Interferon's An immune response against viruses
Interferon, any of several related proteins that are produced by the body’s cells as a defensive response to viruses. They are important modulators of the immune response. Interferon was named for its ability to interfere with viral proliferation. The various forms of interferon are the body’s most rapidly produced and important defense against viruses. Interferons can also combat bacterial and parasitic infections, inhibit cell division, and promote or impede the differentiation of cells. They are produced by all vertebrate animals and possibly by some invertebrates as well. Interferons are categorized as cytokines, small proteins that are involved in intercellular signaling. (Cytokine, any of a group of small, short-lived proteins that are released by one cell to regulate the function of another cell, thereby serving as intercellular chemical messengers.
Cytokines effect changes in cellular behaviour that are important in a number of physiological processes, including reproduction, growth and development, and injury repair. However, they are probably best known for the roles they play in the immune system’s defense against disease-causing organisms). Interferon is secreted by cells in response to stimulation by a virus or other foreign substance, but it does not directly inhibit the virus’s multiplication. Rather, it stimulates the infected cells and those nearby to produce proteins that prevent the virus from replicating within them. Further production of the virus is thereby inhibited and the infection is stemmed.
Interferons also have immunoregulatory functions—they inhibit B-lymphocyte (B-cell) activation, enhance T-lymphocyte (T-cell) activity, and increase the cellular-destruction capability of natural killer cells. Three forms of interferon—alpha (α), beta (β), and gamma (γ)—have been recognized. These interferons have been classified into two types: type I includes the alpha and beta forms, and type II consists of the gamma form. This division is based on the type of cell that produces the interferon and the functional characteristics of the protein.
Type I interferons can be produced by almost any cell upon stimulation by a virus; their primary function is to induce viral resistance in cells. Type II interferon is secreted only by natural killer cells and T lymphocytes; its main purpose is to signal the immune system to respond to infectious agents or cancerous growth. #Second line of defence #interferons #AnitiviralActivityOfInterferons