Neu5Acα2,6Gal and Neu5Acα2,3Gal receptor specificities on influenza viruses determined by a waveguide-mode sensor.

To characterize the differences in the receptor-binding specificities of human and avian influenza viruses with glycan chains, the authors performed binding analyses using an evanescent field-coupled waveguide-mode biosensor. The experiments were performed on intact viruses and hemagglutinin proteins, using gold-nanoparticle-conjugated Neu5Acα2,6Gal and Neu5Acα2,3Gal glycan chains. Several influenza viruses belonging to subtypes H3N2 (A/Udorn/307/1972, A/Shandong/9/1993, A/Kiev/301/1994, A/Panama/2007/1999, A/Wisconsin/67/2005 and A/Brisbane/10/2007), H1N1 (A/Brisbane/59/2007 and A/California/07/2009) and H5N1 (A/chicken/India/NIV33487/2006) were used. High levels of glycan-based discrimination were observed with the H3N2 strain A/Brisbane/10/2007 due to its specificity with Neu5Acα2,6Gal, but not with Neu5Acα2,3Gal. Possible amino acid residues responsible for the discrimination of human and avian influenza viruses are discussed. These types of sensor-based discriminatory analyses would be very useful for distinguishing between influenza pandemics, especially during the transition and overlapping periods of human and avian influenza viruses with evolutionary changes.