Finally, the ability of HCVpp to infect HepG2 expressing CD81ΔC with comparable efficiency independent of their polarized status highlights a potential role for this domain in restricting HCV infection of polarized cells, in contrast to the many reports suggesting that infection is limited by the access of virus to tight junction proteins claudin-1 and occludin (Brazzoli et al., 2008; Burlone and Budkowska, 2009; Delorme-Axford and Coyne, 2011). The gene discussed is CLDN1; the disease is infection.