Inhibition of Marburg Virus Budding by Nonneutralizing Antibodies to the Envelope Glycoprotein

Kajihara, Masahiro; Marzi, Andrea; Nakayama, Eri; Noda, Takeshi; Kuroda, Makoto; Manzoor, Rashid; Matsuno, Keita; Feldmann, Heinz; Yoshida, Reiko; Kawaoka, Yoshihiro; Takada, Ayato

doi:10.1128/jvi.01896-12

Cited by 57 publications

(69 citation statements)

References 51 publications

(63 reference statements)

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“…Antibodies may protect from EVD by directly neutralizing the virus, but nonneutralizing antibodies can also be protective (54). One potential mechanism of protection by nonneutralizing antibodies may rely on the inhibition of filovirus particle release from cells (55). NK cell-mediated antibody-dependent cellular cytolysis (ADCC), complement-mediated cell lysis, and macrophage-mediated antibody-dependent cellular phagocytosis (ADCP) might also contribute to protection by antibodies.…”

Section: Discussionmentioning

confidence: 99%

Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

Schweneker

Laimbacher

Zimmer³

et al. 2017

J Virol

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There are currently no approved therapeutics or vaccines to treat or protect against the severe hemorrhagic fever and death caused by Ebola virus (EBOV). Ebola virus-like particles (EBOV VLPs) consisting of the matrix protein VP40, the glycoprotein (GP), and the nucleoprotein (NP) are highly immunogenic and protective in nonhuman primates against Ebola virus disease (EVD). We have constructed a modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) recombinant coexpressing VP40 and GP of EBOV Mayinga and the NP of Taï Forest virus (TAFV) (MVA-BN-EBOV-VLP) to launch noninfectious EBOV VLPs as a second vaccine modality in the MVA-BN-EBOV-VLP-vaccinated organism. Human cells infected with either MVA-BN-EBOV-VLP or MVA-BN-EBOV-GP showed comparable GP expression levels and transport of complex N-glycosylated GP to the cell surface. Human cells infected with MVA-BN-EBOV-VLP produced large amounts of EBOV VLPs that were decorated with GP spikes but excluded the poxviral membrane protein B5, thus resembling authentic EBOV particles. The heterologous TAFV NP enhanced EBOV VP40-driven VLP formation with efficiency similar to that of the homologous EBOV NP in a transientexpression assay, and both NPs were incorporated into EBOV VLPs. EBOV GP-specific CD8 T cell responses were comparable between MVA-BN-EBOV-VLP-and MVA-BN-EBOV-GP-immunized mice. The levels of EBOV GP-specific neutralizing and binding antibodies, as well as GP-specific IgG1/IgG2a ratios induced by the two constructs, in mice were also similar, raising the question whether the quality rather than the quantity of the GP-specific antibody response might be altered by an EBOV VLPgenerating MVA recombinant.IMPORTANCE The recent outbreak of Ebola virus (EBOV), claiming more than 11,000 lives, has underscored the need to advance the development of safe and effective filovirus vaccines. Virus-like particles (VLPs), as well as recombinant viral vectors, have proved to be promising vaccine candidates. Modified vaccinia virus Ankara-Bavarian Nordic (MVA-BN) is a safe and immunogenic vaccine vector with a large capacity to accommodate multiple foreign genes. In this study, we combined the advantages of VLPs and the MVA platform by generating a recombinant MVA-BN-EBOV-VLP that would produce noninfectious EBOV VLPs in the vaccinated individual. Our results show that human cells infected with MVA-BN-EBOV-VLP indeed formed and released EBOV VLPs, thus producing a highly authentic immunogen. MVA-BN-EBOV-VLP efficiently induced EBOV-specific humoral and cellular immune responses in vaccinated mice. These results are the basis for future advancements, e.g., by including antigens from various filoviral species to develop multivalent VLP-producing MVA-based filovirus vaccines.

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Section: Discussionmentioning

confidence: 99%

Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

Schweneker

Laimbacher

Zimmer³

et al. 2017

J Virol

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“…None of the MB-003 mAbs are neutralizing in the absence of complement (29), but both ZMAb and MB-003 mixtures are protective (22,27). Nonneutralizing antibodies could confer in vivo protection by preventing budding of nascent virions, as has been proposed for Marburg virus (37), or by conferring antibodydependent cellular cytotoxicity or another immune mechanism. For EBOV, antibodies against the mucin-like domains of the glycoprotein (GP) are generally nonneutralizing because these domains, as well as any antibodies bound to them, are stripped from the viral surface by host cathepsins in the endosome, leaving behind an antibody-free, functional receptor-binding core of GP (16,38).…”

mentioning

confidence: 98%

Structures of protective antibodies reveal sites of vulnerability on Ebola virus

Murin¹,

Fusco²,

Bornholdt³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

172

251

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Ebola virus (EBOV) and related filoviruses cause severe hemorrhagic fever, with up to 90% lethality, and no treatments are approved for human use. Multiple recent outbreaks of EBOV and the likelihood of future human exposure highlight the need for pre-and postexposure treatments. Monoclonal antibody (mAb) cocktails are particularly attractive candidates due to their proven postexposure efficacy in nonhuman primate models of EBOV infection. Two candidate cocktails, MB-003 and ZMAb, have been extensively evaluated in both in vitro and in vivo studies. Recently, these two therapeutics have been combined into a new cocktail named ZMapp, which showed increased efficacy and has been given compassionately to some human patients. Epitope information and mechanism of action are currently unknown for most of the component mAbs. Here we provide single-particle EM reconstructions of every mAb in the ZMapp cocktail, as well as additional antibodies from MB-003 and ZMAb. Our results illuminate key and recurring sites of vulnerability on the EBOV glycoprotein and provide a structural rationale for the efficacy of ZMapp. Interestingly, two of its components recognize overlapping epitopes and compete with each other for binding. Going forward, this work now provides a basis for strategic selection of next-generation antibody cocktails against Ebola and related viruses and a model for predicting the impact of ZMapp on potential escape mutations in ongoing or future Ebola outbreaks.

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“…In the absence of reverse genetics systems and/or biosafety level 4 (BSL-4) facilities required for work with filoviruses, researchers use various surrogate systems for characterization of filovirus-specific MAbs or investigation of various steps of filovirus life cycle involving GP. These systems include chimeric vesicular stomatitis Indiana viruses (VSV) with the G protein replaced with filovirus GP (19)(20)(21) and pseudotyped gammaretroviruses (22,23) and lentiviruses (24)(25)(26), which have their respective envelope proteins replaced with a filovirus GP provided in trans. It is generally assumed that these surrogate systems can be used to accurately characterize neutralizing properties of filovirus polyclonal or monoclonal antibodies.…”

mentioning

confidence: 99%

Chimeric Filoviruses for Identification and Characterization of Monoclonal Antibodies

Ilinykh

Shen

Flyak

et al. 2016

J Virol

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Recent experiments suggest that some glycoprotein (GP)-specific monoclonal antibodies (MAbs) can protect experimental animals against the filovirus Ebola virus (EBOV). There is a need for isolation of MAbs capable of neutralizing multiple filoviruses.Antibody neutralization assays for filoviruses frequently use surrogate systems such as the rhabdovirus vesicular stomatitis Indiana virus (VSV), lentiviruses or gammaretroviruses with their envelope proteins replaced with EBOV GP or pseudotyped with EBOV GP. It is optimal for both screening and in-depth characterization of newly identified neutralizing MAbs to generate recombinant filoviruses that express a reporter fluorescent protein in order to more easily monitor and quantify the infection. Our study showed that unlike neutralization-sensitive chimeric VSV, authentic filoviruses are highly resistant to neutralization by MAbs. We used reverse genetics techniques to replace EBOV GP with its counterpart from the heterologous filoviruses Bundibugyo virus (BDBV), Sudan virus, and even Marburg virus and Lloviu virus, which belong to the heterologous genera in the filovirus family. This work resulted in generation of multiple chimeric filoviruses, demonstrating the ability of filoviruses to tolerate swapping of the envelope protein. The sensitivity of chimeric filoviruses to neutralizing MAbs was similar to that of authentic biologically derived filoviruses with the same GP. Moreover, disabling the expression of the secreted GP (sGP) resulted in an increased susceptibility of an engineered virus to the BDBV52 MAb isolated from a BDBV survivor, suggesting a role for sGP in evasion of antibody neutralization in the context of a human filovirus infection. IMPORTANCEThe study demonstrated that chimeric rhabdoviruses in which G protein is replaced with filovirus GP, widely used as surrogate targets for characterization of filovirus neutralizing antibodies, do not accurately predict the ability of antibodies to neutralize authentic filoviruses, which appeared to be resistant to neutralization. However, a recombinant EBOV expressing a fluorescent protein tolerated swapping of GP with counterparts from heterologous filoviruses, allowing high-throughput screening of B cell lines to isolate MAbs of any filovirus specificity. Human MAb BDBV52, which was isolated from a survivor of BDBV infection, was capable of partially neutralizing a chimeric EBOV carrying BDBV GP in which expression of sGP was disabled. In contrast, the parental virus expressing sGP was resistant to the MAb. Thus, the ability of filoviruses to tolerate swapping of GP can be used for identification of neutralizing MAbs specific to any filovirus and for the characterization of MAb specificity and mechanism of action.T he family Filoviridae is composed of the genus Ebolavirus, which includes Ebola (EBOV), Sudan (SUDV), Taï Forest (TAFV), Reston (RESTV), and Bundibugyo (BDBV) viruses, the genus Marburgvirus, which includes Marburg (MARV) and Ravn (RAVV) viruses, and the putative genus Cuevavirus, which i...

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Inhibition of Marburg Virus Budding by Nonneutralizing Antibodies to the Envelope Glycoprotein

Cited by 57 publications

References 51 publications

Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

Recombinant Modified Vaccinia Virus Ankara Generating Ebola Virus-Like Particles

Structures of protective antibodies reveal sites of vulnerability on Ebola virus

Chimeric Filoviruses for Identification and Characterization of Monoclonal Antibodies

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