<unk> s <unk> s, ) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release<unk> s causing nearby cells to heighten their anti-viral defenses.<unk> s belong to the large class of proteins known as cytokines, molecules used for communication between cells to trigger the protective defenses of the immune system that help eradicate pathogens.<unk> s are named for their ability to "interfere" with viral replication by protecting cells from virus<unk> ections. However, virus-encoded genetic elements have the ability to antagonize the<unk>  response contributing to viral pathogenesis and viral diseases.<unk> s also have various other functions: they activate immune cells, such as natural killer cells and macrophages, and they increase host defenses by up-regulating antigen presentation by virtue of increasing the expression of major histocompatibility complex (MHC) antigens. Certain symptoms of<unk> ections, such as fever, muscle pain and "flu-like symptoms", are also caused by the production of<unk> s and other cytokines. More than twenty distinct<unk>  genes and proteins have been identified in animals, including humans. They are typically divided among three classes: Type I<unk> , Type II<unk> , and Type III<unk> .<unk> s belonging to all three classes are important for fighting viral<unk> ections and for the regulation of the immune system.
Interferon
Pegylated interferon
Peginterferon alfa-2a
Peginterferon alfa-2b
Ropeginterferon alfa-2b
Peginterferon beta-1a
Ruxolitinib
Rituximab