The human H3N2 influenza viruses was introduced into the human population in 1968 as a novel pandemic virus that emerged through genetic reassortment between human H2N2 and avian influenza virus of H3 subtype. A switch in receptor binding specificity is a critical step for influenza interspecies transmission, as avian influenza viruses typically recognize alpha 2, 3-linked sialiosides while human influenza viruses recognize alpha 2,6-linked sialosides. Further, the receptor binding domain (RBD) that mediates binding to...