CD81 and infection: HCV encodes two envelope glycoproteins, E1 and E2, which play crucial roles in the initiation of infection by mediating the interaction between the virus and the host cell membrane.3,4 While E2 is thought to initiate viral attachment, E1 may be involved in virus-cell membrane fusion.4,5 E2 has been proposed to be responsible for recognizing and binding to cellular receptors.6 CD81 has been identified as a critical co-receptor for HCV particle entry.7