Innate immunity is a branch of the immune system that is responsible for controlling the early events of pathogen infection. One of the key components of the innate immune systems arsenal are the interferon (IFN) cytokines. IFNs are small signalling proteins that are released by cells in response to invading pathogens, and viruses in particular. They are named for their ability to interfere with viral replication. The result of IFN signalling is the up-regulation of a diverse collection of genes termed interferon-stimulated genes (ISGs). These genes act in synchrony to limit the replication of viruses. The protein products of ISGs are involved in a multitude of cellular pathways that limit replication and additionally intercept viral proteins and nucleic acid directly. Some of these ISGs are mediators of an important cell-death response, apoptosis. Apoptosis is a vital component of innate immune signalling and controls viral replication by sacrificing the infected cell to limit further infection of neighbouring cells. The function of specific ISGs in mediating this response is poorly understood.