L-SIGN (CD209L) and DC-SIGN (CD209) mediate transinfection of liver cells by hepatitis C virus.

Target cell tropism of enveloped viruses is regulated by interactions between viral and cellular factors during transmission, dissemination, and replication within the host. Binding of viral envelope glycoproteins to specific cell-surface receptors determines susceptibility to viral entry. However, a number of cell-surface molecules bind viral envelope glycoproteins without mediating entry. Instead, they serve as capture receptors that disseminate viral particles to target organs or susceptible cells. We and others recently demonstrated that the C type lectins L-SIGN and DC-SIGN capture hepatitis C virus (HCV) by specific binding to envelope glycoprotein E2. In this study, we use an entry assay to demonstrate that HCV pseudoviruses captured by L-SIGN+ or DC-SIGN+ cells efficiently transinfect adjacent human liver cells. Virus capture and transinfection require internalization of the SIGN-HCV pseudovirus complex. In vivo, L-SIGN is largely expressed on endothelial cells in liver sinusoids, whereas DC-SIGN is expressed on dendritic cells. Capture of circulating HCV particles by these SIGN+ cells may facilitate virus infection of proximal hepatocytes and lymphocyte subpopulations and may be essential for the establishment of persistent infection.