Biological activity of gamma interferon.

Gamma interferon (IFN) is mainly produced, under natural conditions, by antigen-specific T lymphocytes during the immune response. Cooperation with macrophages is required. Although discovered in 1965 as an antiviral agents, today this type of IFN is considered a lymphokine deeply involved in the regulation of several immunological reactions such as: cytotoxicity; expression of surface antigens, mainly MHC antigens; cellular differentiation; antibody production; macrophage activation. In this review the authors discuss some aspects of the biology of gamma IFN as pleiotropic lymphokine as well as the cellular events leading to gamma IFN production.