scholarly journals A NS1-binding monoclonal antibody interacts with two residues that are highly conserved in seasonal as well as newly emerged influenza A virus

2019 ◽  
Vol 77 (1) ◽  
Author(s):  
Su Hui Catherine Teo ◽  
Jian-Ping Wu ◽  
Chee-Keng Mok ◽  
Yee-Joo Tan
Keyword(s):  
Monoclonal Antibody ◽  
Influenza A Virus ◽  
Influenza A ◽  
Rna Binding ◽  
Intracellular Localization ◽  
Cross Reactivity ◽  
Structural Protein ◽  
Multifunctional Protein ◽  
Good Target ◽  
Conformational Plasticity

Abstract The non-structural protein 1 (NS1) of influenza A virus (IAV) is a multifunctional protein that antagonizes host antiviral responses, modulating virus pathogenesis. As such, it serves as a good target for research and diagnostic assay development. In this study, we have generated a novel monoclonal antibody (mAb) 19H9 and epitope mapping revealed that two residues, P85 and Y89, of NS1 are essential for interacting with this mAb. Furthermore, residues P85 and Y89 are found to be highly conserved across different IAV subtypes, namely seasonal H1N1 and H3N2, as well as the highly pathogenic H5N1 and H5N6 avian strains. Indeed, mAb 19H9 exhibits broad cross-reactivity with IAV strains of different subtypes. The binding of mAb 19H9 to residue Y89 was further confirmed by the abrogation of interaction between NS1 and p85β. Additionally, mAb 19H9 also detected NS1 proteins expressed in IAV-infected cells, showing NS1 intracellular localization in the cytoplasm and nucleolus. To our knowledge, mAb 19H9 is the first murine mAb to bind at the juxtaposition between the N-terminal RNA-binding domain and C-terminal effector domain of NS1. It could serve as a useful research tool for studying the conformational plasticity and dynamic changes in NS1.

Influenza A virus non-structural protein 1 (NS1) interacts with cellular multifunctional protein nucleolin during infection

2007 ◽  
Vol 362 (4) ◽  
pp. 880-885 ◽  
Author(s):  
Rikinori Murayama ◽  
Yuichi Harada ◽  
Toshikatsu Shibata ◽  
Kazumichi Kuroda ◽  
Satoshi Hayakawa ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Structural Protein ◽  
Multifunctional Protein

scholarly journals Conformational plasticity of the influenza A virus NS1 protein

2014 ◽  
Vol 95 (10) ◽  
pp. 2099-2105 ◽  
Author(s):  
Benjamin G. Hale
Keyword(s):  
Influenza A Virus ◽  
Protein Function ◽  
Influenza A ◽  
Structural Basis ◽  
Ns1 Protein ◽  
Structural Protein ◽  
Diverse Range ◽  
Single Structure ◽  
Conformational Plasticity ◽  
Important Virulence Factor

During infection, the influenza A virus non-structural protein 1 (NS1) interacts with a diverse range of viral and cellular factors to antagonize host antiviral defences and promote viral replication. Here, I review the structural basis for some of these functions and discuss the emerging view that NS1 cannot simply be regarded as a ‘static’ protein with a single structure. Rather, the dynamic property of NS1 to adopt various quaternary conformations is critical for its multiple activities. Understanding NS1 plasticity, and the mechanisms governing this plasticity, will be essential for assessing both fundamental protein function and the consequences of strain-dependent polymorphisms in this important virulence factor.

scholarly journals Mutational Analysis of Influenza A Virus Nucleoprotein: Identification of Mutations That Affect RNA Replication

1999 ◽  
Vol 73 (2) ◽  
pp. 1186-1194 ◽  
Author(s):  
Ignacio Mena ◽  
Enrique Jambrina ◽  
Carmen Albo ◽  
Beatriz Perales ◽  
Juan Ortín ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rna Binding ◽  
Mutational Analysis ◽  
Intracellular Localization ◽  
Single Amino Acid ◽  
Temperature Sensitive ◽  
Virus Mutant

ABSTRACT The influenza A virus nucleoprotein (NP) is a multifunctional polypeptide which plays a pivotal role in virus replication. To get information on the domains and specific residues involved in the different NP activities, we describe here the preparation and characterization of 20 influenza A virus mutant NPs. The mutations, mostly single-amino-acid substitutions, were introduced in a cDNA copy of the A/Victoria/3/75 NP gene and, in most cases, affected residues located in regions that were highly conserved across the NPs of influenza A, B, and C viruses. The mutant NPs were characterized (i) in vivo (cell culture) by analyzing their intracellular localization and their functionality in replication, transcription, and expression of model RNA templates; and (ii) in vitro by analyzing their RNA-binding and sedimentation properties. The results obtained allowed us to identify both a mutant protein that accumulated in the cytoplasm and mutations that altered the functionality and/or the oligomerization state of the NP polypeptide. Among the mutations that reduced the NP capability to express chloramphenicol acetyltransferase protein from a model viral RNA (vRNA) template, some displayed a temperature-sensitive phenotype. Interestingly, four mutant NPs, which showed a reduced functionality in synthesizing cRNA molecules from a vRNA template, were fully competent to reconstitute complementary ribonucleoproteins (cRNPs) capable of synthesizing vRNAs, which in turn yielded mRNA molecules. Based on the phenotype of these mutants and on previously published observations, it is proposed that these mutant NPs have a reduced capability to interact with the polymerase complex and that this NP-polymerase interaction is responsible for making vRNPs switch from mRNA to cRNA synthesis.

The strong positive correlation between effective affinity and infectivity neutralization of highly cross-reactive monoclonal antibody IIB4, which recognizes antigenic site B on influenza A virus haemagglutinin

Microbiology ◽  
2000 ◽  
Vol 81 (7) ◽  
pp. 1727-1735 ◽  
Author(s):  
F. Kostolanský ◽  
E. Varečková ◽  
T. Betáková ◽  
V. Mucha ◽  
G. Russ ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Influenza A Virus ◽  
Influenza A ◽  
Antigenic Site ◽  
Fold Increase ◽  
Cross Reactivity ◽  
Influenza Viruses ◽  
Mass Action ◽  
Strong Positive Correlation ◽  
Positive Correlation

Monoclonal antibody (MAb) IIB4 displays a rare combination of virus neutralization (VN) activity and broad cross-reactivity with influenza A virus strains of the H3 subtype isolated in a period from 1973 to 1988. The epitope of this antibody has been identified as around HA1 residues 198, 199 and 201. Here we report that residues 155, 159, 188, 189 and 193 also influence the binding of this antibody. We have used this antibody to study the relationship between antibody affinity and VN activity. Using one MAb and a single epitope on the haemagglutinin (HA) of different influenza viruses we found a strong positive correlation between effective affinity and VN activity of MAb IIB4. A 10-fold increase in effective affinity corresponded to the 2000-fold increase in VN titre. It follows from the law of mass action that for an effective affinity K=9×108 l/mol, 50% VN was achieved at approx. 10% occupation of HA spikes with antibody. In contrast, for an effective affinity K=6×107 l/mol, to achieve 50% VN, occupation of up to 98% of HA spikes was required. An effective affinity about K=6×107 l/mol thus represents the limiting value for VN because a further decrease in the affinity cannot be compensated by a higher concentration of antibody.

A novel RNA-binding motif in influenza A virus non-structural protein 1

1997 ◽  
Vol 4 (11) ◽  
pp. 891-895 ◽  
Author(s):  
Chen-ya Chien ◽  
Roberto Tejero ◽  
Yuanpeng Huang ◽  
Diane E. Zimmerman ◽  
Carlos B. Ríos ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rna Binding ◽  
Binding Motif ◽  
Structural Protein

scholarly journals Generation and characterization of a new panel of broadly reactive anti-NS1 mAbs for detection of influenza A virus

2013 ◽  
Vol 94 (3) ◽  
pp. 593-605 ◽  
Author(s):  
Md Niaz Rahim ◽  
Mohammed Selman ◽  
Patricia J. Sauder ◽  
Nicole E. Forbes ◽  
William Stecho ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
A549 Cells ◽  
Structural Protein ◽  
Good Target ◽  
Ns3 Protein ◽  
And Function ◽  
Selective Reactivity ◽  
Darby Canine Kidney

Influenza A virus (IAV) non-structural protein 1 (NS1) has multiple functions, is essential for virus replication and may be a good target for IAV diagnosis. To generate broadly cross-reactive NS1-specific mAbs, mice were immunized with A/Hong Kong/1/1968 (H3N2) 6×His-tagged NS1 and hybridomas were screened with glutathione S-transferase-conjugated NS1 of A/Puerto Rico/8/1934 (H1N1). mAbs were isotyped and numerous IgG-type clones were characterized further. Most clones specifically recognized NS1 from various H1N1 and H3N2 IAV types by both immunoblot and immunofluorescence microscopy in mouse M1, canine Madin–Darby canine kidney and human A549 cells. mAb epitopes were mapped by overlapping peptides and selective reactivity to the newly described viral NS3 protein. These mAbs detected NS1 in both the cytoplasm and nucleus by immunostaining, and some detected NS1 as early as 5 h post-infection, suggesting their potential diagnostic use for tracking productive IAV replication and characterizing NS1 structure and function. It was also demonstrated that the newly identified NS3 protein is localized in the cytoplasm to high levels.

scholarly journals Development of Neuraminidase Subtype-Specific Reference Antisera by Recombinant Protein Expressed in Baculovirus

2012 ◽  
Vol 20 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Kyu-Jun Lee ◽  
Jun-Gu Choi ◽  
Hyun-Mi Kang ◽  
Kwang-Il Kim ◽  
Choi-Kyu Park ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Influenza A Virus ◽  
Diagnostic Tests ◽  
Influenza A ◽  
Recombinant Baculovirus ◽  
Cross Reactivity ◽  
Specific Reference ◽  
Simple Method ◽  
Avian Influenza A Virus

ABSTRACTOutbreaks of avian influenza A virus infection, particularly the H5N1 strains that have affected birds and some humans for the past 15 years, have highlighted the need for increased surveillance and disease control. Such measures require diagnostic tests to detect and characterize the different subtypes of influenza virus. In the current study, a simple method for producing reference avian influenza virus antisera to be used in diagnostic tests was developed. Antisera of nine avian influenza A virus neuraminidases (NA) used for NA subtyping were produced using a recombinant baculovirus. The recombinant NA (rNA) proteins were expressed in Sf9 insect cells and inoculated intramuscularly into specific-pathogen-free chickens with the ISA70 adjuvant. The NA inhibition antibody titers of the rNA antiserum were in the ranges of 5 to 8 and 6 to 9 log2units after the primary and boost immunizations, respectively. The antisera were subtype specific, showing low cross-reactivity against every other NA subtype using the conventional thiobarbituric acid NA inhibition assay. These results suggest that this simple method for producing reference NA antisera without purification may be useful for the diagnosis and surveillance of influenza virus.

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