The virus transmission undergoes from infected to uninfected cells through either basolateral [36] [37] [38] or apical [39] [40] [41] [42] sides. In the case of influenza virus, cell-free progeny virions are released only from the apical surface of polarized epithelial cells [43] . This releasing polarity is achieved by directed transport of viral membrane proteins to the apical plasma membrane [44] . Indeed, that HA and NA glycoproteins are associated with lipid rafts, and the raft association has been implicated in apical transport [45, 46] .