Spectrum of biological activity of interferons.

The interferons comprise a group of proteins first identified by their ability to protect cells against virus infections but also capable of influencing cellular physiology. They are synthesized and secreted by a variety of cell types in response to various inducers. Their effects include antiviral action, inhibition of cell proliferation, modulation of cell differentiation and activation of various cell types in immune system. This review aims to summarize the current state of biology of interferon action with special emphasis on those aspects related to the use of these molecules in antitumoral therapy. The antitumor effects of IFNs results from pleiotropic IFN activity exerted either directly on tumor cells (i.e. antiproliferative effects, effects on oncogene expression, on cell differentiation and enhanced expression of cell surface antigens), or via indirect effects (i.e. activation of effector mechanisms of the host as modulation of the expression of the major histocompatibility antigens, effects on macrophages, NK, T and B cells).