[Human interferons -- features and chances (author's transl)]

Interferons are soluble cellular products secreted by vertebrate cells in response to a wide variety of inducers. They confer resistance against many different viruses, inhibit proliferation of normal and malignant cells, impede multiplication of intracellular parasites, enhance macrophage and granulocyte phagocytosis, augment natural killer cell activity, and show several other immunomodulatory functions. In viral infections, interferon controls the spread of viruses by inhibiting viral protein synthesis and/or nucleic acid replication and by activating cellular immune responses which effectively eliminate virus-infected cells. Immune interferon, produced in a cellular immune response as the result of an infection, tumour, or hypersensitivity reaction, governs the local immune response to the abrogation of that tumour or other injury by directly reducing cell multiplication and recruiting cytotoxic cells. Clinical trials have shown some effectiveness of interferon in the treatment of chronic viral infections as well as some possible antitumour effects. Because of the extreme scarcity of human interferon and the use of highly impure preparations, the results to date are not conclusive. Therapeutic effectiveness rather than prophylactic effects, has still to be proved by controlled clinical studies with purified interferon under economically feasible conditions.