The evolving role of interferons in viral eradication strategies

Interferons (IFNs) are a family of pleiotropic cytokines that are released when viral infection is sensed by pattern recognition receptors. They induce an antiviral state in target cells through influencing the expression of hundreds of genes termed IFN-stimulated genes (ISGs), which interfere with the replication of viruses in wide-ranging ways, and they have stimulatory effects on antiviral cell-mediated immunity. Although the role of therapeutic IFNs in the management of infectious diseases has predominantly been restricted to the treatment of chronic hepatotropic viruses, IFNs have effects on the replication of diverse families of viruses in cell culture models, and the potential to harness our endogenous defence system through therapeutic modulation of IFN pathways remains a tantalising prospect for both the broad-spectrum and tailored treatment of viral infections. Additionally, the study of the IFN system has become crucial to our understanding of host/pathogen molecular interactions, which provides plentiful targets for small molecule inhibitors of infection. Although the emergence of directly acting antivirals (DAAs) has resulted in the displacement of pegylated IFNα (pegIFNα) for the treatment of HCV, recent findings have suggested potential roles for IFNs and IFN-related therapies in HIV and HBV eradication strategies, opening up a new avenue of research for this important family of cytokines.