Karel Odink

A glia-derived neurite promoting factor with protease inhibitory activity belongs to the protease nexins

A glia-derived neurite promoting factor (GdNPF) has serine protease inhibitory activity and in addition regulates the migration of neuronal cells. cDNA cloning of GdNPF is necessary for studying the physiological relevance and the mode of action of this protein and similar cell-derived protease inhibitors. Xenopus oocytes injected with rat glioma cells mRNA release this inhibitor. A rat cDNA clone coding for the previously purified glia-derived neurite promoting factor (GdNPF) was isolated upon hybridization-selected translation, followed by immunoprecipitation. The correct identity of this cDNA is proven by the presence of a sequence coding for a tryptic fragment from pure GdNPF. Northern analysis indicates that GdNPF mRNA is found almost exclusively in brain tissue and could be developmentally regulated. The same cDNA clone has been used to isolate full-length rat and human GdNPF cDNA. The deduced human GdNPF amino acid sequence indicates that the protein is a member of a family of cell-derived protease inhibitors named protease nexins.

The Molecular Complex of Macrophage Migration Inhibitory Activity (MIF) and its Role in Inflammatory Reactions

The macrophage migration inhibitory factor (MIF), the first lymphokine ever to be described (1, 2) is released by cultivated lymph node, spleen or peripheral blood mononuclear cells upon antigen or mitogen stimulation. As its production is related to the state of immunity, MIF was considered to be a molecular equivalent of the delayed type hypersensitive (DTH) state. By chemical characterization it became clear that MIF activity was associated with a group of molecules, whose molecular weight ranged from below 10,000 to greater than 60,000 D. Biological activity was found after isoelectric focussing at a pH of 5 and 3. The data obtained were similar with MIF from mitogen-stimulated mouse, guinea pig and human peripheral blood mononuclear cells (3).