IMMUNOLOGY

Detailed explanation-1: -Interferons (IFNs, /ˌɪntərˈfɪərɒn/) 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 interferons causing nearby cells to heighten their anti-viral defenses.

Detailed explanation-2: -Interferons provide a first line of defence against virus infections by generating an intracellular environment that restricts virus replication and signals the presence of a viral pathogen to the adaptive arm of the immune response.

Detailed explanation-3: -Type I interferon (IFN-alpha and IFN-beta) is secreted by virus-infected cells while type II, immune or gamma interferon (IFN-gamma) is mainly secreted by T cells, natural killer (NK) cells and macrophages.

Detailed explanation-4: -Interferons are formed when most cells are treated with viruses or double-stranded RNA (to form IFN-alpha or beta, or both) or when lymphoid cells are treated with mitogens or the appropriate antigen (to form IFN-gamma).