Final answer:
Interferon-alpha and -beta are synthesized by cells infected with a virus and help protect nearby uninfected cells by reducing protein synthesis, inducing apoptosis in infected cells, and activating immune cells. They defend against viral infections and contribute to tumor surveillance.
Step-by-step explanation:
Interferon-alpha and -beta (IFN-a and IFN-b) are synthesized by cells infected with a virus. These interferons function as early-acting cytokines and play a critical role in the body's defense against viral infections. They are released as signals to warn and protect nearby uninfected cells. The presence of these interferons triggers a multi-faceted response, which includes the alteration of gene expression in neighboring cells; this leads to a marked decrease in protein synthesis and an increase in antiviral defenses. Additionally, interferons help activate immune cells and can stimulate infected cells to undergo apoptosis, hence preventing further spread of the virus.
Interferons not only fight against viruses but also play a role in tumor surveillance and the defensive response against certain bacteria. The activation of macrophages and cooperation with the adaptive immune response further enhance their effectiveness. Specifically, IFN-a and IFN-b are particularly useful in protecting cells from viral infections, which highlights their importance in the immune system's arsenal.