scholarly journals Subclade 2.2.1-Specific Human Monoclonal Antibodies That Recognize an Epitope in Antigenic Site A of Influenza A(H5) Virus HA Detected between 2015 and 2018

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 321
Author(s):  
Moe Okuda ◽  
Seiya Yamayoshi ◽  
Ryuta Uraki ◽  
Mutsumi Ito ◽  
Taiki Hamabata ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Influenza A ◽  
Antigenic Site ◽  
Influenza Viruses ◽  
Interspecies Transmission ◽  
Single Amino Acid ◽  
Human Monoclonal Antibodies ◽  
Highly Pathogenic ◽  
H5n1 Vaccine

Highly pathogenic avian H5 influenza viruses persist among poultry and wild birds throughout the world. They sometimes cause interspecies transmission between avian and mammalian hosts. H5 viruses possessing the HA of subclade 2.3.4.4, 2.3.2.1, 2.2.1, or 7.2 were detected between 2015 and 2018. To understand the neutralizing epitopes of H5-HA, we characterized 15 human monoclonal antibodies (mAbs) against the HA of H5 viruses, which were obtained from volunteers who received the H5N1 vaccine that contains a subclade 2.2.1 or 2.1.3.2 virus as an antigen. Twelve mAbs were specific for the HA of subclade 2.2.1, two mAbs were specific for the HA of subclade 2.1.3.2, and one mAb was specific for the HA of both. Of the 15 mAbs analyzed, nine, which were specific for the HA of subclade 2.2.1, and shared the VH and VL genes, possessed hemagglutination inhibition and neutralizing activities, whereas the others did not. A single amino acid substitution or insertion at positions 144–147 in antigenic site A conferred resistance against these nine mAbs to the subclade 2.2.1 viruses. The amino acids at positions 144–147 are highly conserved among subclade 2.2.1, but differ from those of other subclades. These results show that the neutralizing epitope including amino acids at positions 144–147 is targeted by human antibodies, and plays a role in the antigenic difference between subclade 2.2.1 and other subclades.

scholarly journals Broadly Reactive Human Monoclonal Antibodies Elicited following Pandemic H1N1 Influenza Virus Exposure Protect Mice against Highly Pathogenic H5N1 Challenge

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Raffael Nachbagauer ◽  
David Shore ◽  
Hua Yang ◽  
Scott K. Johnson ◽  
Jon D. Gabbard ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Monoclonal Antibodies ◽  
Influenza Viruses ◽  
Health Concern ◽  
Human Monoclonal Antibodies ◽  
Lethal Challenge ◽  
Highly Pathogenic ◽  
Zoonotic Infections ◽  
Stalk Domain ◽  
Group 1

ABSTRACT Broadly cross-reactive antibodies (Abs) that recognize conserved epitopes within the influenza virus hemagglutinin (HA) stalk domain are of particular interest for their potential use as therapeutic and prophylactic agents against multiple influenza virus subtypes, including zoonotic virus strains. Here, we characterized four human HA stalk-reactive monoclonal antibodies (MAbs) for their binding breadth and affinity, in vitro neutralization capacity, and in vivo protective potential against an highly pathogenic avian influenza virus. The monoclonal antibodies were isolated from individuals shortly following infection with (70-1F02 and 1009-3B05) or vaccination against (05-2G02 and 09-3A01) A(H1N1)pdm09. Three of the MAbs bound HAs from multiple strains of group 1 viruses, and one MAb, 05-2G02, bound to both group 1 and group 2 influenza A virus HAs. All four antibodies prophylactically protected mice against a lethal challenge with the highly pathogenic A/Vietnam/1203/04 (H5N1) strain. Two MAbs, 70-1F02 and 09-3A01, were further tested for their therapeutic efficacy against the same strain and showed good efficacy in this setting as well. One MAb, 70-1F02, cocrystallized with H5 HA and showed heavy-chain-only interactions similar to those seen with the previously described CR6261 anti-stalk antibody. Finally, we show that antibodies that compete with these MAbs are prevalent in serum from an individual recently infected with the A(H1N1)pdm09 virus. The antibodies described here can be developed into broad-spectrum antiviral therapeutics that could be used to combat infections by zoonotic or emerging pandemic influenza viruses. IMPORTANCE The rise in zoonotic infections of humans by emerging influenza viruses is a worldwide public health concern. The majority of recent zoonotic human influenza cases were caused by H7N9 and H5Nx viruses and were associated with high morbidity and mortality. In addition, seasonal influenza viruses are estimated to cause up to 650,000 deaths annually worldwide. Currently available antiviral treatment options include only neuraminidase inhibitors, but some influenza viruses are naturally resistant to these drugs, and others quickly develop resistance-conferring mutations. Alternative therapeutics are urgently needed. Broadly protective antibodies that target the conserved “stalk” domain of the hemagglutinin represent potential potent antiviral prophylactic and therapeutic agents that can assist pandemic preparedness. Here, we describe four human monoclonal antibodies that target conserved regions of influenza HA and characterize their binding spectrum as well as their protective capacity in prophylactic and therapeutic settings against a lethal challenge with a zoonotic influenza virus.

scholarly journals Amino Acids in Hemagglutinin Antigenic Site B Determine Antigenic and Receptor Binding Differences between A(H3N2)v and Ancestral Seasonal H3N2 Influenza Viruses

2016 ◽  
Vol 91 (2) ◽  
Author(s):  
Xiaoquan Wang ◽  
Natalia A. Ilyushina ◽  
Vladimir Y. Lugovtsev ◽  
Nicolai V. Bovin ◽  
Laura K. Couzens ◽  
...  
Keyword(s):  
United States ◽  
Amino Acids ◽  
Amino Acid ◽  
Influenza A ◽  
Antigenic Site ◽  
The United States ◽  
Influenza Viruses ◽  
Antigenic Difference ◽  
Antigenic Phenotype ◽  
Human Infections

ABSTRACT Influenza A H3N2 variant [A(H3N2)v] viruses, which have caused human infections in the United States in recent years, originated from human seasonal H3N2 viruses that were introduced into North American swine in the mid-1990s, but they are antigenically distinct from both the ancestral and current circulating H3N2 strains. A reference A(H3N2)v virus, A/Minnesota/11/2010 (MN/10), and a seasonal H3N2 strain, A/Beijing/32/1992 (BJ/92), were chosen to determine the molecular basis for the antigenic difference between A(H3N2)v and the ancestral viruses. Viruses containing wild-type and mutant MN/10 or BJ/92 hemagglutinins (HAs) were constructed and probed for reactivity with ferret antisera against MN/10 and BJ/92 in hemagglutination inhibition assays. Among the amino acids that differ between the MN/10 and BJ/92 HAs, those in antigenic site A had little impact on the antigenic phenotype. Within antigenic site B, mutations at residues 156, 158, 189, and 193 of MN/10 HA to those in BJ/92 switched the MN/10 antigenic phenotype to that of BJ/92. Mutations at residues 156, 157, 158, 189, and 193 of BJ/92 HA to amino acids present in MN/10 were necessary for BJ/92 to become antigenically similar to MN/10. The HA amino acid substitutions responsible for switching the antigenic phenotype also impacted HA binding to sialyl receptors that are usually present in the human respiratory tract. Our study demonstrates that antigenic site B residues play a critical role in determining both the unique antigenic phenotype and receptor specificity of A(H3N2)v viruses, a finding that may facilitate future surveillance and risk assessment of novel influenza viruses. IMPORTANCE Influenza A H3N2 variant [A(H3N2)v] viruses have caused hundreds of human infections in multiple states in the United States since 2009. Most cases have been children who had contact with swine in agricultural fairs. These viruses originated from human seasonal H3N2 viruses that were introduced into the U.S. swine population in the mid-1990s, but they are different from both these ancestral viruses and current circulating human seasonal H3N2 strains in terms of their antigenic characteristics as measured by hemagglutination inhibition (HI) assay. In this study, we identified amino acids in antigenic site B of the surface glycoprotein hemagglutinin (HA) that explain the antigenic difference between A(H3N2)v and the ancestral H3N2 strains. These amino acid mutations also alter binding to minor human-type glycans, suggesting that host adaptation may contribute to the selection of antigenically distinct H3N2 variants which pose a threat to public health.

scholarly journals Naturally Occurring Human Monoclonal Antibodies Neutralize both 1918 and 2009 Pandemic Influenza A (H1N1) Viruses

2009 ◽  
Vol 84 (6) ◽  
pp. 3127-3130 ◽  
Author(s):  
Jens C. Krause ◽  
Terrence M. Tumpey ◽  
Chelsey J. Huffman ◽  
Patricia A. McGraw ◽  
Melissa B. Pearce ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Pandemic Influenza ◽  
Influenza A ◽  
Antigenic Site ◽  
Human Monoclonal Antibodies ◽  
Influenza A H1n1 ◽  
Protein Sequence Homology ◽  
Hemagglutinin Protein

ABSTRACT The 2009 pandemic influenza A (H1N1) virus exhibits hemagglutinin protein sequence homology with the 1918 pandemic influenza virus. We found that human monoclonal antibodies recognized the Sa antigenic site on the head domains of both 1918 and 2009 hemagglutinins, a site that is hypervariable due to immune selection. These antibodies exhibited high potency against the 2009 virus in vitro, and one exerted a marked therapeutic effect in vivo.

scholarly journals Characterization of an enhanced antigenic change in the pandemic 2009 H1N1 influenza virus haemagglutinin

2014 ◽  
Vol 95 (5) ◽  
pp. 1033-1042 ◽  
Author(s):  
Blanca García-Barreno ◽  
Teresa Delgado ◽  
Sonia Benito ◽  
Inmaculada Casas ◽  
Francisco Pozo ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Influenza A ◽  
Point Mutations ◽  
Antigenic Site ◽  
Single Amino Acid ◽  
Antigenic Structure ◽  
Human Antibody ◽  
2009 H1n1

Murine hybridomas producing neutralizing mAbs specific to the pandemic influenza virus A/California/07/2009 haemagglutinin (HA) were isolated. These antibodies recognized at least two different but overlapping new epitopes that were conserved in the HA of most Spanish pandemic isolates. However, one of these isolates (A/Extremadura/RR6530/2010) lacked reactivity with the mAbs and carried two unique mutations in the HA head (S88Y and K136N) that were required simultaneously to eliminate reactivity with the murine antibodies. This unusual requirement directly illustrates the phenomenon of enhanced antigenic change proposed previously for the accumulation of simultaneous amino acid substitutions at antigenic sites of the influenza A virus HA during virus evolution (Shih et al., Proc Natl Acad Sci USA, 104 , 6283–6288, 2007). The changes found in the A/Extremadura/RR6530/2010 HA were not found in escape mutants selected in vitro with one of the mAbs, which contained instead nearby single amino acid changes in the HA head. Thus, either single or double point mutations may similarly alter epitopes of the new antigenic site identified in this work in the 2009 H1N1 pandemic virus HA. Moreover, this site is relevant for the human antibody response, as shown by competition of mAbs and human post-infection sera for virus binding. The results are discussed in the context of the HA antigenic structure and challenges posed for identification of sequence changes with possible antigenic impact during virus surveillance.

scholarly journals Functional Analysis of PA Binding by Influenza A Virus PB1: Effects on Polymerase Activity and Viral Infectivity

2001 ◽  
Vol 75 (17) ◽  
pp. 8127-8136 ◽  
Author(s):  
Daniel R. Perez ◽  
Ruben O. Donis
Keyword(s):  
Amino Acids ◽  
Influenza Virus ◽  
Amino Acid ◽  
Viral Replication ◽  
Influenza A Virus ◽  
Influenza A ◽  
Amino Acid Sequences ◽  
Influenza Viruses ◽  
Virus Growth ◽  
Transcription And Replication

ABSTRACT Influenza A virus expresses three viral polymerase (P) subunits—PB1, PB2, and PA—all of which are essential for RNA and viral replication. The functions of P proteins in transcription and replication have been partially elucidated, yet some of these functions seem to be dependent on the formation of a heterotrimer for optimal viral RNA transcription and replication. Although it is conceivable that heterotrimer subunit interactions may allow a more efficient catalysis, direct evidence of their essentiality for viral replication is lacking. Biochemical studies addressing the molecular anatomy of the P complexes have revealed direct interactions between PB1 and PB2 as well as between PB1 and PA. Previous studies have shown that the N-terminal 48 amino acids of PB1, termed domain α, contain the residues required for binding PA. We report here the refined mapping of the amino acid sequences within this small region of PB1 that are indispensable for binding PA by deletion mutagenesis of PB1 in a two-hybrid assay. Subsequently, we used site-directed mutagenesis to identify the critical amino acid residues of PB1 for interaction with PA in vivo. The first 12 amino acids of PB1 were found to constitute the core of the interaction interface, thus narrowing the previous boundaries of domain α. The role of the minimal PB1 domain α in influenza virus gene expression and genome replication was subsequently analyzed by evaluating the activity of a set of PB1 mutants in a model reporter minigenome system. A strong correlation was observed between a functional PA binding site on PB1 and P activity. Influenza viruses bearing mutant PB1 genes were recovered using a plasmid-based influenza virus reverse genetics system. Interestingly, mutations that rendered PB1 unable to bind PA were either nonviable or severely growth impaired. These data are consistent with an essential role for the N terminus of PB1 in binding PA, P activity, and virus growth.

scholarly journals Plasticity of the Influenza Virus H5 HA Protein

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huihui Kong ◽  
David F. Burke ◽  
Tiago Jose da Silva Lopes ◽  
Kosuke Takada ◽  
Masaki Imai ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Mammalian Cells ◽  
Influenza A ◽  
Viral Antigen ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Highly Pathogenic ◽  
Antigenic Properties ◽  
Ha Protein

ABSTRACT Since the emergence of highly pathogenic avian influenza viruses of the H5 subtype, the major viral antigen, hemagglutinin (HA), has undergone constant evolution, resulting in numerous genetic and antigenic (sub)clades. To explore the consequences of amino acid changes at sites that may affect the antigenicity of H5 viruses, we simultaneously mutated 17 amino acid positions of an H5 HA by using a synthetic gene library that, theoretically, encodes all combinations of the 20 amino acids at the 17 positions. All 251 mutant viruses sequenced possessed ≥13 amino acid substitutions in HA, demonstrating that the targeted sites can accommodate a substantial number of mutations. Selection with ferret sera raised against H5 viruses of different clades resulted in the isolation of 39 genotypes. Further analysis of seven variants demonstrated that they were antigenically different from the parental virus and replicated efficiently in mammalian cells. Our data demonstrate the substantial plasticity of the influenza virus H5 HA protein, which may lead to novel antigenic variants. IMPORTANCE The HA protein of influenza A viruses is the major viral antigen. In this study, we simultaneously introduced mutations at 17 amino acid positions of an H5 HA expected to affect antigenicity. Viruses with ≥13 amino acid changes in HA were viable, and some had altered antigenic properties. H5 HA can therefore accommodate many mutations in regions that affect antigenicity. The substantial plasticity of H5 HA may facilitate the emergence of novel antigenic variants.

scholarly journals Cloning recombinant pHW2000 vector carrying the HA gene for preparation of the primary influenza A/H5N1 vaccine strain

2017 ◽  
Vol 33 (1S) ◽  
Author(s):  
Nguyen Thi Thu Hang ◽  
Hoang Thi Thu Hang ◽  
Nguyen Hung Chi ◽  
Chu Hoang Ha ◽  
Nguyen Trung Nam
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Influenza A ◽  
Reverse Genetics ◽  
Genetic Relationships ◽  
Highly Pathogenic ◽  
Ha Gene ◽  
H5n1 Influenza ◽  
Hpai H5n1 ◽  
Clade 2.3.2.1C

Influenza A/H5N1 virus evolves rapidly and generate new variants, therefore it is essential to develop effective vaccines against the currently circulating influenza strains. Among clades and subclades of highly pathogenic avian influenza (HPAI) H5N1 viruses circulating in Vietnam, H5N1 clade 1.1 and clade 2.3.2.1c possess genetic relationships to many strains of influenza; thus they are suggested to be used for producing vaccines against avian influenza. In this article, two HA gene segments of two types of A/H5N1 influenza clade have been designed: HA clade 1.1 gene consists 1825 nucleotides encoding 565 amino acids, HA clade 2.3.2.1c gene consists 1822 nucleotides, encoding 564 amino acids. Most importantly, nucleotide sequence of the pathogenic region of HA was removed. Each of the two HA segments corresponding to the two clades were successfully cloned into pHW2000 vector and will be used as a candidate for production of avian influenza vaccines using reverse genetics technique.  

Sign in / Sign up

Export Citation Format

Share Document