Interferons are the proteins that are made and secreted by the cells of immune system. They are produced as a defensive response to viruses as they interfere with virus proliferation. Interferon does not directly interfere with virus multiplication but it stimulates the infected cells and the nearby cells to secrete certain proteins that stop the virus from replicating within the cells. Interferons also have some immunoregulatory functions like they inhibit B lymphocyte activation, enhance the activity of T-lymphocyte, and also increase the capability of natural killer cells of cellular-destruction. Thus interferon enhances the immune system.
There are three classes of interferon: alpha, beta and gamma. The interferons are classified into two types- type 1 and type 2 interferons. Type 1 includes alpha and beta forms and type 2 includes gamma form. Type 1 interferons are produced upon stimulation by the virus and they can be produced by almost any cell and their primary function includes viral resistance in cells. Type 2 interferon is secreted only by T lymphocytes and natural killer cells and its main purpose is to signal the immune system so that immune system can respond to cancerous growth or infectious agent. All the three interferons increase expression of MHC class 1 molecules and thus increase recognition by cytotoxic T cells. Interferon gammas increase the expression of class 2 MHC molecule on antigen presenting cells and thus increase the expression of antigen to helper T cells. Interferon gamma can also increase the ability of macrophages to resist viral infection and to kill other cells if they are infected by the viruses.
Last date updated on September, 2014