Viral infection triggers host innate immune responses through cellular sensor molecules which activate multiple signaling cascades that induce the production of interferons (IFN) and other cytokines. The recent identification mammalian cytoplasmic viral RNA sensors, such as retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) their mitochondrial adaptor, antiviral protein (MAVS), also called IPS-1, VISA, Cardif, highlights significance these in induction IFN. Teleost fish possess a...

Human metapneumovirus (HMPV) has recently been identified as a significant cause of serious respiratory tract disease in humans. In particular, the emerging information on contribution HMPV to pediatric suggests that it will be important develop vaccine against this virus for use conjunction with those being developed human syncytial and parainfluenza viruses. A described reverse genetic system (S. Biacchesi, M. H. Skiadopoulos, K. C. Tran, B. R. Murphy, P. L. Collins, U. J. Buchholz,...

The growth properties and antigenic relatedness of the CAN98-75 (CAN75) CAN97-83 (CAN83) human metapneumovirus (HMPV) strains, which represent two distinct HMPV genetic lineages exhibit 5 63% amino acid divergence in fusion (F) attachment (G) proteins, respectively, were investigated vitro rodents nonhuman primates. Both strains replicated to high titers (> or =6.0 log(10)) upper respiratory tract hamsters moderate =3.6 lower tract. exhibited 48% based on reciprocal cross-neutralization...

ABSTRACT Recombinant human metapneumovirus (HMPV) in which the SH, G, or M2 gene open reading frame was deleted by reverse genetics evaluated for replication and vaccine efficacy following topical administration to respiratory tract of African green monkeys, a permissive primate host. Replication ΔSH virus only marginally less efficient than that wild-type HMPV, whereas ΔG ΔM2-2 viruses were reduced sixfold 160-fold upper 3,200-fold 4,000-fold lower tract, respectively. Even with highly...

Viral infections are detected in most cases by the host innate immune system through pattern-recognition receptors (PRR), sensors for pathogen-associated molecular patterns (PAMPs), which induce production of cytokines, such as type I interferons (IFN). Recent identification mammalian and teleost fish cytoplasmic viral RNA sensors, RIG-I-like (RLRs), their mitochondrial adaptor: antiviral signaling (MAVS) protein, also called IPS-1, highlight important role induction IFN at early stage a...

The M2 gene of human metapneumovirus (HMPV) contains two overlapping open reading frames (ORFs), M2-1 and M2-2. expression separate M2-2 proteins from these ORFs was confirmed, recombinant HMPVs were recovered in which ablated individually or together [rdeltaM2-1, rdeltaM2-2, rdeltaM2(1+2)]. Each mutant virus directed efficient multicycle growth Vero cells. ability to recover HMPV lacking contrasts with respiratory syncytial virus, for is an essential transcription factor. Expression the...

Abstract Non virion (NV) protein expression is critical for fish Novirhabdovirus, viral hemorrhagic septicemia virus (VHSV) and infectious hematopoietic necrosis (IHNV), in vivo pathogenesis. However, the mechanism by which NV promotes replication still unclear. We developed an approach based on reverse genetics interactomic identified several NV-associated cellular partners underlying pathways as potential targets. Among these cell partners, we showed that proteins specifically interact...

ABSTRACT Infectious hematopoietic necrosis virus (IHNV) is a Novirhabdovirus and the causative agent of devastating acute, lethal disease in wild farmed rainbow trout. The enzootic throughout western North America has spread to Asia Europe. A full-length cDNA IHNV antigenome (pIHNV-Pst) was assembled from subgenomic overlapping fragments cloned transcription plasmid between T7 RNA polymerase promoter autocatalytic hepatitis delta ribozyme. Recombinant (rIHNV) recovered fish cells at 14°C,...

Viral hemorrhagic septicemia virus (VHSV) is a highly contagious leading to high mortality in large panel of freshwater and marine fish species. VHSV isolates originating from show low pathogenicity rainbow trout. The analysis several nearly complete genome sequences displaying varying levels virulence trout suggested that only limited number amino acid residues might be involved regulating the level virulence. Based on recent 55 strains, which were entirely sequenced phenotyped vivo trout,...

ABSTRACT The genome sequence of a hypervirulent novirhabdovirus, viral hemorrhagic septicemia virus (VHSV) French strain 23-75, was determined. Compared to the prototype Fil3 strain, number substitutions, deletions, and insertions were observed. Following establishment plasmid-based minigenome replication assay, recombinant VHSV (rVHSV) successfully recovered. rVHSV exhibits wild-type-like growth properties in vitro as well vivo rainbow trout. dispensable role NV for novirhabdovirus...

We previously reported that betanodavirus reassortant strains [redspotted grouper nervous necrosis virus/striped jack virus (SJNNV)] isolated from Senegalese sole (Solea senegalensis) exhibited a modified SJNNV capsid amino acid sequence, with changes at aa 247 and 270. In the current study, we investigated possible role of both residues as putative virulence determinants. Three recombinant viruses harbouring site-specific mutations in protein rSs160.03247 (S247A), rSs160.03270 (S270N)...

The genome of infectious hematopoietic necrosis virus (IHNV), a salmonid novirhabdovirus, has been engineered to modify the gene order and evaluate impact on possible attenuation in vitro vivo By reverse genetics, eight recombinant IHNVs (rIHNVs), termed NxGy according respective positions nucleoprotein (N) glycoprotein (G) genes along genome, have recovered. All rIHNVs fully characterized for their cytopathic effects, kinetics replication, profiles viral transcription. These are stable...

Chimeric versions of recombinant human metapneumovirus (HMPV) were generated by replacing the nucleoprotein (N) or phosphoprotein (P) open reading frame with its counterpart from closely related avian (AMPV) subgroup C. In Vero cells, AMPV replicated to an approximately 100-fold-higher titer than HMPV. Surprisingly, N and P chimeric viruses a peak that was 11- 25-fold higher, respectively, parental The basis for this effect is not known but due obvious changes in efficiency gene expression....

The contribution of cleavage activation the fusion F protein human metapneumovirus (HMPV) to replication and pathogenicity in rodents nonhuman primates was investigated. Recombinant HMPVs were generated which naturally occurring trypsin-dependent sequence (R-Q-S-R downward arrow) replaced by each three sequences whose vitro does not depend upon added trypsin. Two these multibasic derived from avian type A (R-R-R-R) or C (R-K-A-R), with former containing consensus furin protease motif...

Viral hemorrhagic septicaemia virus (VHSV) is an important viral pathogen in European rainbow trout farming. Isolates from wild marine fish and freshwater farms show highly different virulence profiles: isolates species cause little or no mortality following experimental waterborne challenge, whilst challenge with results high levels of mortality. Phylogenetic analyses have revealed that the virulent trout-derived evolved VHSV host over past 60 years. Recent reared zones intermediate...

Infectious hematopoietic necrosis virus (IHNV) and viral hemorrhagic septicemia (VHSV) are two salmonid rhabdoviruses replicating at low temperatures (14 to 20 degrees C). Both viruses belong the Novirhabdovirus genus, but they only distantly related do not cross antigenically. By using a recently developed reverse-genetic system based on IHNV (S. Biacchesi et al., J. Virol. 74:11247-11253, 2000), we investigated ability exchange glycoprotein G with that of VHSV. Thus, genome was modified so...

During the preparation of recombinant derivatives CAN97-83 clinical isolate human metapneumovirus (HMPV), consensus nucleotide sequencing recovered RNA genomes provided evidence frequent sequence heterogeneity at a number genome positions. This was suggestive sizable subpopulations containing mutations. An analysis molecularly cloned cDNAs confirmed presence mixed populations. The biologically derived virus on which system is based also contained sizeable mutant subpopulations, whose by...