Investigating the interaction between influenza and sialic acid : making and breaking the link

Abstract

Since the early 1940s sialic acid (Sia) has been regarded as the primary receptor for influenza virus. This Sia is usually bound to an adjacent galactose (Gal) in an α2-3 or α2-6 configuration. This led to a concept about an interspecies barrier as avian viruses preferentially bind to Sia α2-3 linked to Gal, whereas human viruses have a preference for the Sia α2-6 linked to Gal and that transmission from one species to another would preferentially occur only in a host species in which both types of Sia were present. The viral haemagglutinin binds to Sia to facilitate cellular entry. To release progeny viral particles the second main component of the influenza viral envelope – neuraminidase, cleaves Sia. The viral-receptor interaction was initially investigated using agglutination of red blood cells and later using lectin histochemistry. Recent techniques investigating the HA-Sia/NA-Sia link have employed the use of glycan arrays and virus-like pseudoparticles with STD-NMR.