[Production, purification and action mechanism of interferon]

Interferon-alpha is in clinical use for approximately 10 years. Large-scale cell culture and genetic technology had to be developed in the seventies in order to provide sufficient amounts of pure substance for meaningful clinical studies and analysis of modes of action. For its specific effects interferon-alpha has first to bind to specific receptors on the cell membrane. The resulting trans-cytoplasmic signals induce a series of biochemical and cellular events, directly or indirectly responsible for anti-tumor or anti-viral effects. Essential initial events are the induction of synthesis of several new proteins such as 2',5'-oligo-A-synthetase, protein-kinase P1 and major histocompatibility-complex antigens (MHC). Further effects comprise a modulation of the cell cycle, cytostatic effects, induction of differentiation as well as modulation of oncogene expression. Finally immunomodulating effects with effects on the monocyte/macrophage system, natural killer cells and indirectly cytotoxic T-cells have been noted. These effects are illustrated by clinical examples such as chronic viral hepatitis, hairy-cell leukemia and chronic myelogenous leukemia.