Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US
Highly pathogenic avian influenza viruses (HPAIV) pose serious public health concerns. In March 2024, a first-time outbreak of HPAIV H5N1 in dairy cattle herds was reported in the United States (US). Since then, the virus has continued to spread in cattle herds and spilt over into humans. We recentl...
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Taylor & Francis Group
2025-12-01
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| Series: | Emerging Microbes and Infections |
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| Online Access: | https://www.tandfonline.com/doi/10.1080/22221751.2025.2542247 |
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| author | Mahmoud Bayoumi Ramya S. Barre Ruby A. Escobedo Vinay Shivanna Nathanial Jackson Chengjin Ye Adolfo García-Sastre Ahmed Mostafa Luis Martinez-Sobrido |
| author_facet | Mahmoud Bayoumi Ramya S. Barre Ruby A. Escobedo Vinay Shivanna Nathanial Jackson Chengjin Ye Adolfo García-Sastre Ahmed Mostafa Luis Martinez-Sobrido |
| author_sort | Mahmoud Bayoumi |
| collection | DOAJ |
| description | Highly pathogenic avian influenza viruses (HPAIV) pose serious public health concerns. In March 2024, a first-time outbreak of HPAIV H5N1 in dairy cattle herds was reported in the United States (US). Since then, the virus has continued to spread in cattle herds and spilt over into humans. We recently showed that the first human isolate reported in the US in Texas (HPhTX) from a dairy worker in an affected cattle farm has enhanced replication kinetics and pathogenicity in mice compared to a closely related bovine isolate (HPbTX). Herein, we show that HPhTX has enhanced polymerase activity, compared with HPbTX, in human cells and that the polymerase basic 2 (PB2) protein is the main factor responsible for this difference. Through single and combined site-directed mutagenesis and swapping the three amino acids different between HPhTX and HPbTX, we found that PB2 mutation E627K is the major contributor to the enhanced polymerase activity of HPhTX. E362G substitution in HPhTX PB2 affected the polymerase, although to a lesser extent than E627K. Moreover, M631L mutation in HPhTX PB2 enhanced polymerase activity. Rescue of a loss-of-function recombinant HPhTX (rHPhTX) containing mutations at residues 627 and 362, alone or in combination, revealed a contribution of PB2 E362G and K627E in morbidity, mortality, and viral replication as compared to rHPhTX wild-type (WT), and significantly reduced viral pathogenicity to levels comparable to rHPbTX WT. These findings indicate that HPAIV H5N1 of cattle origin has post-transmission amino acid changes that increase viral replication in human cells and pathogenicity in mice. |
| format | Article |
| id | doaj-art-a03e1f45e8b14cad93880a9da2698d75 |
| institution | Kabale University |
| issn | 2222-1751 |
| language | English |
| publishDate | 2025-12-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Emerging Microbes and Infections |
| spelling | doaj-art-a03e1f45e8b14cad93880a9da2698d752025-08-20T15:15:22ZengTaylor & Francis GroupEmerging Microbes and Infections2222-17512025-12-0114110.1080/22221751.2025.2542247Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, USMahmoud Bayoumi0Ramya S. Barre1Ruby A. Escobedo2Vinay Shivanna3Nathanial Jackson4Chengjin Ye5Adolfo García-Sastre6Ahmed Mostafa7Luis Martinez-Sobrido8Host-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USASouthwest National Primate Research Center at the Texas Biomedical Research Institute, San Antonio, TX, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USADepartment of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USAHost-pathogen interactions (HPI) and Disease Intervention and Prevention (DIP) Programs, Texas Biomedical Research Institute, San Antonio, TX, USAHighly pathogenic avian influenza viruses (HPAIV) pose serious public health concerns. In March 2024, a first-time outbreak of HPAIV H5N1 in dairy cattle herds was reported in the United States (US). Since then, the virus has continued to spread in cattle herds and spilt over into humans. We recently showed that the first human isolate reported in the US in Texas (HPhTX) from a dairy worker in an affected cattle farm has enhanced replication kinetics and pathogenicity in mice compared to a closely related bovine isolate (HPbTX). Herein, we show that HPhTX has enhanced polymerase activity, compared with HPbTX, in human cells and that the polymerase basic 2 (PB2) protein is the main factor responsible for this difference. Through single and combined site-directed mutagenesis and swapping the three amino acids different between HPhTX and HPbTX, we found that PB2 mutation E627K is the major contributor to the enhanced polymerase activity of HPhTX. E362G substitution in HPhTX PB2 affected the polymerase, although to a lesser extent than E627K. Moreover, M631L mutation in HPhTX PB2 enhanced polymerase activity. Rescue of a loss-of-function recombinant HPhTX (rHPhTX) containing mutations at residues 627 and 362, alone or in combination, revealed a contribution of PB2 E362G and K627E in morbidity, mortality, and viral replication as compared to rHPhTX wild-type (WT), and significantly reduced viral pathogenicity to levels comparable to rHPbTX WT. These findings indicate that HPAIV H5N1 of cattle origin has post-transmission amino acid changes that increase viral replication in human cells and pathogenicity in mice.https://www.tandfonline.com/doi/10.1080/22221751.2025.2542247Avian influenzaHPAIVH5N1minigenome assayPB2spillover |
| spellingShingle | Mahmoud Bayoumi Ramya S. Barre Ruby A. Escobedo Vinay Shivanna Nathanial Jackson Chengjin Ye Adolfo García-Sastre Ahmed Mostafa Luis Martinez-Sobrido Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US Emerging Microbes and Infections Avian influenza HPAIV H5N1 minigenome assay PB2 spillover |
| title | Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US |
| title_full | Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US |
| title_fullStr | Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US |
| title_full_unstemmed | Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US |
| title_short | Identification of amino acid residues in polymerase PB2 responsible for differential replication and pathogenicity of avian influenza virus H5N1 isolated from human and cattle in Texas, US |
| title_sort | identification of amino acid residues in polymerase pb2 responsible for differential replication and pathogenicity of avian influenza virus h5n1 isolated from human and cattle in texas us |
| topic | Avian influenza HPAIV H5N1 minigenome assay PB2 spillover |
| url | https://www.tandfonline.com/doi/10.1080/22221751.2025.2542247 |
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