Interferons (IFNs) are natural proteins produced by the cells of the immune system in response to foreign agents such as viruses, parasites and tumor cells.
Interferons belong to the large class of glycoproteins known as cytokines. Interferons are produced by a wide variety of cells in response to the presence of double-stranded RNA, a key indicator of viral infection.
Interferons assist the immune response by halting viral replication, activating specialized immune cells called natural killer(NK) cells and macrophages, increasing antigen presentation to lymphocytes, and inducing the resistance of host cells to viral infection.