Lymphocytes (T- and B-cells) also make substances called lympho-kines. Interferon is one of the lymphokines. When a cell is attacked by a virus, for example, the cell releases interferon. Interferon interacts with other, uninfected cells, stimulating them to make an antiviral protein that protects the second cell from the virus. Interferon can travel through the blood, casting its protective net over different parts of the body. Interferon prompted by one type of virus can protect cells against other viruses, as well as the original one. What’s more, interferons also help regulate other immune cells, for example, by increasing the production of fighting T-cells.