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PLoS Pathogens Sep 2023The Pneumoviridae family of viruses includes human metapneumovirus (HMPV) and respiratory syncytial virus (RSV). The closely related Paramyxoviridae family includes...
Structure-based design of a single-chain triple-disulfide-stabilized fusion-glycoprotein trimer that elicits high-titer neutralizing responses against human metapneumovirus.
The Pneumoviridae family of viruses includes human metapneumovirus (HMPV) and respiratory syncytial virus (RSV). The closely related Paramyxoviridae family includes parainfluenza viruses (PIVs). These three viral pathogens cause acute respiratory tract infections with substantial disease burden in the young, the elderly, and the immune-compromised. While promising subunit vaccines are being developed with prefusion-stabilized forms of the fusion glycoproteins (Fs) of RSV and PIVs, for which neutralizing titers elicited by the prefusion (pre-F) conformation of F are much higher than for the postfusion (post-F) conformation, with HMPV, pre-F and post-F immunogens described thus far elicit similar neutralizing responses, and it has been unclear which conformation, pre-F or post-F, would be the most effective HMPV F-vaccine immunogen. Here, we investigate the impact of further stabilizing HMPV F in the pre-F state. We replaced the furin-cleavage site with a flexible linker, creating a single chain F that yielded increased amounts of pre-F stabilized trimers, enabling the generation and assessment of F trimers stabilized by multiple disulfide bonds. Introduced prolines could increase both expression yields and antigenic recognition by the pre-F specific antibody, MPE8. The cryo-EM structure of a triple disulfide-stabilized pre-F trimer with the variable region of antibody MPE8 at 3.25-Å resolution confirmed the formation of designed disulfides and provided structural details on the MPE8 interface. Immunogenicity assessments in naïve mice showed the triple disulfide-stabilized pre-F trimer could elicit high titer neutralization, >10-fold higher than elicited by post-F. Immunogenicity assessments in pre-exposed rhesus macaques showed the triple disulfide-stabilized pre-F could recall high neutralizing titers after a single immunization, with little discrimination in the recall response between pre-F and post-F immunogens. However, the triple disulfide-stabilized pre-F adsorbed HMPV-directed responses from commercially available pooled human immunoglobulin more fully than post-F. Collectively, these results suggest single-chain triple disulfide-stabilized pre-F trimers to be promising HMPV-vaccine antigens.
Topics: Aged; Humans; Animals; Mice; Metapneumovirus; Macaca mulatta; Antibodies; Respiratory Syncytial Virus, Human; Antigens, Viral; Disulfides; Glycoproteins; Parainfluenza Virus 1, Human
PubMed: 37738240
DOI: 10.1371/journal.ppat.1011584 -
Animal Health Research Reviews Dec 2016Bornaviruses cause neurologic diseases in several species of birds, especially parrots, waterfowl and finches. The characteristic lesions observed in these birds include... (Review)
Review
Bornaviruses cause neurologic diseases in several species of birds, especially parrots, waterfowl and finches. The characteristic lesions observed in these birds include encephalitis and gross dilatation of the anterior stomach - the proventriculus. The disease is thus known as proventricular dilatation disease (PDD). PDD is characterized by extreme proventricular dilatation, blockage of the passage of digesta and consequent death by starvation. There are few clinical resemblances between this and the bornaviral encephalitides observed in mammals. Nevertheless, there are common virus-induced pathogenic pathways shared across this disease spectrum that are explored in this review. Additionally, a review of the literature relating to gastroparesis in humans and the control of gastric mobility in mammals and birds points to several plausible mechanisms by which bornaviral infection may result in extreme proventricular dilatation.
Topics: Animals; Bird Diseases; Birds; Bornaviridae; Dilatation; Mononegavirales Infections; Proventriculus
PubMed: 28155804
DOI: 10.1017/S1466252316000189 -
Viruses Dec 2021All paramyxoviruses, which include the mumps virus, measles virus, Nipah virus, Newcastle disease virus, and Sendai virus, have non-segmented single-stranded... (Review)
Review
All paramyxoviruses, which include the mumps virus, measles virus, Nipah virus, Newcastle disease virus, and Sendai virus, have non-segmented single-stranded negative-sense RNA genomes. These RNA genomes are enwrapped throughout the viral life cycle by nucleoproteins, forming helical nucleocapsids. In addition to these helical structures, recombinant paramyxovirus nucleocapsids may occur in other assembly forms such as rings, clam-shaped structures, and double-headed nucleocapsids; the latter two are composed of two single-stranded helices packed in a back-to-back pattern. In all of these assemblies, the neighboring nucleoprotein protomers adopt the same domain-swapping mode via the N-terminal arm, C-terminal arm, and recently disclosed N-hole. An intrinsically disordered region in the C-terminal domain of the nucleoproteins, called the N-tail, plays an unexpected role in regulating the transition among the different assembly forms that occurs with other viral proteins, especially phosphoprotein. These structures, together with the helical nucleocapsids, significantly enrich the structural diversity of the paramyxovirus nucleocapsids and help explain the functions of these diverse assemblies, including RNA genome protection, transcription, and replication, as well as encapsulation.
Topics: Models, Molecular; Nucleocapsid; Nucleocapsid Proteins; Paramyxovirinae; Protein Conformation; Protein Domains; Protein Structure, Quaternary; Protein Subunits
PubMed: 34960748
DOI: 10.3390/v13122479 -
Viruses Jan 2023The order contains a variety of highly pathogenic viruses that may infect humans, including the families , , , and . Animal models have historically been important to... (Review)
Review
The order contains a variety of highly pathogenic viruses that may infect humans, including the families , , , and . Animal models have historically been important to study virus pathogenicity and to develop medical countermeasures. As these have inherent shortcomings, the rise of microphysiological systems and organoids able to recapitulate hallmarks of the diseases caused by these viruses may have enormous potential to add to or partially replace animal modeling in the future. Indeed, microphysiological systems and organoids are already used in the pharmaceutical R&D pipeline because they are prefigured to overcome the translational gap between model systems and clinical studies. Moreover, they may serve to alleviate ethical concerns related to animal research. In this review, we discuss the value of animal model alternatives in human pathogenic filovirus and bornavirus research. The current animal models and their limitations are presented followed by an overview of existing alternatives, such as organoids and microphysiological systems, which might help answering open research questions.
Topics: Animals; Humans; Filoviridae; Bornaviridae; Models, Animal
PubMed: 36680198
DOI: 10.3390/v15010158 -
Biochimica Et Biophysica Acta.... Dec 2020Viruses reshape the organization of the cell interior to achieve different steps of their cellular cycle. Particularly, viral replication and assembly often take place... (Review)
Review
Viruses reshape the organization of the cell interior to achieve different steps of their cellular cycle. Particularly, viral replication and assembly often take place in viral factories where specific viral and cellular proteins as well as nucleic acids concentrate. Viral factories can be either membrane-delimited or devoid of any cellular membranes. In the latter case, they are referred as membrane-less replication compartments. The most emblematic ones are the Negri bodies, which are inclusion bodies that constitute the hallmark of rabies virus infection. Interestingly, Negri bodies and several other viral replication compartments have been shown to arise from a liquid-liquid phase separation process and, thus, constitute a new class of liquid organelles. This is a paradigm shift in the field of virus replication. Here, we review the different aspects of membrane-less virus replication compartments with a focus on the Mononegavirales order and discuss their interactions with the host cell machineries and the cytoskeleton. We particularly examine the interplay between viral factories and the cellular innate immune response, of which several components also form membrane-less condensates in infected cells.
Topics: Cell Membrane; Inclusion Bodies, Viral; Rabies; Rabies virus; Viral Proteins; Viral Replication Compartments; Virus Replication
PubMed: 32835749
DOI: 10.1016/j.bbamcr.2020.118831 -
The Journal of General Virology Jul 2021Members of the family produce enveloped virions containing a linear negative-sense non-segmented RNA genome of about 9 kb. Bornaviruses are found in mammals, birds,...
Members of the family produce enveloped virions containing a linear negative-sense non-segmented RNA genome of about 9 kb. Bornaviruses are found in mammals, birds, reptiles and fish. The most-studied viruses with public health and veterinary impact are Borna disease virus 1 and variegated squirrel bornavirus 1, both of which cause fatal encephalitis in humans. Several orthobornaviruses cause neurological and intestinal disorders in birds, mostly parrots. Endogenous bornavirus-like sequences occur in the genomes of various animals. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family , which is available at ictv.global/report/bornaviridae.
Topics: Animals; Borna Disease; Borna disease virus; Bornaviridae; Genome, Viral; Host Specificity; Humans; Virion; Virus Replication
PubMed: 34227935
DOI: 10.1099/jgv.0.001613 -
Viruses Jun 2016The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics... (Review)
Review
The highly pathogenic Marburg virus (MARV) is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.
Topics: Marburgvirus; Reverse Genetics; Virology
PubMed: 27338448
DOI: 10.3390/v8060178 -
Methods in Molecular Biology (Clifton,... 2024Ebola (EBOV) and Marburg (MARV) viruses cause hemorrhagic fever disease in humans and non-human primates (NHPs) with case-fatality rates as high as 90%. The 2013-2016...
Ebola (EBOV) and Marburg (MARV) viruses cause hemorrhagic fever disease in humans and non-human primates (NHPs) with case-fatality rates as high as 90%. The 2013-2016 Ebola virus disease (EVD) outbreak led to over 28,000 cases and 11,000 deaths and took an enormous toll on the economy of West African nations, in the absence of any vaccine or therapeutic options. Like EVD, there have been at least 6 outbreaks of MVD with ~88% case-fatality and the most recent cases emerging in Equatorial Guinea in February 2023. These outbreaks have spurred an unprecedented global effort to develop vaccines and therapeutics for EVD and MVD and led to an approved vaccine (ERVEBO™) and two monoclonal antibody (mAb) therapeutics for EBOV. In contrast to EVD, therapeutic options against Marburg and another Ebola-relative Sudan virus (SUDV) are lacking. The filovirus glycoprotein (GP), which mediates host cell entry and fusion, is the primary target of neutralizing antibodies. In addition to its pre- and post-fusion trimeric states, the protein is highly glycosylated making production of pure and homogeneous trimers on a large scale, a requirement for subunit vaccine development, a challenge. In efforts to address this roadblock, we have developed a unique combination of structure-based design, selection of expression system, and purification methods to produce uniform and stable EBOV and MARV GP trimers at scales appropriate for vaccine production.
Topics: Animals; Humans; Hemorrhagic Fever, Ebola; Antibodies, Viral; Ebolavirus; Marburgvirus; Glycoproteins; Vaccines
PubMed: 38315357
DOI: 10.1007/978-1-0716-3666-4_2 -
Current Topics in Microbiology and... 2017The International Committee on Taxonomy of Viruses (ICTV) currently recognizes three genera and seven species as part of the mononegaviral family Filoviridae. Eight... (Review)
Review
The International Committee on Taxonomy of Viruses (ICTV) currently recognizes three genera and seven species as part of the mononegaviral family Filoviridae. Eight distinct filoviruses (Bundibugyo virus, Ebola virus, Lloviu virus, Marburg virus, Ravn virus, Reston virus, Sudan virus, and Taï Forest virus) have been assigned to these seven species. This chapter briefly summarizes the status quo of filovirus classification and focuses on the importance of differentiating between filoviral species and filoviruses and the correct use of taxonomic and vernacular filovirus names and abbreviations in written and oral discourse.
Topics: Ebolavirus; Filoviridae; Marburgvirus; Terminology as Topic
PubMed: 28653188
DOI: 10.1007/82_2017_7 -
Current Topics in Microbiology and... 2017In this chapter, we describe what is known thus far about the structures and functions of the handful of proteins encoded by filovirus genomes. Amongst the fascinating... (Review)
Review
In this chapter, we describe what is known thus far about the structures and functions of the handful of proteins encoded by filovirus genomes. Amongst the fascinating findings of the last decade is the plurality of functions and structures that these polypeptides can adopt. Many of the encoded proteins can play multiple, distinct roles in the virus life cycle, although the mechanisms by which these functions are determined and controlled remain mostly veiled. Further, some filovirus proteins are multistructural: adopting different oligomeric assemblies and sometimes, different tertiary structures to achieve their separate, and equally essential functions. Structures, and the functions they dictate, are described for components of the nucleocapsid, the matrix, and the surface and secreted glycoproteins.
Topics: Filoviridae; Nucleocapsid
PubMed: 28795188
DOI: 10.1007/82_2017_16