Final answer:
Interferons are cytokines that aid in fighting off viral infections by signaling to uninfected cells and activating immune responses. They are crucial in controlling viral replication but cannot completely eliminate viruses without the help of cytotoxic T cells.
Step-by-step explanation:
Interferons are particularly useful against infections with viruses. They are a class of cytokines that are released by cells infected with a virus. Interferons signal to neighboring uninfected cells to produce compounds interfering with viral replication and activate other immune responses. Although they can slow viral replication and are used in treating some viral diseases such as hepatitis B and C, they cannot completely eliminate the virus. Instead, the cytotoxic T cell response is critical for eventually overwhelming the virus and killing infected cells to prevent the virus from completing its replicative cycle. Interferons are important in viral infection control but are not entirely virus-specific and also play roles in tumor surveillance and activating immune cells to destroy RNA and reduce protein synthesis.