Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1985)

The title page shows a scanning electron micrograph of a peripheral B‐lymphocyte magnified 15 000 times (from H. G. Schwick, H. Bräuer, Exempla immunologica , Behringwerke, Medizinische Information, Frankfurt am Main 1980; Picture: Medical Service Munich). In the course of an immune response, the B‐lymphocytes differentiate via several stages of development to form finally the plasma cells, whose only function is the synthesis of antibodies. Such a lymphocyte is accordingly the so‐called precursor of an “antibody factory”. Nature produces heteroclonal or polyclonal antibodies. The production of monoclonal antibodies and their nearly unprecedented advance is described by F. R. Seiler et al. in a review on page 139 ff.