Christophe Chevalier

• Ph.D - HDR
• Director of Research at French National Institute for Agriculture, Food, and Environment (INRAE)

PB1-F2 is a non-structural accessory protein of Influenza A virus described to enhance the mortality and the morbidity of the virus in a host-dependent manner. In this work, an electrochemical biosensor based on immunodetection system was developed to follow the oligomerization of PB1-F2 during the viral cycle. Immunosensor was based on conductive...

In this study, subnucleocapsid nanorings formed by the recombinant nucleoprotein (N) of the respiratory syncytial virus were evaluated as a platform to anchor heterologous antigens. The ectodomain of the influenza virus A matrix protein 2 (M2e) is highly conserved and elicits protective antibodies when it is linked to an immunogenic carrier, making...

Influenza A viruses (IAV) remain a major cause of respiratory disease worldwide each year and have been responsible for three main pandemics during the last century comprising the Spanish flu which killed up to 50 million of people. IAV are RNA enveloped viruses belonging to the Orthomyxoviridae family. The nature of the genome of IAV favors the co...

The influenza A virus PB1-F2 protein, encoded by an alternative reading frame in the PB1 polymerase gene, displays a high sequence polymorphism and is reported to contribute to viral pathogenesis in a sequence-specific manner. To gain insights into the functions of PB1-F2, the molecular structure of several PB1-F2 variants produced in Escherichia c...

The cellular form of the prion protein (PrPC), known for its involvement as a misfolded isoform in transmissible spongiform encephalopathies, has recently been identified to exert a protective effect against viral infections. In this study, we explored the role of 2 other prion family members, Shadoo and Doppel, in protection against influenza A vi...

Current poultry vaccines against influenza A viruses target the globular head region of the hemagglutinin (HA1), providing limited protection against antigenically divergent strains. Experimental subunit vaccines based on the conserved ectodomain of the matrix protein 2 (M2e) induce cross-reactive antibody responses, but fail to fully prevent virus...

Deciphering the initial steps of SARS-CoV-2 infection, that influence COVID-19 outcomes, is challenging because animal models do not always reproduce human biological processes and in vitro systems do not recapitulate the histoarchitecture and cellular composition of respiratory tissues. To address this, we developed an innovative ex vivo model of...

Deciphering the initial steps of SARS-CoV-2 infection, that influence COVID-19 outcomes, is challenging because animal models do not always reproduce human biological processes and in vitro systems do not recapitulate the histoarchitecture and cellular composition of respiratory tissues. To address this, we developed an innovative ex vivo model of...

In response to the increasing demand for lung transplantation, ex vivo lung perfusion (EVLP) has extended the number of suitable donor lungs by rehabilitating marginal organs. However despite an expanding use in clinical practice, the responses of the different lung cell types to EVLP are not known. In order to advance our mechanistic understanding...

Most influenza viruses express the PB1-F2 protein which is regarded as a virulence factor. However, PB1-F2 behaves differently in avian and mammalian hosts, suggesting that this protein may be involved in the species barrier crossings regularly observed in influenza viruses. To better understand the functions associated with this viral protein, we...

Influenza virus infection causes considerable morbidity and mortality, but current therapies have limited efficacy. We hypothesized that investigating the metabolic signaling during infection may help to design innovative antiviral approaches. Using bronchoalveolar lavages of infected mice, we here demonstrate that influenza virus induces a major r...

The development of safe and effective vaccines in a record time after the emergence of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a remarkable achievement, partly based on the experience gained from multiple viral outbreaks in the past decades. However, the Coronavirus Disease 2019 (COVID-19) crisis also revealed weaknesses...

Current inactivated vaccines against influenza A viruses (IAV) mainly induce immune responses against highly variable epitopes across strains and are mostly delivered parenterally, limiting the development of an effective mucosal immunity. In this study, we evaluated the potential of intranasal formulations incorporating conserved IAV epitopes, nam...

Influenza A viruses cause important diseases in both human and animal. The PB1-F2 protein is a virulence factor expressed by some influenza viruses. Its deleterious action for the infected host is mostly described in mammals, while the available information is scarce in avian hosts. In this work, we compared the effects of PB1-F2 in avian and mamma...

PB1-F2 is a virulence factor of influenza A virus (IAV) known to increase viral pathogenicity in mammalian hosts. PB1-F2 is an intrinsically disordered protein displaying a propensity to form amyloid-like fibers. However, the correlation between PB1-F2 structures and the resulting inflammatory response is unknown. Here, we used synchrotron-coupled...

Proteinaceous nanostructures have emerged as a promising strategy to develop safe and efficient subunit vaccines. The ability of synthetic β-sheet self-assembling peptides to stabilize antigenic determinants and to potentiate the epitope-specific immune responses have highlighted their potential as an immunostimulating platform for antigen delivery...

PB1-F2 is a non-structural protein of influenza A viruses (IAV) that modulates viral pathogenesis in a host-specific manner. In mammals, this protein has been shown to increase IAV virulence by delaying the early immune response and, eventually, exacerbating lung inflammation at the late stage of infection. PB1-F2 is a small protein, but displays v...

Despite efforts made to develop efficient preventive strategies, infections with influenza A viruses (IAV) continue to cause serious clinical and economic problems. Current licensed human vaccines are mainly inactivated whole virus particles or split-virion administered via the parenteral route. These vaccines provide incomplete protection against...

XCR1 is selectively expressed on a conventional dendritic cell subset, the cDC1 subset, through phylogenetically distant species. The outcome of antigen-targeting to XCR1 may therefore be similar across species, permitting the translation of results from experimental models to human and veterinary applications. Here we evaluated in pigs the immunog...

Highly pathogenic influenza A viruses (IAV) infections represent a serious threat to humans due to their considerable morbidity and mortality capacities. A good understanding of the molecular mechanisms responsible for the acute lung injury observed during this kind of infection is essential to design adapted therapies. In the current study, using...

[This corrects the article on p. 641 in vol. 7, PMID: 28082980.].

PB1-F2 is a viral protein encoded by influenza A viruses (IAVs). PB1-F2 is implicated in virulence by triggering immune cell apoptosis and enhancing inflammation. To obtain an insight into the molecular mechanisms of PB1-F2-mediated virulence, we used the yeast two-hybrid approach to find new PB1-F2 cellular interactors. This allowed us to identify...

Avian Influenza virus (AIV) is a major concern for the global poultry industry. Since 2012, several countries have reported AIV outbreaks among domestic poultry. These outbreaks had tremendous impact on poultry production and socio-economic repercussion on farmers. In addition, the constant emergence of highly pathogenic AIV also poses a significan...

Details of primers used in this study. (XLSX)

Correlation between quantitative PCR of viral copy number and virus titration. MDCK cells were infected with different doses of IAV and subjected to plaque assays for virus titration. The supernatants of the same samples were used to extract viral RNA. After reverse transcription, cDNA were used to determine viral M1 copy number (i.e. segment #8)....

Correlation between quantitative RT-PCR and microarray data. CLEC213 cells were infected by H6N2 virus at a MOI of 2. At 16 hours post-infection, total RNA was extracted from cells and analyzed by microarray or by RT-qPCR. The table provides the mean of data obtained for 4 replicates in each methods. The scatter plot represents the distribution of...

Introduction Human and mouse respiratory tracts show anatomical and physiological differences, making it necessary to develop alternative experimental models for many respiratory diseases study. Pig has been recognized as a valuable biomedical model, in particular for lung transplantation or pathologies such as cystic fibrosis and influenza infecti...

The development of influenza A virus (IAV) vaccines, which elicits cross-strain immunity against seasonal and pandemic viruses is a major public health goal. As pigs are susceptible to human, avian, and swine-adapted IAV, they would be key targets of so called universal IAV vaccines, for reducing both the zoonotic risk and the economic burden in th...

The influenza A virus (IAV) PB1-F2 protein is a virulence factor contributing to the pathogenesis observed during IAV infections in mammals. In this study, using a mouse model, we compared the host response associated with PB1-F2 with an early transcriptomic signature that was previously associated with neutrophils and consecutively fatal IAV infec...

Quantification of the chemokine Cxcl2 and its receptor Cxcr2. qRT-PCR was performed to analyze the impact of PB1-F2 expression on host response. Total RNA isolated from lungs of infected mice (day 2pi) was reverse-transcribed and used to quantify expression of chemokine (C-X-C motif) ligand 2 (Cxcl2, Gene ID: 20310) and its receptor chemokine (C-X-...

PB1-F2 protein is a factor of virulence of influenza A viruses which increases the mortality and morbidity associated with infection. Most seasonal H1N1 Influenza A viruses express nowadays a truncated version of PB1-F2. Here we show that truncation of PB1-F2 modified supramolecular organization of the protein in a membrane-mimicking environment. I...

PB1-F2 is a virulence factor of Influenza A Virus (IAV) whose functions remain misunderstood. The different roles of PB1-F2 may be linked to its structural polymorphism and to its propensity to assemble into oligomers and amyloid fibers in the vicinity of the membrane of IAV-infected cells. Here, we monitored the impact of PB1-F2 on the biochemical...

PB1-F2 is a small accessory protein encoded by an alternative open reading frame in PB1 segments of most influenza A virus. PB1-F2 is involved in virulence by inducing mitochondria mediated immune cells apoptosis, increasing inflammation, and enhancing predisposition to secondary bacterial infections. Using biophysical approaches we characterized m...

Human and mouse respiratory tracts show anatomical and physiological differences, which will benefit from alternative experimental models for studying many respiratory diseases. Pig has been recognized as a valuable biomedical model, particularly for lung transplantation or pathologies such as cystic fibrosis and influenza infection. However, there...

ZnMgO nanoparticles have shown potential for medical applications as an efficient antibacterial agent. In this work, we investigate the effect of water and two commonly used cell culture media on the physicochemical properties of ZnMgO nanoparticles in correlation with their cytotoxicity. In vacuum, ZnMgO nanopowder consists of MgO (nanocubes) and...

Highly pathogenic avian influenza virus (HPAIV) is a permanent threat due to its capacity to cross species barriers and generate severe infections and high mortality in humans. Recent findings have highlighted the potential role of PB1-F2, a small accessory influenza protein, in the pathogenesis process mediated by HPAIV in mammals. In this study,...

Lipid membrane can enhance prion protein (PrP) pathological fibrillogenesis.A neuronal paralog of PrP, namedShadoo (Sho), is localized to similar membrane environment as PrPand can also convert to amyloid-like fibrilles.To gain insight into the role of Shoin prion diseases, we studied Sho interactionswith cellular membrane models. Showas found to b...

The PB1-F2 protein encoded by influenza A viruses can contribute to virulence, a feature that is dependent of its sequence polymorphism. Whereas PB1-F2 from some H1N1 viruses were shown to exacerbate the inflammatory response within the airways, the contribution of PB1-F2 to highly pathogenic avian influenza virus (HPAIV) virulence in mammals remai...

Sequences of Influenza A/duck/Niger/2090/2006 (H5N1) virus in Fasta format. (TXT)

The detection and evaluation of concentration of influenza virus proteins in biological samples is critical in a broad range of medical and biological investigations regarding the concern over potential outbreaks of virulent influenza strains in animals and humans. This paper describes a sensitive, label-free approach for the detection of a virulen...

In this study, we developed a large-scale screening of bacterial strains in order to identify novel candidate probiotics with immunomodulatory properties. For this, 158 strains, including a majority of lactic acid bacteria (LAB), were screened by two different cellular models: tumor necrosis factor alpha (TNF-α)-activated HT-29 cells and peripheral...

The influenza viruses contain a segmented, negative stranded RNA genome. Each RNA segment is covered by multiple copies of the nucleoprotein (NP). X-ray structures have shown that NP contains well-structured domains juxtaposed with regions of missing electron densities corresponding to loops. In this study, we tested if these flexible loops gated o...

Lipid membrane can enhance prion protein (PrP) pathological fibrillogenesis. A neuronal paralog of PrP, named Shadoo (Sho), is localized to similar membrane environment as PrP and can also convert to amy-loid-like fibrilles. To gain insight into the role of Sho in prion diseases, we studied Sho interactions with cellular membrane models. Sho was fo...

The influenza viruses contain a segmented, negative strand RNA genome. Each RNA segment is covered by multiple copies of the nucleoprotein (NP) and is associated with the polymerase complex into ribonucleoprotein (RNP) particles. Despite its importance in the virus life cycle, the interactions between the NP and the genome are not well understood....

(A) Table depicting ORF phenotypic summary of segment 2 WSN mutants (adapted from Wise et al. J Virol. 2009.). We used the 12 plasmids reverse genetics system to generate recombinant viruses containing mutations on the segment 2. ΔF2: the initiation and the three in-frame ATG codons of the ORF were mutated to ACG, Stop12: a stop codon were introduc...

Impact of PB1-F2 expression on several inflammatory markers. Total RNA isolated from lungs of infected mice (day 2 pi) were reverse-transcribed and used to quantify expression of several inflammatory markers by qPCR :chemokine (C-C motif) receptor 1 (Ccr1, Gene ID: 12768), chemokine (C-X-C motif) ligand 1 (Cxcl1, Gene ID:14825), colony stimulating...

Positive control of luminescence emission from BALB/c mice intranasally instillated with 2.5×108 PFU of Ad-NF-κB-luc. Mice were anesthetized by a mixture of ketamine and xylazine (1 and 0.2 mg per mouse, respectively) and infected intranasally with 50 µl of PBS containing 2.5×108 PFU of Ad-NF-κB-luc. 24 hours postinhalation, mice were stimulated wi...

In vivo kinetics of PB1-F2 expression in IAV-infected mice lungs. Expressions of PB1-F2 and β-actin were monitored by Western blot analysis (Fig1A). β-actin was used as an internal control to standardize protein levels. Band intensities on blots were quantified using Image J software (http://rsbweb.nih.gov/ij/). The value for PB1-F2 are normalized...

Infectivity of WT and ΔF2 viruses in lungs. (A) Mice were infected by 1.5×105 PFU or mock-infected and were sacrificed at day 2 pi. Lungs were dissected and inflated using cryomatrix fluid. Paraformaldehyde-fixed cryosections were then labeled with an anti-NS1 antibody (Santa Cruz Biotechnology) and nuclei were counterstained with DAPI. (B) Quantif...

Airway inflammation plays a major role in the pathogenesis of influenza viruses and can lead to a fatal outcome. One of the challenging objectives in the field of influenza research is the identification of the molecular bases associated to the immunopathological disorders developed during infection. While its precise function in the virus cycle is...

The PB1-F2 protein of the influenza A virus (IAV) contributes to viral pathogenesis by a mechanism that is not well understood. PB1-F2 was shown to modulate apoptosis and to be targeted by the CD8(+) T cell response. In this study, we examined the downstream effects of PB1-F2 protein during IAV infection by measuring expression of the cellular gene...

Infectious pancreatic necrosis virus (IPNV), a pathogen of salmon and trout, imposes a severe toll on the aquaculture and sea farming industries. IPNV belongs to the Aquabirnavirus genus in the Birnaviridae family of bisegmented double-stranded RNA viruses. The virions are nonenveloped with a T=13l icosahedral capsid made by the coat protein VP2, t...

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and hepatocellular carcinoma, yet fully efficacious treatments are missing. In this study, we investigated RNA interference (RNAi), a specific gene silencing process mediated by small interfering RNA (siRNA) duplexes, as an antiviral strategy against HCV. Synthetic siRNAs w...

Les particules des virus à ARN double brin (ARNdb) sont compétentes pour la transcription et doivent traverser une membrane cellulaire pour fonctionner dans le cytoplasme de la cellule cible. Parmi ces virus, les birnavirus sont singuliers car ils possèdent une simple capside icosaédrique de triangulation T = 13 et ne contiennent pas la capside int...

Birnaviruses possess a capsid with a single protein layer in contrast to most double-stranded RNA viruses infecting multicellular eukaryotes. Using freeze-drying and heavy metal shadowing, the capsids of two birnaviruses, infectious bursal disease virus (IBDV) and infectious pancreatic necrosis virus, as well as of an IBDV virus-like particle (VLP)...

Double-stranded RNA virions are transcriptionally competent icosahedral particles that must translocate across a lipid bilayer to function within the cytoplasm of the target cell. Birnaviruses are unique among dsRNA viruses as they have a single T = 13 icosahedral shell, lacking the characteristic inner capsid observed in the others. We determined...

The capsid of infectious bursal disease virus (IBDV), a nonenveloped virus of the family Birnaviridae, has a T=13l icosahedral shell constituted by a single protein, VP2, and several disordered peptides, all derived from the precursor pVP2. In this study, we show that two of the peptides, pep11 and pep46, control virus assembly and cell entry. Dele...

The capsid of birnaviruses contains two proteins, VP2 and VP3, which derive from the processing of a large polyprotein, NH(2)-pVP2-VP4-VP3-COOH. The proteolytic cascade involved in processing the polyprotein, and in the final maturation of pVP2 (the precursor of VP2), has recently been shown to generate VP2 and four structural peptides in infectiou...

To develop a CELO virus vector that can induce protection against infectious bursal disease, CELO viruses expressing the host-protective antigen VP2 of infectious bursal disease virus (IBDV) were constructed. In the engineered recombinants, the VP2 gene (the 441-first codons of the IBDA polyprotein) was placed under the control of the CMV promoter....

Infectious bursal disease virus (IBDV) is a nonenveloped virus with an icosahedral capsid composed of two proteins, VP2 and VP3, that derive from the processing of the polyprotein NH(2)-pVP2-VP4-VP3-COOH. The virion contains VP1, the viral polymerase, which is both free and covalently linked to the two double-stranded RNA (dsRNA) genomic segments....

By different approaches, we characterized the birnavirus blotched snakehead virus (BSNV). The sequence of genomic segment A revealed the presence of two open reading frames (ORFs): a large ORF with a 3,207-bp-long nucleotide sequence and a 417-nucleotide-long small ORF located within the N-terminal half of the large ORF, but in a different reading...

Infectious bursal disease virus (IBDV) is a nonenveloped avian virus with a two-segment double-stranded RNA genome. Its T=13 icosahedral capsid is most probably assembled with 780 subunits of VP2 and 600 copies of VP3 and has a diameter of about 60 nm. VP1, the RNA-dependent RNA polymerase, resides inside the viral particle. Using a baculovirus exp...

The capsid proteins VP2 and VP3 of infectious bursal disease virus, a birnavirus, are derived from the processing of a large polyprotein: NH2-pVP2-VP4-VP3-COOH. Although the primary cleavage sites at the pVP2-VP4 and VP4-VP3 junctions have been identified, the proteolytic cascade involved in the processing of this polyprotein is not yet fully under...

L'expression des protéines de capside d'un virus non enveloppé aboutit généralement à leur auto-assemblage en pseudo-particules virales dont la géométrie est semblable à celle du virus. Les birnavirus constituent une exception à cette règle. Le virus de la bursite infectieuse aviaire (IBDV) appartient à cette famille de virus. Il est responsable de...