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Intervirology 2018Human metapneumovirus (hMPV) is an important human respiratory pathogen and is implicated in an array of respiratory illnesses, ranging from asymptomatic infection to...
BACKGROUND/AIMS
Human metapneumovirus (hMPV) is an important human respiratory pathogen and is implicated in an array of respiratory illnesses, ranging from asymptomatic infection to severe bronchiolitis. Currently, there is no reliable vaccine or specific antiviral therapy for hMPV infection and treatment is supportive. The use of ribonucleic acid interference has the potential to change that with the targeting of essential viral genes via small interfering RNAs (siRNAs) offering the ability to directly and rapidly treat viral infections.
METHOD
The human lung carcinoma epithelial cell line, A549, was transfected with siRNAs targeting the N and P genes before infecting with hMPV A2 CAN97-83. Viral growth inhibition was then measured by the viral plaque assay and nucleoprotein (N) and phosphoprotein (P) gene knockdown was determined by real-time PCR.
RESULTS
In vitro prophylactic use of siRNAs targeting the 3'-abundantly expressed N and P genes of hMPV resulted in potent, sequence-specific viral inhibition. The viral inhibition was specific and not mediated by an anti-viral interferon-β response or cell death.
CONCLUSION
The findings presented here confirmed the highly potent, sequence-specific antiviral effect of siRNAs targeting the N and P gene of hMPV. These results may facilitate the development of a novel therapeutic agent for hMPV control.
Topics: A549 Cells; Gene Knockdown Techniques; Genes, Viral; Humans; Metapneumovirus; Nucleoproteins; Phosphoproteins; RNA Interference; RNA, Small Interfering; RNA, Viral; Transfection; Viral Proteins
PubMed: 30145592
DOI: 10.1159/000491927 -
Frontiers in Immunology 2022Maternal thyroid hormones (THs) are essential for the appropriate development of the fetus and especially for the brain. Recently, some studies have shown that THs...
Female offspring gestated in hypothyroxinemia and infected with human Metapneumovirus (hMPV) suffer a more severe infection and have a higher number of activated CD8 T lymphocytes.
Maternal thyroid hormones (THs) are essential for the appropriate development of the fetus and especially for the brain. Recently, some studies have shown that THs deficiency can also alter the immune system development of the progeny and their ability to mount an appropriate response against infectious agents. In this study, we evaluated whether adult mice gestated under hypothyroxinemia (Hpx) showed an altered immune response against infection with human metapneumovirus (hMPV). We observed that female mice gestated under Hpx showed higher clinical scores after seven days of hMPV infection. Besides, males gestated under Hpx have higher lung viral loads at day seven post-infection. Furthermore, the female offspring gestated in Hpx have already reduced the viral load at day seven and accordingly showed an increased proportion of activated (CD71 and FasL) CD8 T cells in the lungs, which correlated with a trend for a higher histopathological clinical score. These results support that T deficiency during gestation might condition the offspring differently in males and females, enhancing their ability to respond to hMPV.
Topics: Animals; CD8-Positive T-Lymphocytes; Female; Humans; Lung; Lymphocyte Count; Male; Metapneumovirus; Mice; Paramyxoviridae Infections
PubMed: 36159799
DOI: 10.3389/fimmu.2022.966917 -
Poultry Science Jan 2023Avian metapneumovirus (aMPV) is an important causative agent that causes acute respiratory disease and egg-dropping in chickens and turkeys. Here, we characterized an...
Avian metapneumovirus (aMPV) is an important causative agent that causes acute respiratory disease and egg-dropping in chickens and turkeys. Here, we characterized an aMPV subgroup C (aMPV/C) from 320-day-old broiler breeder chickens with severe respiratory diseases in Beijing, China, as evidenced by RT-PCR typing and confirmation of the nucleoprotein (N) gene sequence. The N gene sequence of the aMPV/C strain (designated BJ17) exhibited no deletions or insertions and possessed 94.6% to 99.6% identity to those of published aMPV/C isolates. The phylogenetic tree of the nucleotide sequences constructed using the neighbor-joining clustering method showed that the BJ17 strain formed one cluster with other aMPV/C viruses and formed one subcluster with published Chinese aMPV/C isolates regardless of Muscovy duck or chicken origins. Comparative analysis of the N proteins showed that a unique amino acid residue D at position 110 might be associated with regional distribution due to its occurrence in all the Chinese aMPV/C isolates only. Strain BJ17 was successfully isolated by cultured Vero cell passage and further inoculated in 3-wk-old specific-pathogen-free chickens for the examination of pathogenicity. Animal experimental results showed that BJ17-inoculated chickens had severe respiratory diseases and inflammatory lesions, as demonstrated by pathological changes and aMPV antigen in the nasal turbinate, tracheae, and lung tissues. These results enrich the available information regarding the epidemiology and pathogenicity of aMPV/C in chickens, which may facilitate the development of effective measures against aMPV/C infection in China.
Topics: Animals; Metapneumovirus; Chickens; Paramyxoviridae Infections; Beijing; Phylogeny; China; Antibodies, Viral; Turkeys; Poultry Diseases
PubMed: 36435163
DOI: 10.1016/j.psj.2022.102250 -
Clinics in Laboratory Medicine Dec 2009Viruses are major contributors to morbidity and mortality from acute respiratory infections in all age groups worldwide. Accurate identification of the etiologic agent... (Review)
Review
Viruses are major contributors to morbidity and mortality from acute respiratory infections in all age groups worldwide. Accurate identification of the etiologic agent of respiratory tract infections is important for proper patient management. Diagnosis can be problematic, because a range of potential pathogens can cause similar clinical symptoms. Nucleic acid amplification testing is emerging as the preferred method of diagnostic testing. Real-time technology and the ability to perform multiplex testing have facilitated this emergence. Commercial platforms for nucleic acid amplification testing of respiratory viruses include real-time polymerase chain reaction (PCR), nucleic acid sequence-based amplification, and loop-mediated isothermal amplification. Multiplex PCR with fluidic microarrays or DNA chips are the most recent diagnostic advance. These assays offer significant advantages in sensitivity over antigen detection methods and in most cases also over traditional culture methods. A limited number of assays, however, are commercially available, thus laboratory developed assays frequently are used. This article reviews the performance of commercially available assays and discusses issues relevant to the development of in-house assays.
Topics: Adenoviridae; DNA, Viral; Humans; Metapneumovirus; Nucleic Acid Amplification Techniques; Orthomyxoviridae; RNA, Viral; Respiratory Syncytial Virus, Human; Respiratory Tract Infections; Respirovirus
PubMed: 19892227
DOI: 10.1016/j.cll.2009.07.008 -
MBio Jan 2024Human metapneumovirus (hMPV) is an important respiratory pathogen for which no licensed antivirals or vaccines exist. Single-domain antibodies represent promising...
Human metapneumovirus (hMPV) is an important respiratory pathogen for which no licensed antivirals or vaccines exist. Single-domain antibodies represent promising antiviral biologics that can be easily produced and formatted. We describe the isolation and detailed characterization of two hMPV-neutralizing single-domain antibodies that are directed against the fusion protein F. One of these single-domain antibodies broadly neutralizes hMPV A and B strains, can prevent proteolytic maturation of F, and binds to an epitope in the F trimer interface. This suggests that hMPV pre-F undergoes trimer opening or "breathing" on infectious virions, exposing a vulnerable site for neutralizing antibodies. Finally, we show that this single-domain antibody, fused to a human IgG1 Fc, can protect cotton rats against hMPV replication, an important finding for potential future clinical applications.
Topics: Humans; Metapneumovirus; Single-Domain Antibodies; Antibodies, Viral; Antibodies, Neutralizing; Epitopes; Viral Fusion Proteins
PubMed: 38117059
DOI: 10.1128/mbio.02122-23 -
Journal of Virological Methods Oct 2012The genus Metapneumovirus within the subfamily Pneumovirinae and family Paramyxoviridae includes only two viruses, human metapneumovirus (hMPV) and avian metapneumovirus...
The genus Metapneumovirus within the subfamily Pneumovirinae and family Paramyxoviridae includes only two viruses, human metapneumovirus (hMPV) and avian metapneumovirus (aMPV), which cause respiratory disease in humans and birds, respectively. These two viruses grow poorly in cell culture and other quantitation methods, such as indirect immuno-staining and immuno-fluorescent assays, are expensive, time consuming, and do not allow for plaque purification of the virus. In order to enhance research efforts for studying these two viruses, a direct plaque assay for both hMPV and aMPV has been developed. By optimizing the chemical components of the agarose overlay, it was found that both hMPV with a trypsin-independent F cleavage site and aMPV formed clear and countable plaques in a number of mammalian cell lines (such as Vero-E6 and LLC-MK2 cells) after 5 days of incubation. The plaque forming assay has similar sensitivity and reliability as the currently used immunological methods for viral quantitation. The plaque assay is also a more simple, rapid, and economical method compared to immunological assays, and in addition allows for plaque purification of the viruses. The direct plaque assay will be a valuable method for the quantitation and evaluation of the biological properties of some metapneumoviruses.
Topics: Animals; Cell Line; Culture Media; Humans; Metapneumovirus; Sensitivity and Specificity; Time Factors; Viral Plaque Assay; Virus Cultivation
PubMed: 22684013
DOI: 10.1016/j.jviromet.2012.05.030 -
PloS One 2019Human metapneumovirus (HMPV) has been a notable etiological agent of acute respiratory infection in humans, but it was not discovered until 2001, because HMPV replicates...
Human metapneumovirus (HMPV) has been a notable etiological agent of acute respiratory infection in humans, but it was not discovered until 2001, because HMPV replicates only in a limited number of cell lines and the cytopathic effect (CPE) is often mild. To promote the study of HMPV, several groups have generated green fluorescent protein (GFP)-expressing recombinant HMPV strains (HMPVGFP). However, the growing evidence has complicated the understanding of cell line specificity of HMPV, because it seems to vary notably among HMPV strains. In addition, unique A2b clade HMPV strains with a 180-nucleotide duplication in the G gene (HMPV A2b180nt-dup strains) have recently been detected. In this study, we re-evaluated and compared the cell line specificity of clinical isolates of HMPV strains, including the novel HMPV A2b180nt-dup strains, and six recombinant HMPVGFP strains, including the newly generated recombinant HMPV A2b180nt-dup strain, MG0256-EGFP. Our data demonstrate that VeroE6 and LLC-MK2 cells generally showed the highest infectivity with any clinical isolates and recombinant HMPVGFP strains. Other human-derived cell lines (BEAS-2B, A549, HEK293, MNT-1, and HeLa cells) showed certain levels of infectivity with HMPV, but these were significantly lower than those of VeroE6 and LLC-MK2 cells. Also, the infectivity in these suboptimal cell lines varied greatly among HMPV strains. The variations were not directly related to HMPV genotypes, cell lines used for isolation and propagation, specific genome mutations, or nucleotide duplications in the G gene. Thus, these variations in suboptimal cell lines are likely intrinsic to particular HMPV strains.
Topics: A549 Cells; Cell Line; Cytopathogenic Effect, Viral; Green Fluorescent Proteins; HEK293 Cells; HeLa Cells; Humans; Metapneumovirus; Respiratory Tract Infections
PubMed: 31013314
DOI: 10.1371/journal.pone.0215822 -
Clinical Infectious Diseases : An... Jun 2020Human metapneumovirus (hMPV) commonly causes upper and lower respiratory tract infections. Here, we performed long-term retrospective surveillance of hMPV infection...
Clinical Features, Epidemiology, and Climatic Impact of Genotype-specific Human Metapneumovirus Infections: Long-term Surveillance of Hospitalized Patients in South Korea.
BACKGROUND
Human metapneumovirus (hMPV) commonly causes upper and lower respiratory tract infections. Here, we performed long-term retrospective surveillance of hMPV infection among patients hospitalized in South Korea between 2007 and 2016 and investigated seasonal dynamics and clinical characteristics associated with each virus subtype/genotype.
METHODS
Patient specimens were tested for hMPV and other respiratory viruses by commercial molecular assays. Medical records of hMPV-positive patients were reviewed, and hMPV subtype/genotype analysis was performed. We also collected meteorological data and analyzed relationships with hMPV activity.
RESULTS
Of 23 694 specimens, 1275 (5.4%) were positive; among them, 94.0% were classified into 5 subtypes (A1, A2a, A2b, B1, and B2). Some clinical manifestations differed according to hMPV genotype; however, there was no correlation between hMPV subtype and clinical outcome. Viral activity peaked at 13-20 weeks (April and May) and was associated with climate-specific factors, including temperature, relative humidity, diurnal temperature variation, wind speed, and sunshine duration.
CONCLUSIONS
This large-scale, 10-year study provides valuable information about the clinical characteristics associated with hMPV subtypes and climate factors contributing to virus transmission.
Topics: Genotype; Humans; Infant; Metapneumovirus; Paramyxoviridae Infections; Republic of Korea; Respiratory Tract Infections; Retrospective Studies
PubMed: 31353397
DOI: 10.1093/cid/ciz697 -
Journal of Microbiology and... Dec 2019The isolation of respiratory viruses, especially from clinical specimens, often shows poor efficiency with classical cell culture methods. The lack of suitable methods...
The isolation of respiratory viruses, especially from clinical specimens, often shows poor efficiency with classical cell culture methods. The lack of suitable methods to generate virus particles inhibits the development of diagnostic assays, treatments, and vaccines. We compared three inoculation methods, classical cell culture, the addition of a JAK2 inhibitor AZD1480, and centrifugation-enhanced inoculation (CEI), to replicate human respiratory syncytial virus (HRSV) and human metapneumovirus (HMPV). In addition, a combined method using AZD1480 treatment and CEI was used on throat swabs to verify that this method could increase virus isolation efficiency from human clinical specimens. Both CEI and AZD1480 treatment increased HRSV and HMPV genome replication. Also, the combined method using CEI and AZD1480 treatment enhanced virus proliferation synergistically. The combined method is particularly suited for the isolation of interferon-sensitive or slowly growing viruses from human clinical specimens.
Topics: Centrifugation; Humans; Metapneumovirus; Pneumovirus; Pyrazoles; Pyrimidines; Respiratory Syncytial Virus, Human; Specimen Handling; Virus Cultivation; Virus Replication
PubMed: 31581384
DOI: 10.4014/jmb.1906.06050 -
Scientific Reports Mar 2021It is uncertain whether clinical severity of an infection varies by pathogen or by multiple infections. Using hospital-based surveillance in children, we investigate the...
It is uncertain whether clinical severity of an infection varies by pathogen or by multiple infections. Using hospital-based surveillance in children, we investigate the range of clinical severity for patients singly, multiply, and not infected with a group of commonly circulating viruses in Nha Trang, Vietnam. RT-PCR was performed to detect 13 respiratory viruses in nasopharyngeal samples from enrolled patients. We apply a novel clinical severity score and examine associations with the odds of being severe and differences in raw severity scores. We find no difference in severity between 0-, 1-, and 2-concurrent infections and little differences in severity between specific viruses. We find RSV and HMPV infections to be associated with 2- and 1.5-fold increase in odds of being severe, respectively, and that infection with ADV is consistently associated with lower risk of severity. Clinically, based on the results here, if RSV or HMPV virus is suspected, PCR testing for confirmatory diagnosis and for detection of multiple coinfecting viruses would be fruitful to assess whether a patient's disease course is going to be severe.
Topics: Alphaherpesvirinae; Child; Child, Hospitalized; Child, Preschool; Coinfection; Female; Humans; Infant; Infant, Newborn; Male; Metapneumovirus; Nasopharynx; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Human; Respiratory Tract Infections; Vietnam; Virus Diseases
PubMed: 33664311
DOI: 10.1038/s41598-021-84423-2