scholarly journals Molecular determinants of pathogenicity and host specificity of highly pathogenic h5N1 BiH isolates

2019 ◽  
Vol 49 ◽  
Author(s):  
Teufik Goletić ◽  
Abdulah Gagić ◽  
Vladimir Savić ◽  
Emina Rešidbegović ◽  
Aida Kavazović ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Host Specificity ◽  
Pcr Amplification ◽  
Influenza Viruses ◽  
Viral Rna ◽  
Amino Acid Residues ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Cygnus Olor

ABSTRACT Background: Towards preparation for a possible influenza pandemic, investigation of the molecular characteristics of the circulating avian H5N1 influenza virus strains is of crucial importance. These H5N1 viruses continue to spread, to infect animals and humans and to evolve and diversify providing so an ever-looming pandemic threat.Aim: To identify genetic structure and molecular biological characteristics of BiH's isolates of H5N1 HPAI as well as to assess the level of pathogenicity, phylogenetic origin and host- specificity of the isolates.Material and Methods: SPF embryonated chicken eggs were used for virus isolation. Viral RNA extracted using QIAamp viral RNA kit and manufacturer’s protocol (QIAGEN®) was used for PCR amplification. cDNA synthesis and PCR amplification of the coding region, using gene specific primer sets (primer sequences available on request), were carried out for all eight viral RNA segments separately. The Prism Big Dye Terminator v1.1 cycle sequencing kit (Applied Biosystems) was used and products were analyzed on an automatic ABI PRISM 3130 genetic analyzer (Applied Biosystems). Nucleotide sequences were analyzed using Bioedit software (v. 7.0.9.0) with an engine based on the ClustalW 1.4 algorithm. MEGA software (v. 4,0), using the neighbor joining tree inference analysis with the Tamura-Nei γ-model, was used to estimate phylogenies and calculate bootstrap values from the nucleotide sequences.Results: Full-length nucleotide sequences of the A/Cygnus olor/BIH/1/2006 (H5N1) strain were deposited in EMBL Nucleotide Sequence Database under accession nos. FN186008 to FN186014 and FM20943. The pathogenicity and host specificity of this strain, as polygenic traits, are determined in silico by the structure of its proteins, especially surface glycoproteins, HA and NA. Multibasic amino acid stretch PQGERRRKKR/GLF, marker of strains highly pathogenic to poultry, was present at the HA cleavage site of BiH strain. The RBS was typical for avian influenza viruses and contained Gln and Gly at positions 238 and 240 (H5 numbering) that is,226 and 228 according to H3 numbering with seven potential glycosylated sites but with increased binding to alpha2-6 sialoglycans thanks to substitutions, as follows, 110N, 171N, 171N, 172A, 205R and 251P. NA structure assigned this strain to the Z genotype, characterized also by the deletion of the five amino acid residues of the NS1 protein (positions 80-84). Amino acid residues, typical for the avian influenza viruses, were revealed in 40 out of 43 positions of M1, M2, NP, PA, PB2 and HA, determining the host range specificity. Phylogenetic analysis of the HA gene revealed that BiH isolates belonged to genetic clade 2.2., and presence of aspartic acid at the position of 403 of HA locate BiH isolates in 2.2.2. sub-clade.Conclusions: The BiH’s isolates were determined as HPAI virus with genes sequences closely related to A/Cygnus olor/Astrakhan/Ast05-2-10/2005 (H5N1). Three residues (M2 - 28V and 78K, NP - 33I), typical of human influenza viruses, were found, indicating a certain degree of intercurrent evolutionary adaptive changes in BiH isolates. Sequence comparison of HA and NA segments with relevant sequences in GenBank revealed that the BiH isolates and the ones from the southern Russia (Astrakhan region) group together phylogenetically, forming a monophyleticcluster in both genes indicating that these isolates have evolved from the same origin. Sequence derived phenotype markers of NA protein (E99, V129, D131, R136, H255 and Y256) as well as of M2 protein (26L, 27V, 30A, S31 and G34) showed that the isolates have an oseltamivir and amantadine sensitive genotype. 

scholarly journals Two amino acid residues in the matrix protein M1 contribute to the virulence difference of H5N1 avian influenza viruses in mice

Virology ◽  
2009 ◽  
Vol 384 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Shufang Fan ◽  
Guohua Deng ◽  
Jiasheng Song ◽  
Guobin Tian ◽  
Yongbing Suo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Matrix Protein ◽  
Influenza Viruses ◽  
Amino Acid Residues ◽  
Avian Influenza Viruses ◽  
H5n1 Avian Influenza ◽  
The Matrix ◽  
Matrix Protein M1

scholarly journals Amino acid residues at positions 222 and 227 of the hemagglutinin together with the neuraminidase determine binding of H5 avian influenza viruses to sialyl Lewis X

2015 ◽  
Vol 161 (2) ◽  
pp. 307-316 ◽  
Author(s):  
Takahiro Hiono ◽  
Masatoshi Okamatsu ◽  
Manabu Igarashi ◽  
Ryan McBride ◽  
Robert P. de Vries ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Influenza Viruses ◽  
Sialyl Lewis X ◽  
Amino Acid Residues ◽  
Avian Influenza Viruses ◽  
Lewis X ◽  
Sialyl Lewis

scholarly journals Emergence of Highly Pathogenic Avian Influenza A(H5N1) Virus PB1-F2 Variants and Their Virulence in BALB/c Mice

2015 ◽  
Vol 89 (11) ◽  
pp. 5835-5846 ◽  
Author(s):  
Ram P. Kamal ◽  
Amrita Kumar ◽  
Charles T. Davis ◽  
Wen-Pin Tzeng ◽  
Tung Nguyen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Full Length ◽  
Start Codon ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Mammalian Infection ◽  
Pathogenic H5n1

ABSTRACTInfluenza A viruses (IAVs) express the PB1-F2 protein from an alternate reading frame within the PB1 gene segment. The roles of PB1-F2 are not well understood but appear to involve modulation of host cell responses. As shown in previous studies, we find that PB1-F2 proteins of mammalian IAVs frequently have premature stop codons that are expected to cause truncations of the protein, whereas avian IAVs usually express a full-length 90-amino-acid PB1-F2. However, in contrast to other avian IAVs, recent isolates of highly pathogenic H5N1 influenza viruses had a high proportion of PB1-F2 truncations (15% since 2010; 61% of isolates in 2013) due to several independent mutations that have persisted and expanded in circulating viruses. One natural H5N1 IAV containing a mutated PB1-F2 start codon (i.e., lacking ATG) was 1,000-fold more virulent for BALB/c mice than a closely related H5N1 containing intact PB1-F2.In vitro, we detected expression of an in-frame protein (C-terminal PB1-F2) from downstream ATGs in PB1-F2 plasmids lacking the well-conserved ATG start codon. Transient expression of full-length PB1-F2, truncated (24-amino-acid) PB1-F2, and PB1-F2 lacking the initiating ATG in mammalian and avian cells had no effect on cell apoptosis or interferon expression in human lung epithelial cells. Full-length and C-terminal PB1-F2 mutants colocalized with mitochondria in A549 cells. Close monitoring of alterations of PB1-F2 and their frequency in contemporary avian H5N1 viruses should continue, as such changes may be markers for mammalian virulence.IMPORTANCEAlthough most avian influenza viruses are harmless for humans, some (such as highly pathogenic H5N1 avian influenza viruses) are capable of infecting humans and causing severe disease with a high mortality rate. A number of risk factors potentially associated with adaptation to mammalian infection have been noted. Here we demonstrate that the protein PB1-F2 is frequently truncated in recent isolates of highly pathogenic H5N1 viruses. Truncation of PB1-F2 has been proposed to act as an adaptation to mammalian infection. We show that some forms of truncation of PB1-F2 may be associated with increased virulence in mammals. Our data support the assessment of PB1-F2 truncations for genomic surveillance of influenza viruses.

scholarly journals Isolation and Characterization of Avian Influenza Viruses, Including Highly Pathogenic H5N1, from Poultry in Live Bird Markets in Hanoi, Vietnam, in 2001

2005 ◽  
Vol 79 (7) ◽  
pp. 4201-4212 ◽  
Author(s):  
Doan C. Nguyen ◽  
Timothy M. Uyeki ◽  
Samadhan Jadhao ◽  
Taronna Maines ◽  
Michael Shaw ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Influenza Viruses ◽  
Common Source ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Live Bird Markets ◽  
Isolation And Characterization ◽  
High Amino Acid ◽  
Live Bird

ABSTRACT Since 1997, outbreaks of highly pathogenic (HP) H5N1 and circulation of H9N2 viruses among domestic poultry in Asia have posed a threat to public health. To better understand the extent of transmission of avian influenza viruses (AIV) to humans in Asia, we conducted a cross-sectional virologic study in live bird markets (LBM) in Hanoi, Vietnam, in October 2001. Specimens from 189 birds and 18 environmental samples were collected at 10 LBM. Four influenza A viruses of the H4N6 (n = 1), H5N2 (n = 1), and H9N3 (n = 2) subtypes were isolated from healthy ducks for an isolation frequency of over 30% from this species. Two H5N1 viruses were isolated from healthy geese. The hemagglutinin (HA) genes of these H5N1 viruses possessed multiple basic amino acid motifs at the cleavage site, were HP for experimentally infected chickens, and were thus characterized as HP AIV. These HA genes shared high amino acid identities with genes of other H5N1 viruses isolated in Asia during this period, but they were genetically distinct from those of H5N1 viruses isolated from poultry and humans in Vietnam during the early 2004 outbreaks. These viruses were not highly virulent for experimentally infected ducks, mice, or ferrets. These results establish that HP H5N1 viruses with properties similar to viruses isolated in Hong Kong and mainland China circulated in Vietnam as early as 2001, suggest a common source for H5N1 viruses circulating in these Asian countries, and provide a framework to better understand the recent widespread emergence of HP H5N1 viruses in Asia.

scholarly journals Genetic Characterization and Pathogenesis of Avian Influenza Virus H7N3 Isolated from Spot-Billed Ducks in South Korea, Early 2019

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 856
Author(s):  
Thuy-Tien Thi Trinh ◽  
Indira Tiwari ◽  
Kaliannan Durairaj ◽  
Bao Tuan Duong ◽  
Anh Thi Viet Nguyen ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Avian Influenza ◽  
South Korea ◽  
Avian Influenza Virus ◽  
Post Infection ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic

Low-pathogenicity avian influenza viruses (LPAIV) introduced by migratory birds circulate in wild birds and can be transmitted to poultry. These viruses can mutate to become highly pathogenic avian influenza viruses causing severe disease and death in poultry. In March 2019, an H7N3 avian influenza virus—A/Spot-billed duck/South Korea/WKU2019-1/2019 (H7N3)—was isolated from spot-billed ducks in South Korea. This study aimed to evaluate the phylogenetic and mutational analysis of this isolate. Molecular analysis revealed that the genes for HA (hemagglutinin) and NA (neuraminidase) of this strain belonged to the Central Asian lineage, whereas genes for other internal proteins such as polymerase basic protein 1 (PB1), PB2, nucleoprotein, polymerase acidic protein, matrix protein, and non-structural protein belonged to that of the Korean lineage. In addition, a monobasic amino acid (PQIEPR/GLF) at the HA cleavage site, and the non-deletion of the stalk region in the NA gene indicated that this isolate was a typical LPAIV. Nucleotide sequence similarity analysis of HA revealed that the highest homology (99.51%) of this isolate is to that of A/common teal/Shanghai/CM1216/2017 (H7N7), and amino acid sequence of NA (99.48%) was closely related to that of A/teal/Egypt/MB-D-487OP/2016 (H7N3). An in vitro propagation of the A/Spot-billed duck/South Korea/WKU2019-1/2019(H7N3) virus showed highest (7.38 Log10 TCID50/mL) virus titer at 60 h post-infection, and in experimental mouse lungs, the virus was detected at six days’ post-infection. Our study characterizes genetic mutations, as well as pathogenesis in both in vitro and in vivo model of a new Korea H7N3 viruses in 2019, carrying multiple potential mutations to become highly pathogenic and develop an ability to infect humans; thus, emphasizing the need for routine surveillance of avian influenza viruses in wild birds.

scholarly journals SUMOylation of matrix protein M1 and filamentous morphology collectively contribute to the replication and virulence of highly pathogenic H5N1 avian influenza viruses in mammals

2021 ◽  
Author(s):  
Jing Guo ◽  
Jianing Chen ◽  
Yuanyuan Li ◽  
Yanbing Li ◽  
Guohua Deng ◽  
...  
Keyword(s):  
Amino Acid ◽  
Avian Influenza ◽  
Matrix Protein ◽  
Highly Pathogenic Avian Influenza ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
H5n1 Influenza ◽  
Matrix Protein M1

The matrix protein (M1) of influenza A virus plays an important role in replication, assembly, and budding. A previous study found that aspartic acid (D) at position 30 and alanine (A) at position 215 of M1 contribute to the high pathogenicity of H5N1 viruses in mice, and double mutations of D to asparagine (N) at position 30 (D30N) and A to threonine (T) at position 215 (A215T) in M1 dramatically attenuate H5N1 viruses in mice. However, the underlying mechanisms by which these M1 mutations attenuate the virulence of H5N1 viruses are unknown. Here, we found that the amino acid mutation A215T eliminates the SUMOylation of M1 by reducing its interaction with the host SUMO1 protein, significantly reducing the stability of M1, slowing the export of the M1-vRNP complex from the nucleus to the cytoplasm, and reducing viral replication in MDCK cells. We further found that the D30N mutation in M1 alters the shape of progeny viruses from filamentous to spherical virions. Our findings reveal an essential role for M1 215A SUMOylation and M1 30D-related filamentous morphology in the pathogenesis of avian influenza viruses, which could be targeted in novel antiviral drug designs. Importance Identification of the pathogenic mechanism of highly pathogenic avian influenza viruses in mammals is helpful to develop novel anti-influenza virus strategies. Two amino acid mutations (D30N and A215T) in M1 were found to collectively attenuate H5N1 influenza viruses in mice, but the underlying mechanism remained unknown. This study found that the A215T mutation significantly decreases the SUMOylation of M1, which in turn attenuates the replication of H5N1 virus in mammalian cells. The D30N mutation in M1 was found to change the virion shape from filamentous to spherical. These findings are important for understanding the molecular mechanism of virulence of highly pathogenic avian influenza viruses in mammals.

scholarly journals H5N2 Avian Influenza Outbreak in Texas in 2004: the First Highly Pathogenic Strain in the United States in 20 Years?

2005 ◽  
Vol 79 (17) ◽  
pp. 11412-11421 ◽  
Author(s):  
Chang-Won Lee ◽  
David E. Swayne ◽  
Jose A. Linares ◽  
Dennis A. Senne ◽  
David L. Suarez
Keyword(s):  
United States ◽  
Amino Acid ◽  
Avian Influenza ◽  
Cleavage Site ◽  
Basic Amino Acid ◽  
The United States ◽  
Influenza Viruses ◽  
Single Point Mutation ◽  
Highly Pathogenic

ABSTRACT In early 2004, an H5N2 avian influenza virus (AIV) that met the molecular criteria for classification as a highly pathogenic AIV was isolated from chickens in the state of Texas in the United States. However, clinical manifestations in the affected flock were consistent with avian influenza caused by a low-pathogenicity AIV and the representative virus (A/chicken/Texas/298313/04 [TX/04]) was not virulent for experimentally inoculated chickens. The hemagglutinin (HA) gene of the TX/04 isolate was similar in sequence to A/chicken/Texas/167280-4/02 (TX/02), a low-pathogenicity AIV isolate recovered from chickens in Texas in 2002. However, the TX/04 isolate had one additional basic amino acid at the HA cleavage site, which could be attributed to a single point mutation. The TX/04 isolate was similar in sequence to TX/02 isolate in several internal genes (NP, M, and NS), but some genes (PA, PB1, and PB2) had sequence of a clearly different origin. The TX/04 isolate also had a stalk deletion in the NA gene, characteristic of a chicken-adapted AIV. By analyzing viruses constructed by in vitro mutagenesis followed by reverse genetics, we found that the pathogenicity of the TX/04 virus could be increased in vitro and in vivo by the insertion of an additional basic amino acid at the HA cleavage site and not by the loss of a glycosylation site near the cleavage site. Our study provides the genetic and biologic characteristics of the TX/04 isolate, which highlight the complexity of the polygenic nature of the virulence of influenza viruses.

scholarly journals Antibody responses to avian influenza viruses in wild birds broaden with age

2016 ◽  
Vol 283 (1845) ◽  
pp. 20162159 ◽  
Author(s):  
Sarah C. Hill ◽  
Ruth J. Manvell ◽  
Bodo Schulenburg ◽  
Wendy Shell ◽  
Paul S. Wikramaratna ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Haemagglutination Inhibition ◽  
Wild Birds ◽  
Influenza Viruses ◽  
Antibody Responses ◽  
Immune Recognition ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Age Related ◽  
Pathogenic H5n1

For viruses such as avian influenza, immunity within a host population can drive the emergence of new strains by selecting for viruses with novel antigens that avoid immune recognition. The accumulation of acquired immunity with age is hypothesized to affect how influenza viruses emerge and spread in species of different lifespans. Despite its importance for understanding the behaviour of avian influenza viruses, little is known about age-related accumulation of immunity in the virus's primary reservoir, wild birds. To address this, we studied the age structure of immune responses to avian influenza virus in a wild swan population ( Cygnus olor ), before and after the population experienced an outbreak of highly pathogenic H5N1 avian influenza in 2008. We performed haemagglutination inhibition assays on sampled sera for five avian influenza strains and show that breadth of response accumulates with age. The observed age-related distribution of antibody responses to avian influenza strains may explain the age-dependent mortality observed during the highly pathogenic H5N1 outbreak. Age structures and species lifespan are probably important determinants of viral epidemiology and virulence in birds.

Opposite outcomes of the within-host competition between highly and low pathogenic H5N8 avian influenza viruses in chickens compared to ducks

2021 ◽  
Author(s):  
Pierre Bessière ◽  
Thomas Figueroa ◽  
Amelia Coggon ◽  
Charlotte Foret-Lucas ◽  
Alexandre Houffschmitt ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Reverse Genetics ◽  
Highly Pathogenic Avian Influenza ◽  
Viral Evolution ◽  
Influenza Viruses ◽  
Poultry Production ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Low Pathogenic Avian Influenza

Highly pathogenic avian influenza viruses (HPAIV) emerge from low pathogenic avian influenza viruses (LPAIV) through the introduction of basic amino acids at the hemagglutinin (HA) cleavage site. Following viral evolution, the newly formed HPAIV likely represents a minority variant within the index host, predominantly infected with the LPAIV precursor. Using reverse-genetics engineered H5N8 viruses differing solely at the HA cleavage, we tested the hypothesis that the interaction between the minority HPAIV and the majority LPAIV could modulate the risk of HPAIV emergence and that the nature of the interaction could depend on the host species. In chickens, we observed that the H5N8 LP increased H5N8 HP replication and pathogenesis. By contrast, the H5N8 LP antagonized H5N8 HP replication and pathogenesis in ducks. Ducks mounted a more potent antiviral innate immune response than chickens against the H5N8 LP , which correlated with H5N8 HP inhibition. These data provide experimental evidence that HPAIV may be more likely to emerge in chickens than in ducks and underscore the importance of within-host viral variants interactions in viral evolution. IMPORTANCE Highly pathogenic avian influenza viruses represent a threat to poultry production systems and to human health because of their impact on food security and because of their zoonotic potential. It is therefore crucial to better understand how these viruses emerge. Using a within-host competition model between highly and low pathogenic avian influenza viruses, we provide evidence that highly pathogenic avian influenza viruses could be more likely to emerge in chickens than in ducks. These results have important implications for highly pathogenic avian influenza virus emergence prevention and they underscore the importance of within-host viral variants interactions in virus evolution.

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