Abstract
The hemagglutinin (HA) proteins derived from avian influenza viruses bind specifically to the α2-3 sialoglycan (Sia glycan), whereas human-adapted influenza viruses prefer to bind to the α2-6 Sia glycan. A switch of glycan specificity from α2-3 Sia glycan to α2-6 Sia glycan appears to be critical for a virus to become pandemic, therefore, it is important to monitor the influenza virus adaptation to glycan binding. In this article, we described surface plasmon resonance (SPR) methodology for reliable analyses of HA-glycan interactions. The methodology explores the synthetic tetravalent glycans (α2-3 Sia glycan and α2-6 Sia glycans) which facilitates not only the surface capacity of the sensor chip for better SPR signal but also enhance the affinity to the HA resulting an improved sensitivity. To adopt this method routinely for multiple samples of HA or virus, CAP-chip was adopted so that the regeneration of the sensor chip can be achieved. By combining the above developments with BiacoreT100 device, it is possible to program for analyzing multiple samples in continuous fashion under closed environment. Taken together we believe the above methodology is useful in influenza surveillance to monitor the HA adaptations to glycans among influenza viruses.