Infection of swine ex vivo tissues with avian viruses including H7N9 and correlation with glycomic analysis

Authors

  • Renee W. Y. Chan,

    1. Department of Pathology, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
    2. Centre of Influenza Research, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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  • Rositsa Karamanska,

    1. Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London, UK
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  • Sjouke Van Poucke,

    1. Faculty of Veterinary Medicine, Lab of Virology Salisburylaan 133, Merelbeke, Belgium
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  • Kristien Van Reeth,

    1. Faculty of Veterinary Medicine, Lab of Virology Salisburylaan 133, Merelbeke, Belgium
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  • Icarus W. W. Chan,

    1. Centre of Influenza Research, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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  • Michael C. W. Chan,

    1. Centre of Influenza Research, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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  • Anne Dell,

    1. Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, London, UK
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  • Joseph S. M. Peiris,

    1. Centre of Influenza Research, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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  • Stuart M. Haslam,

    Corresponding author
    1. Department of Pathology, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
    • Correspondence: Stuart M. Haslam, Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. E-mail: s.haslam@imperial.ac.uk.

      and

      John M. Nicholls, Department of Pathology, Room 127, University Pathology Building, University of Hong Kong, Pok Fu Lam Road, Pok Fu Lam, Hong Kong SAR, China. E-mail: nicholls@pathology.hku.hk

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  • Yi Guan,

    1. Centre of Influenza Research, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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  • John M. Nicholls

    Corresponding author
    1. Department of Pathology, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
    • Correspondence: Stuart M. Haslam, Division of Molecular Biosciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK. E-mail: s.haslam@imperial.ac.uk.

      and

      John M. Nicholls, Department of Pathology, Room 127, University Pathology Building, University of Hong Kong, Pok Fu Lam Road, Pok Fu Lam, Hong Kong SAR, China. E-mail: nicholls@pathology.hku.hk

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  • The copyright line for this article was changed on 29th April 2016 after original online publication.

Abstract

Objectives

Swine have been regarded as intermediate hosts in the spread of influenza from birds to humans but studies of the sialylated glycans that comprise their respiratory tract have not been extensively studied in the past. This study analyzed the sialylated N-glycan and O-glycan profile of swine trachea and lung and correlated this with ex-vivo infection of swine explants with avian influenza viruses.

Sample

Lungs and tracheal samples were obtained from normal farm and laboratory raised swine and used for ex vivo infection as well as mass spectrometric analysis. Infection of the ex vivo tissues used high pathogenic and low pathogenic avian viruses including the novel H7N9 virus that emerged in China in early 2013.

Main outcome measures

Assessment of successful replication was determined by TCID50 as well as virus immunohistochemistry. The N-glycan and O-glycan profiles were measured by MALDI-TOF and sialylated linkages were determined by sialidase treatment. Lectin binding histochemistry was also performed on formalin fixed tissue samples with positive binding detected by chromogen staining.

Results

The swine respiratory tract glycans differed from the human respiratory tact glycans in two main areas. There was a greater abundance of Gal-α-Gal linkages resulting in a relative decrease in sialylated glycans. The swine respiratory tract also had a greater proportion of glycans containing Neu5Gc and Siaα2-6 glycans than the human respiratory tract. Infection with avian viruses was confined primarily to lung bronchioles rather than trachea and parenchyma.

Conclusions

In contrast to previous studies we found that there was not as much expression of Siaα2-3 glycans on the surface of the trachea. Infection of Siaα2-3 binding avian viruses was restricted to the lower respiratory tract bronchioles. This finding may diminish the ability of the swine to act as an intermediary in the transmission of avian viruses to humans.

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