Type III interferons are expressed by Coxsackievirus-infected human primary hepatocytes and regulate hepatocyte permissiveness to infection

Hepatitis is a common and potentially fatal manifestation of severe Coxsackievirus infections, particularly in newborn children. Little is known of the immune-mediated mechanisms regulating permissiveness to liver infection. It is well established that type I interferons (IFNs) play an important role in the host innate immune response to Coxsackievirus infections. Recent studies have highlighted a role for another IFN family, the type III IFNs (also called IFN-lambda), in anti-viral defence. Whether type III IFNs are produced by hepatocytes during a Coxsackievirus infection remains unknown. Moreover, whether or not type III IFNs protects hepatocytes from a Coxsackievirus infection has not been addressed. In this study, we show that primary human hepatocytes respond to a Coxsackievirus B3 (CVB3) infection by up-regulating the expression of type III IFNs. We also demonstrate that type III IFNs induce an anti-viral state in hepatocytes characterized by the up-regulated expression of IFN-stimulated genes, including IFN-stimulated gene (ISG15), 2'-5'-oligoadenylate synthetase 2 (OAS2), protein kinase regulated by dsRNA (PKR) and myxovirus resistance protein 1 (Mx1). Furthermore, our study reveals that type III IFNs attenuate CVB3 replication both in hepatocyte cell lines and primary human hepatocytes. Our studies suggest that human hepatocytes express type III IFNs in response to a Coxsackievirus infection and highlight a novel role for type III IFNs in regulating hepatocyte permissiveness to this clinically relevant type of virus.