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Primary #bovine embryonic #fibroblasts support seasonal #influenza A virus #infection and demonstrate variable #fitness of #HPAI #H5N1

Abstract

The emergence of highly pathogenic avian influenza (HPAI) H5N1 (clade 2.3.4.4b, genotype B3.13) in dairy cattle presents substantial challenges to the agricultural sector and public health. Mechanistic studies of infection and transmission in cattle have proven difficult due to animal handling restrictions as well as limited availability of established cell culture models. Primary Bovine Embryonic Fibroblasts (BeEFs) were collected from a Montana cow and are investigated here as a model to study influenza A virus (IAV) infection dynamics. We compared sialylation profiles, infectious virus production, viral replication, and plaque morphology in both BeEFs and chicken DF-1 cells following infection with the bovine HPAI H5N1 and an earlier 2.3.4.4b genotype (B1.1) isolated in 2022. The data presented here show increased viral fitness of the bovine origin HPAI H5N1 strains across multiple species and bovine susceptibility to human seasonal IAV. This study highlights the ability of BeEFs to serve as a model for studying IAV infections in bovine hosts.


Competing Interest Statement

The authors have declared no competing interest.

Funder Information Declared

United States Department of Agriculture, https://ror.org/01na82s61, 35208-11567

Montana Agricultural Experiment Station (MAES), MONB00443

HHS | NIH | National Institute of Allergy and Infectious Diseases (NIAID), R21 AI178432-01, N7593021C00045

HHS | NIH | National Institute of General Medical Sciences (NIGMS), P20GM12549

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.07.26.666677v1

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