[Cellular receptors and regulator proteins reacting with C3 activation products]

The central protein of the complement system is C3. The biological role of C3 includes development of inflammation, transport of immune complexes, phagocytosis and immunoregulation. These functions are mediated by the interaction between activated C3 and specific cellular C3 ligands. The article reviews aspects of the biological function of cell-bound C3 receptors and regulatory molecules, and the role of these molecules in autoimmune and inflammatory diseases.