Antiviral Actions of Interferons in Animals

Abstract

Interferon (IFN) was discovered as an antiviral agent during studies on virus interference (180, 294). Isaacs and Linden- mann reported in 1957 that influenza virus-infected chick cells produced a secreted factor that mediated the transfer of a virus-resistant state active against both homologous and het- erologous viruses (180). This seminal observation, along with similar findings described by Nagano and Kojima in 1958 (294), set the stage for subsequent studies that led to the elucidation of the IFN system in exquisite detai