scholarly journals Chimeric Influenza A Viruses with a Functional Influenza B Virus Neuraminidase or Hemagglutinin

2003 ◽  
Vol 77 (17) ◽  
pp. 9116-9123 ◽  
Author(s):  
Astrid Flandorfer ◽  
Adolfo García-Sastre ◽  
Christopher F. Basler ◽  
Peter Palese
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Mdck Cells ◽  
Cytoplasmic Tail ◽  
Type A ◽  
Influenza B Virus ◽  
Influenza B ◽  
Type B ◽  
Wild Type ◽  
B Virus

ABSTRACT Reassortment of influenza A and B viruses has never been observed in vivo or in vitro. Using reverse genetics techniques, we generated recombinant influenza A/WSN/33 (WSN) viruses carrying the neuraminidase (NA) of influenza B virus. Chimeric viruses expressing the full-length influenza B/Yamagata/16/88 virus NA grew to titers similar to that of wild-type influenza WSN virus. Recombinant viruses in which the cytoplasmic tail or the cytoplasmic tail and the transmembrane domain of the type B NA were replaced with those of the type A NA were impaired in tissue culture. This finding correlates with reduced NA content in virions. We also generated a recombinant influenza A virus expressing a chimeric hemagglutinin (HA) protein in which the ectodomain is derived from type B/Yamagata/16/88 virus HA, whereas both the cytoplasmic and the transmembrane domains are derived from type A/WSN virus HA. This A/B chimeric HA virus did not grow efficiently in MDCK cells. However, after serial passage we obtained a virus population that grew to titers as high as wild-type influenza A virus in MDCK cells. One amino acid change in position 545 (H545Y) was found to be responsible for the enhanced growth characteristics of the passaged virus. Taken together, we show here that the absence of reassortment between influenza viruses belonging to different A and B types is not due to spike glycoprotein incompatibility at the level of the full-length NA or of the HA ectodomain.

scholarly journals Clinical Investigations. Comparison of Directigen Flu A+B with Real Time PCR in the Diagnosis of Influenza / Сравнение Иммунохроматографического Метода (Directigen Flu A+B) И Теста RT-PCR При Инфекциях Гриппа

Folia Medica ◽  
2015 ◽  
Vol 57 (2) ◽  
pp. 104-110 ◽  
Author(s):  
Golubinka Bosevska ◽  
Nikola Panovski ◽  
Elizabeta Janceska ◽  
Vladimir Mikik ◽  
Irena Kondova Topuzovska ◽  
...  
Keyword(s):  
Real Time ◽  
Influenza A Virus ◽  
Real Time Pcr ◽  
Influenza A ◽  
Age Groups ◽  
Influenza Viruses ◽  
Influenza B Virus ◽  
Influenza B ◽  
B Virus ◽  
Nose And Throat

AbstractEarly diagnosis and treatment of patients with influenza is the reason why physicians need rapid high-sensitivity influenza diagnostic tests that require no complex lab equipment and can be performed and interpreted within 15 min. The Aim of this study was to compare the rapid Directigen Flu A+B test with real time PCR for detection of influenza viruses in the Republic of Macedonia. MATERIALS AND METHODS: One-hundred-eight respiratory samples (combined nose and throat swabs) were routinely collected for detection of influenza virus during influenza seasons. Forty-one patients were pediatric cases and 59 were adult. Their mean age was 23 years. The patients were allocated into 6 age groups: 0 - 4 yrs, 5 - 9 yrs, 10 - 14 yrs, 15 - 19 yrs, 20-64 yrs and > 65 yrs. Each sample was tested with Directigen Flu A+B and CDC real time PCR kit for detection and typisation/subtypisation of influenza according to the lab diagnostic protocol. RESULTS: Directigen Flu A+B identified influenza A virus in 20 (18.5%) samples and influenza B virus in two 2 (1.9%) samples. The high specificity (100%) and PPV of Directigen Flu A+B we found in our study shows that the positive results do not need to be confirmed. The overall sensitivity of Directigen Flu A+B is 35.1% for influenza A virus and 33.0% for influenza B virus. The sensitivity for influenza A is higher among children hospitalized (45.0%) and outpatients (40.0%) versus adults. CONCLUSION: Directigen Flu A+B has relatively low sensitivity for detection of influenza viruses in combined nose and throat swabs. Negative results must be confirmed.

scholarly journals STUDIES ON THE MECHANISM OF ADAPTATION OF INFLUENZA VIRUS TO MICE

1947 ◽  
Vol 86 (5) ◽  
pp. 357-366 ◽  
Author(s):  
George K. Hirst
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
High Titer ◽  
Strain Difference ◽  
Mouse Lung ◽  
Influenza B Virus ◽  
Influenza B ◽  
Difference Problem ◽  
B Virus ◽  
Repeated Passage

1. When strains of influenza A virus which have been isolated in chick embryos are introduced into the mouse lung, the virus multiplies readily and achieves initially a titer which is as high as is even obtained, even after repeated passage. The high initial titer of virus may be unaccompanied by any lethal or visible pathogenic effects; but with four or five mouse passages the agent becomes lethal in high titer and causes extensive pulmonary consolidation, though its capacity to multiply in the lung has not increased. In one example the adaptation to mouse lung was accompanied by increasing capacity to agglutinate guinea pig red cells without a corresponding increase in agglutinating power for chicken cells. Influenza B virus, in preliminary tests, did not behave in a similar fashion. 2. The adaptation of influenza A virus to mice is accompanied by changes in antigenic pattern, as detected by cross-tests with the agglutination inhibition method. Two strains, initially similar, with passage, changed in pattern along divergent paths so that they became not only unlike the parent strains but unlike each other. This finding has important implications for the interpretation of the strain difference problem in human influenza.

scholarly journals Incoming Influenza A Virus Evades Early Host Recognition, while Influenza B Virus Induces Interferon Expression Directly upon Entry

2012 ◽  
Vol 86 (20) ◽  
pp. 11183-11193 ◽  
Author(s):  
P. Osterlund ◽  
M. Strengell ◽  
L. P. Sarin ◽  
M. M. Poranen ◽  
R. Fagerlund ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Host Recognition ◽  
Influenza B Virus ◽  
Influenza B ◽  
B Virus

Influenza B Virus Causes Milder Pathogenesis and Weaker Inflammatory Responses in Ferrets Than Influenza A Virus

2009 ◽  
Vol 22 (6) ◽  
pp. 423-430 ◽  
Author(s):  
Yun Hee Kim ◽  
Hyun Soo Kim ◽  
Sung Hwan Cho ◽  
Sang Heui Seo
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Inflammatory Responses ◽  
Influenza B Virus ◽  
Influenza B ◽  
B Virus

scholarly journals The N-Terminal Extension of the Influenza B Virus Nucleoprotein Is Not Required for Nuclear Accumulation or the Expression and Replication of a Model RNA

1998 ◽  
Vol 72 (6) ◽  
pp. 5307-5312 ◽  
Author(s):  
Mark P. Stevens ◽  
Wendy S. Barclay
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Viral Rna ◽  
Nuclear Accumulation ◽  
Influenza B Virus ◽  
Virus Protein ◽  
Influenza B ◽  
Coding Region ◽  
B Virus ◽  
N Terminus

ABSTRACT The nucleoprotein (NP) of influenza B virus is 50 amino acids longer at the N-terminus than influenza A virus NP and lacks homology to the A virus protein over the first 69 residues. We have deleted the N-terminal 51 and 69 residues of the influenza B/Ann Arbor/1/66 virus NP and show that nuclear accumulation of the protein is unaffected. This indicates that the nuclear localization signal is not located at the extreme N terminus, as in influenza A virus NP. To determine if the N-terminal mutants could support the expression and replication of a model influenza B virus RNA, the genes encoding the subunits of the viral RNA-dependent RNA polymerase (PA, PB1, and PB2) were cloned. Coexpression of NP and the P proteins in 293 cells was found to permit the expression and replication of a transfected model RNA based on segment 4 of B/Maryland/59, in which the hemagglutinin-coding region was replaced by a chloramphenicol acetyltransferase gene. The expression and replication of the synthetic RNA were not affected by the replacement of NP with NP mutants lacking the N-terminal 51 or 69 residues, indicating that the N-terminal extension is not required for transcription or replication of the viral RNA. In addition, we report that the influenza B virus NP cannot be functionally replaced by type A virus NP in this system.

scholarly journals Influenza B viruses exhibit lower within-host diversity than influenza A viruses in human hosts

2019 ◽  
Author(s):  
Andrew L. Valesano ◽  
William J. Fitzsimmons ◽  
John T. McCrone ◽  
Joshua G. Petrie ◽  
Arnold S. Monto ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Influenza A Virus ◽  
Influenza A ◽  
Evolutionary Dynamics ◽  
Influenza Viruses ◽  
Influenza B Virus ◽  
Influenza B ◽  
Influenza A Viruses ◽  
Community Based ◽  
B Virus

AbstractInfluenza B virus undergoes seasonal antigenic drift more slowly than influenza A, but the reasons for this difference are unclear. While the evolutionary dynamics of influenza viruses play out globally, they are fundamentally driven by mutation, reassortment, drift, and selection within individual hosts. These processes have recently been described for influenza A virus, but little is known about the evolutionary dynamics of influenza B virus (IBV) at the level of individual infections and transmission events. Here we define the within-host evolutionary dynamics of influenza B virus by sequencing virus populations from naturally-infected individuals enrolled in a prospective, community-based cohort over 8176 person-seasons of observation. Through analysis of high depth-of-coverage sequencing data from samples from 91 individuals with influenza B, we find that influenza B virus accumulates lower genetic diversity than previously observed for influenza A virus during acute infections. Consistent with studies of influenza A viruses, the within-host evolution of influenza B viruses is characterized by purifying selection and the general absence of widespread positive selection of within-host variants. Analysis of shared genetic diversity across 15 sequence-validated transmission pairs suggests that IBV experiences a tight transmission bottleneck similar to that of influenza A virus. These patterns of local-scale evolution are consistent with influenza B virus’ slower global evolutionary rate.ImportanceThe evolution of influenza virus is a significant public health problem and necessitates the annual evaluation of influenza vaccine formulation to keep pace with viral escape from herd immunity. Influenza B virus is a serious health concern for children, in particular, yet remains understudied compared to influenza A virus. Influenza B virus evolves more slowly than influenza A, but the factors underlying this are not completely understood. We studied how the within-host diversity of influenza B virus relates to its global evolution by sequencing viruses from a community-based cohort. We found that influenza B virus populations have lower within-host genetic diversity than influenza A virus and experience a tight genetic bottleneck during transmission. Our work provides insights into the varying dynamics of influenza viruses in human infection.

Detection of some Microorganisms in Patients with Pericarditis by Immunofluresent Assay in Hilla City / Iraq

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Ilham A Bunyan ◽  
Shokry Faaz ◽  
Hala H Ali
Keyword(s):  
Pericardial Effusion ◽  
Influenza A Virus ◽  
Teaching Hospital ◽  
Influenza A ◽  
Culture Media ◽  
Hospitalized Patients ◽  
Influenza B Virus ◽  
Influenza B ◽  
Acute Pericarditis ◽  
B Virus

In this study, (17) pericardial effusion specimens and blood samples were obtained from hospitalized patients diagnosedwith pericardial effusion at Marjan Teaching Hospital, AL-Sader Teaching Hospital and Ibn-AL-Biatar Cardiovascular Center with age range between (2-77) years old from both sexes, 6(35.30%) male and 11(64.70%) of them were female. The period of collection were extended from July (2018) to January (2019). A total of (17) samples from hospitalized patients with pericardial effusion were included in this study, only 9(52.9%) patients with positive bacterial blood culture media, 7(77.8%) from female and 2(22.2%) from male, and 10(58.8%) patients with positive bacterial pericardial effusion, 7(70%) female and 3(30%) male. In the positive culture group, from 10(58.8%) cases, death occurred in 2(20%) patients, and in the negative culture group, from 7(41.2%) cases, death occurred in 2(38.5%) patients. The sera and pericardium effusion of patients in showed anti-IgM to M. pneumoniae, M. pneumophilia, L. pneumophilia, C. pneumophilia, RSV, Adenovirus, Influenza A virus, and Influenza B virus antibodies. The results showed 7/17(41.2%) positive cases of pericarditis attributed to M. pneumoniae. In (17) patients with acute pericarditis admitted found 2/17(11.8%) positive cases detected by IFA in patients with L. pneumophilia. IFA revealed that 1/17(5.9%) of positive cases for the assay positive for Chlamydophila pneumoniae. Recent study revealed that the IFA detect 2/17 (11.8%) of cases positive for Adenovirus. Depending on IFA recent study identified 2/17(11.8%) cases with RSV associated with another etiological agents and present a case of Influenza A virus infection 1/17(5.9%). Our results showed a case with pericardial effusion positive for Influenza B virus 1/17(5.9%) associated with presence of RSV and L. pneumophilia in patient with intestinal cancer with negative results of bacterial culture media for both pericardial effusion and blood.

scholarly journals Comparison of the performance of the rapid antigen detection actim Influenza A&B test and RT-PCR in different respiratory specimens

2009 ◽  
Vol 58 (3) ◽  
pp. 365-370 ◽  
Author(s):  
B. Ghebremedhin ◽  
I. Engelmann ◽  
W. König ◽  
B. König
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Antigen Detection ◽  
Influenza B Virus ◽  
Influenza B ◽  
Rt Pcr ◽  
Pcr Assay ◽  
B Virus ◽  
B Test ◽  
Respiratory Specimens

Nowadays, influenza antigen detection test kits are used most frequently to detect influenza A or B virus to establish the diagnosis of influenza rapidly and initiate appropriate therapy. This study was conducted to evaluate the performance of the actim Influenza A&B test (Medix Biochemica). Overall, 473 respiratory specimens were analysed in the actim Influenza A&B test and the results were compared with those from an RT-PCR assay; 461 of these samples originated from paediatric patients aged 7 weeks to 6.5 years either with influenza-related symptoms or from the intensive care unit, and 12 samples originated from adults with underlying lung or haematological diseases. Diagnosis of influenza A or B virus could be established using the actim Influenza A&B test (9/473 samples for influenza A virus and 6/473 for influenza B virus). RT-PCR revealed 23 patients with influenza virus (13/473 for influenza A virus and 10/473 for influenza B virus). The sensitivity and specificity of the actim Influenza A&B test were 65 and 100 % compared with the RT-PCR assay. However, 32 external quality assessment samples containing seven different strains of influenza A subtypes H1N1 and H3N2 and the avian H5N1 were detected correctly by the actim Influenza A&B test. No cross-reactivity to a range of bacterial, fungal and other viral pathogens was observed. In conclusion, the actim Influenza A&B test is reliable for positive results due to its high specificity. Nevertheless, negative results from this test need to be confirmed by a more sensitive assay because of the low sensitivity observed with diagnostic samples.

scholarly journals Broadly Cross-Reactive, Nonneutralizing Antibodies against Influenza B Virus Hemagglutinin Demonstrate Effector Function-Dependent Protection against Lethal Viral Challenge in Mice

2019 ◽  
Vol 93 (6) ◽  
Author(s):  
Guha Asthagiri Arunkumar ◽  
Andriani Ioannou ◽  
Teddy John Wohlbold ◽  
Philip Meade ◽  
Sadaf Aslam ◽  
...  
Keyword(s):  
Virus Infection ◽  
Influenza A Virus ◽  
Mechanism Of Action ◽  
Influenza A ◽  
Effector Function ◽  
Influenza B Virus ◽  
Influenza B ◽  
B Virus ◽  
Protective Antibodies

ABSTRACT Protection from influenza virus infection is canonically associated with antibodies that neutralize the virus by blocking the interaction between the viral hemagglutinin and host cell receptors. However, protection can also be conferred by other mechanisms, including antibody-mediated effector functions. Here, we report the characterization of 22 broadly cross-reactive, nonneutralizing antibodies specific for influenza B virus hemagglutinin. The majority of these antibodies recognized influenza B viruses isolated over the period of 73 years and bind the conserved stalk domain of the hemagglutinin. A proportion of the characterized antibodies protected mice from both morbidity and mortality after challenge with a lethal dose of influenza B virus. Activity in an antibody-dependent cell-mediated cytotoxicity reporter assay correlated strongly with protection, suggesting that Fc-dependent effector function determines protective efficacy. The information regarding mechanism of action and epitope location stemming from our characterization of these antibodies will inform the design of urgently needed vaccines that could induce broad protection against influenza B viruses. IMPORTANCE While broadly protective antibodies against the influenza A virus hemagglutinin have been well studied, very limited information is available for antibodies that broadly recognize influenza B viruses. Similarly, the development of a universal or broadly protective influenza B virus vaccine lags behind the development of such a vaccine for influenza A virus. More information about epitope location and mechanism of action of broadly protective influenza B virus antibodies is required to inform vaccine development. In addition, protective antibodies could be a useful tool to treat or prevent influenza B virus infection in pediatric cohorts or in a therapeutic setting in immunocompromised individuals in conjugation with existing treatment avenues.

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