CD81 and infection: HCV initiates infection by attaching to molecules or receptors at the cell surface and current evidence supports an essential role for scavenger receptor class B member I (SR-BI), tetraspanin CD81 and tight-junction proteins claudin-1 and occludin in clathrin-dependent particle endocytosis (Meredith et al., 2012; Ploss & Evans, 2012).