IFN-alpha is a type of protein known as an interferon, which plays a crucial role in the immune response. It is produced by cells in response to viral infections and helps to regulate the activity of the immune system. By signaling neighboring cells, IFN-alpha enhances their ability to fight off viruses and can also activate immune cells like T-cells and natural killer cells. In addition to its role in fighting infections, IFN-alpha is used as a treatment for certain diseases, including some types of cancer and viral infections like hepatitis C. It can help slow the growth of cancer cells and improve the immune response against the virus, making it an important tool in medical therapies.