Influenza A Virus Receptor Identification in the Respiratory Tract of Quail, Pig, Cow and Swamp Buffalo

Virus infection requires the interaction of a virus protein with the host-cell receptor. The Influenza A virus receptor consists of sialic acid linked to the galactose unit in a alpha 2,3 or alpha 2,6 conformation. Various types of these receptors are expressed differently on the epithelial lining of various animal species. Here we characterized the types of receptors that are expressed in the upper and lower respiratory tracts of cow, buffalo, pig and quail. Our findings demonstrate that SA alpha 2,6-gal linked receptors for human influenza viruses are present in the lower respiratory tract of cow and buffalo, while the SA alpha 2,3-gal linked receptors for avian influenza viruses are prominent in the upper respiratory tract of buffalo. Both types of influenza virus receptors are expressed in the respiratory tract of quail and Pig.