Infection with human H1N1 influenza virus affects the expression of sialic acids of metaplastic mucous cells in the ferret airways.

Glycans terminating in sialic acids serve as receptors for influenza viruses. In this study ferrets were infected with influenza virus A/New Caledonia/20/99, and the in situ localization of sialic acids linked alpha2-3 and alpha2-6 in the airways was investigated in infected and non-infected animals by use of sialic acid detecting lectins and a monoclonal antibody towards the Sialyl-Tn antigen. The goblet cells in the bronchi from non-infected ferrets expressed Sialyl alpha 2-6Gal glycans, while the seromucinous glands in the submucosa expressed Sialyl alpha 2-3Gal glycans. In the infected animals, the surface epithelial cells in some bronchi showed metaplasia and expressed the Sialyl-Tn antigen: Sialyl alpha 2-6GalNAc-O-Thr/Ser. The submucosal tracheal glands in these animals showed increased expression of both Sialyl alpha 2-3 and Sialyl alpha 2-6 epitopes.