#pb2 — Public Fediverse posts

A suivre :
La suite des dernières fiches-Espèce publiées en mars-avril 2026, sur le site en DORIS.ffessm.fr, avec leur lien respectif.

C'est donc la seconde rafale pour #rattrapage ! :-D

#biodiversite #plongéeBio #ffessm #cnebs #Pb1 #pB2 #Fb1 #Fb2 #Fb3 #version4dusite #biodiversity

A suivre :
Les dernières fiches-Espèce publiées en mars-avril 2026, sur le site en DORIS.ffessm.fr, avec leur lien respectif.

#biodiversite #plongéeBio #ffessm #cnebs #Pb1 #pB2 #Fb1 #Fb2 #Fb3 #version4dusite

#Update: First locally acquired #human case of #H7N7 #influenza A was detected in #Taiwan (CDC, May 5 '26), https://etidiohnew.blogspot.com/2026/05/update-first-locally-acquired-human.html

''Further analysis showed that the virus's #PB2 gene carries the E627K mutation (PB2 E627K).'' {indicating mammalian adaptation during human infection}.

Historical #Pandemic and Contemporary #Influenza A Viruses Reveal #PB2 M631L as a Convergent #Adaptation to #Human ANP32, https://etidiohnew.blogspot.com/2026/04/historical-pandemic-and-contemporary.html

''Of the nine D1.1 #infections in #humans, three viruses acquired #PB2 #mammalian #adaptations: D701N in A/Nevada/10/2025 and E627K in A/Wyoming/01/2025 and A/British Columbia/PHL-2032/2024''

Emergence of #mammalian-adaptive #PB2 #mutations enhances #polymerase activity and #pathogenicity of #cattle-derived #H5N1 #influenza A virus, https://etidiohnew.blogspot.com/2025/12/emergence-of-mammalian-adaptive-pb2.html

Evolutionary trajectories and #zoonotic #potential of a #PB2 #mutation triad (I147T, K339T, and A588T) in avian #influenza viruses, https://etidiohnew.blogspot.com/2025/12/evolutionary-trajectories-and-zoonotic.html

An emerging #PB2-627 #polymorphism increases the #zoonotic #risk of avian #influenza virus by overcoming ANP32 host restriction in mammalian and avian hosts, https://etidiohnew.blogspot.com/2025/08/an-emerging-pb2-627-polymorphism.html

Glutamic Acid at Position 343 in #PB2 Contributes to the #Virulence of #H1N1 #Swine #Influenza Virus in Mice, https://etidiohnew.blogspot.com/2025/07/glutamic-acid-at-position-343-in-pb2.html

E627V #mutation in #PB2 protein promotes the #mammalian #adaptation of novel #H10N3 avian #influenza virus, https://etidiohnew.blogspot.com/2025/06/e627v-mutation-in-pb2-protein-promotes.html

Immediate #PB2-E627K amino acid #substitution after single #infection of highly pathogenic avian #influenza #H5N1 clade 2.3.4.4b in mice, https://etidiohnew.blogspot.com/2025/06/immediate-pb2-e627k-amino-acid.html

A rapid #review of the avian #influenza #PB2 #E627K #mutation in #human infection studies, https://etidiohnew.blogspot.com/2025/04/a-rapid-review-of-avian-influenza.html

Synergistic effects of PA (S184N) and #PB2 (E627K) #mutations on the increased pathogenicity of #H3N2 canine #influenza virus #infections in mice and #dogs, https://etidiohnew.blogspot.com/2025/04/synergistic-effects-of-pa-s184n-and-pb2.html

Cross-species and #mammal-to-mammal #transmission of clade 2.3.4.4b highly pathogenic avian #influenza A #H5N1 with #PB2 adaptations, https://etidiohnew.blogspot.com/2025/03/cross-species-and-mammal-to-mammal.html

{#USA, #Nevada} The Occurrence of Another Highly Pathogenic Avian #Influenza (HPAI) #Spillover from Wild #Birds into Dairy #Cattle, https://etidiohnew.blogspot.com/2025/02/usa-nevada-occurrence-of-another-highly.html

Analysis of hemagglutinin gene of Nevada dairy cattle viruses did not identify changes predicted to impact #infectivity or #adaptation to mammalian hosts. However, a change of #PB2 D701N commonly associated with mammalian adaptation of HPAI virus was identified in viruses sequenced from four separate dairy cattle.

''Compared to the Svalbard avian index case, #PB2 #segment of the walrus sequence contained only 2 aa #substitutions, including #E627K mutation, which is known to enhance #infectivity in #mammals. Interestingly, all avian HPAIV H5N5 from Norway, as well as the walrus sequence, have a set of 6 aa in PB2 that have been reported to favour infection of mammals [Citation11].''

#Chicken ANP32A-independent #replication of highly pathogenic avian #influenza viruses potentially leads to #mammalian #adaptation-related amino acid substitutions in viral #PB2 and #PA proteins

Source: Journal of Virology, ABSTRACTAcidic nuclear phosphoprotein 32 family member A (ANP32A) is an important host factor that supports the efficient replication of avian influenza viruses (AIVs). To develop an antiviral strategy against Gs/Gd-lineage H5 highly pathogenic…

https://etidioh.wordpress.com/2024/11/21/chicken-anp32a-independent-replication-of-highly-pathogenic-avian-influenza-viruses-potentially-leads-to-mammalian-adaptation-related-amino-acid-substitutions-in-viral-pb2-and-pa-proteins/

Characterization of #H5N1 avian #influenza virus isolated from #bird in #Russia with the #E627K mutation in the #PB2 protein

Source: Scientific Reports, AbstractCurrently A(H5Nx) avian influenza viruses are globally widespread and continue to evolve. Since their emergence in 2020 novel highly pathogenic avian influenza A(H5N1) clade 2.3.4.4b reassortant viruses have become predominant in the world and caused multiple infections in mammals. It was shown that some of…

https://etidioh.wordpress.com/2024/11/04/characterization-of-h5n1-avian-influenza-virus-isolated-from-bird-in-russia-with-the-e627k-mutation-in-the-pb2-protein/

An emerging #PB2-627 #polymorphism increases #pandemic #potential of avian #influenza virus by breaking through ANP32 host restriction in #mammalian & avian hosts, BioRxIV: https://www.biorxiv.org/content/10.1101/2024.07.03.601996v4

by screening the global PB2 seq., we discovered a new independent cluster with PB2-627V emerged in the '10s, which is prevalent in various avian, mammalian, & human isolates of AIVs, including #H9N2, #H7N9, #H3N8, 2.3.4.4b #H5N1, and other subtypes.

Decoding non- #human #mammalian adaptive #signatures of 2.3.4.4b #H5N1 to assess its human adaptive #potential, BioRxIV: https://www.biorxiv.org/content/10.1101/2024.08.26.609722v1?rss=1

H5N1 infections in mammals across time showed a unique set of adaptations in 2.3.4.4b clade compared to previously circulating strains, especially acquisition of Q591 adaptation in #PB2 that enables human adaptation.

Enhanced Diversifying #Selection on #Polymerase Genes in #H5N1 Clade 2.3.4.4b: A Key Driver of Altered #Species #Tropism and #Host Range Expansion, BioRxIV: https://www.biorxiv.org/content/10.1101/2024.08.19.606826v1?rss=1

the polymerase genes #PB2, #PB1, and #PA exhibit significantly greater selection pressures in clade 2.3.4.4b than in all the earlier H5N1 virus clades. Polymerases play critical roles in influenza virus adaptation, including viral fitness, interspecies transmission, and virulence.

#Outcome of #H5N1 clade 2.3.4.4b virus #infection in #calves and lactating #cows, BioRxIV: https://www.biorxiv.org/content/10.1101/2024.08.09.607272v1

Adaptive #mutation #PB2 #E627K emerged after intramammary #replication of H5N1 euDG. Our data suggest that in addition to H5N1 B3.13, other HPAIV H5N1 strains have potential to replicate in #udder of cows & that #milk & milking procedures, rather than respiratory spread, are likely the primary routes of H5N1 #transmission between cattle.

An emerging #PB2-627 #polymorphism increases the #pandemic #potential of avian #influenza virus by breaking through ANP32 #host #restriction in #mammalian and avian hosts, BioRxIV: https://www.biorxiv.org/content/10.1101/2024.07.03.601996v3

...we discovered a new independent #cluster with PB2-627V emerged in the 2010s, which is prevalent in various avian, mammalian, and human isolates of AIVs, including #H9N2, #H7N9, #H3N8, 2.3.4.4b #H5N1, and other subtypes.

#Genomic Characterization of #HPAI #H5N1 Virus Newly Emerged in Dairy #Cattle, Emerg Microbes Infect.: https://www.tandfonline.com/doi/full/10.1080/22221751.2024.2380421

B3.13 viruses underwent 2 #reassortment events since 2023 & exhibit critical #mutations in #HA, #M1, & #NS #genes but lack critical mutations in #PB2 & PB1 genes, which enhance virulence or adaptation to #mammals. #PB2 E627 K mutation in a #human case associated with cattle underscores the potential for rapid evolution post-infection...

Multiple #transatlantic #incursions of #HPAI clade 2.3.4.4b A(#H5N5) virus into North #America and #spillover to #mammals, Cell Rep.: https://www.cell.com/cell-reports/fulltext/S2211-1247(24)00808-8?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124724008088%3Fshowall%3Dtrue

#Seabirds likely enabled multiple incursions of A(H5N5) virus from #Europe to #Canada. Some A(H5N5) viruses possessed the mammalian #adaptation #marker #PB2-E627K. A(H5N5) viruses demonstrated rapid 100% #mortality and some transmission in #ferrets. A(H5N5) viruses preferred avian virus receptors and are sensitive to NA #inhibitors.

#Aminoacid #mutations #PB1-V719M and #PA-N444D combined with #PB2-627K contribute to the #pathogenicity of #H7N9 in #mice, Vet Res.: https://veterinaryresearch.biomedcentral.com/articles/10.1186/s13567-024-01342-6

Overall, this study revealed that #virulence in H7N9 is a #polygenic trait and identified novel virulence-related residues (PB2-627K combined with PB1-719M and/or PA-444D) in viral ribonucleoprotein (vRNP) complexes.

An emerging #PB2-627 #polymorphism increases the #pandemic #potential of avian #influenza virus by breaking through ANP32 #host restriction in #mammalian and avian #hosts, BioRxIV, https://www.biorxiv.org/content/10.1101/2024.07.03.601996v1?rss=1

The PB2-627V polymorphism has been found in birds, humans, and mammals worldwide across more than ten AIV #subtypes. Given the escalating global spread of AIVs, it is crucial to closely monitor influenza viruses carrying PB2-627V to prevent a pandemic.

... #Mutations in the #PB2 gene (#D701N and #Q591K) associated with #adaptation and #transmission in mammals were detected suggesting a potential zoonotic risk.

#Avian #flu: «for whom the bell tolls»? Vopr Virusol.: https://virusjour.crie.ru/jour/article/view/16636

#H5N1 influenza clade 2.3.4.4b strains isolated from #mammals have genetic signatures of partial #adaptation to #human body in #PB2, NP, HA, NA #genes, which play a major role in regulating #aerosol transmission & host range of virus. Current situation poses a real #threat of pre-adaptation in mammals as intermediate hosts, followed by transition of virus into human population with #catastrophic consequences.

Viruses detected in both #cows & 2 human cases maintain primarily avian genetic characteristics & lack changes that would make them better adapted to infect or transmit b/w humans. Genome of human virus from MI did not have #PB2 E627K change detected in virus from TX case, but had 1 notable change (PB2 M631L) compared to TX case that is known to be associated with viral adaptation to mammalian hosts, and which has been detected in 99% of dairy cow sequences but only sporadically in birds

#PB2 residue 473 contributes to the #mammalian #virulence of #H7N9 avian #influenza virus by modulating viral #polymerase activity via ANP32A, J Virol.: https://doi.org/10.1128/jvi.01944-23

-- In this study, we identified PB2 residue 473 as a new determinant of mouse virulence and mammalian #adaptation of the viral polymerase of the H7N9 virus and its non-pathogenic #H9N2 counterparts.

-- According to sequencing results, virus shares 99% similarity with the A/Paraná/ 20675/2022 (A/ #H1N1pdm09-like) virus previously detected in a human case from city of Toledo-Paraná in Oct 2022. #Segments #PB2, #PB1, #PA, NA, and MP corresponded to virus A/Paraná/10835/2021 (A/H1N1pdm09-like) also reported in city of Toledo, & #NP and NS #segments corresponded to virus A/Paraná/44706/2022 (A/ #H3N2v) reported in city of Santa Helena, also in the state of #Paraná