RESUMO
In March 2024, the US Department of Agriculture's Animal and Plant Health Inspection Service reported detection of highly pathogenic avian influenza (HPAI) A(H5N1) virus in dairy cattle in the United States for the first time. One factor that determines susceptibility to HPAI H5N1 infection is the presence of specific virus receptors on host cells; however, little is known about the distribution of the sialic acid (SA) receptors in dairy cattle, particularly in mammary glands. We compared the distribution of SA receptors in the respiratory tract and mammary gland of dairy cattle naturally infected with HPAI H5N1. The respiratory and mammary glands of HPAI H5N1-infected dairy cattle are rich in SA, particularly avian influenza virus-specific SA α2,3-gal. Mammary gland tissues co-stained with sialic acids and influenza A virus nucleoprotein showed predominant co-localization with the virus and SA α2,3-gal. HPAI H5N1 exhibited epitheliotropism within the mammary gland, and we observed rare immunolabeling within macrophages.
Assuntos
Virus da Influenza A Subtipo H5N1 , Glândulas Mamárias Animais , Infecções por Orthomyxoviridae , Receptores de Superfície Celular , Animais , Bovinos , Glândulas Mamárias Animais/virologia , Feminino , Virus da Influenza A Subtipo H5N1/patogenicidade , Virus da Influenza A Subtipo H5N1/genética , Infecções por Orthomyxoviridae/virologia , Infecções por Orthomyxoviridae/veterinária , Receptores de Superfície Celular/metabolismo , Doenças dos Bovinos/virologia , Indústria de Laticínios , Ácido N-Acetilneuramínico/metabolismo , Receptores Virais/metabolismo , Influenza Aviária/virologiaRESUMO
This study focused on intestinal restitution including phenotype switching of absorptive enterocytes and the abundance of different enterocyte subtypes in weaned pigs after porcine epidemic diarrhea virus (PEDV) infection. At 10 days post-PEDV-inoculation, the ratio of villus height to crypt depth in both jejunum and ileum had restored, and the PEDV antigen was not detectable. However, enterocytes at the villus tips revealed epithelial-mesenchymal transition (EMT) in the jejunum in which E-cadherin expression decreased while expression of N-cadherin, vimentin, and Snail increased. Additionally, there was reduced expression of actin in microvilli and Zonula occludens-1 (ZO-1) in tight junctions. Moreover, the protein concentration of transforming growth factor ß1 (TGFß1), which mediates EMT and cytoskeleton alteration, was increased. We also found a decreased number of Peyer's patch M cells in the ileum. These results reveal incomplete restitution of enterocytes in the jejunum and potentially impaired immune surveillance in the ileum after PEDV infection.