ABSTRACT
This chapter reviews the data concerning the effect of interferon on the infection of mammalian cells by animal viruses, with special emphasis on its effect on the interference of the latter with the host cell and the molecular basis of this activity. Interferon (IFN) was able to trigger cellular mechanisms responsible for the establishment of the so-called antiviral state that appeared to be dependent on the presence of the cell nucleus and ribonucleic acid and protein synthesis. IFN was discovered as an antiviral factor that afforded resistance against viral infection. Since then, it has been traditionally considered to protect cells from the death and cytopathic effect caused by cytocidal animal viruses. Depending on the cell line or virus studied, a blockade at different stages of viral replication has been detected. The IFN-induced increase in protein kinase activity observed in vitro has also been implicated in the antiviral action of IFN.
