Schematic interactions and relationships among different human noroviruses with a complete product of human HBGA.

<p>Representative strains of different genotypes in the two major genogroups (GI and GII) of human noroviruses are shown according to their target saccharides. Arrows indicate interactions between individual noroviruses and specific residues of human HBGAs. Dashed lines indicate a weaker interaction. The five circles in different colors represent the five saccharide residues of a complete product of an H-related HBGA (H, A, B, Le^b, or Le^y). The curved dashed arrows indicate two major binding groups, the A/B/H (blue) and the Lewis/H (black) binding groups, according to their target residues on human HBGAs. The binding specificity and affinity of these norovirus strains were determined in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1000983#ppat.1000983-Huang1" target="_blank">[30]</a>.