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At least 19 recordsLinked to original sources
PubMed2003

Deduced amino acid sequence of the small hydrophobic protein of US avian pneumovirus has greater identity with that of human metapneumovirus than those of non-US avian pneumoviruses.

We report here the nucleotide and deduced amino acid (aa) sequences of the small hydrophobic (SH) gene of the avian pneumovirus strain Colorado (APV/CO). The SH gene of APV/CO is 628 nucleotides in length from gene-start to gene-end. The longest ORF of the SH gene encoded a protein of 177 aas in length. Comparison of the deduced aa sequence of the SH protein of APV/CO with the corresponding published sequences of other members of genera metapneumovirus showed 28% identity with the newly discovered human metapneumovirus (hMPV), but no discernable identity with the APV subgroup A or B. Collectively, this data supports the hypothesis that: (i) APV/CO is distinct from European APV subgroups and belongs to the novel subgroup APV/C (APV/US); (ii) APV/CO is more closely related to hMPV, a mammalian metapneumovirus, than to either APV subgroup A or B. The SH gene of APV/CO was cloned using a genomic walk strategy which initiated cDNA synthesis from genomic RNA that traversed the genes in the order 3'-M-F-M2-SH-G-5', thus confirming that gene-order of APV/CO conforms in the genus Metapneumovirus. We also provide the sequences of transcription-signals and the M-F, F-M2, M2-SH and SH-G intergenic regions of APV/CO.

Amino Acid Sequence↗
PubMed1994

Extensive sequence variation in the attachment (G) protein gene of avian pneumovirus: evidence for two distinct subgroups.

The putative attachment protein of the avian pneumovirus that causes turkey rhinotracheitis is, by analogy with mammalian pneumoviruses, expected to be the major antigenic determinant. We report the nucleotide sequence of the attachment (G) protein genes of five different continental European isolates and compare them with the previously published sequence of the G gene for the focal variant of a U.K. isolate. The nucleotide sequences and the predicted amino acid sequences indicate that there are at least two distinct subgroups, similar to the grouping described for human respiratory syncytial (RS) virus. The U.K. and French isolates form one group and the isolates from Spain, Italy and Hungary form a second. The two subgroups can be easily distinguished on the basis of restriction enzyme digestion of PCR-generated products representing the full-length gene. Within the subgroups the predicted G proteins were highly conserved (98.5 to 99.7% amino acid identity) compared to the levels of identity of RS virus G proteins in the same subgroup (80 to 95%). Between the avian pneumovirus subgroups described here there was an unexpected degree of divergence, the average amino acid identity between members of the two groups being only 38%. This compares with the 53% conservation seen between members of the RS virus subgroups A and B. Comparison of the predicted amino acid sequences showed that the G proteins of members of the two avian pneumovirus subgroups had similar structural features. All proteins had an amino-terminal membrane anchor and the positions of cysteine residues were highly conserved. The potential importance of the high level of variation between the two subgroups in terms of epidemiology of the disease is discussed.

Amino Acid Sequence↗
PubMed2004

Animal pneumoviruses: molecular genetics and pathogenesis.

Pneumoviruses are single-stranded, negative-sense, nonsegmented RNA viruses of the family Paramyxoviridae, subfamily Pneumovirinae, and include pathogens that infect humans (respiratory syncytial virus and human metapneumovirus), domestic mammals (bovine, ovine, and caprine respiratory syncytial viruses), rodents (pneumonia virus of mice), and birds (avian metapneumovirus). Among the topics considered in this review are recent studies focused on the roles of the individual virus-encoded components in promoting virus replication as well as in altering and evading innate antiviral host defenses. Advances in the molecular technology of pneumoviruses and the emergence of recombinant pneumoviruses that are leading to improved virus-based vaccine formulations are also discussed. Since pneumovirus infection in natural hosts is associated with a profound inflammatory response that persists despite adequate antiviral therapy, we also review the recent experimental treatment strategies that have focused on combined antiviral, anti-inflammatory, and immunomodulatory approaches.

Animals↗
PubMed2000

Duration of cross-protection between subtypes A and B avian pneumovirus in turkeys.

The degree and duration of clinical and virological cross-protection between avian pneumovirus subtypes A and B were examined in two-week-old pneumovirus antibody-free turkeys. The turkeys were inoculated with either a virulent subtype A (Belgian isolate A/T6/96), a virulent subtype B (Belgian isolate B/T9/96), an attenuated subtype A or an attenuated subtype B, and challenged homologously and heterologously with virulent avian pneumovirus two, five and 11 weeks after inoculation. Birds inoculated with virulent A or B virus showed typical respiratory signs from three to seven days after inoculation. After challenge, no clinical signs were observed in any of the groups, and no virus was isolated from the turkeys that had been initially inoculated with a virulent strain. Virulent virus was recovered from the birds that had been initially inoculated with attenuated subtypes and challenged five and/or 11 weeks later with a heterologous virulent strain. Birds challenged after five weeks showed a serological booster reaction only when they had been inoculated initially with a virulent or attenuated subtype B and challenged with subtype A. Seroconversion was observed in all the groups challenged after 11 weeks except when they had been inoculated initially with attenuated subtype B and challenged with subtype B.

Animals↗
PubMedDate not supplied

The sensitivity and specificity of a reverse transcription-polymerase chain reaction assay for the avian pneumovirus (Colorado strain).

A reverse transcription-polymerase chain reaction (RT-PCR) assay for the detection of avian pneumovirus (APV), Colorado strain (US/CO), was evaluated for sensitivity and specificity. The single-tube RT-PCR assay utilized primers developed from the matrix (M) gene sequence of the US/CO APV. The RT-PCR amplified the US/CO APV but did not amplify other pneumoviruses, including the avian pneumoviruses subgroups A and B. The RT-PCR was capable of detecting between 10(0.25) mean tissue culture infective dose (TCID50) and 10(-0.44) TCID50 of the US/CO APV. These results have demonstrated that the single-tube RT-PCR assay is a specific and sensitive assay for the detection of US/CO APV.

Animals↗
PubMedDate not supplied

Serologic evidence of pneumovirus in Chile.

Chicken and turkey serum samples were obtained and tested in an enzyme-linked immunosorbent assay to establish the presence or absence of antibodies to avian pneumovirus in the commercial poultry population of Chile. A total of 600 serum samples representing 15 different poultry farms of the central region of Chile were considered. These samples were obtained from 52 different flocks and included 220 turkey and 380 chicken sera. The results showed three flocks of market turkeys belonging to the same farm and three flocks of laying chickens of three different farms to be positive to antibody against pneumovirus. These results provide serologic evidence for the presence of pneumovirus in Chilean poultry.

Animal Husbandry↗
PubMed2001

Glucocorticoid administration accelerates mortality of pneumovirus-infected mice.

The use of glucocorticoids for the treatment of symptoms associated with respiratory syncytial virus (RSV) infection has been questioned. To evaluate the sequelae of glucocorticoid administration in the setting of pneumovirus infection in vivo, hydrocortisone was administered to mice infected with pneumonia virus of mice (PVM), a pneumovirus and natural rodent pathogen that is closely related to RSV and replicates the signs and symptoms of severe human RSV infection. Results showed that hydrocortisone spared the pulmonary neutrophilia but resulted in ablation of the pulmonary eosinophilia, despite continued production of the relevant chemoattractant, macrophage inflammatory protein-1alpha. Hydrocortisone also led to diminished production of inducible nitric oxide synthase and accumulation of reactive nitrogen species in lung tissue and bronchoalveolar lavage fluid and diminished lymphocyte recruitment. PVM-infected mice responded to hydrocortisone with enhanced viral replication and accelerated mortality. These results suggest several mechanisms to explain why glucocorticoid therapy may be of limited benefit in the overall picture of pneumovirus infection.

Animals↗
PubMed1996

Nucleotide sequence of the gene encoding the viral polymerase of avian pneumovirus.

We report here the nucleotide sequence of the L gene of avian pneumovirus (APV). This is the second pneumovirus L gene and the second avian paramyxovirus L gene, following that of Newcastle disease virus, to be sequenced. The APV L gene is 6099 nucleotides long and encodes a single large ORF of 2004 amino acids. This makes the APV L protein the smallest to be described for any nonsegmented, negative-strand RNA virus. The protein contains six linear non-contiguous domains, a putative ATP-binding site and four polymerase motifs previously described for the L proteins of negative-strand RNA viruses. Phylogenetic analysis of domain III of 14 different L proteins suggests the pneumoviruses to be as distant in evolutionary terms from the other members of the Paramyxoviridae as are the Filoviridae.

Amino Acid Sequence↗
PubMed2001

Fidelity of leader and trailer sequence usage by the respiratory syncytial virus and avian pneumovirus replication complexes.

The specificity of usage of promoters for replication and transcription by the pneumoviruses human respiratory syncytial virus (HRSV) and avian pneumovirus (APV) was studied using minigenomes containing a reporter gene. When infectious HRSV or APV was used as helper virus, replication could occur only if both the leader and trailer regions (containing the replicative and transcriptional promoters) were derived from the helper virus. In contrast, when the HRSV replication complex was supplied from cDNA plasmids, a minigenome containing either the APV leader or trailer was recognized and substantial levels of replication and transcription occurred. These data suggest that in pneumovirus-infected cells, helper virus functions can discriminate between genomes on the basis of the terminal sequences and that there is an association between the leader and trailer required for productive replication. This association is required only in virus-infected cells, not when replication and transcription are mediated by plasmid-directed expression of the component proteins required for replication and transcription. The possible implications of this are discussed.

Animals↗
PubMed2006

Mucosal inoculation with an attenuated mouse pneumovirus strain protects against virulent challenge in wild type and interferon-gamma receptor deficient mice.

Protective mechanisms underlying the responses to mucosal vaccination are not yet clearly defined. Using the natural mouse pneumovirus pathogen, pneumonia virus of mice (PVM), we explore responses of wild type and interferon-gamma (IFNgamma) receptor gene-deleted mice to virulent challenge after mucosal vaccination with an attenuated virus strain. Serum neutralizing antibodies develop after intranasal inoculation with 30 pfu of attenuated, replication-competent PVM strain 15, which correlate with diminished gross and microscopic pulmonary pathology and protection from weight loss in response to subsequent challenge with the virulent parent PVM strain J3666. Virus replication in response to challenge was blunted in PVM strain 15 vaccinated mice, as was local production of secretory mediators IFNgamma, TNF-alpha, MIP-1 alpha, and MIP-2. Interestingly, responses of vaccinated IFNgamma receptor gene-deleted mice were indistinguishable from those of the wild type, suggesting that IFNgamma signaling may not be crucial for the generation of adaptive responses to pneumovirus infection in vivo.

Animals↗
PubMed2003

Regulation of host cell transcriptional physiology by the avian pneumovirus provides key insights into host-pathogen interactions.

Infection with a viral pathogen triggers several pathways in the host cell that are crucial to eliminating infection, as well as those that are used by the virus to enhance its replication and virulence. We have here used suppression subtractive hybridization and cDNA microarray analyses to characterize the host transcriptional response in an avian pneumovirus model of infection. The results of our investigations reveal a dynamic host response that includes the regulation of genes with roles in a vast array of cellular functions as well as those that have not been described previously. The results show a considerable upregulation in transcripts representing the interferon-activated family of genes, predicted to play a role in virus replication arrest. The analysis also identified transcripts for proinflammatory leukocyte chemoattractants, adhesion molecules, and complement that were upregulated and may account for the inflammatory pathology that is the hallmark of viral respiratory infection. Interestingly, alterations in the transcription of several genes in the ubiquitin and endosomal protein trafficking pathways were observed, suggesting a role for these pathways in virus maturation and budding. Taken together, the results of our investigations provide key insights into individual genes and pathways that constitute the host cell's response to avian pneumovirus infection, and they have enabled the development of resources and a model of host-pathogen interaction for an important avian respiratory tract pathogen.

Amino Acid Sequence↗
PubMed2001

Immunohistochemical detection of avian pneumovirus in formalin-fixed tissues.

An immunohistochemical staining technique (IHC) was developed to detect avian pneumovirus (APV) antigen in formalin-fixed, paraffin-embedded tissue sections using streptavidin-biotin immunoperoxidase staining. Samples of nasal turbinates and infraorbital sinuses were collected from 4-week-old poults experimentally inoculated with APV and from older turkeys infected during naturally occurring outbreaks of avian pneumovirus. Tissue was fixed in 10% buffered neutral formalin, embedded in paraffin, sectioned and stained. Inflammatory changes were observed microscopically in the mucosa and submucosa of the nasal turbinates and infraorbital sinuses of both experimentally inoculated poults and naturally infected birds. Viral antigen was detected by IHC in the ciliated epithelial cells of nasal turbinates and infraorbital sinuses.

Animals↗
PubMed2001

PCR-based detection of an emerging avian pneumovirus in US turkey flocks.

Avian pneumovirus (APV) or turkey rhinotracheitis virus (TRTV) is an important respiratory pathogen of domesticated poultry in many countries in Europe, Africa, and Asia. Until recently, the United States was considered free of APV. In late 1996, an atypical upper respiratory tract infection appeared in turkey flocks in Colorado and shortly thereafter in turkey flocks in Minnesota. An avian pneumovirus (APV-US) that was serologically distinct from the previously described TRTV was isolated as the primary cause of the new syndrome. The nucleotide sequence of a fragment of the APV-US fusion gene was determined and used to develop a polymerase chain reaction-based assay that specifically detects APV-US viral nucleic acid sequences in RNA extracts of tracheal swabs and turbinate homogenates. The assay is highly sensitive in that it can detect <0.01 TCID50 of APV. The availability of this assay enables the rapid and accurate determination of APV-US in infected poultry flocks.

Animals↗
PubMed2005

Activation and inactivation of antiviral CD8 T cell responses during murine pneumovirus infection.

Pneumonia virus of mice (PVM) is a natural pathogen of mice and has been proposed as a tractable model for the replication of a pneumovirus in its natural host, which mimics human infection with human respiratory syncytial virus (RSV). PVM infection in mice is highly productive in terms of virus production compared with the situation seen with RSV in mice. Because RSV suppresses CD8 T cell effector function in the lungs of infected mice, we have investigated the nature of PVM-induced CD8 T cell responses to study pneumovirus-induced T cell responses in a natural virus-host setting. PVM infection was associated with a massive influx of activated CD8 T cells into the lungs. After identification of three PVM-specific CD8 T cell epitopes, pulmonary CD8 T cell responses were enumerated. The combined frequency of cytokine-secreting CD8 T cells specific for the three epitopes was much smaller than the total number of activated CD8 T cells. Furthermore, quantitation of the CD8 T cell response against one of these epitopes (residues 261-270 from the phosphoprotein) by MHC class I pentamer staining and by in vitro stimulation followed by intracellular IFN-gamma and TNF-alpha staining indicated that the majority of pulmonary CD8 specific for the P261 epitope were deficient in cytokine production. This deficient phenotype was retained up to 96 days postinfection, similar to the situation in the lungs of human RSV-infected mice. The data suggest that PVM suppresses T cell effector functions in the lungs.

Amino Acid Sequence↗
PubMedDate not supplied

Avian pneumovirus infection in Minnesota turkeys: experimental reproduction of the disease.

Avian pneumovirus (APV) is an emerging viral respiratory disease agent of turkeys in Minnesota. Clinical signs of APV infection include open mouth breathing, ocular and nasal discharge, and swelling of infraorbital sinuses. The virus spreads rapidly among flocks of susceptible turkeys and is associated with increased mortality rates. A flock of 11-wk-old turkeys experienced a respiratory problem characterized by coughing, sneezing, swollen sinuses, and nasal discharge. The reverse transcriptase-polymerase chain reaction (RT-PCR) performed on tissues from the nasal turbinates and tracheal tissues was positive for avian pneumovirus. Turbinate tissue was inoculated into chicken embryo fibroblasts, and cytopathic effect was observed after five blind passages. In an attempt to reproduce the disease, 50 microl of this cell culture-propagated virus was instilled into each conjunctival space and nostril of 23-day-old turkey poults. The poults were sacrificed at 2-day intervals for 12 days, and serum, tissues, and tracheal and cloacal swabs were collected. Between days 2 and 10 after exposure, the poults developed ocular and nasal discharge and swollen sinuses. The virus was detected by RT-PCR and virus isolation from the nasal turbinates of poults sacrificed on days 4 and 6 postinoculation. Antibodies to APV were detected by enzyme-linked immunosorbent assay.

Animals↗
PubMed1996

Nucleotide sequence of the matrix protein gene of a subgroup B avian pneumovirus.

The nucleotide sequence of the gene encoding the matrix protein of a subgroup B avian pneumovirus has been determined. The gene shows 73.5% homology with that of a subgroup A virus, with most differences occurring in the third codon position. Comparison with pneumovirus matrix proteins shows that the APV matrix protein retains the hydrophobic domain common to the others. The analysis indicates that the matrix protein gene can be used to differentiate the two APV subgroups.

Amino Acid Sequence↗
PubMed1995

Sequence and in vitro expression of the phosphoprotein gene of avian pneumovirus.

The phosphoprotein (P) gene of two subgroup A strains of avian pneumovirus comprised 855 nucleotides containing only one substantial open reading frame encoding a protein of 278 amino acids, with a predicted M(r) of 30,323. In vitro translation of P mRNA in a wheat germ system resulted in the synthesis of two polypeptides of M(r) 35,000. Comparison of the deduced P protein sequence with that of the known mammalian pneumoviruses revealed overall amino acid identities ranging from 31 to 34.5%, suggesting a distant relationship. However, there was a much higher identity (63.2-68.4%) in a region of 57 residues, which included a heptad repeat sequence.

Amino Acid Sequence↗
PubMed2006

Suppression of pattern-recognition receptor TLR4 sensing does not alter lung responses to pneumovirus infection.

Toll-like receptors (TLR) are an important component in the innate immune response to a wide variety of pathogens. Recently, a series of studies has addressed the hypothesis that TLR4 also participates in the host innate response against respiratory syncytial virus (RSV), the leading cause of lower respiratory tract infections in infants and young children. In most of the studies available, RSV, which is not a natural pathogen of mice, has been systematically used in mouse models of human bronchiolitis, with conflicting results. Pneumonia virus of mice (PVM), a member of the pneumovirus genus, shares many similarities with RSV. The serological and structural relationships that exist between them suggest that the immune response to these viruses may be similar in their respective natural hosts. To determine the role of TLR4 in host defense against PVM, TLR4-competent and TLR4-deficient mice were intranasally infected with PVM. Variation of body weight, pulmonary function values, histopathology, and pulmonary viral loads were analyzed. None of the investigated clinical, functional, histological and virological parameters was different between strains, which demonstrates that the sensitivity of the mouse to its natural pneumovirus infection is independent of the presence or absence of TLR4 sensing.

Animals↗