction required the addition o ...	2011	21987769
Contribution of Sec61a to the life cycle of Ebola virus.	Similar to other viruses, the viral proteins of Ebola virus (EBOV) interact with a variety of host proteins for its replication. Of the 7 structural proteins encoded in the EBOV genome, VP24 is the smallest and is multifunctional.	2011	21987770
Role of VP30 phosphorylation in the Ebola virus replication cycle.	Ebola virus (EBOV) transcription is dependent on the phosphoprotein VP30, a component of the viral nucleocapsid. VP30 is phosphorylated at 2 serine residue clusters located at the N-terminal part of the protein. In this report, we have investigated the role of VP30 phosphorylation in EBOV replication using a reverse genetics approach. In effect, recombinant EBOVs with the VP30 serine clusters substituted either by nonphosphorylatable alanines or phosphorylation-mimicking aspartates were generate ...	2011	21987772
genomic rna editing and its impact on ebola virus adaptation during serial passages in cell culture and infection of guinea pigs.	synthesis of the structural, surface glycoprotein (gp) of ebola virus (ebov) is dependent on transcriptional rna editing phenomenon. editing results in the insertion of an extra adenosine by viral polymerase at the editing site (7 consecutive template uridines) during transcription of gp gene of the wild-type virus (ebov/7u). in this study, we demonstrate that passage of ebov/7u in vero e6 cells results in the appearance and rapid accumulation of a variant (ebov/8u) containing an additional urid ...	2011	21987773
The Ebola virus soluble glycoprotein (sGP) does not affect lymphocyte apoptosis and adhesion to activated endothelium.	Ebola virus infection is associated with the release of a soluble glycoprotein (sGP) from infected cells. The sGP has been proposed to modulate Ebola virus pathogenesis in primates but little is known about the role of this protein during infection and disease manifestation. So far sGP has been shown to revert the effect of tumor necrosis factor a (TNF-a) on endothelial permeability, indicating that the function of sGP might be antiinflammatory. Since bystander apoptosis of lymphocytes has been ...	2011	21987774
the ebolavirus vp24 protein blocks phosphorylation of p38 mitogen-activated protein kinase.	type i interferon (ifn) signaling is mediated through several signaling pathways, including the janus kinase and signal transducer and activator (jak-stat) and p38 mitogen-activated protein (map) kinase pathways. the vp24 protein of ebolavirus is an ifn antagonist, blocking type i ifn signaling through the jak-stat pathway. here, we show that, in 293 cells, vp24 also interferes with the p38 map kinase pathway by blocking ifn-β-stimulated phosphorylation of p38-α. similar inhibition was not obser ...	2011	21987775
Ebola virus enters host cells by macropinocytosis and clathrin-mediated endocytosis.	Virus entry into host cells is the first step of infection and a crucial determinant of pathogenicity. Here we show that Ebola virus-like particles (EBOV-VLPs) composed of the glycoprotein GP(1,2) and the matrix protein VP40 use macropinocytosis and clathrin-mediated endocytosis to enter cells. EBOV-VLPs applied to host cells induced actin-driven ruffling and enhanced FITC-dextran uptake, which indicated macropinocytosis as the main entry mechanism. This was further supported by inhibition of en ...	2011	21987776
assessment of rodents as animal models for reston ebolavirus.	the emergence of reston ebolavirus (rebov) in domestic swine in the philippines has caused a renewed interest in rebov pathogenicity. here, the use of different rodent species as animal disease models for rebov was investigated. balb/c and stat1(-)(/-) mice, hartley guinea pigs, and syrian hamsters were inoculated intraperitoneally with rebov strain pennsylvania or reston08-a. although virus replication occurred in guinea pigs, hamsters, and stat1(-/-) mice, progression to disease was only obser ...	2011	21987777
Ebola virus failure to stimulate plasmacytoid dendritic cell interferon responses correlates with impaired cellular entry.	We examined the ability of the Ebola virus to elicit an antiviral response from plasmacytoid dendritic cells (pDCs). Exposure of pDCs to Ebola virus did not result in significantly higher levels of interferon-a production than the levels in mock-infected cells. After inoculation with Ebola virus under the same conditions, conventional dendritic cells expressed viral proteins whereas pDCs did not, suggesting that the latter cells were not infected. Assessment of the entry of Ebola virus-like part ...	2011	21987778
filovirus infection of stat-1 knockout mice.	we evaluated the susceptibility to ebola and marburg virus infection of mice that cannot respond to interferon (ifn)-α/β and ifn-γ because of deletion of the stat-1 gene. a mouse-adapted zaire ebolavirus (zebov) caused rapidly lethal disease; wild-type zebov and sudan ebolavirus and 4 different marburg virus strains produced severe, but more slowly progressive illness; and reston ebolavirus caused mild disease that was late in onset. the virulence of each agent was mirrored by the pace and sever ...	2011	21987780
Host response dynamics following lethal infection of rhesus macaques with Zaire ebolavirus.	To gain further insight into the interdependent pathogenic processes in Ebola hemorrhagic fever (EHF), we have examined the dynamics of host responses in individual rhesus macaques infected with Zaire ebolavirus over the entire disease course. Examination of coagulation parameters revealed that decreased coagulation inhibitor activity triggered severe coagulopathy as indicated by prolonged coagulation times and decreased fibrinogen levels. This has been proposed as one of the significant mechani ...	2011	21987781
Filoviral immune evasion mechanisms.	The Filoviridae family of viruses, which includes the genera Ebolavirus (EBOV) and Marburgvirus (MARV), causes severe and often times lethal hemorrhagic fever in humans. Filoviral infections are associated with ineffective innate antiviral responses as a result of virally encoded immune antagonists, which render the host incapable of mounting effective innate or adaptive immune responses. The Type I interferon (IFN) response is critical for establishing an antiviral state in the host cell and su ...	2011	21994800
Ebola virion attachment and entry into human macrophages profoundly effects early cellular gene expression.	Zaire ebolavirus (ZEBOV) infections are associated with high lethality in primates. ZEBOV primarily targets mononuclear phagocytes, which are activated upon infection and secrete mediators believed to trigger initial stages of pathogenesis. The characterization of the responses of target cells to ZEBOV infection may therefore not only further understanding of pathogenesis but also suggest possible points of therapeutic intervention. Gene expression profiles of primary human macrophages exposed t ...	2011	22028943
Discovery of an ebolavirus-like filovirus in europe.	Filoviruses, amongst the most lethal of primate pathogens, have only been reported as natural infections in sub-Saharan Africa and the Philippines. Infections of bats with the ebolaviruses and marburgviruses do not appear to be associated with disease. Here we report identification in dead insectivorous bats of a genetically distinct filovirus, provisionally named Lloviu virus, after the site of detection, Cueva del Lloviu, in Spain.	2011	22039362
evolutionary maintenance of filovirus-like genes in bat genomes.	little is known of the biological significance and evolutionary maintenance of integrated non-retroviral rna virus genes in eukaryotic host genomes. here, we isolated novel filovirus-like genes from bat genomes and tested for evolutionary maintenance. we also estimated the age of filovirus vp35-like gene integrations and tested the phylogenetic hypotheses that there is a eutherian mammal clade and a marsupial/ebolavirus/marburgvirus dichotomy for filoviruses.	2011	22093762
A shared structural solution for neutralizing ebolaviruses.	Sudan virus (genus Ebolavirus) is lethal, yet no monoclonal antibody is known to neutralize it. We here describe antibody 16F6 that neutralizes Sudan virus and present its structure bound to the trimeric viral glycoprotein. Unexpectedly, the 16F6 epitope overlaps that of KZ52, the only other antibody against the GP(1,2) core to be visualized to date. Furthermore, both antibodies against this crucial epitope bridging GP1-GP2 neutralize at a post-internalization step-probably fusion.	2011	22101933
Ebola virus glycoprotein needs an additional trigger, beyond proteolytic priming for membrane fusion.	Ebolavirus belongs to the family filoviridae and causes severe hemorrhagic fever in humans with 50-90% lethality. Detailed understanding of how the viruses attach to and enter new host cells is critical to development of medical interventions. The virus displays a trimeric glycoprotein (GP(1,2)) on its surface that is solely responsible for membrane attachment, virus internalization and fusion. GP(1,2) is expressed as a single peptide and is cleaved by furin in the host cells to yield two disulp ...	2011	22102923
Ebolavirus: a brief review of novel therapeutic targets.		2012	22191439
serology and cytokine profiles in patients infected with the newly discovered bundibugyo ebolavirus.	a new species of ebolavirus, bundibugyo ebolavirus, was discovered in an outbreak in western uganda in november 2007. to study the correlation between fatal infection and immune response in bundibugyo ebolavirus infection, viral antigen, antibodies, and 17 soluble factors important for innate immunity were examined in 44 patient samples. using luminex assays, we found that fatal infection was associated with high levels of viral antigen, low levels of pro-inflammatory cytokines, such as il-1α, i ...	2011	22197674
filoviruses require endosomal cysteine proteases for entry but exhibit distinct protease preferences.	filoviruses are enveloped viruses that cause sporadic outbreaks of severe hemorrhagic fever (6, 8, 9, 16). previous studies revealed that endosomal cysteine proteases are host factors for ebolavirus zaire (7, 35). in this report, we show that infection mediated by glycoproteins from other phylogenetically-diverse filoviruses are also dependent on these proteases and provide additional evidence indicating they cleave gp1 and expose the binding domain for the critical host factor niemann-pick c1. ...	2012	22238307
induction of ebolavirus cross-species immunity using retrovirus-like particles bearing the ebola virus glycoprotein lacking the mucin-like domain.	abstract: background: the genus ebolavirus includes five distinct viruses. four of these viruses cause hemorrhagic fever in humans. currently there are no licensed vaccines for any of them; however, several vaccines are under development. ebola virus envelope glycoprotein (gp1,2) is highly immunogenic, but antibodies frequently arise against its least conserved mucin-like domain (mld). we hypothesized that immunization with mld-deleted gp1,2 (gpdeltamld) would induce cross-species immunity by m ...	2012	22273269