Hong Kong Med J 2009;15(Suppl 4):S16-20
Sialic acid and receptor expression on the respiratory tract in normal subjects and H5N1 and non-avian influenza patients
JM Nicholls, JSM Peiris, Y Guan
Department of Pathology, The University of Hong Kong
1. Influenza virus binds to cell receptors via sialic acid (SA)–linked glycoproteins. An accurate knowledge of SA expression is important in understanding influenza pathogenesis. The influenza viruses circulating in Hong Kong bind to the SA_2,6Gal receptor whilst avian influenza (such as H5N1) bind to SA_2,3Gal receptors.
2. SA_2,3Gal and SA_2,6Gal are widely distributed in the upper and lower respiratory tract as determined by lectin binding experiments.
3. Expression of SA_2,3Gal in the respiratory tract was correlated with infection of lung and nasopharyngeal tissues by a range of H5N1 viruses. H5N1 infection of both the upper and lower respiratory tract may have important implications on the spread of H5N1 influenza virus from patient to patient.
4. Ex vivo tissue culture models should be used more widely to determine the ability of tissues to be infected with H5N1 viruses.