Innate immune responses to hepatitis C virus

The innate immune response provides the first line of defense against invading viral pathogens. Incoming viruses are sensed by dedicated host factors that, when triggered, initiate multiple signal transduction pathways. Activation of these pathways leads to the induction of highly orchestrated transcriptional programs designed to limit virus replication and spread. In recent years, our understanding of innate immune responses targeting hepatitis C virus (HCV) has increased substantially, largely due to the development of new systems and methodologies to study HCV-host interactions in vitro and in vivo. However, significant gaps still remain. Here, we aim to provide a comprehensive view of the innate immune response to HCV, focusing primarily on knowledge gained from cell culture models of HCV infection, as well as data from human patients infected with HCV. While some paradigms of the host response to HCV revealed in cell culture translate to human infection in vivo, others are less clear. Further insight into the similarities and differences in these systems will not only reveal directions for future studies on HCV immunity, but may also guide the development of novel strategies to control HCV and other viral infections.