Final answer:
Interferons are cytokines released by infected cells to signal and activate neighboring cells to fight against viral infections.
Step-by-step explanation:
Interferons play an important role in the defense against diseases, particularly viral infections. When a cell is infected with a virus, it releases interferons as a warning to nearby uninfected cells. These interferons signal the uninfected cells to destroy viral RNA and reduce protein synthesis, as well as induce apoptosis in infected cells. Additionally, interferons activate immune cells, such as macrophages, to help fight against the infection.