Interferons increase expression of class I MHC molecules and thus promote recognition by cytotoxic T cells. They can activate NK cells that can kill virus- infected cells. They play an important role in the first line of defense against viral infections.
Research work revealed that, these substances could prevent not only viral infections but also suppress the growth of cancers in some laboratory animals.
The gene that codes this cytokine is switched on in an infected cell. The interferon synthesized and secreted to the surroundings warns other viruses. The pre warned cell then produces translation inhibition factor to inhibit viral replication through reduced translation initiation and reduced protein synthesis.
Interferon acts as an inducer and causes increased production of the p53 gene product in virus infected cells. This promotes apoptosis, limiting the ability of the virus to spread.