What are Interferons ? How these inhibit the multiplication of viruses? Name two diseases controlled by interferons.

Explanation

Certain animal cells infected with viruses produce polypeptides called Cytokines. One type of cytokine, an interferon, diffuses to healthy neighbouring cells and stimulates them to produce biochemicals that block viral replication. When these cells become infected, the viruses are unable to take over the protein synthetic machinery to manufacture more of themselves. The spread of the infection halts.
Interferon is specific to the species, therefore, only human interferon can be used in humans. These have been successfully used in treating influenza and hepatitis but have not been successful against cancer.